Modelling the influence of age structure on the forest biomass availability: a case study of Karbala forest, Western Mbadjini region of Comoros

In this work, a deterministic mathematical model for the Influence of human age structure on forest biomass availability, incorporating public enlightenment campaign parameter was developed and analyzed. The model consists of three autonomous differential equations for the forest biomass, Junior and Adult populations. The Zero, Junior and Adult free as well as the interior equilibrium states of the model were obtained and analyzed for stability. Numerical simulation of the various model parameters were obtained using mat lab software. The simulation gave the public enlightenment coverage level that would guarantee high forest biomass density and thus optimum yield.Keywords: Forest, biomass, Density, Stability, Equilibriu

Frequency Dependent Incidence Model for Acute and Chronic Schistosomiasis

In this research work, a deterministic mathematical model for schistosomiasis transmission dynamics is presented. The model consists of five non-liniar ordinary differential equations incorporating the acute and chronic infectious compartments. The basic reproductive number, (the number of secondary infections when a single infectious individual is introduced into a population where everyone is susceptible) was obtained. Furthermore, we gained and analyzed for stability, the disease-free and endemic equilibrium. The qualitative feature of the model shows that the long-term behavior of the model is independent of initial conditions. Numerical simulation of the various state variables were obtained using matlab software

A review of weldability of carbon steel in arc-based welding processes

The weldability of carbon steel is determined by carbon equivalent (CE) for predicting/estimating preheat temperatures necessary for weld integrity of the weldment. The microstructure of the welded carbon steel at the heat affected zone (HAZ) plays an essential role in the mechanical properties of the weldment, thus, painstakingly selecting welding process and parameters to slowdown the cooling rate are ensued by sound weld quality and crack free weld (enhanced service performance). This research work reviews the effects of various welding processes and parameters on microstructure and mechanical properties of carbon steels in arc-based welding