Oluremilekun Ropo Oyetunji - Academia.edu (original) (raw)

Papers by Oluremilekun Ropo Oyetunji

Energy Conversion and Management, Aug 1, 2022

FUTA JOURNAL OF ENGINEERING AND ENGINEERING TECHNOLOGY, Nov 30, 2020

The use of biomass for energy generation has been considered as a promising alternative to fossil... more The use of biomass for energy generation has been considered as a promising alternative to fossil fuels due to its availability and characteristic low cost. However, ash-related issues such as slagging and fouling generated during biomass combustion results in decreased combustion efficiency, power instability and even unscheduled failure. This study focused on the influence of kaolin additive on the ash yield during co-combustion of palm kernel shell (PKS) and cashew nut shell (CNS). The CNS, PKS and kaolin of different particle sizes were mixed under varying combustion temperature using D-Optimal design. The minimum ash yield of 11.50 % was obtained when CNS, PKS, kaolin, particle size and temperature were 50.00%, 40.00%, 10.00% 5.00 mm and 900oC, respectively. The ash yield was best described by the quadratic model with correlation coefficient (R2) and adjusted R2 of 0.93371 and 0.8984 respectively. According to the XRD results, the formation of potassium and aluminium tectosilicate (KAlSi2O6) in the CNS-PKS additive mixture ash prevented the release of potassium chloride which is known to increase ash deposition and slagging. The results of optimization indicate that at least 10% kaolin addition is needed to significantly reduce ash yield in the fuel mixture.

Archives of current research international, Aug 29, 2018

European Scientific Journal ESJ, 2019

The lethargic modes of medical waste disposal in many developing countries have been a cause of c... more The lethargic modes of medical waste disposal in many developing countries have been a cause of concern to many regulatory agencies. In this study, effect of reactor temperature on pyrolysis of lignocellulosic medical waste in a fixed bed reactor was investigated. Gauze bandage was procured from AKOL Pharmacy, Ogbomoso, SouthWestern Nigeria. Samples of the gauze bandage, 40 g each at a time, were fed into a retort and the retort inserted into a developed fixed bed reactor for pyrolysis at different temperatures (300, 400, 500 and 600 o C) with a residence time of 15 minutes. Tar, gas and char yields were weighed using an electronic balance (WT20002T, RS232C) and were further expressed in percentage of the initial weight of the sample. Results showed that tar and gas yields increased with increasing reactor temperature while char yield decreased with it. Both intraand extra-particle secondary reactions were insignificant and therefore could not influence the yield spectra of products. The highest yield of tar, gas and char were 52.08, 28.42 and 52.7%, respectively while the lowest yield were respectively 30.50, 16.80 and 19.50%. Lignocellulosic medical waste can be a viable source of biofuels and raw materials respectively for sustainable development and for chemical industries.

Journal of Engineering Research and Reports, Jul 5, 2023

Introduction: Cowpea decorticating is a crucial post-harvest process that involves removing the s... more Introduction: Cowpea decorticating is a crucial post-harvest process that involves removing the seed coats from the kernels to produce ready-to-use cowpea products such as flour, grits, and protein concentrates and food products such as Akara and Moinmoin in south western Nigeria. Methodology: In this study, a locally developed cowpea decorticator was tested and evaluated using small oloka (a Nigerian local cowpea breed) cowpea grains. The machine was allowed to run empty for five minutes before the experiment commenced. Three samples of 1kg each were weighed and wetted with same quantity of water for 10, 20, and 30 minutes, respectively. The samples were then fed into the developed decorticator running at a speed of 420 rpm, and the operating speed and time taken were determined using a digital tachometer and stop watch, respectively. Samples of decorticated, undecorticated, and broken cowpea were collected and weighed to evaluate the efficiency of the machine based on the decorticating length and wetting time of cowpea grains. Results: The study revealed that as the decorticating length increased from 44.5 to 178 mm and wetting time increased from 10 to 30 minutes, the decorticating efficiency increased from 55 to Original Research Article

Energy Conversion and Management

INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET), 2021

Sawmills are workshops where woods are turned into finished products through the use of industria... more Sawmills are workshops where woods are turned into finished products through the use of industrial machines and sophisticated implements. However, sawmills workers become exposed to awkward working postures and vibration from the machines they work with every day, leading to Raynaud's disease and muscle damage. Therefore, this study investigated the effects of the sawmill-machine-generated vibrations on the musculoskeletal disorders of sawmill workers in the Southwestern part of Nigeria using hand-arm-vibration analysis. Sawmills that were fully functional in Osun, Oyo, Ondo, Ekiti, Lagos, and the Ogun States of the Southwestern part of Nigeria were used for this study. After reconnaissance visits, four sawmills operating at full capacities in two cities of each State (i.e. 2 sawmills per city) were eventually chosen and used for data collection, thereby making a total of 24 selected sawmills. Circular Machines (CMs), Planer Machines (PMs), and Band-saw Machines (BMs) which are the commonly used machines by sawmills were considered for analysis, Vibration Exposure Assessment of Sawmilling Operations using Hand-ARM-Vibration Exposure Analysis

International Journal of Emerging Trends in Engineering Research, 2020

The study employed an additive manufacturing approach to model the parts of a pilot-scale electri... more The study employed an additive manufacturing approach to model the parts of a pilot-scale electric car. A 3D Sketchup tool was used to model the parts of the model electric automobile and was printed using Any cubic i3 Mega 3D printer. A robust design analysis was carried out to determine the necessary parameters required for the motion and stability of the automobile. These include friction, thrusts and aerodynamic forces as well as the power required. The 3D printed parts were then assembled using powerful adhesives. The rechargeable battery-powered car was integrated with a "C" programming language with the aid of ATMEGA 328P-PUmicrocontroller. The results of the performance assessment of the automobile show that the car travelled at the rate of 1 m/s under the monitoring signal receiving a range of 3 m as observed from the infrared remote control. The results obtained from the design calculation indicated that a 3.975 Nm magnitude of torque is required to drive the shaft. Thus, it was possible to achieve an optimal performance since a motor of 10.787 Nm torque specification was used. The study demonstrates the feasibility of indigenous development of emerging autonomous electric cars at a lower cost.

International Journal of Advanced Trends in Computer Science and Engineering, 2020

Pulse-Electric Field (PEF) System can be described as a system that utilises high voltages applie... more Pulse-Electric Field (PEF) System can be described as a system that utilises high voltages applied at a specific interval and with a particular wave shape in treatment (inactivation and destruction of microorganism cells) of liquid or solid food. Pulse-Electric Field food processing system reduces the drawbacks (such as deterioration in sensory values, energy contents, and freshness) of other methods significantly. To generate the high voltage needed for the treatment, a series of capacitors and diodes connected were used. Generation of the desired pulse shape, which is the square wave is achieved through ATmega-328 microcontroller. The pulse control system is made up of a button to vary the treatment time, the power switch and a 16x2 alphanumeric Liquid Crystal Display (LCD) which serves as visual feedback. For the evaluation of the fabricated system, bacteria were cultured using MacConkey agar solution and then diluted in orange juice which serves as samples of liquid food. From the samples prepared, the bacteria count is in order of 1.61x10 5 CFU/mL before treatment, after treatment the count reduced to 1.01 x10 5 CFU/mL and 2.10 x10 4 CFU/mL concerning 1kHz and 2kHz pulse frequency used for the two samples treated.

International Journal of Advanced Trends in Computer Science and Engineering (IJATCSE), 2020

This paper takes a sincere attempt to enable advanced research in electric furnace simulation in ... more This paper takes a sincere attempt to enable advanced research in electric furnace simulation in order to determine thermal conductivity. A simple model was adopted for determining the thermal conductivities of brass, aluminium and copper materials using a system designed, constructed and tested and applying steady state method. C-Sharp program was developed using the standard subroutines to solve the model equations in order to predict the thermal conductivity over a wide range of temperature and process conditions. The furnace was demarcated into heating chamber (made by sandwiching heating coil within thermal insulators), sample holder region and the cold end area. The thermal conductivities of copper, aluminium, and brass were measured using the system and the results obtained were compared statistically with other standards. It was observed that the measured thermal conductivity values were 112.9, 244.4 and 403.2 Wm-1 K-1 for brass, aluminium and copper respectively. These results compared relatively well with other standard values. Such values are in order 109, 236 and 396 Wm-1 K-1 .

Journal of Energy Technologies and Policy, 2013

Globally, 140 billion metric tons of biomass is generated every year from agriculture. This volum... more Globally, 140 billion metric tons of biomass is generated every year from agriculture. This volume of biomass can be converted to an enormous amount of energy and raw materials. These residues are usually dumped and flared on the farms, where they constitute health risk to both human and ecology. Densification of these residues would improve their bulk handling, transportation and storage properties. Therefore, this work investigated densification characteristics of cassava and yam peels using an experimental briquetting machine. The ASAE standard methods were used to determine the moisture contents (dry basis) and densities of the milled residues and briquettes, while ASTM standard methods were used to determine the proximate and ultimate analyses of the residues. The initial, maximum and relaxed densities were also determined using ASAE standard methods. Also evaluated were compaction, density and relaxation ratios of the briquettes. The mechanical properties were determined using universal testing machine, while the heating value was determined using Ballistic Bomb calorimeter. The mean moisture contents of cassava and yam peels residues were 10.19% and 9.27% respectively, while those of relaxed briquettes were 8.76% and 7.95% respectively. The initial, maximum and relaxed densities were 251.50 kg/m 3 ; 741.13 kg/m 3 and 386.4 kg/m 3 respectively for briquettes produced from cassava peel, while the corresponding values for briquettes produced from yam peel were 283.40 kg/m 3 ; 911.45 kg/m 3 and 512.54 kg/m 3 respectively. The compaction ratio of 2.94 and 3.21 were obtained for briquettes produced from cassava and yam peels respectively. The compressive strength of briquette from cassava peel was 1.53kN/m 2 (SD 0.05), while that of yam peel was 1.76kN/m 2 (SD 0.04). The higher heating value of briquettes from cassava peel was found to be 12,765kJ/kg (SD 30), while the corresponding value for yam peel was 17,348kJ/kg (SD 20). The results of this work indicate that briquettes produced from the two biomass residues would make good biomass fuels. However, findings show that yam peel briquette has more positive attributes of biomass fuel than its cassava peel counterpart. It has a moderate moisture content of 10.95 %, higher density of 911.45 kg/m 3 and lower relaxation ratio of 1.78. Other positive attributes of yam peel briquette over cassava peel are long after glow time of 375 secs and slow propagation rate of 0.16 cm/s. It also has higher heating value of 17,348 kJ/kg and compressive strength of 1.76 kN/m 2 compared to cassava peel, which are 12,765 kJ/kg and 1.53 kN/m 2 respectively.

The comfortable mattress is said to be an essential ingredient in a good night sleep, but we have... more The comfortable mattress is said to be an essential ingredient in a good night sleep, but we have little understanding of the desirable properties (especially, the mechanical properties) of a quality mattress and as a result, when allowed to test mattresses in a typical showroom, individuals choose a mattress that does not minimize overnight motion and maximize perceived sleep quality. Many of the symptoms people suffer from are being caused, in part; by the way they sit, stand and sleep. In order to have a good understanding of how to choose the appropriate mattress, both for seating or bending application, which will help solve these problems, a vibrant knowledge of the major indicator of mattress quality is of paramount importance and this is the purpose of this research work. A series of laboratory tests were carried out on four samples of flexible polyurethane foams of zero, four, seven and fourteen years of usages and of different manufacturers (to allow for variation of density) to determine the relationship between the foam's overall density and other mechanical properties of the foams such as the support factor, compression modulus, resilience, tensile strength, etc , all of which are the major indicators of the quality and performance of any flexible polyurethane foam. The results obtained for these laboratory tests showed significant variation in the values of support factor, compressibility modulus, resilience, tensile strength, percentage elongation and hardness factor with respect to variation in the foams' densities. These factors improve as the foam's density increases, except for the compression set and hardness factor which were found to decrease, indicating they are not function of foam's density. A study of the trend of variation of these factors with density shows that the major determinant factor of flexible polyurethane foam's quality is its density and not necessarily its age.