chukwuma emmanuel | UPM - Universiti Putra Malaysia (original) (raw)

Papers by chukwuma emmanuel

Biomass Conversion and Biorefinery

Access to affordable clean energy sources as stipulated in United Nations Sustainable Development... more Access to affordable clean energy sources as stipulated in United Nations Sustainable Development Goal (UN SDG) number 7 is important for the development and socioeconomic well-being of people; the need for proper assessment of resources to achieve this goal is indisputable. The goal of this study is to assess the economic feasibility of utilizing an organic fraction of municipal solid wastes (MSW of) using a case study of local government areas (LGA) or Authority for Anambra State of Nigeria for waste to energy project. Smooth adoption of waste to energy projects requires investigation on the economic feasibility parameters necessary for such a project. This study therefore investigated the quantity of organic fraction of MSW, energy recovery and an optimum number of plants considering the economy of scales at the various LGAs of the study area. The result of the study indicates that about 198 tons maximum value of MSW of can be generated daily in Aguata LGA, with an electric energy potential value of 545 MW. The number of plants for the LGAs ranged from 10 to 50 and from 3 to 12 for small-and medium-scale plants. A large-scale plant of about 50 m 3 can possibly be installed at all the LGAs, with a maximum of 4 plants in Idemili and Aguata LGA. The economic assessment based on net present value (NPV) criteria shows poor economic feasibility for a small-scale plant, while NPV was positive for medium-and large-scale plants. The internal rate of return (IRR) ranged from 0.32 to 0.94, with a general increase from small-scale to large-scale economic feasibility. This study can be replicated in other regions; it is suggested that the autonomy of the various LGAs in the country should serve as a major motivation in adopting bio-energy projects independently, and this study will serve as a decision toolkit in the appropriate scale to be adopted.

ZANCO JOURNAL OF PURE AND APPLIED SCIENCES, 2018

Renewable Energy, 2021

Environmental concerns have increased over environmental hazards associated with fossil energy so... more Environmental concerns have increased over environmental hazards associated with fossil energy source, transition to renewable energy sources have been emphasized, this however requires relevant data for informed decision making. Critical analytical methods in situating bioenergy plants for bioenergy production are advantageous from environmental, economic and sustainable perspectives. A study therefore was undertaken to provide relevant data on biogas renewable energy source using Anambra State of Nigeria as a case study. The study was carried out using the power of Geographical Information System (GIS) technology. Several GIS thematic layers were obtained considering important factors in bioenergy plant location analysis. GIS-based thematic maps used for the production of the suitability map include political boundary map layer, road network layer, Land Use and Land Cover (LULC) layer, Digital Elevation Map (DEM) layer, river layer, slope layer, electric transmission line network layer, biomass potential density layer etc. Considering the fact that bioenergy plant is dependent on heat energy source which is also abundant in the tropics, hill-shade layer was integrated into the GIS location suitability analysis. Various economic and socio-environmental factors were considered and utilized in the development of economic, land suitability and bio-resource spatial density maps. These thematic maps were overlaid to obtain the final suitability map index. The most suitable sites identified were located in Njikoka, Onitsha North and Dunukofia Local Government Areas (L.G.As) of the Study area. The annual cumulative bio-wastes generated from the three LGA are 9,133,220 kg, 3,992,735 kg, and 6,909,450 kg respectively. It is recommended that government and stake-holders should take this study as a veritable tool in green energy technology implementation plan.

Environmental Challenges

Recently, natural fibers have gained research attention in reinforcing polymers due to their avai... more Recently, natural fibers have gained research attention in reinforcing polymers due to their availability and unique properties in polymer applications. Preliminary studies indicate indiscriminate disposal of human hair (HH) and the burning of cow hair (CH) and sheep hair (SH) by abattoir operators in Nigeria; this has become a source of concern owing to the hazardous nature of these activities to human health and the environment. This study is, therefore, essential and seeks to utilize these waste materials in an environmentally sustainable way, as the hair fibers used in this work are renewable and will enhance the economy of any country if adequately utilized. The composites of Polypropylene (PP), human, sheep, and cow tail hair fibers were prepared at different weight percentage concentrations of 0, 2, 4, 6, and 8 w% using an injection molding machine. Untreated and treated PP composites were analyzed for average diameter, length, and density; the composites were also characterized for ultimate tensile strength, flexural strength, hardness, and impact strength. The average diameter assessment indicates viz: Cow tail hair > Human hair > Sheep hair. The sequence for hair fiber lengths shows that Sheep hair > Human hair > Cow hair, and the order for average density is Cow tail hair > Human hair > Sheep hair. The analysis of the mechanical properties of the reinforced and unreinforced PP composite showed that the Human hair/PP composite gave the best enhancement for ultimate tensile strength and modulus, flexural strength, and modulus at 8% fiber loading. Cow tail hair/PP composite yielded the best elongation at break at 2% fiber loading. Human hair/PP composite showed the best yield for impact strength at 4% fiber loading, while the Cow tail hair composite performed best for the hardness test at 2% fiber loading. The surface scanning electronic microscope (SEM) images showed no significant manufacturing defect on composites except for the air entrapment in the image of cow tail hair. The study also observed that there is no fiber breakage or void observed in the images. SEM images of the PP-composites interface at 8% maximum loading showed reasonably good fiber adhesion to the polymer matrix. This study is recommended for environmental sustainability and to improve material properties for various applications.

Elsevier Journal of Renewable Energy, 2021

Environmental concerns have increased over environmental hazards associated with fossil energy so... more Environmental concerns have increased over environmental hazards associated with fossil energy source, transition to renewable energy sources have been emphasized, this however requires relevant data for informed decision making. Critical analytical methods in situating bioenergy plants for bioenergy production are advantageous from environmental, economic and sustainable perspectives. A study therefore was undertaken to provide relevant data on biogas renewable energy source using Anambra State of Nigeria as a case study. The study was carried out using the power of Geographical Information System (GIS) technology. Several GIS thematic layers were obtained considering important factors in bioenergy plant location analysis. GIS-based thematic maps used for the production of the suitability map include political boundary map layer, road network layer, Land Use and Land Cover (LULC) layer, Digital Elevation Map (DEM) layer, river layer, slope layer, electric transmission line network layer, biomass potential density layer etc. Considering the fact that bioenergy plant is dependent on heat energy source which is also abundant in the tropics, hill-shade layer was integrated into the GIS location suitability analysis. Various economic and socio-environmental factors were considered and utilized in the development of economic, land suitability and bio-resource spatial density maps. These thematic maps were overlaid to obtain the final suitability map index. The most suitable sites identified were located in Njikoka, Onitsha North and Dunukofia Local Government Areas (L.G.As) of the Study area. The annual cumulative bio-wastes generated from the three LGA are 9,133,220 kg, 3,992,735 kg, and 6,909,450 kg respectively. It is recommended that government and stake-holders should take this study as a veritable tool in green energy technology implementation plan.

Springer, Biomass Conversion and Biorefinery, 2021

Access to affordable clean energy sources as stipulated in United Nations Sustainable Development... more Access to affordable clean energy sources as stipulated in United Nations Sustainable Development Goal (UN SDG) number 7 is important for the development and socioeconomic well-being of people; the need for proper assessment of resources to achieve this goal is indisputable. The goal of this study is to assess the economic feasibility of utilizing an organic fraction of municipal solid wastes (MSW of) using a case study of local government areas (LGA) or Authority for Anambra State of Nigeria for waste to energy project. Smooth adoption of waste to energy projects requires investigation on the economic feasibility parameters necessary for such a project. This study therefore investigated the quantity of organic fraction of MSW, energy recovery and an optimum number of plants considering the economy of scales at the various LGAs of the study area. The result of the study indicates that about 198 tons maximum value of MSW of can be generated daily in Aguata LGA, with an electric energy potential value of 545 MW. The number of plants for the LGAs ranged from 10 to 50 and from 3 to 12 for small-and medium-scale plants. A large-scale plant of about 50 m 3 can possibly be installed at all the LGAs, with a maximum of 4 plants in Idemili and Aguata LGA. The economic assessment based on net present value (NPV) criteria shows poor economic feasibility for a small-scale plant, while NPV was positive for medium-and large-scale plants. The internal rate of return (IRR) ranged from 0.32 to 0.94, with a general increase from small-scale to large-scale economic feasibility. This study can be replicated in other regions; it is suggested that the autonomy of the various LGAs in the country should serve as a major motivation in adopting bio-energy projects independently, and this study will serve as a decision toolkit in the appropriate scale to be adopted.

Elsevier Environmental Challenges, 2023

Recently, natural fibers have gained research attention in reinforcing polymers due to their avai... more Recently, natural fibers have gained research attention in reinforcing polymers due to their availability and unique properties in polymer applications. Preliminary studies indicate indiscriminate disposal of human hair (HH) and the burning of cow hair (CH) and sheep hair (SH) by abattoir operators in Nigeria; this has become a source of concern owing to the hazardous nature of these activities to human health and the environment. This study is, therefore, essential and seeks to utilize these waste materials in an environmentally sustainable way, as the hair fibers used in this work are renewable and will enhance the economy of any country if adequately utilized. The composites of Polypropylene (PP), human, sheep, and cow tail hair fibers were prepared at different weight percentage concentrations of 0, 2, 4, 6, and 8 w% using an injection molding machine. Untreated and treated PP composites were analyzed for average diameter, length, and density; the composites were also characterized for ultimate tensile strength, flexural strength, hardness, and impact strength. The average diameter assessment indicates viz: Cow tail hair > Human hair > Sheep hair. The sequence for hair fiber lengths shows that Sheep hair > Human hair > Cow hair, and the order for average density is Cow tail hair > Human hair > Sheep hair. The analysis of the mechanical properties of the reinforced and unreinforced PP composite showed that the Human hair/PP composite gave the best enhancement for ultimate tensile strength and modulus, flexural strength, and modulus at 8% fiber loading. Cow tail hair/PP composite yielded the best elongation at break at 2% fiber loading. Human hair/PP composite showed the best yield for impact strength at 4% fiber loading, while the Cow tail hair composite performed best for the hardness test at 2% fiber loading. The surface scanning electronic microscope (SEM) images showed no significant manufacturing defect on composites except for the air entrapment in the image of cow tail hair. The study also observed that there is no fiber breakage or void observed in the images. SEM images of the PP-composites interface at 8% maximum loading showed reasonably good fiber adhesion to the polymer matrix. This study is recommended for environmental sustainability and to improve material properties for various applications.

Springer Environmental Science and Pollution Research, 2023

This study evaluated the susceptibility to groundwater pollution using a modified DRASTIC model. ... more This study evaluated the susceptibility to groundwater pollution using a modified DRASTIC model. A novel hybrid multicriteria decision-making (MCDM) model integrating Interval Rough Numbers (IRN), Decision Making Trial and Evaluation Laboratory (DEMATEL), and Analytical Network Process (ANP) was used to investigate the interrelationships between critical hydrogeologic factors (and determine their relative weights) via a novel vulnerability index based on the DRASTIC model. The flexibility of GIS in handling spatial data was employed to delineate thematic map layers of the hydrogeologic factors and to improve the DRASTIC model. The hybrid MCDM model results show that net recharge (a key hydrogeologic factor) had the highest priority with a weight of 0.1986. In contrast, the topography factor had the least priority, with a weight of 0.0497. A case study validated the hybrid model using Anambra State, Nigeria. The resultant vulnerability map shows that 12.98% of the study area falls into a very high vulnerability class, 31.90% falls into a high vulnerability, 23.52% falls into the average vulnerability, 21.75% falls into a low vulnerability, and 9.85% falls into very low vulnerability classes, respectively. In addition, nitrate concentration was used to evaluate the degree of groundwater pollution. Based on observed nitrate concentration, the modified DRASTIC model was validated and compared to the traditional DRASTIC model; interestingly, the spatial model of the modified DRASTIC model performed better. This study is thus critical for environmental monitoring and implementing appropriate management interventions to protect groundwater resources against indiscriminate sources of pollution.

Elseiver Environmental Challenges, 2023

The amount of waste generated in the modern world is constantly on the increase due to world's ur... more The amount of waste generated in the modern world is constantly on the increase due to world's urbanization, industrialization and population increase, thus there is a need to recycle these wastes especially non-biodegradable types. The aim and objective of this research was to produce bio-oil, bio-char, and bio-gas from waste tire using a fixed batch pyrolysis reactor, determine yield at three different temperatures of 400, 550 and 750 °C, determine the calorific value, flash and fire points, cloud and pour points, ash content, moisture content as well as concentration of Zn, Cd, Fe, Cr, Cu, and Pb in the produced bio-oil as well as in the original tire sample. The result shows that the char, oil and gas yields at the three different temperatures analysed for were 62, 24, 14; 48, 36.2, 15.8; and 42, 40, 18 respectively all in weight percent. The char and oil yield was determined by weight measurement, while that of gas was determine by mass balancing. The caloric value of the oil produced was found to be 64.44 KJ/kg, the flash and fire points were found to be 67 and 85 °C while the cloud and pour points were found to be 16 and-3 °C. The ash content and moisture content were found to be 0.04 and 8.18 in weight percent. The heavy metal concentration of the original tire sample was found to be 0.605 Cu, 0.170 Pb, 1.019 Zn, 0.777 Cr, 0.077 Cd and 0.447 Fe while the bio-oil produced contains 0.065 Cu, 0.090 Pb, 0.144 Zn, 2.121Cr, 0.006 Cd and 0.010 Fe all in ppm. This result shows that the rector used has a maximum oil yield of 40% w at 750 °C, and that the oil produced showed decrease in heavy metal concentration when compared to that present in the original tire sample and other petroleum products. Further studies should be conducted to extrapolate the reactor since it produced oil with high thermal stability and caloric value with low ash content and also decreased the heavy metal composition of the oil produced. The heavy metal concentration of other toxic metal should be analysed to further examine its public health risk.

Current Research in Green and Sustainable Chemistry

There is increased enthusiasm towards the use of natural hair fibers for plastic reinforcement du... more There is increased enthusiasm towards the use of natural hair fibers for plastic reinforcement due to their toughness and light weight. In this research, low density polyethylene (LDPE) was reinforced using 0.25 M NaOH treated cow tail, human and sheep hair fibers at 2, 4, 6 and 8% concentration respectively prior to injection moulding. The average densities, diameters and lengths of hair fibres were assessed The results obtained from the analysis of reinforced LDPE composites indicated that cow tail hair gave the highest average density and diameter. Sheep hair had the highest length after grinding. The study also analyzed the ultimate tensile strength and modulus, flexural strength and modulus, elongation, impact and hardness test on the polymer and their composites as well as the morphology and statistical analysis of the composite. This study indicated that human hair LDPE composites achieved highest flexural strength, flexural modulus, ultimate tensile strength and tensile modulus at 8% fibre loading whereas elongation at break and hardness were at 4% fibre loading while impact strength was at 2%. The cow tail hair LDPE composite gave the best impact strength at 8% fibre loading and sheep hair at 6%. The SEM results showed no serious manufacturing defects on the composites. The analysis of variance indicated that only the means of the composites' flexural properties were statistically significant. This study shows that short animal hair fibres could be effectively used to reinforced LDPE, and therefore suggest an alternative waste management strategy of these natural fibres that are currently viewed as environmental nuisance in the study area.

Scientific African

This work explores the use of chito-protein synthesized from fish scale as a bio-coagulant in Aba... more This work explores the use of chito-protein synthesized from fish scale as a bio-coagulant in Abattoir wastewater (AW) treatment. The effect of settling time, pH, adsorbent dosage, and temperature of coagulation on Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), turbidity, and Color from the AW sample were studied. The kinetic study was carried out using four process equilibrium models which are Langmuir, Freundlich, Frumkin, and Tempkin to investigate the mechanism of the reaction. SEM and FTIR spectral analyses were used to evaluate the surface morphology and chemical composition of the bio-coagulant. A low pH, 3 g of dosage in 250 mL vessel, settling period of 30 to 35 min, and temperatures of 323 K for all parameters resulted in the most efficient pollutant elimination. Turbidity, however, had an optimal temperature of 313 K. The result of the study shows that Langmuir model provided the best fit from the equilibrium models compared to Freundlich, Frumkin, and Temkin's models. The experimental data suited the Elovich, Pseudo-first, and Second order kinetic models' analysis and the high values of the regression coefficient of 0.90 supported the idea of perikinetic as the governing mechanism of coag-flocculation in the study. It can be inferred from this study that fish scale as a biocoagulant provides a significant resource for abattoir wastewater treatment.

International Journal of Thermofluids

The dynamics of solid objects falling through a viscous fluid was studied. The forces that contro... more The dynamics of solid objects falling through a viscous fluid was studied. The forces that control the motion as well as the effects of fluid viscosity and object density were studied using an analytical model. Wall effect due to the presence of finite fluid boundaries was evaluated using CFD. Through further correlation of the CFD results, a functional approximation model required to predict the limiting condition for wall effect was developed. The analytical solution gave a good approximation of the forces that control the motion and some indications that the effect of fluid viscosity is paramount in resisting the motion of the solid particle in a viscous fluid. The CFD approach was able to evaluate the system more accurately and allowed for the effects of finite fluid boundaries on the object motion to be calculated successfully. The analytical results agree largely with that of the CFD obtained in the range of vessel internal diameter D ≥ 2m which corresponds to the region where wall-effect is insignificant. The theoretical models were validated using experimental data.

Innovative Food Science & Emerging Technologies

The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help ... more The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help improve the peeling performance of beetroot. MW-assisted IR peeling (MWIR) and IR peeling of beetroot were investigated and compared with the conventional hot-lye peeling method. Also, the effects of these peeling methods on the quality and microstructure were evaluated. Hot-lye peeling at 95 • C for 40 s and 60 s was used as control. Results showed that MW-assisted IR peeling at power 640 W and heating time 7 min produced samples with the highest peelability (99.4%), lowest peel thickness (0.075 mm), and peel remaining (0.8%), lower peeling loss (4.23 g), and better peeling easiness when compared with lye peeling and IR peeling. IR peeling alone produced samples with the lowest peeling loss (2.87 g) and surface colour change, and the highest vitamin C retention (75.32%) than MW-assisted IR and lye peeling respectively. The product microstructure for the different peeling methods showed cellular distortion as a result of thermal expansion. MW pretreatment shows a promising potential to further develop the IR dry-peeling method, to replace the conventional hot lye chemical peeling.

Modeling Earth Systems and Environment

Erosion hazard is a major environmental change in developing countries and therefore necessitates... more Erosion hazard is a major environmental change in developing countries and therefore necessitates investigations for effective erosion control measures. This study is hinged on the numerous advantages of a hybrid Multi-Criteria Decision Model (MCDM) to assess erosion vulnerability using remote-sensed data and the application of Geographical Information System (GIS). Nine risk factors of erosion were selected for this study and their thematic maps were utilized to produce a spatial distribution of erosion hazard in the state. An integrated IVFRN-DEMATEL-ANP model was used to investigate the interrelationships between the risk factors and also obtain their final weights. The assessment model identified Rainfall, Erosivity Index, Stream Power Index, Sediment Transport Index, Topographic Wetness Index, and Soil as the most influential factors of erosion in the study area. The weighted linear combination method was used to integrate the risk factors to produce the spatial distribution of erosion vulnerability model. The method was validated using Anambra State of Nigeria. The findings from the study revealed that Anambra State is vulnerable to erosion hazard with 45% of the state lying between Very High and Medium vulnerable zones. A good predictive model performance of 89.7% was obtained using the AUC-ROC method. The feasibility of integrating the IVFRN, DEMATEL, and ANP models as an assessment model for mapping erosion vulnerability has been determined in this study, and this is vital in managing the impact of erosion hazards globally. The model's identification of hydrological and topographical factors as major causes of erosion hazard emphasizes the importance of critical analysis of risk factors as done in this study for effective management of erosion. This study is a veritable tool for implementation of erosion mitigation measures.

Modeling Earth Systems and Environment

Erosion hazard is a major environmental change in developing countries and therefore necessitates... more Erosion hazard is a major environmental change in developing countries and therefore necessitates investigations for effective erosion control measures. This study is hinged on the numerous advantages of a hybrid Multi-Criteria Decision Model (MCDM) to assess erosion vulnerability using remote-sensed data and the application of Geographical Information System (GIS). Nine risk factors of erosion were selected for this study and their thematic maps were utilized to produce a spatial distribution of erosion hazard in the state. An integrated IVFRN-DEMATEL-ANP model was used to investigate the interrelationships between the risk factors and also obtain their final weights. The assessment model identified Rainfall, Erosivity Index, Stream Power Index, Sediment Transport Index, Topographic Wetness Index, and Soil as the most influential factors of erosion in the study area. The weighted linear combination method was used to integrate the risk factors to produce the spatial distribution of erosion vulnerability model. The method was validated using Anambra State of Nigeria. The findings from the study revealed that Anambra State is vulnerable to erosion hazard with 45% of the state lying between Very High and Medium vulnerable zones. A good predictive model performance of 89.7% was obtained using the AUC-ROC method. The feasibility of integrating the IVFRN, DEMATEL, and ANP models as an assessment model for mapping erosion vulnerability has been determined in this study, and this is vital in managing the impact of erosion hazards globally. The model's identification of hydrological and topographical factors as major causes of erosion hazard emphasizes the importance of critical analysis of risk factors as done in this study for effective management of erosion. This study is a veritable tool for implementation of erosion mitigation measures.

Agricultural Engineering International: The CIGR Journal, 2019

Anambra state is faced with high population explosion and consequently high production of abattoi... more Anambra state is faced with high population explosion and consequently high production of abattoir wastes in major abattoir centres in the state. There is need for strategic waste management in allocation of bio-energy plants to digest these wastes. ArGIS software was used to perform hotspot Analysis to delineate clusters of abattoir potential features with values significantly higher or lower than the overall study area mean or average value. In addition, the set covering location model was used to determine the number of bio-energy treatment plant facilities that should be constructed in the study area and where they should be located. The result of the study indicated that eight abattoirs were classified as hotspot zones/locations (L), and consequently used in the set covering location modelling. The set covering location model indicates that a minimum of two bio-energy plant should be constructed in Obosi (L1) and Umunya (L8) of the study area. The outcome of the study would be...

Innovative Food Science and Emerging Technologies, 2022

The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help ... more The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help improve the peeling performance of beetroot. MW-assisted IR peeling (MWIR) and IR peeling of beetroot were investigated and compared with the conventional hot-lye peeling method. Also, the effects of these peeling methods on the quality and microstructure were evaluated. Hot-lye peeling at 95 • C for 40 s and 60 s was used as control. Results showed that MW-assisted IR peeling at power 640 W and heating time 7 min produced samples with the highest peelability (99.4%), lowest peel thickness (0.075 mm), and peel remaining (0.8%), lower peeling loss (4.23 g), and better peeling easiness when compared with lye peeling and IR peeling. IR peeling alone produced samples with the lowest peeling loss (2.87 g) and surface colour change, and the highest vitamin C retention (75.32%) than MW-assisted IR and lye peeling respectively. The product microstructure for the different peeling methods showed cellular distortion as a result of thermal expansion. MW pretreatment shows a promising potential to further develop the IR dry-peeling method, to replace the conventional hot lye chemical peeling.

International Journal of Thermofluids, 2022

The dynamics of solid objects falling through a viscous fluid was studied. The forces that contro... more The dynamics of solid objects falling through a viscous fluid was studied. The forces that control the motion as well as the effects of fluid viscosity and object density were studied using an analytical model. Wall effect due to the presence of finite fluid boundaries was evaluated using CFD. Through further correlation of the CFD results, a functional approximation model required to predict the limiting condition for wall effect was developed. The analytical solution gave a good approximation of the forces that control the motion and some indications that the effect of fluid viscosity is paramount in resisting the motion of the solid particle in a viscous fluid. The CFD approach was able to evaluate the system more accurately and allowed for the effects of finite fluid boundaries on the object motion to be calculated successfully. The analytical results agree largely with that of the CFD obtained in the range of vessel internal diameter D ≥ 2m which corresponds to the region where wall-effect is insignificant. The theoretical models were validated using experimental data.

Modeling Earth Systems and Environment, 2022

Erosion hazard is a major environmental change in developing countries and therefore necessitates... more Erosion hazard is a major environmental change in developing countries and therefore necessitates investigations for effective erosion control measures. This study is hinged on the numerous advantages of a hybrid Multi-Criteria Decision Model (MCDM) to assess erosion vulnerability using remote-sensed data and the application of Geographical Information System (GIS). Nine risk factors of erosion were selected for this study and their thematic maps were utilized to produce a spatial distribution of erosion hazard in the state. An integrated IVFRN-DEMATEL-ANP model was used to investigate the interrelationships between the risk factors and also obtain their final weights. The assessment model identified Rainfall, Erosivity Index, Stream Power Index, Sediment Transport Index, Topographic Wetness Index, and Soil as the most influential factors of erosion in the study area. The weighted linear combination method was used to integrate the risk factors to produce the spatial distribution of erosion vulnerability model. The method was validated using Anambra State of Nigeria. The findings from the study revealed that Anambra State is vulnerable to erosion hazard with 45% of the state lying between Very High and Medium vulnerable zones. A good predictive model performance of 89.7% was obtained using the AUC-ROC method. The feasibility of integrating the IVFRN, DEMATEL, and ANP models as an assessment model for mapping erosion vulnerability has been determined in this study, and this is vital in managing the impact of erosion hazards globally. The model's identification of hydrological and topographical factors as major causes of erosion hazard emphasizes the importance of critical analysis of risk factors as done in this study for effective management of erosion. This study is a veritable tool for implementation of erosion mitigation measures.

Biomass Conversion and Biorefinery

Access to affordable clean energy sources as stipulated in United Nations Sustainable Development... more Access to affordable clean energy sources as stipulated in United Nations Sustainable Development Goal (UN SDG) number 7 is important for the development and socioeconomic well-being of people; the need for proper assessment of resources to achieve this goal is indisputable. The goal of this study is to assess the economic feasibility of utilizing an organic fraction of municipal solid wastes (MSW of) using a case study of local government areas (LGA) or Authority for Anambra State of Nigeria for waste to energy project. Smooth adoption of waste to energy projects requires investigation on the economic feasibility parameters necessary for such a project. This study therefore investigated the quantity of organic fraction of MSW, energy recovery and an optimum number of plants considering the economy of scales at the various LGAs of the study area. The result of the study indicates that about 198 tons maximum value of MSW of can be generated daily in Aguata LGA, with an electric energy potential value of 545 MW. The number of plants for the LGAs ranged from 10 to 50 and from 3 to 12 for small-and medium-scale plants. A large-scale plant of about 50 m 3 can possibly be installed at all the LGAs, with a maximum of 4 plants in Idemili and Aguata LGA. The economic assessment based on net present value (NPV) criteria shows poor economic feasibility for a small-scale plant, while NPV was positive for medium-and large-scale plants. The internal rate of return (IRR) ranged from 0.32 to 0.94, with a general increase from small-scale to large-scale economic feasibility. This study can be replicated in other regions; it is suggested that the autonomy of the various LGAs in the country should serve as a major motivation in adopting bio-energy projects independently, and this study will serve as a decision toolkit in the appropriate scale to be adopted.

ZANCO JOURNAL OF PURE AND APPLIED SCIENCES, 2018

Renewable Energy, 2021

Environmental concerns have increased over environmental hazards associated with fossil energy so... more Environmental concerns have increased over environmental hazards associated with fossil energy source, transition to renewable energy sources have been emphasized, this however requires relevant data for informed decision making. Critical analytical methods in situating bioenergy plants for bioenergy production are advantageous from environmental, economic and sustainable perspectives. A study therefore was undertaken to provide relevant data on biogas renewable energy source using Anambra State of Nigeria as a case study. The study was carried out using the power of Geographical Information System (GIS) technology. Several GIS thematic layers were obtained considering important factors in bioenergy plant location analysis. GIS-based thematic maps used for the production of the suitability map include political boundary map layer, road network layer, Land Use and Land Cover (LULC) layer, Digital Elevation Map (DEM) layer, river layer, slope layer, electric transmission line network layer, biomass potential density layer etc. Considering the fact that bioenergy plant is dependent on heat energy source which is also abundant in the tropics, hill-shade layer was integrated into the GIS location suitability analysis. Various economic and socio-environmental factors were considered and utilized in the development of economic, land suitability and bio-resource spatial density maps. These thematic maps were overlaid to obtain the final suitability map index. The most suitable sites identified were located in Njikoka, Onitsha North and Dunukofia Local Government Areas (L.G.As) of the Study area. The annual cumulative bio-wastes generated from the three LGA are 9,133,220 kg, 3,992,735 kg, and 6,909,450 kg respectively. It is recommended that government and stake-holders should take this study as a veritable tool in green energy technology implementation plan.

Environmental Challenges

Recently, natural fibers have gained research attention in reinforcing polymers due to their avai... more Recently, natural fibers have gained research attention in reinforcing polymers due to their availability and unique properties in polymer applications. Preliminary studies indicate indiscriminate disposal of human hair (HH) and the burning of cow hair (CH) and sheep hair (SH) by abattoir operators in Nigeria; this has become a source of concern owing to the hazardous nature of these activities to human health and the environment. This study is, therefore, essential and seeks to utilize these waste materials in an environmentally sustainable way, as the hair fibers used in this work are renewable and will enhance the economy of any country if adequately utilized. The composites of Polypropylene (PP), human, sheep, and cow tail hair fibers were prepared at different weight percentage concentrations of 0, 2, 4, 6, and 8 w% using an injection molding machine. Untreated and treated PP composites were analyzed for average diameter, length, and density; the composites were also characterized for ultimate tensile strength, flexural strength, hardness, and impact strength. The average diameter assessment indicates viz: Cow tail hair > Human hair > Sheep hair. The sequence for hair fiber lengths shows that Sheep hair > Human hair > Cow hair, and the order for average density is Cow tail hair > Human hair > Sheep hair. The analysis of the mechanical properties of the reinforced and unreinforced PP composite showed that the Human hair/PP composite gave the best enhancement for ultimate tensile strength and modulus, flexural strength, and modulus at 8% fiber loading. Cow tail hair/PP composite yielded the best elongation at break at 2% fiber loading. Human hair/PP composite showed the best yield for impact strength at 4% fiber loading, while the Cow tail hair composite performed best for the hardness test at 2% fiber loading. The surface scanning electronic microscope (SEM) images showed no significant manufacturing defect on composites except for the air entrapment in the image of cow tail hair. The study also observed that there is no fiber breakage or void observed in the images. SEM images of the PP-composites interface at 8% maximum loading showed reasonably good fiber adhesion to the polymer matrix. This study is recommended for environmental sustainability and to improve material properties for various applications.

Elsevier Journal of Renewable Energy, 2021

Environmental concerns have increased over environmental hazards associated with fossil energy so... more Environmental concerns have increased over environmental hazards associated with fossil energy source, transition to renewable energy sources have been emphasized, this however requires relevant data for informed decision making. Critical analytical methods in situating bioenergy plants for bioenergy production are advantageous from environmental, economic and sustainable perspectives. A study therefore was undertaken to provide relevant data on biogas renewable energy source using Anambra State of Nigeria as a case study. The study was carried out using the power of Geographical Information System (GIS) technology. Several GIS thematic layers were obtained considering important factors in bioenergy plant location analysis. GIS-based thematic maps used for the production of the suitability map include political boundary map layer, road network layer, Land Use and Land Cover (LULC) layer, Digital Elevation Map (DEM) layer, river layer, slope layer, electric transmission line network layer, biomass potential density layer etc. Considering the fact that bioenergy plant is dependent on heat energy source which is also abundant in the tropics, hill-shade layer was integrated into the GIS location suitability analysis. Various economic and socio-environmental factors were considered and utilized in the development of economic, land suitability and bio-resource spatial density maps. These thematic maps were overlaid to obtain the final suitability map index. The most suitable sites identified were located in Njikoka, Onitsha North and Dunukofia Local Government Areas (L.G.As) of the Study area. The annual cumulative bio-wastes generated from the three LGA are 9,133,220 kg, 3,992,735 kg, and 6,909,450 kg respectively. It is recommended that government and stake-holders should take this study as a veritable tool in green energy technology implementation plan.

Springer, Biomass Conversion and Biorefinery, 2021

Access to affordable clean energy sources as stipulated in United Nations Sustainable Development... more Access to affordable clean energy sources as stipulated in United Nations Sustainable Development Goal (UN SDG) number 7 is important for the development and socioeconomic well-being of people; the need for proper assessment of resources to achieve this goal is indisputable. The goal of this study is to assess the economic feasibility of utilizing an organic fraction of municipal solid wastes (MSW of) using a case study of local government areas (LGA) or Authority for Anambra State of Nigeria for waste to energy project. Smooth adoption of waste to energy projects requires investigation on the economic feasibility parameters necessary for such a project. This study therefore investigated the quantity of organic fraction of MSW, energy recovery and an optimum number of plants considering the economy of scales at the various LGAs of the study area. The result of the study indicates that about 198 tons maximum value of MSW of can be generated daily in Aguata LGA, with an electric energy potential value of 545 MW. The number of plants for the LGAs ranged from 10 to 50 and from 3 to 12 for small-and medium-scale plants. A large-scale plant of about 50 m 3 can possibly be installed at all the LGAs, with a maximum of 4 plants in Idemili and Aguata LGA. The economic assessment based on net present value (NPV) criteria shows poor economic feasibility for a small-scale plant, while NPV was positive for medium-and large-scale plants. The internal rate of return (IRR) ranged from 0.32 to 0.94, with a general increase from small-scale to large-scale economic feasibility. This study can be replicated in other regions; it is suggested that the autonomy of the various LGAs in the country should serve as a major motivation in adopting bio-energy projects independently, and this study will serve as a decision toolkit in the appropriate scale to be adopted.

Elsevier Environmental Challenges, 2023

Recently, natural fibers have gained research attention in reinforcing polymers due to their avai... more Recently, natural fibers have gained research attention in reinforcing polymers due to their availability and unique properties in polymer applications. Preliminary studies indicate indiscriminate disposal of human hair (HH) and the burning of cow hair (CH) and sheep hair (SH) by abattoir operators in Nigeria; this has become a source of concern owing to the hazardous nature of these activities to human health and the environment. This study is, therefore, essential and seeks to utilize these waste materials in an environmentally sustainable way, as the hair fibers used in this work are renewable and will enhance the economy of any country if adequately utilized. The composites of Polypropylene (PP), human, sheep, and cow tail hair fibers were prepared at different weight percentage concentrations of 0, 2, 4, 6, and 8 w% using an injection molding machine. Untreated and treated PP composites were analyzed for average diameter, length, and density; the composites were also characterized for ultimate tensile strength, flexural strength, hardness, and impact strength. The average diameter assessment indicates viz: Cow tail hair > Human hair > Sheep hair. The sequence for hair fiber lengths shows that Sheep hair > Human hair > Cow hair, and the order for average density is Cow tail hair > Human hair > Sheep hair. The analysis of the mechanical properties of the reinforced and unreinforced PP composite showed that the Human hair/PP composite gave the best enhancement for ultimate tensile strength and modulus, flexural strength, and modulus at 8% fiber loading. Cow tail hair/PP composite yielded the best elongation at break at 2% fiber loading. Human hair/PP composite showed the best yield for impact strength at 4% fiber loading, while the Cow tail hair composite performed best for the hardness test at 2% fiber loading. The surface scanning electronic microscope (SEM) images showed no significant manufacturing defect on composites except for the air entrapment in the image of cow tail hair. The study also observed that there is no fiber breakage or void observed in the images. SEM images of the PP-composites interface at 8% maximum loading showed reasonably good fiber adhesion to the polymer matrix. This study is recommended for environmental sustainability and to improve material properties for various applications.

Springer Environmental Science and Pollution Research, 2023

This study evaluated the susceptibility to groundwater pollution using a modified DRASTIC model. ... more This study evaluated the susceptibility to groundwater pollution using a modified DRASTIC model. A novel hybrid multicriteria decision-making (MCDM) model integrating Interval Rough Numbers (IRN), Decision Making Trial and Evaluation Laboratory (DEMATEL), and Analytical Network Process (ANP) was used to investigate the interrelationships between critical hydrogeologic factors (and determine their relative weights) via a novel vulnerability index based on the DRASTIC model. The flexibility of GIS in handling spatial data was employed to delineate thematic map layers of the hydrogeologic factors and to improve the DRASTIC model. The hybrid MCDM model results show that net recharge (a key hydrogeologic factor) had the highest priority with a weight of 0.1986. In contrast, the topography factor had the least priority, with a weight of 0.0497. A case study validated the hybrid model using Anambra State, Nigeria. The resultant vulnerability map shows that 12.98% of the study area falls into a very high vulnerability class, 31.90% falls into a high vulnerability, 23.52% falls into the average vulnerability, 21.75% falls into a low vulnerability, and 9.85% falls into very low vulnerability classes, respectively. In addition, nitrate concentration was used to evaluate the degree of groundwater pollution. Based on observed nitrate concentration, the modified DRASTIC model was validated and compared to the traditional DRASTIC model; interestingly, the spatial model of the modified DRASTIC model performed better. This study is thus critical for environmental monitoring and implementing appropriate management interventions to protect groundwater resources against indiscriminate sources of pollution.

Elseiver Environmental Challenges, 2023

The amount of waste generated in the modern world is constantly on the increase due to world's ur... more The amount of waste generated in the modern world is constantly on the increase due to world's urbanization, industrialization and population increase, thus there is a need to recycle these wastes especially non-biodegradable types. The aim and objective of this research was to produce bio-oil, bio-char, and bio-gas from waste tire using a fixed batch pyrolysis reactor, determine yield at three different temperatures of 400, 550 and 750 °C, determine the calorific value, flash and fire points, cloud and pour points, ash content, moisture content as well as concentration of Zn, Cd, Fe, Cr, Cu, and Pb in the produced bio-oil as well as in the original tire sample. The result shows that the char, oil and gas yields at the three different temperatures analysed for were 62, 24, 14; 48, 36.2, 15.8; and 42, 40, 18 respectively all in weight percent. The char and oil yield was determined by weight measurement, while that of gas was determine by mass balancing. The caloric value of the oil produced was found to be 64.44 KJ/kg, the flash and fire points were found to be 67 and 85 °C while the cloud and pour points were found to be 16 and-3 °C. The ash content and moisture content were found to be 0.04 and 8.18 in weight percent. The heavy metal concentration of the original tire sample was found to be 0.605 Cu, 0.170 Pb, 1.019 Zn, 0.777 Cr, 0.077 Cd and 0.447 Fe while the bio-oil produced contains 0.065 Cu, 0.090 Pb, 0.144 Zn, 2.121Cr, 0.006 Cd and 0.010 Fe all in ppm. This result shows that the rector used has a maximum oil yield of 40% w at 750 °C, and that the oil produced showed decrease in heavy metal concentration when compared to that present in the original tire sample and other petroleum products. Further studies should be conducted to extrapolate the reactor since it produced oil with high thermal stability and caloric value with low ash content and also decreased the heavy metal composition of the oil produced. The heavy metal concentration of other toxic metal should be analysed to further examine its public health risk.

Current Research in Green and Sustainable Chemistry

There is increased enthusiasm towards the use of natural hair fibers for plastic reinforcement du... more There is increased enthusiasm towards the use of natural hair fibers for plastic reinforcement due to their toughness and light weight. In this research, low density polyethylene (LDPE) was reinforced using 0.25 M NaOH treated cow tail, human and sheep hair fibers at 2, 4, 6 and 8% concentration respectively prior to injection moulding. The average densities, diameters and lengths of hair fibres were assessed The results obtained from the analysis of reinforced LDPE composites indicated that cow tail hair gave the highest average density and diameter. Sheep hair had the highest length after grinding. The study also analyzed the ultimate tensile strength and modulus, flexural strength and modulus, elongation, impact and hardness test on the polymer and their composites as well as the morphology and statistical analysis of the composite. This study indicated that human hair LDPE composites achieved highest flexural strength, flexural modulus, ultimate tensile strength and tensile modulus at 8% fibre loading whereas elongation at break and hardness were at 4% fibre loading while impact strength was at 2%. The cow tail hair LDPE composite gave the best impact strength at 8% fibre loading and sheep hair at 6%. The SEM results showed no serious manufacturing defects on the composites. The analysis of variance indicated that only the means of the composites' flexural properties were statistically significant. This study shows that short animal hair fibres could be effectively used to reinforced LDPE, and therefore suggest an alternative waste management strategy of these natural fibres that are currently viewed as environmental nuisance in the study area.

Scientific African

This work explores the use of chito-protein synthesized from fish scale as a bio-coagulant in Aba... more This work explores the use of chito-protein synthesized from fish scale as a bio-coagulant in Abattoir wastewater (AW) treatment. The effect of settling time, pH, adsorbent dosage, and temperature of coagulation on Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), turbidity, and Color from the AW sample were studied. The kinetic study was carried out using four process equilibrium models which are Langmuir, Freundlich, Frumkin, and Tempkin to investigate the mechanism of the reaction. SEM and FTIR spectral analyses were used to evaluate the surface morphology and chemical composition of the bio-coagulant. A low pH, 3 g of dosage in 250 mL vessel, settling period of 30 to 35 min, and temperatures of 323 K for all parameters resulted in the most efficient pollutant elimination. Turbidity, however, had an optimal temperature of 313 K. The result of the study shows that Langmuir model provided the best fit from the equilibrium models compared to Freundlich, Frumkin, and Temkin's models. The experimental data suited the Elovich, Pseudo-first, and Second order kinetic models' analysis and the high values of the regression coefficient of 0.90 supported the idea of perikinetic as the governing mechanism of coag-flocculation in the study. It can be inferred from this study that fish scale as a biocoagulant provides a significant resource for abattoir wastewater treatment.

International Journal of Thermofluids

The dynamics of solid objects falling through a viscous fluid was studied. The forces that contro... more The dynamics of solid objects falling through a viscous fluid was studied. The forces that control the motion as well as the effects of fluid viscosity and object density were studied using an analytical model. Wall effect due to the presence of finite fluid boundaries was evaluated using CFD. Through further correlation of the CFD results, a functional approximation model required to predict the limiting condition for wall effect was developed. The analytical solution gave a good approximation of the forces that control the motion and some indications that the effect of fluid viscosity is paramount in resisting the motion of the solid particle in a viscous fluid. The CFD approach was able to evaluate the system more accurately and allowed for the effects of finite fluid boundaries on the object motion to be calculated successfully. The analytical results agree largely with that of the CFD obtained in the range of vessel internal diameter D ≥ 2m which corresponds to the region where wall-effect is insignificant. The theoretical models were validated using experimental data.

Innovative Food Science & Emerging Technologies

The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help ... more The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help improve the peeling performance of beetroot. MW-assisted IR peeling (MWIR) and IR peeling of beetroot were investigated and compared with the conventional hot-lye peeling method. Also, the effects of these peeling methods on the quality and microstructure were evaluated. Hot-lye peeling at 95 • C for 40 s and 60 s was used as control. Results showed that MW-assisted IR peeling at power 640 W and heating time 7 min produced samples with the highest peelability (99.4%), lowest peel thickness (0.075 mm), and peel remaining (0.8%), lower peeling loss (4.23 g), and better peeling easiness when compared with lye peeling and IR peeling. IR peeling alone produced samples with the lowest peeling loss (2.87 g) and surface colour change, and the highest vitamin C retention (75.32%) than MW-assisted IR and lye peeling respectively. The product microstructure for the different peeling methods showed cellular distortion as a result of thermal expansion. MW pretreatment shows a promising potential to further develop the IR dry-peeling method, to replace the conventional hot lye chemical peeling.

Modeling Earth Systems and Environment

Erosion hazard is a major environmental change in developing countries and therefore necessitates... more Erosion hazard is a major environmental change in developing countries and therefore necessitates investigations for effective erosion control measures. This study is hinged on the numerous advantages of a hybrid Multi-Criteria Decision Model (MCDM) to assess erosion vulnerability using remote-sensed data and the application of Geographical Information System (GIS). Nine risk factors of erosion were selected for this study and their thematic maps were utilized to produce a spatial distribution of erosion hazard in the state. An integrated IVFRN-DEMATEL-ANP model was used to investigate the interrelationships between the risk factors and also obtain their final weights. The assessment model identified Rainfall, Erosivity Index, Stream Power Index, Sediment Transport Index, Topographic Wetness Index, and Soil as the most influential factors of erosion in the study area. The weighted linear combination method was used to integrate the risk factors to produce the spatial distribution of erosion vulnerability model. The method was validated using Anambra State of Nigeria. The findings from the study revealed that Anambra State is vulnerable to erosion hazard with 45% of the state lying between Very High and Medium vulnerable zones. A good predictive model performance of 89.7% was obtained using the AUC-ROC method. The feasibility of integrating the IVFRN, DEMATEL, and ANP models as an assessment model for mapping erosion vulnerability has been determined in this study, and this is vital in managing the impact of erosion hazards globally. The model's identification of hydrological and topographical factors as major causes of erosion hazard emphasizes the importance of critical analysis of risk factors as done in this study for effective management of erosion. This study is a veritable tool for implementation of erosion mitigation measures.

Modeling Earth Systems and Environment

Erosion hazard is a major environmental change in developing countries and therefore necessitates... more Erosion hazard is a major environmental change in developing countries and therefore necessitates investigations for effective erosion control measures. This study is hinged on the numerous advantages of a hybrid Multi-Criteria Decision Model (MCDM) to assess erosion vulnerability using remote-sensed data and the application of Geographical Information System (GIS). Nine risk factors of erosion were selected for this study and their thematic maps were utilized to produce a spatial distribution of erosion hazard in the state. An integrated IVFRN-DEMATEL-ANP model was used to investigate the interrelationships between the risk factors and also obtain their final weights. The assessment model identified Rainfall, Erosivity Index, Stream Power Index, Sediment Transport Index, Topographic Wetness Index, and Soil as the most influential factors of erosion in the study area. The weighted linear combination method was used to integrate the risk factors to produce the spatial distribution of erosion vulnerability model. The method was validated using Anambra State of Nigeria. The findings from the study revealed that Anambra State is vulnerable to erosion hazard with 45% of the state lying between Very High and Medium vulnerable zones. A good predictive model performance of 89.7% was obtained using the AUC-ROC method. The feasibility of integrating the IVFRN, DEMATEL, and ANP models as an assessment model for mapping erosion vulnerability has been determined in this study, and this is vital in managing the impact of erosion hazards globally. The model's identification of hydrological and topographical factors as major causes of erosion hazard emphasizes the importance of critical analysis of risk factors as done in this study for effective management of erosion. This study is a veritable tool for implementation of erosion mitigation measures.

Agricultural Engineering International: The CIGR Journal, 2019

Anambra state is faced with high population explosion and consequently high production of abattoi... more Anambra state is faced with high population explosion and consequently high production of abattoir wastes in major abattoir centres in the state. There is need for strategic waste management in allocation of bio-energy plants to digest these wastes. ArGIS software was used to perform hotspot Analysis to delineate clusters of abattoir potential features with values significantly higher or lower than the overall study area mean or average value. In addition, the set covering location model was used to determine the number of bio-energy treatment plant facilities that should be constructed in the study area and where they should be located. The result of the study indicated that eight abattoirs were classified as hotspot zones/locations (L), and consequently used in the set covering location modelling. The set covering location model indicates that a minimum of two bio-energy plant should be constructed in Obosi (L1) and Umunya (L8) of the study area. The outcome of the study would be...

Innovative Food Science and Emerging Technologies, 2022

The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help ... more The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help improve the peeling performance of beetroot. MW-assisted IR peeling (MWIR) and IR peeling of beetroot were investigated and compared with the conventional hot-lye peeling method. Also, the effects of these peeling methods on the quality and microstructure were evaluated. Hot-lye peeling at 95 • C for 40 s and 60 s was used as control. Results showed that MW-assisted IR peeling at power 640 W and heating time 7 min produced samples with the highest peelability (99.4%), lowest peel thickness (0.075 mm), and peel remaining (0.8%), lower peeling loss (4.23 g), and better peeling easiness when compared with lye peeling and IR peeling. IR peeling alone produced samples with the lowest peeling loss (2.87 g) and surface colour change, and the highest vitamin C retention (75.32%) than MW-assisted IR and lye peeling respectively. The product microstructure for the different peeling methods showed cellular distortion as a result of thermal expansion. MW pretreatment shows a promising potential to further develop the IR dry-peeling method, to replace the conventional hot lye chemical peeling.

International Journal of Thermofluids, 2022

The dynamics of solid objects falling through a viscous fluid was studied. The forces that contro... more The dynamics of solid objects falling through a viscous fluid was studied. The forces that control the motion as well as the effects of fluid viscosity and object density were studied using an analytical model. Wall effect due to the presence of finite fluid boundaries was evaluated using CFD. Through further correlation of the CFD results, a functional approximation model required to predict the limiting condition for wall effect was developed. The analytical solution gave a good approximation of the forces that control the motion and some indications that the effect of fluid viscosity is paramount in resisting the motion of the solid particle in a viscous fluid. The CFD approach was able to evaluate the system more accurately and allowed for the effects of finite fluid boundaries on the object motion to be calculated successfully. The analytical results agree largely with that of the CFD obtained in the range of vessel internal diameter D ≥ 2m which corresponds to the region where wall-effect is insignificant. The theoretical models were validated using experimental data.

Modeling Earth Systems and Environment, 2022

Erosion hazard is a major environmental change in developing countries and therefore necessitates... more Erosion hazard is a major environmental change in developing countries and therefore necessitates investigations for effective erosion control measures. This study is hinged on the numerous advantages of a hybrid Multi-Criteria Decision Model (MCDM) to assess erosion vulnerability using remote-sensed data and the application of Geographical Information System (GIS). Nine risk factors of erosion were selected for this study and their thematic maps were utilized to produce a spatial distribution of erosion hazard in the state. An integrated IVFRN-DEMATEL-ANP model was used to investigate the interrelationships between the risk factors and also obtain their final weights. The assessment model identified Rainfall, Erosivity Index, Stream Power Index, Sediment Transport Index, Topographic Wetness Index, and Soil as the most influential factors of erosion in the study area. The weighted linear combination method was used to integrate the risk factors to produce the spatial distribution of erosion vulnerability model. The method was validated using Anambra State of Nigeria. The findings from the study revealed that Anambra State is vulnerable to erosion hazard with 45% of the state lying between Very High and Medium vulnerable zones. A good predictive model performance of 89.7% was obtained using the AUC-ROC method. The feasibility of integrating the IVFRN, DEMATEL, and ANP models as an assessment model for mapping erosion vulnerability has been determined in this study, and this is vital in managing the impact of erosion hazards globally. The model's identification of hydrological and topographical factors as major causes of erosion hazard emphasizes the importance of critical analysis of risk factors as done in this study for effective management of erosion. This study is a veritable tool for implementation of erosion mitigation measures.