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The Zn-Ni-Mn/Zn Ni multi-layer coatings were electrodeposited under switching potential regime from an alkaline solution. In order to deposit Zn Ni layers, more positive potential −1560 mV was used as first electrodeposition potential in each cycle. More negative potentials −1860 mV and −1980 mV was used as the second potential in the various potential regime. The pulse-electrodeposited samples showed a smoother surface compared to coatings electrodeposited at a constant potential. Also, potentiodynamic polarization and electrochemical impedance spectroscopy were used to study the corrosion resistance of these coatings. All coatings electrodeposited at constant potential showed passivation behavior, while such behavior was only seen in pulse-electrodeposited samples from bathes with Mn2+ concentration higher than 1.17 μM. Samples electrodeposited using −1860 mV as the second potential for 30 s in each cycle had more positive corrosion potential and lower corrosion current density compared to samples deposited at a constant potential, while samples electrodeposited under potential regimes with more negative second potential had more negative corrosion potential and higher corrosion current density. The electrochemical impedance curves showed that the coatings electrodeposited at constant potential had higher polarization resistance and the passive layer formed at their surface was more compact than the pulse-electrodeposited ones.

The potentiostatic electrodeposition of Zn−Ni−Mn was carried out in an alkaline solution with the addition of Mn salt. The effects of electrolyte Mn2+ concentration and deposition potential on the surface morphology, phase structure and corrosion behavior of coatings were studied. The results of corrosion polarization showed that the presence of higher Mn content in Zn−Ni−Mn coatings could lead to the formation of a good passive layer with a 7-fold increase in Rp of coating and a significant decrease in the corrosion current density compared to those of Zn−Ni coating. The XRD and the XPS analyses from the surface of Zn−Ni−Mn after corrosion test showed that the passive layer was composed of zinc hydroxide chloride, zinc oxide, zinc hydroxide carbonate, and manganese oxides.

This study tries to improve methods of delineating functional urban regions (FURs) through a combination of two quantitative and qualitative methods, which are enhanced techniques: gravity analysis and flow analysis. This approach improves the gravity model by incorporating a centrality index into the model as a calibrating coefficient. Network analysis (origin–destination matrix) and spatial analysis (inverse distance-weighted interpolation) are also applied to the model within a geographic information system (GIS) environment in order to improve preciseness of distance parameter calculation. Inverse distance-weighted (IDW) interpolation helps the model improve calculation of attraction potential coefficient for the region under study (Shiraz Metropolitan Region). In addition, the census data permits flow analysis to be employed as a complementary method to adjust and revise the FUR boundary, which was initially delineated by the gravity model. The census bureau (Iran Statistical Center) provides...