SciengtexOpen Journal System
Not a member yet
112 research outputs found
Sort by
Comparative assessment of the phytochemicals of the leaves and seeds of pigeon pea (Cajanus Cajan (L.) Huth) plant
Get PDFThe pigeon pea plant is one of the plants cultivated in the semi-arid tropics; it is widely cultivated in Nigeria. It is utilized as food and serves medicinal purposes. This study was carried out with the aim of assessing the phytochemicals. Pigeon pea leaves and seeds were purchased from farmers in Uromi, Edo state, and Rumugbo phase-2, Obia Akpor Local government area of Port Harcourt, Nigeria. The phytochemical components of both the fresh and dried leaves and seeds were determined using the standard method and the results obtained from this study showed that in both the fresh and dried leaves of pigeon peas alkaloids, flavonoids, terpenoids, steroids, phytosteroids, saponins, tannins, phenol, anthraquinones, quinones, xanthoproteins, and phlobatannin were detected while the acidic compound was absent. While in the fresh and dried seeds of pigeon pea, results obtained revealed that alkaloids, flavonoids, terpenoids, steroids, phytosteroids, saponins, anthraquinones, and quinones were present while tannins, phenol, xanthoproteins, phlobatannin, and acidic compound were absent. Phytochemical compounds of the ethanolic extract of the fresh and dried leaves and seeds of pigeon peas were determined using Gas Chromatography - Mass Spectroscopy and a total of 30, 13, 32, and 38 bioactive constituents were detected in the fresh leaves, dried leaves, fresh seeds, and dried seeds respectively using their retention times (RT) and mass-to-charge ratios (m/z)
The Effects of Plastic Waste Materials on the Physical and Strength Properties of Floor Tiles
Get PDFHuman activities often generate solid waste, such as plastics. The disposal of this waste is usually a setback. This paper aimed to examine the viability of using plastic waste and white cement to produce floor tiles. Waste was collected from waste disposal facilities within Benson Idahosa University. The materials were cleaned and dried, and plastics were shredded. Waste materials were then mixed with white cement in different ratios. Compressive strength tests were performed to verify the suitability of utilising these solid wastes to make floor tiles. Shred plastics that were passed through a sieve with an average diameter of 1 to 2 mm were utilised. The cubes were cast and cured for 7, 14, and 28 days. The compressive strength of the cubes was tested using a universal testing machine. The study found that the addition of up to 50 % of cement resulted in a more than a 10-fold increase in the compressive strength of the cast cubes. On the other hand, the inclusion of plastics reduced the compressive strength of the cubes. Furthermore, increasing the number of plastics increased water absorption, whereas larger amounts of cement reduced water absorption. Plastics are a common waste produced by man; hence, they are easily accessible and a very economical material to produce floor tiles
The Effect of Metal Inert Gas Welding Parameters on the Weldability of Galvanised Steel
Get PDFThe Taguchi technique is employed to establish the optimal parameter for each tensile property of the weldments. The tensile properties determined are the ultimate tensile strength, the yield strength, and the percentage elongation, whereas the process parameter used is the welding current (A), welding voltage (B), and the gas flow rate (C). By applying the Taguchi method, the optimal process parameters for obtaining the weldment with better yield strength are A3B1C3, whereas A3B3C3 can produce the weldment for better elongation. These optimum process parameters have shown considerably improved signal-to-noise ratios over the current process parameters adapted by the welders
Leaching of Ibute-Nze kaolin iron-oxide impurity with oxalic acid process optimization of dissolution conditions using response surface methodology
Get PDFThe goal of this research was to remove iron oxide from Ibute-Nze kaolin by dissolving the clay mineral in an aqueous oxalic acid solution and optimizing the process. The chemical composition of the raw and modified clay was determined using x-ray fluorescence, and the morphology of the solid sample was determined using a scanning electron microscope. The best conditions for the oxalic acid leaching of iron-oxides impurity from Ibute-Nze kaolin were determined using response surface methodology based on Box-Behnken design. The studies were carried out within the following process parameter ranges: 40–90 leaching temperature; 0.075-0.355mm particle size; 1–6 mol/dm3 acid concentration; 0.02–0.12 g/cm3 kaolin sample to acid ratio and 30-240 min contact time. The characterization revealed that Ibute-Nze clay is kaolinitic in nature and calcination at 750 opens more pores for its leaching. According to the analysis of variance, a second-order polynomial regression equation provided the best fitting for the experimental data. The predicted and experimental response values were shown to be correlated (R2 = 0.9276) in the experimental runs. The following were found to be the best conditions for the leaching process variables: 83.2051 leaching temperature, 0.0827mm particle size, 3.6179mol/dm3 acid concentration; 0.0287g/cm3 kaolin to acid ratio and 217.932min reaction time. The chemical leaching process was 92.6035 per cent under these conditions, which made the clay good for industrial applications
Non-linear bending and stress analysis of a transversely loaded isotropic plates material using 3-D plate theory
Get PDFThis paper presents the bending stress analysis of anisotropic plate material under transverse loading using a three-dimensional (3-D) plate theory. The static elastic theory was used to formulate the total energy expression of the plate thereafter, transformed into a compatibility equation through general variation to get the slope and deflection relationship. The solution of equations of the equilibrium gave rise to the exact polynomial deflection function while the coefficient of deflection and shear deformation of the plate was gotten from the governing equation through the direct variation method. These solutions were used to obtain the characteristic expression for analyzing the displacement and stresses of the rectangular plate. This formula was used for the solution of the bending problem of the rectangular plate that is clamped at the first-two edge and the other edges simply supported (CCSS). The result of the deflection and stresses decrease as the span-thickness ratio increases. More so, the aspect ratio effect of the shear stress of isotropic plates is investigated and discussed after a comparative analysis between the present work and previous studies. The result shows that the present study differs from that refined plate theory (RPT) of assumed deflection by 5.5% whereas exact 2-D RPT by 5.3%. This shows the efficacy of the exact 3-D plate theory for flexural characteristics of CCSS isotropic rectangular thick plate
Microgrid, Its Control and Stability: The State of The Art
Get PDFSome of the challenges facing the power industries globally include power quality and stability, diminishing fossil fuel, climate change amongst others. The use of distributed generators however is growing at a steady pace to address these challenges. When interconnected and integrated with storage devices and controllable load, these generators operate together in a grid, which has incidental stability and control issues. The focus of this paper, therefore, is on the review and discussion of the different control approaches and the hierarchical control on a microgrid, the current practice in the literature concerning stability and the control techniques deployed for microgrid control; the weakness and strength of the different control strategies were discussed in this work and some of the areas that require further research are highlighted
Design and implementation of a fingerprint-based biometric access control system
Get PDFSecurity systems are often penetrated by sophisticated criminals, thus there is always a need for new solutions to be devised to give sufficient security to houses and other locations. The goal of this project is to build and deploy a fingerprint-based biometric access control system. The fingerprint is a pattern of ridges and valleys on the surface of a fingertip. Among various biometrics, fingerprint recognition is the most extensively and internationally accepted biometric because of its uniqueness, accuracy, cost-effectiveness, non-transferability, and ease of use. Presented is the system architecture for the system development that demonstrates component augmentation, detail extraction, and matching methodologies. MATLAB and the programming language C were used to develop a software application that was used to build algorithms for improvement, minutiae extraction, and matching processing. The software works by extracting meaningful features known as minutiae points from the person’s fingerprint, then records and stores these minutiae points to verify the person’s identity in the future. The resulting minutiae information is used to find matching fingerprints and to register these fingerprints in the system database. Finally, a verification system and identification system were realized. The proposed automatic door access control system was implemented using the Arduino Atmega 328p microcontroller. The proposed system was tried-out in real-time, and its performance was deemed adequate
Design and simulation of an effective backup power supply for academic institutions in Nigeria: A case study of NDA postgraduate school
Get PDFThis research work is aimed to mitigate the adverse effect of numerous portable generators used in academic environments due to the unstable power supply experienced in Nigeria. Data for the study on the existing backup, availability hours from the national grid, and load demand for the area of study were obtained from the residents of the campus, facility managers, and Kaduna Distribution Company as the grid supplier from August 2017 to December 2020. The average load of the campus was obtained to be 80kW. These were used as a baseline to obtain the required size and quantity of material to generate the backup power needed. A total ampere-hour requirement of the battery to be used was obtained to be 4,278.07Ah considering the average battery depth of discharge of 80%. This resulted in a total number of cells required to be 134 considering a battery with a 200Ah rating and a nominal voltage rating of 48V. A solar photovoltaic (PV) system rating of 166.4kW is required to sufficiently charge the battery bank and also serve the load. This amounts to a minimum of 5 panels per string connected in series and 34 number panels per string connected in parallel based on which the total number of panels required summed up to 666. The inverter rating for the load was obtained to be 150 kVA with a total load of 100 kVA, an efficiency of 80%, and an average future expansion of 20 %. A diesel generator rating of 100kVA with a starting kVA rating of 113.64kVA is required to efficiently serve the load considering future expansion of 1.1 and operating efficiency of 80 %. These obtained parameters were simulated using MATLAB/Simulink to test the feasibility of the backup systems. The generation cost of each backup was calculated based on which solar PV with battery bank has an initial energy generation cost of 81.9 ₦/kWh and a future energy generation cost of 0.27 ₦/kWh while diesel generator has an initial energy generation cost of 1602.04 ₦/kWh and a future energy generation cost of 8.07 ₦/kWh as such, PV has the least energy cost and more economical for the academic environment
A Rough Set Approach to Dimensionality Reduction for Performance Enhancement in Machine Learning
No full textMachine learning uses complex mathematical algorithms to turn data set into a model for a problem domain. Analysing high dimensional data in their raw form usually causes computational overhead because the higher the size of the data, the higher the time it takes to process it. Therefore, there is a need for a more robust dimensionality reduction approach, among other existing methods, for feature projection (extraction) and selection from data set, which can be passed to a machine learning algorithm for optimal performance. This paper presents a generic mathematical approach for transforming data from a high dimensional space to low dimensional space in such a manner that the intrinsic dimension of the original data is preserved using the concept of indiscernibility, reducts, and the core of the rough set theory. The flue detection dataset available on the Kaggle website was used in this research for demonstration purposes. The original and reduced datasets were tested using a logistic regression machine learning algorithm yielding the same accuracy of 97% with a training time of 25 min and 11 min respectively
Design and Hybrid Simulation of a Larceny Deterrent Energy Evaluation System
Get PDFThe unreliability of the energy system to provide a proper account of energy utilized by consumers has been a huge burden on the distribution system network. Different metering methods and designs to detect and prevent fraud, employed in the past have proven fruitless, thus signalling the need for a much smarter energy metering system. The most frequent problem is electricity larceny, this has incurred a major economic loss in the energy distribution system. To this end, this paper presents the distinctive design and hybrid simulation of a larceny deterrent energy evaluation system, capable of detecting different methods of energy theft within power consumer premises. The method employed comprises of deep understudy of previous work in this field, a model is proposed and is simulated under good working conditions and several theft situations using MATLAB while the hardware is simulated using Proteus 8.1 and Arduino software. In conclusion, the efficiency of the proposed system is evaluated by employing different electric theft algorithms, with the results indicating significant energy cost savings in the distribution network