Arid Zone Journal of Engineering, Technology and Environment (AZOJETE)
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Wind Energy Assessment in Auchi, Nigeria using Weibull Distribution and NASA Data
Get PDFThe advancements in wind energy farms in the developed world have significantly reduced the cost of wind energy turbine systems, making them more competitive and contributing to a reduction in global warming, which has a widespread impact on the global population. This study evaluates the wind energy potential of Auchi, a community in Edo State, Nigeria, using the Weibull distribution function. Wind speed data from NASA spanning an 11-year period (2012-2022) at a height of 10 m is utilized, and statistical methods are employed to estimate the Weibull parameters (scale and shape), which are then used to calculate the wind power density and the probability density function which was validated using root mean square error (RMSE) and coefficient of determination R2. The results indicate that Auchi possesses favorable wind conditions for power generation, with an average wind speed of 6.07 m/s and an average power density of 153.64 W/m². Additionally, the study examines the influence of surface roughness and height on wind speed and power density, highlighting the potential for harnessing wind energy for electrification purposes in Auchi, thereby offering a solution to Nigeria’s energy challenges.  
Design, Construction and Performance Evaluation of a Mucuna Bean Seed Cracker
Get PDFA cracking machine was developed for Mucuna bean seed. Design considerations and calculations were made using relevant equations and data from some engineering properties of the seed. A 2 hp electric motor running at a speed of 1400 rpm was used to transmit power to the gear mechanism. The cracker was fabricated using locally available materials to promote the possibility of replacing damaged parts. The performance of the machine was evaluated at various moisture levels since traditional post-harvest processing of the seed is moisture-dependent. The feed rate of the machine decreased as the moisture level increased. A significant decrease of 17.31 % was observed across the various moisture levels tested as the feed rate of the machine decreased from 8.01 to 6.59 kg/hr. At a moisture content level of 5.31 % (dry basis), the throughput capacity of the machine was obtained as 12.02 kg/hr, while between 9.14 to 11.52 % moisture content, it decreased by 3.5 %. The efficiency of cracking of the seed increased from 56.6 to 66.1 % as moisture content increased from 5.31 to 18.38 % (dry basis). The percentage of seed breakage also increased with moisture level. The seeds were observed to crack more efficiently when moisture was reduced. An average of 500 seeds were cracked within an hour, as against a minimum of 48 hours that would have been spent if the seeds were to be soaked in water before manual cracking.
 
Analysis of Normal Radar Signal Based on Different Time-Frequency Distribution Configurations.
Get PDFThe electromagnetic environment is becoming more complex, and radar technology is always evolving, as such, a sizable number of contemporary radars with agile waveforms have appeared on the battlefield. Relying solely on traditional recognition models to identify radar signals in electronic warfare systems is a significant challenge. In response to the this problem, this paper proposed an analysis of normal radar signal based on different time-frequency distribution (TFDs) configurations which include Wigner-Ville Distribution (WVD), Windowed Wille-Ville Distribution (WWVD), Filtered Wigner-Ville Distribution (FWVD), Choi Williams Distribution (CWD), and hybrid distributions that combined FWVD and CWD.A two-stage process in other to achieve the aim of this research is presented. The first stage is the modelling and generating a normal (simple) radar signal of pulse-to-pulse constant frequency, while the second stage involved designed of these TFDs and using them to analyse the radar signals. The result showed that most of the TFDs captured the time and frequency parameters of the radar signals modelled around of pulse width (PW) of 1µs, pulse repetition interval (PRI) of 2 µs, center and sampling frequencies of 10 MHz and 40 MHz respectively. Therefore, these TFDs can further be analysed using signal processing and classification tools such as instantaneous power, instantaneous frequency, and machine learning for automatic waveform recognition
Effect of Dielectric Properties of Building Structural Materials on Attenuation of Microwave Signals in Urban Areas of Nigeria
Get PDFDielectric properties determine how buildings attenuate communication signals. It is therefore an important factor in the propagation of signals. While building loss is an important parameter in link planning, it is often poorly characterized, and the data relating to the effect of building materials on propagation is either unavailable or poorly represented. In this paper, scattering parameters of typical urban buildings in Nigeria are measured to determine signal penetration loss for the frequency range of 800MHz to 3.2GHz. Building materials tested include reinforced concrete slabs, hollow sandcrete blocks, and prefabricated reinforced concrete slabs. The finishing of these materials ranged from burn bricks, rough paint, smooth paint, smooth wall tiles, smooth glassy tiles, to hardwood. The measurements were carried out using the oblique free-space measurement method. The dielectric properties of tested building materials were derived using the new non-iterative conversion method. Model equations that can predict scattering parameters and dielectric properties of a building given the test frequency and thickness of the building were also derived. Comparative analysis of the derived model with actual measurements showed an RMSE value ranging from 0.0192 to 0.2188. Results showed that the frequency of propagation, the thickness of the material under test (building wall), and building finishing affect the dielectric properties and contribute to the signal attenuation experienced in buildings. It was also seen that concrete structures had higher permittivity values hence they had difficulty with microwave signal penetration. Sandcrete blocks are therefore recommended for building walls in urban areas. 
Modeling of Field Efficiency of a Tine Harrow on Clay Loam Soil in Abia State
Get PDFThis study was conducted to model the field efficiency of tine harrow on clay-loam soil in Abia State using response surface methodology. This is to assist farmers and operators of the implement to evaluate and probably decide on appropriate harrowing implement depending on the type of soil for their seed bed preparation for efficient production at negligible energy loss. The operational speed (6-8 km/hr.), effective working width (60- 180 cm) and depth of cut (5-10 cm) were adopted as independent factors for the field efficiency study of the tine harrow. Results revealed that the highest field efficiency of 98.40% was recorded when the harrow was operated at the depth of 10cm, speed of 6km/hr. and effective working with of 180cm. The quadratic model was significant (P< 0.05) for the evaluation of field efficiency of the harrow. Results revealed that the coefficient of determination, R2 was 0.91, which indicated good relationship among the variables, also an indication that the response (field efficiency) could describe 91% of the overall erraticism within the response. Result of simulation achieved revealed that the field efficiency fall within the trial range. The predicted R2 (0.77) was compatible with the adjusted R2 (0.80) meaning that the investigational data fitted well
A Review and Critique of Advances in the Mitigation of Harmonics
Get PDFIn electrical power distribution systems, harmonics has always been a major concern as it can adversely affects the performance of the connected loads when tolerable or recommended standard limits are exceeded. There have been consistent and considerable efforts to study the sources, generation and control of harmonics over the years. This paper presents an extensive literature review of the major works on harmonics in the last two and a half decades. The merits and demerits, advantages and limitations of such work were critically reviewed. It was discovered that a lot remains to be done in the optimization of filters especially the hybrid types and that the design of a filter that can simultaneously mitigate low and higher order harmonics has not been thoroughly researched. This paper is intended as a guide for researchers that are interested in solving harmonics problems to identify the gray areas to concentrate and improve on
Development and Simulation of a Rotor Flux- Oriented Control Scheme for Efficiency Improvement in a Three Phase Induction Motor
Get PDFThe efficiency of induction motor drives under variable operating load and speed conditions can be improved by developing an algorithm that compute the optimum flux in the motor and commands a voltage that drives the motor at maximum efficiency for any given load and speed. This approach also helps to achieve significant amount of savings in electric energy consumption. In this paper, a method to optimize the flux of a three-phase induction motor and thereby maximize its efficiency for each load torque applied at a given speed, was developed. Mathematical models for the conventional rotor flux-oriented control scheme, total power loss as a function of rotor flux and for optimum flux as a function of operating speed and load torque were analytically derived. A MATLAB/Simulink model of the proposed rotor flux optimization scheme was developed to verify the analyses set forth for a typical three-phase Induction Motor. The results of the proposed method were compared with those of the conventional rotor flux control method and direct torque control (DTC) method in terms of loss reduction and efficiency for the same induction motor. The proposed rotor flux optimization scheme achieved 8.51% improvement in efficiency compared to the conventional rotor flux control scheme at a speed of 250 rad/s for a load torque of 3Nm. It also achieved 5.01% improvement in efficiency compared to the optimized DTC control scheme for the same speed and load torque. At a lower speed of 150 rad/s, power loss reduced by 17.1% while efficiency was higher by 5.7% for a load torque of 3Nm under the proposed scheme as compared to the optimized DTC schem
Optimization of Groundnut Oil Extraction using Chemical Method
No full textThe chemical extraction technique is associated with suboptimal oil yield and quality, necessitating the development of optimized extraction technique. In this study, groundnut oil was extracted chemically with n-hexane using the Response Surface Methodology (RSM) and the extraction process was optimized considering the hexane concentration (30, 40 and 50), extraction duration (3, 5, 7 hrs) and the amount of groundnut (15, 20, and 25 g) as factors and the oil yield was evaluated. The Fourier Transform Infrared (FTIR) technique was used to check at the functional groups on the extracted oil. In the experimental results, the average optimum values of extraction time, solvent amount, groundnut amount, and oil yield were 5.05 hr, 40.5 mL, 20.25 g, and 48.18%, respectively. The profiled extracted oil by FTIR showed peaks at 3452 cm-1 2969 cm-1 2712 cm-1 1763 cm-1 1474 cm-1 which indicates the existence of -CH and OH, CH, C-H, aldehydes, ketones, carboxylic acids, and methylene groups functional groups which are useful for determining the oil's quality. Furthermore, findings from this study showed that RSM-optimized process parameters result in significantly greater oil yields than conventional approaches.  
Mechanomyographic Amplitude Tracks Muscle Mechanical Responses During Nmes-Evoked Torque Production
Get PDFThis study investigates the pattern of relationship between mechanomyographic (MMG) signal amplitude and neuromuscular electrical stimulation (NMES)-evoked muscle contractions in healthy volunteers. Recent evidence has suggested that NMES-evoked muscle contractions enhance motor ability for physical performance in healthy individuals, maintain muscle health, and offset secondary complications of inactivity in persons with neurological conditions. However, the traditional NMES operation is inefficient, thus making the NMES outcomes less than optimal. Responsible for this is the lack of mechanical responses of muscle from the electrically-evoked limb during NMES-evoked contractions. This study investigated the use of a muscle contraction signal (mechanomyography, MMG) generated during NMES-evoked contractions in healthy knee extensors in tracking the muscle mechanical responses during NMES-evoked force production. Six healthy males underwent NMES-evoked submaximal-to-maximal isometric contractions, in random order, of their knee extensors at 30deg and 90deg knee angles on an isokinetic dynamometer. The MMG signal was acquired through an accelerometer sensor affixed to the rectus femoris (RF) muscle belly. Paired samples t-tests was used to compare the relationship between the two knee angles (90deg and 30deg) tested. Results show that the mechanomyographic amplitude (MMG-RMS) increased with increase in torque production and stimulation intensity up to 50 mA and 60 mA at knee flexion angles of 90deg and 30deg, respectively, before the appearance of plateau-like contractions—an indication of fusion of contracting muscle fibre at maximal contraction level. Although there were knee angle differences in the pattern of relationship between MMG and stimulation intensity, the effect was only statistically significant (p ≤ 0.05) for the torque versus stimulation intensity plot. These results suggest that MMG-RMS tracks motor unit recruitment strategy that might be responsible for muscle force/joint torque modulation during electrically stimulated contractions. The MMG signals may, therefore, have a clear application as an indicator of muscle force in areas where muscle force is needed and impractical to measure
Development of Smart Meter for Energy Billing and Power Management
Get PDFRising cost of energy tariff in Nigeria has brought to the fore the need for energy savings and power management. However, existing prepaid meters in the country are not user friendly. They do not give room for users to track power usage in a bid to observe the impact of load increase on units of energy purchased from utility providers. Load profiles like voltage, current and power of connected loads are not displayed on the energy meters making it impossible to conserve energy and manage power. In addition, these meters do not send notifications to consumers on the status of energy subscription. This study therefore developed a single-phase smart energy meter that availed consumers the opportunity of observing load changes on the screen from time to time. It notified customers via Short Message Service (SMS) when energy subscription was made and when unit of energy was low. The system consisted of hardware and software parts. The hardware parts composed of power supply unit, sensing unit, display unit, GSM module and energy meter. The software part involved programming ATMeg328P microcontroller enshrined on arduino Nano board using C# programming language. The system displayed energy worth of 50Wh for 4naira on the first recharge. This unit of energy was exhausted after leaving the system for several hours by connecting appliances like electric fan, soldering iron and electric iron. In particular, the system displayed power value of 114.73W when standing fan and two soldering irons were connected to the system. The power of connected load increased to 216W when electric iron was added. In addition, the system displayed unit of energy used and the remaining unit at every point in time. It also sent notifications to consumers through SMS to subscribe when energy unit was less than 5Wh and stopped working when energy unit was exhausted. It was therefore seen that the system was functional and displayed load profile (power and voltage) changes appropriately. The system is suitable for use in residential buildings, offices and applications where energy management is required