Physics

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    Development of an Automatic Body Mass Index Measurement Machine
    (2019-05-12) Theophilus Ewetumo, Kayode D. Adedayo, Yusuf B. Lawal, Abiodun T. Edun and Joseph E. Orokhe
    The potential occurrence of certain illnesses can be easily diagnosed through measurements of some health indicators. One of such parameters is the Body Mass Index (BMI). BMI is simply the ratio of mass (kg) of a body to the square of its height (m2 ). This research presents the design and construction of an automated BMI measurement machine for medical purposes. It consists of three major units: the weighing unit (5 – 200 kg); height-measuring unit (0.02 – 2 m) and the processing unit. The weighing unit is made up of load button cell and load cell amplifier while the height-measuring unit consists of ultrasonic sensor. The analog differential output voltage from load cell is connected to Arduino microcontroller via a Programmable Gain Amplifier (PGA) integrated with Analogue-to-Digital Converter (ADC). The two units are connected to an open source Arduino Uno which computes mass-to-body ratio and sends the output results (mass, height and BMI) to the liquid crystal display (LCD). The weighing system was calibrated against a precision digital weighing system and it gave a correlation of 0.99. The height measurement was also compared with manual height measurement using a tape rule which gave a correlation of 0.97. The developed Instrument is cost effective and has high positive correlation with the standards (weighing scale and tape rule), it is therefore recommended for the measurement of weight, height and BMI.
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    Development of Viscosity Measuring Device Using Vibrational Technique
    (2018-07-23) T. Ewetumo, K. D. Adedayo, M. A. Sodunke and Y. B. Lawal
    The project centers on the development of viscosity measuring device using vibrational techniques. The instrument consists of a variable power supply, two solenoids each with plungers, needle with a pendulum bob attached, switching circuit, current – voltage sensors, microcontroller, analog–to– digital converter and Liquid Crystal Display (LCD) unit. The developed system consists of a variable power supply used to create varying magnetic fields in the solenoids so that the plungers can attract and release the pendulum bob. As the magnetic field strength varies, the pendulum experiences force sufficient to overcome the internal friction within the liquid. The pendulum bob is thus set into periodic to and fro motion. The pendulum bob movement was monitored by a microcontroller through a reflective optical sensor. Viscosity was measured through the calibration constant generated from a liquid of known viscosity, applied voltage, current generated from the solenoids and the dragging time. Gear oil, engine oil, palm oil, olive oil were the fluids investigated with the developed system for performance evaluation. Statistical analysis revealed a percentage error value of 2.87% and accuracy of 97.13% which shows a good agreement between the standard and what is available in the literature. The instrument performed well and it is therefore suitable for the measurement of liquids' viscosities.
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    Development of a Microcontroller Based Heat Index Meter
    (JOST, 2023-04-07) Lawal, Y.B.
    The research focuses on the development of a heat index meter using microcontroller technology. A DHT22 thermo-hygrometer sensor was employed to measure ambient temp and relative humidity simultaneously. The analogue values of these parameters were fed into Arduino Uno Microcontroller which is the heart of the developed meter. The microcontroller has been programmed to compute the heat index using an embedded equation. The microcontroller is interfaced with a 16 by 2 Liquid Crystal Display (LCD) to display the measured temperature, relative humidity as well as the computed heat index. The developed instrument performed satisfactorily during testing and evaluation. It is therefore recommended for measurement and monitoring of heat index.
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    Design and Construction of a Two Channel Microcontroller Based Remote Control for Switching Electrical Appliances
    (ABUAD, 2020-04-14) Mobolaji Aduramo SODUNKE, Adeyemi Idris OLATEJU, Yusuf Babatunde LAWAL, Joseph Ogheneruemu ODIETE, Taiwo Titus ABATAN, Waliu Olayemi MUFUTAU
    This paper presents the design and development of a microcontroller-based system that can switch off and on Electrical appliances or wall sockets at user’s will remotely. This research is aimed at increasing the accessibility as well as response rate to prevent appliances from damage due to transient, intermittent and fluctuations in power supply. This system uses a wireless telemetry technique through an infra-Red (IR) transmitter and receiver to control the switching state of home and laboratory/industrial electrical or electronic devices. The entire circuit is built around ATMEGA-328P microcontroller which was programmed to interpret digital signal sent from the IR transmitter (remote control) to the IR receiver. As the microcontroller receives a real time signal from the IR transmitter through the IR receiver module, a command is sent to the relay switching unit which activates or deactivates the channel(s) based on the software code embedded in the microcontroller. The normally open (N/O) and normally closed (N/C) terminals of the relay are connected to the live terminals of AC sockets for automation. The Liquid Crystal Display (LCD) displays the status of the sockets in any of the two channels (points) as instructed by the microcontroller. The system is cost effective, durable and versatile as it can be applied to any devices connected to electrical socket outlet.
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    DESIGN AND CONSTRUCTION OF A DARK-ACTIVATED EMERGENCY MAINS FAILURE TORCH
    (GVU Science, 2023-08-02) Dada, J. B.1* and Lawal, Y. B.
    This paper presents the design and construction of a dark-activated emergency mains failure (DAEMF) torch mounted on a printed circuit board (PCB). The battery-powered torch called a DAEMF is intended to automatically light up a home and its surroundings in the dark, but it will turn off if it detects the presence of a power source, even if the lighting system is not on. The charging, switching, and lighting sections comprise the three main sections. During the dark period, the switching circuit was switched ON by a voltage of 1.7 volts, and a current of 0.006 mA measured across the light-dependent resistor (LDR) at the switching section. The charging section uses a linear Integrated Circuit (IC) LM 317 as the main electronic component to charge the battery with about 0.65A load current. The high-voltage transformer (HVT) at the lighting unit inverts and converts a 12 Volts direct current (DC) to approximately 100 Volts alternating current (AC) to drive the 6 watts 12 volts fluorescent tube in the lighting section to illuminate the household and its surrounding for 10.5 hours of continuous use
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    Construction of an Automatic Temperature Controller for Monitoring Heating and Cooling Systems
    (Centre for Research and Development (CERAD), 2016-04-02) LAWAL, B.Y, DADA, J.B. and AHMED-ADE, F.
    The Automatic Temperature Controller (ATC) is a locally designed microcontroller borne electronic circuit system capable of monitoring and controlling the temperature of a thermally isolated enclosure or chamber, provided the heating or cooling source is powered electrically. Monitoring and automation are achieved with the aid of Temperature sensor, Microcontroller IC, Analogue-to-Digital Converter (ADC), Liquid Crystal Display (LCD) unit, Switching circuit and other essential components. The Microcontroller has been programmed to monitor and control instantaneous temperature values received from a temperature sensor. The preset values determine whether a relay is energized or de-energized. The switching terminal of the relay has been connected in series to the live terminal of the mains that powers an electrical heating or cooling systems. The circuit can be employed in managing the temperature of drying compartments such as House warmer, heating furnace, incubators, and others. The temperature range of the system is between 4oC and 130oC with a resolution of 0.5oC
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    Comparative Analysis of Surface Refractivity Variations in the Sahel and Coastal Zones of Nigeria
    (Science Publishing Group, 2023-04-03) Yusuf Babatunde Lawal, Joseph Babatunde Dada
    Variation in Surface Refractivity N is largely influenced by changes in some meteorological parameters such as air temperature, relative humidity, and pressure. These parameters are more accurate when measured locally due to their temporal and spatial variations. The research studies and verifies the contributions of the dry and wet term components of surface radio refractivity. The research focuses on the comparison of surface refractivity variations in two geoclimatic zones of Nigeria. The study reveals that the Sahel and Coastal zones have dissimilar distinct weather conditions and consequently diverse variational pattern of their surface refractivities diurnally and seasonally. The diurnal values of surface refractivity vary moderately on typical sunny days with average values of about 345-391 N-units and 275-314 N-units in the Coastal and Sahel respectively. Wider daily variations were observed during the rainy season in both geoclimatic zones due to frequent rainfalls, especially in the Coastal Stations. The average daily refractivity in the Coastal and Sahel during the rainy seasons are 339-390 and 311-384 N-units respectively. Analysis of the results obtained indicates that the annual mean of the ITU-R recommendation underestimates surface refractivity by 11-15% across the coastal stations and by 5-10% across the Sahel zone. The derived values for each station would be useful for radio engineers in the design and optimization of terrestrial radio links.
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    Chaotic assessment of the key performance indicators for a GSM Network congestion in an election period in Nigeria
    (Nigeria Journal of Pure & Applied Physics, 2019-05-06) A. O. Adelakun, B. Y. Lawal, M. A. Adekoya, K. E. Ukhurebo
    This paper investigates the chaos-based assessment of the Key performance Indicators (KPIs) for the Cellular network congestion during and after 2011 People Democratic Party (PDP) presidential primary election in Eagle Square within Abuja and its environs. Chaotic quantifiers such as average mutual information, Lyapunov exponents and specific attenuation were employed to study the congestion rate or dynamical state of the network. The chaotic assessment of the Wideband Code Division Multiplexing Access (WCDMA) data services provided by MTN network using KPIs are reported. The data retrieved from the three Base Transceiver Stations (BTSs) were used to analyse the performance of the network. The results revealed the state of dynamical behaviour of the congestion during the study period.
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    Analysis of Cross-Polarization Discrimination Due to Rain for Earth–Space Satellite Links Operating at Millimetre-Wave Frequencies in Pretoria, South Africa
    (MDPI, 2025-06-16) Yusuf Babatunde Lawal, Pius Adewale Owolawi and Joseph Sunday Ojo
    This study investigates the impact of rain-induced attenuation on cross polarization discrimination (XPD) in Earth–space satellite links operating at millimeter wave frequencies in Pretoria, South Africa. The traditional method of computing XPD employs a constant annual mean rain height and annual mean co-polar attenuation (CPA) over a certain location. This research utilized seasonal rain height data obtained from a recent study and the latest ITU-R P.618-14 guidelines, to compute and analyze XPD variations across six selected frequencies (11.7 GHz to 35 GHz) for different percentages of time exceedance in Pretoria. The study reveals significant seasonal dependencies of rain heights, with XPD reaching its maximum during winter due to lower rain height, and lower rain-induced attenuation and its minimum during summer, characterized by intense convective rainfall and maximum rain height. FFor instance, the estimated XPD for a 35 GHz signal at 0.01% of the time in the summer, spring, winter, and autumn are 13, 14, 15, and 14 dB, respectively. This implies that radio signals suffer severe attenuation caused by low XPD in the summer. The relationship between CPA and XPD highlights the need for increased XPD margins at higher frequencies to mitigate signal degradation caused by rain depolarization. Practical recommendations include the adoption of adaptive modulation and coding schemes to maintain link reliability during adverse weather conditions, particularly in summer. This research highlights the significance of incorpo-rating frequency-dependent parameters and rain height variability in XPD estimation to enhance the design of satellite communication systems, ensuring optimized performance and reliable operation in a tropical climate.