In the present paper we investigate flame spread in laminar mixing layers both experimentally and numerically. First, a burner has been designed and built such that stationary triple flames can be stabilised in a coflowing stream with well defined linear concentration gradients and well defined uniform flow velocity at the inlet to the combustion chamber. The burner itself as well as first experimental results obtained with it are presented. Second, a theoretical model is formulated for analysis of triple flames in a strained mixing layer generated by directing a fuel stream and an oxidizer stream towards each other. Here attention is focused on the stagnation region where by means of a similarity formulation the three-dimensional flow can be described by only two spatial coordinates. To solve the governing equations for the limiting case in which a thermal-diffusional model results, a numerical solution procedure based on self-adaptive mesh refinement is developed. For the thermal-diffusional model, the structure of the triple flame and its propagation velocity are obtained by solving numerically the governing similarity equations for a wide range of strain rates.

Nanotechnology-based agrochemical delivery systems would ensure efficient and economical utilization of these very important agricultural inputs. In this study, mesoporous silica nanoparticles with particle diameters of -150 nm and pore sizes of -2.5 nm were synthesized via liquid crystal templating mechanism. Urea, as a model agrochemical molecule, was entrapped in the mesopores of the siliceous material by simple immersion loading using aqueous urea solutions. About 15.5% (w/w) of urea was loaded inside the pores mainly by physisorption while the total adsorption capacity of mesoporous silica nanoparticles could reach up to 80% (w/w). Highly concentrated urea solution was found to be more effective due to high driving concentration gradient generated. Release process of the urea-loaded mesoporous silica nanoparticles in water and soil indicated a two stage sustained slow release-profile. The findings for soil release studies revealed at least fivefold improvement in the release period. By the ability to entrap urea guest molecules into its mesopores and release them in a controlled manner, mesoporous silica nanoparticles demonstrated its great potential as a nanocarrier for agrochemicals.

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Physical and thermal properties of briquettes produced by recycling charcoal dust under different processing conditions have been reported in this study. The main aim was to investigate the effects of the binder and processing conditions on the properties of briquettes. The effect of adding molasses binder on combustion properties of the briquette was first assessed. Then by fitting experimental data, mathematical models to predict gross calorific value, ash content, moisture content, relaxed density and shatter index with respect to binder mass fraction, drying temperature and compaction pressure were developed. All briquettes properties were predominantly affected by amount of molasses used. Molasses mass fraction increment in briquette results in significant increment in ash content, moisture content, relaxed density and shatter index and significant reduction in gross calorific value. Drying temperature did not have major influence on briquette properties except moisture content. Compaction pressure (50-150 MPa) used in this study had negligible influences on all briquette properties. Therefore, such high pressure which involves energy consumption is not necessary during production of charcoal dust briquettes. Optimized values of gross calorific value and shatter index were 29.031 MJ/kg and 80.363%, respectively, for 50 MPa compaction pressure, 29.512 °C drying temperature and 10% molasses mass ratio.

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