FUOYE Journal of Engineering and Technology (FUOYEJET - Federal University Oye-Ekiti)
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287 research outputs found
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Effect of Elevated Temperatures on SAC305 Solder Alloy Thermal Interface Material in a Microelectronic Assembly
No full textIn microelectronics assemblies, Thermal Interface Materials (TIMs) are vital to the reliability of the devices in operation. Some electronic devices operate in elevated temperature environments such as military and industrial applications. Hence, the need to evaluate the reliability of such devices at elevated temperatures. Tin-Silver-Copper lead-free solder TIMs have been used during the assembly process of some electronic devices operating under harsh temperature environments. In this study, the reliability of SAC305 lead-free solder TIM was considered at elevated temperatures ranging from 100 oC to 200 oC at 25 oC interval, and aged for about an hour. ANSYS finite element analysis software was employed for the design and evaluation of SAC305 lead-free solder model. The findings of the investigation demonstrated that the higher the harsh temperature environment, the lower the reliability of the SAC305 solder TIM. In addition, the highest fatigue life (36735 or 4.2 years) was recorded at 100 oC, while 200 oC recorded the lowest fatigue life (1014 or 0.12 years). The fatigue life is an indication of the lifespan of the TIM when in operation. This research will be beneficial to engineers assembling microelectronic products. Keywords— elevated temperature; fatigue life; microelectronics; reliability; SAC305 solder
Empirical Assessment of Missing Link in Agricultural Technology Development and Transfer Nexus in Nigeria
No full textGovernments and Non-Governmental Organisation (NGOs) focussed on the funding of research but neglect a very crucial issue of the transfer of technologies. Unfortunately, most of these technologies invented end up on bookshelves which might be as a result of missing linkage between the researchers, extension organizations and farmers. Therefore, the study focussed on factors associated with the missing link among researchers, extension workers and farmers in technology development and transfer. The study was carried out in the south-western part of Nigeria. The study employed the use of an interview schedule for farmers and questionnaire for extension personnel and researchers. A simple random sampling technique was used to select 398 respondents which include 80 researchers, 85 extension agents and 233 farmers.Data collected were analysed with descriptive statistics and correlation coefficient. The findings revealed that most (61%) of the selected technologies developed by research institutions were not known to the farmers. About 21% out of 39% of farmers that were aware of the technologies were still using it while 18% had discontinued the usage. Factors associated with research-extension-farmers missing link include package of recommendations not suitable for farmers (researcher 95.7%, extension agents 84.3% and farmers 95.1%); time lag between the availability of research findings and their application by the farmer (research (64.2%) extension workers (73.2%) and farmers (80%)), wages and salary differential (researchers (65.4%) and extension workers (78.3%)) and inadequate funds (researcher 90.4% and extension workers (95.3%)). The linkage strength could be influenced by the personal and psychological factors of personnel involved in research and dissemination. The gap that exists between the technologies invented and those that have been accepted by farmers has to be bridged by developing stronger links between researchers, extension personnel and the farmers by government agencies. Keywords— Extension workers, farmers, linkage, researchers, research development, technology transfer
Design and Construction of a Low-Cost Automatic Single-Phase Transfer Switch
No full textIrregular power supply poses a serious problem in many developing countries with power outage usually experienced on a regular basis. Thus, this challenge necessitates the need for an automated method of power change over to an alternative source during power failure that will be an improvement over the manual change over system. This study aims to design and construct a microcontroller-based Automatic Transfer Switch (ATS) for a single-phase system. Atmega8 microcontroller was programmed to automatically switch power supply between a primary source and a secondary power source through the aid of relays. A modular approach was used in the design of this ATS, which incorporates Atmega8 microcontroller, diodes, resistors, L7805 voltage regulator, PC817 optocouplers, a buzzer alarm, NPN transistors, and a Liquid Crystal Display (LCD) that indicates which power source was available. This design is limited to 30A on full loading due to the power relay used in the design. The testing showed that the design was able to automatically switch power between two supply sources with no external aid and it performed optimally even when loaded to 90% of its maximum bearing-capacity.Keywords: Automatic Transfer Switch, Atmega8 Microcontroller, Liquid Crystal Display, NPN Transistors, PC817 Optocouplers, Relay
Adaptive Power Control with Selection Combiner over Nakagami-m Fading Channel
No full textAcceptable Quality of Service (QoS) is of paramount importance in wireless communication system. However, QoS is affected by multipath propagation resulting in unreliable reception. Selection Combiner (SC) which is one of the techniques previously used to solve this problem is associated with poor performance due to fixed power level used in the technique. Hence, in this paper, an Adaptive Power Control (APC) technique using SC with a closed form expression over Nakagami-m Fading Channel is proposed. APC technique is developed using fixed power SC and Link Adaptation Algorithm (LAA). Ten thousand (10,000) bits are randomly generated and modulated using Quadrature Amplitude Modulation (QAM) scheme. The modulated signal is passed through the Square Root Raised Cosine (SRRC) filter for suitable transmission over the Nakagami-m fading channel. The faded signals at varying paths ‘L’ (2, 3, 4) are selected by Conventional Selection Combining (CSC) to instruct the transmitter for adjustment of power level based on the value of the received signal through LAA. Mathematical expression for the received signal using Probability Density Function (PDF) of Nakagami-m Fading Channel at varying paths is derived. The APC technique is simulated using MATLAB software and evaluated using Signal to Noise Ratio (SNR), Outage Probability (OP) and Bit Error Rate (BER) to determine the performance of the proposed technique. OP values of 0.0969 and 0.1069 are obtained for APC and CSC, respectively, at SNR of 6 dB with L of 4, while BER values of 0.0052 and 0.2599 are obtained for APC and CSC, respectively. The percentage reduction in OP and BER are 29.79% and 54.43%, respectively. The results obtained show that APC gives lower OP and BER values with increase in SNR when compared with fixed power SC due to self-adjustment of the allocated power. Therefore, the APC technique proposed can be used to enhance the performance of wireless communication systems. Keywords— Adaptive Power Control (APC), Selection Combiner (SC), Link Adaptation Algorithm (LAA), Bit Error Rate (BER), Outage Probability (OP), Probability Density Function (PDF) and Diversity Combiner (DC)
Effect of Clusters in Energy-Efficient Cooperative White Space Detection in a Cognitive Radio System
No full textWhite Space Detection (WSD) is a core operation in a Cognitive Radio System (CRS) to identify idle spectrum for maximum utilization. However, WSD is often affected by multipath effects resulting in poor detection rate. Cooperative WSD (CWSD) which is one of the existing techniques used to address the problem is characterized by long sensing time, energy and bandwidth inefficiency. Energy-Efficient CWSD (EECWSD) was proposed in previous work to solve the problem associated with CWSD. Hence, in this paper, the effect of clusters in EECWSD is carried out with Radiometry Detector (RD). The investigation is carried out using multiple clusters and each cluster contained multiple Secondary Users (SUs). The SUs are used to perform local sensing and the sensing results are combined at individual cluster using majority fusion rule. The sensing results from individual cluster are combined to obtain global sensing result using OR fusion rule. The system is simulated using MATLAB software. The system is evaluated using Probability of Detection (PD), Total Error Probability (TEP), Spectral Efficiency (SE) and Sensing Time (ST). At SNR of 20 dB, PD values of 0.7890, 0.8376 and 0.8787 are obtained for clusters 3, 4 and 5, respectively, while the corresponding TEP values are 0.2210, 0.1724 and 0.1313 for clusters 3, 4 and 5, respectively. At SNR of 16 dB, 13.2594 and 16.4341 are the SE values obtained for clusters 3 and 5, respectively, while the corresponding ST values obtained are 4.2487 and 2.6177 s for clusters 3 and 5, respectively. The results obtained revealed that, PD and SE increase as number of cluster increases, while ST and TEP reduce as cluster increases. Keywords— Cognitive Radio, White Space, Spectrum Sensing, Probability of Detection, Spectral Efficiency
Characterization of Gosa Municipal Solid Wastes at Abuja, Nigeria
No full textThe study examined municipal solid wastes characteristics of Gosa dumpsite at Abuja, Nigeria. Waste characterization has not yet been given adequate attention in management of waste in Nigeria and it is a major problem that affects waste materials handling and recovery processes. Wastes samples from Gosa waste dump site, Abuja, were randomly collected and subjected to moisture content, composition, density and size distribution determinations according to prescribed standards in literature. The moisture content of the Gosa waste solid was 19.3%. The results of the characterization of the Gosa municipal solid wastes show 34% organic, 10% paper, 28% plastic, 2% glass, 6% metal, 4% fabric, 2% rubber and 14% dust. The average density of glass, metal, plastic, fabric, rubber, paper, organic and dust materials were 0.044 kg/m3, 0.045 kg/m3, 0.176 kg/m3, 0.043 kg/m3, 0.042 kg/m3, 0.074 kg/m3, 0.143 kg/m3 and 0.098 kg/m3, respectively. The size distribution of the Gosa solid waste ranges from 10-28 cm for metals and plastics and 3-13 cm for paper and glass. The rubber had size ranges from 8-23 cm while size ranges of organic was from 3-6 cm. The large presence of organic, plastic, paper and metal wastes at Gosa waste dump site, is an indication that the municipal solid wastes can be sorted, recycled and processed to other useful products, using the characteristics as a guide.Keyword: Characterization, Density, Municipal Solid Waste, Size Distribution, Waste Managemen
Effect of Pretreating Poultry Wastes with Cocoa Pod Husk Ash and Cassava Peel Ash on Biogas Production
No full textThe effect of addition of cocoa pod husk ash and cassava peel ash on biogas production from poultry waste was investigated. Three metallic floating drum digesters each of 36.5 L capacity and labeled A, B, and C were used. Digester A contained poultry waste only, B contained poultry waste blended with cocoa pod husk ash and C contained poultry waste blended with cassava peel ash. Biodigestion of the wastes in the three digesters was carried out simultaneously using a retention period of 41 days. The mass of poultry waste used in each of the three digesters was 20700 g. The biogas yield results showed that 13,977 cm3 of gas was produced in digester A, while 19,517 and 21,305 cm3 were produced in B and C respectively. When compare with digester A (control), addition of cocoa pod ash and cassava peel ash had increased biogas production by 39.63 and 52.43% respectively.Keywords— Cocoa pod husk, cassava peel, biogas, floating drum, digester, poultry wast
An Improved Vehicle Registration and Licensing System
No full textVehicle registration and licensing systems have been in existence for decades. However, there has been over 55% increase in the number of reported stolen vehicles which have not been recovered in the last 3 years. Therefore, there is need to improve on its existing systems by incorporating anti-theft capability of vehicles using fingerprint biometric technology. In developing the Secured Vehicle Registration System (SVRS), data on vehicle registration, renewal and change of ownership procedures were collected from the Motor Licensing Office at Osogbo. Unified Modelling Language (UML) tools was used for the system design, to illustrate the whole system in a clearer way, and implemented using JavaScript, PHP scripting language, HTML, XAMPP SQLServer and the Mantra MFS100 fingerprint scanner. The system performance was evaluated by authenticating registered vehicle owner biometric to calculate the Accuracy, Average Response Time (ART) and Apdex Score. The result of the evaluation using 288 fingerprint templates of 72 vehicle owners shows the False Accept Rate (FAR) of 0.0% and False Reject Rate (FRR) of 2.1%, which is equivalent to a system accuracy of 97.9%. The ART for the fingerprint execution matching is 36.3 microseconds while the overall system satisfaction Apdex score recorded was 0.73, which denotes a satisfying system. The high-speed verification method uses the lowest computational power and execution time to deliver accurate results through making a match or non-match against stored templates. The developed system demonstrated its ability to link vehicle(s) to its respective owner(s) and also function as an automatic identity verification system for vehicle owners using VIN and fingerprint. The system has the ability to be employed for preventing fraudulent change of ownership and also help reduce delay in processing vehicle license.Keywords— authentication, biometrics, database, fraudulent, information protection, motor vehicle administration, motor vehicle registry, security code, vehicle owner
The Development and Characterisation of Recycled Polyethylene Reinforced Particulate Cockle Shell for Automobile Application
No full textPolymer reinforced composites were developed from recycled polyethylene briquettes (matrix) and particulate cockle shells (reinforcement) via compounding and compression moulding technique. The objective was to use urban wastes to produce low-cost material for engineering applications as an alternative to their disposal by incineration, which can cause atmospheric pollution. The composites were characterized for wear test using spin on disk, XRD, Universal Testing Machine for Mechanical Properties and Scanning Electron Microscopy (SEM) for microstructure. Results obtained were compared with the unreinforced polymer, the composites exhibited higher tensile strength and impact energy, while the hardness reduced. More so, above 20% filler addition, the flexural strength and Young Modulus decreased. The composite can be used where rigidity is a crucial performance requirement; at 20% weight cockle shell, the composites can be used for car inner door opener where rigidity is required, while at 50% additions, the developed composite will be suitable for use in car interior dashboard where strength and fracture toughness are the most crucial property demand. Furthermore, the morphological study of the RPE/CSP composite showed a high homogeneous polymer matrix’s cockle shell particle blend. In conclusion, the study has established that particulate cockle shell waste and recycled polyethylene are suitable materials to produce polymeric composite. This is a novel material development from waste to wealth for environmental sustainabilityKeywords— Cockle shells, Recycled Polyethylene, Composite, Particulat
An Improved Data-Driven Model for the Prediction of Minimum Transport Condition for Sand Transport in Multiphase Flow Systems
No full textThe correct prediction of minimum transport condition (MTC) is of great importance to the oil and gas industry. The sand deposition is an associated problem of multiphase transportation of oil, gas and or solid. The purpose of this work is to investigate the predictive capability of three different data-driven approaches: Artificial neural networks (ANN), Adaptive neuro-fuzzy inference system or adaptive network-based fuzzy inference system (ANFIS) and response surface methodologies (RSM). The models were developed using182 experimental data points with input parameters such as liquid superficial velocity, pipe diameter, particle size, pipe inclination and the output parameter predicted is the minimum transport condition (velocity) for sand particles. The developed models were compared with existing models. The results showed that the three methods performed creditably well in the prediction of MTC with ANFIS having the highest predictive capability with an R2 value of 0.99997 and an average error value of 0.00035836 compared with ANN and RSM having R2 value of 0.9998 and 0.9973 respectively. The three data-driven techniques investigated in this study also outperformed published correlations for the prediction of MTC. The findings from this research can be invaluable for the effective and robust management of sand transport in multiphase flow systems.Keywords— Artificial Intelligence, Fuzzy Inference System, Model, Minimum Transport Condition, Optimization methods, Response Surface Methodolog