scholarly journals Investigation of Groundwater Potential Using Electromagnetic Method at a Basement Complex Area of University of Abuja, Gwagwalada

2021 ◽  
Author(s):  
Onoka Adokiye ◽  
Mallam Abu
Keyword(s):  
Current Density ◽  
Clayey Soil ◽  
Low Frequency ◽  
Current Density Distribution ◽  
Groundwater Potential ◽  
Groundwater Exploration ◽  
Electromagnetic Method ◽  
The North ◽  
Overburden Material ◽  
Soil Component

The Very Low Frequency Electromagnetic Method (VLF-EM) was used in view of detecting fractured or weathered zones within the University of Abuja Staff Quarters, Gwagwalada, Federal Capital Territory. The VLF -EM data measured along seventeen profiles of 400m at inter profile distance of 25m and interstation separation of 10m were done using the Scintrex ENVI Instrument. The VLF-EM survey revealed features significant to groundwater potential as conductive zones in the Fraser Filter maps and current density pseudosections. Three distinct zones were delineated based on the current density distribution. The fresh basement terrain corresponds to the highly resistive zone with current density value less than -20. The intermediate zone has current density value range of -20 to 25 typical of rocks and soil component which are slightly resistive to slightly conductive and corresponds to the partially saturated units. The third zone is highly conductive with current density value greater than 30 which includes the saturated weathered or fractured basement, fault zones, clay units and saturated sandy units within the study area. The north eastern, north western (profiles 1-8) and some parts of the southern region (profiles 16 and 17) of the study area show higher conductive zones than the central parts of the study area. This survey has helped in detecting sites that are suitable for groundwater exploration by identifying water bearing fractures and weathered zones in the study area. The areas with high conductivity response are areas with conductive overburden material such as clayey soil, saturated soil, water filled fractures and faults or weathered zone within the basement.

scholarly journals Investigation of groundwater potential using integrated geophysical methods in Moloko-Asipa, Ogun State, Nigeria

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
A. A. Alabi ◽  
S. A. Ganiyu ◽  
O. A. Idowu ◽  
A. F. Ogabi ◽  
O. I. Popoola
Keyword(s):  
Geophysical Methods ◽  
Low Frequency ◽  
Sampling Interval ◽  
Groundwater Potential ◽  
Groundwater Exploration ◽  
Protective Capacity ◽  
Southwestern Nigeria ◽  
Industrial Growth ◽  
Geoelectric Section ◽  
Weathered Layer

AbstractWater is essential for livelihood, development, and industrial growth. Its exploration in sufficient quantity is required where it does not freely occur on the surface. This research was aimed to delineate aquifer regions and provide information on the subsurface lithology of Moloko-Asipa Southwestern Nigeria. A combination of eight traverses investigated with very low frequency electromagnetic (VLF-EM) method at 5 m constant sampling interval and ten vertical electrical sounding (VES) were carried out in the survey. Measurements from the VLF-EM survey were processed with Karous and Hjelt filtering to give the resistivity contrast across the selected profiles. The VES data processing involved an automatic approximation of the initial resistivity and thickness of the geoelectric layers with IPI2Win and further filtering by WinResist iteration. Estimation of Dar-Zarrouk parameters was also employed to investigate the aquifer protective capacity of the area. The processed VLF-EM results showed the geology of the area to an average depth of 25 m. The geoelectric section of the VES data revealed minimum of 3 layers from sandy top soil to weathered layer and fresh basement with an average resistivity values of 1,816, 926 and 17,503 Ωm, respectively. The integration of VLF-EM and VES in the investigation revealed that the potential for groundwater exploration in the study area is poor due to the thin nature of the weathered layer and its shallow depth to basement. The aquifer protective capacity of the area was likewise inferred to be poor.

Energy Balance on Current Density Distribution of Cathode Spot in Vacuum Arc

2019 ◽  
Vol 139 (5) ◽  
pp. 302-308 ◽  
Author(s):  
Shinji Yamamoto ◽  
Soshi Iwata ◽  
Toru Iwao ◽  
Yoshiyasu Ehara
Keyword(s):  
Energy Balance ◽  
Density Distribution ◽  
Current Density ◽  
Cathode Spot ◽  
Current Density Distribution ◽  
Vacuum Arc

Contact Current Density Analysis Inside Human Body in Low-Frequency Band Using Geometric Multi-Grid Solver

2020 ◽  
Vol E103.C (11) ◽  
pp. 588-596
Author(s):  
Masamune NOMURA ◽  
Yuki NAKAMURA ◽  
Hiroo TARAO ◽  
Amane TAKEI
Keyword(s):  
Frequency Band ◽  
Current Density ◽  
Human Body ◽  
Low Frequency ◽  
Density Analysis

Automated Measurement of the Spatial Current Density Distribution of Process Electron Beams

Vestnik MEI ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 72-79
Author(s):  
Aleksey S. Kozhechenko ◽  
◽  
Aleksey V. Shcherbakov ◽  
Regina V. Rodyakina ◽  
Daria A. Gaponova ◽  
...  
Keyword(s):  
Density Distribution ◽  
Current Density ◽  
Electron Beams ◽  
Current Density Distribution ◽  
Automated Measurement ◽  
Spatial Current

scholarly journals A Low frequency Southern Sky Survey Using the Mauritius Radio Telescope

2002 ◽  
Vol 199 ◽  
pp. 25-31
Author(s):  
N. Udaya Shankar
Keyword(s):  
Radio Telescope ◽  
Low Frequency ◽  
Fourier Synthesis ◽  
North East ◽  
The North ◽  
Sky Survey ◽  
Correlation Receiver ◽  
Complex Correlation ◽  
Right Ascension ◽  
East West

The Mauritius Radio Telescope (MRT) is a Fourier synthesis instrument which has been built to fill the gap in the availability of deep sky surveys at low radio frequencies in the southern hemisphere. It is situated in the north-east of Mauritius at a southern latitude of 20°.14 and an eastern longitude of 57°.73. The aim of the survey with the MRT is to contribute to the database of southern sky sources in the declination range −70° ≤ δ ≤ −10°, covering the entire 24 hours of right ascension, with a resolution of 4' × 4'.6sec(δ + 20.14°) and a point source sensitivity of 200 mJy (3σ level) at 151.5 MHz.MRT is a T-shaped non-coplanar array consisting of a 2048 m long East-West arm and a 880 m long South arm. In the East-West arm 1024 fixed helices are arranged in 32 groups and in the South arm 16 trolleys, with four helices on each, which move on a rail are used. A 512 channel, 2-bit 3-level complex correlation receiver is used to measure the visibility function. At least 60 days of observing are required for obtaining the visibilities up to the 880 m spacing. The calibrated visibilities are transformed taking care of the non-coplanarity of the array to produce an image of the area of the sky under observation.This paper will describe the telescope, the observations carried out so far, a few interesting aspects of imaging with this non-coplanar array and present results of a low resolution survey (13' × 18') covering roughly 12 hours of right ascension, and also present an image with a resolution of 4' × 4'.6sec(δ + 20.14°) made using the telescope.

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