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This paper investigated the effects of laboratory synthesised rocket composite propellants’ formulations on propellant performance parameters using response surface methodology (RSM). For the sake of a safe environment, the propellant is made of chemical constituents that have less severe effects on air quality. Experimental measurements of propellant performance parameters were carried out using the ballistic evaluation method. The thrust generated during combustion, the burn time and the propellant combustion temperature were measured using a data acquisition facility equipped with a button load cell and a thermocouple. Specific impulse, density, temperature, characteristic velocity, molecular weight and heat ratio were computed from the measured parameters. The resulting optimum rocket composite propellant formulations were 65.1%, 18.1%, 9.1%, 3.6%, 2.2% and 1.9% for the oxidiser, binder, fuel, opacifier, burning rate enhancer and catalysts, respectively. The corresponding performance indices i...

The efficiency of oil palm calyxes (OPC) in removing heavy metals from aqueous solution is presented in this report. Qualitative analyses showed the participation of hydroxyl, carboxylate and methoxyl groups in the binding process. OPC surface was observed to be amorphous, highly ordered and multilayered. Quantitative analyses indicated that the removal of Cd2+, Pb2+ and Ni2+ occurred at fast kinetics, with uptake of 38.24, 47.66 and 32.61 mg/g respectively, after 5 min. Optimum Cr3+ adsorption was however not reached after 3 h, indicating slow kinetics. Pseudo-second-order model best described the kinetics of the adsorption, suggesting chemisorption as the rate-limiting step. Metal uptake increased with rise in adsorbate concentration. However, no further rise in uptake was observed with increase in Pb2+ concentration beyond 200 mg/L. Data from the sorption of Cd2+, Ni2+ and Cr3+ were best described by Freundlich isotherm, while those of Pb2+ obeyed Langmuir isotherm, with maximum adsorption capacity (qmax) of 120.48 mg/g. Thermodynamic studies indicated that the removal of Cd2+, Ni2+ and Cr3+ was exothermic and occurred with decreased disorderliness, while Pb2+ removal was endothermic with increased entropy. The negative values of ΔG° indicated the spontaneity of the biosorption of Cd2+, Pb2+, Ni2+ and Cr3+ onto OPC.

The current electricity shortage from Nigeria’s national grid and the scarcity of refined petroleum products including kerosene which is used for domestic purposes make the use of fuelwoods more dominant in the country; especially in the rural areas. Air emissions from open burning of pre-determined quantity of some common fuelwoods identified in regions were characterized for gaseous air pollutants using the E8500 combustion analyzer. The measured concentrations were used to calculate emission factors of the air pollutants. The emission factors for the gaseous emission from the fuelwoods were 181.84–6547.57 g/kg for CO, 44.07–2986.40 g/kg for HC, 2.24–267.36 g/kg for NOx while SO2 had 0.0–9.87 g/kg. This study establishes that Gliricidia sepium had the minimum emission factor for all the considered gaseous pollutants except for SO2, thus all stakeholders considering the adoption of fuelwood in the country’s quest for increased energy mix can be properly guided on the pollutants associated with th...

The evaporative emissions from multicomponent fuel are expected to change significantly with the progress of evaporation. This study presents the findings of air emission associated with changes (increase) in evaporation process of gasoline. The parameters measured in the experiment included the weight loss, density, viscosity of gasoline, and the evaporation rate. Results showed that the parameters changed significantly as evaporation progressed. The weight loss was from 3.02% to 5.45% after 30 m and presented a logarithmic curve with time. The density measurements of the gasoline samples were 728.5–746.7 kg/m3. The evaporation rate which was 1.22 × 10−5–2.14 × 10−5 kg/s showed great increase with decrease in density and kinematic viscosity at ambient temperature with sample C (from Lagos) having the highest evaporation rate. The emission rate was observed to be inversely proportional to the sample density. Most of the changes might be attributed to the air emission of volatile hydrocarbons such ...

Power sector in Nigeria is undergoing structural reforms aimed at improving and expanding the current generation capacity, using thermal power plants. Ground level concentrations of air pollutants emitted from natural gas-powered thermal power plants were estimated using the American Meteorological Society-Environmental Protection Agency Regulatory Model (AERMOD). The average 24-h ground level concentrations of CO, NOx, SO2, particulate matter (PM), and volatile organic compounds (VOCs) were 31.88–72.79; 61.33–104; 0.61–3.91; 0.21–1.52; and 0.19–1.09 µg/m3, respectively. There is need for continuous monitoring of ground level concentration of pollutants around the thermal power plants to guarantee the safety of the environment in the host communities.