The 41st volume of International Journal of Engineering Research in Africa contains articles describing the research results in the fields of materials science, mechanical engineering, control, wireless sensor networks, construction materials and technologies, technological processes and materials in the chemical production, freight transportation and structural analysis of production systems. The articles will be useful for many engineers as well as for academic teachers and students majoring in these fields of engineering science.

The 69th volume of the journal includes articles dedicated to the latest research results in properties and processing technologies of structural materials such as steel, polymers, and composites, analysis and design of sliding mode controllers and automation of centrifugal pumps, designing of geothermal heat exchangers, investigation of seismic behaviour of soil-based structure and analysis mechanics of river's sediments transfer in conditions of Wadi Skhirate, Morocco. The issue will be useful to specialists in mechanical engineering and construction.

Present volume of "International Journal of Engineering Research in Africa" contains of peer-reviewed papers based on results of research and engineering solutions in different areas of technical science including modern communication and information technology. And we also continue a series of the special publications which are devoted to Modeling of Heat and Mass Transfer in Different Fluid Flows.

This periodical edition includes peer-reviewed papers based on results of scientific research and engineering solutions in different areas of modern engineering science.

This journal's issue includes articles that describe the latest research results in alloy metallurgy, building materials and construction technologies including building seismic provision and results of analytical modelling of mechanical properties of shrink-fitted thick-walled cylinders and nose landing gear for Boeing 777. There is also analysed a hybrid system solar chimney-air soil heat exchanger for natural ventilation and modified particle swarm optimisation for maximum power point tracking for solar photovoltaic systems and presented mathematical modelling of agricultural insurance pricing in Morocco. This volume will be helpful to many engineers in machinery, manufacturing, energy industry and construction.

Lean Manufacturing is defined as efficient approach to identifying and eliminating waste (non–value add activities) through regular improvement flowing the product in the pull of the customer in reach of perfection. Lean manufacturing is often simply "lean", is a systematical method for the leave out of waste ("Muda") within a manufacturing system. Lean also takes into account waste created through overwhelm ("Muri") and waste created through imperfection in workloads ("Mura"). Working from the angle of the client who consumes a product, "value" is any action or process that a customer want to pay for. “ To solve the problem of waste, Lean Manufacturing has number of tools at its disposal. These include continuous process improvement the ‘5 Ways’ and mistake-proofing. Thus it can be seen as taking a very similar approach to other improvement procedure.”