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- ItemAssessment of microbiological and physicochemical quality of wastewater used for vegetable irrigation along the old waterworks stream in Tamale metropolis of Ghana(KNUST, 2018-06) Bashiru Nuhu, RabiWorldwide, several million hectares of farmland in estimated 50 countries are used to cultivate agricultural produce by farmers who have adopted the application of untreated and or partially treated wastewater from various sources. The application of untreated wastewater which are contaminated with microbes and chemicals including heavy metals poses serious public health threat on the vegetable farmers, vendors and consumers of vegetables cultivated using such untreated wastewater. This study assessed the microbiological, physical and chemical qualities of wastewater used for vegetable irrigation along the Tamale old waterworks stream in the Tamale Metropolis of Ghana. Two wastewater samples each were collected from the four sampling sites: Waterworks upstream (WWU), Gumbihini midstream (GMS), Nyanshagu midstream Gardens (NMS) and Tunayili Kulbong Downstream Gradens (TKDS) along the stream monthly for six consecutive months for microbial and physicochemical parameters for dry and rainy seasons. A total of forty-eight water samples were collected and analysed for their microbiological, chemical and physical qualities using standard protocols adopted by the American Public Health Association (APHA, 1998). The results obtained showed consistent increase in the bacterial and physicochemical load for both irrigation seasons. The bacterial parameters studied include total coliform, faecal coliform, E. coli, Staphylococci, Enterococci, Pseudomonas and total heterotrophic bacteria. The statistical analysis on the microbials gave a weak correlation (r=0.24) among the individual sampling sites for microbial statistics. More so, there is a significant difference between the wastewater samples for dry and rainy season irrigation of microbial parameters with (p = 0.005) from the pairwise sample test. Results obtained showed consistent increase in the bacteria load for both seasons with the rainy season recording higher loads than the dry season except for total heterotrophic bacteria which was rather higher in the dry season as compared to rainy season. Overall, bacterial count recorded was lowest at GMS1 and highest at NMS2 for both seasons. The physicochemical parameters include, pH, conductivity, total alkalinity, total hardness, calcium hardness, magnesium hardness, carbonate hardness, bicarbonate hardness, calcium, magnesium, chloride, fluoride, sulphate, sulphide, phosphate, ammonia-nitrogen, nitrate-nitrogen, nitrite-nitrogen, aluminium, total iron, manganese, copper, zinc, cyanide, total chromium and potassium. There is strong correlation (r=0.99) among the individual sampling sites for physicochemical parameter analysis of wastewater samples during dry and rainy season irrigation schemes. More so, pairwise analysis indicates that there is no significant difference (p= 0.41) among the sampling sites for physicochemical wastewater samples for dry and rainy season irrigation of physicochemical parameters. Overall, physicochemical values recorded were lowest at GMS1 and highest at NMS2 for both the dry and rainy season samples. More so, bacterial counts recorded for all the microbial parameters exceeded the WHO (2006b) guideline of 1x103cfu/100ml for unrestricted irrigation of crops likely to be eaten raw whilst the physicochemical parameters determined were found to be within FAO/WHO guidelines for irrigation water except for colour, total alkalinity, chloride, zinc and cyanide. Most of the chemicals had levels above WHO guidelines and are potential health threat especially high nitrate concentration in irrigation water causes blue baby syndrome. The application of untreated wastewater poses serious public health threat on the vegetable farmers, vendors and consumers of vegetables cultivated using such untreated wastewater. It is therefore recommended that wastewater for irrigation of ready-to-eat vegetables be treated using biological nutrient removal system and wastewater stabilisation ponds to reduce and or eliminate contaminants before irrigating vegetables.
- ItemThe scalability metric, based on cost-effectiveness in distributed systems using fundamental laws(KNUST, 2018) Gyasi Emmanuel KwabenaTodayโs computer systems are more complex, more rapidly evolving, and more essential to the conduct of business than those of recent past. The complexity becomes more rigid in the case of distributed systems. A distributed system is a collection of independent computers that appear to its users as a single coherent system. A distributed system should be deployable in a wide range of scales, in terms of numbers of users and services, quantities of data stored and manipulated, rates of processing, numbers of nodes, geographical coverage, and sizes of networks and storage devices. The derived scalability metric of this thesis is based on cost effectiveness, in which the effectiveness is a function of the system's throughput and its Quality of Service. It is a strategy based scalability metric that generalizes the well -known metrics for scalability of parallel computations to describe heterogeneous distributed systems. Scalability is measured by the range of scale factors that gives a satisfactory value of the metric, since a good scalability is a joint property of the initial design and the scaling strategy. What makes this derived metric unique is the fact that, it separates the impact of throughput and response time on the metric, formalizing the notation of a scaling strategy, introducing QoS evaluation and more also, introducing formal scalability enablers which are optimized at each scale factor. Throughput curves for all systems with bottleneck demand ๐ท๐๐๐ฅ are constrained to lie below the line 1๐ท๐๐๐ฅโ. If one needs to improve the performance further than this limit, then it is necessary to reduce the demand at the bottleneck center somehow.
- ItemPricing critical illness insurance using the dash and grimshaw model(KNUST, 2018-06) Asabre, EbenezerCritical Illness Insurance is a new product and its now gaining grounds on the Ghanaian insurance industry market. This research is aimed at developing a fair pricing system for a critical illness insurance using the Dash and Grimshaw model which has embedded multi-state(decrement) model. Due to the uncertainty in the future and the possibility of an individual being diagnosed of some critical illness, it is important to cover oneself against this possible adverse financial trauma. This research considered five critical illnesses thus cancer, heart attack, stroke, kidney failure and Coronary Artery Bypass Graft. Data on the incidence rates for all the critical illnesses was used to compute the stand alone rates, acceleration rider benefit rates and premium rate from ages 20 to 80 inclusive using the Dash and Grimshaw model. Results from my computations showed that incidence rates and its corresponding premium rates are directly proportional to oneโs age. Also the difference in stand-alone and accelerated rates was directly proportional to oneโs age.
- ItemDilemmas in model selection in time series analysis(KNUST, 2018-06) Arthur, DorisThis study seeks to resolve two important dilemmas in model selection in time series analysis. These are to compare the performance of the graphical and the information criterion methods in selecting the true model. In addition, Yu et al. (2005) relative precision performance stability was modi_ed. For the graphical and information criterion comparison, dataset from ARIMA models were simulated. Also the cocoa production and rainfall datasets in Ghana were used to validate the modified relative precision performance stability of Yu et al. (2005). It was observed from the study that, in comparison to the performance of the graphical method and the Akaike information criterion (AIC) in selecting the ARIMA models, the information criterion performs better than the graphical method. Also, in verifying for the size of the evaluation sets in forecasting, whether to select a single model or combine the models of di_erent models, our findings showed that the size of the evaluation sets may not influence the decision of selecting or combining since 97% of the decisions were to combine the models. In addition to that, though there was a modification on the computations of the relative prediction performance stability formerly utilized by [Yu et al., 2005], the decision rule still remains the same. Hence, whether the use of the mean or median on different the size of evaluation sets and interval, the combining strategy still outperforms.
- ItemAnalysis of metal content of seized cocaine in Ghana(KNUST, 2018-11) Bentil, EdwardThe trafficking of cocaine has become a global challenge now and Ghana is no exception. Cocaine is a whitish powder, which is, produced both from natural and synthetic means. The aim of the project was to study the metal content of seized cocaine in Ghana and the data used for batch identification. Ten metals namely Pb, Cu, Mg, Mn, Cr, As, Ni, Fe, Co and Ca were analyzed in 37 cocaine samples which were sampled from seizures made from 2010 to 2014 and samples selected based on within-seizure and between-seizure classifications. Seized cocaine samples were obtained from Ghana Standards Authority by the help of Narcotic Control Board of Ghana. All seized illicit cocaine samples used were classified under natural cocaine. Analyses of the metals were done using ICP-MS and data analysis done using ANOVA at 95% confidence level. The results showed that, Calcium recorded the highest amount in all the samples with a mean ppm value of 64.94ยฑ54.60 with Magnesium, Zinc and Iron recording moderate amounts. All the samples analyzed contained Calcium since lime is known to be used as one of the additives in the production of cocaine. All the cocaine samples, which were sampled, based on within-seizure classification under class A showed no significant differences between each pair. With three sample pairs under class B in the within-seizure classification, one of the pairs, 103A and 105B showed no significant differences between them even though they were sampled from two different packages from the same seizure. Five samples from five different seizures also showed significant difference among them showing that they came from different batches or origin. It could be confirmed that seized cocaine contained some poisonous heavy metals like Lead, Arsenic and Chromium, which had amount that could affect the user. Based on the data gathered from the within-seizure class A group, it could be proposed that a missing cocaine could be identified by its metal content if no adulterants were added during the time it could not be found. With the information on the metal content of cocaine, the identity of seized cocaine can be achieved with the purity during forensic screening in order to protect the cocaine during investigations.