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Enhancing multispectral remote sensing data interpretation for historical gold mines in Egypt: a case study from Madari gold mine
摘要： In the last decade, most of the outcrops around the historic gold mines in Egypt had been damaged by the local miners, a situation that complicated remote sensing-based exploration research activities. Madari gold mine area was no more fortunate than other mines in the region. This study identifies a new integrated remote sensing workflow that emphasizes the spectral variations related to differences in chemical and mineralogical compositions of the investigated rock units and deemphasizes the spectral variations introduced by the local miners. All combinations of ratio images are first generated from Landsat 8 Operational Land Imager (OLI) data, then a suite of ratio images that best differentiates between the investigated units is selected, and finally the selected ratio images were stacked to substitute the original image bands in the further processing techniques. The PCA was then applied to the selected ratio images within the stack. Subsequently, a statistical analysis of the eigenvector matrix for each of the PC bands was conducted to select the optimum PC bands and a Principal Component False Color Composite image (PC-FCC) was created from the three selected PC bands. The PC-FCC image (PC3, PC11, PC4 in RGB) was chosen as a result of subtracting the average PC eigenvector negative weights from the average positive eigenvectors weights. Not only was the PC-FCC image used to distinguish the main rock units in the damaged area, but also, to identify the areas with intense alteration zones.
关键词： Eastern Desert,Principal component analysis (PCA),Landsat 8 (OLI),Madari gold mine,Egypt,Ratio images
更新于2025-09-23 15:23:52
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Improving direct normal irradiance retrieval in cloud-free, but high aerosol load conditions by using aerosol optical depth
摘要： Measurements of the global surface solar irradiation and its direct and diffuse components performed at three Egyptian sites (Aswan, Cairo, and Port Said) are used to test the ability of two published decomposition models to estimate the hourly direct normal irradiance from the measured global horizontal one in cloud-free conditions. The tested models failed to reproduce the temporal variability of the measurements, which we show to be partly induced by the large variability of the atmospheric content in aerosols. We propose a revised formulation of the decomposition models that takes into account the aerosol optical depth (AOD) at 1000 nm derived from onsite measurements. It leads to a significant reduction of the bias and root mean square deviation of the original models and this at the three Egyptian sites. However, because the AOD is rarely measured at the meteorological stations, we also quantify the performance of the revised models when the AOD is either derived from the MODIS observations or obtained by the products from Copernicus Atmospheric Monitoring Service (CAMS). Probably because of their finer temporal resolution that makes them more apt to reproduce the rapid variations of the AOD, the best results are obtained with the CAMS products. Therefore, we recommend using a combination of the revised decomposition models and these CAMS products to estimate the hourly direct normal irradiance in areas such as Egypt where aerosols are ubiquitous. Note that the improved decomposition models are generally applicable in all-sky conditions, although their benefit has been demonstrated to be significant, and probably limited to, cloud-free conditions.
关键词： Egypt,Direct normal irradiance,Aerosols,MENA
更新于2025-09-23 15:22:29
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Spatial modeling for the optimum site selection of solar photovoltaics power plant in the northwest coast of Egypt
摘要： The unbalanced distribution of the Egyptian population causes serious social and economic problems. Redistributing population density to fully utilize the uninhabited areas like desert regions is very critical. This requires discovering renewable energy and water resources, to achieve an optimal goal of the sustainable national strategy. Therefore, this paper aims to define the most suitable locations for establishing the photovoltaic (PV) power plants considering the techno-economic and environmental conditions, assuring the maximum power achievement with minimizing project cost. To achieve this, the integration of Geographic Information System (GIS) tools, Remote Sensing technology (RS) with the Multi-Criteria Decision Making (MCDM) technique was performed. Among MCDM techniques, the Analytic Hierarchy Process (AHP) method has been used to determine the weights of the multi-criteria (techno-economic and environmental) as a more suitable tool to solve site selection problems. The obtained results showed that the entire region's surface receives a large amount of radiation, as the maximum and the minimum values of solar radiation for 2018 were 5.9 - 4.7 kWh/m2/day, respectively. The Land Suitability Index (LSI) map was created to evaluate the potentiality of the sites. LSI was classified into five categories: “most suitable,” “highly suitable,” “moderately suitable,” “marginally suitable,” and “least suitable”. As a result, 24.9 % (261.1747 km2) of the investigation area is more suitable and promising for deploying photovoltaic (PV) power plants.
关键词： Multi-Criteria Decision Making,Egypt,Photovoltaics power plants,GIS,Remote Sensing
更新于2025-09-23 15:21:01
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Rapid determination of mercury in dust emission using Cold Vapour Inductively Coupled Plasma Optical Emission Spectrometer (CV ICP OES)
摘要： Mercury emissions generated by the human activities were ranged between 60% and 90% from total mercury content determined in some industrialised regions. It is well known that urban dust has adverse health effects, being related to respiratory diseases. In this study, Cold Vapour Inductively Coupled Plasma Optical Emission Spectrometer (CV ICP OES) was optimised, validated, and applied in routine analysis for the determination of vapour mercury in dust emission samples collected from different Egyptian cement plants. The estimated detection limit, practical quantification limit, linearity (linear dynamic ranges and method linearity), accuracy (trueness and precision), and measurement uncertainty parameters were studied under optimised (CV ICP OES) conditions. The method showed that the estimated detection limit was found to be equal to 0.12 μg/L, and the quantification limit was found to be equal to 0.5 μg/L. The mean recoveries ± standard deviations at different levels were varied between 88.60 ± 8.18 and 110.20 ± 5.93% with a coefficient of variation expressed as relative standard deviation ranged from 0.64 and 7.25%. The method trueness was confirmed by using four different certified references materials purchased from Food Analysis Performance Assessment Scheme (FAPAS) and all obtained results were within satisfactory ranges and had acceptable recovery and Z-score values. The method precision, in terms of relative standard deviation (RSD), was being below 7.74%. The method uncertainty expressed as expanded uncertainty was found to be ≤ 16.11%. The results obtained make the method suitable for accurate determination of vapour mercury in dust emission samples at low concentration. The validated method was used for the determination of mercury in fifty-eight dust emissions samples and the results were compared with the maximum limit stated by European standard on the incineration of waste.
关键词： CV ICP OES,cement plants,mercury,Method validation,Egypt
更新于2025-09-19 17:13:59