ALBERT

Description: 〈h3〉Abstract〈/h3〉 〈p〉Based on field sample collections, wind tunnel experiments, and statistical analyses, the spatial differences of geochemical characteristics of dust aerosol availability originating from different landscapes in the Tarim Basin, Qaidam Basin, and Ala Shan Plateau of northwestern China were evaluated. Experiments and statistical analysis results showed that there are many differences in the geochemical characteristics of dust aerosol availability originating from above regions. Riverbeds, wadis and gobi deserts, and interdunes are the major landscapes for element emissions of dust aerosols in the Qaidam Basin, Ala Shan Plateau, and Tarim Basin, respectively. Among them, more than 60% of the elements such as Ti, Cr, Rb, Y, Nb, Ce, Nd, Pb, and Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 in dust aerosol availability that originated from the Ala Shan Plateau and the Tarim Basin may play an important role in the element emissions in coarse fractions. Variations in the geochemical characteristics of dust aerosol availability caused by landscape and regional differences may play an important role in loess compositions and in past climate reconstructions that used post-depositional eolian sediments as a proxy.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In order to evaluate the intensity of the coal’s bursting liability scientifically and accurately, the index relevance problems existing in the current classification methods were focused on, and the Mahalanobis distance discriminant analysis (DDA) method was introduced on the basis of establishing a measured database with the large sample of the coal’s bursting liability. Besides, the DDA model of coal’s bursting liability classification was also established. Then, with the duration of dynamic fracture, elastic strain energy index, bursting energy index, and uniaxial compressive strength selected as evaluation indicators, three grade-discrimination functions of the bursting liability were established through training the data of 95 groups of bursting liability of different coal seams that were collected extensively. After training, the accuracy rate of the DDA model reached 96%. The results of the application of DDA model to the classification of coal samples from 10 coal mines exhibited remarkable agreement with the actual situation, which also solved the difficult problem that the fuzzy comprehensive evaluation method could not distinguish 8 kinds of samples. Its application to the engineering project shows that the classification result of coal’s bursting liability based on the DDA method is both accurate and easy to calculate, and the DDA model has good engineering application prospect.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In estuaries, the mineral distribution in the top sediment layer results from the combined effect of fluvial and coastal inputs and may present seasonal patterns owing to forcing, e.g., floods, storms, waves, and tides. Our main goal was to study the estuarine sedimentological components, including textural and geochemical parameters, in order to characterize the seasonal and spatial dynamics of subtidal and intertidal sediments in a highly energetic temperate estuary (River Lima, NW Portugal). Subtidal sediments were usually anoxic within the middle estuary and presented higher amounts of clay and silt than intertidal sediments. Oxygen, silicon, carbon, aluminum, and potassium were the most abundant elements. The amount of silicon and carbon was related to the clay and silt content of the sediments. The mineralogical composition of sediments reflected the lithology of the watershed, with the most representative minerals being quartz, microcline (k-alkaloid feldspar), and albite (plagioclase), in line with the results obtained in the elementary characterization. The lower stretches were particularly rich in iron silicates and anatase. No clear seasonal variation was found for sediment elemental and mineralogical compositions. Factor analysis explained 80% of the elemental origin, being 33% related to terrigenous origin, 24% to marine sediments, and 15% to anthropogenic inputs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Geological structure is an important factor to explore the underground geological conditions for hydrogeological purpose. Borehole density has great influence on the accuracy and application of geological model. In this paper, Transition Probability Geostatistical Software (T-PROGS) has been used to simulate the four facies distribution of West Liao River Plain. And a quantitative uncertainty model of entropy method is introduced. For getting a reliable geological model with as few as the boreholes, two parts have been given. One is the vertical lithologic variability analysis, and the other is the model correct rate and uncertainty analysis. In geological modeling, the borehole data is too sparse to characterize the lateral heterogeneity, so the actual profiles are added. At last, many equal probability realizations of the geological model using 350 boreholes are built. Depending on the model calibration, uncertainty analysis and simulated profile comparison, the geological models are reliable. Thus, for the simple and single stratigraphy study area without complex fault structures and graben structures of several thousands to tens of thousands of square kilometer scale, establishing a reliable geological structure model requires one borehole at least within an average area of 120.81 km〈sup〉2〈/sup〉. It is of great significance for decision maker to save manpower and material resources. And we present a workflow to build a 3D Markov chain using boreholes and actual profiles and develop a reliable geological model.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Changes in cyclones in a region may lead to variations in the precipitation conditions of that region. The current study aimed at examining changes in the frequency of cyclones affecting precipitation in the Rood Zard basin, Iran, during 1976 to 2014. To this end, 1000 hPa maps of NCEP/NCAR and the daily precipitation data of 16 stations located in the basin of the Rood Zard were adopted. The results showed that the frequency of cyclones, their consequent precipitation, and the overall amount of cyclonic precipitation experienced a declining trend over the abovementioned period. The findings of the present study are in line with those of previous ones conducted on other areas in the Northern Hemisphere. Following the examination of mean differences in the cyclone frequency during the understudy period, a significant jump was also observed which tends to delay cyclones’ activities compared with those accruing in the previous years. Further, it was discovered that the seasons of cyclonic precipitation became shorter over recent years. The investigation into these changes can be attributed to climate change discussed in a bulk of previous studies. The existing cycles in the frequency of cyclones and cyclonic precipitation showed the presence of similar (3 and 4.6 years) cycles in both factors. Experts in the field have attributed these short-term cycles to quasi-biennial oscillation (QBO) in the troposphere, ENSO, and similar phenomena taking place frequently in climate change context.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The spatial mapping of flood menace extents is crucial for the effective and competent enactment of risk-lessening strategy. We focused on geographical pattern and variation in flood-affected villages in Bongaon sadar sub-division, West Bengal, India, during the period between 1996 and 2016. To appraise the indigenous smoothing and dissimilarity of flood-affected/non-affected villages, GIS-based Voronoi statistics were used. Inverse distance weighting (IDW) is used to interpolate and predict the pattern of flood-affected/non-affected zones across the sub-division. Moran’s 〈em〉I〈/em〉 index statistics was considered to appraise spatial auto-correlation among the flood affected and non-affected villages. Getis-OrdGi*(d) statistics was employed to recognize the flood hotspot and cold spot areas within the study site. The higher magnitude of Moran’s 〈em〉I〈/em〉 was calculated as 1999–2001, 2004, 2011, 2013, 2015, and 2016. The high 〈em〉Z〈/em〉 score was recorded in 1996–1999, 2001–2003, 2011, 2013, and 2014 indicated a spatial clustering of flood-affected villages. The predictive map derived through IDW showed that 7.76% (64.59 km〈sup〉2〈/sup〉) area comes under very high threat zones of flood, followed by 16.27% as high risk, 24.49% as medium risk, 23.97% as low risk, and 27.51% as very low risk. This study determines the solicitation of GIS-based prophecy for the impost of revelation mapping, so as to define the latitudinal extent and frequency of areas where most affected villages are located and potential risk areas.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The using of processed ASTER images and ASTER-GDEM (Advanced Spaceborne Thermal Emission and Reflection Radiometer-global digital elevation model) supplemented by extensive geological field work and spectral measurements of field samples enabled the creating of a new geological map of Gasus area. SVM (Support Vector Machine) method obtained 86% as overall accuracy of the classification and was verified by previous published maps and field verifications. Structure lineaments were automatically extracted and directional analysis of the automatically extracted lineament maps showing that the major trend of the lineaments are NW-SE and NNW-SSE, while NNE-SSW and NE-SW trends can also be recognized but in a less significant order. These trends are compatible and corresponding to the field verification.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Hydraulic fracturing technologies revolutionize the way petroleum industries drill the conventional and unconventional formations by the purpose for oil recovery enhancement. Multi-criteria decision-making (MCDM) methods are always considered as the preferable techniques in organizational and industrial operational performances that some of them are being widely administered for numerous purposes. The objective of this comprehensive study is to conduct an investigation about the considerable influence of five important criteria on the hydraulic fracturing techniques and select the best technology regarding enhancing oil recovery factor. Fuzzy Analytic Hierarchy Process (FAHP) and Fuzzy Technique for Order Preference by Similarity to Ideal Solution (FTOPSIS) analyses are applied to compare each criterion. Consequently, among the five fundamental criteria for selecting and operating hydraulic fracturing, in situ stress-strain with the score weight of 0.421 is the most important selectivity criteria. Furthermore, after analyzing the results derived from FAHP and FTOPSIS methods, hydra-jet fracturing and zipper fracturing techniques with the normalized weights of 0.186 and 0.194, and relative closeness coefficients of 0.69 with a 0.66 are considered respectively as the best and optimum techniques of hydraulic fracturing. Last but not least, the cavitation hydro-vibration fracturing and explosive fracturing are the least preferable methods among hydraulic fracturing techniques.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Groundwater hazard rating systems are generally based on source-pathway-receptor approach. This study determines the response of rating system to the variations in subsurface conditions (generally designated as pathway component). Besides, the study also investigates the ability of the rating systems to respond to the changes in other components too (i.e., source and receptor components). For the purpose, three groups of sites with various combinations of site conditions, that may be encountered in the field, are employed, e.g., a smaller site located in sandy soil with receptors all around it using groundwater or a larger site having a thick clay layer underneath it and the receptors in vicinity using groundwater for drinking. For the analysis, four sets of corresponding rating scores are determined in this study from the selected eleven rating systems (ten earlier rating systems and mGW-HARS, a recently developed system). The investigation shows that mGW-HARAS performs the best for the three sets; for the remaining one set, the performance of mGW-HARAS is marginally lower than its predecessor, GW-HARAS. The sensitivity analysis of the selected rating systems with respect to four critical pathway parameters depicts that mGW-HARAS is sensitive to all the four parameters and has the highest sensitivity to soil permeability, i.e., 83% amongst all the selected rating systems. When these rating systems are applied to ten waste dumps from Indian cities, only one system, i.e., mGW-HARAS, is able to categorize these waste dumps in four hazard categories and responds suitably to the subsurface conditions encountered at these waste dumps.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A clear understanding of pore structure of tight oil reservoirs is essential for reservoir evaluation and enhanced oil recovery. This paper presents a multiscale characterization method using a combination of pressure-controlled porosimetry (PCP), micro-computed tomography (micro-CT), and scanning electron microscopy (SEM). Four tight sandstone samples from Chang 7 Formation in the Ordos Basin were collected for petrophysical characterization. Pore-throat size distributions (PTSDs) for these samples were measured via PCP. A high-resolution micro-CT scan (1 μm/pixel) was used to acquire 3D volumetric images of small core plugs to evaluate pore connectivity of these samples. Additionally, high-resolution digital images were obtained through SEM to identify different pore types. SEM analysis shows that pores in tight sandstones could be classified into four types, i.e., residual interparticle pores, grain dissolution pores, clay pores, and micro-fractures. Residual interparticle pores are often coated by fibrous illite and chlorite. Grain dissolution pores are mainly deduced from the dissolution of grain minerals, among them the feldspar dissolution pore is the primary type. According to the PCP experiments, these samples exhibit multiscale pore structures with a wide range of PTSD from 9.2 nm to 500 μm dominated by nanopores. Average mercury intrusion saturation and permeability contribution value of the dominating nanopores are 63.61% and 80%, respectively. Given the unresolved nanopores, CT images were segmented into three phases, including pore space, grain phase, and clay minerals. The results of connectivity analysis demonstrate that macroscopic pores are mostly connected by clay phases, implying that nanopores provide the critical flow paths. This novel multiscale characterization approach provides us a better understanding of complex pore structures of tight sandstones.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Zirku salt plug is one of eleven emergent salt plugs in the southern Arabian Gulf. Its diapiric core consists of the Late Neoproterozoic–Early Cambrian ‘Hormuz Series’, which are unconformably overlain by ‘post-Hormuz’ calcarenite and breccia. The lithological and sedimentological characteristics of the calcarenite and breccia indicate that they were deposited in a beach and adjacent intertidal flats. It is suggested on stratigraphic grounds and the consideration of previous works that the ‘post-Hormuz’ deposits may be considered Pleistocene–Holocene in age. Diapirism affected the Pleistocene–Holocene deposits and produced mini-diapirs, intrusion and piercement structures, extruded gypsum flows, clastic dykes and diapiric uplift shown by elevated marine terraces and tidal notches. The elevated terraces and notches record sea-level high stands, uplift rates and sea-level fluctuations during the late Quaternary. The calculated rate of uplift of the Zirku salt plug during the period between 128 ka and 11 ka, is nearly constant at 1.05 mm/yr. Periods of transgressions and regressions were inferred from the late Quaternary sea-level curves. In the field, transgression is marked by onlap and the filling up of wadi channels, and regression by producing a new lower base level of wadis and the occurrence of gypcrete interbedded with calcarenite.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In an attempt to investigate the effect of different saturation degrees and micro-pore characteristics on longitudinal wave velocity, the present study selects two groups of sandstones with different micro-pore structure characteristics as research objects. In view of the different degrees of saturation of the samples, improved acoustic emission is employed to measure longitudinal wave velocity and a comprehensive analysis is conducted on the variation of longitudinal wave velocity. The test results show that the longitudinal wave velocity of the sample with diverse porous structure, at different saturation levels, manifests itself in three stages. At the saturation ratio of 0–30%, the wave velocity of the sandstone samples presents an increasing tendency, while there is a slight change given for the saturation ratio of 30–70%, first declining and then slowly increasing. In the third stage, the velocity significantly increases with the saturation ratio of 70–100%. Regarding the samples with a single porous structure, the measured longitudinal wave velocity presents two stages. When the saturation ratio is below 75%, the longitudinal wave velocity decreases slowly with the increase of saturation degree, while there is a sharp increase of the velocity as the saturation ratio increases when the ratio exceeds 75%. Based on the capillary model and the test results of the samples with a single pore structure, a relationship is established between the micro-pore structure characteristics and the macroscopic longitudinal wave velocity of the samples at different water saturation degrees, and the longitudinal wave velocity displays a satisfied consistency with that of the samples with diverse pore structure.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Dust properties are playing a major role in visibility reduction during dust storms. To evaluate the visibility variations in the United Arab Emirates (UAE), data collected at eight stations from 2010 to 2017 was analyzed. The mean annual visibility ranged from 8291 to 9295 with a 7-year overall average visual range of 8.98 km. Results show increasing occurrences in mild to severe dust storms with subsequent progressive decreasing in the mean annual visibility value. Reduction in the annual mean visibility was mainly noted in the central and some northeastern parts of the UAE. Under winter conditions, degradation of visibility extends to Abu Dhabi and other central Emirates. The dust storms occurred at greater frequencies when the wind speed exceeded 15 notes, with a visibility of less than 3000 m.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Ghawar is the largest and most prolific oil field in the world. Yet, no digital geological models or synthetic seismic data of this important field are publicly available for testing algorithms to image, analyze, and understand its complex and interesting attributes. We construct a 2D viscoelastic model of the Ghawar field and calculate a corresponding multi-component synthetic seismic data set. The P-wave velocities and densities of the entire stratigraphic column from pre-Cambrian basement to present-day sediments were compiled from public sources. The S-wave velocities were calculated from the P-wave velocities using empirical 〈em〉V〈/em〉〈sub〉S〈/sub〉–〈em〉V〈/em〉〈sub〉P〈/sub〉 relations established from well logs. An empirical formula was also used to estimate the P-wave and S-wave quality factors from the P-wave and S-wave velocities, respectively. Vertical and horizontal components of viscoelastic seismic shot records were generated using a finite-difference algorithm accurate to the 4th order in space and 2nd order in time. We share the models and seismic data sets publicly hoping that this will motivate interested researchers to test their research ideas, which in turn will help advance the leading edge in hydrocarbon exploration seismology. Finally, we encourage researchers, who will use the models and data sets, to contribute to the geoscience community by sharing their results publicly as well.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Water quality of Chilika lagoon was assessed for pre- and post-monsoon seasons. A marked spatial and temporal variability in the water quality was observed in this study. Principal component analysis (PCA) reveals the influence of salinity, anthropogenic factors, as well as vegetation on the water quality. The higher concentration of nitrate (NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉) and phosphate (PO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉) in certain pockets of the lagoon water was due to the prevalence of agricultural, municipal, and domestic waste. A positive correlation between PO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉 and DSi indicates their terrigenous input from freshwater influx. Cyclone 〈em〉Phailin〈/em〉 had profound impact on several water quality parameters. pH, dissolved oxygen (DO), and dissolved inorganic carbon (DIC) are governed largely by the presence of macrophytes. The impact of severe cyclone 〈em〉Phailin〈/em〉 can be assessed from the very low salinity values persisting in the lagoon even 2.5 months after the cyclone hit Odisha coast. Some toxic heavy metals like Copper (Cu), Lead (Pb), Nickel (Ni), Cobalt (Co), Manganese (Mn), and Iron (Fe) exceeded the Environmental Protection Agency (EPA) standards at many locations in both the seasons. Non-conservative behavior of nutrients indicates well mixed nature of lagoon which is also indicative of good primary productivity. Northern sector (NS) of the lagoon is susceptible to eutrophication being riverine influenced region. Southern sector has more stable ion chemistry as a result of least freshwater discharge, constant supply of saline water, and lesser water renewal.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Combined with micro-seismic exploration results, an unsteady production model for multi-branched fractures in bounded tight fractured reservoirs has been established in this paper, and by means of Laplace transform, point source integration, Stehfest numerical inversion, and semi-analytical solutions to the production model have been obtained. The accuracy of model simulation has been verified through the fitting analysis of the theoretical model and field production data. The influences of fracture branch number, inter-porosity flow coefficient, storage coefficient, branched fracture density, and drainage area on production have been analyzed. According to the calculation results, the larger the fracture branch number, the higher the decline rate in the early stage; in addition, the dimensionless production curves in the late stage coincided with each other; basically, inter-porosity flow coefficient affects the productivity of only the inter-porosity flow interval; the greater the inter-porosity flow coefficient, the higher the production; storage coefficient mainly affects the early productivity of volume-fractured wells; the greater the storage coefficient, the higher the early production, but the productivity decline rate is similar at different storage coefficients; fracture density mainly affects the early productivity of volume-fractured wells; the larger the fracture density, the smaller the productivity, but with the reduction of fracture density, the influence of fracture density on productivity is less obvious; a larger reservoir drainage radius leads to later entering of energy depletion stage. Much attention shall be paid to the optimization of productivity influence factors, and they shall be taken into account as comprehensively as possible in the actual production process.〈span〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/12517_2019_4348_Figa_HTML.png"〉 〈/span〉 〈/span〉〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The processing and analysis of airborne geophysical data for polymetallic mineralization in Aghkand area at East Azerbaijan Province (NW Iran) were carried out with a view to establishing the prospective mineralized zones. This was done in two stages: (i) The magnetic and radiometric data were used to produce different maps including total magnetic intensity (TMI), reduction to the pole (RTP), magnetic lineation, intrusive, ternary, alteration, and other maps as well as the updated geological map of the area which when correlated with the geological map shows the concentration of potential areas at the western part; and (ii) the fractal model of concentration-area (C-A) was applied to find the main anomalous areas of RTP map, and the results were checked with geological units. The main anomalous areas in the RTP map were found from the western to the southwestern part of the area, consisting of andesite, tuffs, and dacite rocks. For validation purposes, the log-ratio matrix was used to correlate the main anomalous areas derived from the RTP map with mineral potential map. The prospective map of potential polymetallic mineralization was developed through integration of different exploration datasets using step-wise weight assessment ratio analysis (SWARA). The overall accuracy rate of RTP map when correlated with mineral potential map is 99%. Results are in good compliance with airborne geophysics data and indicate the presence of intrusive masses which is probably located in the western part of the study area.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Global geopotential models play a fundamental role in height transformation to convert the Global Navigation Satellite Systems (GNSS)-based ellipsoidal heights into orthometric heights in several geosciences applications. The U.S. National Geospatial-Intelligence Agency (NGA) is preparing to release the Earth Geopotential Model 2020 (EGM2020) in the near future. Prior to that official release, two primary geopotential models (PGM17 and PGM18) will be distributed to selective members for assessment in different regions worldwide. Within the activities of that working group, the new PGM17 geopotential model has been obtained and judged over a regional scale in northeast Africa, and over a national basis of Egypt. The assessment has been carried out using terrestrial gravity and GPS/leveling datasets within a GIS environment. The utilized dataset consists of 231 terrestrial gravity points in northeast Africa, 247 measured gravity points in Egypt, and 978 GNSS/leveling stations in Egypt. Three other GGMs have been included in the comparison stage, namely GECO, EIGEN-6C4, and EGM2008. For each model, grids of gravity anomalies and geoidal undulations have been computed and, then, compared against the corresponding values at known terrestrial data. Next, statistical measures of mean, range, and standard deviations of the discrepancies have been analyzed. For northeast Africa area, the accomplished results indicated that the PGM17 attains 100% improvements over the old EGM2008, while the GECO, and EIGEN-6C4 models resulted in improvements of 11%, and 1% respectively. Accordingly, it can be concluded that PGM17 represents the gravitational field over northeast Africa in a more enhanced manner. On a national scale, the GGMs assessment has been performed, over Egypt, in two steps: using gravity data, and using GNSS/leveling data. The findings emphasize that PGM17 noticeably enhance the performance of EGM2008, when compared against terrestrial gravity stations in Egypt, by almost 55%. Furthermore, the assessment over GPS/leveling stations concluded that the overall improvements of PGM17 are approximately 54%. Other GGMs did not produce a comparable improvement level in both case studies. Thus, it can be concluded that PGM17 is significantly precise than the other investigated GGMs in representing the gravitational field over Egypt in particular and northeast Africa in general.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The flaws that exist in rock masses may lead to crack propagation and instability of rock masses. Epoxy resin is often used to fill in flaws and to reinforce the fractured rock masses. Previous studies on the combined influence of grouting with epoxy resin and flaw geometry (flaw thickness and inclination angle) on the strength and failure pattern of rock masses are rare. In this research, rock-like specimens with an unfilled flaw having different geometries were fabricated and tested under uniaxial compressive load under both unfilled flaw and epoxy resin filled flaw conditions. The specimens had flaw thicknesses of 1 mm, 2 mm, and 3 mm and flaw inclination angles of 0°, 30°, 45°, 60°, and 90°. The experimental results reveal that for the specimens with an unfilled flaw the UCS drops in the range of 7–17% as the flaw thickness increases, but failure patterns do not change as the flaw thickness increases. UCS also dropped as the flaw inclination angle increased from 30° to 60° and then increased when the inclination angle increased from 60° to 90°. For the specimens with an unfilled flaw, the minimum UCS of about 62% of the intact UCS of the model material was obtained for 60° flaw inclination angle. For the specimens grouted with epoxy resin, as the flaw thickness increases, the UCS decreases in the range 16–21% when the flaw inclination angle is 30°, 45°, and 60°; but the UCS changes negligibly for the flaw inclination angles of 0° and 90°. For the specimens with a grouted flaw, the minimum UCS of about 74% of the intact UCS of the model material was obtained for flaw inclination angle of 60°. For grouted flaw, a maximum UCS almost equal to the intact UCS of the model material was obtained for 0° and 90°. The failure patterns of these grouted specimens are affected by both the flaw thickness and flaw inclination angle. The strengthening factor 〈em〉D〈/em〉〈sub〉s〈/sub〉 is used to indicate the grouting effect; a larger 〈em〉D〈/em〉〈sub〉s〈/sub〉 represents a stronger grouting effect. When 〈em〉α〈/em〉 = 0° and 90°, 〈em〉D〈/em〉〈sub〉s〈/sub〉 of a specimen with a larger flaw thickness is larger than that of a specimen with a smaller flaw thickness. When 〈em〉α〈/em〉 = 30°, 45°, and 60°, the thickness has little influence on the 〈em〉D〈/em〉〈sub〉s〈/sub〉 in this angle range. 〈em〉D〈/em〉〈sub〉s〈/sub〉 of the specimens with the flaw inclination angle of 0° is much higher (22% to 43%) than that of the specimens with the flaw inclination angles of 30°, 45°, 60° and 90° (14% to 24%). For the specimens with the flaw thickness of 1 mm, 2 mm, and 3 mm, 〈em〉D〈/em〉〈sub〉s〈/sub〉 increases slightly as 〈em〉α〈/em〉 increases from 30° to 60°. The effect of grouting on the failure patterns and strength of the specimens has a close relationship with the flaw thickness and flaw inclination angle. The above conclusions are new findings, which can provide useful information for estimating the failure mode and grouting effect of fractured rock masses grouted with epoxy resin.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In order to control the deformation of concrete face rockfill dams and improve the safety and stability of concrete face rockfill dams, this study uses the finite element analysis method, statistical analysis method, and numerical calculation to systematically study the stress and deformation characteristics of concrete face rockfill dam and its anti-seepage wall under complex geological conditions. The numerical simulation of the secondary development platform based on finite element software shows that the deformation caused by the foundation compression deformation, rheological deformation, and hydraulic coupling effect is the main cause of the large deformation of the overburden dam on the overburden layer. Among them, the foundation compression deformation is the main source of foundation deformation, and the deformation caused by rheological deformation and hydraulic coupling effect is the main source of secular deformation. Rockfill compression deformation is the main source of dam deformation, and the contribution of rheological deformation to dam deformation is greater than that caused by hydraulic coupling effect. In this study, the stress deformation and leakage characteristics of concrete face rockfill dam are analyzed, and the statistical laws of mechanical properties of concrete face rockfill dam are revealed. The sedimentation of the dam crest of most concrete rockfill dams is less than or equal to 0.40% H (H is the height of the face rockfill dam), and the sedimentation of most dams during the completion period is less than 1.0% H. After water storage, the panel deflection is close to the dam crest sedimentation value. Most of the dam’s panel deflection is less than 0.40% H, of which more than half is less than 0.2% H. Large rockfill deformation is the main cause of panel tensile stress, as well cracking and crushing damage.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Before uncovering an outburst coal seam in crosscut and shaft, it is necessary to detect the effect of outburst prevention measure applied to the seam, which is a key step and the last link for ensuring the safety of coal miners. However, in the working face where outburst prevention measures have been taken, the large number of densely arranged discharge boreholes, as well as the difficulty in sealing pressure-measuring boreholes, makes it extremely hard to accurately detect the effect of the measure. In order to solve this problem, this paper studied the relationship between the initial rate of gas emission from the borehole (IRGEB) and the outburst danger through carrying out experiments on a self-designed oblong simulation device of outburst coal seam and a detection device of IRGEB. In addition, it proposed a method of testing the prevention effect using the initial volume of gas emission from the borehole (IVGEB) per unit length which actually refers to the time integral of IRGEB per meter. The experimental results show that IVGEB grows with the increase of outburst danger, but its critical value varies with the types of coal seams and gasses. As a result, it may take over 20 days to get the critical value of outburst detection of a specific coal seam. For this reason, this paper presented a simplified method of determining the critical value of IVGEB per unit length. When this method is applied, the total time taken up can be enormously reduced to shorter than 4 h just by drilling another borehole for measuring the IVGEB. The field application results indicate that the method can quickly detect whether outburst danger has been locally eliminated. Hence, it can be regarded as a very applicable method for the rapid detection of outburst prevention effect before coal uncovering in crosscut and shaft.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Sustainability of plant production activities and improvement of irrigated lands in arid and semi-arid regions totally depend on efficient use of available water resources. Such an efficient use of water resources can be provided through assessment of water–yield relationships and identification of proper irrigation programs, schedules, and operational principles. There are no studies carried out to determine water–yield relations of oleic-type sunflower plants grown over large areas in Konya plain. In this study, different irrigation intervals (S) and crop-pan coefficients (〈em〉K〈/em〉cp) were used in drip irrigation of sunflower plants in Konya which is located at the Middle Anatolia in Turkey. The primary objective was to determine the effects of irrigation levels and intervals on yield and quality parameters of sunflower plants. Experiments were conducted in 2013–2014 growing seasons in 3 × 5 factorial design with 4 replications. Three different irrigation intervals (S〈sub〉5〈/sub〉:5, S〈sub〉10〈/sub〉:10, and S〈sub〉15〈/sub〉:15-day) and five different crop-pan coefficients (Kcp〈sub〉1.25〈/sub〉:125% of pan evaporation, Kcp〈sub〉1.00〈/sub〉:100% of pan evaporation, Kcp〈sub〉0.75〈/sub〉:75% of pan evaporation, Kcp〈sub〉0.50〈/sub〉:50% of pan evaporation, and Kcp〈sub〉0.00〈/sub〉:rain-fed without irrigation) were used in this study. In an average of 2 years, the greatest seed yield (5481 kg/ha) was obtained from S〈sub〉10〈/sub〉Kcp〈sub〉1.25〈/sub〉 with the greatest water consumption (748.7 mm). As compared with S〈sub〉10〈/sub〉Kcp〈sub〉1.25〈/sub〉 treatment, about 25% decrease was observed in yield of Kcp〈sub〉0.75〈/sub〉 treatments irrigated at 5- and 10-day intervals. Such a decrease was identified as 15% in Kcp〈sub〉1.00〈/sub〉 treatments irrigated at 15-day intervals. Therefore, for optimum seed yields from sunflower plants grown in Konya plain, irrigation intervals should not exceed 10 days. Also, crop-pan coefficient should be taken as 1.00 for high seed yields. Again, in an average of 2 years, irrigation water use efficiency (IWUE) of the treatments varied between 0.70 and 3.70 kg/m〈sup〉3〈/sup〉 and water use efficiency (WUE) values varied between 0.53 and 0.75 kg/m〈sup〉3〈/sup〉. The average yield response factor (〈em〉k〈/em〉〈sub〉y〈/sub〉) was identified as 1.14. Since the value is greater than 1, it was concluded that sunflower plants were sensitive to water deficits under Konya conditions.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Shallow rock and soil have a heat transfer temperature difference with the external environment, which can affect the external temperature through natural ventilation. In order to study and research the ventilation and energy saving of underground buildings based on this point, this study uses natural ventilation, field measurement, and DeST numerical simulation method to test the actual natural supply air rate of Zhengzhou metro station and the temperature, humidity, and CO〈sub〉2〈/sub〉 concentration in the station. After further simulation analysis, the energy-saving design method and operation mode that make full use of natural ventilation are proposed in the end, and the energy-saving advantages that natural ventilation can bring are further explored. The results show that during the ventilation season, increasing the natural ventilation in March, April, and November can improve the thermal environment in the station and reduce the opening time of draught fan, saving the energy consumption of the fan operation, while in the months when the outdoor temperature is lower, such as in January, February, and in December, maintaining the existing natural ventilation is able to meet the station temperature requirements. It can be seen that the design of this study is reasonable and has achieved the expected effect. It can use the effect of natural ventilation on the metro station to achieve energy saving.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The contamination of arsenic (As) in soil and groundwater has posed serious hazards to food chain and ecosystem. The aim of the present study was to assess the impacts of different biochar (rice husk biochar and plant biowaste biochar at 10 and 20 t ha〈sup〉−1〈/sup〉) on the retention and immobilization of As in wheat. For this purpose, soil and herbage samples were collected in the vicinity of Gujranwala, Pakistan, and characterized for different physicochemical parameters. Pot experiment was carried out on wheat plant to check the effect and uptake of As (at two concentrations, i.e., 10 and 15 mg L〈sup〉−1〈/sup〉) from irrigation water as affected by biochar. The results of the collected samples showed a minimum concentration of As and maximum concentration of lead (Pb) in Gujranwala City. Moreover, iron (Fe), chromium (Cr), and manganese (Mn) were the dominant elements in the sampling area. The application of biochar increased the plant biomass of wheat as compared to control. Among the studied biochars, the application of plant biowaste biochar significant increased the retention and immobilization of As at a higher level (15 mg L〈sup〉−1〈/sup〉). However, the rich husk performs better at lower As level (10 mg L〈sup〉−1〈/sup〉). Both the studied amendments increased the immobilization of As but plant biowaste biochar was more effective. The plant waste biochar could be used to improve agricultural production in polluted soil by minimizing the risk of food chain contamination.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Scale effect and acoustic emission characteristics of rock damage are two important topics in rock engineering research. In this paper, considering different rock scales and establishing the 3D numerical rock models by means of PFC software platform firstly, the mechanical properties and acoustic emission characteristics were studied. Finally, based on the acoustic emission, characteristic discussed the damage evolution law of the rock models. The research result shows that the multi-scale mainly affects the peak strength, peak strain, and elastic modulus of the mechanic properties, affects the maximum acoustic emission event number, strain range of serious acoustic emission events of the acoustic emission characteristics, affects the damage rapid increase and damage failure stages of the damage evolution process. The stress-strain curves, acoustic emission events curves, and damage variable curves can be divided into three stages and different scales have different effect on these stages.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Among different methods of underground mining technology adopted for coal extraction, bord and pillar mining is the most popular and predominant method of underground mining in India. This method is characterised with small capital investment and faster rate of return on capital. Varying geomining conditions demand scientific approach for design of supports in depillaring panels. In view, this there is a decisive lack of judgement on support design, given the geomining conditions. Support design methods in vogue for depillaring districts do not takes into account, among other parameters, the inclination of the coal seam and direction of in situ stress. Thus, there exists a need for research work aimed at investigating the effective role, inter-alia, of direction of in situ horizontal stress and inclination of coal seams to ensure a better condition of roof and efficient design of effective support system. The authors through this paper intend to address similar problems being faced by the industry. Detailed numerical models for one depillaring panel in Thesgora Mine and in two depillaring panels of Kakatiya Khani (KTK)-KTK-1 and KTK-5 Incline mines respectively of Bhupalpalli area under study have been developed. The models are then calibrated using the empirical relations of pillar strength. Stage-wise extraction in the models is carried out to simulate the change in stress and displacement as the mining activity progresses. Based on the geo-mining data and the numerical models, the rock load heights at four strategic locations namely split gallery, slice, junction and goaf edge have been evaluated in all the depillaring panels under study. Generalised equations for rock load height at different strategic locations in a depillaring panel have been developed. The said empirical relations for rock load height have been derived using parametric study of the numerical models developed for depillaring panels of the selected mines. The equations so developed have a correlation coefficient of maximum 87.8 % and a minimum of 80.5%.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Eastern syntaxial bend of the Himalayas has developed due to continued subduction of the Indian plate below the Tibetan plate to the north and the Burmese plate to the southeast. The Lohit River, which is one of the most important tributaries of the Brahmaputra, flows through the granodioritic terrain of the Mishmi Massif along deep gorges. Tectonic evolution of a terrain controls its drainage pattern and it is possible to trace back the tectonic forces involved through time and space in terrain evolution by morphometric study and the basin parameters. Integration of earthquake epicentral data further enhances understanding of the tectonic processes. It is distinct that the portion of the Lohit Basin bounded by the Parlung Fault to the east and the Po Chu Fault to the west, both trending northwest-southeast, is subsiding whereas the adjacent peripheral blocks on two the sides of this down moving block are relatively uplifted. The study shows two distinct uplifted tectonic zones with different tectonic behaviours. The zone located in the upper reach of the basin beyond the Po Chu Fault got tilted towards west while that of the lower reach tectonic zone, which is sandwiched between the Po Chu Fault and Lohit Thrust, got tilted towards southeast. These two tectonic zones are seismically active and got many major seismic events in the recent past including 1950’s Great Assam earthquake. The present study also indicates strong influence of tectonics in drainage basin development in the Mishmi Massif.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Qozlou Fe skarn deposit is located at the Abhar–Mahneshan belt of the Central Iranian Zone. It is associated with Upper Eocene porphyritic granite that intruded into the Upper Cretaceous impure carbonaceous rocks. The Qozlou granite has high-K calc-alkaline affinity and is classified as subduction-related metaluminous I-type granitoids. Skarn aureole in the Qozlou is composed of endoskarn and exoskarn zones, with the exoskarn zone being the main skarn and mineralized zone. It includes garnet skarn, garnet-pyroxene skarn, pyroxene skarn, epidote skarn, and pyroxene-bearing marble sub-zones. The Qozlou Fe deposit is 300 m long and 5–30 m wide. Magnetite is the main ore mineral associated to pyrite, chalcopyrite, and pyrrhotite. Garnet, clinopyroxene, actinolite, epidote, calcite, and quartz occur as gangue minerals. Covellite, hematite, and goethite were formed during the supergene processes. The ore and gangue minerals have massive, banded, disseminated, brecciated, vein–veinlets, replacement, and relict textures. EPMA data indicate that garnets have andradite–grossularite compositions (Ad〈sub〉39.97–100〈/sub〉–Gr〈sub〉0–49.62〈/sub〉) and clinopyroxenes have diopsidic composition (En〈sub〉29.43–42.5〈/sub〉–Fs〈sub〉14.31–20.99〈/sub〉–Wo〈sub〉43.08–50.17〈/sub〉). Based on mineralogical and textural criteria, skarnification processes in the Qozlou skarn can be categorized into three discrete stages: (1) isochemical (metamorphic–bimetasomatic), (2) metasomatic prograde, and (3) metasomatic retrograde. Anhydrous calc-silicate minerals (garnet and clinopyroxene) were formed during the prograde metasomatic stage, while ore minerals and hydrous calc-silicate minerals were formed during the retrograde ore-forming sub-stage. Temperature and ƒO〈sub〉2〈/sub〉 conditions range between 430 and 550 °C and 10〈sup〉−26〈/sup〉 and 10〈sup〉−23〈/sup〉, respectively, for the metasomatic prograde stage. The retrograde metasomatizing fluids had likely ƒS〈sub〉2〈/sub〉 = 10〈sup〉−6.5〈/sup〉 and temperatures 〈 430 °C at the beginning of the ore-forming sub-stage.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper presents the results of the geological and geotechnical studies of the rock masses along the Meram railway tunnel. The study area consists of limestone which is the base rock and covers a large area between the entrance and exit portals and sandstone which is only observed at the slope of the hill that overlies the tunnel. Results obtained from rock mechanics testing indicate that the limestone along the tunnel route is a moderately strong rock with an average uniaxial compressive strength of 61.88 MPa. Rock mass qualities of the rock units along the tunnel were determined by means of rock mass rating (RMR), Geomechanics Classification (Q) system and New Australian Tunneling Method (NATM). The study shows a very poor-to-fair rock mass conditions, with a rock mass rating (RMR) ranging from 40 to 49 and rock mass quality (Q-system) ranges between 0.69 and 2.52. The limestone was classified according to NATM into two ground categories, which are B2 (friable) and B3 (very friable). Correlations with the RMR, Q-systems and NATM suggested rock bolts and shotcrete as a suitable preliminary support system for the rock mass during excavation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Reshian area lies in the Lesser Himalayas (LH) in Jhelum valley, Azad Kashmir. The present study is carried out to investigate detailed petrological, geochemical, and geochronological characterization of granitic gneiss. Petrological investigation exhibits that the protoliths of Rashian granitic gneiss (RGG) are syenogranite to monzogranite. Geochronological study infers the protoliths formed in the Neoproterozoic (823 ± 14 Ma and 843 ± 12 Ma), representing the crystallization age of early granitic magma. Petrographical and geochemical study suggests the characteristics of the RGG are S-type, less Si, rich K, depletion in rare earth element (REE), the enrichment of light rare earth element (LREE), negative Eu anomaly, alkali to alkali-calcic, and peraluminous to slightly metaluminous granite. Meanwhile, the study implies the source of the RGG was derived mainly from partial melting of greywacke. Moreover, they have initial 〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr ratios ranging from 0.705823 to 0.714078, and initial εNd values varying from − 34.3079 to − 15.1398, revealing that the magma of the RGG was sourced from the fractional melting of the crustal material. Additionally, the RGG was emplaced in the post-collisional setting with the nature of syn-collisional granites and volcanic arc granites, implied probably due to the thermal perturbation associated with the breakup of the Rodinian supercontinent.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Formation of meander cut-off focuses some distinct migratory nature of the main channel over time and through the application of quantitative indices as cut-off ratio and diversion angle, the process of formation has been explained through its evolutionary stages. Comparative study of hydrological and morphological characteristics between the cut-off lakes and the main Jalangi depict that the main channel was active than the present and it is going to decay with time. These cut-off lakes are evident as the past hydrological characteristics of the channel. There are three meander bends have been identified among the selected 61 curves which have high tendency of cut-off formation near future. The main controlling components are shear stress, radius of curvature, and tortuosity which have been considered to quantify the mechanism in positive and negative perspective. It will help to identify more possible cut-off lakes near future. This morphological dynamism is distinctly interlinked with the remarkable land transformation in the last 25 years. The changing behavior of land utilization are characterized by huge increase of cultivated lands and settlement which have mostly converted from uncultivated waste lands, agricultural wet lands (seasonaly used), and water bodies respectively.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Pore size distribution and associated heterogeneities of thinly bedded beach-bar sandstone reservoir from upper fourth member of Eocene Shahejie Formation (Es4s) are characterized with the help of mercury injection capillary pressure (MICP) and nuclear magnetic resonance (NMR) transversal relaxation time (T〈sub〉2〈/sub〉) data. Permeability and porosity are two represented important characteristics of rocks that control the movement and storage of fluids. The aim of this paper is to establish relationships between pore throat sizes and reservoir quality. The results derived from thin-section petrography, scanning electron microscopy (SEM), MICP, NMR T〈sub〉2〈/sub〉 relaxation time, and 3D micro-CT (μ-CT) are compared to characterize pore space dimensions and types comprehensively. Average pore throat size from MICP ranges between 0.47 μm and 2.83 μm while maximum pore throat size ranges between 2.48 μm and 7.36 μm. The combination of pore size distribution obtained from MICP and NMR seems appropriate to cover the range of pore size from beach-bar sand and overcome the individual method limits. Afterwards, digital 3D μ-CT tomographic images are used to characterize and visualize pore space and pore network model to compare with the experimental data. MICP and NMR experiment showed generally bimodal (meso and micro) pore size distribution. Usually mesopore corresponding to intergranular pores is dominant, while heavily cemented sandstones show large amounts of intercrystalline micropores. Complex and heterogeneous beach-bar sandstone reservoir requires comprehensive study program to evaluate the reservoir.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉We investigated effect of biochars (BCs) and nitrogen (N) fertilizers on soil selected characteristics, growth of maize, and soil N transformations in a pot experiment. Maize was grown in soil amended with control (no BC), and three BCs different in feedstock (rice-straw biochar (RSBCC), vegetable-waste biochar (VMBC), poultry-manure biochar (PMBCC), and N application (control, 0.25 g N kg〈sup〉−1〈/sup〉 soil using urea and NH〈sub〉4〈/sub〉NO〈sub〉3〈/sub〉). At harvest, agronomic parameter, soil (pH, EC, SOM, total N, and NO〈sub〉3〈/sub〉-N), and plant analyses were done. The results showed the improvement in soil nutrient contents and yield with application of BC and N. The soil pH diminished in BC treatments where N was used. The soil EC was increased in RSBC treatment than the control but decreased in NH〈sub〉4〈/sub〉NO〈sub〉3〈/sub〉 application irrespective of all BC treatments. The SOM was improved in all BC treatments under N. The NH〈sub〉4〈/sub〉 concentration in plants and total soil N were significantly enhanced in BC treatments even without N. The plant growth and nutrient uptake were more influenced in NH〈sub〉4〈/sub〉NO〈sub〉3〈/sub〉 than urea. Comparing BCs showed overall better performance of PMBC than RSBCC and VWBC. Overall, the combined supply of PMBCC and NH〈sub〉4〈/sub〉NO〈sub〉3〈/sub〉 has advantages of improving plant growth, and soil fertility by changing N dynamics.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Tuz Golu (Salt Lake) Underground Gas Storage (UGS) Project in Turkey is being implemented. In some of salt caverns, natural gas is currently stored. While analyzing the data of Tuz Golu UGS project, it was observed that this location is appropriate for safe underground natural gas storage due to its rock salt with high purity and very low permeability. In this study, many numerical simulations for a salt cavern in Tuz Golu UGS project at different gas withdrawal and injection rates were conducted by using TOUGH + RealGasBrine simulator. According to the results of these numerical simulations, the temperature inside salt cavern reduced below 0 °C from 53 °C within 20 days at a rate of gas withdrawal of 3.33 million standard m〈sup〉3〈/sup〉/day due to Joule-Thomson effect. The temperature inside salt cavern reduced below 0 °C within 25 days, 40 days, and 60 days at a rate of gas withdrawal of 2.5, 1.67, and 0.833 million standard m〈sup〉3〈/sup〉, respectively. In order to avoid fracture around the walls of salt cavern, the temperature change inside salt cavern should not be higher than 30 °C. In the numerical simulations, there is no gas seepages from the salt cavern to other neighbor salt caverns, which are 600 m away owing to very low permeability of salt rock in the study area. The implication of this study is that gas withdrawal and gas injection profiles are quite important to keep the temperature inside salt caverns at an optimum range for safe natural gas storage.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The focus of this study is to delineate groundwater-bearing zones for the drilling of boreholes to ensure sustainable water supply in the Cape Coast municipality using the vertical electrical sounding (VES) technique. A total of 25 VES points were conducted of which thirteen (13) were test drilled. The VES survey was conducted using the ABEM SAS 1000 Terrameter with the Schlumberger configuration and a maximum half current electrode spacing (AB/2) of 100 m. The VES data were processed and interpreted using the ZONDIP resistivity inversion software. Both qualitative and quantitative interpretations were used to ascertain the best points for drilling a successful borehole (yield 〉 13 l per minute). The criteria used in selecting a promising site for test drilling are as follows: the nature of the curve (observing the nature of the VES curves), the overburden thickness and the bedrock resistivity. The study revealed a drilling success rate of 90% with an average borehole yield of 118 l/m. A careful review of the resistivity variation with depth revealed that areas with the increasing trend of resistivity from the overburden to the bedrock are most likely to produce unproductive wells whilst areas with decreasing resistivity trend from the overburden to the bedrock are more likely to produce productive wells. The reflection coefficient (Rc) values generally range between − 0.8274 and 0.1210 and suggest a highly fractured formation with respect to the Sekondian rocks. Within the granite, the Rc showed more competent formation with values ranging from 0.4040 to 0.6136. A comparison between the depth to bedrock as predicted by VES and the borehole logs was in strong agreement with the correlation coefficient value (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.9089). On the other hand, the study revealed a relatively week correlation (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.4325) between the final drilled depth and the borehole yield. The study also finds four major groundwater-bearing zones in the terrain which range between 12 and 28 m, 31 and 40 m, 43 and 59 m, and 80 and 104 m. The bedrock resistivity values most likely to yield productive boreholes with yields greater than 13 l/m range from 54 to 845 ohm-m with a decreasing resistivity between the overburden and the bedrock. Bedrock resistivities more than 900 Ωm with an increasing resistivity between the overburden and the bedrock are most likely to be unsuccessful. Within the terrain, the average depth for drilling productive wells in the Sekodian rocks is 68 m with the final borehole depth ranging from 35 to 120 m. The study therefore has demonstrated the efficacy of the VES technique as a tool in delineating groundwater potential zones for the drilling of boreholes.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The objective of this paper is to develop a forecasting model for the annual rainfall depth in Saudi Arabia (SA). The annual rainfall data of four stations are used as a pilot study. The coefficient of variation (CV) of the rainfall is relatively moderate (CV 〈 0.8). The annual rainfall records have been modeled by applying the first-order autoregressive AR(1) model with and without skewness. Normality has been tested (skewness coefficient, 〈em〉γ〈/em〉 〈 0.7 and kurtosis coefficient with respect to normal 〈 0.64 except one station). Most of the data has proven to normality. Autocorrelation analysis has shown that the lag one autocorrelation is relatively low (〈em〉ϕ〈/em〉〈sub〉1〈/sub〉 〈 0.3). This reflects poor autocorrelation which is typical in arid and semi-arid regions due to scarcity and intermittency of the rainfall. Monte Carlo approach has been applied to estimate the confidence interval of the forecasted series. Although the first lag autocorrelation was weak (the correlation time scale is in order of 1 year), the modeled annual rainfall by AR(1) is fairly good. The results also showed that there is no significant skewness in the data, and therefore, the use of AR(1) without including skewness is best to represent the data. The developed procedure can be further applied to other stations in SA.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉2D seismic cross-sections calibrated to exploration wells allow highlighting the structural styles along a structural transect from the N–S axis, west of the Bouthadi–Chorbane anticline to the foreland, with a major regional tectonic anomaly striking roughly E–W along the subsurface Atlas front of the foreland basin.〈/p〉 〈p〉The interpretation of structural data and seismic profiles allow deciphering clearly the occurrence of Late Cretaceous–Paleogene inversion structures, accounting for folds detached along the basal intra-Triassic salt decollement level. These contractional structures in part result from the Middle–Late Eocene compressional events, which induced the first strong positive inversion in both the Atlas domain and adjacent foreland. The growth of these positive structures is outlined by angular unconformities, sedimentary gaps, and differential subsidence within the Paleogene deposits.〈/p〉 〈p〉The foreland area is characterized by a thick-skinned tectonic inversion style, where the Pre-Triassic basement is decoupled from its Jurassic–Quaternary sedimentary cover by a general decollement level located at the Upper Triassic/Lower Jurassic interface. The deformation features imaged by seismic sections are in agreement with such thick-skinned style controlled by deep-seated faults presumably inherited from the Pan-African basement.〈/p〉 〈p〉A regional structural cross-section is presented and discussed, crossing the N–S axis and outcrops of the South Atlas Front in the west and, then, running through the major structural anomaly of Chorbane and the foreland basin to the east. This regional cross-section has been also balanced and restored to its initial and intermediate geometries, i.e., after the Tethyan and Cretaceous extensional events and Paleogene compressional events, thus documenting the major tectonic anomaly of Bouthadi–Chorbane in the foreland as well as the overall structural evolution of the Atlas fold and thrust belt.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉There is a need for a unified strength criterion, which is a variable suitable for describing the different strength properties of different types of geomaterials. In this study, a unified nonlinear strength (UNS) criterion is proposed based on the Lade-Duncan criterion for the sake of versatility to capture the complex strength behaviors of geomaterials under three-dimensional (3D) stress paths. The strength curves in this theory are a series of continuous and smooth conical loci that covers wide ranges of the meridian and octahedral planes to describe the nonlinear strength behaviors of soils. The strength curves are located between von Mises and Lade-Duncan strength curves in the deviatoric plane in the principal stress space. Verifications between the proposed criterion and experimental data from triaxial tests found in the literature show that this new criterion is able to reasonably reflect the three-dimensional (3D) strength properties and strength nonlinearity of a variety of geomaterials.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In addition to aggregates, cement, and water, reinforcing steel is one of the key building components of precast products. Steel price fluctuations observed on global markets have a large impact on the cost of production of precast products made of reinforced and prestressed concrete. An important issue is, therefore, the proper planning of steel orders and deliveries to the precast concrete plants. A significant number of competing warehouses and construction warehouses offer diversified steel prices, which are subject to frequent changes in relatively short periods. This results in a problem in the selection of an appropriate procurement strategy by precast concrete plants. An additional unfavorable factor is the ordering of reinforcing steel that is too large in relation to the demands of the precast concrete plants, resulting in high costs of its storage in the warehouses or storage yards. In this paper, the issues of optimal planning and delivery of plain, ribbed, and prestressing steel were discussed. For the research and calculation purposes, supplies of steel from four wholesalers to four different precast concrete plants were assumed. In addition, the types of steel and the class of bars used to reinforce the elements were discussed. A different level of unit prices for the purchase and delivery of steel in each warehouse and a different demand for each of the four concrete plants were also assumed. As a result of the analyses carried out, a model was developed, including the strategy of purchasing and supplying plain, ribbed, and prestressing steel with the assumption of minimum costs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Seasonal freezing and thawing of permafrost can cause great damage to the environment and the geological structure, resulting in instability of engineering structures. Therefore, it is very necessary to continuously monitor the deformation of Qinghai–Tibet Railway (QTR) in the seasonal permafrost region. In this study, 38 Sentinel-1A SAR images, spanning from October 20, 2014 to March 26, 2017, were explored for displacement monitoring of QTR in permafrost area. Displacement time series (about 2.5 years) of QTR from Dangxiong to Yangbajin (QTR_DY) section were achieved. Seasonal characteristic of the displacement, negatively correlated to temperature (〈em〉R〈/em〉 = − 0.833) and precipitation (〈em〉R〈/em〉 = − 0.727), is shown. Possible uneven settlement in two sections along QTR_DY is detected. A multivariate displacement model, considering both temperature and precipitation, which is proposed, can be used for railway displacement prediction.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this study, we introduce a new complex conformable derivative and integral with noninteger order 〈em〉α〈/em〉 which coincides the classical complex derivative and integral for 〈em〉α〈/em〉 = 1. We examine basic properties of these newly defined derivative and integral such as Cauchy-Riemann equations, conformability and fundamental theorem of complex conformable integral. As an application of the new operators, we solve some types of complex conformable differential equations.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The effectiveness of natural fractures restricts petroleum exploration and development of tight gas sandstone reservoirs. Taking Xujiahe Formation in Yuanba area of Sichuan basin as an example, the effectiveness of natural fractures is studied by using outcrop, core, thin slice, imaging logging, and production data. Natural fractures of Xujiahe Formation are relatively well developed and structural shear fractures are the most developed ones, which mainly composed of high angle fractures and almost perpendicular to rock stratum. Statistics of fracture basic parameters (outcrop, core, and thin slice) are done and the fracture density is calculated. The main strike of the fractures is NW-SE, nearly E-W, nearly S-N, and NE-SW, formation period can be divided into four stages. The controlling factors of the fracture effectiveness are fracture filling and opening degree, fracture formation period, and the maximum horizontal principal stress. There are obvious differences in the effectiveness of different fracture types and occurrences, the effectiveness of high angle fractures, vertical fractures, and the fracture strike of NW-SE, nearly E-W is the best, which is of great significance for the development of tight gas sandstone reservoirs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Uniaxial compressive strength (UCS) value of a rock material is one of the most important design parameters in engineering practice and related fields of geosciences. Through this importance, prediction of UCS values of rock materials from nondestructive quicker and simpler tests are widely preferred. The aim of this study is to predict the UCS values of five carbonate rock groups including marble, dolomite, two limestones, and travertine from longitudinal ultrasonic wave velocity (Vp), Schmidt hardness rebound number (SHR), and cubic sample sizes (〈em〉L〈/em〉). For this aim, a total of 90 cubic samples with 7, 9, and 11 cm edge sizes were prepared. Chemical, petrographical, and basic physical properties of the sample groups were investigated. After Vp and SHR values, UCS values of all samples were determined. By using multivariate regression analyses (MR), different UCS prediction equations from 〈em〉dry unit weight (γ〈/em〉〈sub〉〈em〉d〈/em〉〈/sub〉〈em〉)〈/em〉, Vp, SHR, and also 〈em〉L〈/em〉 values were proposed. Prediction performances of proposed model in which Vp, SHR, and 〈em〉L〈/em〉 are input parameters was also analyzed by least square support vector machines (LS-SVM) method. Prediction performances of the MR and LS-SVM models were analyzed by coefficient of determination (〈em〉R〈/em〉〈sup〉2〈/sup〉), efficiency (〈em〉E〈/em〉), and root mean square error (RMSE) performance measures. These values were calculated as 0.867, 0.799, and 16.616 respectively for the LS-SVM model and 0.781, 0.749, and 18.561 respectively for the MR model. The LS-SVM method was found to be successful in the prediction of the UCS values from nondestructive test data of carbonate rocks.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Realizing both of the effective weak edge detection and fake edge suppression is an extremely challenging problem facing high-resolution remote sensing (HRRS) image segmentation. To address the problem, an HRRS image segmentation method combining phase congruency with local homogeneity is proposed by advantageous complementarities. Firstly, the Log Gabor Filter is used to extract phase congruency information. Then, the local homogeneity index 〈em〉J〈/em〉 value is adopted to optimize the edge detection results. On this basis, an objective function optimization strategy based on minimizing inter-scale mutual information is proposed, and a parameter-adaptive model of edge response is established. In the end, the segmentation results are obtained by multi-scale region segmentation and merging based on this model. Two sets of HRRS images are used in experiments, and the results are compared with the 〈em〉J〈/em〉 value-/phase congruency-based models, the well-known commercial software e-Cognition, and a traditional gradient-based segmentation method, respectively. Both visual and quantitative evaluations have demonstrated the effectiveness of the proposed method.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Extensive use of groundwater and abandoned agriculture practices causing desertification and environmental degradation of ecosystem is of major concern to planners. Ecologically sensitive areas like Western Ghats in India which is identified as World Heritage Site by UNESCO is facing similar threat. Construction of suitable artificial recharge structures at appropriate location is essential to improve the groundwater resource for environment protection. Study of watershed morphology has indicated the elongated shape, low runoff, and highly permeable subsoil conditions. The study proposes integration of multi-criteria-based land suitability analysis with runoff modeling in HEC-HMS to identify suitable structures and their location for artificial recharge of ground water. Remote sensing and GIS tools were used for mapping, integration, and modeling of artificial recharge process. Results demonstrate the suitability of farm ponds along first-order streams, percolation ponds, and subsurface dykes in middle of watershed and check dams in higher-order stream network. It is concluded that improved groundwater resources facilitate better environment protection and ecological balance.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The need to use locations which are hitherto swamps or recreation centers to construct more building facilities that range from medium to huge structures within the University main campus informed the decision to embark on this study. Structures within the subsurface layers were investigated by analyzing the distribution pattern of some geophysical properties such as compressional wave (P-wave) velocity, shear wave (S-wave) velocity, and Poisson ratio. The near-surface layers were identified from the first break picks of P-waves velocities. Moreover, the dispersive capability of the surface wave produced S-wave velocity information that identified different geological structures based on the orientations of the lithological layer’s rigidity. The P-wave velocities reveal three-layer structures of thicknesses between 3.0 m to 6.0 m and 2.0 m to 5.0 m for Layer 1 and Layer 2 respectively. These layers are in three categories of “Complex”, “Mild,” and “Simple” based on the distribution pattern of shear velocities. Poisson ratio analysis shows two categories of Topsoil/Lateritic layer of less than 2.0 m (thin) and between 2.0 m and 4.5 m (thick). Areas identified as “Complex” structure with thick Topsoil will require comprehensive foundation design than other areas especially when erecting huge building. Whereas, locations around the New Halls (NHs) may require simple foundation plan for building development compared to other areas since it is characterized by thin Topsoil and simple layer structure. The study will assist construction engineers with prior information of the structures of subsurface layers which thereby reduce time and cost of building development within the University campus.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The present work considers a management model for the sustainable development of an exploited coastal aquifer of the Gaza Strip, which includes different demands depending on water quality types into a regional hydrologic-economic-agronomic model. The uniqueness of this study is its consideration of two-separated demand functions one for fresh water and the other one for saline water, as well as effect of saline-water quality relationship on agriculture. This study identifies the optimum infrastructure of desalinated seawater and treated wastewater to fresh and saline levels. It also allocates water of different qualities (fresh and saline) among water sectors and between districts. Results show several important management outcomes: (i) the shadow value of saline water for all districts is larger than the cost of treating brackish water to fresh level is $0.30/m〈sup〉3〈/sup〉. Therefore, the desalination of saline groundwater water to saline water level may be beneficial in Gaza districts. (ii) The shadow value of fresh water for all districts is larger than the cost of desalination ($0.6/m〈sup〉3〈/sup〉). Accordingly, the desalination of brackish water to fresh water level is also beneficial. (iii) The areas of potential crops that use treated wastewater to saline level are proportionally increased to reduced abstraction from groundwater. Moreover, the sensitivity analysis indicated that, reduced abstraction from the groundwater would better allocate scarce water among competing users and better predict infrastructure sizing to fresh and saline treatment levels.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Biochar (BC) is a carbon-rich pyrolyzed material widely used in agriculture for soil amendment in order to enhance crop production and improve soil quality, carbon sequestration (C-sequestration), and mitigation of atmospheric C. Various functions of BC make it valuable; however, the heterogenic properties of BC raise questions regarding its suitability in a particular environment. The present study explored the heterogenic properties of BC with the aim of aligning its uses for soil and the environment. Different types of BC were prepared from feedstocks (FS) of sludge (S), animal waste (AW), and plants originating in the Mediterranean region. Physical and chemical characterization of BC was performed to evaluate its suitability for use in the Mediterranean region with regard to plant nutrient availability. To achieve this, pH, electrical conductivity (EC), and proximate, ultimate, and nutrient analyses were performed. Moreover, scanning electron microscopy (SEM) was also undertaken, and the C-stability of BC was observed using thermogravimetric analysis. Plant FS–derived BC exhibits a high moisture content, volatile matrix, and fixed and total carbon (TC) compared with sludge biochar (SBC) and AW-derived BC. A high calcium carbonate (CaCO〈sub〉3〈/sub〉) content was observed in AW-derived BC. Furthermore, the porosity of BC revealed that soil microbes may be sustained inside the porous structure if used for soil amendment. The different FS-oriented BC studied here could potentially be used to amend soil. The AW-derived BC and plant FS–derived BC could be a good source of immediate nutrient release for plant growth in agriculture and C-sequestration, respectively.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Systematic microscopic observation and analysis reveal multi-stage mineral fillings and fluid charging in the Sinian (Ediacaran) Dengying and the Cambrian Longwangmiao Formation in the Gaoshiti-Moxi structure, Central Sichuan Basin. Reservoir pore space is filled with five different stages of minerals from the edge to the center: fine crystalline dolomite, rimmed bitumen, coarse crystalline dolomite, stripped or oil droplet-like bitumen, and calcite or quartz, respectively. Sr, C, and O isotopic analysis for fine crystalline dolomite and the late stage calcite and quartz filled in reservoir pore space indicate that, prior to oil-generating window of the Cambrian Qiongzhusi Formation, the Sinian Dengying and the Cambrian Longwangmiao Formation were within the same connected and open fluid system. But after the gas-generating window, the Cambrian Longwangmiao Formation evolves gradually into a relatively independent and closed fluid system. By restoring the paleo fluid pressure, it is found that the paleo fluid pressure coefficient of the Sinian Dengying Formation has gone from 1.0, 1.1 to 1.2, 1.2, 1.2 to 1.3, and 1.0 to 1.1 at different evolution stages of source rock (at corresponding Ro value of 0.5, 1.3, 1.7, 2.0, and over 2.8, respectively), and the paleo fluid pressure coefficient of the Cambrian Longwangmiao Formation has varied from 1.0, 2.1 to 2.2, 1.8 to 1.9, 1.6 to 1.8, and 1.55 to 1.75. The pressure restoration result reveals that overpressure has never occurred in the Sinian Dengying Formation during the geological history, but overpressure commonly occurred in the Cambrian Longwangmiao Formation, and the values varied at different evolution stages of source rock. This pressure evolution process also demonstrates that the Sinian Dengying and the Cambrian Longwangmiao Formation, prior to the oil-generating window, were within an identical normal pressure fluid system. Meanwhile, it also matches well with the present exploration discoveries: the overpressured gas pools of the Cambrian Longwangmiao Formation are preserved up to now and hold hundreds of billions cubic meters of gas reserves, while the Sinian Dengying Formation contains residual normal pressure gas pools that formed after the adjustment of natural gas over a large area.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The use of crop models in sloping areas is questionable when relief is not taken into account, as relief affects infiltration, radiation, and aerodynamic processes. The objective of this work is to evaluate the performance of FAO-AquaCrop model in simulating crop evapotranspiration, water balance, and biomass production in hilly areas using in situ measurements. The experiment was conducted in the Cap-Bon region, north-eastern Tunisia, on two wheat fields located on opposite sloping rims (A and B) and one control field (C) on a flat terrain: field A is SE-oriented with 5% slope and B is NW-oriented with 6% slope. Three flux stations were used to monitor automatically actual evapotranspiration (ET) and climatic factors whereas soil moisture and biomass production were measured manually. Model’s outputs were compared to actual measurements using statistical indicators: slope of the regression line, root mean squared error (RMSE), and the coefficient of determination (〈em〉R〈/em〉〈sup〉2〈/sup〉). Actual ET varied between 1 and 2 mm during crop initial stage and 3–4 mm during mid-season stage. The ET/ETo ratio during mid-season was 0.81, 0.74, and 1.03, respectively for fields A, B, and C, well below the commonly used value of 1.15. Comparison between measured and simulated ET shows a substantial overestimation of the model in sloping fields with 6–20% higher averages and a RMSE of 0.47–0.77 mm/day. AquaCrop seems to simulate reasonably well water balance, particularly in flat conditions. RMSE of water content in the top 100 cm soil-layer was in the range 41–67 mm/m, representing a relative error of 11–21%. Simulated and measured biomass values presented similar trends (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.86–0.94) with a systematic difference, indicating that AquaCrop outputs could be improved by a correction factor.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper investigates the structural properties of compacted loess by focusing on the influence of structural changes incurred by varying sample moisture content on matric suction and stress-strain characteristics of unsaturated compacted loess. Two tests are conducted on unsaturated compacted loess with different structural properties: soil-water characteristic curve test and triaxial shear test. Samples are maintained and tested at the same moisture content and dry density through humidification or dehumidification. Test results show that structural changes incurred by sample moisture content markedly influence the soil-water characteristic curve of unsaturated compacted loess. Below the plastic limit, matric suction increases with increasing sample moisture content. At the optimal sample moisture content, unsaturated compacted loess exhibits a homogeneous micro-pore aggregation structure and thus a relatively high suction. In the optimal structural state, the stress-strain curve was located at the top of the stress-strain graph. For moisture contents below the optimal sample moisture content, the degree of structural weakening is relatively low, and the stress-strain curve gradually moves down the stress-strain graph. For moisture content above the optimal sample moisture content, the degree of structural weakening of the soil sample is relatively high, and the stress-strain curve moves to the bottom of the stress-strain graph. A structural parameter 〈em〉m〈/em〉〈sub〉〈em〉ɛr〈/em〉〈/sub〉 is defined that could reasonably reflect the structural properties of compacted loess and is of great significance for evaluating the engineering quality of compacted loess.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Egyptian calc-alkaline younger granitoids represent part of broadly distributed late collisional high-K calc-alkaline granitoids in the northern Arabian-Nubian Shield. In the Eastern Desert of Egypt, these granitoids have a significant economic value that they are commonly associated with rare metal-bearing granites. Maktali granitoids are located in Central Eastern Desert and they constitute a two-phase pluton, which consists of leucogranites and monzogranites. They intrude the country metavolcanics with sharp contacts. These granitoids are slightly peraluminous and moderately to highly fractionated high-K calc-alkaline granitoids. Leucogranites and monzogranites were emplaced at temperatures 699.8-8.28.8°C and 757.2–909.6°C and under pressure 1.22–4.8 and 2.36–2.98 kbars respectively. Leucogranites and monzogranites were emplaced at depths 3.28–22.96 km and 6.36–8.5 km and they were crystallized under log Oxygen fugacity between − 13.2 to − 16.1 and − 11.6 to − 14.7 respectively. They are magnetite-series granitoids and their crystallization was controlled by NNO fugacity buffer. Leucogranites and monzogranites share the same magmatic source and they were emplaced during late-collisional stage by melting of crustal source rocks may occur as a consequence of decompression following delamination of the lithospheric root and slab breakoff. Maktali leucogranites could be generated by partial melting and subsequent fractional crystallization of mafic lower crust with addition of melts from the mantle. Maktali monzogranites show distinctive characteristics of rare metal-bearing granites that they contain Fe-columbite and transitional micas. Field and textural evidences together with chemistry of columbite, micas, and trace element behavior suggest the magmatic origin of monzogranites. Moreover, REEs in monzogranites show a pronounced Eu anomaly and a well-visible tetrad effect, supporting their generation by fractional crystallization and fluid-rock interaction during the late stage of granite crystallization.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Biochar has a propitious role in the agricultural lands as a sustainable soil management and drought mitigation approach. The present research work aims at evaluating the structural characteristics of wheat straw, rice straw, sugarcane bagasse, and wood shaving biochar in clay loam and sandy loam soil at a rate of 0, 10, and 20 tons ha〈sup〉−1〈/sup〉 and their comparative role for improving soybean growth, biomass water content, apparent water productivity, Zn, Mn, and Fe status under three moisture conditions (75%, 50%, and 40% of field capacity). Wood shaving and sugarcane bagasse biochar amendments in sandy loam soils caused favorable adjustments in the BET surface area, pore surface area, pore volume, pore radius, water-holding capacity, EC, and pH. However, in clay loam soil, there was traced a decline in BET (N〈sub〉2〈/sub〉) surface area and other pore properties, while the highest soybean shoot and leaf fresh and dry biomass were recorded with 10 tons ha〈sup〉−1〈/sup〉 wood biochar in both types of soils under optimum and moisture-deficit conditions. Apparent water productivity with 10 tons ha〈sup〉−1〈/sup〉 wood biochar in soybean plants under 75%, 50%, and 40% moisture was 77%, 137%, and 157% higher, respectively, than that in control in the clay loam soil, while 153%, 149% and 135% higher, respectively, than that in control in the sandy loam soil. In both types of soils, soybean leaves with 10 tons ha〈sup〉−1〈/sup〉 sugarcane bagasse biochar under all three moisture regimes had the highest Zn concentration. Under deficit moisture leaf, Mn concentration was found to be increased in wood biochar amendments and the highest Fe concentration was found with 20 tons ha〈sup〉−1〈/sup〉 rice straw biochar amendments in both types of soils, while under 40% moisture with most biochar treatments, leaves had high Fe concentration.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The quantification and assessment of groundwater are of great significance for the urbanization and town planning in an area. The current study has been carried out for quantification and assessment of groundwater quality zones by using geo-electrical technique in Faisalabad area (73° 06′ 08″–73° 11′ 59″ E; 31° 35′ 00″–31° 40′ 39″ N) of Pakistan. Vertical electrical soundings (VES) at six locations were conducted by Schlumberger configuration up to 300-m depth of investigation. Modeling technique is used for the interpretation of apparent resistivity, and the true resistivities of various subsurface lithologies were recorded from 2.10 to 55 Ω m for the depth of investigation. Three sand-dominant aquifers were identified at depth intervals of 0–50 m, 50–100 m, and 100–300 m. The VES results are compared and calibrated with the available borehole data taken from the tube wells drilled in the vicinity of the study area. The GIS technique is applied for the preparation of water quality zonation maps. Some of the groundwater quantification parameters such as total volume of the alluvium, total volumes of the water content, and active storage are estimated through GIS applications. Top geo-electrical layer (0–50 m) is dominated by low resistivity zone (10–25 Ω m), having an active storage of 0.71 km〈sup〉3〈/sup〉. Intermediate geo-electrical layer (50–100 m) comprised coarse sand with low-to-medium resistivity zone of 10–35 Ω m, showing a low active storage (1.01 km〈sup〉3〈/sup〉). Deep geo-electrical layer (100–300 m) is dominant by very low resistivity zone (〈 10 Ω m) in the whole area. This 200-m-thick zone is possibly an admixture of fine sand, clay, and silt, having a high active storage (4.06 km〈sup〉3〈/sup〉). The quality of water deteriorates with depth, and aquifer zones saturated with marginal-to-saline groundwater are interpreted below the fresh water zone at all the probe sites. The active storage of the lower geo-electrical layer (100–300 m) indicates a huge water potential but it is trapped in medium sand and alternative layers of clay. The intermediate geo-electrical layer (50–100 m) is comparatively better in quality but has low ground water potential.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The formations containing soluble salt structures are located on the upper sections of underground coal beds in Central Anatolia Region, where ground waters infiltrate into coal seams through faults and with other environmental factors that result in corrosion danger upon machinery/equipment employed within mining operations. In order to define the corrosion rates of steel component samples, tests performed with bore water representing regional underground hydrosphere, mine water for mining conditions, and pure water for control purposes. The corrosion mechanisms were implemented according to “Standard Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens-ASTM G1-03 (2011),” and the microscopic images of steel surfaces have been examined ASTM G1-03, (〈span〉2011〈/span〉). At the end of experiments, support steel sample mass loss is defined as lowest for bore water and highest for mine water and pure water. The rates of corrosion for bore water is 0.010, mine water 0.182, and pure water 0.180 (mm/year). Evidently, actual underground water corrosiveness is assessed as high; therefore, suggestions are developed for the mining enterprises to take into consideration for safe and secure operation in such environment.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The aims of this study are to evaluate the physico-chemical properties of groundwater in the Engiz Aquifer System, determine the sea water intrusion, and investigate suitability of groundwater for both agricultural and drinking purposes of Samsun City in Turkey. It was interpreted whether groundwater was suitable for drinking and the parameters analyzed were checked according to the standards determined by the Turkish drinking water standard (TSE 266 〈span〉2005〈/span〉). The use of groundwater for irrigation purposes was classified based on the Water Pollution Control Regulation of the Turkish Republic, Criteria for Inland Surface Water Classification (WPCR 〈span〉2004〈/span〉). The groundwater samples of the Engiz Aquifer System were analyzed for major anion and cations, trace elements, pH, EC, and TDS. The groundwater samples are Ca-Mg-Na-SO〈sub〉4〈/sub〉 and Ca-Mg-Na-Cl water types. The groundwater samples are not suitable for drinking because of the high levels of Na, Al, As, Fe, and Ni. Besides, %Na and SAR values indicate that the water is suitable for only salt-tolerant and semi-tolerant crops under suitable irrigation circumstances. According to the Mg Hazard and PI values, 30 and 70%, respectively, of the groundwater samples are not suitable for irrigation in the basin. It is thought that the groundwater salinity is increasing in the future because the groundwater wells are close to the Black Sea coast and there is some intrusion of saline marine waters.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study aims to determine the activity concentrations of natural radionuclides (〈sup〉226〈/sup〉Ra, 〈sup〉232〈/sup〉Th, and 〈sup〉40〈/sup〉K) in the agricultural soil of southeastern Nile Delta, Egypt, in order to assess their influence on the occupational radiation health hazard indices. It was found that the mean activity concentrations of 〈sup〉226〈/sup〉Ra, 〈sup〉232〈/sup〉Th, and 〈sup〉40〈/sup〉K were 35.53, 23.59, and 266.41 Bq kg〈sup〉−1〈/sup〉, respectively. The effect of the industrial activities in the study area on the activity concentrations of radionuclides is slight for 〈sup〉226〈/sup〉Ra while negligible for 〈sup〉232〈/sup〉Th and 〈sup〉40〈/sup〉K. Soil characteristics especially the fine particles play the major role in the distribution of 〈sup〉40〈/sup〉K, while the distribution of 〈sup〉232〈/sup〉Th is less influenced by the soil characteristics. On the other hand, the distribution of 〈sup〉226〈/sup〉Ra shows no obvious association with these characteristics. The calculated radium equivalent activity index (Ra〈sub〉eq〈/sub〉) and external hazard index (H〈sub〉ex〈/sub〉) fall within the save rang. However, those of absorbed dose rate (D〈sub〉ex〈/sub〉) and annual effective dose (AED〈sub〉ex〈/sub〉) exceed the world average values in about 16.7% and 61.1%, respectively. The calculated values of the excess lifetime cancer risk (ELCR) are higher than those of the world average. This implies the high probability of developing cancer over the lifetime of the farm workers. In this study, we recommend performing periodical inspection for the industrial activities and their wastes in the study area and monitoring the level of activity concentrations of different radionuclides in the studied soil as well as the cultivated crops.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper proposes a new approach to solving the scalability problem in stitching and registration of satellite images. The image stitching process is mostly utilized to capture an image of an entire object, whose parts fall in separate but overlapping mosaics. Due to their high resolutions and huge sizes, the stitching of satellite mosaic images is time- and resource-consuming process. The work presented in this paper proposes a resource- and content-aware, scalable stitching technique. The main idea is based on measuring and assessing the available hardware resources of the machine, on which stitching process runs, and scaling the resolution of the images accordingly. Moreover, preprocessing is not needed, and the adjustment is performed dynamically at run time. The effectiveness of the proposed technique was assessed by partially registering overlapping satellite mosaic images of the island of Cyprus and Lake Van. The scalability tests are performed on varying numbers and sizes of the overlapping LandSat-8 satellite images.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Morphometric analysis of a river basin is essential to identify and assess seasonal changes in drainage basin characteristics, understand the groundwater potential, and address issues related to management of soil erosion due to flash floods during the high flows. Nanganji River Basin is one of the least studied seasonal river basins in India which carry substantial flows during the monsoon period. In this study, morphometry of Nanganji River Basin, located in the central Tamil Nadu prairies, has been studied using remote sensing and GIS. The interrelationship between the various morphometric factors of the basin has been studied using a correlation matrix. Factor analysis has been applied to group the individual morphometric parameters into a smaller number of factors. Further, these factors have been studied in relation to the sub-basins to understand the existing relation between the factors and the sub-basins. Finally, the study identifies environmental issues of the Nanganji River Basin mostly related to the river flow regime which widens significantly during the monsoon months.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Floods are considered to be one of the natural disasters that seriously affect people’s lives and property every year. Although, delineation and determination of hydrologic basins and their morphometric parameters are difficult morphological tasks, GIS-based approach simplifies the investigation of various morphometric factors and helps to explore the correlation between the drainage morphometry and landform properties. The present study is aimed to investigate the spatial distribution of drainage basins around Jeddah–Makkah region and its surrounding areas (nearly 40,247 km〈sup〉2〈/sup〉) using GIS spatial analysis. The morphometric parameters of these drainage basins and their channel systems were estimated and calculated. The computed morphometric parameters are categorized into the following three main groups: linear, aerial, and relief features. The documentation of these parameters was, then, used to evaluate and construct flood hazard map of the region. Flood hazard map assesses five classes with varying degrees (very low, low, moderate, high, and very high) of flood hazard zones. Such hydrological hazard is mostly due to the basin’s area and its highest relief ratio, relative relief, and ruggedness factor. The flood hazard map shows that the city of Jeddah is in a moderate to high flood hazard zone, but most of the areas surrounding it are in moderate flood hazard zone. This indicates that during heavy rainfalls, flash flood could be generated in these areas which can be severely affecting the city. In addition, this study shows a remarkable correlation between theoretical concepts, data sets, and field observations, predominantly highlighting the role of geology and geomorphology in influencing the basin morphometry and identity.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The micropore throat of the Gao 3 section tight sandstone reservoir was studied using sampling and experimental (high-pressure mercury injection and scanning electron microscopy) methods. Based on the relative permeability, the reservoir can be divided into three categories: conventional, unconventional and low permeability. To determine the displacement pressure, porosity and other relevant parameters of various reservoirs, the mercury injection curve of all samples was projected to the same coordinate system. According to the position of the inflection point on the mercury injection curve of all levels of reservoirs, the pore throat was divided into three types: micropores, transition pores and macropores. Based on the theory that the throat is characterised by the mercury withdrawal curve, the throat in the present study is divided into three categories: the large throat, the medium throat and the small throat. Combined with the ordinate position at the inflection point, the critical point of micropore-throat classification of all kinds of reservoirs was determined. By analysing the histogram of pore-throat distribution of all kinds of reservoirs, the peak value of reservoir pore-throat distribution was determined. From the definition of expectation and variance in mathematics, the concept of grading parameters was introduced to determine the size and concentration degree of micropore-throat distribution at all levels of reservoirs, and a correlation analysis with permeability was performed to determine the control law of permeability.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Confined concrete (CC) is a new form of high-strength support. To verify it, the authors have developed a large-scale mechanical test system. With the test system, a full-scale laboratory experiment is conducted in this paper to compare the mechanical properties of CC and traditional U-shaped steel arches in a straight-wall semicircle. Both of the CC and the U-shaped steel contain the same amount of steel. The experiment is also developed to study the deformation characteristics and the bearing mechanism of various arch types. Based on the numerical calculation, the variation law of bearing capacity of the CC arch is studied under different influencing factors. The factors include wall thickness of steel tube, concrete strength, lateral pressure coefficient, and others. The results show that (1) The U-shaped steel arch is prone to local buckling instability, resulting in failure of the entire arch. In contrast, the CC arch has an ultimate bearing capacity of 1072.4 kN, which is more than 2 times that of the U-shaped steel arch; and it also has high later bearing capacity. (2) Under the action of compression and bending, the arch is damaged with the key failure position on its legs. The bending moment is the main factor for the arch failure, and its action effect is enhanced with the increase in the lateral pressure coefficient. In field application, arch legs should be reinforced to reduce the peak of the bending moment and increase the overall strength of the arch. (3) Compared with the strength of core concrete, the wall thickness of the steel tube has a more significant effect on the mechanical properties and economy of CC arches. In the arch design, the field geological conditions and construction convenience should be considered. So, the steel tube should be used with the minimum wall thickness which meets the requirements of the bearing capacity of arches; and the common brand concrete should be used. Based on the above research, CC arches are designed for support in underground engineering with complex geological conditions. The control effect is remarkable with an average deformation of the surrounding rock controlled within only 72.2 mm.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Coal and gas outbursts are related to the pore structure of coal, in order to study the pore characteristics of high-temperature coal mine and the impact of invasive water on its development, the invasive water treatment and water bath process at the high temperature of coal samples taken from Yangliu Mine, Guqiao Mine, and Dingji Mine were carried out. The pore characteristics of the raw coal (R-coal) samples and invasive water coal (IW-coal) samples were analyzed through the mercury intrusion porosimetry (MIP) and CO〈sub〉2〈/sub〉 gas adsorption testing. The results show that the pore connectivity in macropore phase is significantly better than that in mesopore stage. And the porosity, total pore volume, total surface area, and micropore ratio increase with the increase of R-coal rank. The mesopore ratio decreases as the R-coal rank increases, and macropore ratio has the trend of “decrease-increase” with the increasing R-coal rank. After the water intrusion into R-coal samples at high temperature, the porosity increases significantly, however, there is no effect on the pore connectivity. The total surface area, micropore ratio, and micropore volume of the coal samples decrease because of the invasive water, leading the adsorbed gas to convert into free gas. The total pore volume, mesopore ratio, and macropore ratio increase, increasing the channel of gas diffusion and permeability. The results provide a theoretical basis for exploring the effect of the invasive water on gas migration in the high-temperature coal mine.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The young granites of El Maghrabiya area located at the Central Eastern Desert, the southwestern part, are intensively altered along faults, fractures, and shear zones. Microscopically, the studied granites are classified as syenogranite and the altered portion exhibits features of ferrugination and episyenitization. This granite belongs to the high silica and low calcium, iron, and magnesium granites reflecting their origin from highly fractionated potassium-rich crustal material. El Maghrabiya syenogranites are generally uraniferous especially the altered portion that is characterized by high radioactivity. The hydrothermal activity is responsible for the formation of the anomalous zone characterized by extensive episyenitization and ferrugination processes. The ferruginated syenogranite has higher concentrations of uranium and thorium than the other altered granites (episyenitized). The present study revealed that zircon, fluorite, fluorapatite, and iron oxides are the most predominant U-bearing minerals in addition to uranophane that recorded in the ferruginated variety. The studied syenogranites characterized by two thorium ranges where the fresh granite exhibits the low range (22–45 ppm) and the altered granite characterized by the higher range (68–185 ppm) indicating that there are two pulses of the magma generating El Maghrabiya young granites. Uranium and thorium of the first generation are mostly attributed to the accessory minerals and related to the magmatic processes while the second generation is characterized by low Th/U ratio and high uranium content that is enriched by the hydrothermal solutions.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The mechanical properties of rock materials are remarkably affected by water content. To reveal the effect of water content on the strength and deformation properties of siltstone, which was collected from the quarry of Zhundong Coalmine, the scanning electron microscope and uniaxial compression tests of siltstone specimens were carried out with a water content of 0%, 0.5%, 1.5%, and 2.8%. Conventional triaxial compression test was conducted in dry and saturated conditions. The test results showed that the strength and deformation parameters of siltstone are weakened with different degrees after water absorption. The deformation of the plastic yield stage in the stress-strain curve decreases with rising of water content, while the loss rate of uniaxial compression strength continues to increase until reached saturated state. The strength of dry and saturated specimens varies regularly with confining pressure, and their relationship can be described with the exponential criterion. In addition, it is observed that microscopic damage of siltstone specimens accumulates as water content increases. The hydration of clay minerals reduces the local cohesion of specimens, and the hydrolysis of quartz minerals in crack tip region promotes subcritical crack growth during the loading process, which collaboratively results in the bearing capacity of saturated specimen decrease. The results can provide a reference for the analysis of rock strength and damage mechanism under the action of water erosion.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A mega-scale fold is exposed near Jeddah city in the western-central part of the Arabian Shield. This fold extends NE for about 35-km long and 12-km width and occupies the northwestern block of a distinct linear feature known as Ad-Damm Shear Zone. It is composed essentially of foliated, sheared, and mylonitized metamorphic and plutonic rocks. Para and ortho-gneisses were an amphibolite facies condition whereas greenschist facies units were represented by metasedimentary and metavolcanics. Image processing and field-based structural analysis, in addition to micro structural investigations of the mega-scale fold, indicating that the ductile dextral-sense of shear was overprinted by a brittle regime associated with the evolution of Ad-Damm shear zone. The Ad Dam mega-scale fold is a shear-related structure, north plunging overturned anticline. Mylonitization and dextral shear-related structures were developed during a transpressional regime. The Ad-Damm fold is a structural system that illustrates the evolution history of the Arabian Shield associated with the development of the NE-wrench fault. This fault started as an early plastic followed later by a brittle tectonic regime. The present study indicates that Ad-Damm shear zone and several sub-parallel dextral shears of NE-trends which located in the western side of the Arabian Shield represent a conjugate antithetic shear to the NW- trending sinistral shear of the Najd fault system.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Aiming at deep profile control in water flooding reservoirs, a heterogeneous combination flooding system, composed of dispersed particle gel (DPG) and a zwitterionic surfactant (THSB), was developed. The mean particle diameter was adjusted and then the DPG morphology and diameter were characterized using a laser scanning, confocal microscope, and dynamic light scattering. The effects of DPG concentration, temperature, pH, and salinity on THSB interfacial tension (IFT) were investigated. A method for determining DPG concentration was proposed, and the dynamic retention and migration mechanisms of the particles were evaluated, using cores with different permeabilities. Finally, the oil displacement mechanism of the combination flooding system was explored through visual simulation experiments and scanning electron microscopy. The results showed that the particle diameter was 2.5 μm, that compared with a surfactant system, the IFT of the combination flooding system was relatively low, and that the temperature, pH, and NaCl content of solutions had little effect on THSB IFT. Since specific matching relationships between DPG particles and reservoir pore throats existed, the retention amount and injection pressure were improved with the increased core permeability. Visual simulation experiments revealed the oil recovery mechanism of the combination flooding system. This combination flooding system can be used in reservoirs under varied conditions, as the particle diameter can be adjusted on a case-by-case basis, and the THSB surfactant proved to be high-temperature resistant and high-salinity tolerant. The combination flooding system can be applied to deep profile control and oil displacement, in oil fields.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Rainfall is an imperative producer of readily available water and is of great importance to most economies of the world. Similarly, for the Indian economy, especially for agribusiness, Indian rainfall is a serious entity. Indian rainfall in the months from June to September constitutes approximately 80% of the annual rainfall. This rainfall is highly variable over space and time, which causes floods or droughts in various parts of the country. Thus, a thorough study of rainfall variations and the factors that affect rainfall is required. Therefore, the objectives of the present study are (a) to analyze all-India rainfall along with its subdivisions (northwest, west-central, northeast, central northeast, and peninsular India) and (b) to determine correlations between rainfall and the Southern Oscillation Index (SOI) for three different subperiods: 1949–1965, 1966–1990, and 1991–2016. The statistical analysis of rainfall data and the regime shift analysis method form the basis of this analytical study. Our results showed a significant downward trend in rainfall from July to October for 1949–2016. The monsoon season (June to September) showed a strong positive correlation with SOI for the subperiods 1949–1965 and 1966–1990, which weakened in the period 1991–2016. The rainfall from October to December showed a strong positive correlation with the SOI during 1949–1965 that weakened in the later periods. This study’s results are helpful for decision makers, planners, agriculturists, hydrologists, and other experts for the proper management of water resources.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Building façade segmentation is essential for smart city-related applications such as energy consumption simulation or urban planning. In this paper, we take advantage of the horizontal self-similarity feature of building texture and propose a building façade segmentation algorithm based on K-means classification. First, the building texture images are rectified to orthogonal projection. Then, texture pixels in each horizontal line are classified into line segments using the K-means method based on CIE color distance. Next, a graph is generated where the nodes represent line segments, and the edges are relatedly connected with color distance attribute of its two nodes. The connected nodes (neighbor line segments) with similar color are aggregated based on which the building main structures such as floors and tiles are detected. The novelty of the proposed method is that the K-means classification is applied to the building texture pixels in a horizontal line that can improve the classification accuracy and increase speed. According to the experimental results, the proposed algorithm can achieve over 90% accuracy on the test dataset compared with traditional methods.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This research displays the influence of geogrid inclusions on the bearing capacity of rigid strip shallow foundations overlying sand dunes. An extensive chain of settings—containing plain fill case—is verified by valuing some factors as first geogrid reinforcement depth, vertical spacing between geogrid inclusions, and geogrid extension relative to the footing width on the mobilized bearing capacity. To achieve the research aims, a group of finite element analysis is carried out to assess the studied parameters. For the purpose of validation; two-dimensional plane strain finite element model is implemented completely similar to the previously built experimental model tests using Plaxis code version 8.2. The soil is represented by Mohr-Coulomb soil constitutive model, and the geogrid reinforcement is characterized by tension elastic elements which have only a normal stiffness. Well matching is detected between the physical and numerical model test results. The results designate that geogrid insertion can severely enhance the bearing capacity of rigid strip footing overlaying sand dunes. Additionally, it is revealed that the load-settlement performance can be considerably improved. The effectiveness of the geosynthetics loose fine sand composite increases to the maximum as the optimum values of the assessed parameters are reached.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Lower Silurian Longmaxi Formation black shale unit at the southwestern margin of the Yangtze Platform has a great potential to contain shale gas. Based on the geochemical and microscopic characteristics of the Longmaxi Formation black shale unit, the depositional environment and the characteristics of the silica in the black shale were analyzed. The mechanism whereby the Longmaxi Formation black shale unit in the study area was enriched in organic matter is discussed from the perspective of upwelling and sea-level change. The conclusions of the research are as follows: (1) The shale in the Gesala section with a total organic carbon (TOC) content greater than 2% is approximately 55 m thick, which is favorable for shale gas accumulation in the study area. (2) The Longmaxi Formation black shale unit was deposited in an anoxic marine environment. Marine primary productivity was high during the deposition of the Longmaxi Formation black shale unit. (3) The Longmaxi Formation black shale unit is rich in biogenic silica due to the development of ocean upwelling. (4) Upwelling and sea-level rise jointly controlled the enrichment of organic matter in the Longmaxi Formation black shale unit. The upwelling supplied nutrients and promoted biological reproduction, which promoted marine primary productivity. The higher productivity also contributed to the formation of an anoxic environment in the bottom seawater. The sea-level rise was favorable for the formation of a reducing deep-water environment and deposition of fine-grained sediments, which was beneficial to the preservation of organic matter.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Urbanization is one of the most important dimensions of contemporary global change. Urban growth affects life-supporting environment of human beings, as well as natural ecological system and biological composition. Thus, long time series urban land cover datasets with high spatial and temporal resolution are useful for understanding the dynamics of urban growth processes, providing great insights into urban planning and sustainable development in the future. For the first time, this study analyzes 55-year spatiotemporal patterns of urban changes in Shanghai, China, by integrating the historical Declassified Intelligence Satellite Photography (DISP) and Landsat time series data at 5-year intervals from 1960 to 2015. Here we applied different methods to detect urban land from DISP and Landsat images, respectively, and their accuracies were quantitatively analyzed and evaluated. The spatiotemporal patterns of urban growth were explored. The derived products showed that urban land cover increased at a rapid and accelerating pace with growth concentrated at the expanding fringes of existing urban clusters. Across the study region, the total urban area increased from 205.10 to 2259.97 km〈sup〉2〈/sup〉, at an average annual rate of 37.4 km〈sup〉2〈/sup〉/year, and the percentage of urban area increased from 3.33 to 31.96%, expanded by more than 10 times between 1960 and 2015. In addition, urban area increased over time in all directions; the relative proportions of the urban area in downtown and non-downtown changed dramatically over the study period, indicating that urban sprawl of the metropolis experienced major transitions under the effect of population increase, economic development, and policies.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Lower Cambrian marine shale has become a new target of shale gas resource evaluations in the complex geological region of southern China, where the Niutitang Formation is among the most important shale gas reservoirs. Recently, the micropore structural characterization and main controlling factors of the ancient shale have become popular research topics. The micropore structures of certain shale samples from the Niutitang Formation in the Micangshan tectonic zone were investigated at the microscale and nanoscale using low-temperature nitrogen gas adsorption (GA) and a combination of broad ion beam (BIB) milling and field-emission scanning electron microscopy (FE-SEM). Then, we analyzed how the mineral composition and thermal evolution affect the pore development in the Niutitang shale through the results of X-ray diffraction (XRD) and vitrinite equivalent reflectance (VR〈sub〉oequiv〈/sub〉) calculated by bitumen reflectance (R〈sub〉b〈/sub〉). The BSE images by the BIB/FE-SEM system show that multiple pore types are present in the ancient Niutitang shale and form a complex pore network under the influences of mineral contents and thermal maturation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The use of satellite images for mapping and analyzing linear structures and fracture systems in subsoil regions is essential to understand the subsurface groundwater path ways and traps. In this study, we apply Optimal Index Factor (OIF), principal component analysis (PCA), and directional filtering (Sobel) of several Landsat 8 bands for the wooded Waddai area in NE Chad. The application of the Sobel directional filter to these bands showed a robust performance for enhancing the discontinuity features and allowed better identification of the fault/fracture systems by the automated lineament extraction techniques. The results indicate that the ENE and WSW structural trends control the distribution and migration of groundwater, in good agreement with previous hydrological studies and published hydrogeological maps. New highly potential areas for groundwater exploration are identified on a lineament density map and verified by ground truth urban distribution.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A 150-m-long mineralized lamprophyre dyke intrudes mylonite-mélange at the eastern side of Wadi Sikait and granite at its western side. Its petrographic, mineral, and geochemical characteristics were investigated in order to determine its genetic history as well as the petrogensis of the hosted mineralizations. Rocks of the Sikait lamprophyre dyke have a porphyritic and, less commonly, aphanitic texture. They consist of REEs-U-Th- and Nb, Ta-bearing minerals in addition to Au and native nickel, zircon, and fluorite. The ratios of LREEs to each of the HREEs, MREEs, and HFSE are relatively high. The U and Th contents in the part of the dyke existing in granite are slightly high than those in that hosted by the mylonite-mélange. The Sikait lamprophyre dyke has a calc-alkaline affinity and metaluminous to peraluminous. Its parent melts were derived from a mantle metasomatised by carbonatitic fluids. The protolith was subjected to slight to moderate partial melting in shallow to intermediate depths. During the emplacement of the dyke, U was released from its mineral precursors, transported, and redeposited under favorable condition. Its concentration in the part of the dyke hosted by granite was increased by the action of young surficial processes. On the other hand, Au was derived from the ophiolitic metagabbros and serpentinites that over thursted on the mylonites. It was precipitated from mesothermal and epithermal solutions. The Sikait dyke was affected by several alteration processes; the most common of which is hematitization and metasomatic carbonatization.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In the present investigation, natural radioactivity in soil samples from the bauxite ore deposit in FONGO TONGO municipality of Menoua Division, Western Cameroon was assessed using gamma spectrometry. Priory analysis, the detector was calibrated for both energy and efficiency using standard sources. The investigated soil samples of NDIFONDA and APOUH were randomly collected. The observed specific activities of primordial radionuclides in soil from both study areas were comparably higher than the reference values of UNSCEAR, however varied within the exemption levels recommended in the IAEA basics safety standards. The observed average values of radium equivalent activity were 299.58 Bq/kg in NDIFONDA and 425.86 Bq/kg in APOUH. The observe value in APOUH were relatively higher than the recommended save value by ICRP while that of NDIFONDA were lower. Because majority of the houses in the study site are made of brick concrete, radiological health hazard parameters (air-absorbed dose rate (D) and total annual effective dose (ET)) were estimated to evaluate public exposure to natural radiation from soil. The observed values for D and ET were relatively higher than the recommended value of UNSCEAR (143 and 0.48 mSv/year, respectively) in both sites. In addition, the calculated values of excess lifetime cancer risk were slightly higher than the worldwide averages. Finding of this study revealed that long-term exposure to natural radiation in the study area might contribute to some health disease. Therefore, further studies need to be carried out to assess long-term exposure risk to radiation priory exploration of the mine.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper aims at investigating the meso-scale mechanisms that result in damage evolution in soil and rock mixtures (SRM). Although the macroscopic cyclic stress–strain response of SRM has been well investigated, the mesoscopic damage cracking mechanisms are still not well understood. In this work, artificial SRM sample with a rock block percentage (RBP) of 30% (mass ratio) was investigated by carrying out cyclic triaxial compression tests with a constant stress amplitude and low strain level, under tomographic monitoring using a 450 kV industrial X-ray computed tomography (CT). A series of 2D CT images were obtained at different loading stages throughout the test and from different positions in the sample using CT scanning. The results show that the hysteresis loop presents a sparse–dense–sparse pattern caused by the accumulation of plastic strain during the test. Besides, parameters of damping ratio and resilient modulus vary as increasing cycles, much energy loss, and decreasing resilient ability occur with large plastic strain. The study also finds that a linear relationship exists between the hysteresis loop area and total crack area extracted from the CT images. Volumetric dilatancy caused by the damage cracking behavior has closed link with the evolution of hysteresis loop, which are controlled by the meso-structural changes during sample deformation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Sistan in east Iran is vast, low slope tectonic lowland of which a great portion is consisted of alluvial-saline lands of dried out Hamoon lakes. Sistan district with a population density of 43 people per square kilometer is the most densely populated human ecosystem in east Iran. This population is distributed in more than 1000 cities, villages, and nomadic settlements. Sistan plain is extensively exposed to vigorous winds. In the last 5 years, with the spread of drought and drastic reduction of Hirmand River’s water flow, dust storms have become more severe and long lasting. Winds of 120 days are the most significant wind in the region which starts every year at the end of the spring and lasts all through the beginning of autumn, with a mean velocity of 100 km/h. This research utilizes a survey/descriptive method coupled with medical documents to rank the risk of destructive eolian sediment dispersion in different regions of Sistan alongside the frequency of citizen’s reference to medical centers due to respiratory problems or eye damages caused by these sediments during the summer of 2017. The research findings show more risk of dispersion of eolian sediments in human environment in near the Iranian-Afghan border. The Level of the risk of respiratory and eye damages for citizens exposed to dust distribution with the rate of distribution of eolian sediments in the environment is statistically significant. Human ecosystems (1) Dehno-Piran, (2) Bazzi-Allari, (3) Muhammad-Shah-Karam, and (4) Abbas-Rostam regions in Sistan area have the highest risk for citizens due to respiratory problems and eye damages caused by eolian sediment dispersion.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The quantitative model of the Earth is provided by optical and radar space-borne remote sensing global digital elevation models (GDEMs). GDEMs are fundamental for many geo-spatial analysis and demanded by several applications that need topographical data. Recently released ALOS World 3D 30 m (AW3D30) and 1 arc-second (~ 30 m) Shuttle Radar Topography Mission (SRTM) C-band GDEMs have the advantages of high quality and free availability from JAXA and NASA and much in demand in scientific community. In this paper, we comprehensively analyzed the discontinuities between AW3D30 and SRTM C-band GDEMs in country-scale calculating and interpreting the influence of terrain inclination and land cover classes. The coherence between two GDEMs was estimated by absolute horizontal and vertical accuracy analysis in the basis of model-to-model validation approaches. During the analysis, standard deviation and normalized median absolute deviation of height differences between GDEMs were utilized as the main coherence indicators. The frequency distribution of height differences and the incoherent outliers were presented by error distribution graphics and height error maps, respectively. The results clearly demonstrated the significance of ascending and descending orbits, terrain inclination, and land cover on the discontinuities.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Formation depiction is the progression that describes both physical and chemical properties of rocks and fluids through the exploitation of available log or core data. Geologic formations are generally heterogeneous in nature. Different types of well logs like caliper, SP, resistivity, gamma, sonic, neutron, and density logs are used to characterize formations. Formation temperature (T〈sub〉f〈/sub〉), porosity (Φ), permeability (k), formation water resistivity (R〈sub〉wf〈/sub〉), formation water saturation (S〈sub〉w〈/sub〉), etc. are the main characteristics of a reservoir. In this study, a gas field located in Brahmanbaria district, Bangladesh, with latitude 24° 00′ 58.6″ N and longitude 91° 07′ 14.4″ E is examined. The geothermal temperature gradient was 0.00735 °C/m with a temperature of 43.33 °C at depth of 3535 m. Four sand zones (identified as B, D, F, and H), four shale zones (identified as A, C, E, and G), and four sand mixed with shale zones (specified as I, J, K, and L) were mapped between depth 2800 and 3557 m. The average porosities (combining sonic, neutron, and density porosities) of zones B, D, F, and H were 25.5%, 26.2%, 23.95%, and 20.65%, respectively, with permeabilities of 84.26 mD, 49.64 mD, 35.01 mD, and 296.38 mD. Considering all the parameters (porosity, permeability, resistivity, and formation water saturation), it is shown that zone H (3036–3186 m) is a more effective gas production zone.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Late Oligocene pre-Eonile paleoriver flows northwesterly over the Eocene Limestone Plateau in the east central Western Desert, west of the Nile Valley (Sohag), building an alluvial plain and leading to the karstification of the limestone bedrock, as paleoerosional surfaces and paleodolines. Knowledge of this alluvial karstification is completed with the detailed studies of the sedimentary evolution of the fluvial system and its contemporary deposition. Analysis of the sedimentological and geomorphological features allows discussing the natural environmental conditions that favored karst in the past and its main genetic mechanisms. The architectural elements of the fluvial deposits indicate that they were deposited in a gravel-dominated braided fluvial system, characterized by high availability of water and sediment supplies. The current study proves that genesis of paleodolines was mainly related to this high water supply. Some of them were progressively filled by syn-sedimentary deformed unconsolidated deposits. Such deformation is due to dissolution of the underlying sagging synclinal limestone, conditioning the location of sinking waters where preferential dissolution and later suffosion took place. A model for the evolution of the paleodoline fills is proposed and interpreted in three different stages: (1) gravitational processes developed and disorganized gravels were remobilized and dragged toward the created paleodolines; (2) flooding of the paleodolines acted as lakes where Gilbert-type deltas and gravel slope deposits accumulated, exhibiting several unconformities interpreted as a result of continued subsidence of the paleodoline related to dissolution; and (3) nondeformed fluvial facies sealed the whole deposits, marking the end of the karstification process. Combinations of different types of factors that could cause karstic subsidence and associated hazards include soluble rock lithology, paleoclimate, and deformational structure.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Low-permeability clays are characterized by a large amount of clay minerals and a special distribution of pore sizes, so their seepage behavior shows an obvious pore size effect. Therefore, conventional seepage theories show deviations in describing the seepage behavior of low-permeability clays. This paper analyzes two reasons for the pore size effect in low-permeability clay seepage: the pore distribution property and the electric double layer effect of the clay surface. Considering these two factors, the seepage theory of the pore size effect based on the microscale seepage of the circular tube model is proposed. The rationality of this theory is tested by the seepage experiments of natural undisturbed clay and artificial clay, and from these experiments, three beneficial conclusions are drawn: (1) The results of the pore size effect seepage theory are in good agreement with the experimental results and are better than the modified Kozeny-Carman equation; (2) The properties of the electric double layer have a certain regular influence on the seepage behavior of the clay; (3) Considering the properties of the soil pore size distribution, the results obtained by using the pore size effect theory are much closer to the experimental results than the results calculated using the average pore diameter of the clay.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Amu Darya Basin in Turkmenistan is a large petroliferous sedimentary basin. We analyzed the Callovian-Oxfordian succession of the Amu Darya right bank area based on Vail’s classic sequence stratigraphy and drill core, logging, seismic, thin-section petrographic, and geochemical data. We found that the Callovian-Oxfordian sequence can be divided into five third-order sequences (SQ1–SQ5) and 15 fourth-order sequences (sq1–sq15). A stratigraphic framework for the study area was newly established, based on these high-resolution sequence divisions. Two types of carbonate platform models were developed: (i) Callovian, in which the region was likely a ramp platform with a gradual slope to the east. It is mainly developedouter ramp and mid-ramp facies deposition which consists of micritic limestones, shoal grainstones, and reef limestones; (ii) Oxfordian, during which the region likely evolved into a rimmed platform with highly disparate sedimentation rates (low in the east) that were sensitive to sea level change, and a starkly different sedimentary landform that was high in the west and low in the east.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The 〈em〉Isparta Angle〈/em〉 (IA) is formed as a morphotectonic pattern and located in the north of the Antalya Gulf. It is a seismotectonically very active zone as in the Eastern Mediterranean Region. The shape of Isparta Angle is a wedge-like with flanks oriented NE–SW in the west and NW–SE in the east rather than compressional E–W-oriented structures preceding its present shape. It results from the clockwise and anti-clockwise rotation of the Anatolian Plate from the Early Paleocene to the Early Pliocene. In this study, we determined the neotectonic pattern of the IA by using arrival time data of P and S waves. We assessed the 3-D tomographic images from the data of local earthquakes. The tomographic results verified the major tectonic structures and discontinuities in the studied area. The results have revealed the young structural heterogeneities related to the seismotectonic zones. While the higher Vp and Vs distributions are determined in the shallow levels of the earth, low-velocity perturbations are extensively distributed at deeper levels of the crust. The seismotectonic activity, seen along heterogeneous zones, denotes the high-velocity perturbation and is related to the pre-existing faults. The results of checkerboard tests showed that the anomalies are reliable down to approximately 40 km depth. From the middle to the lower crust, the low-velocity zones are related to the geophysical and geological evidence in the Fethiye–Burdur Fault Zone (FBFZ) and the existence of mantle material is consistent with the partial melt in the upper mantle. Furthermore, the present study revealed the new active zones from 3-D tomographic results: the NW-trending Yalvaç, NE-trending Gelendost, and approximately N–S-trending Eğirdir–Kovada grabens existing in the northern core of IA.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The spatial distributions of naturally occurring radionuclides (〈sup〉226〈/sup〉Ra, 〈sup〉232〈/sup〉Th, and 〈sup〉40〈/sup〉K) in agricultural soils collected in the proximity of a coal-fired brick kiln located at Chittagong district were studied using HPGe γ-ray spectrometry. The obtained mean activity concentrations for 〈sup〉226〈/sup〉Ra, 〈sup〉232〈/sup〉Th, and 〈sup〉40〈/sup〉K were slightly higher than the world average values, which indicate the contribution of radionuclides via the fly ash deposition from the kiln. The maximum activity concentrations of 〈sup〉226〈/sup〉Ra, 〈sup〉232〈/sup〉Th, and 〈sup〉40〈/sup〉K in soil samples collected at a distance of 120 m from the kiln were found to be 54.3 ± 11.3 Bq kg〈sup〉−1〈/sup〉, 62.1 ± 18.2 Bq kg〈sup〉−1〈/sup〉, and 572 ± 123 Bq kg〈sup〉−1〈/sup〉, respectively; the levels show further decreasing trend in all directions (towards and away from the kiln). Associated radiological hazard indices were calculated in order to assess the radiation effects to human health and compared with the world-recommended values. Basic multivariate statistical analysis was performed to describe the statistical characteristics of the radionuclides. Lower values of radiological indices indicate that there is no probability of immediate health effect on workers and public living around the kiln due to the presence of natural radioactivity in the agricultural soils.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The electrical conductivity (EC) is one of the main characteristics of river water quality, and its prediction is important for river water quality management. The simple regression models are widely used in water and environment studies and can be used for EC prediction when there are limited recorded data. The statistical improvement methods can be used to improve the accuracy of the simple regression models. The objectives of this study are the improvement of the prediction of EC of river flow based on river flow discharge data. Statistical methods include different combinations of logarithmic and inverse transformation with conventional simple linear and non-linear and novel segmented linear models used to improve EC prediction. Two data sets belonging to Zarringol and Ramian station located in northern Iran are used and root mean square error (RMSE) and mean bias error (MBE) are selected to analyze the results. The results show underestimation behavior for investigated combinations of models and transformations. The logarithmic transformation has an improvement effect while inverse transformation decreases the accuracy of models. The segment linear model, due to its ability to fit on the non-monotonic behavior of data, provides better results than other studied simple linear and non-linear regression models. Finally, it is clear that the combination of logarithmic transformation and segmented linear model leads to the best improvement among different combinations of examined statistical improvement methods.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study has described detailed lithofacies analysis, clay mineralogy, and depositional setting, and highlighted economic mineral potential of late Miocene to Early Pliocene mid Siwalik Dhok Pathan Formation. The Siwalik fluvial sedimentary succession is 5300 m thick in the NW Himalayan foreland fold-and-thrust belt known as Surghar-Shingar Range (SSR). The middle Siwalik (Dhok Pathan Formation) typically represents cyclic alternation of massive sandstones, siltstones, mudstones, and claystones in repeated fining upward rhythm with varied thicknesses from 807 to 1540 m. Detailed sedimentological investigations resulted in the identification of seven distinct lithofacies (Gt, St, Sh, Ss, Sl, Fm, and Fl) which had been deposited by sand-dominated bed load braided fluvial system. The facies Sh is hosting detrital uraninite identified through a scanning electron microscope (SEM). X-Ray diffraction analyses revealed that kaolinite, smectite (montmorillonite and saponite), illite, vermiculite, and chlorite (clinochlore and chamosite) are the main clay mineral suits present in the formation. The morphology of clay mineral suits is indicative of weathering products or contribution from the source areas. The absence of glass shards and mineral analcimolite evidenced that these smectite group clay minerals were not derived from the devitrification of volcanic ashes. The sedimentological analysis, mineralogical composition, and paleo-flow directions revealed that these sediments had been deposited by NS fluvial system presently known as Indus River system in this area. The rare earth element concentrations of sandstone and heavy minerals laminations (black sand) show enrichment of uranium (662 ppm), thorium (1374 ppm), La (975 ppm), Ce (2831 ppm), Pr (193 ppm), Nd (746 ppm), Gd (98 ppm), and Dy (50.8 ppm), which specify good indicative economic mineral potential of the formation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper presents the results of comprehensive evaluation of Pléiades 1A which is the first civilian satellite of Europe with sub-meter resolution. The analyses consist of radiometric evaluation, georeferencing accuracy assessment, pan-sharpening performance, digital surface/terrain model quality and vector map production. The effective resolution is estimated with a factor slightly below 1.0 for triplet panchromatic images, and signal to noise ratio is in the range of other comparable space borne images. The georeferencing accuracy was estimated with a standard deviation in X and Y directions in the range of 0.45 m by bias-corrected and sensor-dependent rational functional model. 3D standard deviation of ± 0.44 m in X direction, ± 0.51 m in Y direction and ± 1.82 m in the Z direction were reached in spite of the very narrow angle of convergence by the same mathematical model. The generated digital surface/terrain models were achieved with ± 1.6 m standard deviation in Z direction in relation to a reference digital terrain model. The pan-sharpened images were generated by various methods, and were validated by quantitative and qualitative analyses. Moreover, a vector map was generated in the level of detail 0 to analyse information content.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this study, the trend of precipitation and river flow rate changes in Lake Urmia basin (LUB) were investigated at two monthly and annual scales using the modified Mann-Kendall test (MMK) with complete removal of autocorrelation process. To this purpose, 42 rain gauge and 25 hydrometric stations were selected in Lake Urmia basin during the statistical period of 1984–2013. The results of studying the precipitation changes in the LUB indicated that this basin experienced a combination of decreasing and increasing trend during the studied statistical period. The decreasing precipitation trend was often observed at west and southwest stations of the basin. The increasing trend was observed in the southern and northeastern regions. The results of studying the changes in river flow rate of the studied stations in the LUB indicated that the trend of river flow rate is decreasing in most of the months. At an annual scale, the decreasing trend of river flow rate was also clearly observed across the basin at all stations. In addition, the decreasing trend of river flow rate is more severe in autumn and winter. The results of studying the time of changing point in the precipitation series showed that the time of changing point occurred between 1992 and 1998 at most of the stations that experienced a decreasing precipitation trend. The time of changing point of river flow rate in LUB occurred between 1994 and 1998. Two years after the reductions in precipitation, the decreasing trend of river flow rate occurred in the rivers.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Tests of rock strength under different loading rates and stress paths often lead to ambiguous results, as both factors are inter-playing each other. As a result, there is surprisingly little research into the study of unifying both factors when comparing the rock strengths from various triaxial compression tests. In this technical note, we propose a simple but rigorous mathematics expression to assess and compare the rock strengths under different loading rates and stress paths. To make the proposed method as accessible as possible to a broad application, we have derived the explicit forms of solutions for three popular rock failure criteria. We then examine and validate the proposed method using the results of triaxial tests on marbles and sandstones, based on the important Mohr-Coulomb criterion.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Soil amendments, such as compost and biochar are known to affect soil properties, soil microbial activity, and plant growth. These organic amendments have the ability to increase soil fertility, carbon sequestration, and crop productivity. However, there is limited information available on the integrated application of biochar and compost on microbial and enzymatic activity, nutrients availability and plant growth in arid soil. The present study was designed to quantify the effect of biochar along with compost on soil microbial biomass (carbon, nitrogen, phosphorus), enzyme (urease, alkaline phosphatase, dehydrogenase) activity, nutrients (N, P, K) availability in soil, and plant growth. The treatments comprise a control, biochar at 20 g kg〈sup〉−1〈/sup〉 soil, compost at 20 g kg〈sup〉−1〈/sup〉 soil, biochar + compost at (10 g kg〈sup〉−1〈/sup〉 soil + 10 g kg〈sup〉−1〈/sup〉 soil), biochar + compost at (15 g kg〈sup〉−1〈/sup〉 soil + 5 g kg〈sup〉−1〈/sup〉 soil), and biochar + compost at (5 g kg〈sup〉−1〈/sup〉 soil + 15 g kg〈sup〉−1〈/sup〉 soil). Tomato was grown as a test plant in the pot experiment. The results revealed that biochar and compost alone or in combinations proved statistically significant for Soil pH. Application of biochar at 20 g kg〈sup〉−1〈/sup〉 soil proved useful and increased (130%) microbial biomass carbon (MBC) as compared with control. Compost at 20 g kg〈sup〉−1〈/sup〉 soil increased alkaline phosphatase (143%), urease activity (10%) and plant nitrogen (33%) over control. However, microbial biomass nitrogen (MBN), and dehydrogenase activity increased by 62, and 100% respectively in the treatment receiving biochar and compost at 10 + 10 g kg〈sup〉−1〈/sup〉 soil compared to that in the control. Plant phosphorus and potassium contents were 34 and 70% higher in the treatment receiving biochar and compost at 5 + 15 g kg〈sup〉−1〈/sup〉 soil than in the control. However, for plant parameters (plant height, plant fresh weight, and plant dry weight), the combination of biochar and compost at 15 + 5 g kg〈sup〉−1〈/sup〉 soil was superior to other treatments.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Bangong-Nujiang suture zone lies in the central part of the Tibetan Plateau. It is not only an important plate suture zone, which has direct controlling effect on magmatic activities and tectonic evolution of South Qiangtang and North Gangdese, but it is also an important metallogenic belt. Its tectonic evolution is closely related to the evolution history of the whole Tibetan plateau. In this paper, zircon U-Pb dating of the acid intrusive rocks in Lhaguo Tso has been conducted. Chronologically, the rock types are medium-fine-grained granodiorite (γδ〈sup〉a〈/sup〉K〈sub〉1〈/sub〉) → medium-grained granodiorite (γδ〈sup〉b〈/sup〉K〈sub〉1〈/sub〉) → fine-grained biotite adamellite (ηγβ〈sup〉a〈/sup〉K〈sub〉1〈/sub〉) → medium-fine-grained biotite adamellite (ηγβ〈sup〉b〈/sup〉K〈sub〉1〈/sub〉). The formation time ranges from 113.7 to 100.3 Ma, and the magmatic activity is concentrated in Lower Cretaceous, coincided with the Lower Cretaceous magmatism of the Northern Gangdese terrane. The intrusive rocks in the research area are characterized by high silica (SiO〈sub〉2〈/sub〉 = 59.96~78.03%), potassium-rich (K〈sub〉2〈/sub〉O = 2.04~4.71%), alkali-rich (K〈sub〉2〈/sub〉O + Na〈sub〉2〈/sub〉O = 6.08~8.5%), peralkaline to peraluminous (A/CNK = 0.89~1.25), and high calc-alkaline to shoshonitic. The intrusive rocks in each stage are obviously enriched with LREE and high field elements (such as Th, Ta, Hf), and relatively depleted large ion lithophile elements (such as Ba, K, Sr). Total REE ranges from 82.53 × 10〈sup〉−6〈/sup〉 to 203.91 × 10〈sup〉−6〈/sup〉, with LREE/HREE of 82.53 × 10〈sup〉−6〈/sup〉~203.91 × 10〈sup〉−6〈/sup〉, (La/Sm)〈sub〉N〈/sub〉 of 1.68~14.77, (Gd/Yb)〈sub〉N〈/sub〉 of 0.92~1.84, and middle negative Eu anomalies (δEu = 0.07~0.94). Based on the above discussions, we propose that the geochemical characteristics of these intrusive rocks are consistent with those of arc-type magmas worldwide. Comprehensive research shows that Lhaguo Tso intrusive rocks in the Bangong-Nujiang Tethys ocean crust of southward subduction background, formed in a typical island arc tectonic background, suggesting that the Bangong-Nujiang ocean in the Lower Cretaceous (113~100 Ma) is still under the southward subduction of the Northern Gangdese terrane, may not have been closed.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Synthetic resistivity and chargeability models are employed to study the electrode array and data density effects in inversion resolution for 3D induced polarization tomography. Results from the inversion tests with different electrode arrays illustrate that the inversion resolution for electrical resistivity tomography (ERT) and induced polarization tomography (IPT) data with the dipole–dipole array perform better than the pole–pole array and pole–dipole array. In addition, the anomalous bodies with high impedance and high chargeability are hard to be reconstructed. In contrast, the ones with low resistivity and high chargeability can be well established. Results from the inversion tests with different data densities illustrate that the higher data density will yield better inversion resolution for the ERT and IPT data. We firstly employ the sensitivity analysis method and depth of investigation (DOI) index method to evaluate the inversion results. Then, we present the observation-to-parameter ratio (〈em〉OPR〈/em〉) and model-drift ratio (〈em〉MDR〈/em〉) for discussing and evaluating the quality of the inverted maps, and the result shows that the correlation can reach to the limit when the data density reaches a certain 〈em〉OPR〈/em〉 value of 44. Results from the synthetic inversion tests generally provide reference and guidance for employing the measuring electrode with a suitable arrangement and reasonable number in the field ERT and IPT surveys. Lastly, IPT method with dipole–dipole array has been employed in the mining area with the better prospect of mineral exploration northwest of Gansu Province, China. Moreover, the inverted maps reveal three ore bodies with high resolution.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Biomaterials have been used to replace or support the human organs or tissues in many years. Titanium and its alloys are metallic biomaterials which bond strongly with bone and are compatible with the surrounding tissue. Hydroxyapatite (HAp:Ca〈sub〉10〈/sub〉(P0〈sub〉4〈/sub〉)〈sub〉6〈/sub〉(OH)〈sub〉2〈/sub〉) is a calcium phosphate–based bioceramics and mostly used in coating of metallic biomaterials. In this study, HAp and bioactive glass powders were successfully prepared by sol-gel method. Diatomite, quartz sand, and bioactive glass were selected as SiO〈sub〉2〈/sub〉 sources. Then, different SiO〈sub〉2〈/sub〉 source–added HAp bioceramics were coated on Ti6AI4V metal substrate by HVOF method. Then, the characterization of the coatings was investigated. Thermal analysis of HAp powders was characterized by using TG-DSC. Mineralogical analysis of the coating material was performed by using XRD. Thicknesses and morphological analysis of the coating were done by SEM. According to the TG results, the total weight loss of HAp powers is 11.44% in the 100–1000 °C range. The characteristic peaks of HAp (2θ = 26° and 32°) were observed for pure HAp and doped HAp powders. Tricalcium phosphate (TCP) as secondary phases was detected in doped HAp powders. Pure HAp coating thickness was 186 μm. The thickness of coating decreased with additive as pure HAp.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉It is difficult to quantitatively assess the response of hydrological drought (HD) to climate change in the inland river basins of northwest China because of the complicated geographical environment and scarce data. To address this problem, we conducted a hybrid model by integrating the ensemble empirical mode decomposition (EEMD), the long short-term memory (LSTM) model, and the statistical downscaling method and selected the Aksu River Basin (ARB) as a typical representative of data-scarce inland river basin in northwest China to simulate its hydrological drought in the period of 1980–2015 based on reanalysis climate data and hydrological observation data. The coefficient of determination (〈em〉R〈/em〉〈sup〉2〈/sup〉), the mean absolute error (MAE), the Nash–Sutcliffe efficiency coefficient (NSE), and the index of agreement 〈em〉d〈/em〉 (〈em〉d〈/em〉 index) all showed high simulation accuracy of the hybrid model (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.712, MAE = 0.304, NSE = 0.706, and 〈em〉d〈/em〉 index = 0.901 of the Aksu River Basin), and the simulated effect of the hybrid model is much better than that of a single long short-term memory model. The simulated results in the Aksu River Basin by the model revealed that hydrological drought in the two subbasins (i.e. the Kumarik River Basin (KRB) and the Toshkam River Basin (TRB)) showed similar cycles on the seasonal scale, the interannual scale, and the interdecadal scale, which are mainly controlled and influenced by regional climate change. On the seasonal scale, the effect of precipitation and temperature on hydrological drought is not significant; on the interannual scale, precipitation is the key factor compared to temperature in inducing hydrological drought change; on the interdecadal scales, the correlations between precipitation, temperature, and hydrological drought were the strongest and most significant.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Our study focuses on the interpretation of wire-line logs to evaluate the hydrocarbons potential of sandstone reservoir in the Kadanwari gas field, Sindh, Pakistan. We have considered wire-line logs of four drilled wells (K-01, K-03, K-10, and K-11) in the research area and interpreted 13 reservoir zones. Analytical reservoir analysis includes the shale content (〈em〉V〈/em〉〈sub〉sh〈/sub〉), effective porosity (Ø〈sub〉eff〈/sub〉), hydrocarbon and water saturation (〈em〉S〈/em〉〈sub〉hc〈/sub〉 and 〈em〉S〈/em〉〈sub〉w〈/sub〉), and net pay thickness variations. Hydrocarbon-bearing zone characterized by high resistivity values, porosity high, permeability high, saturation of water low, and less 〈em〉V〈/em〉〈sub〉sh〈/sub〉 suggest clean sand. The petrophysical analysis revealed the hydrocarbon potential of lower Goru sandstone packages at different levels (2886–3797 m). The petrophysical parameters of sub-reservoirs were carefully analyzed which are ranked as good quality sand reservoirs with average effective porosities ranging from 0.11–0.44%, average water saturation ranging from 0.18–0.45%, hydrocarbon saturation averaging between 0.59–0.86%, and permeability ranging from 10.539 to 477.76 m Darcy. Water saturation for heterogeneous shaly sand reservoirs was successfully tested by Indonesian model which suggests that 〈em〉S〈/em〉〈sub〉w〈/sub〉 in each well is fewer than 60% therefore over all the region bearing good quality of hydrocarbon potential of the targeted formation and selected zones. The vertical and horizontal variations of reservoir parameters are studied through constructing the litho-saturation cross-plots and isoparametric maps of the petrophysical parameters, respectively. The isoparametric maps help to visualize the geographical distribution of reservoir configuration in the subsurface. The petrophysical estimates of this study appraise the national conventional fuel treasure of lower Goru formation in Kadanwari gas fields and suggest new prospects to drill more wells on the central portion of the southwestern part of the study area. The neighboring area to the south of Kadanwari-01 is economically viable for hydrocarbon exploration. The northeastern side of the study area is avoided due to the high concentration of water and excessive shale content.〈/p〉