Controlling geological and hydrogeological processes in an arsenic contaminated aquifer on the Red River flood plain,Vietnam   总被引：1，自引：0，他引：1  

Flemming Larsen  Nhan Quy Pham  Nhan Duc Dang  Dieke Postma  Søren Jessen  Viet Hung Pham  Thao Bach Nguyen  Huy Duc Trieu  Luu Thi Tran  Hoan Nguyen  Julie Chambon  Hoan Van Nguyen  Dang Hoang Ha  Nguyen Thi Hue  Mai Thanh Duc  Jens Christian Refsgaard 《Applied Geochemistry》2008

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Correction to: Hydro-geochemical characteristics of the groundwater resources in the southern part of the Red River’s Delta plain,Vietnam     

Hoan V. Hoang  Lam V. Nguyen  Nhan D. Dang  Frank Wagner  Nhan Q. Pham 《Environmental Earth Sciences》2018,77(20):714

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Predicting rock size distribution in mine blasting using various novel soft computing models based on meta-heuristics and machine learning algorithms     

Chengyu Xie  Hoang Nguyen  Xuan-Nam Bui  Yosoon Choi  Jian Zhou  Thao Nguyen-Trang 《地学前缘(英文版)》2021,12(3):101108

Blasting is well-known as an effective method for fragmenting or moving rock in open-pit mines. To evaluate the quality of blasting, the size of rock distribution is used as a critical criterion in blasting operations. A high percentage of oversized rocks generated by blasting operations can lead to economic and environmental damage. Therefore, this study proposed four novel intelligent models to predict the size of rock distribution in mine blasting in order to optimize blasting parameters, as well as the efficiency of blasting operation in open mines. Accordingly, a nature-inspired algorithm (i.e., firefly algorithm – FFA) and different machine learning algorithms (i.e., gradient boosting machine (GBM), support vector machine (SVM), Gaussian process (GP), and artificial neural network (ANN)) were combined for this aim, abbreviated as FFA-GBM, FFA-SVM, FFA-GP, and FFA-ANN, respectively. Subsequently, predicted results from the abovementioned models were compared with each other using three statistical indicators (e.g., mean absolute error, root-mean-squared error, and correlation coefficient) and color intensity method. For developing and simulating the size of rock in blasting operations, 136 blasting events with their images were collected and analyzed by the Split-Desktop software. In which, 111 events were randomly selected for the development and optimization of the models. Subsequently, the remaining 25 blasting events were applied to confirm the accuracy of the proposed models. Herein, blast design parameters were regarded as input variables to predict the size of rock in blasting operations. Finally, the obtained results revealed that the FFA is a robust optimization algorithm for estimating rock fragmentation in bench blasting. Among the models developed in this study, FFA-GBM provided the highest accuracy in predicting the size of fragmented rocks. The other techniques (i.e., FFA-SVM, FFA-GP, and FFA-ANN) yielded lower computational stability and efficiency. Hence, the FFA-GBM model can be used as a powerful and precise soft computing tool that can be applied to practical engineering cases aiming to improve the quality of blasting and rock fragmentation.  相似文献   

Multifractal behaviour of long‐term karstic discharge fluctuations     

D. Labat  C. T. Hoang  J. Masbou  A. Mangin  I. Tchiguirinskaia  S. Lovejoy  D. Schertzer 《水文研究》2013,27(25):3708-3717

Karstic watersheds are highly complex hydrogeological systems that are characterized by a multiscale behaviour corresponding to the different pathways of water in these systems. The main issue of karstic spring discharge fluctuations consists in the presence and the identification of characteristic time scales in the discharge time series. To identify and characterize these dynamics, we acquired, for many years at the outlet of two karstic watersheds in South of France, discharge data at 3‐mn, 30‐mn and daily sampling rate. These hydrological records constitute to our knowledge the longest uninterrupted discharge time series available at these sampling rates. The analysis of the hydrological records at different levels of detail leads to a natural scale analysis of these time series in a multifractal framework. From a universal class of multifractal models based on cascade multiplicative processes, the time series first highlights two cut‐off scales around 1 and 16 h that correspond to distinct responses of the aquifer drainage system. Then we provide estimates of the multifractal parameters α and C₁ and the moment of divergence q_D corresponding to the behaviour of karstic systems. These results constitute the first estimates of the multifractal characteristics of karstic spingflows based on 10 years of high‐resolution discharge time series and should lead to several improvements in rainfall‐karstic springflow simulation models. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Finite element analysis of the effect of corrosion on the behavior of reinforced earth walls     

Truong‐Linh Chau  Emmanuel Bourgeois  Alain Corfdir 《国际地质力学数值与分析法杂志》2012,36(15):1741-1756

A simple model for the corrosion‐induced loss of stiffness and strength of the steel strips of earth‐reinforced walls was introduced in a finite element simulation of the long‐term behavior of the wall, in which the backfill‐strips interactions are taken into account by means of a generalized homogenization procedure (called a multiphase model). The results show an initial phase of slow displacements induced by the loss of stiffness, followed after a few decades by a steep acceleration of the displacements, leading to wall failure. The influences of the parameter controlling corrosion, the backfill cohesion and the heterogeneity of the corrosion process are discussed. Results are used to discuss a strategy for reinforced earth wall surveillance. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Adaptive neuro-fuzzy inference system coupled with shuffled frog leaping algorithm for predicting river streamflow time series     

Babak Mohammadi  Nguyen Thi Thuy Linh  Ali Najah Ahmed  Jana Vojteková  Yiqing Guan 《水文科学杂志》2020,65(10):1738-1751

ABSTRACT

Accurate runoff forecasting plays a key role in catchment water management and water resources system planning. To improve the prediction accuracy, one needs to strive to develop a reliable and accurate forecasting model for streamflow. In this study, the novel combination of the adaptive neuro-fuzzy inference system (ANFIS) model with the shuffled frog-leaping algorithm (SFLA) is proposed. Historical streamflow data of two different rivers were collected to examine the performance of the proposed model. To evaluate the performance of the proposed ANFIS-SFLA model, six different scenarios for the model input–output architecture were investigated. The results show that the proposed ANFIS-SFLA model (R² = 0.88; NS = 0.88; RMSE = 142.30 (m³/s); MAE = 88.94 (m³/s); MAPE = 35.19%) significantly improved the forecasting accuracy and outperformed the classic ANFIS model (R² = 0.83; NS = 0.83; RMSE = 167.81; MAE = 115.83 (m³/s); MAPE = 45.97%). The proposed model could be generalized and applied in different rivers worldwide.  相似文献   

Body-wave dispersion in the Friuli focal area     

P. Hoang Trong  M. Granet 《Physics of the Earth and Planetary Interiors》1980,21(1):31-37

The differential dispersion of P- and S- body waves is studied in the Friuli area. We estimate theoretically the respective contributions of the source, from dislocation models, and of the propagation, from the Futterman model. We demonstrate the possible existence of differential dispersion, which is interpreted as being due to attenuation. The quality factor Q_P deduced from this hypothesis shows a regional variation from 15 to 210. Results also indicate a possible dependence of Q_P on frequency in the range 5–40 Hz.  相似文献   

The sediment load and deposition by river discharge and their relation to organochlorine pesticides pollutants in the sediment bottom of Nha Trang Bay,Vietnam     

Du  Hoang Trung  Kunzmann  Andreas 《Ocean Science Journal》2015,50(2):455-466

Ocean Science Journal - Based on previous results from the “River reef impact studies project that was carried out as a co-operation programme between ZMT (Germany) and NIO (Vietnam) from...  相似文献   

Spread-F during the magnetic storm of 22 January 2004 at low latitudes: Effect of IMF-Bz in relation to local sunset time     

R G Rastogi  H Chandra  P Janardhan  Thai Lan Hoang  Louis Condori  T K Pant  D S V V D Prasad  B Reinisch 《Journal of Earth System Science》2014,123(6):1273-1285

The paper describes the results of spread-F at low latitude stations around the world during the magnetic storm starting at 0130 UT on 22 January 2004. The storm can be divided into two phases, first phase up to 1000 UT when interplanetary magnetic field IMF-Bz was highly fluctuating around a small positive value and the second phase after a sudden large southward turning of IMF-Bz at 1030 UT. The first phase produced strong spread-F at Jicamarca, Sao Luis, and Ascension Island and caused complete inhibition of spread-F at Thumba and Waltair in India. It generated weak spread-F at Ho Chi Minh City in Vietnam and strong spread-F at Hainan and Chung Li. The strong spread-F at Hainan and Chung Li were caused by the positive IMF-Bz during the first phase of the storm and not by the negative pulse of IMF-Bz at 1000 UT.  相似文献   

Prediction of Rock Size Distribution in Mine Bench Blasting Using a Novel Ant Colony Optimization-Based Boosted Regression Tree Technique     

Zhang  Shike  Bui  Xuan-Nam  Trung  Nguyen-Thoi  Nguyen  Hoang  Bui  Hoang-Bac 《Natural Resources Research》2020,29(2):867-886

Natural Resources Research - In this paper, we used artificial intelligence (AI) techniques to investigate the relation between the rock size distribution (RSD) and blasting parameters for rock...  相似文献