Earthquake occurrence is primarily controlled by tectonic stress accumulation; however, external processes such as hydrological loading may influence the timing of fault failure. This study investigates the potential relationship between precipitation and seismicity in southeastern Ghana. An updated earthquake catalogue covering the period 1615–2018 was compiled to evaluate spatial and temporal patterns of seismic activity in the Greater Accra region and surrounding areas. For the statistical analysis, annual seismicity data for 1987–2018 were compared with precipitation records obtained from meteorological stations in Accra, Tema, Ada, Ho, and Takoradi. Pearson correlation and time-lag analyses were applied to examine possible associations between rainfall variability and earthquake occurrence. Results show a moderate positive correlation between annual precipitation and seismicity (r = 0.36–0.40), with statistical significance observed at zero-year lag (p = 0.043). This suggests that increased rainfall may contribute to short-term modulation of seismic activity, possibly through pore-pressure changes and hydromechanical stress adjustments along pre-existing fault systems such as the Coastal Boundary and Akuapem fault zones. However, the absence of significant correlations at other lag periods indicates that precipitation alone does not control earthquake occurrence. These results advise that while tectonic processes remain the main driver of seismicity in southeastern Ghana, hydrological processes may act as secondary triggers influencing earthquake timing.

A densely populated place like a public university needs good internet and communication connectivity for effective academic work. As such, University campuses in Ghana are inundated with communication antennas. This study investigated how radiofrequency (RF) power density levels are affected by the elevations of different floors of high-rise buildings of a public university. A spectrum analyser coupled to a log-periodic antenna was used. The RF power density decreased from the ground floor to the third floor and only increased to maximum levels on the fourth floor. The variation across different floors indicates the influence of elevation on the measured EMF levels. The 900 MHz band produced the highest power density of 1.16E-03 W/m2 on the last (fourth) floor, suggesting that communication applications in the 900 MHz band are the most used by the university community.

Radiological safety assessment was carried out to assess the integrity and longevity of the barrier systems of the borehole disposal system (BDS) for the disposal of disused sources in Ghana. The design of the BDS incorporates both the engineered and natural barriers into its safety concept. The safety of the BDS requires confidence in the ability of the engineered barriers on the host environmental conditions to provide containment for the disused sources for a sufficient length of time. The results obtained from the scoping tool indicated that the dose limit was exceeded which showed that the containment provided by the engineered barriers was not sufficient to ensure safety of the disposal system for the specified environmental conditions and radionuclides inventory. Detailed modelling was performed with an AMBER model to evaluate the containment provided by the engineered barriers and the geosphere with some identified scenarios. The AMBER model results showed that the calculated peak dose from any of the disposed radionuclides for the identified scenarios was below the dose constraint of 0.3 mSv/y. The peak doses occurred around 2000-1000000 years. The peak doses were seen to be mainly derived from Ra-266 and Am-241 and/or their daughters. The disused sources could be disposed of safely in the disposal system either in an oxidizing or reducing fractured/porous flow environment without posing any significant radiological threat to humans and the environment.

For sustainable management of water resources, especially in geologically distinct environments, it is crucial to comprehend the geochemical evolution of groundwater. This study uses a novel combinatorial inverse geochemical modeling technique to identify the processes and mineralogical assemblages influencing the water quality of the Voltaian sedimentary and Birimian crystalline aquifers in Northern Ghana. The end-member compositions used to model water-rock interactions under thermodynamic equilibrium were the median ion concentrations obtained from spatially clustered groundwater water samples. To constrain the geochemical pathways, a suite of silicate, carbonate, and evaporite minerals was examined in thousands of mineral assemblage combinations. The results demonstrate that silicate weathering, particularly of albite, anorthite, K-feldspar, and phlogopite, dominates the evolution of major cations in both aquifers, with a stronger imprint in the Birimian terrain. In contrast, the Voltaian sedimentary aquifer is characterized by higher salinities, which can be attributed to human activity and possible deep saline water upwelling. It is also impacted by carbonate dissolution. Even though equilibrium models fairly predicted Birimian water chemistry, they were unable to fully replicate the ionic composition, particularly chloride, of the Voltaian groundwater. This suggests the influence of kinetic or slow-reacting processes. Supplementary simulations incorporating saline mixing, cation exchange, and CO2 equilibration further highlighted the dynamic complexity of the Voltaian aquifer system. This research demonstrates the utility of combinatorial inverse modeling in identifying mineral controls on groundwater chemistry and provides a methodological foundation for future reactive transport simulations in complex aquifer systems.

Radon concentrations and environmental factors were collected monthly over a period of one year in 10 different levels in an underground goldmine to determine the effect of environmental factors on radon concentration. The detectors were installed in batches within four quarters. The activity concentration within the year ranges from a minimum of 2 Bqm -3 to a maximum of 284Bqm -3 with a mean value of 58.51Bqm -3 . A positive relationship was observed between dry bulb temperature, relative humidity and radon concentration while a negative relationship was observed between barometric pressure, air quantity, wet bulb temperature and radon concentration and all the relationship was statistically insignificant but a principal component analysis deduced Barometric Pressure, Relative Humidity and Wet Bulb Temperature as the three main factors that influences the indoor radon concentration in the underground goldmine of which the wet bulb temperature was statistically significant at the 5% level of significance. Keywords: Radon, Environmental factors, Radon Concentration, Correlation, Principal Component Analysis DOI : 10.7176/APTA/88-02 Publication date : March 28th 2024

In this study, a comprehensive investigation was conducted to determine the radioactivity levels of naturally occurring radioactive materials (NORMs) in heap pads/soil and water samples within and around the operational area of Tarkwa Gold Mine in Ghana. Gamma-ray spectrometry was used to determine the activity concentrations of 238U, 232Th, and 40K in heap pads/soil, and 226Ra, 228Th, and 40K in water samples. The average activity concentrations of 226Ra and 228Th in all water samples were below the World Health Organisation (WHO) recommended guidelines for drinking water. Similarly, the average activity concentrations of measured radionuclides in heap pads/soil samples taken from depths of 0–20 cm and 20–50 cm were found to be below the worldwide average reported values. The annual effective dose to the public was estimated to be around 0.16 mSv, which is below the recommended limit. The values of the hazard indices are also below the recommended limits, implying that if heap pads/soils are used for building purposes and construction, they will not pose any significant radiation hazard. The results of this study indicate that radiation levels are within the natural background radiation levels reported in the literature and are consistent with findings from similar studies conducted in Ghana.

Soil and rock samples were collected monthly over a period of one year in 10 different levels in an underground goldmine to determine the radiological impact on workers. The samples were analysed using a high pure germanium detector. The average permissible value for the radionuclides were below the limits apart from Th-232. The lowest concentration of the natural radionuclides in soil and rock samples was observed in level 1000YOD and the highest concentration was observed in level 880. The hazard indices, exposure rate, excess lung cancer risk and annual effective dose from the rock and soil samples possess no radiological hazard if used for construction of buildings but the radium equivalent activity for level 880 were above the permissible limit and the mean excess life cancer risk (ELCR) for the naturally occurring radioactive materials in the soil and rock samples were above the average world value. Keywords : Radon Concentration, NORM, Underground goldmine, High Pure Germanium Detector. DOI: 10.7176/JEES/14-2-04 Publication date: March 31 st 2024

Indoor radon concentrations were collected monthly over a period of one year in 10 different levels in an underground goldmine to determine the radiological impact on workers. The detectors were installed in batches within four quarters. The measurements were carried out using LR115 solid state nuclear track detectors. The results show that the activity concentration of radon in the underground mine ranges from a minimum of 2 Bqm -3 to a maximum of 284 Bqm -3 with a mean value of 58.51 Bqm -3 . The highest radon concentration was observed in the second quarter when the season was warm, and the lowest radon concentration was observed in the first quarter when the season was colder. The hazard indices, exposure rate, excess lung cancer risk and annual effective dose from the rock and soil samples possess no radiological hazard if used for building materials. Keywords : Radon, Effective Dose, Radiological hazard, LR 115, Activity Concentration DOI: 10.7176/JEES/14-2-03 Publication date: March 31 st 2024

The calibration of radiological survey meters is an important consideration in achieving standardisation of doses. This provides traceability for field instruments to an International System of Units. Seventy-one digital survey meters were calibrated by the substitution method in a 137Cs beam in a secondary standard dosimetry laboratory using a PTW spherical ionisation chamber coupled to a Physikalisch-Technische-Werkstaetten (PTW) UNIDOS Electrometer. The calibration factors determined ranged from 0.59 to 1.98. Thirty-six pieces of equipment have their calibration factors within 0.9-1.1. A total of 36% of the survey meters recorded calibration factors corresponding to a percentage deviation above 20% whilst 64% fell within 20% deviations from the true value. The best value of a calibration factor obtained in this work was 1.00 from two survey meters. The errors due to survey meters being out of calibration can usually be corrected by frequent recalibration.

Indoor radon concentrations were collected monthly over a period of one year in 10 different levels in an underground goldmine and the data was analysed using a four moving average time series to determine the relationship between depths of the underground mine and the indoor radon concentration. The detectors were installed in batches within four quarters. The measurements were carried out using LR115 solid state nuclear track detectors. Statistical models are applied in the prediction and analysis of the radon concentration at various depths. The time series model predicted a positive relationship between the depth of the underground mine and the indoor radon concentration. Thus, elevated radon concentrations are expected at deeper levels of the underground mine, but the relationship was insignificant at the 5% level of significance with a negative adjusted R 2 (R 2 = – 0.021) due to an appropriate engineering and adequate ventilation rate in the underground mine. Keywords : LR115, Radon Concentration, Time Series, Underground goldmine, DOI: 10.7176/APTA/87-03 Publication date: April 30 th 2023

The level of knowledge and awareness of naturally occurring radioactive materials and indoor radon among underground goldmine workers were measured using a well-structured closed ended five-point likert scale questionnaire using a one sample T test for the analysis. There was a significant relationship between the awareness and knowledge of NORM and radon gas among the underground workers apart from the awareness and knowledge of the increased risk of cancer due to exposure of radon for workers who smoke. The level of awareness and knowledge is positively correlated with the level of education of respondents and negatively correlated to the years of service and age of respondents, but the ANOVA table indicates a statistical significance between the demographic data and the awareness and knowledge of radon gas and NORM in their working environment with an adjusted R 2 of 46.1%. Keywords : NORM, Indoor radon, correlation, awareness, knowledge. DOI: 10.7176/IKM/13-3-04 Publication date: April 30 th 2023

In response to mounting radiofrequency health concerns, this study was constituted to provide critical scientific data and assess any potential exposure from global system for mobile communication mobile phones. Specific absorption rate (SAR) from phones approved by the regulator and untested/unapproved phones were measured with a ComoSAR system. The maximum 10 g SAR (0.51 W/kg) and 1 g SAR (0.99 W/kg) measured were 25 and 62% of the International Commission on Non-Ionizing Radiation Protection and Federal Communication Commission limits, respectively. The approved phone produced statistically significant higher SAR values relative to the untested phone. SAR values of the right ear were relatively higher. All maximum SAR values were recorded on the right ear. The regulatory approval status of the phone, phone's orientation to the head, operating frequency channel and in which ear (right or left) the phone is used influenced the SAR measured. The SAR values of the approved phone compared favourably with similar studies while the unapproved phone does not.

The identification of the chemical status of groundwater is a prerequisite for the sustainable management and development of groundwater resources. A better assessment of the chemical status of the groundwater requires the knowledge and understanding of the natural background concentrations to establish threshold values of chemical pollutants in groundwater. The aim of this study is to estimate the natural background levels, the threshold value (TV) of nitratenitrogen (NO3--N) and to identify its source in the groundwater in the Bono, Ahafo and Bono East regions of Ghana. A total of 165 groundwater samples were taken from the crystalline and sedimentary aquifers in the study area. Iterative outlier removal technique and a Gaussian mixture model were then used to assess the natural background and threshold nitrate-nitrogen concentrations in the groundwater. Chloride data was then used to trace the NO3--N source in the groundwater. The estimated NBL of NO3--N in the area ranges from [0.001-3.9] mg/L with an expected value of 1.25 mg/L and calculated TV of 6.95 mg/L. The data suggest that NO3--N concentrations are homogeneous across all the lithologies underlying the study area. The results showed that agricultural, domestic, and denitrification contribute significantly to the loading of NO3--N concentration in the groundwater. The estimated threshold range of NO3--N provides the baseline nitrate-nitrogen concentration for future studies in the region. However, the results are inconclusive, and we recommend using isotopic detection (N-15-NO3- and O-18-NO3-) in future studies through comprehensive and sustainable regional monitoring of the aquifer system in order to further limit the source of nitrate-nitrogen in the groundwater system.

The development of in chip manufacturing processes has enhanced energy-efficient nano-electronic and highperformance devices in daily activities. In recent times, CMOS technology scaling has recognized several transistors in large-scale VLSI chips to support performance. However, these innovations have also frequently increased the impact of Soft-Error (SE) reliability concerns in computing architectures for Wireless Communications systems. Thus, this paper proposes an energy-efficient probability-based approximation method to significantly enhance SE mitigation using approximate logic circuits. Firstly, the dynamic-based probability performance indicates that the mandatory assignment (MA) function achieves an accurate detection result of P(E) - 0.130 better than the other functions. Then, to realize a quality SE detection and overcome SEs with multiple identities which leads to wrong SE detection at the vulnerable zones, the investigation sets a detection limit at 95% and 98%, respectively. However, it is observed that the higher the detection limit, the better measurement of precision for SE that occurred. Hence, the measurement of precision with 98% of detection limit outperforms significantly as compared with other detection limits. Further, an efficient algorithm is designed to maximize system performance. The results confirm the robustness of the proposed method and a more reliable performance as compared to other existing techniques.

The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region has undergone rapid population shift and urban sprawl. This has modified the natural environment of the area and led to the formation and warming of Urban Heat Island (UHI). Previous studies have not established enough evidence on the existence of UHI phenomenon in the region. For this reason, this study examined the existence, magnitude, and spatial extent of UHI warming as well as its effect on temperature extremes in the region. The study used Landsat satellite imagery captured in 1991, 2002 and 2017, and in-situ daily minimum and maximum temperature data spanning the period 1980 to 2017. The satellite images were processed and analyzed using an integrated Geographic Information System (GIS) and remote sensing technique while extreme temperature indices were assessed with the ClimPACT2 software. The study found that UHI existed in the region with an increasing spatial coverage and a magnitude of about 4.07 ∘C, 5.79 ∘C, and 4.86 ∘C in 1991, 2002, and 2017 respectively. The built-up and bare land areas experienced the strongest effect of UHI warming. In addition, enhanced UHI warming effect caused an increase in the frequency and intensity of warm temperature extremes in the region. A faster increase in night time temperatures than day time resulted in a decrease in diurnal temperature range of the region. Considering the high rate of warming amidst rapid urban expansion, more warming is expected in the region. This is expected to exacerbate climate extreme events and weather-related health issues. It is also expected to increase energy consumption, air pollution and human discomfort.

Internet of Things (IoT) network has been envisioned as a promising technology to satisfy the exponentially growing mobile traffic requirements. Cooperative communication technique has been proposed to significantly improve energy efficiency in resource-constrained network. In this paper, we focus on resource allocation optimization and optimal relay selection to maximize the energy efficiency of the IoT networks. Using different cooperative techniques, we have studied the resource optimization problems for a single-hop network topology and a generic cooperative multi-hop network topology. Based on dual optimization framework, we formulate an optimal algorithm to reduce the total transmit power through channel allocations and optimal relay selection for each source to destination communication link while satisfying the quality of service (QoS) requirements. We derive the closed-form expressions for the outage probabilities of the cooperative relaying protocols to improve data transmission and propose an energy efficient power routing algorithm to enhance energy efficiency. Simulation results show an effective performance gain of the proposed algorithm as compared with other existing power saving algorithms in terms of system throughput and energy efficiency.

In groundwater, dissolved organic matter (DOM), a complex material, is a contaminant of concern owing to its ability to influence water quality and stimulate microbial metabolism. Using a 445-nm diode laser-induced fluorescence (LIF) spectroscopy, DOM contamination levels have been investigated of well water samples fetched from ten privately owned hand-dug wells during dry and wet seasons of 2016, 2017 and 2018, in Ghana. The results showed spatio-temporal heterogeneities in the LIF spectra, and the fluorescence intensity peaks were generally higher and broader during the wet season than the dry season. In this study, DOM fluorescence spectra at an emission wavelength band of 460–650 nm showed two distinct broad peak shoulders within 480–500 nm and 550–570 nm, engulfing the water Raman peak at 527 ± 2 nm for all the water samples studied. Furthermore, principal component analysis and cluster analysis were used to differentiate the 2016 water samples based on their DOM contamination levels. In each case, three groups or clusters were identified based on their similarities and dissimilarities. The study revealed humic DOM substances as the most typical well water fluorophores. Applying the K-nearest neighbour algorithm as a classifier method for the classification of 30 water samples studied in 2016, 16.7% (5/30) were classified as very good drinking water, 46.7% (14/30) as good, 26.7% (8/30) as fairly good, and 10% (3/30) as bad drinking water samples. In general, levels of dissolved organic matter contamination increased over the study period during the rainy seasons for wells situated in close proximity to septic tanks, refuse dumps, public toilets and in wetlands. Thus, in the study the fluorescence intensity depends on the sampling site and the season, and indicates the DOM contamination level.

The mean annual potential recharge rate to the ground water system in the Tarkwa gold mining district of South Western Ghana, has been estimated for the period 1977 to 2001 by analyzing precipitation recharge in response to rainfall pattern and distribution for the four main soil types; Huni, Tarkwa Phyllite, Banket and Kawere. Using the Hydrus-1D infiltration computer code model, simulation results of recharge-precipitation exhibited a linear relationship, and gave correlation coefficient values R2 ranging from 0.39 to 0.55 for the four soil types and 0.72 for the composite soil. Variability of annual recharge was assigned to various reasons, including the variation in the weather pattern (rainfall, temperature, evapotranspiration etc), topography and hydraulic properties of the aquifer system. The potential direct recharge rate was estimated to range from 269 mm/yr to 611 mm/yr, with an average value of 385 mm/yr. This is as a result of infiltration of about 18% to 36% (average 27%) of the mean annual precipitation. The high average value of 385 mm/yr is reasonable on the basis that it represents the potential maximum value of the actual recharge value of 299±72 mm/yr.

Polymer products have been applied in all spheres of life and their disposal after use has been a problem. In Ghana, non-biodegradable polymer products in the form of used water-sachet bags is littered everywhere. Coconut husk, which is a natural fiber, is also available as waste. We explore a means of recycling sachet-water bags and coconut husk to yield a useful product. A composite was formed by melting the polyethylene, into which was dispersed coconut fiber, and then allowed to set. Varied masses of fiber were added after which water absorption test, hardness/compressive and flexure tests were conducted on the composite product. The absorption rate of the composite increased with increasing composition of fiber, meaning that the porosity of the material was influenced by the amount of fiber. Increasing the fiber content increased the load needed to compress the sample, indicating an increase in the strength of the composite. The load-bearing capacity increased by 120 % when 450.5 g of fiber was added to the control sample, and further increased to 800 % when the fiber mass was increased to 804.4 g. With an amount of 100 g of fiber added to the polyethylene, the flexure increased by about 5.73 % and by about 31.46 % when 450 g of fiber was added. There was therefore improvement in the mechanical properties of the composite formed, and consequently such waste products can be put to use in applications like the production of ceilings, partition boards, automobile interiors and the likes.