Engineering Headway Vol. 33

Abstract: A study was conducted to evaluate the soil strength, physicochemical characteristics and yield of fluted pumpkin (Telfaira occidentalis) under different fertilizer sources in an Afisoil of Akure, Ondo State, Southwestern Nigeria. Four treatment, which include: Poultry manure (10 tom/ha), organomineral fertilizer (5 tom/ha), mineral fertilizer (5 tom/ha) and the control (0 fertilizer), replicated four times in a randomized complete block design (RCBD) were experimented in two blocks to make a total of 32 plots. Soil samples were collected randomly at 100, 200, 300, 400 and 500 mm depths and analyzed to determine bulk density (BD), total porosity (PT), micro porosity (MIP) and macro porosity (MAP) following standard procedures. Plant parameters (plant height, number of leaves, stem girth and leave yield were measured weekly to determine response of fluted pumpkin to the different fertilizer sources. Results showed that the soil of the site is predominantly sandy clay loam. The pH of the soil under the different fertility treatment showed an increasing order of the form: mineral fertilizer (MF) < control (C) < Organic manure (OM) < organomineral fertilizer (OML) with values 4.26 < 4.96 < 5.46 < 5.5. Leaf yield of fluted pumpkin was highest in treatment plot that received mineral fertilizer when compared with other soil treatments. Fertlizer sources produced no significant difference (P > 0.05) in the height of fluted pumpkin. Result of this research is useful for local farmers and policy makers in the choice of appropriate soil amendment and management system for fluted pumpkin in the study area.

Abstract: A prototype drainage lysimeter system was designed and constructed for educational objectives, focusing on the principles of drainage and irrigation systems. The fabrication was carried out at the Engineering Section of the Farm Mechanization Unit within the Agricultural Technology Department at the Federal College of Freshwater Fisheries Technology in New Bussa, Niger State, Nigeria. The drainage lysimeters were made from 4.8-mm waterproof plywood, measuring 0.80 x 0.45 x 0.50 m, with an internal area of 0.18 m². A lysimeter filled solely with moist soil weighed 1,010.27 kg. This prototype was utilized in practical classes to instruct students on assessing water infiltration rates, evapotranspiration, water quality, and crop water usage. Evaluation results indicated that students successfully grasped the operational principles of the drainage lysimeter system.

Abstract: Effective thermal management is critical to the performance and reliability of solid-state drives (SSDs), especially in high-power applications where passive cooling remains the preferred solution due to space, noise, and energy constraints. This study investigates the impact of key design parameters—casing material, heat sink base thickness, and fin spacing—on heat dissipation from the chip to the casing under natural convection conditions. A three-dimensional finite volume method (FVM)-based thermal model was developed and validated experimentally, with chip and casing temperatures measured across various operating voltages. The model showed strong agreement with experimental data, with average deviations below 4%. Temperature contour analysis revealed that aluminum casings enabled more uniform heat distribution and lower thermal resistance compared to ABS, resulting in a chip temperature reduction of up to 9.28 °C. Increasing the heat sink base thickness from 1.0 mm to 3.0 mm further improved heat conduction, while fin spacing had a minor influence on performance. Taguchi optimization using chip-to-casing temperature drop as the performance metric identified the optimal configuration as an aluminum casing, 3.0 mm base thickness, and 2.4 mm fin spacing. This combination achieved the lowest chip temperature (52.18 °C) and minimal thermal resistance. The findings provide design insights for enhancing passive thermal solutions in high-power, compact SSD systems.

Abstract: Effective thermal management is essential for maintaining the performance and reliability of high-power semiconductor devices. This study presents a combined numerical and experimental evaluation of heat sink geometries under natural convection cooling to reduce junction temperatures in compact electronic packages. A three-dimensional finite volume model was developed in ANSYS Fluent to simulate the thermal behavior of a semiconductor package consisting of a chip, controller, thermal pad, and heat sink. The model was validated experimentally using thermocouples and a data acquisition system, with simulation results closely matching measured data, showing errors below 0.5%. Parametric investigations were conducted to assess the effects of heat sink fin number, fin height, and fin shape on junction temperature. Results showed that increasing the number of fins initially enhances heat dissipation, with an optimal range observed between 6 and 8 fins. Fin height had a strong influence, with taller fins significantly reducing junction temperature, up to 29.66 °C compared to the baseline model. Among the evaluated shapes, parallel and pin-fin heat sinks achieved the best performance, with over 23 °C reduction in junction temperature, while the wavy-fin design was less effective due to induced airflow disturbance. These findings provide practical insights into heat sink geometry optimization for passive cooling systems and offer guidance for thermal design in high-performance semiconductor applications.

Abstract: The widespread adoption of broadband networks has significantly boosted economic growth and transformed various sectors. While mobile broadband (MBB) has gained widespread acceptance due to its flexibility and mobility, fixed broadband (FBB) networks offer superior performance, supporting multiple users and devices without compromising speed. FBB's high-speed internet, stability, and large data capacity make it ideal for data-intensive activities like remote work, online learning, and video conferencing. However, ensuring reliable and high-quality services remains a concern, prompting researchers, governments, and regulators to develop unbiased performance measurement methodologies for FBB networks. This paper reviews existing approaches, tools, and frameworks for assessing Quality of Service (QoS) and Quality of Experience (QoE) in FBB networks, highlighting regional and stakeholder disparities. Key performance indicators like bandwidth, latency, jitter, and packet loss are examined, along with challenges related to measurement consistency, standardization, and transparency. The findings emphasize the need for robust, cost-effective, and transparent measurement frameworks to ensure fair evaluation, enhance service delivery, and promote digital inclusion globally.

Abstract: The demand for and usage of radio spectrum over the last three decades have increased geometrically throughout the world as a result of daily increase in new wireless services and applications that are in need of radio spectrum. However, the current fixed allocation policy currently being using in radio spectrum management has made availability of radio spectrum for the new emerging wireless services and applications practically infeasible since all available radio spectrum had been allocated nationally and internationally. Nevertheless, results of recent radio spectrum occupancy measurements conducted in several parts of the world had revealed that most of the allocated radio spectrum under the current fixed allocation policy nationally and internationally was underutilized. In additional, the results of some of the spectrum occupancy measurements conducted also showed that the usage of most already allocated radio spectrum varies with time, space and frequency. In order to experimentally verify the actual radio spectrum usage in Nigeria, radio spectrum occupancy measurements were conducted in three major cities in South-West geopolitical zone of Nigeria. The analysis of the results of the radio spectrum occupancy measurements conducted show that the actual radio spectrum usage in the three cities follows the same pattern with the rest of the world with actual usage varies with time, space and frequency with actual overall percentage of occupancy less than 26.0%. The analysis of the results of the occupancy measurements conducted also show that while some allocated radio spectrum were sparsely used, some were medially used and some were heavily used.

Abstract: This study explores the influence of atmospheric wind speed on the reliability and performance of Free Space Optical (FSO) communication systems. Atmospheric turbulence, largely induced by variations in wind velocity, distorts optical signal propagation through effects such as beam wander, scintillation, and attenuation. A simulated experimental setup comprising a laser Transmitter circuit, photodiode Receiver, and a potentiometer to emulate varying wind speeds—was used to prove its effect on the laser signal under varying wind speed. The simulation results indicate that increased turbulence demands higher transmitter current to maintain signal integrity. The simulation results also highlights the corresponding decrease of 0.22 V as the resistance of the potentiometer was increased to 1000 Ω.

Abstract: Prolonged sedentary behavior in office environments has been linked to musculoskeletal disorders (MSDs), poor circulation, and decreased workplace productivity. Despite the advancements in ergonomic chair design, traditional models remain passive solutions that rely on user engagement for adjustments, often leading to improper usage and ineffective sitting management. This paper presents the smart health-based office chair, an innovative approach that integrates ergonomic principles, anthropomorphic interaction, and smart technology to actively promote healthy sitting behavior. The conceptual work employs the use of SolidWorks for designing different graphical concept models, which were ranked using the Pugh matrix for determining the best concept. After which, electrical components simulation was carried out using “Tinker Cad” and “Wokwi”. The research finding shows that the conceptual model with the following features: visual alert, alarm sensory system, multi-sensory feedback mechanisms, voice prompts, haptic vibrations, and LED alert has the highest score weight of 250 based on standard operational practices. Prototyping, components integration of microcontroller, calibration of sensors, actuators performance trials, and quantitative data analysis were further considered on the best concept model that emerged. The results showed that the chair has an average performance rating of 84%, as the expected outcome includes reduced prolonged sitting, lower MSD risk, increased movement compliance, and improved work productivity. The total cost for completion of the chair was estimated at two hundred dollars only.

Abstract: Heart diseases are one of the leading causes of death worldwide. Therefore, there is the need for a device that can track the heart performance to provide insights on those conditions such as abnormal heart rates which require urgent medical attention and can result in loss of life. This work developed an internet of things (IoT) based heart rate monitoring system. The key components of the system developed include a pulse sensor (SEN-11574), an arduino uno microcontroller, a liquid crystal display (LCD) module, ESP-8266 Wi-Fi module, 18650 batteries and light emitting diodes (LEDs). Using appropriate design models and relevant mathematical algorithms, circuit designs were accomplished with a microcontroller as the central component. A wireless data transmission unit was created using ESP-8266 Wi-Fi module and Thingspeak platform. Performance test was carried out on each of the subunits of the developed system. Heart rate measurement test was conducted on thirty (30) people and compared with the measurements from an existing heart rate monitor (Apple watch series 7) to determine the reading error of the device. The results of the performance test showed that the developed system operated as intended. The device’s reading error was 3.11% for readings obtained while at rest and 3.89% for readings obtained after exercise. The test results also showed that there was unusual rising of the pulse rate after exercise; causing random beat per minute values. The developed system could be deployed for remote health monitoring applications in personal residences, hospitals, health centres and rural areas.

Abstract: Overheating have been attributed to the primary problem of continuous running induction motor in the industry. Star-delta control panels are equipped with protection devices against overcurrent and under/over-voltage but are not sufficient for protection against other temperature-producing fault conditions. This study aims to develop and integrate an IoT-based non-intrusive temperature monitoring and control system into a three-phase 30 h.p induction motor controlled by a star-delta panel. A two-stage temperature threshold limit for monitoring and control was setup at 45⁰ C, 60⁰ C below the 85⁰ C maximum operating temperature rating on the motor nameplate. The data entry collected for the two stages are 314 and 88 data points respectively. The results obtained for the two-stage setup showed that the normal operating temperature range between 30⁰ C to 40⁰ C for most of the operating time duration of the induction motor. Temperature anomalies of 45.5⁰ C and 85⁰ C were recorded for the first and second stage setup respectively. Shutdown of the induction motor was recorded for the first stage but not for the second stage which shows that the designed system responds differently to gradual and sudden temperature increase.