LAUTECH Journal of Engineering and Technology (LAUJET)
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EFFECTS OF EXHAUST GAS RECIRCULATION ON PERFORMANCE AND EXHAUST GAS EMISSIONS OF SPARK IGNITION ENGINES
Get PDFThe purpose of internal combustion engines is the production of mechanical power from the chemical energy contained in the fuel. Internal combustion engines can be classified into spark ignition (S.I) engine which is the focus of this work and compression ignition engine. S.I engine exhaust gas emissions which consist of oxides of nitrogen (NOX), carbon monoxide (CO) and unburned hydrocarbons (HC) are a major source of urban air pollution. This work investigated the effects of exhaust gas recirculation (EGR), engine speed and engine load on performance and exhaust gas emissions of spark ignition engines. Eleven S.I engine parameters were considered in this work which was divided into three input parameters and eight output parameters. The effects of variations in the input parameters on the output parameters were simulated using artificial neural network software implemented in MATLAB 7.9 environment developed by the authors. From the results obtained, it can be shown that NOX emissions reduced significantly with increase in EGR level while CO and HC emission increased moderately. Specific fuel consumption increased slightly with increase in EGR level while the other four performance parameters reduced with increase in EGR. It can be concluded from this work that for improved performance and low exhaust gas emissions, S.I engines should be operated at low levels of EGR
EFFECT OF PROCESSING ON AMYLOSE, RESISTANT-STARCH, RAPIDLY-DIGESTIBLE-STARCH, AND SLOWLY-DIGESTIBLE-STARCH FOR GARI, A PROCESSED CASSAVA PRODUCT.
Get PDFThe objective was to investigate the effect of domestic processing on the digestion attributes of gari, a low-moisture food product from cassava commonly consumed in tropical developing nations, and important ethnic food amongst population groups in Europe and elsewhere.
During the production of gari, cassava-mash samples were analysed for amylose whilst pH of enzyme extracts from all samples were measured. Resistant-starch types 2 and 3 (RS2, RS3), rapidly-digestible-starch (RDS), and slowly-digestible-starch (SDS) in gari were determined.
The pH was almost stable at 5.3. SDS, RDS, RS2 and RS3 variations were 27.4-39.5, 18.2-24.7, 41.7-51.6, and 8.2-15.3 mg/100mg, respectively. Increase in RS3, lower RDS, higher SDS and RS2 suggested that gari has better potential as functional food compared to potato-chips (3.5gRS/100g), rice-cake (0.2gRS/100g), raw-banana (4.0gRS/100g), and cooked-white-rice (1.3gRS/100g). Therefore, gari may be considered for its benefits in the diets of wider population groups
OPTIMAL CAPACITOR PLACEMENT FOR POWER LOSS REDUCTION ON DISTRIBUTION SYSTEMS
Get PDFElectrical and Electronic equipments are designed to operate on specified voltage and frequency. This objective may not be realized when there is supply-demand power imbalance, with heavy power loss on the distribution system being one of the identified major causes. Power distribution system in Nigeria is characterized high power loss which consequently leads to poor quality of electric power reaching consumers. One of the identified problems has been the abnormal excessive loadings on the distribution feeders. The paper considered a novel approach to minimize power loss on the radial distribution systems. The work considered maximum loadings on each node of the distribution feeders when estimating power loss.. Further reduction in power loss was expected when optimal size and location of the shunt capacitor were determined on the considered feeder nodes. carried out on feeder nodes. From the derived basic power equations, an algorithms coded with Visual Basic Net was developed to provide simple and flexible task in determining optimal capacitor sizing and its placement on the distribution feeder that would achieve minimum power loss. The power loss before and after placing shunt capacitor optimally were determined for each feeder. Using the electric power distribution system of Ilorin, three of the distribution feeders were used as a case study, to estimate the power losses, by considering 50mm2, 80mm2, 100mm2 and 150mm2 ASCR cables. Using the developed algorithm, the appropriate node location for shunt capacitors to further reduce power loss was done. The results from the analysis showed that the considerable amount of energy can be saved by electricity utilities when the adoption of the shunt capacitor is considered on the primary distribution
TRIPLE MODULAR REDUNDANCY APPROACH FOR INTERNET CONNECTIVITY
Get PDFThis paper discusses the issue of providing tolerance to hardware and software faults in Internet system through triplicate application servers. A replication scheme (TMR) is presented, and a detailed dependability analysis of this scheme is performed. The proposed model was designed mainly for fault-tolerant Internet connectivity system where faults will not impair the continuous services rendered by the Internet system, thereby exhibiting highly varying and dynamic system characteristics. A major feature of the model under consideration is to attempt the adaptive connections of the existing Triple Modular Redundancy (TMR) scheme for the execution of redundant modules for a required level of fault tolerance.
 
Determination and Evaluation of Fuel Properties of Groundnut (Arachis hypogaea, L.) Biofuel Blended with Diesel
Get PDFVegetable oils have attracted attention as potential renewable resources for the production of alternatives for petroleum based diesel fuel. This study focused on the evaluation of fuel properties of groundnut oil and its ethyl ester blended with diesel to establish their suitability for use in compression ignition engines. Twenty biodiesel blends (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%) of groundnut oil and its ethyl ester by volume with Automotive Gas Oil (AGO) were used. The fuel properties of the biodiesel blends such as specific gravity, viscosity, cloud and pour point, flash point, heating value, sulphur content and carbon content were determined according to ASTM standards. Data were analyzed using ANOVA and correlations between fuel properties and blending ratios of groundnut biofuel with AGO were developed. Pure AGO was used as a basis for comparison. Results showed that viscosity of 10 - 30% groundnut ester-AGO blends (5.5 – 5.8 mm2/s) fell within the limit specified by ASTM standards. The heating values of groundnut biodiesel blends decreased from 38.4 – 30.07MJ/l. Groundnut ethyl-ester had higher cloud point of 7oC compared to -12oC obtained for AGO. The flash points, cloud and pour points of groundnut oil and its ethyl-ester AGO blends were higher than for reference AGO. The specific gravity obtained for all groundnut ester-diesel blends ranged from 0.8 – 0.9 and it fell within limit specified by international standards. All the biodiesel blends had sulphur contents ranging from 9.16 – 13.2% and lower than that of reference AGO. Predictive fuel properties’ models gave R2 of 0.55-0.98. Biodiesel blends with 10 and 20 percent groundnut ethyl ester content were found to have acceptable fuel properties for use as supplementary fuel in compression ignition engines
DISTRIBUTION OF RADIOFREQUENCY RADIATION AROUND BASE STATIONS IN LAUTECH ENVIRONMENT
Get PDFThis study reports the measurements of the power density around base stations located in the Ladoke Akintola University of Technology, Ogbomoso (LAUTECH) environment. Eight (8) mobile phone stations located around LAUTECH belonging to three mobile phone network providers; MTN, GLOBACOM and AIRTEL were studied. The locations of the base stations are; MTH area, NUT area, Nurudeen school area, Under G area, New LAUTECH College, School gate and Dorcas hostel. The power density around each of the base station was measured at distances of 0 and 50m from the base station. The results obtained gave power densities ranging from between 0.194 - 0.200 µW/cm2 and 0.136 – 0.151 µ W/cm2 at distances of 0 and 50m respectively. These results are much less than the 200µW/cm2 recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) thus the base stations may be regarded as not constituting any health hazard to the people around the base stations
DESIGN AND IMPLEMENTATION OF SMS BASED WIRELESS APPLIANCE CONTROL SYSTEM
Get PDFUsing GSM network, a control system that acts as an embedded system which can monitor and control electrical appliances and devices locally using built-in input and output peripheral is designed and implemented. Remotely the system allows the user to effectively monitor and control the house/office appliances and equipments via the mobile phone set by sending commands in the form of SMS messages
ASSESSMENT OF WATER CONSUMPTION PATTERN IN ILORIN, KWARA STATE, NIGERIA
Get PDFThis report presents the outcome of a survey of water use pattern in Ilorin, Kwara State. Nigeria. The water use pattern study extends to various water consumers such as residential, institutional, commercial and industrial. The study was conducted through questionnaire survey and oral interview which centered on water demand and uses. Most residents were found to use between 46 to 115 l/c/d. The high rates were common in low density areas and the low rates in medium and high density areas of the city. The daily values for commercial, industrial and institutional facilities sampled within the metropolis were 75,535; 188,735 and 161,680 litres respectively. Moreover, public water distribution system is not adequate, because majority of consumers still source water from wells or boreholes to meet their basic needs. Some mathematical models have been generated which could be used to estimate water need for planning and operational purposes. The results of the models show that water use by some categories of consumers can be estimated knowing certain variables and coefficients
EFFECTS OF COVERINGS ON RADIATION EXPOSURE RATE IN SOME INDOOR ENVIRONMENTS
Get PDFThe effects of covering materials used for the interior building surfaces; the walls, ceilings and floors of some buildings in Ogbomoso on the radiation exposure rates have been investigated in this work using an accurately calibrated scintilometer. The combinations of covering materials assessed in this work are of three categories: A – tex-coat paint, asbestos and carpet; B – emulsion paint, asbestos and bare floor and C – ceramic tiles, asbestos and carpet. The dose rate values obtained varied between 4.04±0.05 x 10-5 µ?v h-1 to 5.12±0.05 x 10-5 µ?v h-1 for A, 4.04±0.04 x 10-5 µ?v h-1 to 5.60±0.04 x 10-5 µ?v h-1 for B and 4.61±0.04 x 10-5 µ?v h-1 to 6.66±0.05 x 10-5 µ?v h-1 for C. The data obtained showed that the dose rate values are highest in the C – type buildings while the lowest values are obtained in the B – type buildings. The mean effective dose for A, B and C buildings are 0.3400±0.0018 µSv y-1, 0.3520±0.0019 µSv y-1 and 0.3735±0.0019 µSv y-1 respectively
CELLULAR DAMAGE AND STORAGE STABILITY OF LACTOBACILLUS RHAMNOSUS GG DRIED IN DISACCHARIDE MATRICES UNDER VACUUM
Get PDFThe survival of cell concentrates of Lactobacillus rhamnosus GG (LGG) in selected dissacharides after drying under vacuum was evaluated. Drying is a useful technique for preserving foods, agricultural products and pharmaceuticals. However, biological materials can be irreversibly damaged during this treatment resulting in substantial loss of viability and activity. In this paper, disaccharide systems (trehalose, sucrose and lactose) were used as protectants for L. rhamnosus GG. Among the solutes examined, trehalose improved the recovery of viable cells after drying as well as during storage at 4°C and 25°C. Stored vacuum-dried trehalose systems were found as viscous syrups which indicated that they were not glassy. Damage of cell membrane and reduction in colony sizes occurred as a result of dehydration inactivation. Comparison of the conventional techniques with flow cytometric viability assessment after drying revealed the occurrence of certain cell population which were stressed and lost their ability to grow on agar. The protecting ability of trehalose on bacterial cells was only against lysozyme and pepsin actions. These results could have some relevance, especially in underdeveloped and /or developing countries, for the production of functional confections