Prehliadanie podľa Autor "Ekwok, Stephen Eguba"

Teraz sa zobrazuje 1 - 5 z 5
  • Obrázok miniatúry
    Položka
    Delineating pixels of natural hydrocarbon micro-seepage induced alterations and anomalies in overlying soils and sediments in ugwueme, with ASTER data and band ratio technique
    (Hard : Olsztyn, 2024) Enoh, Mfoniso Asuquo; Augustine, Ojanikele Willie; Chiemelu, Ndukwe Emmanuel; Ekwok, Stephen Eguba; Akpan, Anthony E.; Eldosouky, Ahmed Mohammed; Alarifi, Saad S.; Andráš, Peter
    The earth’s underlying hydrocarbon-bearing reservoirs frequently leak. These reservoirs leak because of their inadequate sealing, and at high pressure, oil and gas escape vertically or nearly vertically to the earth’s surface as seepage. Micro-seepages on the earth’s surface cause oxidationreduction reactions, which cause anomalies in the soils and sediments beneath them. Remote sensing (RS) and geographic information systems (GIS) are important tools for investigating hydrocarbon micro-seepage-induced changes and anomalies in overlying soil and sediments. In this study, ASTER remote sensing data was adopted to delineate pixels of hydrocarbon micro-seepage-induced anomalies in Ugwueme, south-eastern Nigeria. Band Ratio (BR) was used as a spectral enhancement technique to detect alterations and anomalies in the overlying soil and sediments. ASTER BR of 2/1 improves ferric iron; (5+7)/6 improves clay minerals; (1+4)/(2+3) improves ferrous iron; and 4/(6+9) improves gypsum. The study highlights that BR is an excellent spectral enhancement technique for delineating areas of alterations and anomalies induced by hydrocarbon micro-seepage.
  • Obrázok miniatúry
    Položka
    Mapping of geological structures and sediment thickness from analysis of aeromagnetic data over the Obudu Basement Complex of Nigeria
    (Oxford University Press, 2024) Ekwok, Stephen Eguba; Eldosouky, Ahmed Mohammed; Thompson, Edward A.; Ojong, Romeo Akombi; George, Anthony M.; Alarifi, Saad S.; Kharbish, Sherif; Andráš, Peter; Akpan, Anthony E.
    In this study, geologic structures, as well as attendant orientations and sediment thickness, in the Nigerian Obudu Complex were delineated using the Centre for Exploration Targeting (CET), and depth determination methods such as source parameter imaging (SPI) and standard Euler deconvolution (SED). The CET, SPI, and SED procedures were applied on the total magnetic intensity data. Also, the enhanced TMI data using analytic signal, first-vertical derivative, total-horizontal derivative, and tilt-angle derivative filters were further subjected to CET operation, with the aim of mapping both subtle and prominent lineaments. In general, mapped geologic structures trends in the NE–SW, NNE–SSW, E–W, and N–S directions. Overall, the dominant geologic structural orientations of NE–SW and NNE–SSW reflect the regional strike orientation. The regional striking of the lineation, which is caused by the Pan-African orogeny and subsequent post-orogenic processes, has an impact on these orientations. The N–S and E–W structural deviations from the main NE–SW and NNE–SSW trends are initiated by the YGS of the post-orogenic events. Overall, these complex geologic structures are probable sites for metallogenic minerals.
  • Obrázok miniatúry
    Položka
    Solar PV systems under weather extremes: case studies, classification, vulnerability assessment, and adaptation pathways
    (Elsevier : Amsterdam, 2025) Okonkwo, Paul C.; Nwokolo, Samuel Chukwujindu; Udo, Sunday; Obiwulu, Anthony Umunnakwe; Onnoghen, Usang Nkanu; Alarifi, Saad S.; Eldosouky, Ahmed M.; Ekwok, Stephen Eguba; Andráš, Peter; Akpan, Anthony E.
    This study examines the significant challenges presented by the rising frequency and severity of climate changeinduced extreme weather events-such as hurricanes, floods, heatwaves, and snowstorms-on the reliability and efficacy of solar photovoltaic (PV) systems. Utilizing case studies from various global places, it underscores the susceptibilities of photovoltaic systems to environmental harm, encompassing structural failure, efficiency decline, and operational interruptions. The study presents a novel, resilience-oriented paradigm that incorporates sophisticated design principles, operational techniques, and policy innovations to alleviate these risks. Principal findings underscore the significance of site-specific risk evaluations, modular and adaptable system architectures, and cohesive resilience planning in photovoltaic system engineering. Proactive operational techniques, such as regular maintenance, emergency reaction plans, and intelligent system monitoring, are deemed essential for sustaining performance in extreme weather conditions. Innovative technological solutions, including resilient materials, sophisticated coatings, durable mounting methods, and thermal management technologies, are emphasized for their capacity to endure intense environmental stressors. The study delineates future research goals, encompassing the creation of innovative materials with superior durability, scalable energy storage integration, structural advances, and greater grid interconnectivity via smart grid technology. It emphasizes the significance of cybersecurity protocols to safeguard photovoltaic infrastructure and promotes legislative and regulatory enhancements to facilitate resilience implementation. Collaboration among researchers, industry executives, and policymakers is considered crucial for addressing the increasing difficulties presented by climate change. This paper establishes a framework for integrating resilience into all facets of solar PV system design and operation, thereby ensuring the long-term sustainability, efficiency, and efficacy of solar energy systems in a swiftly changing climate environment. This comprehensive strategy is essential for ensuring the future of renewable energy amid global environmental difficulties.
  • Obrázok miniatúry
    Položka
    Spatial analysis of leachate penetration at Lemna dumpsite, Calabar: Implications for sustainable waste management in Cross River State
    (Elsevier B.V. : Amsterdam, 2024) Igelle, Evaristus Idaga; Phil-Eze, Philip Ogbonnia; Akim, O. Okang; Kanu, H. Izuakolam; Ekwok, I. C.; Atsa, Joy William Undie; Ojugbo, P. A.; Okputu, Joseph S.; Abdelrahman, Kamal; Ekwok, Stephen Eguba; Andráš, Peter; Eldosouky, Ahmed Mohammed
    This study rigorously investigated the spatial analysis of leachate penetration at Lemna dumpsite, located in Calabar, Cross River State, Nigeria. Purposeful soil sampling, performed at specific intervals (5 m, 25 m, and 50 m) along the Electrical Resistivity profile line within the dumpsite, was augmented by water sample collection from five boreholes near Lemna dumpsite. Utilizing Electrical Resistivity Tomography (ERT) and Vertical Electric Sounding (VES) survey techniques, resistivity data were systematically gathered to comprehensively analyze the Leachate Penetration in the Lemna dumpsite. Laboratory analysis of soil and borehole water quality focused on Benzene, Toluene, Ethylbenzene, and Xylene (BTEX), with paired sample t-tests applied for statistical scrutiny. Analyzing the ERT and VES data employed sophisticated techniques embedded in Resistivity Two Dimension Invasion software and Advanced Geosciences Incorporation Earth Imager software. Substantial disparities (p < 0.05) emerged in the paired sample t-tests for BTEX in soil compared to National Environmental Standard Regulation and Enforcement Agency (NESREA) limits. Similarly, BTEX in borehole water displayed significant differences (p < 0.05) when compared to World Health Organization (WHO) standards, raising alarming concerns about the safety and portability of groundwater in the area. The examination of dumpsite leachate penetration revealed a resistivity anomaly of 8.01 Ωm and an inverse depth of 12.4 m, underscoring profound environmental implications and necessitating immediate remediation efforts. Additionally, Vulnerability and Aquifer Protective Capacity Index (VES) results, with a rating of <0.1, indicated severely compromised aquifer protective capacity, emphasizing the vulnerability of groundwater resources to further contamination. Our study advocates for strategic management, remediation, and monitoring measures to prevent contamination and safeguard water quality in the region.
  • Obrázok miniatúry
    Položka
    Unveiling the mineral resources and structural patterns in the Middle Benue Trough: a comprehensive exploration using airborne magnetic and radiometric data
    (Taylor & Francis Group : Abingdon, 2024) Ekwok, Stephen Eguba; George, Anthony M.; Omori, Asuquo A.; Abdelrahman, Kamal; Ugar, Samuel Izama; Andráš, Peter; Morphy, Morod Iwong; Akpan, Anthony E.; Eldosouky, Ahmed Mohammed
    The Middle Benue Trough (MBT) in Northcentral Nigeria is a geologically significant area with vast mineral resource potential. Employing airborne magnetic and radiometric data, this study utilized the Centre for Exploration Targeting on enhanced total magnetic intensity data to reveal geologic structures, lithological units and mineralization zones. Lineaments predominantly trended in NE-SW direction, with noteworthy orientations in NNE-SSW and E-W. Radiometric anomalies correlated with distinct lithological units, pinpointing granitic gneiss, alluvium, shale, siltstone and sandstone. A magnetically concentrated and potassium-rich area indicated potential polymetallic-magnetic mineralization. The 2D model illustrated igneous intrusions influencing prevalent geologic structures, such as sediment baking and doming. Thorough analysis, including source parameter imaging, standard Euler deconvolution and 2D forward modelling, revealed sediment thicknesses below 1500 m. This research enhances understanding of the MBT’s geological features, offering valuable insights for mineral exploration and resource assessment in the region.