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۱Palm kernel fruit fiber reinforced gypsum–cement based wall panels: It’s physical and mechanical characteristics
نویسنده(ها): ،
اطلاعات انتشار: Pollution، اول،شماره۲، ۲۰۱۵، سال
تعداد صفحات: ۱۰
Agricultural waste fibers have been found to be suitable as reinforcement in cement–based composites, but studies on oil palm fiber as reinforcement in gypsum–cement wall panels are scarce. A mixture of two equal weights of gypsum and cement, with water–binder ratios of 0.45 and 0.55 were prepared. In each mix a varying percentage of fiber contents of 2%, 3% and 4% by weight of the binders were added. The properties of the wall panels were determined from cast specimen sizes of 100x 100 x 40 mm for density, moisture content and water absorption; 160 x 40 x 40mm for compressive strength, and 650 x 100 x 25 mm for bending strength. The specimens were cured in water and tested at ages of 3, 7, 14, 21, and 28 days. The results of density of the wall panels were within the range of 1634–1742 kg\m3, while the moisture content range of 3.30–8.45%, and the water absorption varies from 5 to 12%. The compressive strengths were found within the range of 1.92–5.20N\mm2 and, generally, decreases with the increasing percentage of fiber contents, but increased with curing age. The bending strength falls within the range of 2.04–4.13 N\mm2that increases with curing age and slightly increased with fiber content. It is concluded that oil palm fiber reinforced gypsum–cement wall panels are suitable as wall element.

۲Analysis of Chemical and Microbial Contents of Public Swimming Pools’ Water in Akwa Ibom State, Nigeria
نویسنده(ها): ،
اطلاعات انتشار: Pollution، دوم،شماره۱، ۲۰۱۶، سال
تعداد صفحات: ۸
This study assessed the chemical and microbial contents in the water of public swimming pools in Akwa Ibom State, Nigeria. A total of 16 public pools were selected through probability sampling from the 32 pools that existed in the five urban areas of Akwa Ibom State. Water samples were collected from the sampled pools and tested in the laboratory for chemical and microbial contents. Results showed that the chemical contents of most pools in the study area were less than the values recommended for effective disinfection of the pools. Average free chlorine ranged from 0.05 mg\L to 1.15 mg\L 2 mg\L to 4 mg\L recommended, except for sites L and M that had 2.31 mg\L and 2.42 mg\L. Total bromine ranged from 1.3 mg\L to 3.2 mg\L 4 mg\L to 6 mg\L except for sites L and M with 5.4 mg\L and 4.4 mg\L, respectively. Microbial contents of most swimming pools in the study area were higher than permissible values for swimming pools. Mean heterotrophic bacteria ranged from 2.8×104 – 8.1×104 Cfu\ml >200 Cfu\ml permissible, except for pools L and M, with 1.8×102 Cfu\ml and 1.7×102 Cfu\ml, respectively. Mean fecal coliform ranged from 2.0×103 Cfu\ml to 4.4×103 Cfu\ml >10 Cfu\100 ml permissible, except for pools L and M, with 0.0 Cfu\ml. It could therefore be concluded that only one out of every eight public swimming pools in Akwa Ibom State meet the minimum requirement for both chemical and microbial contents. This simply implies that most public swimming pools in the study area are not safe for users.
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