LAUTECH Journal of Engineering and Technology

SENSITIVITY ANALYSIS OF HYBRIDIZED WIND/PV ENERGY SYSTEM FOR POWERING TELECOMMUNICATION MAST IN LAGOS SOUTH-WEST NIGERIA

O. Olaogun — 2022-06-28

Power delivery micro-grid of hybridized wind and solar system installations keep growing worldwide. There is a great economic advantage in the use of cleaner renewable energy for power generation in the telecommunication industries, especially in remote areas. This studyanalyses the effect of three wind speed fluctuationsor levels on a hybridizedwind energy system’s electricity production for a typical three (3) BTS telecommunication mast using Hybrid Optimization Model for Energy Resources (HOMER)PRO software in Lagos south-western Nigeria as a case study. The economic implication of energy at the different wind speed levels investigated was also derived. From the obtained results, a wind speed of 4, 4.22, and 5 m/s gave an annual electric production of 39,950, 39,050, and 39,250 kWh and energy cost of 195, 192, and ₦175, respectively. This result is useful for the techno-economic operation of hybridized wind/solar system powered by three (3) BTS telecommunication masts.

AN EXPERIMENTAL INQUIRY INTO SURFACE ROUGHNESS OF PAINT-FINISHED MILD STEEL BY SOME TOP AUTOBODY SPRAY PAINTERS IN KADUNA METROPOLITAN AREA, NIGERIA

T. N. Guma — 2022-06-28

Body finish appeal is one of the first noticeable things about any automobile. Most factory autobody painting is highly automated, so aesthetically appealing body finishes of high quality are efficiently achievable with high production rates. However, autobody painting for maintenance or repair in Nigeria is mostly done using manual skills and minimally automated facilities, with a high chance of ending up with low-quality or unappealing body finishes. The purpose of this paper is to present an experimental comparative study about the average surface roughness of paint-finished auto bodies by three top artisanal autobody spray painters, named MA Motors, Alsarafa Body Painters, and IBK Motors in Kaduna metropolis, Nigeria, relative to factory-painted vehicles at Peugeot Automobile Nigeria (PAN) Plc and relevant engineering standards. A cold-rolled mild steel sheet was procured for the study as the most common but corrosion-susceptible autobody material. The sheet was ascertained through nominal composition analysis and was used to produce four similar-sized sheet samples. The samples were individually taken to each of the spray painters and PAN, where they were surface-cleaned, painted, and cured according to the usual methods and standards used there in paint-finishing auto bodies. The surface roughness of the paint-finished samples was measured at 20 different points on each sample with the CRV-135 surface roughness tester and analyzed statistically in terms of the mean value (Ra), root mean square, depth to peak ranges, skewness, kurtosis, and variance. The obtained results indicated that the paint finishes from IBK Motors, Alsarafa Body Painters, MA Motors, and PAN had Ra values of 1.368µm, 1.4725µm, 1.6495µm, and 1.258µm, respectively. The analysis also indicated that all the paint-finished surfaces had minimal roughness, uncharacterized by excessive variations, peaks, and valleys, about their flat average values. The analysis finally indicated that autobody paint finishes by the spray painters are of similar and high quality by engineering standards and comparable to finishes at PAN. The paper provides useful insight into the surface roughness of paint-finished auto bodies by the spray painters as a fundamental quality control parameter that should be imbibed by all in the auto-body painting business, especially in Nigeria, to meet requirements by standards, customers, and users.

THE STRENGTH CHARACTERISTICS OF GLULAM AND BOLT- LAMINATED BEAM

John Wasiu — 2022-06-28

This research presents the strength characteristics of Glulam and Bolted Beam timber specimens. The most common connection method in timber construction is the nail. It is imperative to explore other methods such as glue and bolt in order to avert the disadvantages of nails such as labour intensive and increase in cost. Experimental investigation was carried out on three selected Nigeria timbers; Ceiba Pentandra, Terminalia ivorensis and Tectona grandis. The specimen was prepared in sizes as either glued, bolted or solid connection. Moisture content, density, compression parallel and perpendicular to grain and flexural tests were carried out in the laboratory. The glulam beam specimen; Ceiba Pentandra, Terminalia ivorensis and Tectona grandis showed some positive potentials for application than the bolt-laminated beam connection. It was concluded that bolted connection can be improved by increasing bolt sizes and connection points.

MODELLING AND OPTIMIZATION OF COEFFICIENT OF PERFORMANCE OF LOWER TEMPERATURE CYCLE OF TWO-STEP REFRIGERATION SYSTEMS

A. D. Ogunsola — 2022-06-28

The coefficient of performance (COP) of a single-stage refrigeration system is low, thus there is a need for two-step refrigeration systems when there is a desire to have an evaporator temperature that is below -25 oC. The COP of the lower temperature cycle of the two-step refrigeration systems is a function of the COP of the refrigeration systems.This research aimed at optimizing COP of the lower temperature cycle of two-step refrigeration systems using eco-friendly refrigerants.Thermodynamic analysis of these refrigeration systems was performed by varying seven operating parameters. R-134a was used in the high-temperature cycle (HTC) and R-23 was used in the low-temperature cycle (LTC). The coefficient of performance of the lower temperature cycle (COP.REF[LTC]) of the refrigeration systems was optimized using Half Factorial Design of Design-Expert 12.0.1. The influence of the condensing temperature (TC,HTC),evaporating temperature (TE,HTC), cascade temperature difference (∆TCAS,DIFF), evaporating temperature (TE,LTC), superheating temperature (TSUP,LTC), sub-cooling temperature (TSUB,LTC), and refrigerant mass Flow rate (ṁHTC)was investigated on the values of COP.REF[LTC] of the refrigeration systems. The highest value of COP.REF[LTC] (18.1) was obtained under optimum conditions of the 30 TC,HTCoC , -40 TE,HTCoC, 0 ∆TCAS,DIFFoC, -50 TE,LTCoC, 0 TSUP,LTCoC, 20 TSUB,LTCoC and 0.01 ṁHTC kg/s.The study revealed that all the factors having interaction with TC[HTC] and TE[HTC] have a great influence on the value of COP.REF[LTC]

FILE ENCRYPTION AND HASH SYSTEM USING JAVA PROGRAMMING LANGUAGE FOR IMAGE STEGANOGRAPHY

O. K. Adejumobi — 2022-06-28

Due to the rapid development and rapid popularization of the information technology, internet and digital media have become an important tool for military, commercial, individuals and many other organizations to obtain and transmit information. However, digital communication via the Internet is vulnerable to eavesdropping, malicious interference and other activities. As a result, data transmission protection and information security issues become a bottleneck than ever before. This paper presents file encryption and Hash system (Image Steganography) via Least Significant Bit (LSB) approachto increase the amount of text file the cover image can conceal. The software used consists of two sections: the Encode section (embedded text file by using an image as cover) and the Decode section (extract the embedded text from the cover image) which is implemented through NetBeans IDE using Java Programming Language.The different results obtained when the proposed device was tested revealed that it worked according to the design specifications.

DIFFERENTIAL MATURITY ACROSS LATERITIC PROFILES FROM ILORIN, NORTH CENTRAL NIGERIA

O. A. Odediran — 2022-06-28

This study characterizes the three distinct horizons of the lateritic profiles within the study location with the view to determining their relative degrees of laterization. The three distinct horizons (the upper crustal, middle gravelly and basal less/non gravelly) were subjected to series of geotechnical tests to determine parameters such as Grain size distribution, Atterberg limits, Specific gravity, California bearing ratio, Compaction and Shear strength. The results of the tests elucidated a useful connection between the parameters determined and the degree of laterization. The middle horizon, which is the gravelly horizon, has the highest specific gravity out of the three horizons and a lower clay content than the basal less/non gravelly horizon, both of which are indicative of a higher degree of laterization.It also shows relatively improved and enhanced values for the other parameters such as California bearing ratio, Shear strength and Atterberg limits, which further indicates that the gravelly horizon has attained a higher degree of maturity compared to the others. It is thus expected to have the best engineering performance

MODIFICATION OF BLADE CHORD INFLUENCE ON THE PERFORMANCE AERODYNAMICS OF VERTICAL AXIS WIND TURBINES

Okeoghene Eboibi — 2022-06-28

Performance aerodynamics of VAWTs is given important considerations whenchoosing design parameters for the manufacturing of VAWT to effectively and efficiently perform after installation. Blade chord is amongst the many design parameters that can affect the CP of VAWTs in relation to wind harvest and energy yield. This study examines the influenceblade chord modification can have on the PA of wind turbines. The VAWT blade chord of NACA0022 was modified and two configurations of rotors, one with C = 0.03m and the other of C = 0.04m were tested in a low speed and low turbulent intensitytunnel at several wind speeds. An appropriate performance measuring techniques was used to conduct the tests on the two VAWT configurations. The results showed substantial differences in the measured performance efficiency of the two configurations. The two rotorsreached peak performances at the highest tested freestream speed of 8 m/s. The VAWT configuration of C = 0.04m attained higher performance with peak CP = 0.326 at λ = 3.75 while the C = 0.03m showed lower peak CP = 0.26. Changes in the CPwere seen in relation to changes in the free wind speeds.Also the peakperformanceschanged positively as the wind speed is increased. The curves of plot of the CP - λ is observed to close up at region of the peak performances. The CP, the performance efficiency and aerodynamics of the two rotors and configurations are shown tohave been visibly affected bythe modification of the blade chord.

EFFICACY AND EFFECT OF SELECTED BIO-COGULANT ON TREATMENT OF APONMU RIVER

E. O. Fakorede — 2022-06-28

In the wastewater treatment process of coagulation-flocculation-sedimentation, natural coagulants may be used to reduce turbidity. Manihot Esculenta (cassava peel) and Citrus Aurantium Dulcis (orange peel) were employed as natural coagulants for the treatment of Aponmu river. The best overall results were obtained when alum was partially replaced with cassava peel (70% AL30% CA), with all parameters (BOD; 6.1mg/L, COD; 9.9mg/L, hardness; 85.6mg/L, and Cu; 0.07mg/L, at pH of 6.3) meeting WHO drinking water standards and accepted practices for water and wastewater examination. However, alum's negative environmental effects on the production of non-biodegradable sludge and lingering effects on treated water are greatly reduced by partial substitution.

PPLICATION OF TRICKLING FILTER WITH HYBRID BIOFILM SUPPORT MEDIA IN THE TREATMENT OF PETROLEUM EFFLUENT

O. L. Okan — 2022-06-28

The use of biological trickling filter (TF) system in the treatment of petroleum effluent using Luffa cylindrica-polystyrene hybrid as biofilm support medium for microbiological growth was evaluated. The efficiency of the treatment process was measured in terms of turbidity, chemical oxygen demand (COD) and biological oxygen demand (BOD₅). The TF was set up with Luffa cylindrica-polystyrene hybrid biofilm support. The pilot scale trickling system was performed at an ambient temperature and the effluent from the system was measured for turbidity, COD and BOD₅. The result showed that the turbidity of the effluent was reduced to 94 % at a hydraulic retention time of 6 hrs. The COD was also reduced from 327-26 mg/l at 6 hrs. representing 92 % reduction in the COD value. The results obtained also showed that the TF achieved 78 % reduction in BOD₅.Therefore, the biological trickling filter treatment process appears to be a promising wastewater treatment method for petroleum effluent with respect to the turbidity, COD and BOD₅ removal

OPTIMIZATION AND CHARACTERIZATION OF SYNTHESIZED BIODIESEL PRODUCED FROM REFINED PALM KERNEL OIL

E. C. Udochukwu — 2022-06-28

In this study, response surface methodology (RSM) was used to study the transesterification reaction of refined palm kernel oil for biodiesel production. The three main factors that drive the conversion of triglycerides into fatty acid methyl esters (FAME) were studied according to a full factorial design at two levels. These factors were catalyst (NaOH) concentration, temperature and reaction time. Analysis of variance (ANOVA) was used to determine the significance of the factors and their interactions which primarily affect the first of the two transesterification sets. The effect of reaction parameters (molar ratio, catalyst weight and reaction time) was studied using RSM while the reaction temperature was kept constant at 60^oC. Optimum methyl ester yields 93% was obtained at oil to methanol molar ratio of 1:3(0.33), a catalyst load of 2.3g and reaction time of 140 minutes. The optimum methyl ester was characterized for fuel properties and the results obtained ascertain the eligibility of palm kernel oil methyl ester for use in diesel engines since they were within the acceptable standards set by American Society of Testing and Material (ASTM D 6751). And also, the study showed a good agreement with the experimental results, demonstrating that this methodology may be useful for industrial process optimization.

OPTIMIZATION AND PROGNOSTIC MODEL FOR SPLITTING TENSILE STRENGTH OF CONCRETE PRODUCED FROM GRANITE AND RECYCLED CONCRETE AGGREGATE

S. O. Odeyemi — 2022-06-28

Using recycled concrete aggregates from structural demolition wastes is presenting a potential application in the building industry as a substitute for natural aggregates. It preserves natural resources and brings about a reduction in the space needed as landfill disposal sites. This research was aimed at developing a prognostic model for splitting tensile strength of concrete produced from granite and recycled concrete aggregate. Thirteen rounds of experiments were considered utilizing the Central Composite Response Surface method. Granite was replaced with Recycled Concrete Aggregate (RCA) in varying proportions from 0% to 100% while the water-cement ratio (w/c) was varied from 0.3 to 0.7. Samples were subjected to test after 7, 14 and 28 days curing. It was observed that with a surge in the fraction of RCA, the splitting tensile strength reduced at all levels of w/c ratio. 30% RCA at 0.5 w/c gave the optimum combination that resulted in the highest splitting tensile strength of 2.11 at 28 days. This result is 7.9 % lesser than the control splitting tensile strength of 2.29