http://repository.fuoye.edu.ng:80/handle/123456789/31 2026-04-16T06:29:23Z 2026-04-16T06:29:23Z Bolaji, Bukola Olaleken http://repository.fuoye.edu.ng:80/handle/123456789/1426 2017-07-01T22:14:41Z 2017-06-28T00:00:00Z

Title: Dye-modified ZnO nanohybrids: optical properties of the potential solar cell nanocomposites Authors: Bolaji, Bukola Olaleken Abstract: We report the hybridization of ZnO with natural dyes [Laali, Zobo] or synthetic dye [methyl red] forming ZnO – laali, ZnO – zobo and ZnO – methyl red nanocomposites in bright colours. The structural, optical and dye photosensitization influence of the hybrid nanocomposites were studied by X – ray diffraction (XRD), scanning electron microscope (SEM), UV – visible absorption spectroscopy and photoluminescence (PL). The surface plasmon absorption band of ZnO – laali and ZnO – zobo shifts towards red and blue respectively, with significantly enhanced absorption intensities, indicating the interaction and optical influence of the respective dyes in photosensitization. Optical and absorption character of ZnO methyl red and bare ZnO are similar indicating insignificant effect of methyl red on photosensitization. PL spectra of ZnO – laali and ZnO – zobo display enhanced UV light emission due not only to the surface electron transfer from their respective inherent isoplumbagin and anthocyanin to ZnO but also to the extension of the Fermi energy level to the ZnO. Dyes adopted have influence on the optical band gaps of the evolved hybrid nanocomposites

2017-06-28T00:00:00Z Bolaji, Bukola Olaleken Oyelaran, Olatunde Ajani Okoye, Obinna Chibuzor http://repository.fuoye.edu.ng:80/handle/123456789/1425 2017-07-01T22:18:42Z 2017-06-30T00:00:00Z

Title: Thermodynamic Study of Environment-Friendly R429A, R435A and R457A Refrigerants as Substitutes for Ozone Depleting R22 in Refrigeration and Air-Conditioning Systems Authors: Bolaji, Bukola Olaleken; Oyelaran, Olatunde Ajani; Okoye, Obinna Chibuzor Abstract: Ozone depletion and global warming are presently the most serious global environmental problems and they have led to drastic changes in the refrigeration technology. Therefore, environment-friendly refrigerants have attracted a significant attention. This paper presents the thermodynamic study of non-ozone depleting R429A, R435A and R457A refrigerants as substitutes for R22 in air-conditioning systems. The results obtained showed that the vapour pressure curves of R429A, R435A and R457A are very close to that of R22 with advantage of lower deviation in pressure. These refrigerants also exhibited low pressure ratio and discharge pressure than R22 and their average discharge temperatures are 24.03, 13.54 and 28.53 % respectively lower than that of R22. They showed higher coefficient of performance than R22 with the average values of 2.47, 3.96 and 2.98 % respectively higher which shows better efficiency. The results also revealed R429A, R435A and R457A as energy efficient refrigerants as they exhibited lower power consumption per ton of refrigeration with average values of 2.14, 3.90 and 2.27 % respectively lower than that of R22. Generally, the three investigated environment-friendly refrigerants performed better than R22 and can effectively replace R22 in air-conditioning systems

2017-06-30T00:00:00Z Bolaji, Bukola Olaleken Huan, Z http://repository.fuoye.edu.ng:80/handle/123456789/1420 2017-04-06T21:12:53Z 2012-01-01T00:00:00Z

Title: Energy Performance of Eco-Friendly RE170 and R510A Refrigerants as Alternatives to R134a in Vapour Compression Refrigeration System Authors: Bolaji, Bukola Olaleken; Huan, Z Abstract: Ozone depletion and the atmospheric greenhouse effect due to refrigerant emissions have led to drastic changes in the refrigeration and air-conditioning technology. For this reason, environmentally benign, ‘natural’ refrigerants have attracted a considerable attention. In the group of natural refrigerants, hydrocarbons are the most closely related to the HFCs with similar thermodynamic and transport properties, which make them suitable as substitute refrigerants in the existing HFC systems without any major changes in the design. In this paper, the energy performance of two eco-friendly hydrocarbon refrigerants (RE170 and R510A) with zero ozone depletion potential and negligible global warming potential in vapour compression refrigeration system is investigated theoretically under different operating conditions. The results obtained showed that RE170 and R510A have similar saturation vapour pressure characteristics and thermophysical properties with R134a. The Energy performance of both R510A and RE170 was better than that of R134a. The average COPs of R510A and RE170 are higher than that of R134a by 20.7 and 13.1%, respectively. The lowest discharge temperature and energy consumption, and highest COP of the system were obtained using R510A. Generally, R510A and RE170 performed better than R134a; their energy consumptions are 20.4 and 14.1% less than that of R134a, respectively. Therefore, they can be used as drop-in substitutes in the existing R134a refrigeration systems.

2012-01-01T00:00:00Z Owoyemi, T.J. Adejuyigbe, Samuel Babatope Bolaji, Bukola Olaleken Akinwale, A.T. http://repository.fuoye.edu.ng:80/handle/123456789/1419 2017-04-06T21:05:36Z 2012-01-01T00:00:00Z

Title: Simulation of Refrigeration System in a Food Processing Company: A Case of Nigeria Bottling Company Ikeja Authors: Owoyemi, T.J.; Adejuyigbe, Samuel Babatope; Bolaji, Bukola Olaleken; Akinwale, A.T. Abstract: A simulation software was developed for a single stage vapour compression cycle. A study which was carried out on an existing system and a mathematical analysis using the energy and mass balance principle was used to develop the simulation model for the system. At full capacity of the system, the simulation gave a result with an error of 4.3% and when a twenty four-hour real data was compared with simulated data from the software, it was found that there is no significant difference between real data and simulated data having a p-value of 6.22% at a significance level of 5%. Investigation of the effect of condensing temperature, evaporating temperature and compressor speed on other system properties gave trends which agree with experimental data from similar refrigeration system and this analysis was used to carry out an optimisation of the existing system.

2012-01-01T00:00:00Z Aiyedun, P.O. Igbudu, O.S. Bolaji, Bukola Olaleken http://repository.fuoye.edu.ng:80/handle/123456789/1418 2017-04-06T20:57:29Z 2008-01-01T00:00:00Z

Title: Simulation of Load during Rod Rolling of HCSS316 at Low Strain Rate Authors: Aiyedun, P.O.; Igbudu, O.S.; Bolaji, Bukola Olaleken Abstract: In this work, rolling loads of HCSS316 for seventeen sequential passes for the reduction of a 125 x 125 mm2 billet to a 16 mm diameter rod at four different starting mean temperatures of 9880C, 10940C, 10950C and 11910C and at different strain rates of 0.4s-1, 0.8s-1, 1.2 s-1 and 1.6 s-1 respectively, were simulated using the “Phantom Roll” method for Carbon-Manganese steel. In general, it was observed that load value increased as starting temperature decreases and for each set of starting temperatures, the load value increases with temperature. In all cases, the load values for grooved rolls were higher than those for flat rolls.

2008-01-01T00:00:00Z Akinola, O.A. Bolaji, Bukola Olalekan http://repository.fuoye.edu.ng:80/handle/123456789/1417 2017-04-06T20:49:59Z 2006-01-01T00:00:00Z

Title: Sustainable Energy Technologies for Poverty Alleviation and Environmental Protection Authors: Akinola, O.A.; Bolaji, Bukola Olalekan Abstract: This paper examines the importance of sustainable energy technologies in addressing poverty eradication and environmental protection. The paper reveals the failure of conventional energy strategies in meeting the basic human needs of the poor majority. People living in poverty have benefited very little from conventional energy policies and their implementation. The lack of available energy services correlate closely with many poverty indicators. The use of unsustainable energy technologies has negative environmental effects and the people with low income are the most vulnerable. Limited income forced households to use traditional fuels and inefficient technologies. Various policies and measures that can improve the level of energy services for people living in poverty are discussed. Providing energy services to rural areas offers considerable opportunity for improving the lives of billions of people within a relatively short period. Promising approaches include decentralized rural electrification, appropriate technologies, modernized biomass and improved cookstove designs.

2006-01-01T00:00:00Z Bolaji, Bukola Olaleken http://repository.fuoye.edu.ng:80/handle/123456789/1416 2017-04-06T20:35:56Z 2005-01-01T00:00:00Z

Title: Performance Evaluation of a Simple Solar Dryer for Food Preservation Authors: Bolaji, Bukola Olaleken Abstract: This paper presents the design, construction and testing of a simple solar dryer for food preservation. Its construction was accomplished using mainly inexpensive locally available materials to make it relatively affordable to the average poor farmer dwelling in the rural area. The dryer temperature was found to be above the ambient temperature by an average of 51 % throughout the day-light time and the temperature rise was up to 75 % for about three hours immediately after 12.00 h (noon). The drying rate and the system efficiency were 0.46 kg/h and 59 % respectively. The rapid rate of drying in the dryer reveals its ability to dry food items reasonably rapidly to a safe moisture level and simultaneously it ensures a superior quality of the dried product. The results obtained indicate that solar dryers have a future especially in food preservation.

2005-01-01T00:00:00Z Adu, M. Rotimi Bolaji, Bukola Olalekan http://repository.fuoye.edu.ng:80/handle/123456789/1415 2017-04-06T20:40:23Z 2004-01-01T00:00:00Z

Title: Possibility of Rural Electrification through Solar Energy in Nigeria Authors: Adu, M. Rotimi; Bolaji, Bukola Olalekan Abstract: This paper presents the analysis of the possibility of employing solar energy for the supply of electricity to the rural communities in Nigeria. It describes various types of photovoltaic systems for rural electrification with more detailed discussion devoted to the domestic power supply, health care systems and lighting systems. It highlights the potentials of solar pumping systems in addressing the problems of lack of potable water and supply of water for irrigation in the rural areas.

2004-01-01T00:00:00Z Bolaji, Bukola Olaleken http://repository.fuoye.edu.ng:80/handle/123456789/1414 2017-04-06T20:23:46Z 2003-01-01T00:00:00Z

Title: The Role of Solar Energy in the Preservation of Agriculture Products in Nigeria Authors: Bolaji, Bukola Olaleken Abstract: The use of energy from renewable sources particularly from the sun is, and always has been, basic to farming. This paper presents the possibilities of tapping from the inexhaustible energy source for the preservation of agricultural products in order to accelerate the pace of industrialization and food production in Nigeria. Various ways in which solar cooling can be utilized in agricultural firms for the preservation of their products are discussed. Types of solar drying equipment and the necessity of using direct solar dryers as a consequence of disadvantages exhibited by the natural sun drying systems are explained.

2003-01-01T00:00:00Z Bolaji, Bukola Olaleken http://repository.fuoye.edu.ng:80/handle/123456789/1413 2017-04-06T20:15:12Z 2005-01-01T00:00:00Z

Title: CFC Refrigerants and Stratospheric Ozone: Past, Present and Future Authors: Bolaji, Bukola Olaleken Abstract: Scientists understanding of the interactions between ozone and the chlorofluorocarbon (CFC) refrigerants in the stratosphere have continued to increase since mid-1970s. This paper reviews the worldwide efforts to reduce the environmentally harmful effects of CFC refrigerants on the stratospheric ozone layer over the last 20 years. It examines the global environmental issues that catalysed recent changes in refrigeration industry. It discusses the effects of ozone depletion, the benefits of the CFC phase-out, the present and the future alternatives to CFC refrigerants.

2005-01-01T00:00:00Z Bolaji, Bukola Olaleken http://repository.fuoye.edu.ng:80/handle/123456789/1412 2017-04-06T20:09:25Z 2005-01-01T00:00:00Z

Title: Automobile Air Pollutant Emission and Control. In Environmental Sustainability and Conservation in Nigeria Authors: Bolaji, Bukola Olaleken Abstract: One major problem the populace, and indeed the people in the urban cities, are facing today is environmental pollution. This paper analyses various sources of pollutant emissions from the internal combustion engines. For proper determination of emission levels, the detailed chemical processes of pollutant formation with the methods of obtaining the specific emission and emission index were analysed. The paper also discusses how emission of pollutants from automobile can be controlled by incorporating catalytic converter and particulate traps in the exhaust system.

2005-01-01T00:00:00Z Waheed, M.A. Samuel, Olusegun David Bolaji, Bukola Olaleken Dairo, O.U. http://repository.fuoye.edu.ng:80/handle/123456789/1411 2017-04-06T20:02:45Z 2015-01-01T00:00:00Z

Title: RSM Optimization of Biodiesel Production from Tobacco Seed Oil Authors: Waheed, M.A.; Samuel, Olusegun David; Bolaji, Bukola Olaleken; Dairo, O.U. Abstract: Biodiesel is a monoalkyl ester of fatty acid of long chain derived from vegetable oil. Response surface methodology based on Central Composite Design is used to analyze the interaction effect and to optimize the transesterification reaction variables such as reaction duration, catalyst amount and oil to methanol ratio on biodiesel yield. A quadratic model developed based on the CCD, correlating the yield of biodiesel with reaction variables. The predicted yield by optimization is found very close to the experimental values. The optimum conditions for biodiesel production is found to be at the reaction duration of 78 min, oil to methanol ratio of 1:6.09 and catalyst amount of 1.13%. The fuel properties of tobacco methyl ester at the optimized parameters are determined as per ASTM standard and the results of the TSO biodiesel are within biodiesel specifications.

2015-01-01T00:00:00Z Adejuyigbe, Samuel Babatope Bolaji, Bukola Olalekan http://repository.fuoye.edu.ng:80/handle/123456789/1410 2017-04-06T19:39:05Z 2012-01-01T00:00:00Z

Title: Development and Performance Evaluation of a Rice De-Stoning Machine using Vibrating Sieves Authors: Adejuyigbe, Samuel Babatope; Bolaji, Bukola Olalekan Abstract: A rice de-stoning machine using vibrating sieves was designed, fabricated with locally sourced materials and tested. The performance of the machine was evaluated and the results obtained showed that the feed regulator opening has significant effects on the de-stoning rate, de-stoning efficiency and rice losses. The best performance was obtained at feed regulator opening of 20 mm. Above 20 mm opening, the higher the feed regulator opening the higher the de-stoning rate and grain losses, and the lower the de-stoning efficiency. The average capacity of the machine was found to be 31.84 g/sec. and the average efficiency also was 98.3%.

2012-01-01T00:00:00Z Bolaji, Bukola Olaleken http://repository.fuoye.edu.ng:80/handle/123456789/1409 2017-04-06T19:26:38Z 2011-01-01T00:00:00Z

Title: Selection of Environment-Friendly Refrigerants and the Current Alternatives in Vapour Compression Refrigeration Systems Authors: Bolaji, Bukola Olaleken Abstract: In this paper, the processes of selecting environment-friendly refrigerants that have zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP) were analysed. Various compositional groups of halocarbon refrigerants and their environmental problems were discussed. This paper also focuses on the refrigerants found on the matrix triangles of methane and ethane derivatives for the selection of appropriate environment-friendly refrigerants. Trade-offs in flammability, toxicity, chemical stability and atmospheric lifetime, and consideration of compounds without chlorine content, scaled down the refrigerants to R23 and R32 from methane derivatives and R152a, R143a, R134a and R125 from ethane derivatives. These refrigerants are recommended for further investigations to ascertain their suitability in vapour compression refrigeration systems. Alternative refrigerants that are currently employed in the systems were discussed. This revealed their areas of shortcomings which researchers must focus in order to make them acceptable worldwide

2011-01-01T00:00:00Z