ghanaopendata/ghanaian-research-english huggingface dataset:
Theoretical and experimental insight into the construction of FTO/NiSe2/ BiVO4 photoanode towards an efficient charge separation for the degradation of pharmaceuticals in water

The increasing contamination of water bodies by pharmaceuticals has become a major environmental concern, with traditional treatment methods often proving ineffective. In this manuscript, we present a theoretical and experimental investigation into the construction of an S-scheme FTO/NiSe2/BiVO4 (NSB) photoanode toward the photoelectrocatalytic degradation of pharmaceutical pollutants in water. The study focuses on the optimization of the photoanode structure to significantly restrain charge recombination and maximize photoelectrocatalytic performance. The photoanode achieves higher efficiency (76%) in comparison with the pristine FTO/BiVO4 (BVO) (43%) and FTO/NiSe2 (NS) (17%) for the PEC degradation of ciprofloxacin. This can be attributed to the improved band gap (1.92 eV), low charge transfer resistance (9.6 Ω), reduced flat band potential (0.24 V) and higher charge density (4.86 × 1017 cm–1 ) resulting from synergic interaction at the interface of the semiconductor resulting to fast transition of the charge and restraining of recombination of the charge carriers. The accumulation of the electrons majorly takes place at the NS layer as displayed by the theoretical modeling of the charge density difference. This suggests a transition of electrons from BVO to NS. The band offset as well as the built-in electric field across the NSB interface limit the recombination of the photoinduced carriers. The mechanism including the functions of different reactive species is studied, which reveals that the holes mostly dominate the degradation process. Based on density functional theory, active species capture experiment, and photoelectrochemical detection, the synthesized NSB photocatalyst conforms to an S-scheme heterojunction charge transfer mechanism. We consider the composite suitable for the treatment of water contaminated with pharmaceutical waste.

Source: KNUST
Theoretical studies on mechanisms of some transition metal organometallic reactions

The mechanism of’ three important organometallic reactions catalyzed by transition metals have been studied with semi-empirical PM3(tm) molecular orbital MO) method. The stationary state structures and energetics relevant to the mechanistic pathway are discussed. In the nickel catalyzed Homo-Diels -Alder reactions of Bicyclo [2.2. 1 ] hepta-2,5-diene with electron deficient olefins the PM3(tm) calculations gave geometrical parameters comparable with previous Density Function Theory (DFT) calculations. The calculations indicate that the most energetically favourable reaction pathway is a three step mechanism which involves the direct conversion of the reactant complex 1 to the it—homoaliylic complex 3 followed by electronic rearrangement to give intermediate complex 6 which subsequently undergo reductive elimination to give the deltacyclane product. The activation energies obtained IOI’ the conversion ol reactant complex 1 to the π-homoallylic complex 3, TS (1-3), the conversion ol the 2t—homoallylic complex 3 to intermediate complex 6, TS (3—6). and conversion o[ intermediate complex 6 to the polycyclic adduct, 1’S (6—Pdt.) are 4X. 1 keal molt, 15.9 kcal mol’ and 74.3 kcal mol-1 respectively. In ihe homogeneous polymei-ization ol’ ethylene with ethylene bridged group IV metallocenc catalysts (Q,lI1FICpM — Me and C7H11n7M — Me) the PM3(tm) calculation gave geometric and energetic parameters comparable with previous ab intho and l)ensitv Functional results. The activation energies for ethylene insertion in C,H.41n,M - Me were calculated to be 10.3 kcal mold, 5.0 kcal mol4, 15.0 keal inol and 8.81 kcal mol’, 14.4 keal mol’ and 1 5.8 kcal moV’ for Zirconium, ‘l’itanium and Hafnium respectively. The ö—agostic resting state was found to he the most stable chain orientation in both CH4FlZr! — Bu and C2H4In2Zr - Hu For l)inilrogen cleavage 1w three coordinate Molybdenum (Ill) and Tungsten HI complexes the PM3(tm) calculation yielded geometrica.l parameters and energetics comparable with the results of Density Functional Theory ealcitlati ons by Morokuma et a! and representative experimental parameters. lnergy harriers ol’ 38.8 kcal irol and 51 .6 kcal mol’ were predicted lor 1-I and (.1 ligands respectively i’or the cleavage oithe N—N bond in molybdenum (111).

Source: KNUST
Theological Reflection on Environmental Degradation And Vicious Cycle of Poverty

The poor generally have access only to areas that have higher risk for health and income generation, and they generally lack the resources to reduce the exposure to the risk or to invest in alleviating the causes of such risk. Environmental degradation therefore affects the health and nutrition status of the poor and lower their productivity. The main objective of the study was to examine the Christian attitude towards the environment and vicious cycle of poverty. Interviews and questionnaires were used to collect data from officials of EPA, mining companies, ‘galamsey’ and church members. The study revealed that as people become poorer, they destroy the resources faster. They tend to overuse the natural resources because they do not have anything to eat or any means of getting money except through the natural resources. Poor people often lack sufficient income and education to afford higher quality life. The study further revealed that some communities are denied access to good drinking water due to mining operations. The problems of environmental degradation and water availability has also meant that in some areas, affected communities rely to a great extent, particularly in the dry season, on water sources that are increasingly polluted by chemicals from mining operations. It was realized that maintaining year round access to safe abundant supplies of water was a significant problem for communities affected by mining activities. It was recommended that churches should preach and educate its congregation that the fragile environment on which they depend for their survival is being neglected or over-exploited, and it is now necessary to rehabilitate it and manage it sustainably. It is recommended that there is the need for the churches to have a theological reflection that will help to change their attitude towards the environment. Churches should also teach its members that the environment belongs primarily to them, and v they must take the responsibility for the land and organize themselves in groups, cooperatives, development associations and local associations to defend it. There is also the need for churches to promote a Christian Fund and similar mechanisms for directing funds to environmental awareness projects.

Source: KNUST
A theoretical study of the mechanisms of oxidation ofethylene by manganese oxo complexes†

The mechanisms of oxidation of ethylene by manganese–oxo complexes of the type MnO3L(L=O−, Cl, CH3, OCH3, Cp, NPH3) have been explored on the singlet, doublet, triplet and quartet potentialenergy surfaces at the B3LYP/LACVP* level of theory and the results discussed and compared with thoseof the technetium and rhenium oxo complexes we reported earlier, thereby drawing group trends in thereactions of this important class of oxidation catalysts. In the reactions of MnO3L(L=O−,Cl−,CH3, OCH3,Cp, NPH3) with ethylene, it was found that the formation of the dioxylate intermediate along the con-certed [3 + 2] addition pathway on the singlet potential energy is favored kinetically and thermodynami-cally over its formation by a two-step processviathe metallaoxetane by [2 + 2] addition. The activationbarriers for the formation of the dioxylate and the product stabilities on the singlet PES for the ligandsstudied are found to follow the order: NPH3<Cl−<CH3O−<Cp<O−<CH3. On the doublet PES, the acti-vation barriers for the formation of the dioxylate intermediate for the ligands are found to follow theorder: CH3O−<Cl−<Cp<CH3while the order of product stabilities is: Cl−<CH3O−<Cp<CH3. The orderof dioxylate product stabilities on the triplet surface for the ligands studied is: Cl−<CH3O−<Cp<CH3<NPH3<O−and the order on the quartet surface is O−<Cp<CH3< NPH3<Cl−<CH3O−. The re-arrange-ment of the metallaoxetane intermediate to the dioxylate is not a feasible reaction for all the ligandsstudied. Of the group VII B metal oxo complexes studied, MnO4−and MnO3(OCH3) appear to be the bestcatalysts for the exclusive formation of the dioxylate intermediate, MnO3(OCH3) being better so on bothkinetic and thermodynamic grounds. The best epoxidation catalyst for the Mn complexes is MnO3Cl; theformation of the epoxide precursor will not result from the reaction of LMnO3(L = O−, Cp) with ethyleneon any of the surfaces studied. The trends observed for the oxidation reactions of the Mn complexeswith ethylene compare closely with those reported by us for the ReO3L and TcO3L(L=O−, Cl, CH3, OCH3,Cp, NPH3) complexes, but there is far greater similarity between the Re and Tc complexes than betweenMn and either of the other two. There does not appear to be any singlet–triplet or doublet–quartetspin-crossover in any of the pathways studied.

Source: KNUST
Thermal process evaluation of tuna chunks in a formulated sauce

The effect of various factors on the thermal process parameters and quality attributes of a formulated low-acid canned food (tuna chunks in sauce) were evaluated during thermal processing in a still horizontal batch retort. Sauce was formulated with vegetables, tomato paste, water, oil, corn flour and spices. The sauce was hot-filled (80°C) unto tuna cut into regular shapes and weight, vacuum-sealed in 307x113 cans and subjected to thermal processing. Process variables monitored were retort temperature (115°C,121.l°C and 125°C), solid to liquid ratio (50/50, 60/40 and 70/30) and can headspace (5mm and 10mm) Thermal process parameters (heating rate index, fh, heating lag factor, Jch, cooling rate index, fc and cooling lag factor, Jcc) and the resulting process lethality, Fo and cook value, Co were obtained from time-temperature data during processing for nine consecutive runs. Ball process time (BB) and heating times (Ht) were calculated using the Formula method. Quality attributes (crude protein, crude fat, ash, viscosity, colour and pH) were experimentally evaluated both before and after each run. Can headspace did not have any significant effect (P>0.05) on any of the thermal process parameters. Whereas solid to liquid ratio had significant (P<0.05) influences on fh, Jch and Jcc temperature on the other hand showed significant effect (P<0.05) on Jcc, Fo and Co were both affected significantly (P<0.05) by all the process variables. Ball process time ranged from 55.5-92.1 minutes. Average crude protein, crude fat and ash content in the canned samples were significantly lower than in the raw samples Quality attributes were, however, not adversely altered. The product was stable, commercially sterile and compared favourably with other canned fish products on the market.

Source: KNUST
Thermal conductivity, resistance and specific heat capacity of chemically-treated, widely-used timber for building-envelope

Wood has low thermal conductivity with high thermal resistance and specific heat capacity (SHC). Timber-designed building-envelopes have much resistance to solar radiation, which discomforts occupants. How chemicals alter thermal properties of preservative-treated non-durable woods for housing is inadequately studied. Two preservative-chemicals (Erythropleum suaveolens bark extract and inorganic Maneb/Lambda) influence on the SHC (determined by “method of mixtures”) and, thermal conductivity and resistance (using Lee’s Disc Apparatus) of Ceiba pentandra (a non-durable building timber) was investigated. Stakes treated with E. suaveolens and Maneb/Lambda recorded greater conductivity [(0.005 ± 0.001) × 10-³ and (0.006 ± 0.0006) × 10-³ W/m.K respectively] than C. pentandra control [(0.004 ± 0.0008) × 10-³ W/m.K]. Conductivity was greater in longitudinal surface than radial and tangential directions for all stakes. Thermal resistance of stakes rated as: control [(0.12 ± 0.0008) × 102 – (1.02 ± 0.02) × 102 m2K/W] > E. suaveolens [(0.1 ± 0.002) × 102 – (0.76 ± 0.02) × 102 m2K/W] > Maneb/Lambda [(0.1 ± 0.002) × 102 – (0.73 ± 0.02) × 102 m2K/W]. Maneb/Lambda-treated stakes obtained the greatest SHC [(6810.9 ± 12) × 106 ], then E. suaveolens-treated samples [(5242.1 ± 269.9) × 106 ] and untreated/control [(4014.2 ± 47.8) × 106 ]. Compared to other building materials (e.g., steel, aluminium and concrete), treated stakes have low thermal conductivity, with high thermal resistance and SHC, which is desired as an insulation material. Thus, while chemically-treated timber durability is improved, its insulating capacity to provide thermal comfort in buildings is assured.

Source: KNUST
Thermal properties of selected species of banana grown in Ghana

Banana (Musa acuminata) is an important fruit eaten by most Ghanaians in raw state. The fruit has a very short life span after ripening, hence most are discarded during bumper harvest. Processing will increase its shelf-life and also add value to the product. In order to design equipment, facilities and determine the amount of heat to be added or removed from banana during processing, knowledge of thermal properties of these locally grown bananas of which specific heat, thermal conductivity and thermal diffusivity are vital. The selected varieties for the study were dried to moisture content (MC) ranging from 18.5 – 50.0%wb for gros michel and 34.4 – 65.9 %wb for the medium cavendish. Specific heat was measured by the method of mixtures while the thermal conductivity was measured by the line heat source probe method. Thermal diffusivity was then calculated from the experimental results obtained from specific heat, thermal conductivity and bulk density. Bulk density was measured by the mass per unit change in volume of the sample. The bulk densities for both varieties of banana were found to be in a range of 1376.2 – 1130.0 kg. m-3 and 1233.5 -1065.3 kg. m-3 for the gros michel and medium cavendish varieties respectively, which was found to decrease in with increasing MC. The coefficients of determination were 94.1% and 96.4% respectively for the gros michel and medium cavendish. The specific heat for gros michel variety ranged from 1574 – 2506.8 Jkg-1 oC-1 and that of the medium cavendish variety was 1982.9 – 2970.6 J kg-1 oC-1. The coefficients of determination were 95.4% and 99.9% for the gros michel and medium cavendish varieties of banana respectively. The thermal conductivity of gros michel varied from 0.249 – 0.458Wm-1 oC-1 and that of the medium cavendish also varied from 0.317 – 0.543 Wm-1 oC-1. The LSD and coefficient of determination were 0.0091 and 0.0084; and 98.1% and 97.2% for gros michel and medium cavendish respectively. The thermal diffusivity range for gros michel was 1.15 х10-7–1.62 х10-7m2s-1 and that of the medium cavendish also ranged from 1.29 х10-7-1.7х10-7m2s-1. Specific heat, thermal conductivity and thermal diffusivity were found to increase with increasing MC for both varieties. The effects of MC on all parameters studied were significant at p ≥ 0.05. Regression equations of second order of polynomials were established which could be used to reasonably estimate the values of bulk density, specific heat, thermal conductivity and thermal diffusivity respectively.

Source: KNUST
Thermophysical properties of selected cash crops grown in Ghana

In this thesis, the influence of moisture on selected physical, compressive and thermal properties of cocoa beans, shea and cashew nut and kernel were studied. Standard methodologies that have been accepted internationally and used by several researchers globally were used for the determination of the selected properties in moisture content ranges normally used for the postharvest processing of the selected crops. The results of moisture variationon physical properties of cocoa beans and cashew kernels such as 1000-bean mass,true density, porosity, emptying angle of reposeandstatic coefficient of friction showed increasing trends with linear relationships while bulk density decreased linearly for cocoa bean and cashew kernel samples. The compressive strain and Young’s Modulus for cocoa beans decreasedlinearly with moisture from 0.009 to 0.0045, and 1300 to 205 MPa respectively. However the compressive stress decreased exponentially with increasing moisture content from 1.5 -0.3 MPa while the crushing energy had more positive linear function with moisture content and increased from 0.013 -0.2 J. For shea kernel, compressive stress, compressive strain and Young’s Modulus decreased linearly from 2.0 -0.8MPa, 0.0085 -0.002mm/mm and 2000 –100MPa with increasingmoisture content. Crushing energy increased non-linearly from 0.005 -0.13mJ in the moisture content range of 5% -24% w.b. The compressive stress, strain, and Young’s modulus for the cashew kernel increased from 0.214 -1.214 MPa, 0.355 -0.472 mm/mm, and 2.446 -6.416 MPa respectively as moisture content increased from 5.0 -9.0% wb. Thermal conductivity increased linearly for groundcocoa beans sample from 0.0243-0.0311 W/oCm and for ground shea kernels from 0.0165 -0.0458 W/oCm in the moisturecontent range of 12.59 -43.84%w.b. at a constant bulk density of 295 kg/m3.Specific heat, thermal conductivity and thermal diffusivity for ground cashew kernel were found to increase linearly from 1586 –1756J/kgº., 0.2103 -0.2296W/mK and 2.369×10-7-2.588×10-7m2/s with increasing moisture content from 5.0 -9.0% w.b.

Source: KNUST
‘This disease is not meant for the hospital, it is Asram’: Implications of a traditionally-defined illness on healthcare seeking for children under-5 in rural Ashanti, Ghana

Every child has the right to survive, grow and develop. However, in spite of the considerable global gains that have been made in child survival, Sub-Saharan Africa still has the highest child mortality rates and accounts for the greatest burden of mortality globally. The majority of these children die without ever reaching a health facility. The practice of appropriate healthcare-seeking behaviour has a great potential to reduce the occurrence of severe and life-threatening childhood illnesses. Several factors, however, influence healthcare-seeking behaviour, including perceptions of the cause of illness and socio-cultural perspectives. This study seeks to understand local concepts of a traditionally-defined illness complex, Asram, and its influence on healthcare seeking behavior of mothers/caregivers. This qualita tive study was conducted from October 2019 to February 2020. Four Focus Group Discus sions were conducted with mothers/caregivers of children under-5 and 22 Key Informant Interviews with mothers/caregivers of children who had Asram, health workers at district, facility, and community levels, and Asram healers. Participants were selected from two rural communities, Akutuase and Wioso of the Asante Akim North district in the Ashanti region of Ghana. Data analysis was carried out iteratively throughout data collection, using a thematic analysis approach. The study shows that Asram is a childhood illness complex that is per ceived to have been acquired spiritually and/or inherited. Nine types of Asram were described. This childhood illness was said to be treatable by Asram healers who had sub specialties in treatment approaches that were determined by the Asram type reported. Mothers/caregivers trusted Asram healers and preferred to call on them first. This was found to be the main reason for delays in seeking healthcare for children under-5 who showed symptoms of Asram. Asram is a childhood illness complex that is believed to be bet ter managed outside the health facility setting. This study complements existing knowledge

Source: KNUST
This disease is not meant for the hospital, it is Asram’: Implications of a traditionally-defined illness on healthcare seeking for children under-5 in rural Ashanti, Ghana

Every child has the right to survive, grow and develop. However, in spite of the considerable global gains that have been made in child survival, Sub-Saharan Africa still has the highest child mortality rates and accounts for the greatest burden of mortality globally. The majority of these children die without ever reaching a health facility. The practice of appropriate healthcare-seeking behaviour has a great potential to reduce the occurrence of severe and life-threatening childhood illnesses. Several factors, however, influence healthcare-seeking behaviour, including perceptions of the cause of illness and socio-cultural perspectives.This study seeks to understand local concepts of a traditionally-defined illness complex,Asram, and its influence on healthcare seeking behavior of mothers/caregivers. This qualitative study was conducted from October 2019 to February 2020. Four Focus Group Discus sions were conducted with mothers/caregivers of children under-5 and 22 Key Informant Interviews with mothers/caregivers of children who had Asram, health workers at district, facility, and community levels, and Asram healers. Participants were selected from two rural communities, Akutuase and Wioso of the Asante Akim North district in the Ashanti region of Ghana. Data analysis was carried out iteratively throughout data collection, using a thematic analysis approach. The study shows that Asram is a childhood illness complex that is perceived to have been acquired spiritually and/or inherited. Nine types of Asram were described. This childhood illness was said to be treatable by Asram healers who had subspecialties in treatment approaches that were determined by the Asram type reported. Mothers/caregivers trusted Asram healers and preferred to call on them first. This was found to be the main reason for delays in seeking healthcare for children under-5 who showed symptoms of Asram. Asram is a childhood illness complex that is believed to be bet ter managed outside the health facility setting. This study complements existing knowledge and creates opportunities for further research and the introduction of more effective interventions in the effort to improve child survival in rural communities.

Source: KNUST
A three-state Markov Chain Model of plasmodium falciparum parasitemia transmission in Ghana

In this thesis, a three state Markov chain model is used to describe the malaria transmission dynamics, using Ghana data from the Ghana Health Service and World Health Organization. The states of the model are defined as susceptible, Infected and dead and the time step for a transition to occur is defined as 8 days. The model is based on the assumptions that individuals are transferred at constant rate between states, and that only one transition is possible between two consecutive surveys. The model is used to determine the steady state probability distributions, the life expectancy of an individual and finally the results are interpreted in terms of malaria control issues. The expected time to a first infection is found to be 11 days and the total duration of the disease (non severe) is found to be 17 days. The life expectancy from the onset of the survey is found to be 55 years for both individuals who are initially infected and those who are initially susceptible.

Source: KNUST