Prediction of Blast-Induced Ground Vibration Intensity in Open-Pit Mines Using Unmanned Aerial Vehicle and a Novel Intelligence System     

Bui  Xuan-Nam  Choi  Yosoon  Atrushkevich  Victor  Nguyen  Hoang  Tran  Quang-Hieu  Long  Nguyen Quoc  Hoang  Hung-Thang 《Natural Resources Research》2020,29(2):771-790

Natural Resources Research - Predicting and reducing blast-induced ground vibrations is a common concern among engineers and mining enterprises. Dealing with these vibrations is a challenging issue...  相似文献   

A Novel Artificial Intelligence Approach to Predict Blast-Induced Ground Vibration in Open-Pit Mines Based on the Firefly Algorithm and Artificial Neural Network     

Shang  Yonghui  Nguyen  Hoang  Bui  Xuan-Nam  Tran  Quang-Hieu  Moayedi  Hossein 《Natural Resources Research》2020,29(2):723-737

Natural Resources Research - The primary purpose of this study was to develop a novel hybrid artificial intelligence model, with a robust performance, to predict ground vibration induced by bench...  相似文献   

Groundwater recharge in suburban areas of Hanoi,Vietnam: effect of decreasing surface-water bodies and land-use change     

Kuroda  Keisuke  Hayashi  Takeshi  Do  An Thuan  Canh  Vu Duc  Nga  Tran Thi Viet  Funabiki  Ayako  Takizawa  Satoshi 《Hydrogeology Journal》2017,25(3):727-742

Over-exploited groundwater is expected to remain the predominant source of domestic water in suburban areas of Hanoi, Vietnam. In order to evaluate the effect on groundwater recharge, of decreasing surface-water bodies and land-use change caused by urbanization, the relevant groundwater systems and recharge pathways must be characterized in detail. To this end, water levels and water quality were monitored for 3 years regarding groundwater and adjacent surface-water bodies, at two typical suburban sites in Hanoi. Stable isotope (δ¹⁸O, δD of water) analysis and hydrochemical analysis showed that the water from both aquifers and aquitards, including the groundwater obtained from both the monitoring wells and the neighboring household tubewells, was largely derived from evaporation-affected surface-water bodies (e.g., ponds, irrigated farmlands) rather than from rivers. The water-level monitoring results suggested distinct local-scale flow systems for both a Holocene unconfined aquifer (HUA) and Pleistocene confined aquifer (PCA). That is, in the case of the HUA, lateral recharge through the aquifer from neighboring ponds and/or irrigated farmlands appeared to be dominant, rather than recharge by vertical rainwater infiltration. In the case of the PCA, recharge by the above-lying HUA, through areas where the aquitard separating the two aquifers was relatively thin or nonexistent, was suggested. As the decrease in the local surface-water bodies will likely reduce the groundwater recharge, maintaining and enhancing this recharge (through preservation of the surface-water bodies) is considered as essential for the sustainable use of groundwater in the area.

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Observational climatology and characteristics of wintertime atmospheric blocking over Ural–Siberia     

Ho Nam Cheung  Wen Zhou  Yaping Shao  Wen Chen  Hing Yim Mok  Man Chi Wu 《Climate Dynamics》2013,41(1):63-79

This study investigates the climatological aspects and temporal characteristics of wintertime Ural-Siberian blocking (USB, centered over 30°–100°E), for the period 1980/1981–2009/2010. Sixty-eight events are identified and their physical structure is diagnosed using thermodynamic and geostrophic vorticity tendency equations. In climatology, horizontal advections play a fundamental role in constructing a USB event, in which the anticyclonic center is a warm core in the troposphere and a cold core in the lower stratosphere. The decay of the thermal structure is related to diabatic cooling along the vertical structure and warm advection in the lower stratosphere. Meanwhile, the collapse of the height structure is caused primarily by cyclonic vorticity advection. A strong interrelationship exists between the intensity and extension of USB events. The temporal characteristics of USB events are analyzed by examining strong and weak events, which are of high and low intensity. The strong events are probably preceded by an open ridge over Europe and a cyclogenesis over the Mediterranean Sea, and their formation is followed by the stronger amplification of a Rossby wave packet across Eurasia. On the other hand, the weak events are likely to be triggered by surface cold anomalies over Siberia. Overall, the evolution of a USB event forms a dynamic linkage with the Siberian high, in which the decay stage of the USB event is accompanied by a southeastward migration of the Siberian high and a subsequent cold air outbreak in East Asia. These results advance our understanding of USB and its relationship with East Asian winter monsoon activities.  相似文献   

基于GIS的移动蜂窝网络场强预测研究     

陈晓勇  吴华玲  Tran Minh Tri 《武汉大学学报(信息科学版)》2011,36(10):1135-1139

利用GIS能将蜂窝网络数据库中空间与非空间数据相结合的优势,来提供必要的参数,以更准确地预测蜂窝网络的覆盖强度,研究设计了一种基于COST-231-Walfisch-Ikegami的GIS模型,用来预测越南胡志明市移动蜂窝网络的信号强度,该模型可以帮助确定无线电的视距和非视距情况。该模型对路径方向损失、多屏衍射损耗和阴影增益进行了更精确的预测。实验中采用的地图比例尺是1∶2 000,采用的平均楼层高度为3 m。统计结果表明,该GIS模型预测的路径损耗克服了每个基站的实测路径损耗,在市区可以用来预测微蜂窝覆盖范围。  相似文献   

A new method for estimating driven pile static skin friction with instrumentation at the top and bottom of the pile     

Khiem T. Tran  Michael McVay  Rodrigo Herrera  Peter Lai 《Soil Dynamics and Earthquake Engineering》2011

A numerical technique is presented to estimate ultimate skin friction of a driven pile using instrumentation installed at the top and bottom of a pile. The scheme is based on an analytical solution of the 1D wave equation with static skin friction and damping along with a genetic algorithm for solution. Specifically, acceleration and strains measured at both the top and bottom of the pile are used to develop an observed Green's function, which is matched to an analytical Green's function, which is a function of secant stiffness and viscous damping. Requiring 1–3 s of analysis time per blow, the algorithm provides a real time assessment of average skin friction along the pile. The technique was applied to four driven piles having ultimate skin frictions varying from 700 to 2000 kN, with the predicted skin frictions generally consistent with measured static load test results.  相似文献   

Mechanism of tremolite carbonation     

Kyoung Won RyuMyung Gyu Lee  Young Nam Jang 《Applied Geochemistry》2011,26(7):1215-1221

The direct aqueous carbonation of fibrous tremolite was investigated by TEM, powder XRD, and FT-IR to elucidate the transformation mechanism of tremolite into calcite. The TEM study revealed that tremolite dissolves along the weak cleavage on (1 0 0) and (1 1 0) and the cleavage fragment fibers. The preferential release of Ca, relative to Si or Mg, into the solution resulted in the crystallization of compositionally homogeneous calcite and in the concurrent formation of proto-saponite. X-ray diffraction analysis revealed that the amount of product calcite increased rapidly within 15 min. Subsequently, after a 5 h carbonation period, it increased slowly to about 60%. The product calcite is euhedral. In contrast, the unreacted tremolite grains retain the original crystal structure even after prolonged carbonation. The morphological modification of tremolite from fibrous to round may have important implications for the elimination of its toxicity.  相似文献   

The Cenozoic on-shore basins of Northern Vietnam: Biostratigraphy,vertebrate and invertebrate faunas     

Madelaine Böhme  Jérôme Prieto  Simon Schneider  Nguyen Viet Hung  Do Duc Quang  Dang Ngoc Tran 《Journal of Asian Earth Sciences》2011,40(2):672-687

A first account of paleontological data from three Cenozoic on-shore basins in Northern Vietnam, i.e. the Na Duong, Cao Bang, and Hang Mon basins, reveals a rich fossil fauna and flora of supposed Oligocene age, offering a great potential for taxonomic, paleoenvironmental, and paleobiogeographic studies. Two excavation campaigns unearthed well-preserved fossil remains of mammals, crocodiles, at least six turtle species, some 20 fish taxa, some other 20 mollusc species, and different plant remains. The majority of these taxa are regarded as new to science. However, close affinities to modern faunas of northern Southeast Asia demonstrate the importance of these fossils for an evaluation of the biological history of this modern biodiversity hot spot. Moreover, the fossil assemblages may help to disentangle the intricate Cenozoic tectonic evolution of Southeast Asia by application of paleobiogeographic modelling. Finally, the discovery of complex paleo-food-webs and the presence of several taxa indicative of certain ecological conditions provide a solid base for autecologic, synecologic and paleoclimatic studies. The potential biostratigraphic value of the macrofauna has to be demonstrated yet, as evolutionary concepts for most of the respective groups have not been proposed to date.  相似文献   

Simulation of marine controlled source electromagnetic measurements using a parallel fourier <Emphasis Type="Italic">hp</Emphasis>-finite element method     

David Pardo  Myung Jin Nam  Carlos Torres-Verdín  Michael G. Hoversten  Iñaki Garay 《Computational Geosciences》2011,15(1):53-67

We introduce a new numerical method to simulate geophysical marine controlled source electromagnetic (CSEM) measurements for the case of 2D structures and finite 3D sources of electromagnetic (EM) excitation. The method of solution is based on a spatial discretization that combines a 1D Fourier transform with a 2D self-adaptive, goal-oriented, hp-Finite element method. It enables fast and accurate simulations for a variety of important, challenging and practical cases of marine CSEM acquisition. Numerical results confirm the high accuracy of the method as well as some of the main physical properties of marine CSEM measurements such as high measurement sensitivity to oil-bearing layers in the subsurface. In our model, numerical results indicate that measurements could be affected by the finite oil-bearing layer by as much as 10⁴% (relative difference). While the emphasis of this paper is on EM simulations, the method can be used to simulate different physical phenomena such as seismic measurements.  相似文献   

滇西哀牢山构造带:结构与演化   总被引：19，自引：0，他引：19  

刘俊来  唐渊  宋志杰  Tran My Dung  翟云峰  吴文彬  陈文 《吉林大学学报(地球科学版)》2011,41(5):1285-1303

哀牢山构造带是藏东(东南亚)地区的一条重要线性构造,它分隔了扬子—华南地块与印支地块,并保存了多阶段复杂大地构造演化的记录。哀牢山构造带内由东向西依次发育了晚太古代—新元古代深变质岩系、新生代构造-岩浆活动带(剪切带)、金平—沱江晚二叠—早三叠世裂谷带残余和哀牢山早石炭世—早三叠世混杂岩带。具有不同特点的地质单元间被以新生代为主发育的断裂构造所间隔;而不同时期异地就位或混合岩化成因的花岗质岩石在构造带中普遍存在。哀牢山构造带在不同地质历史阶段具有多重大地构造属性,总体上经历了3个重要大地构造演化阶段:前特提斯演化、特提斯演化和新生代陆内演化阶段。前特提斯演化时期,主体部分(尤其是其东部带)具有亲扬子地块的属性,保留了自晚太古代到新元古代地壳演化的记录。一直到早古生代时期,哀牢山构造带的大地构造属性与扬子—华南地区依然具有密切的亲缘关系。自晚古生代—早中生代时期古特提斯洋打开之后,该带与华南-扬子板块之间分化成2个属性不同的构造域,始于早石炭世打开的哀牢山洋与始于早二叠世打开的金平—沱江洋依次消亡。特提斯洋的闭合,一方面形成了古哀牢山造山带,同时使得扬子—华南地块与印支地块回复到一个统一的陆内环境中;印度—欧亚板块之间的交互作用,对这一地区有着深刻的影响,相继形成了早新生代哀牢山造山带、晚渐新世—早中新世造山后区域性伸展与高钾碱性岩浆活动性和晚渐新世—早中新世印支地块的大规模南东向逃逸、哀牢山大型左行走滑剪切作用及伴生的钙碱性岩浆活动性。  相似文献