Browsing by Author "Nkwocha, A. C."

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    Environmental assessment of vehicular emission in Port-Harcourt City, Nigeria
    (U. P., 2017) Nkwocha, A. C.; Ekeke, I. C.; Kamalu, C. I. O.; Kamen, F. L.; Uzondu, F. N.; Dadet, W. P.; Olele, P. C
    Port Harcourt is a coastal city located in the Niger Delta region of Nigeria, with very short dry season and long heavy rainy season periods. The objective of this study was to assess air pollution level from vehicular emission during the rainy season period. Three locations in the city noted for high traffic congestion were selected for the study. Air sampling in these locations were carried out for 11 days, covering peak and off peak periods. The following air pollutants were measured namely; nitrogen oxides (NOx), sulphur oxides (SOx), carbon monoxide (CO) and unburnt hydrocarbons (CxHy), as well as climatic elements – ambient temperature and relative humidity. The air pollutant levels obtained were compared with local and international standards. CO complied with interthe health risk associated with ainational standard, but exceeded local standard. There is need for effective air pollution monitoring and control, this will go a long way to reduce the health risk associated with air pollution in the city..
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    Mathematical modelling of drying characteristics of pepper (Capsicum annum)
    (U. P., 2015-09-15) Nkwocha, A. C.; Kamalu, C. I. O.; Dadet, W. P.; Uzondu, F. N.; Ogbonna, O. C.
    The effects of drying condition on the drying behaviour of pepper (C. annum) and the applicability of three thin-layer drying models namely; Page, logarithmic and Flick’s law, to predict the drying behaviour of pepper were studied. The experiments were conducted in a constant temperature hot air drying oven. Three temperatures (50, 60, and 700 C) were studied. Drying air temperature was found to be the main factor affecting the drying kinetics of pepper; raising the drying temperature from 500C to 700 dramatically reduced the drying times. Higher equilibrium moisture contents were obtained at lower temperatures. Furthermore, drying was observed only in the falling rate period, and comparison among drying models was made using statistical analysis to select the best fitting model for the drying curves. Among the three tested models, Page model was found to be superior to the other models in terms of fitting performance, in fitting the experimental data, providing the highest coefficient of determination (R2) value -0.9944, and the lowest root mean square error (RMSE) value - 0.03032.
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    Studies on optimal conditions for the preservation of ‘Zobo’ drink
    (Vandana Publications, 2015-11) Ekeke, I. C.; Nkwocha, A. C.; Kamen, F. L.; Kamalu, C. I. O.; Uzondu, F. N.
    The study was carried out to determine the combination of preservation techniques (hurdles) that can best extend the shelf life of Zobo drink. Zobo drink was prepared from the calyx of Hibiscus sabdariffa. Two types of spices - Zingiber officinale (ginger) and Caryophillus oromatics (cloves) were prepared and added in the following proportions 150g: 20g; 150g:10g; 100g:20g; and 100g:10g respectively, to 400ml of zobo drink. Samples of the drink were pasteurized at two different temperatures 167 C for 5min and 72 C for 6 min. All the samples were stored at ambient temperature (30 ± 20) for 9 days. Microbial analysis was performed on the samples every 2 days. The various combinations of the spices alone could not preserve the drink beyond 2 days, but, when coupled with pasteurization, the shelf life was extended. A combination of ginger (150g) and cloves (20g) was found to be more effective, and when in conjunction with pasteurization, kept the drink in sterile condition for 3 days, and extended the shelf life to 5 days