An Efficient Seven-Step Block Method for Numerical Solution of SIR and Growth Model

In this article, a new implicit continuous block method is developed using the interpolation and collocation techniques via Power series as the basis function. A constant step length within a seven-step interval of integration was adopted. The selected grid points were evaluated to get a continuous linear multistep method. The evaluation of the continuous method at the non-interpolation points produces the discrete schemes which form the block. The basic properties of the block method were investigated and found to be consistent, zero stable and hence convergent. The new method was tested on real life problems namely: SIR and Growth model. The results were found to compare favourably with the existing methods in terms of accuracy and efficiency.  Keywords: Block method, Growth Model, implicit, power series and SIR model

Determination of an Annual Groundwater Recharge and Demand in Oke-Ero LGA, Kwara State, Nigeria

Efficient groundwater management, water consumption rate and quantitative determination of the amount of rainfall that recharges groundwater naturally is essential for a place like Oke-Ero LGA where  the people in Oke-Ero depend mainly on groundwater as the only source of water supply. In this work, an attempt has been made to evaluate the amount of rainfall that recharges aquifers using Krishna model with a view to knowing the groundwater potential of the area and determine the water consumption rate. This study established that Oke-Ero LGA has 65.7 million cubic meters (MCM) groundwater potential annually, from the survey output the average daily water demand in Oke-Ero is 75 l/c/d. The total water demands across the LGA based on 2016 population estimate is 2.11 MCM/year with anticipated increase of 4.34 MCM/year by 2040 and expected water demand increase rate of 3.2% annually. This work has ascertained that the available water is sufficient to take care of the water demand of the people in Oke-Ero LGA and it also shows that there is more water for other activities such as industrial purposes. Keywords - Groundwater potential, Groundwater recharge, Oke-Ero LGA, Water demand.

Some Thermodynamic Properties of White Yam (Dioscorea rotundata) Slices Dehydrated in a Refractance WindowTM Dryer

The objective of this study is to estimate the changes in Enthalpy, Entropy and Gibbs Free Energy of yam slices dehydrated at different temperatures using a Refractance WindowTM dryer. Dehydration of 1.5, 3.0 and 4.5 mm thick yam slices, was performed with water temperatures of 65, 75, 85 and 95oC in the flume of a Refractance WindowTM dryer. During the dehydration operations, the moisture-content history data were recorded. For the process conditions considered, the moisture content history data was used to calculate the moisture diffusivity and the activation energy of dehydration of the samples. Subsequently, changes in Enthalpy, , Entropy, , and Gibbs Free Energy, ), were calculated. For the process conditions studied, the changes in, , , and, varied from 20,381.33 to 25,217.05 J.mol-1., -140.69 to -122.29 J.mol-1.K-1.and 67,934.80 to 70,220.15 J.mol-1, respectively. This study is essential as knowledge of these thermodynamic parameters are useful for the optimal design and sizing of preservation dryers for argo-products. Keywords— Enthalpy; Entropy; Gibbs Free Energy; Refractance WindowTM Dryer; Yam

Fuel Characterization of Agro-wastes and Briquettes Produced from Rice Husk, Groundnut Shell and Corncob Blends

The choice of agro waste for the production of briquettes for domestic and industrial cottage utilization depends on the residues’ physical and fuel characteristics. This study investigate the physical and fuel characteristics for both the residues and blends of rice hull, groundnut shell and corncob. The residues were subjected to size reduction process and variance analysis was used to establish the influence of each sample blends.  Different samples of briquettes were produced by blending rice hull (R), groundnut shell (G) and corncob(C) with different ratios of R:G:C respectively using cassava starch as a binder. The residue’ dimensions and densifications of the sample briquettes were determined using standard methods.The results revealed the following ranges of values; For the compressed residues, density (0.075 - 0.099Kg/m3), volume (0.001 - 0.002m3), height (1.0357 - 1.0343m). For the relaxed residues, density (0.049 - 0.210Kg/m3), volume (0.0001 -0.0002m3), height (1.0357 - 1.0343m). The residual density of rice hull, groundnut shell and corncob are 104, 105, and 103 (Kg/m3) respectively. The densification; compressed density (461.22 - 627.24 Kg/m3), relaxed density (285.47 - 393.63 Kg/m3), density ratio (0.56 - 0.66), relaxation ratio (1.52 - 1.79), and compaction ratio (1.46 to 2.01). Blend formulations affected the combustion characteristics of the briquettes, with low moisture briquettes possessing higher calorific values. The briquette formulation containing ratio 50:20:30 of rice hull: groundnut shell: corncob respectively had more positive attributes of biomass fuel such as lower relaxation ratio and high compaction ratio than the control and other formulated briquettes in this study. Generally, significant (p<0.05) differences existed between the samples in almost all the parameters.Keywords: Briquettes, Corn comb, Densification, Fuel Characterization, Groundnut shell, Rice hull

Determination of Aquifer Characteristics in Okija, Anambra State, Nigeria

Knowledge of hydraulic properties of groundwater aids economic and environmentally friendly exploitation of water resources in water-scare rural area such as Okija. In this study therefore, the aquifer constants are evaluated for Okija town in Ihiala Local Government Area of Anambra State, Nigeria to facilitate efficient and effective exploitation of the water resources in the area. The drawdown test involved pumping down the water level and monitoring the response of hydraulic head in the surrounding aquifer. The computation of formation constants is performed in three ways: Theis method, Cooper-Jacob method and Chow method. Model Selection Criterion (MSC was used to evaluate the discharge predictions from the three methods. The results show that transmissivity and storage coefficient for Theis method are 256. 37 m2/day and 146.67 m2/day; Cooper-Jacob method are 251.71 m2/day and 131 m2/day, and chow method are 2 67.87 m2/day and 146.67 m2/day respectively. This work represents a practical and novel approach to the determination of a key hydrogeological parameter for a highly transmissive aquifer. Keywords—.Aquifer constants, Theis method, Cooper-Jacob method, Chow method, Okij

A Knowledge Representation Model Based on Select and Test Algorithm for Diagnosing Breast Cancer

There exist several terminal diseases whose fatality rate escalates with time of which breast cancer is a frontline disease among such. Computer aided systems have also been well researched through the use intelligent algorithms capable of detecting, diagnosing, and proffering treatment for breast cancer.  While good research breakthrough has been attained in terms of algorithmic solution towards diagnosis of breast cancer, however, not much has been done to sufficiently model knowledge frameworks for diagnostic algorithms that are knowledge-based. While Select and Test (ST) algorithm have proven relevant for implementing diagnostic systems, through support for reasoning, however the knowledge representation pattern that enables inference of missing or ambiguous data still limits the effectiveness of ST algorithm. This paper therefore proposes a knowledge representation model to systematically model knowledge to aid the performance of ST algorithm. Our proposal is specifically targeted at developing systematic knowledge representation for breast cancer. The approach uses the ontology web language (OWL) to implement the design of the knowledge model proposed.   This study aims at carefully crafting a knowledge model whose implementation seamlessly work with ST algorithm. Furthermore, this study adapted the proposed model into an implementation of ST algorithm an obtained an improved performance compared to the simple knowledge model proposed by the author of ST algorithm. Our knowledge mode resulted in an accuracy gain of 23.5% and obtained and AUC of (0.49, 1.0). This proposed model has therefore shown that combining an inference-oriented knowledge model with an inference-oriented reasoning algorithm improves the performance of computer aided diagnostic (CADx) systems. In future, we intend to enhance the proposed model to support rules. Keywords— Semantic web, ontology, OWL, breast cancer, Select and Test (ST) algorithm, knowledge representatio

Development of an Instrumentation System for a Laboratory Model Food Product Dryer

To achieve optimal dryer performance, the process parameters required for both the optimization and control of the drying process must be made available via the instrumentation system. A few works have been reported on the development of instrumentation systems for handling drying system parameters. Out of which, some are deficient in the number of drying process parameters that can be handled, while others are unreliable and inaccurate. Therefore, there is the need to develop a microcontroller-based instrumentation system that can monitor, measure, control, display and store the main drying process parameters and sample weight with a high degree of reliability and accuracy. In this study, the sensors were selected based on system specifications and interfaced with the microcontroller. The codes for controlling, logging and displaying of drying parameters were developed and installed on the microcontroller. When tested at steady-state conditions, the system yielded satisfactory results with maximum control and detection errors being 2.0% and 1.8% for the temperature and sample weight, respectively. The developed system can be used for efficient computation of both the dry and wet basis sample moisture content values and also detect the set sample weight. Keywords— Dryer, Drying parameters, Instrumentation system, Moisture content, Sensor

Effect of Process Parameters on the Surface Roughness and Kerf Width of Mild Steel during Plasma Arc Cutting Using Response Surface Methodology

This study investigated the effects of process parameters of plasma arc cutting (PAC) of low carbon steel material using analysis of variance. Three process parameters, cutting speed, cutting current and gas pressure were considered and experiments were conducted based on response surface methodology (RSM) via the box-Behnken approach. Process responses viz. surface roughness (Ra) and kerf width of cut surface were measured for each experimental run. Analysis of Variance (ANOVA) was performed to get the contribution of process parameters on responses. Cutting current has the most significant effect of 33.43% on the surface roughness and gas pressure has the most significant effect on  kerf width of  41.99% . For minimum surface roughness and minimum kerf width, process parameters were optimized using the RSM. Keywords: Cutting speed, cutting current, gas pressure,   surface roughness, kerf widt

A Framework for Sustainable Maintenance of Offshore Energy Structures

This paper proposes a structure for maintenance decision support suitable for application to renewable energy assets. The method combines subjective tacit knowledge of subject-area experts with well-structured Analytical Hierarchical Process (AHP) to elicit weights of criteria relevant for effects evaluation of possible failures modes towards support for component’s maintenance decisions. The Technique for Ordered Preference using Similarity to Ideal Solution (TOPSIS) algorithm is adopted for aggregating the evaluation scores and achieving priority indexing given the conflicting characteristics of some criteria. Part of the highlights of the Framework is the implementation of the group experts, as well as individual expert's elicitations in a complimentary manner that eliminates subjective opinions and achieves a repeatable evaluation score. The conclusion of the analysis is the prioritisation of the component’s failure; An indicative case study of offshore wind turbine jacket support structure is used to demonstrate the applicability of the approach and the analysis results-which shows priority failure modes for focused maintenance intervention as bending of Chord/Brace ( ), collapse of Chord/Brace ( ), buckling of Long piles ( ), and Truss( ), overturning of Skirt pile ( ), and fatigue of Long pile ( ), further demonstrates the capacity of the model to support maintenance decisions. Caution is exercised in the selection of criteria that would capture the objectives of the risk analyses by consulting wide range of industry experts. Keywords— AHP, Expert, Offshore energy, TOPSIS, Wind turbine Support Structur

Evaluation of the Hydraulic Conductivity of Compacted Laterite-Metakaolin Mixtures for Solid Waste Leachate Containment

This paper presents the results of a study conducted to investigate the benefits of using metakaolin (MK) with laterite as liner material for containment of municipal solid waste (MSW). Laboratory tests were conducted on laterite specimens treated with MK at concentrations of 0 - 20 % by weight of the soil and compacted using four types of compaction energies. Hydraulic conductivity was determined based on permeation of the compacted laterite - MK mixtures with deionized water (DW) and municipal solid waste leachate (MSWL), respectively. Deionized water was the reference permeant fluid.  The results showed that hydraulic conductivity generally decreased with increase in the percentage addition of MK to the soil. From an economic and sustainability point of view, it has been found from the results that 5 % MK can be added to soil and compacted at moulding water content of 14.1 % using the West African Standard (WAS) compaction energy to achieve the regulatory hydraulic conductivity of less than or equal to 1 x 10-9 m/s for compacted soil liner. The natural logarithm of the hydraulic conductivity experimental results were computed and used to develop regression equations for estimating hydraulic conductivity given MK contents and compaction energies. The results of the two-way analysis of variance (ANOVA) test carried out at 5 % level of significance showed that calculated F-statistics are statistically significant and the measured values of hydraulic conductivity compare well with the predicted values. The developed models can therefore be used to give good estimates of hydraulic conductivity of soils having similar properties with the laterite investigated in this study. Therefore, the developed models can be used to give good estimates of hydraulic conductivity of soils having similar properties with the laterite investigated in this study. Keywords ­_ Deionized water, Hydraulic conductivity, Leachate, Metakaolin, Municipal solid waste