DEPARTMENT OF THE MECHANICAL ENGINEERING

The development of affordable and efficient vacuum cleaners has become a significant concern for households and small-scale cleaning businesses, especially in developing regions where high-end vacuum cleaners are often too expensive. Vacuum cleaners are essential tools in maintaining clean indoor environments by removing dirt, dust, and other debris from floors and surfaces. However, the design and functionality of many low-cost vacuum cleaners are often compromised, especially in terms of air velocity, particle retention, and the efficiency of dust separation. These issues can lead to ineffective cleaning and the release of fine dust particles into the environment, undermining the overall effectiveness of the vacuum cleaner. Previous designs of vacuum cleaners fabricated from locally available materials often suffer from limitations such as inadequate air velocity through the wand, improper filtration of fine particles, and ineffective dust deposition mechanisms. These flaws not only reduce the cleaning efficiency but also compromise air quality in the environment. This study aims to review and improve upon the design and fabrication of such vacuum cleaners, addressing these critical issues to enhance performance and dust control.

Coconut is a cash and food crop that has the abaility to be grown even in bad weather, hence can be cultivated around all weathers and in virtually any geographical location in Nigeria. However; there are growing concerns of its judicious and profitable cultivation and post-harvest processing despite its commercial value as it can be consumed as food and its constituent parts can be used in pharmaceuticals, beverages, energy and power and a host of other products such as brooms, mats, floor mats. Prior to its use the coconut fruit is dehusked to remove its outer fiber shell. The dehusking process which conventionally involves the use of human effort using a sharp object is characterized by low output, susceptibility to injury and unhygienic nature. To mitigate these setbacks, a coconut dehusking machine was designed and fabricated using the design Methodology of reverse engineering. The machine had some components which include hopper, twin shafts with dehusking spikes, pulleys and pulley belts, bearings and a structural rame. Test and operational performance carried out on the machine showed that it was quite effective for dehusking various sizes of coconuts with a throughput capacity of 33 coconuts per hour. The efficiency of the machine was estimated as 83.3%. Effectiveness of the dehusking process was dependent on the dehusking force of the machine and the moisture content of the coconut fiber. A major advantage and achievement in this prototype was that more than one coconut could be dehusked simultaneously and the dehusked coconuts can be discharged automatically without the input of human effort.

To understand the popularity of electric vehicles circa 1900, it is also important to understand the development of the personal vehicle and the other options available. At the turn of the 20th century, the horse was still the primary mode of transportation. Steam emerged as a reliable energy source with a proven track record, notably powering factories and locomotives. In the late 1700s, steam also played a role in some of the earliest self-propelled vehicles. However, despite its early adoption in various applications, it wasn't until the 1870s that steam technology began to gain traction in the automotive industry. One significant reason for the delayed adoption of steam technology in cars was its impracticality for personal vehicles. Steam-powered vehicles faced several challenges that hindered their widespread use. For instance, they required considerable startup times, often up to 45 minutes, particularly in cold conditions. Additionally, steam vehicles needed frequent refilling with water, which imposed limitations on their range and practicality for everyday use. These drawbacks underscored the challenges associated with steam-powered cars and contributed to their eventual decline in favor of alternative propulsion methods, such as internal combustion engines and electric motors, which offered greater convenience and efficiency for personal transportation. As electric vehicles came onto the market, so did a new type of vehicle, the gasoline-powered car thanks to improvements to the internal combustion engine in the 1800s. Although gasolinepowered vehicles had potential, they were not without problems. They took a lot of human labor to operate because shifting gears was a difficult operation, and starting them required turning a hand crank, which some drivers found challenging. Gasoline-powered vehicles were also notorious for their noisy engines and nasty exhaust. (TOTAL ENERGIES, 2020) In contrast, electric cars did not suffer from the issues associated with steam or gasoline vehicles. They were quiet, easy to drive, and did not emit the noxious pollutants characteristic of other cars of the time. Consequently, electric cars rapidly gained popularity among urban residents, particularly women. They proved ideal for short journeys within the city, especially considering the poor road conditions outside urban areas, which limited the travel range of all types of vehicles. (Nilesh Wani, 2020)

With the rising need to maximize passenger’s comfort, especially with the rising demand for selfdriving vehicles, alternatives to the popular passive suspension system have been on the rise. In order to improve the stability of a vehicle and reduce the vibration transferred to the passengers of the vehicle due to different road profiles, it has become necessary to implement a smarter type of suspension system that can respond to different type of road profiles and provide improved damping experience. This type of suspension system is the active suspension system. In order to analyze and simulate an active suspension system, parameters like the sprung and unsprung mass, spring and tire stiffness, damping constant of the damper were accounted for. Then the mathematical model of the system in the time domain was generated. Mathematical model was transformed from the time domain to frequency domain, using the Laplace transform. Then an appropriate controller for stabilizing the system was obtained. The simulated results show that the active suspension system performs better than the passive suspension in terms of settling time, rise time and overshoot and had lesser vibrations was transmitted to the passengers

This systematic review examines the effectiveness and feasibility of heating and ventilation systems as critical interventions to mitigate substantial post-harvest maize losses in Nigeria, which currently range from 20% to 30%. The core challenge stems from Nigeria's humid, tropical climate, where high temperatures and relative humidity foster pest infestations, microbial growth, and the dangerous production of aflatoxins by Aspergillus species. The study finds that uncontrolled heat, particularly in structures like metal silos, encourages harmful moisture migration and spoilage , while controlled heating remains a potential solution for active grain drying. Ventilation is identified as the key defense mechanism, but its implementation is complicated: traditional natural airflow systems often fail in the humid southern regions, and powered aeration faces significant constraints due to high ambient humidity and an unreliable electricity supply. The analysis concludes that a universal, one-size-fits-all approach to technology dissemination is inappropriate. Success depends on context-specific technology recommendations tailored to Nigeria's distinct agro-ecological zones, differentiated by production scale, and supported by complementary institutional capacity development. There is an urgent research and innovation gap in developing affordable, intelligent ventilation systems specifically designed for local climate zones. Furthermore, successful adoption relies on coupling technology promotion with market development strategies that enable farmers to realize economic premiums for improved grain quality.

This study presents the design, modeling, and simulation of a dual-shaft plastic shredder for recycling polyethylene terephthalate (PET), high-density polyethylene (HDPE), and low-density polyethylene (LDPE) waste. The research addresses the challenge of plastic pollution in Nigeria through a simulation-driven engineering approach that eliminates costly physical prototyping.
Using SolidWorks 2025 for computer-aided design (CAD) modeling and finite-element analysis (FEA), a comprehensive digital prototype was developed and validated. The shredder features two counter-rotating 50 mm diameter EN8 steel shafts with 32 AISI D2 tool steel blades, driven by a 2.2 kW three-phase motor operating at 120 rpm. Design specifications target a hroughput
capacity of 40–60 kg/hr with output flake sizes of 10–15 mm.
Validation was performed through three complementary methods: mesh convergence analysis confirmed solution independence with less than 4.2% variation in maximum stress; analytical validation using classical beam bending and torsion theory yielded results within 11.7% of FEA predictions (analytical: 132.3 MPa; FEA: 148.2 MPa); and mesh quality assessment confirmed
computational reliability with Jacobian ratios between 1.0 and 4.982. Simulation results demonstrate structural integrity with a maximum Von Mises stress of 148.2 MPa (33% of EN8 steel yield strength), negligible shaft deflection of 0.003 mm, and a minimum factor of safety of 3.2, exceeding the design requirement of 2.0 by 60%. The study successfully demonstrates that computer-aided simulation can produce reliable, optimized recycling machinery designs suitable for local fabrication, contributing to sustainable waste management solutions in developing economies.

Mooring systems remain one of the most critical safety components in marine operations, yet failures continue to occur across ports and offshore environments. These failures often lead to equipment damage, operational disruptions, and, in severe cases, loss of life. This study investigates the major causes of mooring system failures and evaluates the associated risks, with a particular focus on mooring practices in port environments. The research combines a detailed review of mooring system fundamentals with an assessment of human, environmental, and equipment-related factors that influence failure. A structured questionnaire was used to obtain first-hand information from marine professionals, and the responses were analyzed using the Failure Mode and Effects Analysis (FMEA) technique. The findings reveal that human error, inadequate inspection routines, worn mooring lines, and environmental forces such as strong winds and currents are leading contributors to mooring failures. Several failure modes were identified, but the highest Risk Priority Numbers (RPNs) were associated with poor maintenance culture, deviation from safety procedures, and the use of degraded lines. These areas represent the most urgent risks requiring intervention. The study also highlights gaps in compliance with standard mooring system management practices, including inconsistent adherence to the Mooring System Management Plan (MSMP). Based on the results, the research recommends stricter enforcement of mooring safety procedures, regular condition monitoring of mooring equipment, improved crew training, and the adoption of structured risk-assessment tools such as FMEA during operations. Strengthening these areas will significantly reduce the likelihood of failures and enhance the overall safety and reliability of mooring operations in Nigerian port environments.

This study investigates the technology employed in the production of Type 4 Liquefied Petroleum Gas (LPG) composite cylinders and explores potential improvements to enhance their performance, safety, and cost-effectiveness. Type 4 cylinders, composed of a polymer liner fully wrapped with fiber-reinforced composites, represent the most advanced generation of LPG storage vessels due to their lightweight structure, corrosion resistance, and superior burst strength. Data for the research were obtained through field observations at Don Mac Limited, review of standard operating procedures (SOPs), and engineering simulations. The study analyzed each stage of the production process—from liner molding and surface preparation to filament winding, curing, testing, and inspection—based on ISO 11119-3 and EN 12245 standards. Simulation results revealed that substituting high-density polyethylene (HDPE) liners with polyamide (PA11) and E-glass fibers with hybrid carbon–glass reinforcements increased burst pressure from 50 bar to 70 bar while maintaining a high factor of safety.

This project presents the design and fabrication of a system capable of reheating food and maintaining its temperature. Heat was generated by converting the electrical energy derived from both the Alternating Current (A.C) and Direct Current (D.C) source. The A.C circuit consisted of a heating element of 220V, 1kW power rating, and an electrical outlet a thermocouple and a temperature controller; the D.C circuit consisted of a mobile filament of 6V, 55W power rating, a dry cell D.C lead battery of 12V and 18Ah a thermocouple and temperature controller. A cup of water, meat pie, and a bowl of cooked rice was used to test the system’s performance and the set temperature was 60 degrees (ºC). At the end of the A.C experiment, it took the system approximately 7 minutes to reach the set temperature in the case of water, 7 minutes for the meat pie, and 6 minutes for the cooked rice. Due to heat transfer conditions, the food overheated; the water reached a maximum temperature of 83 degrees and the meat pie reached a maximum temperature of 81 degrees (ºC). The time taken for the food to reach the set temperature value after heating was approximately 45 minutes. At the end of the D.C experiment, it took the system approximately 22 minutes to reach the set temperature in the case of water, 20 minutes for the meat pie, and 21 minutes for the cooked rice. Due to heat transfer conditions, the temperature of the food increased further; the water reached a maximum temperature of 70 degrees, the meat pie reached a maximum temperature of 66 degrees (ºC), and the cooked rice reached a temperature of 68 degrees. The time taken for the food to reach the set temperature value after heating was approximately 23 minutes.

As global energy demands continue to rise, the search for alternative and sustainable energy sources has become a critical area of research. According to the International Energy Agency’s (IEA) New Policies Scenario, global electricity demand is projected to increase by approximately 80% between 2012 and 2040 (Elhalwagy et al., 2017). This growing demand, coupled with environmental concerns related to fossil fuel consumption, has driven significant interest in renewable and clean energy technologies. Among the various emerging energy solutions, piezoelectric energy harvesting has gained attention as a promising approach to generating electricity from everyday human activities, such as walking. Piezoelectricity refers to the ability of certain materials to generate an electrical charge when subjected to mechanical stress. This phenomenon is particularly useful for harvesting energy from human movement, specifically footsteps. Footstep power generation utilizes piezoelectric materials embedded in floors to convert kinetic energy into electrical energy. In high-footfall areas such as train stations, shopping malls, pedestrian walkways, and university campuses, the cumulative energy generated from footsteps can be significant (Elhalwagy et al., 2017). If effectively captured and stored, this energy could power small electronic devices, lighting systems, and digital displays—contributing to sustainable urban infrastructure.