The UNSCEAR [1] observed that there could be some exposure at work which would require regulatory... more The UNSCEAR [1] observed that there could be some exposure at work which would require regulatory control but is not really considered. This study was, then, set up to evaluate the annual effective dose equivalent of 25 Laboratories in Town Campus of University of Uyo, Nigeria and to determine if the evaluated dose levels could lead to any radiological health effect in the workers, and also to determine if the laboratories require regulatory control. The radiation exposure at the laboratories measured using Inspector alert surveying meter were converted to effective dose and compared with the public and occupational values. From the results, the effective dose equivalent were moderately low varying from 0.128±0.041mSv/yr to 0.309±0.049mSv/yr with mean value of 0.2294±0.0465 except in pharmaceutical/Medicinal Chemistry Laboratory store room (SA 25) where higher value of 1.015±0.09mS/yr was recorded. The evaluated effective dose values in the laboratories were below public and occupat...
This research examined the observed datasets and a theoretically derived model for estimating yea... more This research examined the observed datasets and a theoretically derived model for estimating yearly optimum tilt angle (β), maximum incident solar radiation (Hmax), clean gain indicator (CGI), and soiling loss indicator (SLI) at Mumbwa, Zambia, the Mediterranean Region, and low latitude locations across the globe. The cleaned tilted collector emerged as the best performing collector due to Hmax and much higher energy gains compared with the soiled collector. CGI showed an appreciable performance of 0.4737% over -0.4708% on the SLI, indicating that soiling on the surface of photovoltaic (PV) modules significantly depreciates the overall performance of PV modules. Two established empirical models obtained from the literature were compared with the established theoretical model (β=φ). The result revealed that the two models overestimated the observed annual optimum tilt angle in this paper, simply because the models were developed with high latitude location datasets from the Asia con...
We evaluated and compared the performance of simulated Angström-Prescott (AP) and Hargreaves-Sama... more We evaluated and compared the performance of simulated Angström-Prescott (AP) and Hargreaves-Samani (HS) models on monthly and annual timescales using generalized datasets covering the entire West African region. The fitted AP model yielded more efficient parameters of a = 0.366 and b = 0.459, whereas the HS model produced a 0.216 coefficient based on an annual timescale, which is more suitable in the region compared to coefficients recommended by the Food and Agriculture Organization (FAO) (a = 0.25 and b = 0.5) and HS (0.17), respectively. Employing the FAO and HS recommended coefficients will introduce a relative percentage error (RPE) of 18.388% and 27.19% compared to the RPEs of 0.0014% and 0.1036% obtained in this study, respectively. When considering time and resource availability in the absence of ground-measured datasets, the coefficients obtained in this study can be used for predicting global solar radiation within the region. According to the AP and HS coefficients, the ...
The global agenda to increase the renewable energy share has driven many countries and entities t... more The global agenda to increase the renewable energy share has driven many countries and entities to harness solar energy from solar photovoltaic (PV) systems. However, the power generation of PV systems is strongly affected by climate conditions. Therefore, the main objective of this study is to analyze and predict the power generation of different PV technologies under arid desert climate conditions on an hourly basis. Two areas have been considered as case studies: Adrar in Algeria and Alice Springs in Australia. A total of nine physical models and input parameter combinations from six different power plants have been used and tested for the suitability of the proposed models for predicting the power yield of PV power plants depending on solar irradiance and other meteorological variables. Then, an ensemble learning technique is applied to improve the performance capabilities of the best-fit input combinations. The results reveal that the global irradiance, ambient air temperature,...
Potential evapotranspiration (PET) is a particularly important parameter for understanding water ... more Potential evapotranspiration (PET) is a particularly important parameter for understanding water interactions and balance in ecosystems, while it is also crucial for assessing vegetation water requirements. The accurate estimation of PET is typically data demanding, while specific climatic, geographical and local factors may further complicate this task. Especially in city environments, where built-up structures may highly influence the micrometeorological conditions and urban green sites may occupy limited spaces, the selection of proper PET estimation approaches is critical, considering also data availability issues. In this study, a wide variety of empirical PET methods were evaluated against the FAO56 Penman–Monteith benchmark method in the environment of two Mediterranean urban green sites in Greece, aiming to investigate their accuracy and suitability under specific local conditions. The methods under evaluation cover all the range of empirical PET estimations: namely, mass tr...
Given the interdependence of climate change (CLC) and urban expansion (URE) on ecosystem producti... more Given the interdependence of climate change (CLC) and urban expansion (URE) on ecosystem productivity in China and India, hybrid physics-based models were fitted in this study to evaluate the effects of these variables on photosynthetically active radiation (PAR). This was accomplished by interpolating the most recent five general circulation models (GCMs) from coupled model intercomparison project phase 6 (CMIP6) into the CMIP6 multi-ensemble model. The potential of PAR is projected to increase by 0.001 to 2.077% in China and by 0.002 to 6.737% in India, on a seasonal and annual basis, if the warming is kept at 1.5 °C from now until the end of this century. The effects of CLC and URE on the changes in PAR in China and India were investigated, and URE had a greater impact than CLC when compared to effective contributions, with 49.47% for China and 28.41% for India in the entire case scenario. In contrast, CLC and PAR residual factor (PRF) have a greater impact in India than in China...
The present research was designed to examine the genetic analysis of egg weight, egg yolk weight ... more The present research was designed to examine the genetic analysis of egg weight, egg yolk weight and egg albumen weight of Bovan Neva Black laying hens at 25, 51 and 72 weeks. For this purpose, thirty birds were selected from the layer flock in the Babcock University Teaching and Research Farm. They were individually housed in separate labeled battery cage. A total of thirty eggs were collected daily from the birds continuously in five days of egg production, at each age of 25, 51 and 72 weeks. The total number of eggs collected at each age were 150. Data collected for egg weight, egg yolk weight and egg albumen weight were used to evaluate the descriptive statistics, influence of age and Pearson correlation coefficient on different age groups. The mean values of the traits revealed a consistent increase in egg weight 55.02-63.29 g, egg yolk weight 13.14-19.39 g and egg albumen weight 35.52-39.21 g by aging. A significant positive genetic correlation was obtained among traits with l...
In-situ measurements of the equivalent dose in 1 Svhr at twenty two locations within Ikot Akp... more In-situ measurements of the equivalent dose in 1 Svhr at twenty two locations within Ikot Akpaden Campus of Akwa Ibom State University, Nigeria, using Portable Inspector Alert Nuclear Radiation Monitor, have been conducted. Hundred measurements per study location were taken for averaging. The average values with standard error were for each location converted to annual dose rate in 1 mSvyr and presented. The result of the computed mean equivalent dose rate for the University Community was 1 0240 .
The UNSCEAR [1] observed that there could be some exposure at work which would require regulatory... more The UNSCEAR [1] observed that there could be some exposure at work which would require regulatory control but is not really considered. This study was, then, set up to evaluate the annual effective dose equivalent of 25 Laboratories in Town Campus of University of Uyo, Nigeria and to determine if the evaluated dose levels could lead to any radiological health effect in the workers, and also to determine if the laboratories require regulatory control. The radiation exposure at the laboratories measured using Inspector alert surveying meter were converted to effective dose and compared with the public and occupational values. From the results, the effective dose equivalent were moderately low varying from 0.128±0.041mSv/yr to 0.309±0.049mSv/yr with mean value of 0.2294±0.0465 except in pharmaceutical/Medicinal Chemistry Laboratory store room (SA 25) where higher value of 1.015±0.09mS/yr was recorded. The evaluated effective dose values in the laboratories were below public and occupat...
This research examined the observed datasets and a theoretically derived model for estimating yea... more This research examined the observed datasets and a theoretically derived model for estimating yearly optimum tilt angle (β), maximum incident solar radiation (Hmax), clean gain indicator (CGI), and soiling loss indicator (SLI) at Mumbwa, Zambia, the Mediterranean Region, and low latitude locations across the globe. The cleaned tilted collector emerged as the best performing collector due to Hmax and much higher energy gains compared with the soiled collector. CGI showed an appreciable performance of 0.4737% over -0.4708% on the SLI, indicating that soiling on the surface of photovoltaic (PV) modules significantly depreciates the overall performance of PV modules. Two established empirical models obtained from the literature were compared with the established theoretical model (β=φ). The result revealed that the two models overestimated the observed annual optimum tilt angle in this paper, simply because the models were developed with high latitude location datasets from the Asia con...
We evaluated and compared the performance of simulated Angström-Prescott (AP) and Hargreaves-Sama... more We evaluated and compared the performance of simulated Angström-Prescott (AP) and Hargreaves-Samani (HS) models on monthly and annual timescales using generalized datasets covering the entire West African region. The fitted AP model yielded more efficient parameters of a = 0.366 and b = 0.459, whereas the HS model produced a 0.216 coefficient based on an annual timescale, which is more suitable in the region compared to coefficients recommended by the Food and Agriculture Organization (FAO) (a = 0.25 and b = 0.5) and HS (0.17), respectively. Employing the FAO and HS recommended coefficients will introduce a relative percentage error (RPE) of 18.388% and 27.19% compared to the RPEs of 0.0014% and 0.1036% obtained in this study, respectively. When considering time and resource availability in the absence of ground-measured datasets, the coefficients obtained in this study can be used for predicting global solar radiation within the region. According to the AP and HS coefficients, the ...
The global agenda to increase the renewable energy share has driven many countries and entities t... more The global agenda to increase the renewable energy share has driven many countries and entities to harness solar energy from solar photovoltaic (PV) systems. However, the power generation of PV systems is strongly affected by climate conditions. Therefore, the main objective of this study is to analyze and predict the power generation of different PV technologies under arid desert climate conditions on an hourly basis. Two areas have been considered as case studies: Adrar in Algeria and Alice Springs in Australia. A total of nine physical models and input parameter combinations from six different power plants have been used and tested for the suitability of the proposed models for predicting the power yield of PV power plants depending on solar irradiance and other meteorological variables. Then, an ensemble learning technique is applied to improve the performance capabilities of the best-fit input combinations. The results reveal that the global irradiance, ambient air temperature,...
Potential evapotranspiration (PET) is a particularly important parameter for understanding water ... more Potential evapotranspiration (PET) is a particularly important parameter for understanding water interactions and balance in ecosystems, while it is also crucial for assessing vegetation water requirements. The accurate estimation of PET is typically data demanding, while specific climatic, geographical and local factors may further complicate this task. Especially in city environments, where built-up structures may highly influence the micrometeorological conditions and urban green sites may occupy limited spaces, the selection of proper PET estimation approaches is critical, considering also data availability issues. In this study, a wide variety of empirical PET methods were evaluated against the FAO56 Penman–Monteith benchmark method in the environment of two Mediterranean urban green sites in Greece, aiming to investigate their accuracy and suitability under specific local conditions. The methods under evaluation cover all the range of empirical PET estimations: namely, mass tr...
Given the interdependence of climate change (CLC) and urban expansion (URE) on ecosystem producti... more Given the interdependence of climate change (CLC) and urban expansion (URE) on ecosystem productivity in China and India, hybrid physics-based models were fitted in this study to evaluate the effects of these variables on photosynthetically active radiation (PAR). This was accomplished by interpolating the most recent five general circulation models (GCMs) from coupled model intercomparison project phase 6 (CMIP6) into the CMIP6 multi-ensemble model. The potential of PAR is projected to increase by 0.001 to 2.077% in China and by 0.002 to 6.737% in India, on a seasonal and annual basis, if the warming is kept at 1.5 °C from now until the end of this century. The effects of CLC and URE on the changes in PAR in China and India were investigated, and URE had a greater impact than CLC when compared to effective contributions, with 49.47% for China and 28.41% for India in the entire case scenario. In contrast, CLC and PAR residual factor (PRF) have a greater impact in India than in China...
The present research was designed to examine the genetic analysis of egg weight, egg yolk weight ... more The present research was designed to examine the genetic analysis of egg weight, egg yolk weight and egg albumen weight of Bovan Neva Black laying hens at 25, 51 and 72 weeks. For this purpose, thirty birds were selected from the layer flock in the Babcock University Teaching and Research Farm. They were individually housed in separate labeled battery cage. A total of thirty eggs were collected daily from the birds continuously in five days of egg production, at each age of 25, 51 and 72 weeks. The total number of eggs collected at each age were 150. Data collected for egg weight, egg yolk weight and egg albumen weight were used to evaluate the descriptive statistics, influence of age and Pearson correlation coefficient on different age groups. The mean values of the traits revealed a consistent increase in egg weight 55.02-63.29 g, egg yolk weight 13.14-19.39 g and egg albumen weight 35.52-39.21 g by aging. A significant positive genetic correlation was obtained among traits with l...
In-situ measurements of the equivalent dose in 1 Svhr at twenty two locations within Ikot Akp... more In-situ measurements of the equivalent dose in 1 Svhr at twenty two locations within Ikot Akpaden Campus of Akwa Ibom State University, Nigeria, using Portable Inspector Alert Nuclear Radiation Monitor, have been conducted. Hundred measurements per study location were taken for averaging. The average values with standard error were for each location converted to annual dose rate in 1 mSvyr and presented. The result of the computed mean equivalent dose rate for the University Community was 1 0240 .
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Papers by Samuel Nwokolo