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A long essay or dissertation or thesis involving personal research, written by postgraduates of University of Ghana for a university degree.
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Item Institutions and African Economic Development(Working Paper, 2022) Fosu, A.K.In light of the increasing importance of institutions in economic development and Africa’s desire to catch up, the present paper provides an account of this crucial subject, ‘Institutions and African Economic Development. First, adopting the usual definition of ‘institutions’ as ‘rules of the game’, the paper shows that improvements in economic institutions, such as economic freedom, had begun by the early 1990s, and accelerated about the mid-1990s, consistent with observed improvements in economic and development outcomes. Also improved are measures of political institutions: an index of electoral competitiveness, constraint on the executive branch of government, and polity 2 as an indicator of the level of democracy, beginning in the late 1980s or early 1990s. Second, based primarily on a review of the extant literature, the paper observes that these improvements in the measures of economic and political institutions are positively associated with the increasing economic development in Africa. Third, indicators of institutional instability, measured by the frequency of civil wars and the incidence of coups d’etat, have been diminishing since the early 1990s, with implications for improved growth and human development. Fourth, some evidence is provided in support of the notion that African countries with better performance on institutional quality during the period of growth resurgence have also exhibited greater progress in poverty reduction. Finally, the paper concludes by flagging the potential risk of African countries backtracking on their respective trajectories toward achieving the democratic consolidation required to sustain the gains in growth and development.Item Ensemble learning prediction of transmittance at different wavenumbers in natural hydroxyapatite(Scientific African, 2020) Okafor, E.; Dodoo-Arhin, D.; Obada, D.O.Material engineering-based research has often relied so much on tedious human exper iments for generating specific engineering properties with a major draw-back of high time demand that can span between an hour and days. Hence to deviate from the usual paradigm, we provide an alternative approach which employs artificial intelligence (AI) based ensemble learning methods for predicting the degree of transmittance for a range of wavenumbers of infrared radiation through hydroxyapatite (HAp) samples. The effective samples (transmittance and wavenumber) were passed as input to the predictive systems. For this, we trained two ensemble learning methods: Extreme Gradient Boosting (XGBoost) and Random Forest on variants of HAp (density and time variations), while considering a fixed amount of 10,000 base estimators. The results show that Random Forest marginally outperforms the XGBoost in the testing phase but requires a much longer computing time. However, XGBoost is much faster than the Random Forest. Furthermore, the examined en semble learning models yielded a coefficient of determination (R2 > 0.997): which are in close agreement with experimental data, depicting an excellent generalization capacity. Additionally, the examined ensemble learning models showed a significant ≥ 99.83% de crease in computational complexity relative to the time spent when generating the exper imental data. Overall, the use of ensemble learning models is very important for validating material engineering propertiesItem Photocatalytic degradation of Rhodamine dyes using zinc oxide nanoparticles(Materials Today: Proceedings, 2020) Dodoo-Arhin, D.; Asiedu, T.; Agyei-Tuffour, B.; et al.This paper presents the synthesis of nanocrystalline zinc oxide (ZnO) particles via the sol-gel method using zinc acetate as a precursor. The calcination temperature of the ZnO was varied to determine its effect on particle size. The resultant samples were characterized using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UltraViolet–visible Spectroscopy (UV–Vis) and Scanning Electron Microscopy (SEM). Nanocrystalline wurtzite ZnO particles with crystallite sizes ranging from 16 nm to 30 nm were produced. The Energy Band gap of the synthesized zinc oxide nanoparticles decreased with increasing calcination temperature and crystallite size. SEM Micrographs showed rice-like microstructure morphology of ZnO nanoparticles. The usage of the ZnO nanoparticles as a photocatalyst was also explored in the degradation of Rhodamine B dye using UV light, with particular attention paid to the effect of particle size and catalyst load on the degradation efficiency of the dyes. The nanoparticles calcined at 400 C with a crystallite size of 16 nm resulted in the highest degradation efficiency of 95.41% when 0.2 g catalyst loading was applied. 2019 Elsevier Ltd. All rights reserved. Selection and peer review under the responsibility of the scientific committee of the International Symposium on Nanostructured, Nanoengineered, and Advanced MaterialsItem Hydroxyapatite ceramics prepared from two natural sources by direct thermal conversion: From material processing to mechanical measurements(Materials Today: Proceedings, 2020) Akpan, E.S.; Dodoo-Arhin, D.; Dauda, M.; et al.In this study, hydroxyapatite (HAp) was extracted from catfish bones (CB) and non-separated animal bones (NB). The bioceramic samples were prepared by a facile synthesis route and the representative scaffolds were prepared by cold compaction and sintered at 900 C, 1000 C, and 1100 C. To evaluate the properties of the produced HAp, X-ray diffraction (XRD) and Fourier Transform Spectroscopy (FT IR) analyses were carried out. The evaluation of the hardness of the representative bio-derived scaffolds was experimentally conducted while the fracture toughness and brittleness index were obtained by calculation using the hardness test parameters. The experimental data showed that as temperature increased up to 1000 C for CB, there was a consequential increase in hardness, while for NB, hardness values reduced throughout the sintering regimes. These gradients in mechanical measurements are ascribed to phase changes during heat treatment. 2020 The Authors. Published by Elsevier Ltd. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by nc-nd/4.0). Selection and Review under the responsibility of the scientific committee of the International Conference & Exposition on Mechanical, Material and Manufacturing TechnologyItem Modified nanostructured titania photocatalysts for aquatic disinfection applications(Materials Today: Proceedings, 2020) Dodoo-Arhin, D.; Bowen-Dodoo, E.; Agyei-Tuffour, B.; et al.According to SDG 6, everyone on earth should have access to safe and affordable drinking water. In sharing water-treatment technologies that lead to accomplishing this goal, it is imperative to devise ways of removing microbial contaminants such as E. coli from drinking water, especially in resource-limited settings that lack centralized water supply systems. One of the approaches is bacterial disinfection of water at the point of use. In this study, the bactericidal effects of the photocatalysis of titanium dioxide-based nanoparticles under UV and visible light are explored. Pristine and silver doped nanostructured mesoporous titanium dioxide (Ag-TiO2, TiO2) particles with high specific surface area and average crystallite domain size of 7.0–7.5 nm were prepared using the simple and cost-effective sol-gel technique followed by thermal treatment. The addition of Ag+ ions during the hydrolysis/condensation of the Ti(IV) molecular precursor led to the homogeneous dispersion of the Ag+ cations on the titania matrix. The As-prepared nanoparticles were characterized using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), thermogravimetry, Fourier Transform Infra-Red (FTIR), and Raman Spectroscopy. X-ray diffraction, FTIR, and Raman spectroscopy confirmed that the crystalline structure of the TiO2 matrix corresponds to the anatase polymorph; however, the presence of the dopant led to an increase in the system disorder due to the rise in the concentration of oxygen vacancies. The As-prepared nanoparticles were used for Escherichia coli (E. coli) inactivation under dark and UV–visible light conditions. Under dark conditions, Ag-doped titania and pristine titania resulted in 95% and 64% E. coli population inactivity while under light conditions, 99% and 97% degradation respectively were observed. Taken together, these results demonstrate that, the synthesized TiO2 nanoparticles have promising applications in the light-mediated point-of-use inactivation of bacterial contaminants in water. 2019 Elsevier Ltd. All rights reserved. Selection and peer review under the responsibility of the scientific committee of the International Symposium on Nanostructured, Nanoengineered, and Advanced Materials.Item Effects of substrates on the performance of optoelectronic devices: A review(Cogent Engineering, 2020) Asare, J.; Agyei-Tuffour, B.; Dodoo-Arhin, D.; et al.This review discusses the effects of substrates on devices fabricated for optoelectronic applications. It includes the types and characteristics of substrates, synthesis, and fabrication of substrates, and the influence of substrates on the optical properties, surface morphology, and current-voltage behavior of optoelectronic devices. The study showed that two main types of substrates: planar and textured are commonly used in the industry. Flexibility, semi-rigidity, and rigidity are characteristics of the substrates and they vary in modulus, transparency, and texture. Whereas glass and metal substrates can be produced via melt casting, polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), etc are produced by crosslinking polymer base materials with curing agents. The mechanical and current-voltage characteristics are also shown for planar and textured substrate-based devices. The textured substrates showed ridges, wrinkles, and buckled surface morphology whereas the planar showed uniform and largely flat morphology. Textured substrates also recorded higher optical absorbance and improved device efficiencies than planar substrates. The molecular configuration of the polymer chains is edged-on for planar substrates and edge-on and face-on for textured substrates. The findings and their implications have been discussed to highlight the importance of substrates in the fabrication and performance of optoelectronic devices.Item Exploratory study of the electrochemical properties of local cassava starch as a potential green and sustainable polymer binder for energy storage application(MRS Advances, 2023) Mohammed, L.; Doodo‑Arhin, D.; Agyei‑Tufour, B.; et al.The need to develop an aqueous-based binder has dominated research publications for some time now. The application of this man-made aqueous-based binder in LIBs has the potential to reduce the environmental impact of LIB. In this preliminary study, local cassava starch is treated and prepared as a polymer binder for LIBs application. The binder is applied in lithium nickel manganese cobalt oxide electrodes as a cathode in LIBs. The electrodes displayed a discharge capacity of 142 mAh/g and 73 mAh/g for LiNMCO-442/Cassava starch and 139 and 28 mAh/g for LiNMCO-442/PVDF at 0.1 C-rate and 10 C-rate respectively. After 100 cycles, the LiNMCO-442 cells retained about 80.2 and 65.5% of the cells with cassava starch binder and PVDF binder, respectively, at room temperature. The fairly electrochemical performance of the local cassava starch makes it a potential alternative to the petroleum-based binder, PVDF.Item Prediction of the reflection intensity of natural hydroxyapatite using generalized linear model and ensemble learning methods(Engineering Reports, 2020) Okafor, E.; Dodoo-Arhin, D.; Obada, D.O.; Ibrahim, Y.Laboratory data acquisition and analysis of X-ray diffraction (XRD) data involves a lot of tedious human engineering and is time-consuming. To put it in context, a summation of the material synthesis procedure leading to the analysis of the structure of the material can span several days. To curb this challenge and to enhance innovations in engineering pedagogy, this article investigates an alternative method that uses supervised learning algorithms based on ensemble techniques and a generalized linear model (GLM) for predicting reflection intensity (XRD patterns) of raw and natural hydroxyapatite under varying sinter ing temperature conditions given Bragg angles as input to the machine learning algorithms. For the experiment, we trained GLM and ensemble learning models (CatBoost, LightGBM, and two variants of XGBoost based on manual and genetic algorithms for tuning the hyperparameters). The results show that most instances of the XGBoost yielded a robust performance that surpasses all other approaches when predicting X-ray reflection intensities ascribed to the biomaterials subjected to varying sintering temperature conditions. In addition, the results show that all the ensemble techniques significantly outperform the GLM indicates that the former exhibits better generalization capacity. The ensemble learning techniques and the GLM present a reduced computational complexity.Item Body size estimation and weight management practices in urban poor communities in Ghana: A cross-sectional study(Journal of Health and Social Sciences, 2020) Frempong, G.A.; Anarfi, J.K.; Badasu, D.M.; Codjoe, S.N.A.Body size perception is a pertinent issue globally due to its implications for weight management. This study examined the influence of body size estimation on weight management behaviors in urban poor areas of Ghana. Methods: A cross-sectional design was used to collect data among a sample of 395 adults aged 18-70 years. A semi-structured questionnaire was designed for the collection of data on socio-demographic characteristics, weight perceptions, and weight management strategies. Anthropometric measurements were also taken, using standard procedures. Logistic regression models were used to examine relationships among the va variables. Results: More than half (57%) of the total sample was overweight or obese and 56.7% of the participants accurately estimated their body size. Nearly a third (37%) of the participants intended to stay about the same weight, while 29.6% and 11.9% wanted to lose or gain weight, respectively. To achieve their weight management goals, 60.3% of the participants engaged in healthy weight management practices. Body size estimation had no statistically significant relationship with weight management practices. However, the likelihood of engaging in healthy practices increased as age increased (OR = 1.021; 95% CI: 1.000 to 1.042). Individuals who belonged to households of the upper wealth category were less likely than those in lower wealth households to engage in healthy practices (OR = 0.548; CI: 0.330 to 0.911). Community of residence, a community conducive to physical activity and social support also significantly predicted weight management practices. Conclusion: The findings of this study highlight the importance of age and some socio-environmental factors in public health strategies for weight management.Item Towards Social Justice Consciousness in Ghana’s Higher Education: Revisiting the Thoughts of Nkrumah and Nyerere(Journal of Interdisciplinary Studies in Education, 2021) Amuzu, D.This article revisits the thoughts of Kwame Nkrumah and Julius Nyerere on decolonizing higher education in Africa. Their critique of colonial higher education centers on the notion that it was designed to promote the economic aspirations of the colonial metropolis, making it socially unjust, culturally irrelevant, and developmentally inapt. For redemption, African universities should align with the aspirations of their societies and promote African cultural consciousness. Their value-laden thoughts are classified into themes, discussed, and consequently recommended as ideas for policy considerations because they are yet to firmly influence Ghana’s higher education policy framework despite their relevance. The themes are: liberating the African mind; nurturing African character; owning the African narrative; and the essence of knowledge.