Several mathematical models have been proposed for predicting highways traffic noise on highways. Performance of these models depends on location of use, hence, the need for evaluation of existing models before adoption in any location. This study evaluates the predicting accuracy of four mathematical models towards predicting highways traffic noise in Ogun State. These models include Calculation of Road Traffic Noise (CRTN), Acoustical Society of Japan-Road Traffic Noise (ASJ RTN), Federal Highway Administration (FHWA) and Consiglio Nazionale delle Ricerche (CNR) model. Traffic noise was measured using a Sound Level Meter on four major highways. Traffic data consisting of traffic volume, type of vehicle, speed, distance and road characteristics were collected and used as input to evaluate the models. Results show that the Root Mean Square Deviation (RMSD) of the CRTN model was found to be 0.37 while the value RLS90 model was found to be 0.32. In terms of two-sample t-test, the CRTN model had a value of 2.36 while the RLS90 model had a value of 2.97. The CNR and FHWA model had a RMSD value of 0.2 and 0.31 with a t-value of 2.15 and 2.62. The result of the analysis revealed that the CNR model had the best performance when compared to the CRTN, FHWA and RLS90 models, hence the model can be used as a reliable forecast tool for planning and activities aimed at mitigating highway traffic noise in the state.
Infrastructure deficit gaps in Nigeria’s electric power supply is prominent, affecting every sector of the nation’s economy ad-modum less productivity, lost and corrupt data, damaged equipment and poor power efficiency. Use of generators as alternative source of electrical power with its characteristic noise and vibration has serious health hazard and environmental impact. The intensity of noise from various generator used in small business enterprises (commercial centres) in Abeokuta metropolis was assessed using a digital sound level meter to determine the intensity of noise level from the generators. Sound emitting from each of the generators was measured from five different points. The associated noise levels at the five distances from the commercial user showed mean values of 109.86, 85.95, 83.09, 80.68 and 81.69 decibels taken at the exhaust, distances of one, two, three meters and closest distance of the generator from the commercial user respectively. Analysis of the measured generator noise loudness using the data obtained for noise level at different distances on typical noise level scale showed that 9.1, 100, 96.6 and 90.9 percents of the generators were very loud at noise at the exhaust and distances of one, two, three meters respectively. It was only at the generator exhaust that 90.9 percent there was uncomfortably loud. This high noise levels obtained necessitates acoustic muffling of the generators.
Selected physical properties of Afzelia africana seeds were determined at four moisture levels: 10.60%, 12.80%, 15.20% and 18.40% wet basis (w.b). The seeds were categorized in three batches according to their weights: Batch I (2g<m<2.99g), Batch II (2.99<m<3.99g) and Batch III (3.99<m³4.99g) respectively. As moisture content ranged from 10.60%-18.40 % (w.b), the mean values of length, width and thickness ranged from 21.782±0.91-25.225±1.11mm, 10.550±0.92-12.970±0.17mm and 7.946±1.03-10.607±0.82mm from batch I – III respectively. Arithmetic and geometric mean diameters, sphericity and projected area ranged from 13.570±0.43-15.823±0.41mm, 12.245±0.33-14.430±0.39mm, 57.80±0.07-75.60±0.03% and 186.218±28.42-256.037±12.98mm2 respectively. Unit mass, unit volume, aspect ratio and surface area ranged from 2.545±0.23g-4.515±0.09g, 7.897±0.89-12.795±1.03cm3, 49.246±5.37-51.519±1.97% and 467.285±25.72-657.734±35.59mm². Porosity, true and bulk densities ranged from 41.851±10.57-45.824±7.72%, 0.656±0.28-1.090±0.30g/cm3 and 0.305±0.08-0.431±0.18g/cm3 respectively. The highest mean value of coefficient of static friction (0.46±0.07) was recorded for iron steel structural surface for batch III, batches I and II recorded the lowest (0.32±0.04) for plywood surface. The highest mean value of angle of repose (32.1388o) was recorded for plywood surface for batch I while the lowest 25.3569o was recorded for batch II on iron steel surface among the three batches.
An Impact Test Apparatus was developed to determine the impact damage and bruise parameters of five fresh agricultural produce, namely: banana (Musa spp), tomato (Lycopersicon esculentum), sweet potato (Ipomea batatas), cassava tuber (Manihot esculenta) and lemon (Citrus limon) using Impact – Drop Height method. A constant impact energy of 0.9J – 4.5J was maintained as drop heights ranged from 0.20m – 1.00m. The bruise diameter, bruise depth, bruise width, bruise volume, bruise resistance and bruise susceptibility of banana ranged from 10mm – 18mm, 6mm – 8mm, 2mm – 4mm, 62.68mm3 – 300.87mm3, 0.014J/mm3 – 0.015J/mm3, 69.64mm3/J – 73.12mm3/J. That of tomato ranged from 10 – 26mm, 6 – 6.5mm, 2.1 – 5mm, 65.81 – 441.39mm3, 0.015 – 0.010J/mm3, 73.12 – 98.08mm3/J. That of sweet potato ranged from 8mm – 16mm, 4mm – 6mm, 2mm – 6mm, 33.43mm3 – 300.87mm3, 0.02J/mm3 – 0.014J/mm3, 37.14mm3/J – 66.86mm3/J. That of cassava tuber ranged from 10mm – 16mm, 3mm – 8mm, 2mm – 4mm, 31.34mm3 – 267.44mm3, 0.03J/mm3 – 0.02J/mm3, 38.82mm3/J – 59.43mm3/J. While that of lemon ranged from 0mm – 7.5mm, 0mm – 4.5mm, 0mm – 5mm, 0mm3 – 88.14mm3, 0J/mm3 – 0.05J/mm3 and 0mm3/J – 19.58mm3/J respectively. Results indicated that bruise parameters increased with impact energy. Tomato has the highest bruise susceptibility, followed by cassava tuber, banana, sweet potato, and lemon, but lemon has the highest bruise resistance. The results would be useful to food processors and engineers in designing packages to reduce impact damage to agricultural produce.
Sludge is water that contains suspended solids from the source water and the reaction products of chemicals added in the treatment process. And in order to treat and dispose of the solids produced from treatment plants in the most effective manner, it is important to know the characteristics of the solids that will be processed. This study is an investigation into the engineering and chemical properties of sludge collected from different water treatment plants in South-Western Nigeria. After determining the engineering and physical properties of the sludge samples, the sludge samples were also subjected to XRF analysis. It was found out that the sludge which was an alkaline silty-sandy material possessed four major oxides present in a Portland cement which include those of Lime (CaO), Silica (SiO2), Alumina (Al2O3) and Iron (Fe2O3) were also present at an appreciable quantity in the sludge ashes and this feature suggests a possible application of the sludge ash in place of cement only that the sludge remained a non-plastic material.
The quest for valorization of wastes in civil engineering has become prevalent in recent times. This study is an investigation into the potential use of recycled plastics (high density polyethylene) in the production of interlocking paving stones. After batching, 1:3:6 mix of concrete interlocking paving stones was produced in varying recycled plastics proportions of 5%, 10% and 20% as partial replacement for fine aggregates. The stones were moulded in plastic molds of size 220mm X 140mm X 60mm. It was seen that the compressive strength of the RHDPE-concrete interlocking stones at 28days of curing decreases linearly from 20.31MPa (for conventional concrete interlocking stones) to 11.37MPa (for 20% recycled plastics content) and statistically there are significant differences between the compressive strength values obtained for the interlocking stones. Concrete of 5% RHDPE content can be used in lightweight concrete and as interlocking paving stones in walkways only as it is not advisably recommended for car parks and other structural purposes as it tends to fail under heavy load.
This research focused on characterizing the raw, beneficiated and treated Nigerian bentonitic clays using Fourier Transform Infrared Spectroscopy (FTIR) with the aim of determining their mineralogical compositions for application in oil and gas drilling fluid formulation. The frequencies of absorption for all the samples in which the AIAIOH stretching band typically occurs at approximately between 3620-3630 cm-1 and for bending band is situated at approximate values of 920-930 cm-1 which indicates that all the studied bentonite samples are Al-rich montmorillonite of smectite group. The samples also showed small CO3- stretching band at approximately 1430 cm-1 indicating the presence of carbonate impurities.
An assessment of palm kernel processing and storage in South-Eastern Nigeria was carried out by investigative survey approach. The survey basically ascertained the extent of mechanization applicable in the area to enable the palm kernel processors and agricultural policy makers, device the modalities for improving palm kernel processing in the area. According to the results obtained from the study, in Abia state, 85% of the respondents use mechanical method while 15% use manual method in cracking their kernels. In Imo state, 83% of the processors use mechanical method while 17% use manual method. In Enugu and Ebonyi state, 70% and 50% of the processors respectively use mechanical method. It is only in Anambra state that greater number of the processors (50%) use manual method while 45% use mechanical means. It is observable from the results that palm kernel oil extraction has not received much attention in mechanization. The ANOVA of the palm kernel oil extraction technique in South- East Nigeria showed significant difference in both the study area and oil extraction techniques at 5% level of probability. Results further revealed that in Abia State, 70% of the processors use complete fractional process in refining the palm kernel oil; 25% and 5% respectively use incomplete fractional process and zero refining process. In Anambra, 60% of the processors use complete fractional process and 40% use incomplete fractional process. Zero refining method is not applicable in Anambra state. In Enugu sate, 53% use complete fractional process while 25% and 22% respectively use zero refining and incomplete fractional process in refining the palm kernel oil. Imo state, mostly use complete fractional process (85%) in refining palm kernel oil. About 10% use zero refining method while 5% of the processors use incomplete fractional process. Plastic containers and metal drums are dominantly used in most areas in south-east Nigeria for the storage of palm kernel oil.
The field performances of agricultural field machineries in South -East agricultural zone of Nigeria were assessed, to enable farmers and agriculturists select suitable farm machines/implements based on soil conditions/characteristics for their agricultural activities. The various implements studied include; disc plough, 2-gang tandem disc harrow, ridger, rotovator and 6-row combine seed planter. Three different makes and models of tractors namely: New Holland (model-NH5610SE and capacity-55.9kw), Massey Ferguson (model-MF430E and capacity-55.2kw) and Mahindra (model-NH7570E and capacity-55.9kw) with 3- point hitch systems and average age of 1.3 years were used to study the field performances of each of the implements, in five different states that made up the study area. The field performances studied include; implement’s working speed, operation time, depth of cut, effective and theoretical field capacities, field efficiency, fuel consumption rate, implement power requirements, and wheel slippage, under different soil conditions. Results obtained revealed that the disc plough had field efficiency range of 85.74% to 88.55%, effective and theoretical field capacities range of 0.846 to 1.164ha/hr and 0.961 to 1.319ha/hr respectively; and the highest field (ploughing) efficiency was obtained in loamy-sandy soil when the plough was operated with the Massey Ferguson tractor. Harrow recorded field efficiency range of 80.17 to 91.38%, effective and theoretical field capacities range of 0.931 to 1.458ha/hr and 1.151 to 1.667 ha/hr respectively; and the highest field (harrowing) efficiency was obtained on sandy-clay soil by New Holland tractor. Ridger recorded 83.65 to 88.82% field efficiency, 0.932 to 1.322ha/hr effective capacity and 1.073 to 1.504ha/hr theoretical field capacity; and sandy-clay gave the highest field (ridging) efficiency when operated with a New Holland tractor. The rotovator had field efficiency range of 81.10 to 89.81%, effective and theoretical field capacities range of 0.759 to 0.902ha/hr and 0.758 to1.039ha/hr respectively; and the highest pulverizing efficiency was achieved on the clay-loam soil with a Massey Ferguson tractor. The planter recorded 80.63 to 89.37 field efficiency,1.012 to1.481ha/hr effective field capacity and theoretical field capacity of 1.22 to 1.716ha/hr. Ploughing gave the highest average fuel consumption rate of 22.72L/ha (8.89L/hr), followed by harrowing with average consumption of 19.57L/ha (8.04L/hr), ridging recorded 19.42L/ha (7.97L/hr), rotovator had 16.79L/ha (7.19L/hr) and least was planter with average consumption rate of 15.10L/ha (6.26L/hr). More so, all implements recorded highest tyre slippage in sandy-clay soil, followed by loamy-sandy and the least slippage was recorded in the clay-loam soil. Results finally revealed that the highest draft force (10.8kN/m) was obtained by the plough, followed by the harrow and ridger with equal draft force values of 10.5kN/m respectively and least draft was recorded by the rotovator (5.1kN/m).
Physical and aerodynamic properties of African breadfruit (Treculia africana) seeds were studied at four moisture levels: 12.50, 15.00, 17.50 and 20.10% dry base (w.b). As moisture content increased from 10.50 to 20.10% (w.b), the average weight, major diameter, minor diameter, intermediate diameter, geometric mean diameter, arithmetic mean diameter of the seeds ranged from 0.35±0.08 to 0.60g±0.04g, 8.08±0.90 to 10.05±0.60mm, 4.04±0.53 to 5.00±0.10mm, 2.96±0.43 to 4.60±0.40mm, 4.52±0.45 to 6.03±0.20mm, 5.03±0.45 to 6.55±0.50mm respectively. Also the equivalent diameter, surface area, sphericity, projected area and aspect ratio of the seeds ranged from 4.75±0.42 to 6.03±0.41mm, 64.19±12.64 to 114.25±10.00mm2, 56±8.00 to 60±6.00%, 25.64±5.10 to 39.47 ± 3.80mm2, and 50±0.08 to 50±0.01mm respectively. The volume ranged from 0.35 ± 0.014 to 0.73 ± 0.014cm3, while the true and bulk densities ranged from 1.099 ± 0.141 to 1.110±0.424g/cm3 and 0.835±0.43 to 0.938±0.21g/cm3. Porosity decreased from 15.01±1.5 to 5.60±0.4% as moisture content increased from 10.50 to 20.10% (w.b). The angle of repose ranged from 39.80 to 60.10o with increase in moisture content. The optimum parboiling time, temperature and moisture content for hulling African breadfruit seeds were determined as 7.5minutes, 57.5oC and 20.10% (w.b) respectively. The terminal velocity of the seeds and kernels ranged from 12.5 to 17.02m/s and 11.40 to 13.36m/s. Drag coefficient and drag force of the hulls ranged from 0.1 to 0.7 and 0.518×10-4 to 0.858 ×10-4N, while the drag coefficient and drag force of the seeds and kernels ranged from 0.09 to 0.2, 4.50 ×10-4 to 6.00×10-4N; 0.2 to 0.3 and 4.0×10-4 to 5.10×10-4N respectively. This indicates that optimum separation can be achieved effectively without any loss of the seeds if the results obtained are properly applied in processing of African breadfruit.
The Editor in Chief, Journal of Experimental Research Department of Anatomy, Enugu State University of Science and Technology, College Of Medicine (ESUCOM), GRA Enugu, Nigeria.
Editorial Secretary: email@example.com
Enugu State University of Science and Technology