Activities of small scale lumber mills in the rural areas in Nigeria play a vital role in the local economy as a key rural employment generator. Unlike major saw mills in cities which have received lots of attention from researchers, policy makers and the general public, very little information is available on the activities of small scale lumber mills in the rural areas. An assessment of 7 small scale lumber mills was carried out by this study in Ibogun-a cluster of rural settlements in Ifo Local government area of Ogun State Nigeria. Preliminary investigations revealed that 42% of operators used only table saws for their operations while 52% utilized table saws, planning and smoothening machines respectively. The major power source in each of the sites visited was from air cooled diesel engines with 10-15 horse power capacity. Three major lumber sizes were identified as raw materials. The average total Energy expended daily was 318.04 MJ, average daily operational cost was ₦3436.43 ($9.4). Daily power utilization in the conversion process was estimated while the efficiencies of each site in size reduction process ranged from 85-87% respectively.
A pilot study was performed using three integrated column bioreactors with elephant grass (Pennisetum purpureum) stalks as filter media in treating abattoir effluent. The reactors (50 cm height, 10 cm diameter and a supportive gravel of 5 cm depth at the bottom) with individual volume of 3.5 L and a working volume of 3.1 L were constructed using 15 cm polyvinyl chloride (PVC) pipes. Freshly harvested elephant grass stalks were pre-treated, characterized and chopped to an average length of 20 mm - 40 mm. Wastewater was fed into the bioreactors at a constant flow rate of 0.00024 m3/hr. using a variable speed peristaltic pump with hydraulic retention times (HRT) of 15, 30, 40 and 60 hours. The results obtained indicated a maximum removal efficiency of 43.03% for BOD, 35.93% for COD, 62.42% for Protein, 39.84% for Alkalinity (CaCO3) and 63.33% for Ammonia nitrogen (NH4+) after a retention time of 60 hours. Increase in removal efficiencies with HRT time was observed for all the investigated parameters except pH, which slightly increased from a near neutral value of 5.6 to a slightly acidic value of 6.2. The Total Coliform Count also increased from 3.2 x 105 to 6.9 x 105 CFUs. The column reactor was adjudged to achieve an increasingly stable performance with time; however, further work is required to optimize the system and determine its long-term use. The authors further recommended the use of the treated effluent for irrigation of agricultural crops.
Concern on air pollution continues to receive a great deal of global interest due to its negative impacts on human health and by extension the surroundings. Recent studies reported the important correlations between air pollution and certain diseases including asthma, breath distortion, sore throat, chest pain, nausea, bronchitis and lung cancer, acute health effects include eye irritation, headache. The World Health Organization (WHO) states that 2.4 million people die yearly from causes directly attributable to air pollution. Epidemiological studies suggest that more than 500,000 Americans also die yearly from cardiopulmonary disease linked to breathing fine particle air pollution. The objective of this study is focused on the emission analysis of different ratios of two fuels: LPG (propane) and gasoline (petrol) under different loadings. The components used in the research consist of a 4- stroke, spark ignition ELEPAQ generator, carbon-monoxide analyzer (CO meter), weighing balance and particulate matter (PM) meter which measures the particulate matter. The fuels, gasoline in litre (litres) and LPG in kilogram (kilogramme) were used to assess their impacts on the exhaust gas emission released. The results revealed that particle number concentration, carbon-monoxide (CO) increased as the engine loading increases in gasoline (fuel). Using LPG, the carbon monoxide (CO) concentration level was less, significant reduction in exhaust emissions, but high temperature in the environment than gasoline (petrol) on engine loading. The engine, while running with LPG fuel showed improved engine performance in terms of – fuel economy, overall efficiency and significantly better exhaust emission characteristics, compared to that of gasoline.
Network lifetime has been an area critically and most extensively researched in wireless sensor networks (WSNs) due to the finite energy in the deployed sensor nodes. Diverse routing protocols have been proposed for use in WSNs for the main purpose of extension of the network lifetime without the degradation in the network throughput and efficiency. The aim of this paper is to evaluate the performance of RB-LEACH (a homogenous centralized routing protocol) deployed using different numbers of regions. The RB-LEACH has been implemented with 8 sub-regions and 12 sub-regions, which was compared with the performance of the RB-LEACH of 10 sub-regions. The result shows considerable improvement in the stability period of the network with a decrease in the number of sub-regions and vice versa.
Elevators installation demands a high safety requirement and manpower training. Any noticeable fault in the elevator affects not only the operations in the industries but also trigger high fatality rate among workers. In order to maintain a hitch free operation in high rise building, an elevator must be frequently and appropriately maintained to sustain its operational efficiency. In this study, attempts were made to analyse the operational performance of elevators in Nigeria with focal point on existing data domiciled in major industrial players. Key of the results emanating from this research indicates that 49% of serious injury was as a result of accidental fall during installation of elevators with high mortality rate between 2001-2006. Further investigation revealed that practicable maintenance method particularly risk based inspection must be rejuvenated with strong political will from government to enforce basic tenet of industrial safety.
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 Editor in Chief, Journal of Experimental Research Department of Anatomy, Enugu State University of Science and Technology, College Of Medicine (ESUCOM), GRA Enugu, Nigeria.
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Enugu State University of Science and Technology