Arid Zone Journal of Engineering, Technology and Environment (AZOJETE)
Not a member yet
627 research outputs found
Sort by
Efficacy of Sugarcane Bagasse and Rice Husk Adsorbent for treatment of Heavy metals from petroleum refinery effluent
Get PDFHeavy metals are being extremely released into the environment due to poor was management resulting from industrialization and urbanization. Discharging wastewater contaminated with heavy metals poses a significant risk to human health and the surrounding ecosystem. Heavy metals are characterized by their non-biodegradable nature and potential carcinogenic properties. Activated carbons (ACs), which are carbon-based nano-porous adsorbents, are widely utilized in the removal of heavy metals because of their extensive surface area. In this study, active carbon materials were prepared using rice husk and sugarcane precursor by applying physical-chemical activation methods. To examine the Sequestering of heavy metals (cadmium, chromium, copper, lead, nickel, and zinc) in a refinery effluent, a batch adsorption technique was adopted, and the process parameter were investigated at different temperatures and impregnation ratio. Scanning Electron Microscope (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR) were used to determine the surface morphology and functional group while X-Ray Diffraction analysis (XRD) was used for the study of the crystallographic property of the activated carbon adsorbent. Both Rice Husk and Bagasse showed promising capacity for multiple adsorption of heavy metals. Freundlich and Langmuir's models were applied to study the sorption behavior. Although, process parameters play a vital role in the activation of the adsorbent, rice husk, and sugar bagasse have a strong potential for heavy metal adsorption. The hierarchy of performance effectiveness of rice husk was Cr>Pb>Cu>Cd>Zn>Ni according to the Langmuir model with Chromium (Cr) having the highest performance with a coefficient of correlation R2 of 0.9512 and the least Nickel (Ni) having R2 of 0.6156. While Sugarcane bagasse fitted well to the Freundlich model with the efficacy of removal in the order Pb>Cu>Cd>Ni>Cr>Zn with Lead (Pb) having the highest efficacy of removal with R2 of 0.957 and the least was Zinc (Zn) with R2 of 0.211 respectively. 
Performance Improvement of a Boost Converter Driving a Separately Excited DC Motor using Inductor-Capacitor (LC) Filter.
Get PDFThe increasing use of boost converter circuits for driving DC motors is attributed to their ability to provide extensive adjustable speed control, frequent starting, precise speed regulation, braking, and reversing capabilities. However, the presence of harmonic content poses a significant challenge for these converters. This study investigates the performance enhancements achieved through the integration of an Inductor-Capacitor (LC) filter in a boost converter circuit driving a separately excited DC motor. Simulation results demonstrate significant improvements in both converter and motor performance with the LC filter. The average output voltage and current of the converter increase from 122.61 V and 31.24 A to 129.30 V and 34.39 A, respectively, indicating effective ripple mitigation. Additionally, the motor speed rises from 1103 rpm to 1205 rpm, with corresponding improvements in efficiency for both the converter (from 81.21% to 94.18%) and the motor (from 68.32% to 85.13%) with the LC filter. These improvements highlight the critical role of the LC filter in reducing losses, enhancing motor performance, and achieving overall system efficiency gains. These findings highlight the significance of innovative filtering techniques in optimizing power electronics systems and motor control applications
The Study and Analysis of Cell Phone Charging Modules in Nigeria
No full textCellular phones require frequent charging with the aid of modules known as chargers. The performance of chargers in Oleh, a community in the Niger Delta area of Nigeria as a case study were investigated with a view to proffering solutions arising from the conventional act of disposing failed chargers without attempted remedies by users. Twenty (20) chargers were sampled and examined to determine the electronic components most likely prone to failure in the modules and possible reactivation. Also, experiments were performed to compare charging rates to initial specifications by manufacturers for the sampled chargers. The results show that the components most likely prone to failure from the sampled chargers in order of frequency of failure were circuit breakers, capacitors, switching rectifier and switching power transistors. Furthermore, one of the reactivated chargers model, Infinix of initial specification mostly available in Nigeria with open-circuit voltage of 5.00V and short-circuit current of 1500mA, recorded 4.50V, 800mA and was able to charge Samsung A12 phone to full capacity (100%) in twenty(20) minutes at a charging rate of 0.01V.min or -4.67A/min respectively. Similarly, reactivated Oraimo charger recorded 4.70.00V, 2500mA as against 5.00V, 900mA specifications when charging the Tecno Pop2 phone. The results show that the reactivated modules charging performances were comparatively enhanced at current delivery to loads as shown by the two cell phones. Therefore, it is recommended that Engineers and Technicians skills be chandelled towards local design and reactivation of failed charging modules in Nigeria.  
Environmental Trends Due to Arc Welding Activities: Sensitivity of some Typical Workplaces
No full textThe associated hazards with welding process are recently looked into because of the emission threat or lack or improper use of safety devices in work places relating to welding that could potentially lead to long- or short-term effect on worker and other staying nearby. This article provides data for various air quality parameters such as Total Volatile Organic Compounds (TVOC), Air Quality Index (AQI), Carbon Monoxide (CO), Carbon Dioxide (CO2), and Formaldehyde (HCHO) measured at different locations, North (N), West (W), East (E), and South (S) within Lagos Metropolis. The results of CO and HCHO levels are apparently higher than recommended limits in some locations (East and South) which suggest potential harm for workers as CO is mostly dangerous to health. However, other data suggests that air quality is generally good, as all AQI values are significantly below the break point of 50ppm. Further analysis revealed that at 95% confidence, there is no significant difference in the CO emissions patterns from different workshops as well as from different locations (North, West, East, and South) as Pvalue> 0.05. However, there is difference in CO2 as a result of change in locations as Pvalue (0.014) < 0.05. About 57.6% of the variability in CO2 emissions from various locations can be accounted for due to the variation resulting from change in location. The data thus provides useful information that could enable enforcement of personal protective equipment to ameliorate the situation.  
Integrating Bowtie Analysis into Band Saw Maintenance
No full textSawing machines used to cut raw materials to desired dimensions in industrial manufacturing operations are of great importance. Occupational injuries have occurred in the past as a result of failures in the risk management of these machines. In this paper, Bowtie analysis-based risk identification is developed based on the diagnosis of band saw cutting machine components. The results of the Bowtie risk assessment for hazards associated with the impeller, pump housing, saw blade, clamp, and seal pump were developed to structure the decision-making process with better information visualization. Hazards in the Bowtie were used to describe the root causes of failure (threats) that were identified, such as inadequate maintenance planning, foreign objects entering the pump, and inadequate maintenance. Based on the Bowtie diagrams, which capture the sufficient complexity of the real system behavior, the cutting tool was maintained following a corrective action plan that was developed. The assessment of the band saw performance rate after maintenance was 93%. This demonstrates that decision-makers can manage risk and reinforce a work culture that prioritizes actions to improve maintenance and safety outcomes using the Bowtie analysis method.  
A User Mobility Broadband Spectrum Aggregation Applications in LTE-Advance Heterogeneous Wireless Network Systems Using Real-Time Spectrum Selection Framework
Get PDFMobile user equipment can benefit from increased bandwidth and radio coverage of various access technologies through carrier aggregation and integration of heterogeneous networks. However, because of the mobility of user equipment, these technologies have increased the frequency of handoff scenarios, which results in low throughput and a high outage probability. In order to enable users to move between cells without losing connections, handover is an essential part of mobility management. However, no lone access mechanism can provide seamless and delay-free seamless interaction. As a result, the development of a suitable handover decision algorithm is necessary to ensure excellent service continuity and dependable user equipment access to the network at any location and at any moment. To confirm if various handover choice algorithms are effective in preventing communication failures and enhancing system performance. This research produced a mathematical model for the Real-Time Spectrum Selection Framework and Handover Decision Algorithm (RSSF-HDA). Additionally, mathematical models were extracted for comparison between the Multi-influenced Handover Decision Algorithm (MIF-HDA) and the Conventional Handover Decision Algorithm (Conv-HDA). A statistical comparative study was carried out using data from MTN drive-test readings at the Low-Cost housing estate located in Abesan, Ipaja, Lagos. According to statistical analysis results, the Real-Time Spectrum Selection Framework and Handover Decision Algorithm enhance system performance in terms of Cell edge Spectral Efficiency, and user throughput when compared with multi-influenced handover Algorithm and MTN field readings. For cell edge Spectral Efficiency at an average speed of 80km/s, RSSF-HDA gave a value of 1.52 bits/Hertz compared to MIF-HDA and MTN field readings with values of 1.37bits/Hertz and 1.33bits/Hertz respectively. For user throughput, inferred that there is no significant difference in readings of system throughput from the MTN field readings, MIF-HDA, and simulated RSSF-HDA which were 31%, 33%, and 34% respectively. 
Technological Capability of Selected Palm Oil Mills in Nigeria
Get PDFAn assessment of the technological capability of some modern palm oil mills in selected states of Nigeria (viz: Edo, Ogun, Ondo and Osun States) for production of special palm oil was carried out in this study. Information regarding the year of establishment of the mills, ownership of the mills, available facilities, production capacity and status of the mills (among others) were collected from the staffs of the mills. It was observed that government-owned mills (Okitipupa and Nigerian Institute for Oil Palm Research with capacities of 24 and 6 tons/hr, respectively) were in dilapidated condition and not functioning due to lack of proper maintenance. The mills had resulted into the utilization of intermediate technologies that can barely produce special palm oil and hence the huge investment in the mills has been wasted. In contrast, privately-owned mills (Okomu, JB and Royal Farm with capacities of 45, 8 and 3 tons/hr, respectively) which were also visited were functional. Two of them (Okomu and JB) were observed to have state of the art technologies for production of special palm oil and adopted well-arranged routine maintenance of the mills’ facilities. The study recommended that the existing public mills should be revived through public-private partnership system while privately-owned small-scale mills can be organized into groups such that they can acquire modern facilities for production of special palm oil. It is also recommended that there should be appropriate linkage between the mills and research institutes for sustainability
Performance Evaluation of a Hybrid Solar-Wind Power System for Heipang Community Load Demand
Get PDFThe electricity generation capacity of Nigeria, which is predominately fossil-based and unsustainable, is far below the energy needs of its growing population and industrial demand. There is a need therefore to increase the level of renewable energy in the energy mix to reduce the adverse effect of fossil fuels on the environment and enhance access to electricity. Assessing the performance of renewable energy systems in a location is a prerequisite for embarking on the technology. In this paper, 10-year average minimum solar radiation and wind speed data of the Heipang community of Barkin-Ladi LGA of Plateau State and load sharing strategy design approach were used to design a hybrid solar wind power system to meet the load demand of the Heipang community. MATLAB codes were written to simulate the designed hybrid solar-wind power system to assess its performance over the year against the given load demand profile using one-year hourly global solar radiation, wind speed, and ambient temperature data. Results show that for a load demand of 158.32 kW and a daily energy demand of 710.59 kWh/day, with two-day autonomy, it will require 283 units of 300W capacity solar panels, 2 units of 50 kW rated capacity wind turbine at 42m high and 90 units of 48V, 350Ah deep cycle batteries to meet the load demand. The capacity factors of solar, wind, and hybrid solar-wind power systems are 18%, 23%, and 21% respectively indicating high renewable energy resource potentials. The performances results also show slight complementarity between solar and wind power generation, thereby requiring battery backup to supplement the deficit
Generation of Rainfall Intensity-Duration Frequency Models for Port Harcourt City in South- South Ngeria
Get PDFInadequate meteorological data poses a significant challenge for engineers in accurately designing, operating, and planning water resources, particularly against extreme rainfall events. This study focuses on Generating Intensity Duration Frequency (IDF) Models for Port Harcourt City in South Nigeria. Daily rainfall data spanning thirty-two years (1983-2014) were collected from the Nigeria Meteorological Agency (NIMET) Oshodi, Lagos State. The annual maximum series method was employed to select datasets for rainfall analysis.
Two statistical distributions, Gumbel and Log Pearson Type III, were utilized to calculate observed rainfall intensity values at durations of 10, 15, 20, 30, 60, 120, 180, 240, 300, and 360 minutes, considering return periods of 2, 5, 10, 20, 50, and 100 years. Non-linear regression analysis using Microsoft Excel's Optimization Technique Solver wizard was performed to derive parameters for the IDF models for each duration and return period. Metrics such as chi-square (χ2), coefficient of determination (R2), and Root Mean Square Error (RMSE) were analyzed in order to assess the performance of the models. For the Gumbel distribution, R2 values ranged from 0.76 to 1.00, with RMSE from 0.20 to 11.73. The Log Pearson Type III distribution showed perfect R2of 1 and RMSE ranging from 0.23 to 9.68, indicating superior performance in terms of R2 and RMSE.
While there were no significant differences among the predicted intensities of various IDF models, the Log Pearson Type III Model is recommended for predicting rainfall intensities in Port Harcourt due to its superior performance metrics. These IDF Models serve as valuable tools for engineers and hydrologists in estimating stormwater runoff, designing drainage systems, managing reservoirs, and planning water resources development to mitigate flooding and its impacts. Moreover, they can enhance the teaching of land drainage courses for engineering students, providing practical demonstrations and improving their understanding of the subject matter.  
Development of Axle Load Spectra for Integration in Traffic Characteriaztion for Nigerian Empirical Mechanistic Pavement Analysis and Design Systems
No full textDesign traffic is employed in this research to estimate the expected load repetitions for a given axle load spectrum during the pavement life. In changing traffic characterization in mechanistic-empirical (M-E) design procedure, the process does away with the equivalent single axle load (ESAL) concept and traffic analysis implementation was done by directly using axle load. Comparison of predicted Number of Axle load range repetitions determined by equivalent axle load factor (EALF) and general axle load equivalency factors (GAF), is the main objective. In this study, axle load spectrum by Weigh-In-Motion (WIM) data and parametric standard axle loads which cause equal damage were collected and utilized. Determination of the axle load distribution factor (ALDF) from the WIM data. It is a critical input in the method based on different axle load groups for the estimation of the predicted number of axle load repetitions during the pavement design period. The results that the marked difference on the estimated predicted axle load predictions with the determination of EALF and GAF 63.95% of GAF value for SAST. Similarly, 10.14% for SADT; 30.24% for TADT and 21.43% for TRDT. This indicates the inherited error in the empiricism content in the empirical approach of handling traffic, for the determination of EALF. The estimated traffic prediction value increases as the captured axle load magnitude increased, as a resultant of the type of commodities and goods carried on the roadway pavement