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Papers by kennedy owuama

Journal of Engineering Sciences

The effect of the hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants on the ... more The effect of the hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants on the environment through the attack of its halogen contents-chlorine and fluorine, on the ozone layer and the toxic nature of such refrigerants, has paid the attention of researchers to work towards getting suitable alternatives using hydrocarbons (HC) or its blends with HFC refrigerants. This study was centered on getting a suitable retrofit of R-134A with a good coefficient of performance (COP) and low global warming potential (GWP) using the blends of R-290 and R-600 HCs for use in refrigeration systems. An experimental testing rig was developed by assembling various measuring devices to the operational points of a vapor compression refrigerator. A mixture design was developed using the simplex lattice design (SLD) of design expert software 11.0. The response variables considered were COP and GWP. The experimental design was meticulously followed using 1kg for each refrigerant run, and the...

Heliyon, 2021

The utilization of various feedstocks of unique characteristics in producing biogas could potenti... more The utilization of various feedstocks of unique characteristics in producing biogas could potentially enhance the application of clean fuel from biomass wastes. Two modelling tools were used to explore biogas production from plant and animal wastes. In this study, corn chaff was inoculated with cow dung digestate using different mixing ratios of substrate/inoculum (S/I) of 1:1, 1:1.55, and 1:3.5 for hydraulic retention time (HRT) of 25, 31, and 37 days as modelled using Central Composite Design (Face Centered Design) to optimize the process and predict the optimal response. The result shows that the mixture ratio of 1:1.55 for 37 days gave a cumulative highest biogas yield of 6.19 L under mesophilic conditions. The model p-value is <0.0001, an indication that the model term is significant. The python coding of the input factors gave the optimal value of 4.71 L, which is similar to the result obtained via CCD. Thus, both CCD (Face Centered Design) and python coding are reliable in the optimization of biogas production as they both predicted the same optimal values and approximately the same highest cumulative biogas yield. The GC-MS characterization of produced biogas revealed that it contains 68% methane and 22.76% CO2. Other constituents present are confirmed by FTIR analysis results. The methane in produced biogas has a flashpoint of -182 °C, which is extremely flammable. This data shows that both CCD and python coding can model biogas production with high accuracy and biogas produced can be used for heating purposes.

Journal of Energy Research and Reviews, 2020

Human Life on earth is driven by energy and with the global challenge on best ways to manage wast... more Human Life on earth is driven by energy and with the global challenge on best ways to manage waste, there is need to convert organic waste to bioenergy which will help reduce the rate of environmental pollution and over dependence on conventional source of energy. In this investigation maize chaff were inoculated with cow rumen using different concentration ratios (S/I) of 1:1, 1: 1.55, 1:3.5 for 25, 31 and 37 days Retention Time (RT) as design by Central Composite Face Centered Design to optimize the process and predict the best response. The result obtained shows that the mixture ratio of 0.65 (1:1.55) for 31 days gave the optimum yield while 0.65 mixing ratio for 37 days gave the maximum yield at 0.42L under mesophilic (20°C to 45°C) condition. The Flash point of the cummulative maximum yield was -164°C which is really flammable. The model F-value is 95.03, p-values is < 0.0001 which is less than 0.05 and both values indicate model terms are significant. Lack of Fit F-value of...

23 www.wjir.org  AbstractThe optimization of dry compressive strength of groundnut shell ash (GS... more 23 www.wjir.org  AbstractThe optimization of dry compressive strength of groundnut shell ash (GSAp) and ant hill powder (AHp) was investigated. Ratio of: 2/0, 4/5, 6/10, 8/15, 10/20, 12/25, 14/30% GSAp/AHp was used in the formulation. Taguchi method was used to determine the optimization condition. The work shows that the maximum baked compressive strength of 356.7, 355.0, 335.3 kN/m 2 was obtained at 5, 2, 1h and 100, 200, 300 o C at 14/30% GSAp/AHp addition. GSAp/AHp has the greatest effect (97.61%), followed by time (2.03%) and the least temperature (0.35%). The shear strength of 78.12, 110.00, 123.00, 145.60, 154.67, 158.90 and 168.9 kN/m were obtained at 2/0, 4/5, 6/10, 8/15, 10/20, 12/25, 14/30% GSAp/AHp respectively. The optimal condition for the dry compressive strength for the selected factors and levels was achieved at GSAp/AHp level L3, time L2 and temperature L1. At optimum quantities of GSAp (14%) and AHp (30%) added to silica sand, the results obtained showed that gro...

Journal of emerging technologies and innovative research, Oct 1, 2021

Inhibitive effect of Dennettia tripetala (DT) (pepper fruit) extract on corrosion of aluminum in ... more Inhibitive effect of Dennettia tripetala (DT) (pepper fruit) extract on corrosion of aluminum in 0.5 M H2SO4 medium was investigated. The pepper fruits were obtained from Egbudu market, Warri and was processed to powder. Phytochemical analysis was carried out using quantitative and qualitative methods respectively. Fourier Transform Infra-Red (FTIR) spectroscopy was carried out to determine the functional groups of the phytochemicals. Gravimetric (weight loss) and electrochemical techniques was used for the corrosion study within a temperature range of 303 to 323K. The results from the phytochemicals analysis revealed the presence of alkaloids, flavonoids, phenols, saponins, tannins, steroids, phytates and glycoside. The gravimetric studies revealed that inhibition efficiency increased from 62.3% to 95.5% with increasing concentration of extracts from 200mg/l to 1000mg/l. Activation energy increased from 36.019 KJ/Mol to 59.628KJ/Mol as inhibitor concentration increased from 0.45 to 1.20g/L indicating the difficulty of corrosion to take place and also free energy reduced from-18.689 KJ/Mol to-26.592KJ/Mol for the same concentration of the inhibitor. The electrochemical impedance study gave a convincing proof, that corrosion inhibition of aluminum in acid medium takes place through adsorption process that occurs on the surface. Polarization curve measurements really indicate that the studied extract showed to be a mixed type inhibitor. The increasing value of constant phase elementl exponent, that is, the phase shift (n) with increasing inhibitor concentration indicated that surface roughness decreased with increasing inhibitor concentration which is also seen in the scanning electron microscopy. The adsorption of DT extracts in acid aenvironment on aluminum obey Langmuir adsorption isotherm since it is the isotherm that gave the best fit for the experimental data. SEM confirms the existence of film coating layer on the metal solution interface. It was observed that bio-sourced plant extract, Dennattia Tripatalla (DT) is very effective as green corrosion inhibitor for aluminum in acidic medium

Lecture Notes in Civil Engineering, 2020

Conventional road drainage system commonly adopted in the city of New Owerri Nigeria is grossly i... more Conventional road drainage system commonly adopted in the city of New Owerri Nigeria is grossly ineffective and unsustainable, and this gives rise to prolonged pools of water after cessation of rainfall. The water pools often cause road pavement failure, disruption of free flow of traffic, submergence of residential apartments, disruption of commercial activities and exponential rise in mosquito population due to the occurrence of fertile breeding grounds. Research has shown that the use of a trenchless drainage system in road construction, whereby an engineered open trench is backfilled with relatively permeable material, can be a suitable alternative on the flat terrain. It was observed that a 50 cm depth of water completely drains off in such a system within 30 min of cessation of rainfall, instead of the usual two to three weeks duration. Five conditions were examined in the course of the research. The rate of drawdown recorded for the various conditions are 3.7 cm/min for open trench i.e. without a backfill; 3.3 cm/min for trench backfilled with gravelly sand; 2.8 cm/min with fine sand; 2.0 cm/min with mixed sand and 3.5 × 10−4 cm/min for the open concrete drain. It was observed that materials with higher values of both the diameter at 30% passing and coefficient of uniformity are more effective in the drain ability. The unit construction cost of standard concrete drain was found to be about two (2) to three (3) times higher than that of an equivalent sized trenchless drain filled with gravel.

EngRN: Process Engineering (Topic), 2019

In queueing problems in an industry, performance characteristics are the major indicator of the o... more In queueing problems in an industry, performance characteristics are the major indicator of the operation performance. This paper presents the performance characteristics response of palm kernel oil plants to increasing number of processing machines, in Imo state. Five plants producing vegetable oil using palm kernel, in Imo state, with average installed capacity of 70 Tonnes were sampled for analysis, using queue methodology. Engagement of less than 4 processing machines per day resulted in exploded queue. Increment from 4 – 7 processing machines per day reduces the queue length and mass in the system by 99.7% and 92% respectively. Also, at the installation of 7 processing machines, the waiting time in queue and queue length were 0.07 days and 1.59Tonnes/day respectively. In addition, at 5 numbers of machines operating, there was virtually no queue in the system. In general, as the number of processing machines increased beyond 3 numbers, performance characteristics decrease.