LAUTECH Journal of Engineering and Technology (LAUJET)
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SIMULATION OF A SENSIBLE HEAT THERMAL ENERGY STORAGE SYSTEM USING MATLAB’S BLOCK-ORIENTED APPROACH
Get PDFThis paper presents the dynamic simulation of the mathematical model of a solar water heating (SWH) system consisting of a solar collector and a thermal storage tank developed using MATLAB's block-oriented technique according to the law of energy conservation. The governing heat balance equations are given along with the assumptions applied in the model. As a case study, this paper analysed the SWH system performance under the climatic condition of Abeokuta for the design month of December. Global Horizontal Irradiation data for Nigeria were used to determine the average daily solar radiation intensity for the month. The results shows that a collector tilt angle of 7degrees can receive more energy with a thermal efficiency of 0.8. The results demonstrate that at the highest solar radiation intensity, the system's maximum temperature output was 61.98 °C. From the result obtained, it can be concluded that a SWH system of collector area 1.5 m^2 has the ability to heat 150 liters of water to a temperature of 60? in the month with the highest average sunshine hours in Alabata, Abeokuta. The simulation results can support the selection of appropriate components and predict the operation of the solar water heating system to be built
VEHICLE ACCESS CONTROL AND SECURITY SYSTEM: UNIVERSITY OF LAGOS SECURITY GATE AS A CASE
Get PDFNigeria (and in extension Africa) is grappling with security challenges – kidnapping, terrorism, militancy, porous border. Advances in information technology has highly upgraded the way crimes are perpetrated nowadays. One of the prominent issues identified is lack of adequate surveillance technology or a harmonized national database to rely on for thorough investigation. This paper aims at exploring and proffering a robust electronic gate access system that collects and archives relevant data securely, which can be retrieved for helpful leads, for example, during a security breach. Powered by OpenALPR API and based on SDLC principles, the system employs Raspberry Pi, biometric and number plate scanning technologies to create a working prototype that could be deployed in schools, offices, military installations, oil rigs, worship centres, and public car parks. Data collected could help the school management and government in physical planning – vehicles and drivers can be easily identified and tracked. This system will help boost Nigeria's national security – foreigners can be clearly differentiated from citizens. This alternative solution to our porous border crisis also helps plug revenue leakages in government spending and optimize resources. A locally developed solution like this will help minimize cost for institutions relying on them to address similar challenges
PROCESS OPTIMIZATION OF OIL EXPRESSION FROM WATERMELON (CITRULLUS LANATUS) SEEDS
Get PDFWatermelon fruit contains large quantities of seeds and these seeds are under-utilized. It contains reasonable amount of oil (22%) which if expressed will serve as vegetable oil for human consumption or biodiesel for powering agricultural machines and boost the income of the farmers. The main objective of this research work is to study the interaction effect of operating parameters on the mechanical oil expression from the seed. The variables considered include applied pressure (85.00, 90.00, 95.00, 100.00 and 105.00 kN/mm2), roasting temperature (70.00, 80.00, 90.00, 100 and 110 °C) and moisture content (6.00, 8.00, 10.00, 12.00 and 14.00 %). A total sum of 20 batch experiments were carried out and the maximum oil yield was 13.49% (at corresponding moisture content of 6.00%, roasting temperature of 85.00oC and applied pressure of 105.00 kN/mm2 respectively) and minimum oil yield obtained was 9.41%.(at corresponding moisture content of 14.00%, roasting temperature 80 °C and applied pressure of 85.00 kN/mm2 respectively). While the optimum oil yield of 12.42% was obtained from the expression at corresponding moisture content of 6.00%, roasting temperature of 80.00ºC, and applied pressure of 105.00 kN/mm2. The result showed that the three independent variables had significant effect on oil yield and regression model equation was developed to predict the oil yield from watermelon seeds at known variables
BIO-TRANSFORMER OIL PRODUCTION BY ENZYMATIC TRANSESTERIFICATION OF PAPAYA SEED OIL
Get PDFBio-transformer oil from vegetable oil has received quite attention as a substitute to mineral based transformer oil with a view of minimize mineral based oils and reduce greenhouse gases pollution. The seeds of papaya are potential feedstock for bio-transformer production owing to their high lipid contents and available. In this study, papaya seed oils was extracted via soxhlet apparatus using n-hexane and the oil yields were in between 34–35% which is commercially viable. The oil extracted was transesterified using immobilized Candida rugosa lipase as a catalyst at room temperature with various molar ratios of methanol to oil. The highest bio-transformer oil yield for papaya seed oil was found to be 96% at methanol-to-oil ratios of 6:1. The results obtained from the characterization of RPSO bio-transformer oil was analytically compared with that of the transformer mineral oil and ASTM standard requirement. Similarities and differences have been discussed. Owing to comparable results in the RPSO bio-transformer oil, mineral transformer oil studied and the ASTM standard requirement and its increasing breakdown voltage with increasing temperature application. The study revealed that papaya seed oils have the potential of being used as alternative feedstock for bio-transformer production
DYNAMICS OF A SIMPLY SUPPORTED TWO PARALLEL BEAMS WITH VARIABLE ELASTIC INTERCONNECTED LAYER UNDER A MOVING MASS
Get PDFIn the paper, dynamics of two parallel beams which is interconnected through a nonlinear variable viscoelastic Winkler-type layer under a moving concentrated load is investigated. The elastic characteristics of a simply supported Euler-Bernoulli beam system have been applied. The motion characteristics due to force of excitation on the system is described by a coupled governing fourth order partial differential equations of motion with variable coefficient. A solution scheme involving seperable method have been applied to obtain a coupled coupled second order ordinary differential equations. The decoupling and simplification of the coupled system yields an uncoupled sets of second order ordinary differential equations and this has been attained using an asymptotic method of Struble. A semi analytic differential transform method is applied to solve the resulting equations. A numerical experiment is explored to demonstrate the simplicity and efficiency of the method employed. The effects of various parameters including speed of the moving load, inertia of the moving load, stiffness and viscoelastic parameters of the interconnected layer were obtained. The result indicates that increasing the load mass has caused a decrease in the response amplitude of deflection of the two beams and this is found to be in good agreement with the existing results
THE STUDY OF RHEOLOGICAL PROPERTIES OF BITUMEN BLENDS MODIFIED WITH DISSOLVED PLASTIC WATER SACHET
Get PDFRutting, which is permanent deformation or consolidation of asphalt pavement, is one of the flexible pavement failures. Research has shown that one of the ways of resisting this failure is by modifying the rheological properties of bitumen. This modification can be achieved by the addition of dissolved plastic water sachet (DPWS), a well-known waste in Nigeria, to bitumen. This study was conducted to investigate the effect of DPWS on the rheological properties of bitumen and at the same time reduce the environmental hazard associated with PWS disposal with consequential pavement material improvement. Bituminous blends containing DPWS at various percentages 0, 1, 3, 5, 7, 9, 11, 13, 15 and 17% by weight of conventional bitumen were used for the study. Tests on rheological properties such as dynamic viscosity, phase angle, peak shear stress and peak shear strain were carried out on unmodified and DPWS modified hot and warm bitumen blends to determine the corresponding complex shear modulus and complex shear modulus elastic portion. Results obtained from the tests were compared between control sample (0% DPWS) and DPWS modified bitumen samples. The test results showed that the dynamic viscosity increased upon addition of the DPWS at 135°C and at 165°C, it initially increased upon addition of DPWS up to 7% before it became constant till 17% DPWS addition; and the phase angle decreased upon addition of DPWS at both 135°C and 165°C for hot mix bituminous samples. Likewise, for the warm bituminous samples, the absolute viscosity increased and phase angle decreased upon addition of DPWS at both 135°C and 165°C. The best complex shear modulus elastic portion results occurred upon 9% and 17% DPWS addition for hot mix bituminous samples and upon 5% and 17% DPWS addition for warm mix bituminous samples when subjected to temperatures of 135°C and 165°C respectively. These percentages are the best to resist rutting on our traffic roads from this study
MINIMISING ENVIRONMENTAL EFFECTS OF NANOMATERIALS: A REVIEW
Get PDFNanomaterials play very important role in chemical industries, agrochemical products, pharmaceutical drugs, materials science, engineering and nanotechnology. There is a recent increase in the utilization of nanomaterials for food and nutraceutical materials, energy, biomedical, cosmetics, textiles and health products. Nanotechnology is a potential area that revolutionises almost every sector of life and is predicted to become a major economic force in the near future. Nanomaterials are dispersed or solid particles with a size range of 1-100nm. Toxicity and ecotoxicity of some nanomaterials are well known. Their discharge into the environment pose serious threat to human life and environment. As such, it has become imperative to have a critical evaluation of the current states of knowledge with respect to the exposure and effect nanomaterials on the environment. The present review focused on reducing environmental problems associated with production, utilization and waste products disposal of nanoparticles. Sequel to environmental challenges posed by the use of nanomaterials in nanotechnology, efforts should be geared towards environmental remediation, efficient conversation of biomass, green chemistry, mandatory report of information about nanomaterials, modeling approach specific for NMs as well as standardized guidance describing specific requirements for the testing of fate and effects of Nanomaterials
GOLD IN PLANT: USING A PLANT SPECIES (Funtumia elastica) IN PROSPECTING FOR GOLD MINERALISATION AROUND IPERINDO, SOUTHWESTERN NIGERIA
Get PDFIperindo gold deposit is one of the few primary gold mineralization deposits in Nigeria and the area is underlain by rocks of Precambrian basement complex. Despite previous studies on geology, petrology, mineralogy, petrochemistry, geophysics and geochemistry, no attempt has been made on biogeochemistry of plant present in this area using Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDX). This work is therefore targeted at prospecting for gold using bark-scrapings of wild-native, deep rooted and perennial plant species known as Funtumia elastica. Rock units such as faulted migmatite gneiss, banded gneiss, granite gneiss, biotite-hornblende-gneiss, mica schist, quartzite/quartz schist and granite were identified. Eight representative samples of the tree bark were scraped to collect the soft outermost layer. The samples were air dried to prevent fungal and microorganism growth which can contaminate them. Laboratory preparation involved oven-drying at 105?C for 24 hours. The dried samples were pulverised and sieved using ? 125 ?m mesh size. The carbon coated samples were scanned at a magnification of ? 1000 times its original size to study the plant mineralogy and to infer gold mineralisation in underlying regolith or bedrock.Surface morphology of the samples as revealed by SEM is homogeneous in composition. Two contrasting compositions are common to all the SEM images studied- an embedded grain clusters showing bright resolution within a matrix of dull resolution. EDX showed average concentration (wt %) of elements such as Ca (11.91), C (59.9), O (21.06), K (1.01), Si (0.14) and Te (6.03). Presence of Te which is associated with gold mineralisation indicates possibility of detecting gold in locations where Te is available
SUITABLE MODEL FOR THIN LAYER DRYING KINETICS OF WHITE AND PINK-FLESHED TANNIA (XANTHOSOMA SAGITTIFOLIUM) CORMELS
Get PDFDrying is an essential unit operation in the conversion of fresh tannia (Xanthosoma sagittifolium) cormels into flour with the attendant benefits of improved shelf life and better storability. Information on the drying kinetics of the cormels will foster a good understanding of its behaviour during drying. Rate of moisture loss during the process can also be described by appropriate models. This study therefore, investigated the thin layer drying kinetics of two cultivars of tannia cormels at different temperature levels and determined the most suitable model for its prediction. White and pink-fleshed cormel slices of 3mm thickness were dried at 60, 70 and 80oC temperature levels. Data obtained from the drying experiments were fitted into ten selected models namely Newton, Page, modified Page, Logarithmic, Henderson and Pabis, Midilli, Verma, Two term, Thompson, and Wang and Singh models. The highest and the lowest drying rates were obtained at 80 and 60oC respectively. Page and modified Page models were the most suitable models for describing the drying behaviour of both tannia cultivars with highest R2 in excess of 0.9941 and lowest error estimates (RMSE?0.0251; ?^2?0.0008; MBE?0.0060). The drying took place predominantly in the falling rate period which indicated that moisture removal from tannia cormels occurred mainly by diffusion mechanism
REMOVAL OF COD FROM PHARMACEUTICAL WASTEWATER USING SUGARCANE BAGASSE AND BETONITE CLAY
Get PDFWater pollution is a major concern because of its negative effect on humans, plants and aquatic creatures. The concentration of COD in the wastewater is an indication of its impurity. Various pollutants impart COD to the water; hence, its removal is synergistically adequate for the removal of these impurities (organic and inorganic). The cost of adsorbents and the problems associated with their regeneration had led to the search for alternate low-cost adsorbents. This study involved the treatment of wastewater obtained from a pharmaceutical industry in Ilorin, Nigeria using sugar-cane bagasse and clay as adsorbents for the reduction of COD to a permissible level set by the World Health Organization for reuse as irrigation water for agricultural activities. For the treatment process, 27 experimental runs were designed, executed and analyzed to identify the best operating condition that brings about the lowest residual COD concentration. An optimum COD removal response of 97.8 % was obtained at adsorption conditions of adsorbent loading 0.75 g/mL, temperature 45 ? and retention time of 120 min. The developed composite adsorbent reduced the COD content to a permissible level