Arabian Journal of Geosciences最新文献

Overburden dumping is an important issue in consideration of economy and safety for surface mining of coal. The higher slope angle and increased dump height improve the economic benefits, however decrease the stability of the dumps. Dumping methods are classified as (i) end-tipping method and (ii) paddock-dumping method. However, the stability analysis models practised for both the cases are same. The dump slope stability models consider internal friction angle, cohesion and some other properties as the essential parameters affecting the stabilising and destabilising forces. These parameters are significantly changes with the types and sizes of the rock materials. While the dumping methods are different, these properties are changing at different depths of dump. This consideration is missing in the current dump slope stability modelling. This paper focusses on the comparative analysis of stability achieved by forming an overburden dump by an end-dumping approach as well as the paddock approach. From a dump stability analysis, it is found that end dumping exhibits a better factor of safety up to a dump height of 90 m (3 benches of 30 m each) and paddock dumping exhibits better factor of safety than the end-dumping method beyond that and up to a dumb height of 150 m. The paddock-dumping method poses a better factor of safety as compared to the end-dumping method as the number of benches goes up. The reason for higher safety factor in paddock dumping as compared to end dumping may be attribute to the better size distribution and compaction due to machine movements.

Geothermal energy in shallow depth is a locally generated, inexpensive, green renewable energy source. It has proven to be a desirable alternative to fossil fuels for building heating and cooling systems. Horizontal ground heat exchangers (HGHE) coupled to a ground source heat pump are among the shallow geothermal systems. The objective of this study is to investigate the thermal performance of a horizontal U-shaped geothermal heat exchanger for heating and cooling buildings in a region located in northwestern Algeria. Therefore, a three-dimensional transient numerical model based on the finite element method is established using COMSOL multiphysics software. The atmosphere-soil-HGHE interaction and moisture transfer in unsaturated soils are taken into account in this modeling. The effect of pipe length and fluid flow velocity on the performance of horizontal geothermal heat exchangers is also highlighted by this work. The study’s main findings indicate that the heat exchanger’s thermal capacity in summer is approximately 18.11% higher than in winter. This is due to a larger temperature difference between the inlet and outlet water in summer (2.31°C) compared to winter (1.72°C), improving the heat exchanger’s efficiency during summer. The long heat exchange tube is intended to enhance heat transfer. However, the effectiveness of the HGHE is adversely affected by the fact that as fluid velocity rises.

Technological Accidents Triggered by Natural Events (Natech) incidents are occurring more frequently worldwide, driven by rapid industrialization, climate change, and human-induced risks. Understanding all the dynamics of Natech risk is highly complex. Frequently, interactions between multiple hazards are disregarded. Studies have primarily focused on individual natural hazards, examining the most common damage scenarios, resulting in a recurring research cycle in Natech studies and potential oversight of other natural hazards (risk myopia). Sinkholes are becoming an increasing threat to industries every year, with the potential to escalate. Moreover, this hazard can also be triggered by anthropogenic stressors. The sinkhole threat needs to receive adequate attention in Natech research. Another threat, induced seismicity caused by anthropogenic activities, needs to be sufficiently addressed in the risk assessment of Natech accidents. The focal industries of Natech research include the storage, chemistry, and petrochemical sectors. The need for studies in the manufacturing industry (glass, metal, casting, textiles, furniture, automotive) underscores a gap in the literature. This study aims to present an argument that is both different and supportive of prevailing approaches in the literature by drawing attention to anthropogenic activities, often overlooked in the analysis of technological accidents triggered by natural hazards, the presence of potentially dangerous natural events, and industrial sectors that have been either wholly overlooked or the subject of limited research.

In this study, the interaction parameters of gamma rays in six heavy metallic glass samples with densities ranged from 2.43 to 4.373 g/cm³. Phy-X/PSD program were used to estimate gamma radiation interaction parameters in the energy range (0.015–15) MeV. The outcomes of this research showed that the linear attenuation coefficient (LAC) increased with increasing sample density, at 0.015 MeV gamma energy, the LAC were reported as 151.895, 122.761, 81.294, 75.504, 22.041, and 19.266 cm⁻¹ for the glasses BTC1, BTC2, PZCNF2, PZCNF1, PKFC2, and PKFC1, respectively. Similar to the linear attenuation coefficient (LAC), the mass attenuation coefficient (MAC) was also calculated. As the energy of the incident photon increases, the half-value layer (HVL), the tenth-value layer (TVL), and the mean free path (MFP) increase. The higher value of Z_eff has superior radiation shielding capability. For all thicknesses, the glass samples had the lowest transmission factor (TF) magnitudes in the low-energy region. The study emphasizes the significance of density in influencing shielding properties and concludes that BTC1 metallic glass exhibits the maximum shielding ability against gamma radiations among the investigated glasses.

The earth’s surface constitutes a layer of soil around it which is termed as pedosphere. Soil holds millions of microbes that are involved in improving soil fertility. The increasing use of chemical fertilizers has become a major factor which is deteriorating soil microflora. It has resulted in decreased soil fertility. Soil organisms are involved in a number of processes like cycling of soil nutrients and providing them to plants. They are also involved in volatilization that may lead to nutrient loss. Microorganisms have an important role in carbon, nitrogen, and sulfur transformations, as well as organic matter degradation. They have an impact on the global nutrient and carbon cycle. The soil microflora is also involved in modulating the various physico-chemical properties of soil like pH, moisture, temperature etc. Soil properties and soil microorganisms are highly correlated with each other. The huge diversity of microorganisms in soil also plays a central role in regulating and supporting various ecosystem services. This review highlights the crucial role of different microbes in various nutrient cycling which is one of the major concerns to address the decreasing status of soil nutrients. It also covers various physico-chemical properties which affects soil microbial community and various ecosystem services provided by microbial activity.

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Tsunamis pose serious threats to coastal regions, particularly regions with critical infrastructure. Recent events in the Indian Ocean and Japan have demonstrated the necessity of conducting comprehensive tsunami hazard analyses across regions including Oman which has experienced historical tsunamis generated from Makran Subduction Zone (MSZ). This study seeks to assess the tsunami hazard for Wudam As-Sahil coast in northern Oman using both deterministic and probabilistic approaches, focusing on earthquake-generated tsunamis from the MSZ. The research employs Deterministic Tsunami Hazard Assessment (DTHA) to model worst-case tsunami scenarios and Probabilistic Tsunami Hazard Assessment (PTHA) to estimate wave height probabilities over various exposure times. Numerical models simulate tsunami generation, propagation, and inundation based on historical and hypothetical earthquake events. The DTHA results indicate that maximum tsunami wave heights could reach 3 m. In contrast, PTHA findings suggest a low probability of waves exceeding 1 m. Furthermore, this study identified Mw 7.2 western MSZ scenario as the most hazardous scenario for Wudam As-Sahil coast with potential run-up heights reaching up to 2.7 m. The findings underscore the moderate tsunami risk facing the Wudam As-Sahil coast. The hazard assessments provide valuable insights for disaster preparedness, indicating areas in need of mitigation measures and emergency planning efforts.

The current study is an attempt to use low cost red green blue (RGB) image–based vegetation indices (VIs), obtained from simple RGB camera, in separating six different field crops. To achieve this, sixteen VIs were calculated and used as inputs in different multivariate analysis for separating wheat (Triticum spp), mustard (Brassica spp), cabbage (Brassica oleracea), pigeon pea (Cajanus cajan), brinjal (Solanum app) and chickpea (Cicer arietinum). Based on the classification and regression tree (CART) analysis, the study identified Green Red Ratio Index (GRRI), Color Intensity Index (INT), Color Index Of Vegetation (CIVE) and Woebbecke Index (WI) were statistically significant (p < 0.05) in discriminating six different crops. The results obtained from CART analysis were subsequently compared with discriminant analysis, which showed an accuracy of 96.3% of classifying different crops. Hence, out of 16 indices, the study meaningfully identified four most sensitive VIs that can be used to classify different field crops. The information achieved in this study can help in commercial and scientific decision-making, planning in agribusinesses, and can be an important tool for conducting crop survey at regional scale.

This study investigated the spatiotemporal variation of water cut in the AB reservoir unit of the Zubair Formation at the South Rumaila oilfield in Iraq using petrophysics, geostatistics, and machine learning techniques. The study found that the spatial distribution of petrophysical properties such as porosity, permeability, volume of shale, and unit thickness had little impact on the distribution of water cut. The most important factor was the rates of water injection and oil production. The study also found that the AB unit is homogeneous rather than heterogeneous, and this heterogeneity does not play a crucial role in the evolving water cut across the oilfield. The study of historical water cut data showed that the northern part of the oilfield had a higher water cut than the central and southern areas in 2012. However, as production and injection rates increased, the entire oilfield saw significant increases in water cut. Modeling of water cut using four machine learning algorithms (random forest, cubist, support vector machine, and linear regression) and a multi-layer perceptron deep learning technique showed that the random forest and cubist algorithms were the best in both training and testing stages. The stand-alone models of these algorithms for each well location can be used to quickly and easily predict water cut values throughout the oilfield, providing a way to efficiently manage the AB reservoir unit.

This study investigates the spatial distribution of rainfall in Nigeria, utilizing ground-based rainfall data from 48 weather stations and two long-term satellite-based precipitation products spanning 39 years (1981–2019). Employing statistical techniques and kriging interpolation methods, this study analysed annual and seasonal rainfall patterns. Correlation coefficient was also used to compare areal averages of satellite-based rainfall estimates and ground-based rainfall data in Nigeria and for each of the six eco-climatic regions. Results indicate significant regional disparities, with the Tropical Wet (Mangrove and Swamp) region receiving the highest mean annual rainfall (> 2,300 mm) and the Sahel Savannah experiencing the lowest (< 450 mm). Eco-climatic regions exhibit varying contributions to total annual precipitation, with mangrove swamps and tropical rainforests dominating. Notably, 76.4% of annual rainfall occurs during the June–August and September–November periods, with August witnessing peak precipitation levels. Over Nigeria, there are strong correlations between satellite precipitation estimates (SPEs) and ground data on a monthly and seasonal basis, but the correlations are weaker on an annual scale, especially in Sahel and Montane regions. While SPEs provide reliable short-term rainfall estimates, caution is advised for annual precipitation estimates, particularly in regions with lower correlations. This study highlights the need for more efficient water use methods, with an emphasis on enhanced storage systems, distribution networks, sustainable irrigation practices, and judicious consumption to address rainfall variability. The findings highlight the importance of understanding rainfall distribution for agricultural planning and regional climate assessments. By integrating ground-based and satellite-derived data, this study enhances knowledge of Nigeria's climate dynamics, facilitating informed decision-making and resource management strategies.

In designing suitable support systems and ensuring safe excavation of a tunnel, deformation and block failure assessment around the opening is a crucial aspect of tunneling. In this study, a distinct element modeling approach was employed to evaluate the distribution of failed blocks, failure modes, and displacements of the tunnels to gain insight into support recommendations for the Wabe Hydropower Project in central Ethiopia. For this purpose, three representative numerical models were developed considering different rock mass along the tunnel alignment. Subsequently, the influence region classification technique was introduced, and the models were systematically classified into three distinct regions. This technique enabled the consideration of blocky rock mass as discontinuum through the direct inclusion of field-measured joints with average spacings of 0.2, 0.56, and 1.2 m into a region surrounding the tunnel opening. The simulation results indicated that tunnels in closely jointed rock mass behave anisotropic, with failed blocks following the joint inclinations of N253/72 and N035/79 and exhibiting a tensile failure mode. Tunneling in the fault zone induced a shear failure mode, with a significant distribution of failed blocks aligned in the maximum principal stress direction. However, under low horizontal in situ stress, both shear and tensile failure could exist, with tensile failure affecting the roof and floor. Furthermore, tunnels in closely jointed rock mass are primarily influenced by horizontal displacement, whereas tunneling in fault zones led to both greater horizontal and vertical convergences, with horizontal displacement being more significant. Finally, the obtained results were used to propose support recommendations.