The use of coconut shell particulates to enhance the insulating refractory properties of Ukpor, Osiele and Kankara fireclays in Nigeria was studied in this paper. The chemical analysis of the raw materials was conduct...The use of coconut shell particulates to enhance the insulating refractory properties of Ukpor, Osiele and Kankara fireclays in Nigeria was studied in this paper. The chemical analysis of the raw materials was conducted using Atomic Absorption spectrometer. The samples used for different tests were prepared by mixing the clay, bentonite and coconut shell, of grain sizes of 212 - 600 μm. The prepared samples were air and oven dried for 24 hours at room temperature and at 110°C respectively. The samples were then fired at different temperatures in the range of 950°C to 1200°C at 50°C interval and at 2.5°C/min. The fired samples were investigated for their physical, insulating (thermal) and mechanical properties. Micro-structural examination was also carried out. The results indicate that clays with 25 wt% - 30 wt% coconut shell and grain sizes of 212 - 300 μm fired at 1150°C - 1200°C possess enhanced mechanical, physical and insulating (thermal) properties. The SEM micrograph revealed the formation of mullite phase in the bricks fired at 1150°C. Thus, high quality refractory bricks with enhanced insulating properties could be produced from Ukpor, Osiele and Kankara fire-clays blended with coconut shell particulates.展开更多
In establishing a plant or factory, the cost-benefit analysis is needed to determine the viability for such financial investment on the project. In this paper, the cost establishing a factory of 200,000 bricks per ann...In establishing a plant or factory, the cost-benefit analysis is needed to determine the viability for such financial investment on the project. In this paper, the cost establishing a factory of 200,000 bricks per annum capacity, for the production of high quality refractory bricks from locally available raw materials in Nigeria was evaluated. The evaluation was conducted on the virgin refractory material (100%) as well as with varied percentages (10% - 40%) of alumina additions. The result of cost benefit analysis indicated that, the project was viable, with the highest cost at N1,203.66 per brick as against N1,800 (at 3 years projections) of the imported brick. The payback period for the capital investment was very short (within two years). The findings will aid investors in decision makings.展开更多
This paper studies the antimicrobial activity of selected engineering materials surfaces at room and chill temperatures. The antimicrobial effects of selected materials surfaces were evaluated by dropping the test pie...This paper studies the antimicrobial activity of selected engineering materials surfaces at room and chill temperatures. The antimicrobial effects of selected materials surfaces were evaluated by dropping the test pieces into prepared cultures of Bacillus spp, Escherichia coli, and Staphylococcus aereus isolated from fruits, animal feaces and natural environment respectively. Bacteria count obtained after 0, 30, 60, 90, 120, 180, 240 and 300 minutes at room temperature and chill condition was taken and compared with their initial count. The amount of live bacteria drops by several orders of magnitude, to zero, on metallic copper and brass within 30 to 300 minutes in both room and chill conditions. In contrast, no reduction is seen in the number of colonies of live bacteria on plastics, ceramic and stainless steel in both room and chill conditions. These results suggest that the selection of metallic copper and brass for touch surfaces in hospitals, surfaces exposed to fruit processing and household utensils can materially assist in reducing bacterial contamination, which should lead to a reduction in the transmission of infectious organisms.展开更多
文摘The use of coconut shell particulates to enhance the insulating refractory properties of Ukpor, Osiele and Kankara fireclays in Nigeria was studied in this paper. The chemical analysis of the raw materials was conducted using Atomic Absorption spectrometer. The samples used for different tests were prepared by mixing the clay, bentonite and coconut shell, of grain sizes of 212 - 600 μm. The prepared samples were air and oven dried for 24 hours at room temperature and at 110°C respectively. The samples were then fired at different temperatures in the range of 950°C to 1200°C at 50°C interval and at 2.5°C/min. The fired samples were investigated for their physical, insulating (thermal) and mechanical properties. Micro-structural examination was also carried out. The results indicate that clays with 25 wt% - 30 wt% coconut shell and grain sizes of 212 - 300 μm fired at 1150°C - 1200°C possess enhanced mechanical, physical and insulating (thermal) properties. The SEM micrograph revealed the formation of mullite phase in the bricks fired at 1150°C. Thus, high quality refractory bricks with enhanced insulating properties could be produced from Ukpor, Osiele and Kankara fire-clays blended with coconut shell particulates.
文摘In establishing a plant or factory, the cost-benefit analysis is needed to determine the viability for such financial investment on the project. In this paper, the cost establishing a factory of 200,000 bricks per annum capacity, for the production of high quality refractory bricks from locally available raw materials in Nigeria was evaluated. The evaluation was conducted on the virgin refractory material (100%) as well as with varied percentages (10% - 40%) of alumina additions. The result of cost benefit analysis indicated that, the project was viable, with the highest cost at N1,203.66 per brick as against N1,800 (at 3 years projections) of the imported brick. The payback period for the capital investment was very short (within two years). The findings will aid investors in decision makings.
文摘This paper studies the antimicrobial activity of selected engineering materials surfaces at room and chill temperatures. The antimicrobial effects of selected materials surfaces were evaluated by dropping the test pieces into prepared cultures of Bacillus spp, Escherichia coli, and Staphylococcus aereus isolated from fruits, animal feaces and natural environment respectively. Bacteria count obtained after 0, 30, 60, 90, 120, 180, 240 and 300 minutes at room temperature and chill condition was taken and compared with their initial count. The amount of live bacteria drops by several orders of magnitude, to zero, on metallic copper and brass within 30 to 300 minutes in both room and chill conditions. In contrast, no reduction is seen in the number of colonies of live bacteria on plastics, ceramic and stainless steel in both room and chill conditions. These results suggest that the selection of metallic copper and brass for touch surfaces in hospitals, surfaces exposed to fruit processing and household utensils can materially assist in reducing bacterial contamination, which should lead to a reduction in the transmission of infectious organisms.
