Tag Archives: Modeling

Mathematical Assessment of the Transmission Dynamics of HIV/AIDS with Treatment Effects (Published)

This article examines the transmission dynamics of HIV/AIDS with treatment effects. The total population ( ) was grouped into four compartments namely susceptible individuals at time t   ( ), infected humans at time t ( ), individuals on treatment at time t ( ), and the AIDS carriers at time t  ). A first order deterministic mathematical model for the case is formulated and analyzed to gain insight into the qualitative features of the local stability and disease free equilibrium which enable us to understand the  transmission dynamics of the disease. The numerical simulation of the model was carried out to investigate the sensitivity of some threshold parameters on spread rate of the disease. We also investigated  the impact of early detection of HIV cases and compliant behavior of patients on treatment. Our  results from numerical simulation and early detection of HIV case/ compliant behavior of patients on treatment show that early detection of HIV case and compliant behavior of patients on treatment reduce spread of the disease and minimize rate at which people develop AIDS.

Keywords: HIV/AIDS, Modeling, Transmission dynamics, Treatment., mathematical assessment


HEC-RAS (Hydrologic Engineering Center’s River Analysis software) is a one-dimensional computer program that models the hydraulics of water flow through natural rivers and other channels [1]. It was used to modify the existing culverts on River Omi which in the past years and of recent has inundated its surroundings. The hydrological data was also measured and used as an input to the model. The model was used over MIKE11, flovial and other hydraulic mathematical model because of its high visual capability and complete output with detailed [2].
The results showed and confirmed that the existing culverts at the considered cross-sections could no longer accommodate the river’s discharge. A box-culvert spanning 7.2m with a rise of 1.8m will be adequate and economical to replace the existing ones. The existing wing wall was sufficient for the modified cross-section.

Keywords: Culverts, Flood, HEC-RAS, Modeling, River Omi


Solar desalination is considered as one of the promising renewable energy-powered technology for producing fresh water. The Seawater greenhouse (SWGH) system uses the solar desalination principle and works by saturating the air with moisture vaporizing from saline water inside a greenhouse and later dehumidifying, thus, causing freshwater condensation. The SWGH is a unique concept which combines natural processes, simple construction techniques to provide a low-cost solution to one of the world’s greatest needs-fresh water. It is a method of cultivation that provides desalination, cooling and humidification in an integrated system. Self-sufficiency in water production combined with low internal irrigation requirements mean that the SWGH offers significant water saving by reducing agricultural demand on main and groundwater. Its purpose is to provide a sustainable means of agriculture in arid coastal areas where the scarcity of freshwater and expense of desalination threaten the viability of agriculture.

Keywords: Analysis, Modeling, Solar Energy, arid communities, desalination, plantation


A detailed analysis of the indices of organizational and marketing innovations has been examined in this study. The specific objectives duly analyzed were identification of the features of small scale flour marketing firms; analysis of the profitability and efficiency of the firms using income statement; ascertaining the determinants and indices of organizational, marketing and technological innovations. The technique of data collection was firstly a purposive sampling method to choose Aba and Umuahia Metropolis and small scale flour marketing firms and; secondly a random sampling selection technique was employed in selecting fifty specific firms for the study. The data elicited from sampling of fifty small scale flour marketing firms were analysed via descriptive statistics, income statement, probit and Ordinary Least Square Multiple regression analyses. The report from the results analyses showed that the significant indices of marketing innovation were price strategy, promotion strategy, distribution method, sales method, packaging and production strategies. On the other hand, significant indices of organizational innovation included work arrangement, quality management, motivation, use of promotion, product modification and employee schedule. The organizational innovation was highly significant than marketing innovation of small scale flour marketing firms in contributing towards enhancing the performance of small scale flour marketing firms. Thus, the organizational and marketing innovation indices analyzed in this work remained very significant and highly important tools for profitable marketing activity and in unlocking the marketing potentials of the firms and in encouraging competitive advantage over other firms that were indifferent about the strength of these organizational and marketing innovations. The study indicated that any small scale flour marketing firm that adopted for proper marketing and organizational innovations adapted successfully to emerging marketing challenges. Thus, it is recommended that small scale flour marketing firms should properly engage in organizational innovation involving work arrangement and effective employee work schedule which will contributing efficiently to better firm performance. Further, it is recommended that small scale flour marketing firms should include in their innovation portfolios price strategy, promotion strategy, distribution method, sales method, packaging, motivation, work arrangement, and product modification respectively which have the potentials to sustain the performance of the firms extensively.

Keywords: Determinants, Firm, Flour, Innovations, Marketing, Modeling, Organizational

Modeling Performance Characteristics of a Turbojet Engine (Published)

This work is an approach to analyze the performance of jet engine with an alternative flow control mechanism. The work analyzes the feasibility of a thrust control mechanism by regulating the flow at the engine inlet to increase the engine rpm for the same value. This approach adds value to the design process with the aim of increasing performance levels in the engine operation. The work is focused on performance charactristics of turbojet with reduced inlet pressure to the compressor engine. A real-time turbojet engine integrating aerothermodynamics of engine components, was developed, together with principles of jet propulsion and inter component volume dynamics represented in 1-D non-linear equations. Software program Simulink, a commercially available model based graphical block diagramming tool from MathWorks was used for dynamic modeling of the engine. The result shows that with increase in shaft rpm, pressure and temperature ratio values across the compressor-turbine assembly increases. Performance parameters of the engine are analyzed with the increase in compressor pressure ratio and shaft rpm.

Keywords: Modeling, Propulsive Efficiency, Specific Fuel Consumption, Specific Thrust, Thermal Efficiency, Turbojet