The research showed the statistical analysis of clad bead width on mild steel metal geometry. The statistical analysis was performed using response surface method of statistics. The analysis of variance (ANOVA) shows that the Model F-value of 8.95 which implies that the model is significant. There is only a 0.23% chance that an F-value this large could occur due to noise. Probability values of less than 0.0500 indicate model terms are significant. The lack of fit for F-value of 1.05 implies the lack of fit is not significant relative to the pure error. There is a 51.67% chance that a Lack of Fit for F-value this large could occur due to noise. Non-significant lack of fit is good and makes the model more fit. The coefficient of determination of the parameters (R-squared) is 0.9249. The predicted R-Squared of 0.9249 is close to the adjusted R-Squared of 0.8215; however, the difference is not more than 0.2 which is of reasonable agreement. Adequate Precision measures the signal to noise ratio of 10.757, which indicates an adequate signal in the data. The fraction of design space plot, perturbation plot, normal probability plot and the cook’s distance plot show less residuals and more fitness of the data which is good in making the parameters very efficient and more effective in modeling the process. The research achieved reasonable and appropriate statistical results which portray the parameters in the system. Finally, the results are recommended for understanding the influence of the parameters in clad height of reinforcement on mild steel cladding weld metals geometry.
A high surface area mesoporous Cu2O embedded on TiO2 (Cu2O-TiO2) aerogel was prepared and used in photocatalytic splitting of water under simulated solar light irradiation. Highly efficient hydrogen production was achieved over 3 wt% Cu2O-modified TiO2 aerogel photocatalyst with a high rate of 1.40 mmol/(g·h) under simulated solar irradiation. The hydrogen production efficiency of 3 wt% Cu2O-modified TiO2 aerogel was about 33 and 9 times higher than those of pure TiO2 aerogels (0.043 mmol/g·h) and Cu2O-modified commercial TiO2, Degussa P25 (0.15 mmol/g·h) with the same ratio, respectively. For comparison, no hydrogen was detected when Cu2O was used alone as the catalyst, and the activity of Cu2O mechanically mixed TiO2 aerogel with the same ratio was 13 times lower than Cu2O-TiO2 aerogel. This result implied that the Cu2O loading was benefit to promote the separation and migration of electron-hole pair. Furthermore, the Cu2O loading enhanced the absorbance in 300-800 nm region as compared to pure TiO2 aerogel. Cu2O-TiO2 aerogels have very high specific surface area (400-500 m2/g) and good recyclability for at least 3 cycles, which suggests that the materials have promising prospects in photocatalytic hydrogen production.
Ado-Ekiti is known for abundance of moulding sands used for building, construction and foundry works. The effects of moulding sands on some metal castings was studied in this work. Four sand samples were taken from four river locations (Oke-Ureje, Omisanjanna, Odo-Ayo, and Ogbese) at Ado-Ekiti. These samples were employed as moulding material to construct moulds for the production of aluminum alloy castings. The materials were characterized and investigated to determine the effects they would have on the mechanical properties and microstructures of the castings. Even though the samples produced close value results, they all within the range of standard values for foundry operations. Oke-Ureje sand gives the highest values of yield strength, ultimate strength and Young Modulus of 105.74 N/mm2, 125.26 N/mm2 and 352.47 N/mm2 respectively.
The work index of Faya clay in Faya Village, Plateau State, Nigeria was determined for effective communition design using Berry and Bruce method. Samples of Faya clay were collected from three veins on the mine. The samples were homogenized, crushed and ground and further sampled using conning and quartering to obtain 5.0 kg representative fraction of the ore. 1.0 kg was used for composition study while 4.0 kg for experimental work. Azara barite from Nassarawa state, with work index 6.24 kwh/ton was used as the reference sample. The test and reference samples were subjected to sieve size analysis under the same condition to obtain 80% passing for both the mill feeds and products. The chemical analysis of test and reference samples shows that they both contain; SiO2, K2O, CaO, Fe2O3, TiO2 and BaO as major oxides. This is an indication that Azara barite is a suitable reference sample for Faya clay. The mineral composition of Faya clay was determined by the use of the X-ray diffraction (XRD) analysis. The major mineral phases in the clay sample are 61.7% wt. quartz (SiO2) 28.59% wt. dickite (Al2 Si2O5 (OH)). 8.89% wt. geothite (FeO (OH)4) and 0.83% wt. muscovite (K0.92 Na0.08) (Al1.86 Fe0.07 Ti0.02) (Si3.03 Al0.97) 010(OH)2, at 2θ. The SEM/EDS revealed that the dominant elements in the clay are oxygen with average weight composition of 43.75% wt. at 60 µm and 45.78 % wt. at 6 µm and silicon with 21.24% wt. at 60 µm and 27.58% wt. at 6 µm. The result of the particle size analyses of the mill feeds and products of milling indicated that 80% passing and retained as obtained from the semi-log plots were 180 µm and 125 µm for the test sample, and 250 µm and 180 µm for the reference sample. The results were validated by calculation using the Guadin- schuhman logarithm equation (log-log plots) and were in agreement with those of the semi-log plots. The value of the work index of the test sample (Faya clay) was found to be 4.83 kwh/ton. This is in line with the SEM/EDS result, indicating that Faya clay has large grains, requiring little energy to dissociate the gangue from the mineral of interest.
Electric-arc furnace dust (EAFD) is an industrial waste, which generated through the volatilization of metals during reduced iron and melting of scrap during electric arc furnaces process. Utilization of EAFD consisting of hazardous metals such as Pb, Cd, Cr or Zn using the technology of geopolymerization that is illustrated in this paper. Mixing between EAFD waste and meta-kaolin (MK) have been processed to study the potential of geopolymers as waste stopping agents. Alkali activators, which are used in this paper are sodium hydroxide (NH), sodium silicate (NS). The assessment of optimum ratio specimen of added EAFD are done by replacement of various ratio of EAFD “0, 20 , 40, 60 & 80” % with MK. Results of compressive strength of geopolymer samples increases with EAFD up to 60% and decreases with additional increasing of dust at all curing times: 7, 14, 28 & 90 days, respectively. FTIR, SEM, XRD were used to evaluate the optimization of EAFD in geopolymer formation.