Umudike Journal of Engineering and Technology

Optical characterization of nanocrystalline Titanium dioxide (Tio₂) sensitized with natural dyes in the application of Dye Sensitized Solar Cells (DSSCs)

2023-10-31T06:33:51+00:00

This paper optically characterized nanocrystalline titanium dioxide (TiO₂ ) using natural dyes obtained from dacryodes edulis, mimosa pudica, delonyx regia and xanthosoma saggittifolium leaves to function as dye sensitizers in dye-sensitized solar cell (DSSC). Solvent extraction method was employed, UV-VIS spectrophotometer was used to obtain the optical absorbance spectra of the sensitized films while Tauc model was employed to determine the optical band gaps. From UV-Vis absorption spectra, ncTiO₂ sensitized with these natural dyes have absorbance at wavelength 200-720nm but low transmittance and reflectance in the visible region. This indicated that the dyes absorb visible light, which improves the optical properties of TiO₂ when sensitized with these natural dyes and have been found to be suitable for the use as sensitizers in solar cells. Also, their optical band gaps were obtained using Tauc relation, result showed approximate value of 1.30 × 10−9 eV.

Intelligent contactless IoT timer control system for electrical socket using wireless interface

2023-10-31T06:39:52+00:00

The conservation of energy is a significant problem that permeates every aspect of modern life. Over the course of the last few
decades, there has been an increase in the rate of power consumption as well as the costs associated with it. This growth is often
the consequence of excessively leaving electrical equipment on, even when they are not being used in the most effective manner.
Having the capacity to remotely turn on or off a socket or to remotely establish a time restriction for how long an appliance may be
powered on can both contribute to the reduction of energy use. This paper presents an internet of things (IoT) based timer controlled
electrical socket system that uses micro-controller and relays to automatically control the usage of electrical appliances. The system features an IoT remote controlled device that can be programmed to control the power outlet’s configuration, as well as real-time monitoring of the sockets status (either ON or OFF). This system can also be used to prevent overconsumption of energy and minimize the risk of electrical fires and accidental electrocutions. The system is developed with a wireless control web interface to enable the remote access to the controlled sockets. On evaluation, the proposed system presents an advantage to enhance energy usage and conservation.

Determination of quality index of packaged water obtained from two locations of Umuahia and Aba

2023-10-31T06:52:17+00:00

The quality of packaged water in Umuahia and Aba was studied using the water quality index (WQI) to determine their purity level. In particular, ten (10) parameters related to quality, viz pH, Turbidity, Electrical Conductivity, Total Dissolved Solids, Total Suspended Solid, Total alkalinity, Iron, Zinc, Chlorine, and Calcium were measured using appropriate measuring instruments. The WQI is computed from these parameters using the weighted arithmetic mean. The results show that the water quality index (WQI) values for Umuahia range from 8.06 to 303.7, implying that it covers the range between excellent water and that unsuitable for drinking. The qualities for Aba range from 33.85 to 91.28 signifying perfect water to good water status. The result also shows that 53% of water samples from Umuahia and 47% from Aba fall in the excellent categories, while 33% and 53% fall in the good water category. In addition, water samples from Aba are safe for consumption, while 7% of the samples from Umuahia are of poor quality and unfit for consumption due to their high electrical conductivity value. This investigation's outcome would assist manufacturers and policy managers in the measures needed to adjust the quality of packaged water for particular applications.

Development of the flow pattern map for the application of CO₂ gas in a three-phase downward flow

2023-10-31T09:06:40+00:00

The experimental modelling of a gas-liquid-liquid downward flow in a vertical pipe was performed to characterize the transportation of CO2 for further industrial application of the flow process. The study involved a multiphase downward flow pipe model integrated with a high-speed video camera to observe the flow patterns developed from the experimental proceedings of the flow process. This was achieved by varying the input flow rates of the CO₂ gas phase at high, medium and low set watercuts values of the liquid phases. These flow patterns were observed for 0.452 to 32.868m/s range of the calculated superficial velocities of the gas phase. The homogenous water and kerosene liquid phase was found between 0.452 to 32.868m/s 0.008 to 13.0734m/s at 20, 50, 70 and 90% water-cuts. Subsequently, the relationship between the area fraction occupied by the gas phase, the calculated superficial velocities of the gas and the homogenous liquid phases were utilised to empirically predict the transition criteria of one flow pattern to another for the developed flow pattern map of the studied flow system. These findings provide an adequate understanding of the industrial transportation, carbon capture and underground sequestration of CO₂ gas through a three-phase downward flow in the pipe; to meet the demands of emerging technologies.

Computational fluid dynamics analysis of a cross flow heat exchanger

2023-10-31T07:26:18+00:00

The paper presents the computational fluid dynamics analysis of a cross flow heat exchanger of hot Freon Fluid tube submerged in cold water domain. The simulation procedures were done for the two inlet velocities of the hot fluid at 0.015m/s and 0.035m/s; for a constant flow velocity of 0.02m/s for the cold water. The result of the temperature distribution showed a decrease from 305 to 301.69K and 305 to 302.44; and an increase from 300 to 301.75 and 300to302.45 for the hot Freon and cold water fluids respectively. The logarithmic mean temperature difference (LMTD) value for the two inlet velocities of hot Freon fluid were evaluated to be 2.71K and 2.68K; consequently, the required operating average temperature difference of the flow system for the two fluids was established to be 2.70K; while the effectiveness was determined as 89%.Further, the analysis revealed a constant pressure distribution across the water plate, while the Freon fluid increased from 1 to 1.77atm across the tube length. The velocity distribution showed that the cold water velocity increased rapidly around the horizontal and angled orientations of the Freon tube from 0.02 to 0.15m/s; while that of the hot Freon fluid remained constant across the tube length. This change in velocity was attributed to the high rate of heat exchange rate at those sections of the Freon tube. The findings from this study will be used to enhance the design and performance evaluation of heat exchangers to meet future technological demands.

Optimizaion approach for evaluation of mechanical properties of high pressure die cast aluminum alloyed product

2023-10-31T07:33:07+00:00

This work produces a machine component-motor cycle hand clutch using a high pressure cold chamber die casting machine. The aluminum cable coil was alloyed with 10%wt silicon and 0.6%wt of magnesium and 0.5%wt of copper while the chemical composition of aluminum alloyed coil contains 97.82% aluminum, 1.17% of silicon, 0.54% of copper 0.35% magnesium, and traces of iron and chromium. Taguchi method was adopted for optimization of the response parameters and mechanical properties of the cast to obtain the optimum performance of porosity using density as response factor. The optimal value was obtained with sample specimen 3 with charging masses of Si = 0.7; Cu = 0.8 and Mg = 0.7 at density of 2.7533 and porosity of 0.3632, while at this optimal value, the following corresponding values for mechanical properties were obtained: impact = 136/416 Joules; UTS = 58.487 N/mm² ; Hardness = 41HRB, %Elongation = 11.3649; Y.M = 882.3998; Flexural Strength = 105.9556 N/mm2 with a yield strength of 2.0763 N/mm².

Shea butter oil transesterification via clay doped barium chloride catalyst; response surface methodology and genetic algorithm evaluation

2023-10-31T08:11:43+00:00

A novel clay-doped BaCl (CD-BaCl) heterogeneous catalyst was developed through calcinations at 600oC for four hours and successfully applied for biodiesel production from shea butter oil. The catalyst was characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Micrograph (SEM), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), and BrunauerEmmett-Teller(BET) before and after treatment to ascertain its suitability for the process. The shea butter oil was characterized using FT-IR and GC-MS (Gas Chromatography Mass Spectrometer) to confirm its potential for the transesterification process. Response surface methodology (RSM) and Genetic Algorithm (GA) were used to compare the best operating conditions; GA outperformed RSM with a biodiesel yield (81.49%) obtained at a catalyst loading (3 wt%), methanol/molar ratio (12:1 mol/mol), time (3 hours), temperature (50^oC), and agitation speed (208.8 rpm). The second-order polynomial model is shown in the (Analysis of Variance) ANOVA with an R² value of 0.9981, Adj R² (0.9946), and Pred R² (0.9499), demonstrating the model's acceptance. The shea butter biodiesel produced complied with ASTM D6751 requirements. As a result, this study showed that GA is more predictive than RSM.

Determination of some physical properties of African oil bean kernel relevant for design of the processing machine

2023-10-31T08:56:57+00:00

This study investigated some physical properties of African oil bean kernel such as size, sphericity, surface area, bulk density, true density, weight, porosity, volume, angle of repose and the coefficient of friction on various material surfaces. Standard methods from the literature were adopted in carrying out the experiment. The properties were investigated at moisture content of 14.63% wet basis. The results obtained showed that the average values of major, intermediate and minor diameters of the kernels were 47.34, 30.13 and 9.99 mm, respectively. The volume, sphericity, porosity, surface area, bulk and true densities were obtained as 23.34cm³ , 0.51, 45.23 %, 18.45 cm² , 0.64g/cm³ and 0.85g/cm³ , respectively. The coefficient of friction of the kernels on wood, glass and metal were gotten as 0.88, 0.72, and 0.77, respectively while the angle of repose is 14.57^o . The data obtained will be useful in the design of postharvest machines for African oil bean kernel.