Advanced Materials Research Vol. 813

Abstract: The manipulation of emulsions at micrometer-scale is a challenging topic for industrial application, especially for monodisperse microemulsions production. The development of material science and afterwards the creation of polymer confinement proposed efficient devices for micrometer scale emulsions fabrication. In this work, the flow regime of emulsion generation was studied to depict numerical manipulation of micrometer-scale emulsions through biomicrofluidic technology. At first, correlation analysis between experiment conditions and results were conducted, then different linear modeling and non-linear modeling, including Artificial Neural Network Modeling (NNM) technology, were performed to characterize the emulsion variation. Both models can well manipulate emulsion variation. Compared with linear modeling, non-linear models ameliorate the performance on the manipulation of micrometer-scale emulsion.

Abstract: Chemical bath deposited ZnS thin films are promising buffer layers for thin film solar cells, replacing the environmentally hostile CdS buffer layers currently in use. Reflection, absorption and scattering are the three main light loss mechanisms in buffer layers. In this work, improved process conditions, such as magnetic stirring and air annealing, are used in the chemical bath deposition of ZnS thin films to optimize their surface morphology, which effectively reduces light scattering and increases the transmittance, resulting much better ZnS thin films.

Abstract: A cyclic polarisation method was applied to construct the E-pH diagrams of AISI 316L stainless steel in deaearted solutions containing 1000 and 2000 ppm of sodium sulphate without and with 3550 ppm of sodium chloride. Addition of chloride ions to the sulphate solutions caused a region of imperfect passivation regime to appear, and its addition to the 1000-ppm sulphate solution considerably reduced the transpassive potential. Furthermore, the addition of sulphate ions to the 3550-ppm chloride solution enlarged the passivation regime, mainly by shifting the transpassive potentioal to the noble direction. However, the imperfect passivation regime also enlarged by the positive shift of that potential and by reduction of the protection potential. This negative role of sulphate is discussed in comparison with the role of sulphate on accelerating pit growth studied by the critical-pitting-temperature technique reported in literature.

Abstract: In this study, a 1350oC-sintered 98 mol% ZnO-1 mol% Al₂O₃ (AZO, Zn:Al= 98:2) ceramic was used as a target and deposited on glass using a r.f. magnetron sputtering system at a deposition temperature of 200°C. The effects of different H₂ flow rates (H₂/(H₂+Ar)=0% ~ 9.09%, abbreviated as H₂-deposited AZO films) added during the deposition process on the crystallization, resistivity, and optical transmission spectrum of AZO films were investigated. The Burstein-Moss shift effects were measured and used to prove that the defects of AZO films decreased with increasing H₂ flow rate. For comparison, the 2% H₂-deposited AZO films were also treated by the H₂ plasma at room temperature for 60 min (plasma-treated AZO films). The effects of H₂ plasma on the properties of the H₂-deposited AZO films were also studied. The value variations in the optical band gap (E_g) of the H₂-deposited and plasma-treated AZO films were evaluated from the plots of (αhv)² = c (hν-E_g).

Abstract: Copper was recovered from waste printed circuit board using suspension electrolysis technique in this paper. The relationships between the current efficiency, copper products purity, copper products morphology and the electrolytic conditions have been studied. When copper ion concentration was 50 g/L, sulfuric acid concentration was 90 g/L and the current density was 1.0 A/dm², current efficiency of electrolysis is improved effectively. With setting the stirring device outside the anode basket, high purity of copper is obtained when the concentration of chloride ion is 30 mg/L, concentration of copper is 40g/L and the current density is 1.0 A/dm². Smooth and compact copper is obtained when the concentration of gelatin and thiourea are 5 mg/L and 3 mg/L, respectively.

Abstract: The gypsum precipitation was investigated under different conditions of temperature and supersaturation, which has significant effects on the optimization of humidification-dehumidification process. The spectrophotometer was used to measure the precipitation induction period of gypsum. The primary nucleation of calcium sulphate solution was investigated with the combination of nucleation induction period and classical nucleation theory. It was found that a power relation existed between the induction period and the operation conditions.

Abstract: The theory of Least Squares Support Vector Machines was applied to metal surfaces cleaning by atmospheric pressure plasma arc. An intelligent predictive model of the non-linear relationship between cleaning quality and process parameters was established with the k-fold cross training of sample data. An orthogonal experiment was conducted to assess the effect of processing parameters on surface quality. The experimental results and predicted values show that the atmospheric pressure plasma arc (APPA) cleaning is effective in reducing considerably the amount of lubricant. Furthermore, it is feasible to apply LS-SVM in forecasting the cleaning quality and determining processing parameters, and the mean absolute percent error e_MAPE between predictive value and experimental value of water contact angle is 6.09%. Otherwise, the e_MAPE of working current is 4.46%.

Abstract: Metal supported catalysts in hydrogen production reactor has a very broad application prospect. However, the film adhesion of active coating with the metal support is the key problem which needed to be solved urgently. In this paper, FeCrAl alloy was chosen as the metallic substrate. The effects of oxidation temperature and time on the morphology, crystal phase and element composition of the metal surface were investigated by XRD, SEM and EDAX. The results show that after pre-treatment of FeCrAl Metallic Substrate,a dense transition layer of α-Al₂O₃ formed on the surface of the metallic support. Thus the oxidized α-Al₂O₃ layer and the γ-Al₂O₃ coating could combine together better. The optimum pre-treatment condition is at 950°C for 10h in air atmosphere.

Abstract: The sodium hydroxide calcination-hydrothermal treatment was used to modify the fly ash in this paper. The mount of alkali, the ratio of solid and liquid and the temperature of calcination were respectively studied in the process of modification. The best modified condition is that the ratio of sodium hydroxide and fly ash was 0.4:1, the ratio of solid and liquid was 1:1, and the temperature of calcination was 400°C. The zeolite-like structure was generated after modification. The modified fly ash in this paper was cheap and effective, providing a theoretical basis for wastewater treatment.

Abstract: This study demonstrates a novel hybrid surface polishing process combining non-traditional electrochemical polishing (ECP) with external artificial ultrasonic vibration. ECP, typical non-contact surface polishing process, has been used to improve surface quality without leaving any mechanical scratch marks formed by previous mechanical processes, which can polish work material by electrochemical dissolution between two electrodes surfaces. In recent paper, ECP using ultrasonic vibration have demonstrated surface improvement. This study verifies improved results than conventional ECP for additional experiments to vibration electrochemical polishing (VECP) using ultrasonic vibration. The localized roughness of work material is measured by atomic force microscopy (AFM) and scanning electron microscopy (SEM) for detailed information on surface. Besides roughness, overall surface quality, material removal rate (MRR), and productivity etc. are compared with conventional ECP.