The possibility of the electrochemical execution of hydrogen peroxide sensing on CoSn(OH)6 has been evaluated from the mechanistic theoretical point of view. The correspondent model has been developed and analyzed by means of linear stability theory and bifurcation analysis. It was shown that this material may be an excellent electrode modifier for H2O2 electrochemical detection, and the electrochemical analysis is realized in a plausible way. The electroanalytical process is diffusion-controlled. The oscillatory and the monotonic instabilities in this system are possible, being caused not only by electrochemical factors, but also by those of autocatalytic behavior during H2O2 reduction

The possibility of use of cobalt(III) oxyhydroxide as an electrode modifier in electrochemical analysis of paraquat pesticide has been evaluated from the theoretical point of view. The electrochemical function mechanism has been suggested, and the correspondent mathematical model has been analyzed by means of linear stability theory and bifurcation analysis. It was shown that the cobalt(III)oxyhydroxide may be efficient cathode modifier for paraquat electrochemical reduction in neutral media. The steady-state stability is maintained in vast parameter region. The possibility for oscillatory and monotonic instabilities has also been verified.

The middle section of River Kaduna has been known of being polluted by both point and non-point pollutant sources however, a detailed modelling of the self-purification capacity of the river has not been done. Hence, this research investigated the relationship between some selected parameters with respect to the self-purification potential of the river. This was achieved by monthly analysis of the selected parameters which include saturated oxygen deficit (), water temperature (), Oxidizable organic matter present in water (), flow velocity () and depth of flow () across eight (8) sampling sites for 24months using standard methods. Results revealed that the loss of dissolved oxygen (deoxygenation) in the water quality due to pollutants, occurred at a rate lower than the dissolved oxygen recovery (reoxygenation) as the water flow downstream irrespective of sampling site and season. Hence, the self-purification capacity of the river based on Fair’s ratio was found to be higher than unity as it ranged from 1.45 to 3.98 notwithstanding, the higher values were recorded during rainy season. Results also informed that the modelled equation is more influenced by parameters  and  compared to ,  and  in estimating the self-purification capacity of the river, and predicted values generated through the model had no significant difference with observed values, on t-test analysis at p < 0.01. Furthermore, the analysed results identified the most polluted zone within the monitored section of the river and necessary recommendations were made.

Thin film solar cells required good absorber layers to convert solar radiation to electricity. Cadmium telluride (CdTe) and copper indium gallium diesselinide (CIGS) are most popular absorber layer for thin film solar cell but toxicity of cadmium and scarcity of tellurium, indium and gallium limit the usage and availability of the films. Copper zinc tin silphide (CZTS) thin films have nontoxic and abundant elements. CZTS thin films were deposited onto soda lime glass (SLG) using chemical bath deposition method at room temperature. The precursor solution was made from copper nitrate, zinc nitrate, tin chloride and thiourea as sources of Cu, Zn, Sn and sulphur, respectively. The time of depositions were varied between 15 and 90 minutes in 15 minutes interval.  The films were characterized by UV Visible spectrophotometer, Scanning electron microscopy and energy dispersive spectroscopy (EDS) for optical, surface morphology and elemental compositional studies. The optical parameters showed that low reflectance, transmittance and high absorbance with band gap energy of 1.50 -1.62 eV.

The water quality of Gin River has deteriorated due to various severe reasons. The aim of this study was to determine the variation of water quality and to develop a mathematical model for water quality prediction. In this research, nine water quality parameters including pH, Dissolved Oxygen, Turbidity, Temperature, Biochemical Oxygen Demand, Total Phosphate, Nitrate, Total Solids, and Fecal Coliform were tested by collecting samples from January 2022 to May 2022 from six sampling locations. Afterward, Water Quality Index (WQI) was calculated using National Sanitation Foundation method. The highest value (66.24) was recorded at location 3 in January, and the lowest (55.81) was recorded at location 1 in May, whereas all samples were in medium water quality range. The results were analyzed based on location and time. A mathematical model was developed with an additional parameter: Electric Conductivity (EC).  The validation of the model was done by comparing the WQI values obtained from four previous studies and WQI values obtained from mathematical model which was calculated from raw data of selected studies. The accuracy of the model was recorded between 86% to 92%. Ultimately, this model can be used to predict the water quality of any river in Sri Lanka.

The potential inhibition effect of anisaldehyde on the aluminium corrosion in H3PO4 solution was studied through loss of weight measurement and characterization was done by FTIR and SEM analysis. The anisaldehyde shows an excellent inhibition action and served as an alternative to existing inorganic toxic inhibitors. The inhibitor concentration effect was studied at temperature range of 308 - 318 K and the result showed that inhibition efficiency increase with rise in the inhibitor concentration and retard with temperature increment. The activation energy value in blank acid solution was 32.61 kJ/mol which reached 48.22 kJ/mol with the addition of 0.1 M inhibitor concentration. The enthalpy of adsorption values were found to be positive that prove the endothermic behavior of the reaction. The entropy values were negative and that suggests an involvement of association adsorption process rather than dissociation mechanism, which also leads to ordered activation complex formation between the adsorbent and adsorbate. Gibbs free energy of adsorption (ΔGads) values were negative, thus reflect the spontaneity of the whole process. The adsorption equilibrium constant (Kads) values retards with rises in temperature as a result of the destabilization of inhibitor from the surface of aluminum. The inhibitor adsorption behavior was accurately described by Langmuir adsorption isotherm model.

The radiological hazard assessment due to the Natural Background Radiation in the Yewa South Local Government area has been carried out. Twenty (25) soil samples were collected from selected towns in Yewa South which include Idogo, Ilaro, Itolu, Iweke and Owode. The collected samples were air-dried, pulverized and homogenized before being analysed by gamma ray spectrometry. The mean activity concentration of 226Ra, 232Th and 40K in soil samples were 12.9 ± 3.38, 6.40 ± 0.37 and 91.45 ± 4.63 Bq/kg respectively for Idogo; 5.72 ± 0.33 and 70.71 ± 3.60 to 148.40 ± 7.82 Bq/kg respectively for Ilaro; 24.66 ± 2.75, 5.35 ± 1.32 and 80.97 ± 4.12 Bq/kg for Itolu; 7.91 ± 1.02, 4.42 ± 0.28 and 105.25 ± 5.36 Bqkg-1 for Iweke and 26.20 ± 3.25, 4.84 ± 0.29 and 61.68 ± 3.26 Bqkg-1 for Owode. The mean activity concentration values of 226Ra and 232Th and 40K obtained from all study sites were lower than their respective world average values of 35 and 30 Bqkg-1 and 400Bqkg-1 [12]. The average absorbed dose rates at 1m above the ground delivered to the general public of the study areas were all lower than the world average value of 58 nGyh-1. The average values of Radium Equivalent (Raeq) for all the study areas were found to be below the world average of 370Bqkg-1 and the computed mean Annual effective dose (AED) from all study sites was also found to be below the safety limit of unity. Thus, based on the results obtained from this study, no hazardous radiological effects are posed to the populace in the vicinity of the investigated locations.Keywords: Activity concentration, Gamma Ray Spectrometry, Radionuclide.

The theoretical description of the electrochemical determination of sudan dyes, assisted by novel triazolic derivatives, using a disulfonic organic acid as a binder, has been made. The correspondent mathematical model was analyzed by means of linear stability theory and bifurcation analysis. It was shown that the electroanalytical process is realized more efficiently than in the case of the direct electrochemical reduction in acid media. The oscillatory behavior for this case is possible, but less probable than for direct dye electrochemical reduction.

In this research, the compound was studied theoretically using computational methods to give further analysis on the inhibition of oleuropein on mild steel and Aluminium. Parameters were studied using quantum chemical method through DFT and molecular dynamic simulations. Mild steel Fe (111) and Al (110) surfaces was used due to their respective close packed and densely atom. Fukui function, the local and global reactivity were calculated to give the reactivity of the molecule. Based on the values of calculated adsorption and binding energies (-70.287, 70.287 Kcal/mol) and (-113.193, 113.193 Kcal/mol) obtained on both surfaces, the mechanism of oleuropein is inferred to exhibit physiosorption on Aluminium surface and Chemisorption on mild steel surface.

This study was aimed at assessing both the effect (risk) and impact of a recent oil spill on heavy metal concentration in the Santa Babara River in Bayelsa State, Nigeria. Samples were collected and preserved based on standard methods. The heavy metals of interest were Mercury (Hg), Arsenic (As), Cadmium (Cd), Chromium (Cr) and Copper (Cu) due to their levels of toxicities and presence in water bodies while the five study stations were Worokuma (W), Uwanga (W), Tuweni (T), Shellikiri (S), Inarakiri (I) and  Esenfakiri (E). The solar thermos elemental flame atomic absorption spectrometer (AAS), model SE-71096 made in Germany with detection limit of 0.001 mg·kg−1 was used for the heavy metal analysis. The trend of heavy metal abundance was found in this order Cr>Cu>Cd>Pb>Hg=As. The hazard index (HI) indicated that in all the stations, calculated values of greater than one occurred. All the detectable metals had risk index of greater than 5 but the highest was found in the order, Cd> Pb > Cu > Cr (149, 35, 26 and 12 respectively) which meant extremely high level of pollution. This also indicated the probability of non-carcinogenic effects occurring and increases as HI increases signifying carcinogenic risk via direct ingestion of water. The Incremental Lifetime Cancer Risk (ILCR) for Cadmium (Cd), Pb and Cr recorded calculated values above the maximum limits of 1.0 x 10-4 in all the stations especially for adults in station U (0.018) and children in station S(0.567) for cadmium. Regular monitoring of the Santa Barbara River is of essence as most of the inhabitants use it as the only source of potable water as their wells have very high iron content.