Papers by Bukola O Bolaji
FUOYE Journal of Engineering and Technology, Dec 29, 2023
The global need for blood product safety and availability in emergencies far outstrips supply, th... more The global need for blood product safety and availability in emergencies far outstrips supply, thus attracting the attention of both academia and industry for more technological advancement. The paper examined cascade refrigeration system applications for efficient blood plasma management in energy-deficient communities. Fresh animal plasma was utilised to evaluate the system's performance for the tests of feasibility, reliability, and reproducibility due to some ethical considerations in collecting human blood samples by non-medical personnel. The plasma machine was used to compare two convectional freezers at -35 °C. The system was analysed at different loading conditions for refrigerating effects and storage time. Pre- and post-plasma protein tests for integrity were carried out
FUOYE Journal of Engineering and Technology, Oct 1, 2023
Daily life-saving transfusions rely on the usage of blood products in clinical and research setti... more Daily life-saving transfusions rely on the usage of blood products in clinical and research settings. With its proteins used for replacement treatment, human blood plasma serves as the main source for a variety of therapeutic transfusions. During the COVID-19 pandemic, plasma-based therapy was one of the treatment modalities used to treat infectious infections and as a source of neutralizing antibodies in patients. The speciality of transfusion medicine was adversely impacted and faced a stockpile shortage because plasma must be quickly frozen within six hours of collection in order for its proteins and coagulation components to be of the optimum quality. As a result, the cascade refrigeration system is an innovative technology that can provide the required ultra-low freezing temperature and maintain the same temperature in storage for plasma management. The paper concentrated on the design and construction analysis of a two-stage cascade refrigeration system for quick freezing time, and storing plasma proteins at extremely low temperatures to prolong their limited shelf life in a sensitive, temperature-controlled storage system. The choice of refrigerants R404A and R410A is made for high temperature and low temperature circuits which are carefully selected based on study and analysis of the characteristics of different refrigerants for short-term freezing. The ultra-low temperature evaporator is achieved using a blend of two vapour compression refrigeration cycles thermally connected by a heat exchanger to produce a freezing temperature of -35 0 C. For analysis, the system was charged with various weights of plasma weighing between 1 kg and 4 kg for two hours and a half hour and kept at a temperature of -35 0 C. The system's dependability and practicality for extending plasma shelf life were assessed. After 72 hours of temperature-controlled storage, the results showed 75% efficiency and a negligible (0.4) plasma quality drop.
ABUAD Journal of Engineering Research and Development, Mar 31, 2024
This paper focused on the characterization of oils and biodiesels derived from Ackee apple seeds ... more This paper focused on the characterization of oils and biodiesels derived from Ackee apple seeds and African star apple seeds obtained from local markets. The oils from individual seeds and their mixtures at varying ratios were characterised for relative density, free fatty acid, acid, iodine, and saponification, which yielded 0.91 g/cm 3 , 1.06 mg-KOH/g, 2.12 mg-KOH/g, 38.36mg-iodine/100g, and 195.74 mg-KOH/g of ackee seed oil, respectively. And 0.89 g/cm 3 , 2.105 mg-KOH/g, 4.2 mg-KOH/g, 52.49 mg-iodine/100 g, and 227.7 mg-KOH/g of African star apple seed oil, respectively. The highest relative density of 0.9064 g/cm 3 and free fatty acid of 3.73 mg-KOH/g were achieved from the mixture of ackee apple and African star apple seeds' oils at 80 and 20%, respectively, while the highest saponification of 221.264 mg-KOH/g and iodine of 49.66 mg-iodine/100 g were obtained from the oil mixture of 20 and 80%, respectively. Also, the oils extracted from the seeds, were subjected to a transesterification process to produce biodiesel. 144°C flash point, 206°C fire point, and 2.8°C cloud point were obtained from the biodiesel of the oil mixture of 20 and 80%, respectively. Further analysis of the mixtures showed low volatility and high resistance to fire due to their high flash and fire points. The highest value recorded for the flash point is lower when compared with some other seed oils flash points; however this value is higher than the standard flash point for biodiesels .Highest boiling point of 64°C was attained at an oil mixture ratio of 60 and 40%, respectively. This value is too low compared to the normal boiling point range of 315-350°C for biodiesels, and the high acid values recoded for the mixtures make the oils inedible. The oils, however, have advantages over other edible seed oils as they will serve as valuable ingredients in the soap-making industries since they are not competing with food resources.
Heliyon, Apr 1, 2024
This paper presents a workable vapour compression system (VCS) for evaluating the performance of ... more This paper presents a workable vapour compression system (VCS) for evaluating the performance of a refrigeration system with an integrated condenser that uses a long-term alternative refrigerant to halocarbon as a heat transfer medium (R600a). India's refrigeration system uses halocarbon refrigerants due to their excellent thermophysical and thermodynamic properties. Greenhouse gas emissions from halocarbon refrigerants and fossil fuel combustion contribute to global warming that engenders climate change and the deterioration of the ecosystem. The halocarbon refrigerant was discontinued based on high global warming potential. The system was investigated under various ambient temperatures of 16, 20, 24, and 28 • C (o C). The performance of the VCS was analyzed using the parameters of coefficient performance, compressor work, and pull-down time (PDT). The experimental result shows that the vapour compression system obtained its best PDT, enhanced coefficient of performance, and energy reduction when the ambient temperature was 20 • C.
Sigurnost, Jan 2, 2024
Liquefied petroleum gas (LPG), like other hydrocarbon gases, has good thermo-physical and ecologi... more Liquefied petroleum gas (LPG), like other hydrocarbon gases, has good thermo-physical and ecological properties, but its high-flammability has limited its direct use in refrigeration applications. Therefore, this paper investigates the thermodynamic performance of low flammable and ecological-save mixtures of LPG and tetrafluoroethane refrigerant in a refrigeration system. The computational results of global warming potential (GWP) and low flammability limit shown that the blends with 50-90 % LPG contents have GWP below 750 and fall within the lower flammability safety class of which five were selected for further analysis. The results showed that the thermal conductivity and the refrigerating effects produced by the selected blends are greater than those of the reference refrigerant (R134a). Also, the selected blends exhibited appropriate lower pressure ratio, discharge temperature and specific power than R134a refrigerant. Four of the blends required low power input and exhibited higher coefficient of performance which are clear indication that they are more energy efficient than R134a in the refrigeration systems.
The holistic approach to environment, Sep 14, 2023
The use of refrigerants with a global warming potential (GWP) greater than 150 is banned in small... more The use of refrigerants with a global warming potential (GWP) greater than 150 is banned in small and medium-sized refrigerators in accordance with the European F-Gas policy. Therefore, the suitability of retrofitting an existing refrigerator using a low GWP working fluid (R152a), as a replacement for the usual refrigerant (R134a) that is harmful to the environment, was investigated experimentally in this paper. In this study, close trend and similarities have been observed between the retrofit refrigerant (R152a) and the traditional refrigerant (R134a) in terms of their thermophysical properties. This has shown the compatibility of R152a with the components of the existing refrigerator. The two refrigerants met the pull-down time standard for the refrigerator, but the values of R152a were consistently lower than those of R134a. In addition, R152a consumed less energy with higher coefficient of performance and cooling capacity (12.2 and 14.6 %, respectively) than R134a. Due to the superior performance and the eco-friendly properties of R152a, it is recommended as a retrofit refrigerant for the existing small and medium-sized refrigerators.
ABUAD Journal of Engineering Research and Development (AJERD), Dec 29, 2023
Brass Nanofluid is a substance made from synthetic copper and zinc powder. It has outstanding mec... more Brass Nanofluid is a substance made from synthetic copper and zinc powder. It has outstanding mechanical, electrical, thermal and optical qualities employed in a variety of applications including, solar, touch screen, bison. The nanoparticles used in this study were developed from brass alloy which was locally sourced and machined to the required nano-size of 40 µm. A top-down strategy was used for the preparation of nanofluid and ball milling utilized to ground the brass alloy and sieved after grinding using a 40 µm sleeve. A double approach strategy was applied to prepare the nanofluid and the sonification process of brass nanofluid was conducted using ultra sonic equipment. The result shows that the light paraffin oil with varying concentration percentage of brass alloy and conventional cutting fluid (castrole oil) with varying concentration percentage of brass alloy display similar performance. Optimizing the additive ratio of nano particle provided better outcomes identified in the range of 2-10g with 200 ml of cutting fluid. This improves the surface roughness finish of machined part while inclusion of brass nano particle with cutting fluid improves the material removal rate, reduce the temperature and the cutting zone providing a guaranteed finish product compared to other base fluid.
Current Journal of Applied Science and Technology
A cascade refrigeration cycle is a multistage refrigeration system for ultra-low freezing applica... more A cascade refrigeration cycle is a multistage refrigeration system for ultra-low freezing application utilizing two stage vapour compression refrigeration system. Many refrigeration applications require low temperature for quick freezing medical items, production of ice, petroleum vapour liquefaction, pharmaceutical products preservation and storage, and manufacturing cooling processes. The two-stage cascade refrigeration system is the simplest, energy efficient and low operating cost for providing deep-freezing and maintaining extremely low temperature stability. The paper presents the overview of two-stage cascade refrigeration system for ultra-low temperature application and considered vapour compression cycle the most viable and suitable technique of attaining designed and desired temperature application. System modification using different techniques such as pre cool, flash intercooler, dedicated mechanical subcooling cycle, and novel ternary mixture of refrigerants were method...
FUOYE Journal of Engineering and Technology, Oct 1, 2023
Daily life-saving transfusions rely on the usage of blood products in clinical and research setti... more Daily life-saving transfusions rely on the usage of blood products in clinical and research settings. With its proteins used for replacement treatment, human blood plasma serves as the main source for a variety of therapeutic transfusions. During the COVID-19 pandemic, plasma-based therapy was one of the treatment modalities used to treat infectious infections and as a source of neutralizing antibodies in patients. The speciality of transfusion medicine was adversely impacted and faced a stockpile shortage because plasma must be quickly frozen within six hours of collection in order for its proteins and coagulation components to be of the optimum quality. As a result, the cascade refrigeration system is an innovative technology that can provide the required ultra-low freezing temperature and maintain the same temperature in storage for plasma management. The paper concentrated on the design and construction analysis of a two-stage cascade refrigeration system for quick freezing time, and storing plasma proteins at extremely low temperatures to prolong their limited shelf life in a sensitive, temperature-controlled storage system. The choice of refrigerants R404A and R410A is made for high temperature and low temperature circuits which are carefully selected based on study and analysis of the characteristics of different refrigerants for short-term freezing. The ultra-low temperature evaporator is achieved using a blend of two vapour compression refrigeration cycles thermally connected by a heat exchanger to produce a freezing temperature of-35 0 C. For analysis, the system was charged with various weights of plasma weighing between 1 kg and 4 kg for two hours and a half hour and kept at a temperature of-35 0 C. The system's dependability and practicality for extending plasma shelf life were assessed. After 72 hours of temperature-controlled storage, the results showed 75% efficiency and a negligible (0.4) plasma quality drop.
Current Journal of Applied Science and Technology
A cascade refrigeration cycle is a multistage refrigeration system for ultra-low freezing applica... more A cascade refrigeration cycle is a multistage refrigeration system for ultra-low freezing application utilizing two stage vapour compression refrigeration system. Many refrigeration applications require low temperature for quick freezing medical items, production of ice, petroleum vapour liquefaction, pharmaceutical products preservation and storage, and manufacturing cooling processes. The two-stage cascade refrigeration system is the simplest, energy efficient and low operating cost for providing deep-freezing and maintaining extremely low temperature stability. The paper presents the overview of two-stage cascade refrigeration system for ultra-low temperature application and considered vapour compression cycle the most viable and suitable technique of attaining designed and desired temperature application. System modification using different techniques such as pre cool, flash intercooler, dedicated mechanical subcooling cycle, and novel ternary mixture of refrigerants were method...
Adeleke University Journal of Engineering and Technology, 2023
The global need for blood product safety and availability in emergencies far outstrips supply, th... more The global need for blood product safety and availability in emergencies far outstrips supply, thus attracting the attention of both academia and industry for more technological advancement. The paper examined cascade refrigeration system applications for efficient blood plasma management in energy-deficient communities. Fresh animal plasma was utilised to evaluate the system's performance for the tests of feasibility, reliability, and reproducibility due to some ethical considerations in collecting human blood samples by non-medical personnel. The plasma machine was used to compare two convectional freezers at -35 °C. The system was analysed at different loading conditions for refrigerating effects and storage time. Pre- and post-plasma protein tests for integrity were carried out
The study of fluid flow phenomenon is a very important one in the education of engineering studen... more The study of fluid flow phenomenon is a very important one in the education of engineering students and one of the equipment that can help in doing this is the forced vortex equipment. This equipment has been designed and constructed to verify the turbulent flow caused by fluid rotation at constant angular velocity. Results obtained showed a parabolic profile of liquid surface in the equipment, which confirmed the type of equation of pressure head normally developed in a forced vortex. The Reynolds number obtained at the flow between minimum and maximum speeds of the impeller (268949 and 462256 respectively) were much greater than 4000 above which flow is turbulent, which also confirmed the turbulence of forced vortex flow. Performance test with the equipment also indicates its average efficiency of 99.18 % as analytical values of pressure head at maximum impeller speed deviated from the experimental values only in the range 0.63 to 1.27 % and at minimum impeller speed, deviation is in the range 0.27 to 1.37 %.
Energy & Environment, Dec 1, 2012
In this study, a mobile, indirect passive solar drying system was designed and constructed on the... more In this study, a mobile, indirect passive solar drying system was designed and constructed on the principles of convective heat flow using locally sourced materials to dry cassava chips. The performance of the dryer was evaluated and the results obtained showed that the system is to a large extent effective in dehydrating food items reasonably and rapidly to a save moisture level. The maximum temperatures obtained in the collector, lower and upper parts of the drying chamber were 78.5, 71.0 and 68.5 o C, respectively during the validation test at noload operating condition, while maximum temperature of 71.0, 62.5 and 60.0 o C, respectively were obtained during the dehydration test. The maximum ambient air temperature was 33.5 o C. The dryer was able to reduce the moisture content of 500 g cassava chips from 74.5 to 20.3% (dry basis) in 6 hours of effective dehydration time. The system overall thermal efficiency and average drying rate were found to be 58.4% and 0.083 kg/h, respectively.
FUOYE Journal of Engineering and Technology, Dec 17, 2022
Composite material is made up of at least two distinct materials functioning together to provide ... more Composite material is made up of at least two distinct materials functioning together to provide material properties that are different and unique to their own, with quality superior than its constituents. Generally, metal matrix composite materials consist of a matrix (bulk material) and a reinforcement of some type, which are combined primarily to enhance the strength and stiffness of the matrix. Metal matrix composites combine the metallic properties of matrix alloys with the ceramic properties of reinforcements, to develop materials with greater strength capabilities. They are materials that are attractive and suitable for a large variety of engineering applications. This work reviews the effects of silicon carbide particulate reinforcements on aluminium metal matrix composites for marine and underwater applications, with specific emphasizes on improved mechanical, structural and corrosion properties. In this paper, specific reference was given to stir casting techniques as a liquid state metal manufacturing method of aluminium metal matrix composites. The work revealed that silicon carbide significantly enhances the overall mechanical and tribological strength of the composite along with corrosion resistance. It was revealed that research efforts have mostly been focused on the mechanical, physical and thermo-mechanical characteristics of the composites, more recourse to their corrosion characteristics is very significant in evaluating its application potential as marine structural materials.
Journal of the University of Science and Technology, Sep 8, 2005
FUOYE Journal of Engineering and Technology
— Hand washing has become a new normal in our society to prevent the spread of COVID-19 and other... more — Hand washing has become a new normal in our society to prevent the spread of COVID-19 and other viruses. As a result of the need to comply with World Health Organization (WHO) guidelines on hand washing to reduce the risk of infection transmission, an automated hand washing system with an installed water recycling device was developed. The integration of recycling water ensures effective energy resource management and reduces environmental pollution. The conceptual architectural design of the automated hand washing machine was established using AutoCAD software and the Arduino microcontroller panel. The operation of the hand washing systems consists of assembling relevant sensors to automate the liquid soap, water, hand dryer and sanitiser dispenser. A filtration reactor was used to convert the wastewater to clean water. The clean water is then pumped to the overhead tank by a submersible pump inside the lower tank for reuse. The water treatment was achieved by adding 5g of aqueous and into 1000g of used water. The water samples were then analysed in the laboratory to ascertain their purity, and results were obtained. The purification of the recycled water ranges from 82% to 83%, and the salvage volume of the recovered clean water is 80%. The microcontroller was successful in coordinating the various activities of the automated system. The automatic washing machine will reduce water waste, eliminate environmental pollution and curb disease transmission.
FUOYE Journal of Engineering and Technology
In this paper, the mixture of CO2 and LPG is being investigated, and the salient properties of th... more In this paper, the mixture of CO2 and LPG is being investigated, and the salient properties of the refrigerants were the main pointer to the development of a mixed refrigerant. Since CO2 offers a much higher volumetric capacity, the problem of the higher working pressure can be overcome by mixing it with a lower pressure refrigerant. LPG on the other hand has a cooling capacity of about 10% higher than R12 and the vapour pressure is appropriate. It has excellent thermodynamic properties leading to high energy efficiency and operates at lower pressures than other main refrigerants while maintaining a similar volumetric refrigerating effect, but it is highly flammable. Therefore, by combining CO2 and LPG in the right amounts, we can create a blend that will have low pressure while also being less combustible, more effective at cooling than the old one, more energy-efficient, with an improved coefficient of performance (COP), and safer for the environment. The different studies examin...
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Papers by Bukola O Bolaji
when dealing with the relationships of fluid flow on an analytical or mathematical basis. The continuum hypothesis treats the fluid as being infinitely divisible without character change. Therefore, material properties like viscosity, density or thermal conductivity, and variables such as pressure, temperature and velocity, can be defined at a mathematical point as the limit of the mean of the given variable or quantity across
the molecular fluctuations.