East African Journal of Engineering

Distribution of Floods Frequency of Manafwa River, Uganda

2024-01-24T09:11:14+00:00

The objective of this study was to analyse Manafwa River flood frequency in Eastern Uganda. Analysis of Manafwa River maximum annual flows from 1949-2015 was undertaken using Log Pearson 3 distribution in comparison with Gumbel, Normal and Log Normal distributions to determine frequency of occurrence and magnitude of extreme floods. Statistical analysis including goodness of fit tests of chi-square, Kolmogorov-Smirnov and Anderson-Darling tests were used to generate the most suitable probability distribution model. The results show quantile magnitudes lowest for Log Normal distribution at 43.59 m3/s and highest for Log Pearson 3 distribution at 51.67 m3/s. The 5-year quantile estimates are highest for Normal and Log Pearson at 70.37 m3/s and 63.99 m3/s respectively. The 10-year quantile estimates are highest for Log Normal and lowest for Log Pearson 3 distributions at 87.57 m3/s and 75.13 m3/s respectively. The 100-year quantile estimates are lowest for Normal and highest for Log Normal distributions at 108.57 m3/s and 154.66 m3/s respectively. The 200-year quantile estimates are lowest for Normal and highest for Log Normal distributions respectively at 114.980 m3/s and 177.16 m3/s respectively. Log Pearson 3 distribution emerged as best fit for data. From the statistical analysis, LP 3 probability distribution presents the most accurate regression coefficient at 0.8486 and the most suitable distribution of goodness of best fit using A-D, K-S and Chi square tests followed by the Gumbel distribution. The tests yield 0.15666, 0.04855 and 0.88502 for A-D, K-S and Chi square tests respectively for the LP 3 distribution. There is an increasing upward trend of the discharges at Manafwa River floodplains at higher probabilities of exceedance across all the probability distributions due to varrying climatic changes and rapid landuse changes in the Manafwa catchment. Manafwa river floodplains have the capacity to accommodate and boost crop production and productivity. Any nutrients lost to leaching could be gained from subsequent fallowing and sustainable soil fertility management including; proper drainage, crop rotation, adding organic manure, cover cropping and among others

Analysing Bevel Gears for Efficient Power Transmission: A Study on Design, Simulation and Performance Assessment

2024-03-01T10:40:51+00:00

Bevel gears find application in transmitting motion between unequally aligned shafts, typically forming a 90° angle relative to each other. Some of the several types that are available commercially are the straight bevel, the Zerol bevel, the spiral bevel, and the hypoid. Stainless steel, gray cast iron, titanium alloy and structural steel were used for the behavioural assessment. The design and modelling of the straight bevel gears were carried out using SolidWorks 2015, while ANSYS 18.2 was employed simulating to simulate the gears' stress and deformation. The 3D solid model generated using SolidWorks was imported into ANSYS, where the analysis was conducted using the finite element software, ANSYS Workbench. Stress distribution plot, deformation plot, and equivalent strain plot were generated. The highest stress, measuring 73.536 MPa, became evident as the load concentrated near the base of the gear teeth. The finite element analysis revealed a minimal likelihood of gear failure, and the least deformation was observed in the structural steel configuration, resulting in a deformation of 8.2354 x 10^-3 mm. Consequently, the gear pair can successfully transmit 6 kW of power without experiencing any failures with a good safety factor

Level of Awareness on the Usage of Thermal Insulation among Building Professionals: Case of a Tropical City in Nigeria

2024-03-11T14:30:57+00:00

Adoption of buildings’ thermal insulation in Nigeria is still at the developmental stage; evidence of its usage for high thermal performance buildings and energy efficiency connotes a very low rate as there is very little evidence-based research in this regard. This paper seeks to evaluate the level of awareness on the usage of building thermal insulation among professionals in the building construction sector within Akure, a tropical city in Nigeria, to identify factors that deter its adoption and raise the level of commitment of the professionals within the building construction sector to sustainable practices of reducing buildings’ energy consumption. This is to create a resilient built environment against the challenges of climate change. Well-structured questionnaires were administered to gather data for the investigation. Jupyter Notebook version 6.4.12 was employed for the analysis. Results indicated a fairly good level of awareness among the building professionals while the barriers that affect the level of usage of thermal insulation within the study area are the high cost of procuring thermal insulation materials, non-compliance to building regulations, and governmental policy on construction. The research concluded that a good number of professionals have a high level of awareness of the usage of building thermal insulation, but the cost of the materials and government policy deterred its level of usage in the study area. Consequently, propagation of the usage of thermal insulation should be done through education and training of the stakeholders. Furthermore, the government needs to strengthen policies that support the usage and availability of thermal insulation within the study area

Development of Solar PV Assisted Dryer for Cooking Banana Slice and Analysis of Proximate Properties

2024-04-15T16:31:54+00:00

A solar PV-assisted dryer was developed for drying cooking banana and its performance tested. The proximate properties of the products dried in the solar PV-assisted dryer were compared to similar products dried using a laboratory oven, while open sun drying served as the control experiment. Fresh samples of cooking banana were obtained from a rural market in Ikot Akpaden, Mkpat Enin, Akwa Ibom State, Nigeria. The samples were subjected to peeling and cleaning before being sliced to a thickness of 5 mm. The dryer was embedded with a DC blower to enhance air circulation in the drying chamber. The blower was powered by a solar panel connected to a DC battery and a charge controller. 500 g of the product was loaded in the solar PV-assisted dryer, same as the other mediums. The moisture content was observed to have reduced from 67.32 to 5.80 % within 6 hours of drying as against 13 hours of open sun drying. The drying rate of the product decreased from 0.092 to 0.028 kg/hr in the solar PV-assisted dryer. The efficiency of the dryer was 40.6 %. Crude protein, crude lipid, crude fibre, and caloric value were lower in samples dried using the solar PV-assisted dryer and higher in samples subjected to drying in the laboratory oven and the control experiment. Ash content and carbohydrates were higher in products dried using the solar PV-assisted dryer than in other mediums. The study adds significant knowledge to the development of systems for post-harvest processing of cooking banana, a product highly sought for in the local market as a viable alternative to banana and plantain

Characterizing River Manafwa Floodplain and Adjacent Soils

2024-04-23T17:07:16+00:00

The objective of this study was to characterise Manafwa River floodplain and adjacent soils. Soil samples were collected from 0 - 20 cm depth in fallowed and cultivated Manafwa floodplain soils for laboratory analysis. Treatments included upland (control), floodplains fallowed for a year, floodplains fallowed for over a year, cultivated floodplains within 5 m and 50 m away from the river banks. Each treatment was replicated three times (3 blocks), and samples collected were analysed for K, Na, available P, total N, exchangeable acidity, pH, organic matter, moisture content, sand, silt, and clay. The soil sampling results were subjected to statistical Analysis of Variance (ANOVA) using Randomised Complete Block Design (RCBD), and the difference between treatment means were dictated using F-, student’s t and F-LSD/pairwise comparison tests. There was statistically no significant (p > 0.05) difference among different floodplains and uplands studied. Upland soils posted 71.67% for the highest pH and 0.09%, 0.87%, 9.74 ppm, 2.23 ppm and 7.264% for the lowest available N, organic matter, Phosphorous, Sodium and Moisture Content, respectively. Cultivated floodplain soil posted highest total P at 29.16 ppm and pH at 6.39% while fallowed floodplains lowest pH at 5.34%, highest available N at 0.32%, highest organic matter at 4.02%, highest K at 21.33%, highest Na at 13.93%, highest exchangeable acidity at 2.32 Cmol/Kg, highest clay content at 14.33%, lowest sand composition at 38.00%, highest silt composition at 54.8% and highest Moisture Content of 32.472%. As depicted by soil fertility analysis results, Manafwa River floodplain and adjacent soils have the capacity to accommodate and boost crop production and productivity. Any nutrients lost to leaching could be gained from subsequent fallowing and sustainable soil fertility management, proper drainage, crop rotation, adding organic manure, and cover cropping, among others