Synthesis of manganese oxide/carbon nanotube nanocomposites using wet chemical method

Novel material with peculiar properties can be obtained by introducing foreign materials into the inner cavity of carbon nanotubes. It has been suggested that the materials encapsulated into the hollow regions of carbon nanotubes could result in a significant change of the properties of these small particles, forming new hybrid composites with extraordinary properties. In this short communication, filling of carbon nanotubes with manganese oxide by wet chemical method is demonstrated. Transmission electron microscopy (TEM) result showed the hollow structure of carbon nanotubes were filled with manganese oxide. Energy dispersive X-rays (EDX) spectra elucidate the presence of manganese oxide in the filled carbon nanotubes whereas SEM result showed that manganese oxide is not crystallized at the outer surface of carbon nanotubes.     

SIMULATED ANNEALING TO ESTIMATE THE OPTIMAL CUTTING CONDITIONS FOR MINIMIZING SURFACE ROUGHNESS IN END MILLING Ti-6Al-4V

This study presents the estimation of the optimal effect of the radial rake angle of the tool, combined with cutting speed and feed in influencing the surface roughness result. Studies on optimization of cutting conditions for surface roughness in end milling involving radial rake angle are still lacking. Therefore, considering the radial rake angle, this study applied simulated annealing in determining the solution of the cutting conditions to obtain the minimum surface roughness when end milling Ti-6Al-4V. Considering a set of experimental machining data, the regression model is developed. The best regression model was considered to formulate the fitness function of the simulated annealing. It was recommended that the cutting conditions should be set at highest cutting speed, lowest feed and highest radial rake angle in order to achieve the minimum surface roughness of 0.1385 µm. Subsequently, it was found that by using simulated annealing, the minimum surface roughness was much lower than the experimental sample data, regression modelling and response surface methodology technique by about 27%, 26% and 50%, respectively.     

Physical and adsorptive characterizations of immobilized polyaniline for the removal of methyl orange dye

Synthesized polyaniline (PANI) powder mixed with ENR-PVC polymer blend adhesive was immobilized on glass plates for the adsorption of methyl orange (MO) dye. The immobilized PANI composite was made up of plasticized PANI aggregates and was in a doped state. The incorporation of ENR-PVC blend in PANI slightly reduced the surface area from 9.2 to 8.5 m² g^-1, and its presence was confirmed through FTIR. The adsorption process was highly dependent on the aeration rate, and the pH of MO solution in which 40 mL min^-1 and ambient pH (6.5) was selected as the working conditions. The process of MO uptake onto the immobilized PANI obeyed the pseudo-second-order kinetic model, while intra-particle diffusion was found to dominate the adsorption process. The q_m of the immobilized PANI was 77.3 mg g^-1 for MO uptake and obeyed the Freundlich isotherm model. The thermodynamic study revealed that the adsorption process of immobilized PANI was spontaneous and unfavorable at high temperature. The immobilized PANI was found to be comparable with other PANI based adsorbents in term of cost, recyclability and adsorption efficiency.     

The combination of photocatalysis process (UV/TiO2(P25) and UV/ZnO) with activated sludge culture for the degradation of sulfamethazine

The major factors affecting the removal efficiency of sulfamethazine (SMT) by photocatalysis process in the presence of TiO₂ P25 or ZnO, namely the pH, the amount of catalyst and the initial SMT concentration were examined. The obtained results showed the absence of adsorption of SMT on the catalysts and the absence of degradation of SMT by direct photolysis under UV light in the absence of catalyst. The variation of the pH solution in the range 4–9 did not cause any significant degradation of SMT. The optimal amounts of each catalyst were, respectively, 0.5 and 0.25 g/L for TiO₂ P25 and ZnO. Increasing the initial SMT concentration impacted negatively the removal efficiency, which decreased from 31% to 13% and from 100% to 27% in the presence of TiO₂ P25 and ZnO in the presence of 10 mg/L and 50 of SMT after 30-min reaction time, respectively. The obtained results showed better efficiency of ZnO than TiO₂ P25 regarding both removal efficiency and chemical oxygen demand (COD) abatement. However, removal efficiency and COD abatement were not complete, even after 7 h of photocatalysis, about 92% and 41%, respectively. The biodegradability was examined after photocatalysis performed in the following conditions: [SMT]₀ = 50 mg/L, pH = 6, T = 25°C, ω = 360 rpm and 0.5 g/L of TiO₂ P25 or 0.25 g/L of ZnO. In these conditions, the removal efficiencies were, respectively, 26% and 41% in the presence of TiO₂ P25 and 55 and 92% in the presence of ZnO after 4 and 7 h of pretreatment times, respectively. The BOD₅/COD ratio increased substantially and, respectively, from 0 to 0.25 and from 0 to 0.16 in the presence of TiO₂ P25 and ZnO after 7 h of irradiation. Even if the limit of biodegradability (0.4) was not achieved, a subsequent biological treatment was considered in the presence of TiO₂ P25, leading to 58% COD abatement after a 28-day culture.     

A novel vector-space-based lightweight privacy-preserving RFID authentication protocol for IoT environment

The Journal of Supercomputing - Internet of Things (IoT) is a novel paradigm that connects several physical devices and the cyber world over the Internet. IoT technology is growing rapidly and soon...     

A new hybrid algorithm for global optimization and slope stability evaluation

A new hybrid optimization algorithm was presented by integrating the gravitational search algorithm （GSA） with the sequential quadratic programming （SQP）, namely GSA-SQP, for solving global optimization problems and minimization of factor of safety in slope stability analysis. The new algorithm combines the global exploration ability of the GSA to converge rapidly to a near optimum solution. In addition, it uses the accurate local exploitation ability of the SQP to accelerate the search process and find an accurate solution. A set of five well-known benchmark optimization problems was used to validate the performance of the GSA-SQP as a global optimization algorithm and facilitate comparison with the classical GSA. In addition, the effectiveness of the proposed method for slope stability analysis was investigated using three ease studies of slope stability problems from the literature. The factor of safety of earth slopes was evaluated using the Morgenstern-Price method. The numerical experiments demonstrate that the hybrid algorithm converges faster to a significantly more accurate final solution for a variety of benchmark test functions and slope stability problems.     

Probabilistic Fire Simulation Assessment Using Simplified Model and Zone Modelling of a Kitchen Fire Scenario

Fire Technology - Probabilistic fire simulation has been gaining interest in performance-based design approach. Very few evaluations on modelling performance can lead to...     

Surface optimization of metal halide perovskite solar cells using ZnS nanorods

Journal of Materials Science: Materials in Electronics - The present paper reports the fabrication of solar cells using surface-optimized ZnS-Perovskite composites. Initially, ZnS nanorods (NRs)...