Advances in Science and Technology Vol. 107

Abstract: Ball bearings are critical components of any industrial rotary equipment. They constitute about 90% of industrial machines’ components – and are thus responsible for the largest proportion of failures – approximately 70-85% of downtime. Defected bearings, while in service, give rise to high vibration amplitudes in rotary equipment, resulting in great reduction in their operational efficiency coupled with high energy consumption. Their premature and inadvertent failure could result in unplanned equipment downtown – thereby causing production loss and increased maintenance cost. Patently, to curtail this, it is vital that their health state is monitored throughout their service life for early faults detection, diagnosis, and prognosis. A knowledge of when a bearing will fail – that is, its remaining useful life (RUL) – can serve as supplement to maintenace decision-making such as determining in advance the time an equipment needs to be taken out-of-service and that can alternatively allow for sufficient lead time for maintenance planning as well. This can correspondingly result in enhancement in rotary systems effectiveness – i.e., availability, reliability, maintainability, and capability. Three popular condition monitoring approaches are signal processing-based approaches namely fault size estimation (FSE) and fault degradation estimation (FDE) as well as artifial intelligent (AI) based approach. It is, however, still a challenge to estimate a bearing fault size and therefore its RUL with high precision based on what has been diagnosed using these approaches. Accordingly, this review holistically explore capabilities and limitations of these approaches from recently published work. The reviewed limations are summarized and serve as new research avenue.

Abstract: Thus far, axial flow pumps remain a significant hydrodynamic unit. These pumps have common applications for various systems that require a high flow rate and a lower head. They tend to be less efficient and consume excessive power when operating at low flow conditions. Most of the studies focus on improving the hydraulic performance of these pumps based on the best efficiency point (BEP) flow conditions. This approach is mostly based on the assumption that the pump will always operate at BEP. However, this is not always the case, because the operational condition of the pump may require an adjustment to meet certain system demands. Hence, it is necessary to emphasize the need to improve the hydraulic performance of these pumps for multiple flow conditions. This means that in addition to BEP, the lowest, and the highest operational conditions need to be considered when improving the pump performance. Also, it is important to review the phenomenon of cavitation in every design optimization investigation, given its significance to pump performance and some misrepresentation which are sometimes associated with its assessment. Therefore. the main contribution of this article is to briefly discuss the successful and unsuccessful design optimization methods of an axial flow pump. Furthermore, it highlights the significance of improving the pump performance at multiple flow conditions and also to incorporate the analysis of using CFD methods to analyze the results of cavitation performance in every pump performance improvement investigation.

Abstract: Abstract Cassava (Manihot esculenta crantz) varieties: TME 419 (419), TMS 98/0581(sweet), and UMUCASS 37 (yellow) were processed into flour. Comparative studies of their physicochemical and organoleptic properties were evaluated. Proximate composition was done using the standard method of Association of Official Analytical Chemists. The sensory analysis of the cassava flour varieties was evaluated by baking bread with its wheat blends using different ratios. Results obtained showed that the moisture, crude fiber, ash content, carbohydrate content and energy value of the three cassava flour varieties differ significantly (p≤0.05); while for crude protein, the values were not significantly different (p≥0.05). Also, the swelling power, boiling point, amylose, foam capacity, and emulsification capacity of each sample was significantly (p≤0.05) different with TME 419 cassava flour having the highest values in all but foam capacity. The combination levels for bread containing wheat and cassava varieties of 75% and 25%, respectively was found to be acceptable while, bread made from 100% TME 419 cassava flour was not acceptable due to its poor sensory attributes. It was found that the carbohydrate content of TMS 98/0581 was higher than the other cassava flour samples. Breads baked with 75% wheat flour and 25% cassava flour were accepted by the sensory panel in terms of appearance, taste and texture. These results showed that high quality cassava flour has potential to replace part of the wheat flour in the production of bread since there is a wide acceptance amongst the judges.

Abstract: The research is aimed at exploring the potential of using Corchorus olitorius (Jute) seed extracts as natural coagulant for turbidity removal from water. Laboratory scale studies using jar test experiments were performed on medium turbid water to study the influence of various process parameters such as Coagulant dosage, p H, Turbidity, Colour, Hardness, Alkalinity and Bacterial count and the optimum condition for maximum Turbidity removal was identified. Results obtained showed that at 75mg/L optimal removal of turbidity was achieved. Jute seed extract was also able to maintain the p H of treated water at 7.02 with the 75mg/L dosage. However, the reduction in turbidity was below the World Health Organization (WHO) recommended value of 5NTU. The best colour removal was also not up to the WHO’s recommended value of 40TCU. The chemical analysis result showed that Jute seed powder contained 20.90% protein. When jute was used in combination with Moringa oleifera there was significant reduction in turbidity and bacterial count. At 20% jute and 80% Moringa oleifera, best colour removal, turbidity and bacterial count were obtained. Key words-Biocoagulation, Corchorus olitorius, Bacterial count, Jar test

Abstract: Heavy rainfall disasters frequently damage bridge piers due to scouring, which resulted in collapse of bridges in many areas in Japan. In this study, we developed a model for evaluating the tilting risk of bridge pier due to scouring around the pier, which fluctuates depending on rainfall conditions based on machine learning. For evaluating the risk potential of scouring, we developed a model based on past disaster data due to scouring around the pier using a neural network. Furthermore, a sensitivity analysis was conducted using the parameters of explanatory variables of the developed model, river level, and distance from the water edge to the pier. The results showed that the disaster risk around the pier due to scouring increased with the increase in river level and decrease in the distance from the water edge to the pier. Additionally, a river level prediction model was developed using support vector regression with the precipitation time measured 5 – 8 h beforehand and river level measured several hours earlier as an explanatory variable. Furthermore, this study shows that the two developed models can be combined with each other to assess the disaster risk around the jetty due to scouring, which varies with rainfall conditions, based on the observed meteorological information.

Abstract: Some organic pollutants change the color, smell, and other characteristics of water leaving it undesirable for use. However, other organic pollutants do not change the physical properties of the water, yet, they make the water non-useful. This study was carried out to determine the characteristics of petroleum contaminated water and how it can be purified using economical filters for possible reuse in rural areas of the Niger Delta, of Nigeria. The filters were made from rice husk ash, and white clay, as main materials, while calcium carbonate and poly (propylene carbonate) were used as binders and pore former. The water samples were tested for conductivity, turbidity, pH, heavy metals, and total hydrocarbon contents. The results showed a significant decrease in the amount of petroleum/organic pollutants present in the water sample before purification. The filter candle made using poly (propylene carbonate) as a binder was found to be the most efficient in removing organic pollutants, but it was not very effective in the removal of heavy metals and also, the pH of the filtrate became more acidic. Filtrates from other filters, however, had pH in an acceptable range. Dodecanoic acid and hexadecanoic acid were found to be removed from the polluted water using the filters.

Abstract: Air pollution, occasioned by the combustion of fossil fuels, is a major precursor to many health challenges. Extensive release of poisonous gaseous pollutants has continued to hamper life expectancy and wellbeing, leading to respiratory diseases, health complications and death of people that particularly live in areas which suffer high concentrations of these pollutants in the air. A proven reference to this is captured as a link to the recent Covid-19 pandemic which has claimed thousands of life since it began spreading around the global community. However, the recent global obligatory lockdown measures enforced to combat the spread of Covid-19 pandemic has shown that there was reduction in pollutant emissions released from industrial and transportation activities. This reduction was found to play a significant role in alleviating the Covid-19 complications in areas which have high levels of air pollution, which is linked to symptoms complications and high level of fatality. As a present and future remedy, the combustion of renewable biodiesel as a replacement for fossil fuels has been recognized to play a significant role in achieving increased contribution of sustainable energy as well as reducing pollutant emissions via its combustion in vehicular engines. In light of this, there is a significant need to develop quality biodiesel that can support global energy security and also ensure environmental sustainability through the reduction of pollutant emissions. More scientific methods are needed to drive biodiesel production technologies toward the development of quality fuels from novel feedstock. This study has, however, been able to highlight the connection between air pollution, Covid-19 fatality, effect of lockdown measures, and biodiesel sustainability in reduction of poisonous gaseous emissions.

Abstract: In the present work, the effect of temperature on calcium carbonate precipitation in the biomimetic calcium chloride solution was investigated. A spontaneous calcium carbonate precipitate was formed in the biomimetic calcium chloride solution as a result of the carbon dioxide hydration process. The reaction was conducted at different temperature range vary from 30°C to 100°C. The mass of the calcium carbonate precipitate and the pH solution was measured in the study. The finding indicated that an increment of the temperature has led to the fast pH reduction of the solutions to 7.0. However, the process has retarded the calcium carbonate precipitation process. The optimum temperature for higher calcium carbonate precipitation has occurred at the temperature range of 47.5°C – 65°C which gave the highest calcium carbonate precipitate at 0.121g. The addition of Tris buffer into the calcium chloride solution in this study did not gave an inhibition effect on the calcium carbonate precipitate. Based on the results, an operating condition at 47.5°C – 65°C was recommended to be used in mineral carbonization of CO₂ using the biomimetic calcium chloride solution.

Abstract: This study assessed the effect of potassium hydroxide on geotechnical properties of Biomass fuel ash stabilized lateritic soil. In-situ tests were conducted on the original soil sample for identification and classification purposes. The soil sample was classified as A-2-6. Thereafter, the soil sample was mixed with both Biomass fuel ash and Potassium hydroxide at percentages of 0, 5, 10, 15 and 0, 3, 6, 9 respectively. These were later subjected to various tests such as natural moisture content, specific gravity, sieve analysis, Atterberg limit and compaction .The result showed that the addition of Biomass fuel ash increases the Plastic limit but decreases the plasticity index of the lateritic soil. Similarly, the addition of potassium hydroxide increases the plastic limit while the plasticity index decreases.The addition of Biomass fuel ash increases the optimum moisture content while the maximum dry density decreases. Similarly, the addition of potassium hydroxide increases the optimum moisture content however the maximum dry density decreases. It could be concluded that both Biomass fuel ash and Potassium hydroxide perform satisfactorily as stabilizing agents for stabilizing lateritic soil especially for subgrade and sub base purposes in road construction