Soils are the basic and most important resources of any people. Differences in soil's physical and chemical properties are related to the spatial distribution of land uses. Most of these human activities generate toxic substances that are transported considerable distances away from source and become accumulated in soils, sediment, water bodies and fisheries. Urban soils are largely affected by impact of urbanization whose consumptive pattern is related to the social and economic aspect of the society. The study deployed contaminant factor (CF) and geo-accumulation index (Igeo) to examine the differences in the urban soils of Lagos Mainland Area due to human activities. The topsoils of the predominant human activities identified in the area were sampled and analyzed to find out the differences in the soils due to the concentration of heavy metals among six land use types. The coefficient of variation and standard deviation techniques were deployed to study the degree of variation and compare the mean values of soil physical and chemical properties of twelve representative topsoils collected from six locations. All metals analyzed showed significant (p<0.05) variation in the concentration of heavy metals, CF and Igeo among land uses. Spatial distribution of heavy metals indicates areas of potential risks of harmful heavy metals in the urban environment which enhances action plan for remediation and protection of the urban environment. @JASEM
The effects of dual-fuel on improving the ballistic efficiency of a low energy sugar-based solid rocket propellant were investigated in this paper. This was achieved by establishing a threshold proportion of sucrose to sorbitol that provided the highest ballistic efficiency, using a beam load cell (model single-point 2,000 kg linearly defined by 0-20 kN force, with ±.005 percent precision). Seven different propellant formulations were prepared, loaded into the rocket motor and tested for performance. The major performance parameters of interest were the thrust, total impulse, burn time, delivered specific impulse, delivered characteristic velocity, and the chamber pressure. The formulations tested were potassium nitrate–sucrose propellant (65% KNO3 and 35% sucrose (C12H22O11)) (KNSU); potassium nitrate-sorbitol propellant (65% KNO3 and 35% sorbitol (C6H14O6)) (KNSB); modified potassium nitrate-sucrose propellant (65% KNO3, 32% sucrose (C12H22O11)), and 3% carbon (C) (MODKNSU); potassium nitrate-sucrose-sorbitol propellant (65% KNO3, 25% sucrose (C12H22O11)), and 10% sorbitol (C6H14O6) (KNERK); potassium nitrate-sucrose-sorbitol-carbon propellant (65% KNO3, 24% sucrose (C12H22O11), 10% sorbitol (C6H14O6), and 1% carbon (C)) (MODKNERK); and finally a propellant made from KNO3, sucrose (C12H22O11), sorbitol (C6H14O6), carbon (C) and iron II oxide(Fe2O3) combinations in 65, 30, 3, 1, 1% proportion respectively. The novel result obtained from these experiments was applied to boost the performance of a KNSB rocket propellant motor during a rocket launch experiment. Both static and dynamic rocket motor internal ballistic parameters were then compared. The measured delivered motor average thrust and the effective propellant burn times were recorded as: (164.15N, 3.97s); (102.95N, 6.53s); (65.66N, 9.38s); (79.09N, 3.77s); (243.98N, 3.77s) and (92.6N, 5.89s) respectively. The MODKNERK, was established to produce a most efficient motor and with the full delivery of its ballistic energy. It was also established, that the ballistic and rocket motor efficiency of a lower energy rocket motor can be improved by starting the ignition of such motor with fast burning dual-fuel rocket propellant (MODKNERK).
The effects of dual-fuel on improving the ballistic efficiency of a low energy sugar-based solid rocket propellant were investigated in this paper. This was achieved by establishing a threshold proportion of sucrose to sorbitol that provided the highest ballistic efficiency, using a beam load cell (model single-point 2,000 kg linearly defined by 0-20 kN force, with ±.005 percent precision). Seven different propellant formulations were prepared, loaded into the rocket motor and tested for performance. The major performance parameters of interest were the thrust, total impulse, burn time, delivered specific impulse, delivered characteristic velocity, and the chamber pressure. The formulations tested were potassium nitrate–sucrose propellant (65% KNO3 and 35% sucrose (C12H22O11)) (KNSU); potassium nitrate-sorbitol propellant (65% KNO3 and 35% sorbitol (C6H14O6)) (KNSB); modified potassium nitrate-sucrose propellant (65% KNO3, 32% sucrose (C12H22O11)), and 3% carbon (C) (MODKNSU); potassium nitrate-sucrose-sorbitol propellant (65% KNO3, 25% sucrose (C12H22O11)), and 10% sorbitol (C6H14O6) (KNERK); potassium nitrate-sucrose-sorbitol-carbon propellant (65% KNO3, 24% sucrose (C12H22O11), 10% sorbitol (C6H14O6), and 1% carbon (C)) (MODKNERK); and finally a propellant made from KNO3, sucrose (C12H22O11), sorbitol (C6H14O6), carbon (C) and iron II oxide(Fe2O3) combinations in 65, 30, 3, 1, 1% proportion respectively. The novel result obtained from these experiments was applied to boost the performance of a KNSB rocket propellant motor during a rocket launch experiment. Both static and dynamic rocket motor internal ballistic parameters were then compared. The measured delivered motor average thrust and the effective propellant burn times were recorded as: (164.15N, 3.97s); (102.95N, 6.53s); (65.66N, 9.38s); (79.09N, 3.77s); (243.98N, 3.77s) and (92.6N, 5.89s) respectively. The MODKNERK, was established to produce a most efficient motor and with the full delivery of its ballistic energy. It was also established, that the ballistic and rocket motor efficiency of a lower energy rocket motor can be improved by starting the ignition of such motor with fast burning dual-fuel rocket propellant (MODKNERK).
This paper reports the gaseous compositions produced from the combustion of a laboratory-synthesized potassium nitrate (KNO3)-based rocket composite propellant. The exhaust emissions produced from the combustion of 10 different propellant formulations were analyzed using an E8500 portable industrial emission analyzer. The concentrations, emission factor, and emission rates of the gaseous pollutants were computed. The measured concentrations were then compared with the stationary source limit by the Federal Ministry of Environment standard (Nigeria) to establish their impact on air quality. The obtained concentrations were as follows: hydrocarbon (HC) ranged from 56 to 290 mg/m 3 , with an the average concentration of 145.72 ± 20.12 mg/m 3 ; carbon monoxide (CO) ranged from 234 to 2030 mg/m 3 , with an average concentration of 1177.3 ± 154.2 mg/m 3 ; nitrogen oxides ranged from 19.8 to 53.7 mg/m 3 , with an average concentration of 33.9 ± 4.18 mg/m 3 ; sulfur dioxide ranged from 8.2 to 156.8 mg/m 3 , with an average concentration of 25.4 ± 14.67 mg/m 3 ; and hydrogen sulfide ranged from 1 to 6 mg/m 3 , with an average concentration of 2.44 ± 0.50 mg/m 3 . The results indicate that HC and CO emissions from the combustion of KNO3-based composite propellant represent a great threat and concern in relation to air quality. Thus, the proper management and control of rocket launches using KNO3-based composite propellants needs to be immediately addressed; otherwise, such emissions could have negative effects on the atmospheric environment of rocket routers.
This study investigated the air pollutants in the ambient air of a typical intercity highway in Nigeria. This was to assess the effect of vehicular emission on air quality along the highway. The results showed that NOX concentrations ranged from 9.9±3.2 to 33.8±3.3 µg/m3 during the wet season and 19.0±1.2 to 35.4±2.3 µg/m3 during the dry season. Sulfur dioxide measured along this highway ranged from 49.7±38.1 to 219±18.1 µg/m3 during the wet season while dry season concentration ranged from 89.1±20.9 to 225.4±57.9 µg/m3. The TSP during the wet season ranged from 54.4±25.6 to 126.8±25.6 µg/m3. These values were below the limits of 250 mg/m3 set by FMEnv., and 150-230 mg/m3 by WHO. However, the TSP measured during the dry season ranged from 85.9±44.6 to 277.8±213.5 µg/m3. The average correlations between NOX, SO2, and TSP measured during wet and dry seasons and the traffic density were 0.7, 0.6 and 0.7, respectively. Air pollution along the Nigerian highway is highly linked to vehicular activities.
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