In the wire arc additive manufacturing (WAAM) process, the geometry of single welding beads has significant effects on the stability process and the final quality and shape of manufactured parts. In this paper, the geometry of single welding beads of 308L stainless steel was predicted as functions of process parameters (i.e. welding current I, voltage U, and travel speed v) by using the response surface methodology (RSM). A set of experimental runs was carried out by using the Box-Behnken design method. The adequacy of the developed models was assessed by using an analysis of variance (ANOVA). The results indicate that the RSM allows the predictive models of bead width (BW) and bead height (BH) to be developed with a high accuracy: R2-values of BW and BH are 99.01% and 99.61%, respectively. The errors between the predicted and experimental values for the confirmatory experiments are also lower than 5% that again confirms the adequacy of the developed models. These developed models can efficiently be used to predict the desirable geometry of welding beads for the adaptive slicing principle in WAAM.

Abstract. At present time there is not information about the influence of rigidity of hardened steel parts on the parameters of flatness deviations: EFEmax, EFEa, EFEq, which are called correspondingly greatest, arithmetic average and quadratic average. To model the variable rigidity of workpieces, an arrangement with the frame structure was used. It allowed to simulate the variable compliance of parts with constant sizes in the direction of longitudinal feed of grinding machine. Searching for models of multiple dispersion analysis was carried out using the D-optimal plan of experiment. They predicted that in rough grinding all parameters of flatness deviations increase with the growth of the part rigidity. In the subsequent grinding stages, the increase of part rigidity is accompanied by the favorable decrease of the flatness deviations. The compliance of low-rigid parts in the finishing stage of grinding should be reduced using additional technological devices.

Climate change is increasingly clear and threatening to human life. One of the consequences of climate change is the increase of sea level leading to saline intrusion and serious shortage of fresh water. Today, some technologies are used to treat saline water such as Reverse Osmosis technology (RO), Multi-Effect Distillation (MED) technology, and Multi-Stage Discharge Technology (MSF), Electrodialysis (ED) and Capacitive Deionization (CDI). Among them, CDI technology is a technique for energy-saving and economical. The conductive composite electrode based on activated carbon from Tra Bac coconut shell charcoal were fabricated which were used as a electrode for CDI device. In this study, effect of adhesives and conductors on characterization and properties of the materials was investigated. The adhessive of PVDf and conductor of CNTs was chosen. With ratio of AC/CNTs = 9:1, the composite had a specific surface area of BET of about 517 m2/g and pore size of 1.71 nm.

The models of multivariate analysis of variance and models of artificial neural networks based on the D-optimal design of experiment were carried out to predict the relative contact bearing area (t fМ , %) of the parts from titanium alloy VT22 during grinding. Parameter t fМ of part surface, measured using digital technologies, was sensitive to the variation of the technological parameters of the grinding mode. As a result of the analysis, the decrease of technological parameters is not always accompanied by the increase of the predicted value of the relative contact bearing area. In this case, with the aim of increasing the process productivity and the relative contact bearing area of ground surfaces, the parts from titanium alloy VT22 are recommended to grind by the following modes: for rough stages l = 5-12 m/min, s cr = 9-10 mm/double stroke, t = 0.02 mm, z = 0.3 mm; and for finishing stages l = 18 m/min, s cr = 4 mm/double stroke, t = 0.006 mm, z = 0.1 mm.

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