Department of Physical Sciences

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1-Minute Rain Rate Distribution for Communication Link Design Based on Ground and Satellite Measurements in West Africa
(Begell House, Inc., 2020) Sanyaolu, Modupe
West Africa is in the tropical region and it is characterized by intense rainfall. Rain is a significant factor causing signal degradation on microwave links due to its variability; it causes scattering, absorption, and refraction of electromagnetic waves. Experimental studies have shown that rainfall intensities above 64 mm/h at 0.01% in this region results in noticeable digital television signal fading, squelching and complete outages. Hence the need for estimating rain rate distribution across West Africa. This paper analyzed the rain rate from six countries in West Africa, namely Benin, Cameroon, Cote d'Ivoire, Ghana, Nigeria, and Togo. Three locations were selected in each country. Rain data were obtained from the Tropical Rain Measuring Mission-Precipitation Radar (TRMM-PR) and the Global Precipitation Measurement (GPM) missions, and Tropospheric Data Acquisition Network (TRODAN) weather stations in Nigeria. This study used ITU-R and Moupfouma models for the conversion of the 5-minute rain rate to 1-minute integration time at a probability of exceedance ranging from 1% to 0.001%. The cumulative rain rate distribution from the measured rain rate is presented alongside the predictions of the models. ITU-R and Moupfouma predicted similar results at 0.1% probability of exceedance. ITU-R overestimates the rain rate above 0.01% probability of exceedance. On the other hand, the Moupfouma models prediction plots at 0.01% overlap for all locations, indicating that there will be a signal loss at 0.01% probability of exceedance across these locations. The result shows that the 5-minute conversion provides satisfactory performance and suitable for estimating the 1-minute rain rate statistics required for propagation planning over West Africa.
Acoustic Vibrational Resonance in a Rayleigh-Plesset Bubble Oscillator
(Elsevier, 2020-09-23) Vincent, Uchechukwu
The phenomenon of vibrational resonance (VR) has been investigated in a Rayleigh-Plesset oscillator for a gas bubble oscillating in an incompressible liquid while driven by a dual-frequency force consisting of high-frequency, amplitude-modulated, weak, acoustic waves. The complex equation of the Rayleigh-Plesset bubble oscillator model was expressed as the dynamics of a classical particle in a potential well of the Liénard type, thus allowing us to use both numerical and analytic approaches to investigate the occurrence of VR. We provide clear evidence that an acoustically-driven bubble oscillates in a time-dependent single or double-well potential whose properties are determined by the density of the liquid and its surface tension. We show both theoretically and numerically that, besides the VR effect facilitated by the variation of the parameters on which the high-frequency depends, amplitude modulation, the properties of the liquid in which the gas bubble oscillates contribute significantly to the occurrence of VR. In addition, we discuss the observation of multiple resonances and their origin for the double-well case, as well as their connection to the low frequency, weak, acoustic force field.
An Automated Fraud Elimination Via Electrical Signal Monitoring And Recording Device (AFEESMR)
(Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS), 2018) Ilori Oluwaseyi Ayodeji
An Automated Fraud Electrical Signal Monitoring and Recording device was designed and constructed using all required electronic components. The device achieved the evaluation and monitoring of the time power was supplied through the public supply (Electricity) and the supply through the alternative power generator automatically via the indication of an on/off(0/1) states on the monitoring device for a specified period of time. The compilation and computation of the results over a certain time frame characterized signal strength which was used to checkmate the accuracy of an estimated electricity billing system, which is a common practice in this part of the nation by electricity distribution companies. The result from our investigation in a particular household in a specific month through the electrical signal monitoring and recording device reveals that, the bills send by the distribution company was outrageously estimated and fraudulent. As customers are made to pay for power they never use, this is also corruption. We opinion that the general acceptability of this device will help to reduce corruption in the public power sector as well as theft and fraudulent activities in large organizations that are using both electricity and alternative power generating system backups. In this specific nation where corruption is seen to be endemic, its reduction in the power sector will go a long way to foster national development and sustainable economy as well as improving the standard of living of the populace.
An IoT-Based Home Automation and Weather Monitoring System
(International Journal of Research and Innovation in Applied Science (IJRIAS), 2022-03) Ilori Oluwaseyi Ayodeji
This paper reports an IoT-based home automation and weather monitoring system developed for remote control of household appliances and weather monitoring. The proposed system comprises a Wi-Fi enabled ESP32 microcontroller as the network gateway, a relay module, and a DHT11 sensor for monitoring temperature and humidity. The status of the household devices and the weather data are continuously collected and stored in a MySQL database, which is set up on the IoT platform. A user interface was created using two different protocols - HyperText Transfer Protocol (HTTP) and Message Queuing Telemetry Transport (MQTT). The IoT-based home automation and weather monitoring system is designed to be low cost, user-friendly and can remotely control home appliances and monitor weather data over the internet.
Analysis of Rain Fade Durations on Communication Links at Ka Band in Nigeria
(International Journal of Recent Technology and Engineering (IJRTE), 2020) Willoughby, Alexander
Duration of rain fade events is a major parameter to be considered when designing a communication link. Fading is a phenomenon responsible for intermittent fluctuations of radio signals observed in the tropical region. The prevalence of rain in the tropics accounts for the frequency of fading observed in this region. This study investigates the number of fade events per fade duration interval exceeding attenuation thresholds ranging from 1 dB to 18 dB at 40 GHz. The range of fade durations is from 10 s to 5000 s. The International Telecommunication Union (ITU-RP) propagation model and data from the Tropospheric Data Acquisition Network (TRODAN) were used for the analysis. The eight TRODAN stations, under the Centre for Atmospheric research (CAR), an activity Centre of the National Space Research and Development Agency (NASRDA) in Nigeria, cover the major climatic regions in the sub-Saharan region, namely equatorial, humid tropical and tropical zones (Geo. 4:82 N to 9:58 N). The results show that fade duration decreases as attenuation increases across all the locations. The implication is that heavy rains, causing higher attenuation, occur for shorter time duration. Similarly, higher attenuation depends on raindrops size and rain intensity. Consequently, the frequency of fade events exceeding 1 dB threshold is higher than other thresholds with respect to the fade duration.
Anode Materials for Lithium-based Batteries: A Review
(2020-06-26) Soge, Ayodele
Graphite as a conventional anode material has been unsuccessful in satisfying the requirements of future high-performance lithium-ion batteries due to its low theoretical specific capacity (372 mAh g−1) and low operating potential (~0.1 V). This has resulted in strong demand for new anode materials with high reversible capacity and stable cycling life. Thus, diverse new anode materials have been proposed as a replacement for graphite in recent years. The novel materials reviewed in this study include transition-metal compounds, silicon-based compounds, and carbon-based compounds. The prospects of these materials in developing high-performance lithium-ion batteries for electric vehicles and large-scale energy storage applications are also highlighted.
Arduino-Based Maximum Power Point Trracking Charge controller using Perturb & Observe and Constant-Voltage Algorithm
(International Journal of Energy for a Clean Environment, 2023) Ilori Oluwaseyi Ayodeji
The output power delivered by a photovoltaic (PV) module to charge a battery is dependent on solar radiation incident upon it and the ambient temperature. To reduce PV energy loss, the PV panel is kept at peak efficiency by operating the PV system at the maximum power point (MPP) to deliver maximum power to the battery under charge. In this work, Perturb & Observe (P&O) algorithm was implemented in conjunction with constant voltage (CV), using the MATLAB/Simulink tool. Results obtained from these simulations show that the tracking efficiency of the P&O algorithm decreases with solar irradiation. However, the relatively good performance of the CV algorithm at low irradiation levels augments the P&O method. Both algorithms were implemented in a maximum power point tracking (MPPT) design using an ATMega328 microcontroller operating on a minimal Arduino-compatible integrated development environment (IDE) prototype circuit.
Assessment of Five Predictive Models for Solar Radiation in Southwest Nigeria
(Nigerian Journal of Environment and Health, 2021) Willoughby, Alexander
This study compares the accuracies of five predictive models for estimating solar radiation amongst other meteorological parameters in Southwest Nigeria. Twenty-one years of monthly averages of six measured meteorological parameters obtained from six stations in southwest Nigeria have been subjected to five mathematical models for prediction purposes. Solar radiation and sunshine hours have been modelled using the sum of two-Gaussians, the sum of two-Lorentzians, Fourier on four harmonics, sine wave and fourth-order polynomial functions. The fitting accuracies of these models were tested using performance indicators; mean bias error (MBE), root mean square error (RMSE), mean percentage error (MPE), standard error (SE) and the correlation coefficient (R). An evaluation of the models showed that the Gaussian and Lorentzian models are in good agreement with the observed data. However, the Fourier on the fourth harmonics model had the lowest MBE, RMSE and MPE, consequently highest correlation coefficient values, indicating high model accuracy. Thus, the Fourier model has the best correlation with the observed data and is recommended for estimating these variables in the selected locations.
Assessment of Musculoskeletal Discomfort among Mini-Bus Drivers in Osun State, Nigeria
(International Journal of Progressive Sciences and Technologies (IJPSAT), 2022) Sanyaolu, Modupe
There have been many reports on the physical factors contributed to the development of work-related musculoskeletal disorders (WMSD) which have a negative influence on the health of employee across different occupations including bus drivers. This study focuses on the assessment of musculoskeletal disorders among mini-bus drivers popularly called “Korope” in the Osun State of Nigeria. This research is based on questionnaires extracted from the standard Nordic questionnaire for the assessment of musculoskeletal disorders (MSDs). The results obtained from the questionnaire showed that the low back, knee and the ankle/feet were found to be the most common areas of discomfort among the population. The elbow showed the least area of musculoskeletal discomfort while the shoulder,upper back, neck, thigh/hips and the wrist/ hands showed moderate discomfort. Some of the subjects experienced at least two of the discomforts.
Atmospheric Aerosol Loading at Ilorin, a Tropical Station
(The African Review of Physics, 2014) Willoughby, Alexander
This work reports the inter-annual variability of the seasonally recurring aerosol haze at Ilorin (8°32¢N, 4°34¢E) a central state of Nigeria, which is in the tropical zone. The data consist of observations collected over a period of seven years 1987 –1990 and 1996 - 1998 using the EKO Sun-photometer model SM –120 with “peak hold” and full view 2.4°quartz window and interference filters having peak transmission at the wavelengths 500, 675, 875 and 945nm, respectively. The data coverage presents to us five distinct aerosol seasons viz: 1987/88, 1988/89, 1989/90, 1996/97 and 1997/98. The data collected for all the aerosol seasons were compared wavelength-by-wavelength and month-by-month. Although the regional mean Aerosol Optical Depth (AOD) and Precipitable Water (PW) remains essentially constant in trend for all the data years, they vary from year to year with spread ranging from 0.789 to 1.526 for AOD1, 0.808 to 1.50 for AOD2, 0.814 to 1.178 for AOD3, and 0.340 to 1.480 for the PW. The coefficient of variation determined is between 27.4 and 52.0 for AOD1, 23.9 and 53.2 for AOD2, 25.2 and 52.8 for AOD3 and 12.9 and 39.5 for PW. The Angstrom exponent was also found to vary from about 0.2 to 3.8.
Cathode Materials for Lithium-ion Batteries: A Brief Review
(Journal of New Materials for Electrochemical Systems, 2021-10) Willoughby, Alexander
Layered lithium cobalt oxide (LiCoO2) as a pioneer commercial cathode for lithium-ion batteries (LIBs) is unsuitable for the next generation of LIBs, which require high energy density, good rate performance, improved safety, low cost, and environmental friendliness. LiCoO2 suffers from structural instability at a high level of delithiation and performance degradation when overcharged. Besides, cobalt, a significant constituent of LiCoO2 is more costly and less environmentally friendly than other transition metals. Therefore, alternative cathode materials are being explored to replace LiCoO2 as cathode materials for high-performance LIBs. These new cathode materials, including lithiated transition metal oxides, vanadium pentoxides, and polyanion-type materials, are reviewed in this study. The various challenges hampering the full integration of these cathode materials in commercial LIBs and viable solutions are emphasised.
Chaos Synchronization Based on Linear and Adaptive Controls: Theory and Experiment
(2021-10-30) Vincent, Uchechukwu
In this paper, we report on the theoretical and experimental investigation of chaotic synchronization using of a single-variable linear feedback and adaptive controllers. Based on the Lyapunov stability theory, theoretical approaches to the design of controls are presented, and the results are validated numerically and by employing electronic circuit experiments. We used two typical oscillators, namely, the Lorenz and Sprott chaotic systems to demonstrate our results; while off-the-shelf components on breadboard were used to experimentally implement the proposed single variable controllers. We specifically show that synchronization of two chaotic systems can be experimentally realized when the strength of the feedback exceeds a theoretically determined threshold
Characteristics of Rain Fade Slope on Microwave Communication in Mowe, Nigeria
(IOP Publishing, 2021) Sanyaolu, Modupe
In this paper, the rain fade characteristics at Ka-band (30 GHz) in Mowe (Lat 6.80º N, Lon 3.40º E) Nigeria have been presented. The analysis includes both the first- and second order statistics of rain rate and rain attenuation, and fade duration and fade slope, respectively. Both parameters are useful for planning the point-to-point microwave link for various communication feeder networks. The estimated fade duration and the fade slope were compared with the ITU-R P.837-5 model. The results of this study would be valuable for improving rain fade mitigation techniques in Nigeria.
Characteristics of Rain Fade Slopes on Microwave Communication in Mowe
(Journal of Physics Conference Series, 2021) Akinyemi, Gbenga
Characteristics of Rain Fade Slopes on Microwave Communication in Mowe, Nigeria
(Journal of Physics: Conference Series PAPER, 2021) Willoughby, Alexander
In this paper, the rain fade characteristics at Ka-band (30 GHz) in Mowe (Lat 6.80º N, Lon 3.40º E) Nigeria have been presented. The analysis includes both the first- and secondorder statistics of rain rate and rain attenuation, and fade duration and fade slope, respectively. Both parameters are useful for planning the point-to-point microwave link for various communication feeder networks. The estimated fade duration and the fade slope were compared with the ITU-R P.837-5 model. The results of this study would be valuable for improving rain fade mitigation techniques in Nigeria.
Comparison of the sensitivities and accuracies of optoelectronic transducers for solar irradiance measurement
(Springer, 2023-12-01) Soge, Ayodele O.
This paper compares the sensitivities and accuracies of four different optoelectronic transducers in measuring solar irradiance for the fabrication of portable and low-cost pyranometers. Trans-impedance conditioning circuits were designed for two phototransistors (BP103 and SFH3310) and two photodiodes (BPW21 and BPW34). The Arduino MEGA 2560 was used as an interface between the analogue signal produced by the conditioning circuits and the digital output ports. The transducers with a standard pyranometer RSRA_05V were arranged on a vero board and exposed to the sun. Statistical analysis of the experimental results produced the least root mean square error value of 6.58794 Wm-2 for phototransistor BP103 during the dry season followed by 13.35216 Wm-2 for phototransistor SFH3310 during the dry season. The correlation coefficients of BPW21, BPW34, BP103, and SFH3310 with the standard pyranometer are 0.9489, 0.9916, 0.9976, and 0.9905, respectively. The experimental results obtained from the phototransistors BP103 and SFH3310 strongly correlated with those of the standard pyranometer coupled with lower root mean square error and mean bias error values than the photodiodes. Thus, the phototransistors BP103 and SFH3310 are more accurate and effective for measuring solar irradiance. This study contributes to the development of low-cost and accurate solar radiation meters.
Controls on the compositional framework and petrogenesis of Early Cretaceous first cycle quartzose sandstone, North Gondwana
(Elsevier, 2021-09-10) Adepehin, Ekundayo Joseph
Recent advances in sedimentary research have shown that quartz sandstones are scarce in the global geologic record and prolonged sediment transport does not automatically produce mineralogically mature sediments. Published data are based mainly on Cambro-Ordovician arenites. This paper discusses the formational controls of early Cretaceous syn-rift quartzose from northern Gondwana based on integrated petrographic, mineralogic, and electrofacies proxies on the Upper Sarir Sandstone Formation, Sirte Basin, Libya. The study aimed to understand the compositional framework and construe the sedimentological processes that produced the quartz-rich sandstones. Acquired samples (n=40) from three boreholes (N8-97, N7-97, and N4-97)were subjected to petrographic analysis, x-ray diffractometry, and variable pressure scanning electron microscopy with energy dispersive x-ray spectrometry. Qualitative and quantitative datasets indicate that the mean framework composition (Q97F0L3) of the sample is quartz-dominated and primarily detrital, although diagenetic imprints, mostly quartz cementation, quartz overgrowth, and other authigenic precipitates, are present. Evidenced by the predomination f monocrystalline quartz grains (99.10%) over the polycrystalline type (0.90%), the dominance of nonundulatory extinction (72.50%), and noticeable euhedral crystals, the compositional framework of the studied quartzose reflects a predominant plutonic provenance with some metamorphic inputs. The possibility of significant sediment reworking is ruled out based on short to moderate transport distance (~100 km) interpreted from the interplay of textural parameters, depositional model, and paleogeography. A humid paleoclimate alongside its associated rigorous chemical weathering is constrained as the dominant control in the formation of the Upper Sarir quartzose sandstone from a dominant craton interior provenance. These conditions probably produced other early Cretaceous arenitic sandstones in other reaches of North Gondwanaland.
A Cost Effective Solar Charge Controller and Load Driver for DC Home Appliances
(IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE), 2015-10) Willoughby, Alexander
Crisis-induced vibrational resonance in a phase-modulated periodic structure
(The American Physical Society, 2024-09-25) Vincent, Uchechukwu E.
Double vibrational resonance is reported for a driven oscillator in a periodic structure of the Josephson junction type with high-frequency phase modulation. We identify two distinct phase modulation effects, namely, resonant induction and resonant amplification, leading to the appearance of a double resonance. We analyze these vibrational resonance phenomena theoretically and numerically, and we show that the origin of the induced resonance is traceable to a transition from periodicity to quasiperiodicity associated with an attractor-merging crisis.
Design and Construction of a Photovoltaic Monitoring System Based on Wireless Sensor Networks and Internet of Things Technology
(Springer, 2024-05) Soge, Ayodele O.
Poor monitoring of a photovoltaic (PV) system is responsible for undetected faults that reduce the energy produced by the system and in the long run decrease its lifespan. However, this challenge can be overcome by real-time monitoring of the electrical and environmental parameters of the PV system. Several wireless real-time monitoring systems are available, but none have a backup storage device and could only monitor a few parameters at a relatively high cost. Besides, these systems cannot monitor the battery storage and the inverter output, thus failing to meet the IEC-61724 standard. In this paper, we report a robust monitoring system developed for both local and remote real-time monitoring of a PV system. The electrical and environmental parameters of the PV system were monitored and saved using wireless sensor networks and Internet of Things (IoT) technology. This was achieved using two Atmega 328P microcontrollers, which formed the data acquisition units, and an ESP32 microcontroller for the master terminal unit. The data acquisition unit consists of two nodes: the PV node, and the battery node. All data are received by the master terminal unit and sent to the ThingSpeak online server using the IoT capability of the ESP32 microcontroller. The developed system was installed in a 12 V, 200 W standalone PV system and all desired parameters were successfully monitored, logged, and transmitted to the cloud in real time for easy accessibility by the users via the internet.

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