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Showing papers in "Arabian Journal of Geosciences in 2018"


Journal ArticleDOI
TL;DR: Wang et al. as discussed by the authors conducted a review with the aim of investigating the research background of landslide susceptibility in the world during the period of 2005-2016, and concluded that the recent technological developments in the field of remote sensing, computing technologies and Geographic Information Systems (GIS), the increased data availability, and recent policy developments are important elements for increasing the research interest in landslide susceptibility.
Abstract: Landslides are one of the most important environmental hazards occur naturally or human-induced with large-scale social, economic, and environmental impacts. Landslide susceptibility zoning, which has been widely performed in the last decades, allows identifying spatial prediction of areas of landslides, which could be used for land use planning and land management. The present study was conducted as a review with the aim of investigating the research background of landslide susceptibility in the world during the period of 2005–2016. The results showed that the publication of papers related to landslide susceptibility during the period of investigation has been on the rise, and China has produced a larger number of papers and authors (13% of total). In addition, this article reviews the most popularly used models and the most frequently used input factors. Among different models, the logistic regression has been used as the most common method for assessing landslide susceptibility in 28.4% of the articles, and the slope gradient is considered as the most important conditioning factor in landslide occurrence in 94.2% of the articles. Finally, it is concluded that the recent technological developments in the field of remote sensing, computing technologies and Geographic Information Systems (GIS), the increased data availability, and the awareness has arisen among media and recent policy developments are important elements for increasing the research interest in landslide susceptibility.

150 citations


Journal ArticleDOI
TL;DR: In this paper, the authors summarized the critical factors (pyrolysis temperature, solution pH, dosage of biochar, contact time, co-existed ions, modification/activation, aging process, etc) affecting the overall adsorption efficiency of the biochar.
Abstract: Successful application of low-cost adsorbent like biochar has introduced multidisciplinary areas of science, particularly with respect to remediation of both organic and inorganic contaminants in soil and water. This review briefly consolidates the currently available literature to comprehend the overall adsorption mechanisms of organic and inorganic contaminants through biochar. Generally, biochar produced at low pyrolysis temperature is suitable for the adsorption of inorganic contaminants by following the adsorption mechanisms of electrostatic interaction, precipitation, and ion exchange. However, relatively high pyrolysis temperature favors the adsorption of organic contaminants by increasing the surface area and micropores of biochar along with pore filling and hydrophobic and electrostatic interaction as predominant adsorption mechanisms. This review also summarizes the critical factors (pyrolysis temperature, solution pH, dosage of biochar, contact time, co-existed ions, modification/activation, aging process, etc) affecting the overall adsorption efficiency of the biochar. Overall, further field studies and experimentation are required for the reduction of cost in biochar production and its reuse.

119 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the application of logistic regression model for flood susceptibility mapping in southern Gaza Strip areas, where flood inventory maps were identified using Palestinian Water Authorities data and extensive field surveys.
Abstract: This paper investigates the application of logistic regression model for flood susceptibility mapping in southern Gaza Strip areas. At first, flood inventory maps were identified using Palestinian Water Authorities data and extensive field surveys. A total of 140 flood locations were identified, of which 70% were randomly used for data training and the remaining 30% were used for data validation. In this investigation, six causing flood variables from the spatial database were prepared, which are digital elevation model (DEM), topographic slope, flow accumulation, rainfall, land use/land cover (LULC), and soil type. Then, comprehensive statistical analysis techniques including Pearson’s correlation, multicollinearity, and heteroscedasticity analyses were used, to ensure that the regression assumptions are not violated. The uniqueness of the current study is its inclusiveness of influential causing flood parameters and vigorous statistical analyses that led to accurate flood prediction. Quantitatively, the proposed model is robust with very reasonable accuracy. The prediction and success rates are 76 and 81%, respectively. The practical and unique contribution of this investigation is the generation of flood susceptibility map for the region. This is a very useful tool for the decision makers in the Gaza Strip to reduce human harm and infrastructure losses.

106 citations


Journal ArticleDOI
TL;DR: In this paper, the levels of heavy metal contamination in soils and its effects on human health in the northern Telangana, India were assessed and the index of geo-accumulation (Igeo), ecological risk index (ERI), hazard quotient (HQ), hazard index (HI), cancer risk (CR), and lifetime cancer risk was used to estimate the heavy metal pollution and its consequence to human health.
Abstract: The aim of the present study was to assess the levels of heavy metal contamination in soils and its effects on human health in the northern Telangana, India. Soil samples were collected randomly from 15 sampling stations located in the northern Telangana and analyzed for arsenic (As), chromium (Cr), copper (Cu), zinc (Zn), nickel (Ni), and lead (Pb). The index of geo-accumulation (Igeo), ecological risk index (ERI), hazard quotient (HQ), hazard index (HI), cancer risk (CR), and lifetime cancer risk (LCR) were used to estimate the heavy metal pollution and its consequence to human health. Results indicated that As, Zn, Cu, Pb, and Ni were within recommended limits, while Cr concentration (60 mg/kg) exceeded the maximum recommended limit in 93% of soil samples. The HI values of Cu, Ni, and Zn were all less than the recommended limit of HI = 1, indicating that there were no non-carcinogenic risks from these elements for children and adults. LCR for As and Cr concentrations of the soils was found higher than the acceptable threshold value of 1.0E−04, indicating significant carcinogenic risk due to higher concentration of these metals in the soils of the study region. The chronic daily intake of the metals is of major concern as their cumulative effect could result in several health complications of children and adults in the region. Therefore, necessary precautions should be taken to eradicate the health risk in the study region.

105 citations


Journal ArticleDOI
TL;DR: In this article, an attempt has been made to identify critical zones, which are having a higher vulnerability to the flood in the Vaitarna basin through remote sensing and geospatial approach.
Abstract: Flood is one of the most common natural hazard that take place almost everywhere around the world except the polar regions. Flood damage can be reduced through implementing proper management and policies. Flood is a common hazard in Vaitarna basin, Maharashtra, and occurs once in every 2 to 3 years; it causes severe damage to life and properties. Present days, remote sensing and geographic information system are very comprehensive tools for the assessment of hydrological analysis and hazard management. These tools are also capable to deliver quite an accurate result in a cost- and time-effective manner. Thus, in this paper, an attempt has been made to identify critical zones, which are having a higher vulnerability to the flood in the Vaitarna basin through remote sensing and geospatial approach. Total nine influencing factors, such as elevation, slope, distance from the river, rainfall, flow accumulation, land use, geology, topographic wetness index, and curvature have been assessed individually as well as integrated in GIS software by assigning relative weights through the analytical hierarchy process (AHP) approach. As a result of this study, a final flood map has been prepared and the regions having very high flood potentiality are identified. The resultant map has shown about 20% of the total area in Vaitarna basin is having a very high probability of flood, and these regions are requiring some serious attention of governmental or non-governmental bodies to reduce the flood risk. The analytical hierarchy process (AHP) method proposed in this study is capable to provide an accurate result for flood mapping and can be easily applied to other regions around the world for the management and prevention of the flood hazard.

89 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used a servo-controlled testing system to investigate the fractal characteristics of coal rock fragments under different loading rates and found that most of the coal fragments are irregular wedges and bulks, exhibiting obvious shape characteristics.
Abstract: Rock burst is a serious geological hazard in deep underground mines affecting progress of mining operations. Although rock burst is a complex process, a distribution law of fractal characteristics can explain the rock failure mechanism. Using a servo-controlled testing system, uniaxial cyclic loading tests on coal rock specimens were conducted to investigate the fractal characteristics of the fragments under different loading rates. To comprehensively characterize the coal fragments of different sizes, samples were divided into four groups of different size: particles, fine, medium-size, and coarse fragments. The distribution of the fragments under uniaxial cyclic loading conditions was then investigated based on the theory of fractal geometry, and the relationships between fractal dimensions and loading rates. Under uniaxial cyclic loading and unloading conditions, most of the fragments are irregular wedges and bulks, exhibiting obvious shape characteristics. Under various loading rates, the length-quantity fractal dimensions of the coal fragments ranged from 0.74 to 1.44, the width-quantity fractal dimensions range from 0.44 to 1.65, and the thickness-cumulative mass fractal dimensions range from 1.0 to 1.33. The coal rock’s crushing size-mass fractal dimensions under different loading rates were 2.27, 2.30, 2.32, and 2.35, respectively. Under a small loading rate, the dimension-quantity fractal dimensions are relatively small, suggesting that the coal rock was less crushed, with large fragments differing greatly in length, width, and thickness. The results show that the coal rock fragments exhibit certain shape characteristics after the cyclic loading, like irregular shapes and wedges. Under a larger loading rate, the fragments showed greater fractal dimensions of both size and mass; the coal samples crushed more thoroughly with more uniform fragments in length, width, thickness and mass. The conclusions obtained in this study confirm the classification and fractal characteristics of coal rock fragments by uniaxial cyclic loading conditions in laboratory test and provide the basis for further study on the mechanism of rock burst. This study is helpful for us to make a thorough inquiry the danger degree of rock burst in coal mine by using fractal geometry, understand the effects of methane to coal and the evolution mechanism of cracks, and it can be applied to the research on occurrence mechanism and early warning of rock burst.

87 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examined the efficacy of three machine ensemble classifiers, namely, random forest, rotation forest and AdaBoost, in assessing flood susceptibility in an arid region of southern Iraq.
Abstract: This study examined the efficacy of three machine ensemble classifiers, namely, random forest, rotation forest and AdaBoost, in assessing flood susceptibility in an arid region of southern Iraq. A dataset was created from flooded and non-flooded areas to train and validate the ensemble classifiers using a binary classification scheme (1—flood, 0—non-flood). The prepared dataset was then partitioned into two sets with a 70/30 ratio: 70% (2478 pixels) for training and 30% (1062 pixels) for testing. A total of 10 influential flood factors were selected and prepared based on data availability and a literature review. The selected factors were surface elevation, slope, plain curvature, topographic wetness index, stream power index, distance to rivers, drainage density, lithology, soil and land use/land cover. The information gain ratio was first utilised to explore the predictive abilities of the factors. The predictive performances of the three ensemble models were compared using six statistical measures: sensitivity, specificity, accuracy, kappa, root mean square error and area under the operating characteristics curve. The results revealed that the AdaBoost classifier was the best in terms of the statistical measures, followed by the random forest and rotation forest models. A flood susceptibility map was prepared based on the result of each classifier and classified into five zones: very low, low, moderate, high and very high. For the model with the best performance, i.e., the AdaBoost model, these zones were distributed over an area of 6002 km2 (44%) for the very low–low zone, 2477 km2 (18%) for the moderate zone and 5048 km2 (40%) for the high–very high zones. This study proved the high capabilities of ensemble machine learning classifiers to decipher flood susceptibility zones in an arid region.

78 citations


Journal ArticleDOI
TL;DR: In this article, the authors used fuzzy-analytic hierarchy process (fuzzy-AHP) integrated with GIS to determine potential zones for groundwater in Beysehir Lake Basin.
Abstract: Delineation of the groundwater potential zones is one of the most essential process for the sustainable management of the groundwater sources. However, groundwater studies are quite hard and complex for many regions besides consuming time and cost. This study focused on the groundwater potential mapping in Beysehir Lake Basin. Mainly, fuzzy-analytic hierarchy process (fuzzy-AHP) integrated with GIS was used to determine potential zones for groundwater. Seven parameters, namely lithology, lineament, drainage density, land use, slope, soil type, and rainfall were evaluated and Groundwater Potential Index (GWPI) was calculated using weight and rating coefficients of each parameter. According to obtained results, GWPI varies from 0.07665 to 0.28243 in the basin. The low, moderate, and high groundwater potential classes were determined with quantile classification method. The groundwater potential map demonstrates that the high groundwater potential area is located around the lake shore, in the alluvium and limestone fields because high permeability rates depend on soil type, low slope, karstic structure, and agricultural activities in these regions. In addition, the distribution of the springs confirms with groundwater potential area determined with this study.

70 citations


Journal ArticleDOI
TL;DR: In this paper, a cellular automata (CA) model was applied to simulate the spatial pattern changes of land use/land cover (LULC) in Ravansar district of Iran from 1992 to 2015.
Abstract: Human‐induced land use/land cover (LULC) changes are among the most important processes that shape the dynamics of the earth’s surface. This phenomenon, which is occurring at an astonishing rate, and its consequential environmental impacts have become an important area of research for scientists.Therefore, a wide range of methods and models have been developed to detect and predict these alterations, among which cellular automata (CA) models such as the CA‐Markov model, due to their affinity to geographic information system (GIS) and remote sensing (RS), are appropriate for detailed resolution modelling and simulating dynamic spatial processes. In Iran, the district of Ravansar has undergone severe LULC changes recently, thus to take the necessary precautions, decision‐makers need to predict and determine the extent of these changes. In this study, using spatial analysis methods the LULC changes in Ravansar were investigated from 1992 to 2015. Subsequently, the CA‐Markov model was applied to simulate the spatial pattern changes of LULC until 2030. Our results indicated that from 1992 to 2015, this region has witnessed a noticeable increase in the areas of the built‐up and agricultural lands (both aquatic and non‐aquatic), resulting in the decrease of the gardens, range, and bare lands. The simulated LULC map showed that this trend will continue due to more urbanization and development of agricultural areas.

66 citations


Journal ArticleDOI
TL;DR: A comprehensive review of the development and practice of jet grouting through some fundamental concepts and relevant case studies and a laboratory testing program is performed to investigate the factors affecting the efficacy of the twin grouting system.
Abstract: The jet grouting technique was originally initiated in the UK and progressively developed following the needs for larger geometries, ease of implementation, economic rationality, and better mechanical properties. This paper presents a comprehensive review of the development and practice of jet grouting through some fundamental concepts and relevant case studies. Subsequently, a laboratory testing program is performed to investigate the factors affecting the efficacy of the twin grouting system. The principal objective of this study is to define the suitable conditions for the jet grouting efficacy regarding economic rationality as well as quality control. For the first phase, a particular emphasis is placed on the properties of jet columns, site geological conditions, implementation methods, and the justification of each selected treatment option, while the second phase mainly focuses on the unconfined compressive strength (UCS) tests. It follows that the mono-fluid jet grouting system presents a valuable flexibility in dealing with complex configurations; yet, the double- and triple-fluid systems are more indicated for cases of mass treatments for which large portions of space must be treated and overlapping is fundamentally important for the reliability of the treatment. Furthermore, it was established that the efficacy of the twin-jet method primarily relies on the proper adequacy of some critical parameters, namely, the cement content, the water-cement ratio, and cement slurry-water glass ratio. In spite of some uncertainties inherently related to the technique, the UCS test represents the quintessential laboratory index for evaluating the mechanical properties of grouted elements, deriving jet grouting efficacy and the economics of jet grouts.

61 citations


Journal ArticleDOI
TL;DR: In this article, the interpretation of well log responses such as gamma ray, resistivity, density and neutron logs from six wells under the study area of Krishna-Godavari (K-G) basin is depicted.
Abstract: Well log analysis provides the information on petrophysical properties of reservoir rock and its fluid content. The present study depicts interpretation of well log responses such as gamma ray, resistivity, density and neutron logs from six wells, namely W-1, W-2, W-9, W-12, W-13 and W-14 under the study area of Krishna-Godavari (K-G) basin. The logs have been used primarily for identification of lithology and hydrocarbon-bearing zones. The gamma ray log trend indicates deposition of cleaning upward sediment. Coarsening upward, clayey-silty-sandy bodies have been evidenced from the gamma ray log. Gas-bearing zones are characterised by low gamma ray, high deep resistivity and crossover between neutron and density logs. Total 14 numbers of hydrocarbon-bearing zones are identified from wells W-9, W-12, W-13 and W-14 using conventional log analysis. Crossplotting techniques are adopted for identification of lithology and fluid type using log responses. Crossplots, namely P-impedance vs. S-impedance, P-impedance vs. ratio of P-wave and S-wave velocities (Vp/Vs) and lambda-mu-rho (LMR), have been analysed to discriminate between lithology and fluid types. Vp/Vs vs. P-impedance crossplot is able to detect gas sand, brine sand and shale whereas P-impedance vs. S-impedance crossplot detects shale and sand trends only. LMR technique, i.e. λρ vs. μρ crossplot is able to discriminate gas sand, brine sand, carbonate and shale. The LMR crossplot improves the detectability and sensitivity of fluid types and carbonate lithology over other crossplotting techniques. Petrophysical parameters like volume of shale, effective porosity and water saturation in the hydrocarbon-bearing zones in these wells range from 5 to 37%, from 11 to 36 and from 10 to 50% respectively. The estimated petrophysical parameters and lithology are validated with limited core samples and cutting samples from five wells under the study area.

Journal ArticleDOI
TL;DR: In this paper, the free vibration of functionally graded beams resting on two parameter elastic foundation was examined, and the effects of Winkler-Pasternak type elastic foundation and functionally graded material properties on the values of dimensionless frequency parameter of beams were discussed.
Abstract: In the present study, the free vibration of functionally graded beams resting on two parameter elastic foundation was examined. The properties of the functionally graded materials were presumed to vary continuously along the thickness direction. The foundation medium was assumed to be linear, homogeneous, and isotropic, and it was modeled by the Winkler-Pasternak model with two parameters for describing the reaction of the elastic foundation on the beam. The functionally graded beam was modeled with classical beam theory. The governing equation including the effects of functionally graded material properties, Winkler-Pasternak elastic foundation was solved using separation of variables. The eigenvalues of yielding fundamental equation versus clamped-clamped, clamped-free, clamped-simply supported, and simply supported-simply supported boundary conditions were found. To corroborate the results, comparisons were carried out with available results for homogeneous and functionally graded beams. The effects of Winkler-Pasternak type elastic foundation and functionally graded material properties on the values of dimensionless frequency parameter of beams were discussed. Briefly, it was found that the dimensionless frequency parameters of beam change according to material properties, presence of elastic foundation, and boundary conditions; moreover, the separate effects of these quantities on each other are interesting.

Journal ArticleDOI
TL;DR: In this paper, the authors estimate the unmodelled signals mainly linked to the external magnetic fields and compute residuals from the available day-time and night-time original CHAMP (CHAllenging Minisatellite Payload) satellite data and GRIMM-3 model.
Abstract: Recently, due to more than a decade of magnetic measurements obtained from LEO (low Earth orbit) satellites, more robust global geomagnetic field models have been produced. Generally, these models are based on data selected on specific criteria, as night-side and quiet-time measurements to get the best possible description of the internal contributions and to minimise the ionospheric and magnetospheric effects. Despite recent efforts, the external fields contributions remain poorly modelled and clearly understood. Here, we propose to estimate the unmodelled signals mainly linked to the external magnetic fields. We compute residuals from the available day-time and night-time original CHAMP (CHAllenging Minisatellite Payload) satellite data and GRIMM-3 model. The post-processing of residuals and the residuals distribution for all geomagnetic field components offer us the possibility to investigate some of their specific features, important to be considered when internal field models are computed.

Journal ArticleDOI
TL;DR: In this article, three statistical methods are used for the landslide susceptibility assessment: logistic regression, frequency ratio, and weights of evidence in a GIS platform, and three landslide susceptibility maps were produced using different statistical models.
Abstract: Slope instability phenomena in Souk Ahras region are annually causing a great amount of damage mainly to road infrastructure, water main supply, and buildings. The main problem is that instabilities keep reoccurring despite the remedial measures brought about every time. The fact is there is not only a single factor that is behind these instabilities rather than the interplay of a large variety of factors pertaining to the geological, geomorphological, and hydrological characteristics of the terrain as well as human-related activities. Consequently, a spatial database of ten landslide-related factors were identified and used to assess landslide susceptibility and establish a model capable of predicting landslide prone areas. For this reason, three statistical methods are used for the landslide susceptibility assessment: logistic regression, frequency ratio, and weights of evidence in a GIS platform. A landslide inventory map was established from visual interpretation of satellite images and field survey data. Three landslide susceptibility maps were produced using different statistical models. Each susceptibility map subdivides the study area into five classes of landslide susceptibility: very low, low, moderate, high, and very high. These raster-based susceptibility maps were compared and verified with both training and validating inventory data. The area under the curve values, based on success rate, are between 82.11 and 90.57%, and those based on prediction rate are between 83.14 and 90.91%. The results showed that the logistic regression method is more consistent and reliable than the two other techniques, and it has the best performance among the three statistical methods.

Journal ArticleDOI
TL;DR: In this article, the Gulez formula was used to evaluate the recreational potential of Kastamonu-Pompeiopolis and found that it has a high recreational potential, and therefore, management and planning is needed for trekking, hiking, and the rest of the activities in order to ensure longterm sustainability.
Abstract: Kastamonu-Pompeiopolis is a protected area with historical, natural, and cultural value and has recently increased in popularity. The aim of this study is to ensure the sustainability of natural and cultural resources via an evaluation to reveal the necessary practices and precautions regarding the area’s landscape plan decisions for the ancient city. Maps of Pompeiopolis were created and the Gulez formula (1990) was used to evaluate the city. Based on the data obtained from the area, we have determined that it has a high recreational potential, and hence this study. We find that the untapped recreational potential of Pompeiopolis has yet to be exploited and reached. According to the formula, Pompeiopolis’s recreational potential is 72%, which means it is considered to be an area of high recreational potential. In conclusion, Pompeiopolis has a wealth of ecotourism activities, including historical and cultural tourism, bird watching, wildlife tours, adventure and sports tourism, photography, camping, picnic activities, and cave exploring. However, management and planning is needed for trekking, hiking, and the rest of the activities in order to ensure long-term sustainability.

Journal ArticleDOI
TL;DR: In this article, the authors focused on the extraction of lineaments in Pravara basin, Maharashtra, by using Cartosat Digital Elevation Model (CartoDEM) and ArcGIS and Rockworks software, respectively.
Abstract: Lineaments are the linear or curvilinear geological surface features which reflect the tectonic history, groundwater potential, oil, and mineral resource availability of a given area. In view of the importance of lineaments, the present study is carried out to understand the spatial distribution, orientation, density, and the influence of lineaments on drainage network. The study focuses on the extraction of lineaments in Pravara basin, Maharashtra, by using Cartosat Digital Elevation Model (CartoDEM). The lineaments are extracted and analyzed in ArcGIS and Rockworks software, respectively. Comparative analysis is performed on eight different lineament outputs which are extracted from various azimuth angles to prepare one final lineament map of the study area. Total number of lineaments found in the study area is 709 with the length of 1194.77 km. The western part of the Pravara basin shows higher lineament density as compared to the central and eastern part. Therefore, these areas might be affected by higher structural deformation. Also, this area might have higher groundwater infiltration potential due to the higher density of lineaments as they work as the structural weaknesses and influence the water to infiltrate in sub-surface region. The study has shown that the predominant orientation of lineaments trending to NNW-SSE. About 10% of the total stream length is found to have the influence of lineaments on the drainage network. More control of lineaments is observed in the source region of the drainage, where mostly first-order streams are found. Apart from the significant findings, this study has been generated a detailed structural information over the study area and the output could be applied for future planning and management of the water resources, tectonic evolution, and in other fields of geosciences.

Journal ArticleDOI
TL;DR: In this article, the authors tried to understand the soil erosion characteristics in a tropical plateau fringe region by the use of Revised Universal Soil Loss Equation (RUSLE) for soil loss estimation.
Abstract: This paper tries to understand the soil erosion characteristics in a tropical plateau fringe region by the use of Revised Universal Soil Loss Equation (RUSLE). Soil loss estimation is an important phenomenon to understand the land degradation. An integrated method needs to be adopted in tropical plateau fringe region to estimate the soil loss. RUSLE has been adopted for the present study. The river in the basin under consideration sees its origin from a plateau top region and flows through the plateau fringe region of eastern Chotanagpur plateau, India. The present study area reflects undulated plateau fringe landform with gently sloping dissected plateau topography. The different factors like, rainfall erosivity factor (R), soil erodibility factor (K), topographic factor (LS), crop and management factor (C), and support and practice factor (P) have been enumerated using field and remote sensing data. Each factors result has also been verified with previous literature. All factors have been multiplied in GIS environment to estimate soil loss. High-magnitude soil loss region (> 10 t ha−1 year−1) covers 4.88% of the total area and extends up to the upper reaches of the watershed. Topographic and soil factors best represent this loss. Low-magnitude soil loss region (< 2.5 t ha−1 year−1) in the lower reaches of the watershed is a result of successful land management activity. Soil erosion is dominated process of land degradation in the upper reaches of the watershed and estimation of soil loss is an important input for land-use land-cover management. The study also inferred that RUSLE soil erosion model could be effectively used in tropical plateau fringe environment.

Journal ArticleDOI
TL;DR: In this article, both experimental and numerical methods are employed to investigate the coal drawing from thick steep seam with longwall top coal caving mining, and a series of analyses are performed to investigate features of the drawing body, the distribution of top coal recovery ratio and the shape of the rock flow under steep conditions.
Abstract: Steep coal seam mining activities will frequently occur during the next few decades in China. In this study, both experimental and numerical methods are employed to investigate the coal drawing from thick steep seam with longwall top coal caving mining. A series of analyses is performed to investigate the features of the drawing body, the distribution of top coal recovery ratio and the shape of the rock flow under steep conditions. The results indicate that the drawing body of top coal develops prior to upper side of the panel face obviously, and the top coal in the central part of the panel has a higher recovery ratio than that in the lower and upper parts in steep coal seam with caving mining method. The flow paths of the fragmented top coal are nearly straight lines moving towards the drawing window, and the fastest path maintains a constant angle with the plumb line. The spatial shape of the rock flow indicates “bidirectional asymmetry,” which results from the presence of the shield beam and dip angle of the coal seam; thus, this is the root cause of the appearance of the drawing body’s prior development towards the upper side of the panel. The field observation data indicates the same distribution of top coal recovery as that in the physical experiment and numerical simulation. Furthermore, suggested measurements are proposed to improve top coal recovery in steep seam mining based on the engineering practice of Dayuan coal mine.

Journal ArticleDOI
TL;DR: In this paper, the authors focused on spatial rainfall variability and drought assessment in Khyber Pakhtunkhwa province of Pakistan using Standardized Precipitation Index (SPI) Various indices like standard deviation, skewness, and kurtosis were calculated from annual rainfall of 15 meteorological stations during period of 1971-2015 Mann-Kendall technique was applied to both 1-month and 12-month SPIs for trend detection.
Abstract: High rainfall variation creates problems of floods and droughts in any region of the world This study focuses on spatial rainfall variability and drought assessment in Khyber Pakhtunkhwa province of Pakistan using Standardized Precipitation Index (SPI) Various indices like standard deviation, skewness, and kurtosis were calculated from annual rainfall of 15 meteorological stations during period of 1971–2015 Mann-Kendall technique was applied to both 1-month and 12-month SPIs for trend detection All stations showed a positive skewness except Balakot The highest variability was found in Parachinar and Balakot The results of 12-month SPI showed two distinct dry periods, ie, 1984 to 1989 and 1998 to 2002 Mann-Kendall trend test for 1-month SPI reveals more significant positive trend in Parachinar and there was variation in the results of other met-stations In almost all the met-stations, December was found the driest month as the p values were found negative except in Parachinar Additionally, the result of 12-month SPI indicated more significant positive trend in Parachinar, whereas more significant negative trend in Balakot met-stations has been recorded

Journal ArticleDOI
TL;DR: In this article, daily rainfall-runoff modeling was done using co-active neuro-fuzzy inference system (CANFIS) and multi-layer perceptron neural network (MLPNN) approaches in the hilly Naula watershed of Ramganga River in Uttarakhand, India.
Abstract: In this study, daily rainfall-runoff modeling was done using co-active neuro-fuzzy inference system (CANFIS) and multi-layer perceptron neural network (MLPNN) approaches in the hilly Naula watershed of Ramganga River in Uttarakhand, India. The daily observed rainfall and runoff data from June 1, 2000, to October 31, 2004, were used for training and testing of the applied models. Before starting the modeling process, the gamma test (GT) was used to select the best combination of input variables for each model. The simulated values of runoff from CANFIS and MLPNN models were compared with the observed ones with respect to root mean squared error (RMSE), Nash-Sutcliffe efficiency (CE), Pearson correlation coefficient (PCC). This study provides a conclusive evidence that the CANFIS shows better accuracy than the MLPNN models. Therefore, according to the best fitting CANFIS-10 model, the runoff of the present day depends on rainfall and runoff of current and previous 2 days for the studied area.

Journal ArticleDOI
TL;DR: In this paper, the authors assessed the Yarmouk Basin (YB), in northern Jordan, using the Standardized Precipitation Index (SPI), the standardized Water-Level Index (SWI), and the Percent Departure from Normal rainfall (PDNimd) during the years 1993-2014.
Abstract: This article assesses drought status in the Yarmouk Basin (YB), in northern Jordan, using the Standardized Precipitation Index (SPI), the Standardized Water-Level Index (SWI), and the Percent Departure from Normal rainfall (PDNimd) during the years 1993–2014. The results showed that the YB suffers from frequent and irregular periods of drought as variations in drought intensity and frequency have been observed. The SPI results revealed that the highest drought magnitude of − 2.34 appeared at Nuaimeh rainfall station in 1991. This station has also experienced severe drought particularly in years 1995, 1999, 2005, and 2012 with SPI values ranging from − 1.51 to − 1.59. Some other rainfall stations such as Baqura, Ibbin, Khanasiri, Kharja, Mafraq police, Ramtha, Turra, and Umm Qais have also suffered several periods of drought mostly in 1993. The SWI results show the highest extreme drought events in 2001 in Souf well while other extreme drought periods were observed at Wadi Elyabis well in 1994 and at Mafraq well in 1995. As compared to SPI maps, our SWI maps reflect severe and extreme drought events in most years, negatively impacting the groundwater levels in the study area.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the groundwater hydrochemistry (pH, EC, TDS, TH, SO42−, PO43−, NO3−, Na2+, K+, Mg2+, Ca2+, F− and Cl−) of 76 representative sites and analyzed for different parameters.
Abstract: This study investigates the groundwater hydrochemistry (pH, EC, TDS, TH, SO42−, PO43−, NO3−, Na2+, K+, Mg2+, Ca2+, F− and Cl−) of intensively cultivated belt of Malwa Punjab, India. The groundwater was collected from 76 representative sites and analysed for different parameters. Results suggested that in the majority of locations, the TH, TDS, K+, Mg2+, Ca2+ and Cl− were within the limit as decided by Bureau of Indian Standards (BIS) for drinking purposes. The proportion of SO42− and PO43− was SO42− > PO43− mg/L in the majority of sampling locations. The Na+ was recorded in a high range 26.05 to 735.5 mg/L indicating Na-rich groundwater in this area. Fluoride ranged 1.59 to 5.07 mg/L in this region, higher than the than permissible range (1.5 mg/L). The NO3− was prominent anthropogenic mineral in groundwater. The suitability of groundwater for drinking and irrigation purposes was also calculated. The water quality index (WQI) suggests that about 80.3% sites have low quality water, unsuitable for drinking purposes. The suitability of groundwater for irrigation purposes was evaluated using SAR and LSI value, which revealed that in the majority of areas, the groundwater is unfit for surface irrigations. This study revealed that overall groundwater of Malwa Punjab is not suitable for drinking as well as agricultural purposes due to excess of some natural and anthropogenic chemicals. The long-term uses of such water could pose serious soil and human health issues in this regions.

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TL;DR: In this article, the authors analyzed the mechanical properties of granite as a function of temperature and found that the tensile strength and fracture toughness tend to decrease with temperature, while variations in the compressive strength and elastic modulus demonstrated decreasing trends when the heating temperature exceeded 400°C.
Abstract: Variations in the mechanical properties (compressive strength, elastic modulus, tensile strength, and fracture toughness) of granite were analyzed as functions of temperature. It was found that above 200 °C, tensile strength and fracture toughness tended to decrease with temperature, while variations in the compressive strength and elastic modulus demonstrated decreasing trends when the heating temperature exceeded 400 °C. The temperature ranges of room temperature—200 and above 600 °C—corresponded to an undamaged state and strongly/completely damaged state, respectively. It is suggested that 400 °C might be a critical threshold of thermal damage to granite. Based on results of statistical tests, a sharp decrease in mechanical properties can be recognized, accompanied by a drastic growth in peaking strain and acoustic emission rate. This phenomenon may be associated with the α/β phase transition of quartz.

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TL;DR: In this article, an ITA-change boxes (CB) approach is proposed, taking into account quantitative changes with increasing or decreasing trends of the two half-time series obtained from the data given the periodicity of the hydro-meteorological data, the data group is used to obtain two halftime series instead of the data This approach assists to make more detailed interpretations about trend possibilities within a given time series.
Abstract: Systematic and random changes occur in any hydro-meteorological record and have significant effects on human activities on time and space scales Although it is almost impossible to forecast the future behavior of any natural event accurately, researchers can identify trend on systematic variations and seasonality rather accurately with random residual parts On the other hand, the role of trend is very significant in climate change studies and the Mann-Kendall test is the most employed method for trend identification However, this method requires restrictive assumptions such as the data length, normality, and serial independence Recently, innovative trend analysis (ITA) method is suggested for detailed trend determination and classification interpretations in a given time series without restrictive assumptions In this study, an ITA-change boxes (CB) approach is proposed, taking into account quantitative changes with increasing or decreasing trends of the two half-time series obtained from the data Given the periodicity of the hydro-meteorological data, the data group is used to obtain two half-time series instead of the data This allows the researcher to numerically observe changes in trends beyond visualization This approach assists to make more detailed interpretations about trend possibilities within a given time series The applications of the proposed approach are presented for daily temperature and monthly rainfall and discharge records from Turkey, UK, and the USA

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TL;DR: In this paper, trends of rainfall of the Central India were evaluated in monthly, seasonal, and annual time scales using the Revised Mann-Kendall (RMK) test, Sen's slope estimator, and innovative trend method (ITM).
Abstract: In the present study, trends of rainfall of the Central India were evaluated in monthly, seasonal, and annual time scales using the Revised Mann-Kendall (RMK) test, Sen’s slope estimator, and innovative trend method (ITM). For this purpose, the monthly rainfall data for 20 stations in Madhya Pradesh (MP) and Chhattisgarh (CG) states in Central India during 1901–2010 was used. The Sen’s slope estimator was utilized for calculating the slope of rainfall trend line. Based on the obtained results of RMK test, there is no significant trend in the stations for the January and October months. The results also showed that for MP, two out of 15 considered stations indicate significant annual trend, while the CG has four out of five stations with significant trend. The results of applying ITM test indicated that most of the stations have decreasing trends in annual (16 stations), summer (16 stations), and monsoon (11 stations) seasons, while the winter (12 stations) and post monsoon (11 stations) seasons generally show increasing trend. Unlike the RMK, the ITM shows significant increasing trend in rainfall of November and December months. The finding of current study can be used for irrigation and water resource management purpose over the Central India.

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TL;DR: In this article, a Landslide Susceptibility Assessment Model (LSAM) was developed for a corridor of 27 km along NH 10 in the East Sikkim in India.
Abstract: In hilly areas, highway projects can be a cause of landslides as well as an element of vulnerability due to landslides. Hence, landslide susceptibility mapping of highway corridors can substantially mitigate loss of life and property. For this, a Landslide Susceptibility Assessment Model (LSAM) was developed for a corridor of 27 km along NH 10 in the East Sikkim. Landslide inducing factors viz. Aspect, Distance from Fault, Distance from Road, Drainage Density, Land use and Land cover, Lithology, Plan Curvature, Rainfall, Slope, Soil Depth, and Soil Texture were considered for the study. Results show that areas in proximity to the highway and areas with steeper slope had a higher landslide susceptibility than otherwise. Spatial explicit sensitivity analysis indicated that LSAM was sensitive to distance from the highway and slope. Vehicle vulnerability assessment of base year and horizon years showed that vulnerability increased through time. LSAM is appropriate for hazard mitigation for areas with poor historical data on landslides.

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TL;DR: In this article, a review aimed to summarize the impact of biochar application on soil physical properties, discuss the factors and mechanisms influencing biochar performance, and identify future research priorities.
Abstract: Biochar, a solid product produced from biomass pyrolysis under low oxygen conditions, has gained wide acknowledgment in its usage as a means for carbon sequestration as well as improving the soil chemical and physical properties of the soil. Although the effects of biochar application on chemical characteristics and fertility of soils have been intensively investigated, there is little information on its role in improving soil physical characteristics. Therefore, this review aimed to (i) summarize the impact of biochar application on soil physical properties, (ii) discuss the factors and mechanisms influencing biochar performance on soil physical properties, and (iii) identify future research priorities. This review concluded that the improved impact of biochar application on soil physical characteristics is dependent upon feedstock and pyrolyetic conditions of biochars, application rate of biochar, biochar particle size, and soil type and texture. Pyrolysis temperature is the main factor controlling biochar properties such as porosity and surface area, which reflect their effects on soil physical characteristics. For the same feedstock, the temperature will control the properties of resulting biochars. But, the biochar properties greatly depend on the properties of feedstock. For example, manure-derived biochars contain a large amount of ash, but biochars from cellulose-lignin biomass mainly consist of the carbon fraction. Despite the profound effect of biochar in improving the physical properties of soil, the economic impact of its implementation in large-scale farming has not been established. Therefore, there is need for its economic evaluation.

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TL;DR: In this article, the spatial and temporal patterns of drought hazard and risk in Semnan province, Iran were determined using kriging interpolation and natural break methods by ArcGIS 9.3 software.
Abstract: This study attempts to determine the spatial and temporal patterns of drought hazard and risk in Semnan province, Iran. Drought risk assessment has been conducted in eight counties of Semnan province using a conceptual framework which emphasizes on the combined role of hazard and vulnerability in defining droughts. The standardized precipitation index (SPI) at synoptic stations at 3 and 12-month time step for period 1985–2011 were used to provide drought hazard index (DHI) map using kriging interpolation and natural break methods by ArcGIS 9.3 software. Eight obtainable/quantifiable socioeconomic and physical indicators including population density, rural ratio, agricultural occupation, irrigated land, food production, and municipal, industrial, and agricultural water consumption were used to provide the map of drought vulnerability index (DVI). Finally, the map of drought risk index (DRI) was provided through the integration of DHI and DVI maps. The overall results showed that at 3-month timescale Shahroud and Damghan and at 12-month timescale Shahroud, Damghan, and Semnan are the most susceptible regions to drought in central Iran. Therefore, consideration of virtual water, cultivation of products with less water requirement and use of appropriate irrigation methods can be two important factors in water demand management which should be addressed by water resource managers.

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TL;DR: In this article, the authors evaluated four most commonly used distribution methods, i.e., Generalized Extreme Value (GEV), Log Pearson 3 (LP3), Gumbel Max, and Normal for the flood frequency and estimation of flood recurrence.
Abstract: In Pakistan, floods are among the most devastating and recurring natural hazards. Flood hazard assessment requires flood event magnitude and probability of occurrence. Flood frequency analysis is the most common technique used for the at-site estimation of flood recurrence magnitude. This paper evaluates four most commonly used distribution methods, i.e., Generalized Extreme Value (GEV), Log Pearson 3 (LP3), Gumbel Max, and Normal for the flood frequency and estimation of flood recurrence. Different hydrological stations data namely Khwazakhela, Chakdarra, Panjkora, and Munda Headwork located at Swat river was taken from Provincial Irrigation Department, Khyber Pakhtunkhwa. The analysis is done for 5-, 10-, 25-, 50-, and 100-year return periods by using annual maximum discharge data from 1980 to 2016 (37 yr). Three goodness-of-fit tests were applied to the fitted distributions, i.e., Kolmogorov–Smirnov, Anderson–Darling, and Chi-squared at 5% significance level. Results indicate that LP3 and GEV were ranked top two distributions at all locations while Gumbel Max and Normal were the least fitted having rank 3 and 4, respectively. Based on the goodness-of-fit ranking, LP3 was selected for the estimation of flood magnitude and return periods at Khwazakhela. Designed hydrographs based on probabilistic approach and flood 2010 hydrograph are presented for flood simulation.

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TL;DR: In this article, two cores of sediments, named NR and EB, were collected in the Simbock Lake (Mefou watershed, Yaounde) to assess their provenance and the degree of heavy metal pollution based on mineralogical and geochemical data.
Abstract: Two cores of sediments, named NR and EB, were collected in the Simbock Lake (Mefou watershed, Yaounde) to assess their provenance and the degree of heavy metal pollution based on mineralogical and geochemical data. The sediments are sandy, sand-clayey to clayey, and yellowish brown to greenish brown, and with high amounts of organic matter (average value of TOC is 1.95%). The sediments are mainly composed of quartz, kaolinite, accessory goethite, smectite, rutile, feldspars, illite, gibbsite, and interstratified illite-vermiculite. Fourier transform infrared (FT-IR) spectroscopy shows that kaolinite is less crystallized in the NR core than in the EB core. The Index of Compositional Variability (ICV), Chemical Index of Alteration (CIA), Plagioclase Index of Alteration (PIA), and the Rb/Sr and K2O/Rb ratios indicate a high weathering intensity in the source area. These sediments have low contents in Al2O3, Fe2O3, Na2O, K2O, MgO, and CaO as well as high values in SiO2, P2O5, TiO2, and MnO relative to the upper continental crust. The concentrations of Cr, V, Ba, and Zr are higher in the NR core than those in EB. The total rare earth element (REE) content varies between 78 and 405 ppm. The light REE are abundant (LREE/HREE ~ 18–59; avg. = 25.61). The chondrite-normalized REE patterns exhibit (i) negative Eu anomaly (Eu/Eu* ~ 0.38–0.62; avg. = 0.5), (ii) slight positive Ce anomaly (Ce/Ce* ~ 1.11–1.34; avg. = 1.11), and (iii) high REE fractionation ((La/Yb)N ~ 12.3–51.75; avg. = 25.61). The enrichment factor (EF) shows that the Mefou watershed through the Simbock Lake sediments is slightly polluted by the agricultural and urban activities.