The high temperature oxidation of Cu-32.02% Zn-2.30%Pb brass was carried in N 2 -5wt.% O 2 and N 2 -12 wt.% O 2 atmospheres. The amounts of oxygen in the oxidizing atmospheres and the time of the oxidation affected the oxide morphologies and kinetics of the oxide growth. In the first hour of the oxidation at 650 °C, oxide nanowires were noted. The average diameter, length and distance between the observed nanowires were 27 ± 0.01 nm, 0.20 ± 0.04 µm and 0.20 ± 0.04 µm respectively for the samples oxidized in N 2 -5wt.% O 2 atmosphere and 102 ± 23 nm, 0.36 ± 0.24 μm and 0.24 ± 0.08 μm respectively for the samples oxidized in N 2 -12wt.% O 2 atmosphere. The EDX and XRD analyses of the nanowires and the oxide granules confirmed ZnO nanowires and a continuous oxide layer of ZnO. The x-ray diffraction confirmed minor presence of PbO. The oxide growth kinetics followed the linear oxide growth model, for the alloy samples that were thermally oxidized in N 2 -5 wt.% O 2 atmposphere and parabolic growth model for those thermally oxidized in N 2 -12 wt.% O 2 atmospheres respectively. The values of 6.8 µm/hour and 23.03 µm/(hour) 1/2 were determined for growth constant (k), based on the two models respectively.
The study entails determination of Total Hydrocarbon Content (THC) and Total Petroleum Hydrocarbon (TPH) in borehole water of Eket Local Government Area, Akwa Ibom State, Nigeria. This was assessed using standard analytical methods. The samples were collected in triplicate from the study area with a control station. The areas were Ikot Ibiok and Atabong in Eket L.G.A while the control station was at Aka in Uyo L.G.A. The samples were extracted with hexane using liquid-liquid extraction method followed by subsequent clean-up using column chromatography. The determination of TPH was with the aid of gas chromatography fitted with flame ionization detector (GC-FID) while The THC was determined using U-V Spectroscopy. The results showed the variations of total petroleum hydrocarbon (TPH) from 784.395 ± 0.07 to 1120.500 ± 0.05 mg/L. While THC ranges from 938.21 ± 0.08 to 1,583.294± 0.02 mg/L. The average amount of TPH and THC in the water samples collected from all the sampling stations were generally higher than both the DPR limit (50 mg/L) and federal ministry of Environment (FMEnv.) acceptable standard of Petroleum Hydrocarbons in water. This indicates a serious impact of oil industrial activities on the area. Hence, our findings have indicated evidence that the borehole water samples from the study area in Eket L.G.A is under a pollution threat and underscore the need for early remediation if adverse health defects are to be prevented.
Six grades of biopolymers formulated to have oil content of 40% (M 1), 50% (M 2), and 60% (M 3) melon seed oil (MESO) and 40% (C 1), 50% (C 2), and 60% (C 3) cottonseed oil (COSO) respectively, were prepared with phthalic anhydride, and glycerol using alcoholysis-polycondensation process. The extend of polycondensation was monitored by determining the acid value of aliquots of the reaction mixture at various intervals of time. Molecular weight averages and polydispersity index (PDI) of the finished alkyds were determined by Rast method and end-group analysis. Molecular weight averages and PDI vary with differences in oil length of the alkyds, with samples M2 and C 2 respectively exhibiting the highest PDI. Molecular weight average obtained from end-group analysis and those determined by Rast method in brackets are 1338.92 (597.00), 982.33 (696.25), 1316.09 (754.03), and 1160.57 (448.13), 765.96 (583.57), 1049.92 (696.25) for samples M 1 , M 2 , M 3 and C 1 , C 2 , C 3 respectively. Number molecular weight averages calculated from end-group analysis are larger than those obtained by Rast method for both MESO and COSO alkyds and seem to grossly overestimate their molecular weights. The mode of variation of these properties indicates that the synthesis of MESO and COSO alkyds are complex. Correlation of PDI with the quality of the finished alkyds shows that the higher the PDI value the better the quality of the alkyd. Performance properties such as rate of drying, film hardness and resistance to chemicals were optimum at 50% oil length for both triglyceride oil alkyds.
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