ghanaopendata/ghanaian-research-english huggingface dataset:
Investigation of structural and radiological shielding properties of pozzolana-portland cement

The physical properties of the ordinary Portland cement (OPC) are enhanced when the matrix of the OPC is partially replaced by admixtures such as Pozzolana. This research investigated the radiological shielding properties and the structural strength of Pozzolana-Portland Concrete (PPC) at different ratios of 0% (S0), 10% (S1), 20% (S2), 30% (S3), 40% (S4), 50% (S5), 60% (S6), 70% (S7) and 80% (S8) of Pozzolana. Radiological shielding property of a material is its ability to shield or absorb ionizing particles/rays; thus preventing it from being released into the environment when a source thereof is housed in containment. Ionizing radiations are found in nuclear reactors, γ-rays and x-rays equipment used in energy and health sectors. They are also found in sources used in quality assurance industries. Compression test was performed using CONTROL electronic type compressiontesting machine. Test samples were made of concrete (mixture of Portland and Pozzolana cement) cubes and cylinders. The experiments were conducted at a temperature of 27 ± 2 o C at the following days of aging; 2, 7, 14 and 28. The compression test results showed that concrete of Portland-Pozzolana cement (PPC) at 20% Pozzolana has more compressive strength than that of the ordinary Portland cement at 28 days of curing. Flexural and ultrasonic tests were conducted to confirm the results. Neutron activation analysis (NAA) was also carried out to determine the elemental compositions of Pozzolana and ordinary Portland cement. The neutron activation analysis results showed that Europium, Hafnium, Copper, Calcium, Iron, Cobalt and Aluminum, all of which have significant macroscopiccross sections (shielding properties) dominating more in Pozzolana cement than in the ordinary Portland cement. X-ray shielding analysis was carried out toascertain the veracity of the NAA results. Linear attenuation coefficient (µ l ) of each sample at photon energy of 0.15 iv MeV was determined with the 50% PPC showing highestvalue. Further, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses were performed to identify the phases contributing to the highest strength at 20% PPC (33 MPa) and highest shielding, µ lat 50% PPC (1.533 cm -1 ). The results in all showed that Pozzolana positively affects structural and radiological shielding properties of the ordinary Portland cement (OPC), since the OPC (Control) concrete had a compressive strength of 28.44 MPa at day 28 and a linear attenuation coefficient (µ l ) of 0.140 cm -1 . The XRD results showed that Calcite (CaCO3), which is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3) accounts for the very high strength in the 20% PPC while Iron (Fe), Copper (Cu), Manganese (Mn) and Aluminum Hydroxide (AlHO2) account for the very high shielding ability of the 50% PPC.

Source: KNUST
Investigation of Okra Pectin at Different Harvest Maturity

Okra (Abelmoschus esculentus) is a staple vegetable in Ghana and several African countries but underutilized. The mucilage or pectin content is currently of interest for various food and non-food applications. The objective of this work was investigate the yield and intrinsic viscosity of okra pectin extract as influenced by fertilizer application and maturity of the fruit pods. Isolation of okra pectin was done by an aqueous extraction at pH 6.0 from the pods of 2 different okra genotypes at three harvest maturity and two different weight of NPK applications (6g and 9g). The intrinsic viscosity [η] of the okra pectin solutions was determined at 20oC with a Ubbelohde capillary viscometer and calculations made according to the Huggins equation. Pectin yield ranged between 8-24% depending on genotype, fertilizer treatment and maturity of the fruits. There were significant differences (p < 0.05) in the pectin yield between the okra genotypes as well as among the stages of maturity of the okra fruits. Interaction between okra varieties and the stages of maturity of fruits was also significant for pectin yield. The pectin yield of AGRA genotype was higher than that of AGBAGOMA. However, the intrinsic viscosity of pectin of AGBAGOMA was higher than that of AGRA. Highest pectin yield was observed for intermediate matured fruits, followed by that of immature fruits and lowest was observed for overgrown fruits. The intrinsic viscosity values however was highest for immature fruits as compared to the intermediate and overgrown okra fruits. Pectin yield and intrinsic viscosity increased significantly with fertilizer application (p < 0.05). The present findings show that harvesting at intermediate maturity would be most appropriate if high pectin yield is desired. A 9g NPK treatment suggest the opportunity to increase yield and intrinsic viscosity of okra pectin. The study showed that it is important to identify the most appropriate stage of development to harvest the okra fruit for maximize pectin yield. The results of this study suggest that intermediate fruit maturity would be most appropriate to harvest okra fruits to increase pectin yield.

Source: KNUST
Investigation of Superluminal Motion of Free Spin-half Particles in Spacetime

The possibility of free spin-1/2 particles (also called Dirac particles) superluminal motion in spacetime, is investigated. The universal cover of the entire Lorentz group L consists of SL(2, C) and the spinor map so that to obtain a relativistically invariant description of the state of an electron, one looks to the representations of SL(2,C), that is, to the 2-valued representation of L, known as spinors. We restrict our approach to realistic one-particle systems along with the “positive energy” and utilize the free Dirac waves propagating in the z−direction. The Dirac wave function ψ (x,t) is considered as a “classical field” and the corresponding wave equation is derived from a symmetrized Lagrange function. It is observed that variation in spin angular momentum (in the light cone) leads to causality violation, whereas variation in orbital angular momentum does not. Consequently, it is shown that the expectation value of the generalized translational relative velocity component of a free spin-half field indeed exceeds the speed of light. This result is also feasible in a fiber bundle formalism.

Source: KNUST
Investigation of synergistic effects of extracts from Erythrophleum suaveolens, Azadirachta indica, and Chromolaena odorata on the durability of Antiaris toxicaria

The service life of non-durable wood can be extended with inorganic preservatives, but several are harmful to the environment and non-target organisms. Recently, eco-friendly types from organic sources including plants have been used. The influence of bark extracts from Erythrophleum suaveolens and Azadirachta indica, and leaf extract from Chromolaena odorata, singly and in combinations (all at 1.5%) was investigated in field performance tests with non-durable Antiaris toxicaria wood. Treated and control stakes (500 50 25 mm) were exposed for 5 years. Data included extract retention, visual durability ratings, and mass and hardness losses. Retention was greatest for mixed E. suaveolens and C. odorata extract and least for single E. suaveolens extract. For durability parameters, non-treated stakes performed worse than treated ones. E. suaveolens bark-treated stakes were most durable; those treated with mixtures containing E. suaveolens also performed well, while stakes treated with other mixtures performed similarly to the controls, except for hardness. The mixed extracts exhibited various effects. For retention, synergism exists between E. suaveolens and C. odorata, there was antagonism between A. indica and C. odorata, while E. suaveolens extract reduced the retention of A. indica. Regarding durability, no synergism existed between effects of the mixed components. However, E. suaveolens bark extract enhanced A. indica, and C. odorata ingredients, while the effect of E. suaveolens extract was suppressed when it was mixed with the others. These extracts are potential alternatives for inorganic preservatives, especially E. suaveolens and its mixed extracts, as its effects enhanced the others.

Source: KNUST
An investigation of the contract management system for community based infrastructure projects – A Case Study of Social Investment Fund - SIF

The Ghana Poverty Reduction Strategy (GPRS), initiated in 1998, led to the institution of the Social Investment Fund (SIF) which has been providing social, infrastructure and economic services to communities within Ghana. The infrastructure provided under the SIF include classroom blocks, school workshops, libraries, community clinics, teachers’ and nurses’ quarters, water and sanitation projects. Social Investment Fund (SIF) infrastructural projects are community based which are demand driven by the communities. Globalisation, advances in technology, coupled with the increasing demand for quality and changes in the economy are some of the challenges facing the Construction Industry. As variety of projects is implemented by these bodies through community contracting, there is the need for the various stakeholders to cooperate as a seamless provider of design, construction and maintenance services. To this end, a good contract management system for SIF will provide a properly laid down and adequate procedure for procuring community based donor funded infrastructural projects with the aim of value for money and achieving project objectives. The study employed a questionnaire survey of 180 major stakeholders of SIF using systematic and purposive sampling techniques. This included 72 contractors, 8 consultants and 100 zonal officers, community elders and District Assembly Officers. Descriptive analysis and the one sample T-test were employed in the analysis of the data obtained from the field. The findings show that SIF has no formal system of contract management and respective beneficiaries are usually left to design their respective systems of managing the implementation the sub-project. SIF awards contracts to all classes of contractors depending on the size of the projects. Community involvement in SIF projects has usually been limited to community contributions. SIF do not organise any formal training and education for communities. It is recommended that SIF must establish a desk for contract management specialist (CMS) at the FMU who will be solely responsible for the development and review of all sub-projects on matters relating to contract management. SIF must develop more effective working relationship between all parties to enable proper co-ordination and monitoring of the sub-projects.

Source: KNUST
Investigation of Superluminal Motion of Free Spin-half Particles in Spacetime

The possibility of free spin-1/2 particles (also called Dirac particles) superluminal motion in spacetime, is investigated. The universal cover of the entire Lorentz group L consists of SL(2; C) and the spinor map so that to obtain a relativistically invariant description of the state of an electron, one looks to the representations of SL (2;C) ; that is, to the 2-valued representation of L; known as spinors. We restrict our approach to realistic one-particle systems along with the \positive energy" and utilize the free Dirac waves propagating in the z􀀀direction. The Dirac wave function (x; t) is considered as a \classical fi eld" and the corresponding wave equation is derived from a symmetrized Lagrange function. It is observed that variation in spin angular momentum (in the light cone) leads to causality violation, whereas variation in orbital angular momentum does not. Consequently, it is shown that the expectation value of the generalized translational relative velocity component of a free spin-half field indeed exceeds the speed of light. This result is also feasible in a fi ber bundle formalism.

Source: KNUST
Investigation of the Onset, Cessation and Length of the Rainy Season over Ghana

This study seeks to investigate the onset, cessation and length of the rainy season using a simulated rainfall data from the fourth generation Regional Climate Model (RegCM4) and measured rainfall data from the Ghana Meteorological Agency (GMet) over Ghana from 1998 to 2012. The results from the RegCM4 was compared with those derived from the measured rainfall data. The results showed that the mean rainfall onset dates for the Forest, Coastal, Transition and Northern zones of the country, from the RegCM4 was calculated to be 31st March, 4th April, 13th April and 2nd May respectively. The GMet measured rainfall values also had the mean rainfall onset dates determined to be 27th March, 27th April, 8th April and 27th April for the Forest, Coastal, Transition and Northern zones. The mean rainfall cessation dates from the RegCM4 was recorded to be 2nd November for the Forest zone, 29th October for the Coastal zone, 15th November for the Transition zone and 20th October for the Northern zone. The mean rainfall cessation dates from the GMet measured rainfall values was also determined to be 16th November for the Forest zone, 3rd November for the Coastal zone, 24th November for the Transitional zone and 9th November for the Northern zone. The average length of the rainy season from the RegCM4 was computed to be about 216 days for the Forest zone, 209 days for the Coastal zone, 216 days for the Transition zone and 171 days for the Northern zone. The GMet rainfall measured data also measured similar average lengths of 234 days for the Forest, 191 days for the Coastal zone, 230 days for the Transition zone and 196 days for the Northern zone. These results may have very useful applications for water resource management and food security in Ghana.

Source: KNUST
An investigation of the random walk hypothesis of stock prices on the Ghana stock exchange.

The aim of this thesis is to investigate whether or not stock prices at the Ghana Stock Exchange follow a random walk model. There have been immersed developments in the Stock market all over the world in the past. There have also been numerous changes in the stock market in both developed and developing countries. This research aims at investigating whether or not stock prices at the Ghana Stock Market follows a random walk model. The Ghana Stock exchange financial markets returns series portrays volatility clustering that shows an indication of inefficiency on the Ghana Stock Exchange. The result of both the parametric and the non-parametric test shows that returns from the Ghana Stock Exchange did not follow a normal distribution. The study uses two test of randomness and independence based on serial correlation test to check for the presence or otherwise of auto correlation in the daily stock prices and returns from the Ghana Stock Market. The entire test including the Z-score value for both stock prices and their returns show significant indications of dependence in return series hence, non-randomness. The overall findings suggest that random walk model cannot be a good description of successive price returns at the Ghana stock Exchange and hence results obtained are contrary to the hypothesis that successive stock price are independent random variables and also not consistent with efficient market hypothesis.

Source: KNUST
Investigation of water quality used by communities in the Savelugu- Nanton District of the Northern Region, Ghana

Communities in Savelugu-Nanton district depend on boreholes, hand-dug wells pipe borne water and dams. The objective of this study was to investigate the drinking water quality of these sources between January 2013 to June 2013. Three hundred and thirty six (336) water samples were collected from boreholes, hand-dug wells, dams and tabs for laboratory analysis. Total coliform and faecal coliform were enumerated using the membrane filtration method. Physico-chemical parameters such as total hardness, phosphate, chloride, total alkalinity, fluoride, nitrate, iron, manganese, magnesium, calcium, sodium, dissolved oxygen, total dissolved solids and conductivity were determined in the laboratory. Temperature, turbidity, pH were also determined in the field. The result showed that higher coliform counts were recorded for dams and hand-dug wells but very low counts in the boreholes and zero counts for pipe borne water. Values recorded for all physico-chemical properties were within world health organisation (WHO) guideline values except turbidity values for the dams and iron concentration for hand-dug wells and dams in the district. The ranking in terms of quality from the research are in the order; pipe borne water> bore hole water > hand-dug well water > dam water. Water from shallow hand dug wells and dams upon which the communities depend is of poor quality as these are sited close to refuse pits, latrines and areas accessible to domestic animals. Generally, some water samples had values of the physico-chemical properties lower than world health organisation (WHO) guideline values indicating the acceptability of the water for domestic use, but for the biological properties, turbidity and iron in dams need further treatment before they will be safe for domestic use.

Source: KNUST
Investigations into merchants adoption of online payment systems and the barriers to its implementation in Ghana

For some years of technological advancement, the internet has progress from a specific tool for IT pros and computer geeks to a daily destination for business men and women all over the world. Inarguably, technology has made our lives easier. Electronic business has been forecasted to be a new agent of economic growth for developing countries. Online payment systems are emerging technologies that offer unique learning opportunities for contemporary and international businesses. This thesis investigates into merchants' adoption of online payment system. it also looks at the possible barriers that impedes its implementation in Ghana. It particularly seeks to explore whether merchants in Ghana make use of online payment system, and to identify barriers that affects its promotion in Ghana....

Source: KNUST
Investigations into the quality of mill plate wear using attrition mills in Ghana.

Attrition mills are machines used for size reduction (grinding) of fibrous material especially agro-food produce such as maize, millet sorghum, cassava chips, pepper etc., into a desirable flour sieve size. In the Attrition mill, two roughened disc with teeth or grooves, which are made from cast iron are mainly engaged for the grinding. Observation has proven that the teeth wear out rampantly during milling. Hence the objective of the work was to investigate, identify the causes of wear and develop a solution technique to rectify the problem. The method used for the study included the purchased of grinding disc samples from known foundries at Suame Magazine Industrial Area in Kumasi. The samples were prepared and their elemental compositions were determined at Tema Steel Works (TSW). The specimen was compared to ascertain the correlation between the elemental composition, and the foundry practices. The dial indicator was used to determine the parallelism and concentricity of the mill plates. Soaked maize was milled using the grinding disc samples. The resulting flour sample was taken to GAEC laboratory and analyzed to determine the amount of iron particles present. Results indicated that hardness of the grinding mill plates was deduced from the depth of penetration using Brinell hardness method and there was a moderately strong correlation between wear and hardness. The hardness values obtained ranged between 429 BHN and 534 BHN and the penetration values were between 2.65 mm and 2.95 mm. It was established that, the lesser penetration the greater the value of the hardness and the lesser the wear. It was shown that, the wear rates ranges from 1.5×〖10〗^(-3) kg/min to 5.167×〖10〗^(-3) kg/min. From the analysis, it was established that significant metals particles existed in the milled flour. The study revealed that heavy metal particle was found in the mill flour with values ranging from 14.71 mg/kg to 21.55 mg/kg of flour. For the limit of contaminants levels, Asare and Nulux indicated an average value of 50 %. Abudia and Atanga were 100 % below the contaminant limits, suggesting a good standard. Navin and Babawala having 75 % above the contaminants limits indicating poor standard. It could be concluded that the relationship between wear rate of 1.5×〖10〗^(-3) kg/min to 5.167×〖10〗^(-3) kg/min, hardness value of 429 BHN and 601 BHN, 2.65 mm to 2.5 mm penetration and 2.41 kg and 3.00 kg concentricity mass has been established. It could be recommended that, the result could be used to improve the general performance of the foundries while the redesigned version could be recommended for adaptation.

Source: KNUST
An Investigative Study of Project Management Practices in the Electricity Company of Ghana Accra, West Region

The processes of initiation, planning, execution, monitoring and controlling and closing are the standards used to ensure the effective implementation of all projects. However, most organisations undertake projects without necessarily adhering to these standard project management practices leading to the failure of most projects. The Electricity Company of Ghana (E.C.G.) is the sole power distributing company in six out of ten regions in Ghana. It carries its mandate through a number of projects aimed at building substations and distribution networks. The purpose of this study was to investigate the extent to which project management processes are adopted in the implementation of projects in the Accra West Region of ECG. It was also to investigate the success rate of projects undertaken by the region and find out the causes of project failure in the company. The method used to carry out this research was solicitation of information from the engineers and managers who supervise projects through questionnaires. Data gathered was analysed using the Statistical Package for Social Science (SPSS). The major findings of the research indicated that the project management processes of initiation, planning, execution, monitoring and controlling and closing were adopted in the implementation of projects in the Accra West Region of ECG. It was highly recommended that management of ECG ensures that its regions implement projects using the standard processes to the letter for a high success rate of its projects.

Source: KNUST