The development of techniques to improve the welding of super duplex steels is necessary in order to ensure that the phase balance and properties of the material are not affected during this process. Hybrid arc-laser welding is a perfect combination of the advantages of both processes, producing deeper weld beads with more balanced phases than the pulsed laser process. Here, the objective was to improve the corrosion resistance of UNS S32750 weld beads by increasing the volumetric austenite percentage in the fusion zone (FZ) with a hybrid process of GTAW (gas tungsten arc welding) and pulsed laser Nd-YAG (neodymium-doped yttrium aluminum garnet). Welds were performed in bead on plate conditions with fixed laser parameters and a varying heat input introduced through the GTAW process. Additionally, welds within a nitrogen atmosphere were performed. After base metal characterization, an analysis of the FZ and heat affected zone were performed with optical microscopy, scanning electron microscopy and critical pitting tests (CPT). The synergy between the thermal input provided by the hybrid process and austenite-promoting characteristic of nitrogen led to a balanced volumetric austenite/ferrite fraction. Consequently, the results obtained in CPT tests were better than conventional welding processes, such as laser or GTAW solely.

This paper addresses several important issues for reliable assessment of the number of voltage sags in modern distribution systems. Depending on the conditions of the network voltage sags propagate differently and affect different areas of the network. The analysis has been carried out to assess the influence of network topology on voltage sag propagation. The purpose of this paper is to analyze the influence of all types of connections transformers on the propagation of voltage sags on electrical system. The study shows that some transformer winding connections like Yd have more significant influence than any other type of winding connection. For analyzes the phenomenon, it was modeled on the ATP - alternative transient program - a standard IEEE 14-bus system and a sags generator, which is able to generate any kind of voltage sag with any variations of the magnitude and phase angle. With mathematical formulations based on balanced and unbalanced circuits theories.

The main task in this paper is to present a performance analysis of a distribution network in the presence of a synchronous generator with its speed and voltage regulators, in parallel with the distribution system, for distributed generation studies. Must be highlighted that this generator is driven by a steam turbine, and the whole system with regulators and the equivalent of the power authority system in the point of connection (PAC) are modeled in the ldquoATP - Alternative Transients Programrdquo. Technical questions studied here refer to steady-state voltage profile, voltage stability, voltage dip due to a balanced three-phase fault, load rejection, distribution line outage and the behavior of machine regulators facing the aforementioned contingencies. Results show that, in some cases, the independent power producer (IPA) can be a menace to the physical integrity of the system and in other cases can be very beneficial to the distribution system in the point of connection.

Growing agricultural demands for the global population are unlocking the path to developing innovative solutions for efficient water management. Herein, an intelligent variable rate irrigation system (fuzzy-VRI) is proposed for decision-making to achieve optimized irrigation in various delimited zones. The proposed system automatically creates irrigation maps for a center pivot irrigation system for a variable rate application of water. Primary inputs are satellite imagery on remotely sensed soil moisture (SSM), soil-adjusted vegetation index (SAVI), canopy temperature (CT), and nitrogen content (NI). The system relates these inputs to set reference values for the rotation speed controllers and individual openings of each central pivot sprinkler valve. The results showed that the system can detect and characterize the spatial variability of the crop and further, the fuzzy logic solved the uncertainties of an irrigation system and defined a control model for high-precision irrigation. The proposed approach is validated through the comparison between the recommended irrigation and actual irrigation at two field sites, and the results showed that the developed approach gives an accurate estimation of irrigation with a reduction in the volume of irrigated water of up to 27% in some cases. Future research should implement the fuzzy-VRI real-time during field trials in order to quantify its effect on irrigation use, yield, and water use efficiency. Note to Practitioners —This work is motivated by the objective of managing irrigation more efficiently. It will be a site-specific irrigation management tool and we proposed a theoretical framework that aims an artificial intelligence approach to automatically create optimal control maps for a center pivot irrigation system. At the heart of this system will be the fuzzy logic, which will define the reference values for the rotation speed controllers and the individual opening of each center pivot sprinkler valve. Currently, there is a lack of these types of systems which ends up generating an increase in demand for more intelligent, automated, and accurate systems. The proposed system will be based on decision-making -whether to apply more or less water -and will use remote sensing data, therefore, the innovative irrigation system will efficiently describe the spatial variability of the crop. The results indicate that edaphoclimatic variables, when well combined with fuzzy logic, can resolve uncertainties and nonlinearities of an irrigation system and define a control model for high precision irrigation. However, it will not always be possible to reduce water consumption, but this technology has many uses to increase farm profitability.

Variable rate irrigation (VRI) is the capacity to vary the depth of water application in a field spatially. Developing precise management zones is necessary to efficient variable rate irrigation technologies. Intelligent fuzzy inference system based on precision irrigation knowledge, i.e., a system capable of creating prescriptive maps to control the rotation speed of the central pivot. Based on the VRI-prescribed map created by the intelligent system of decision-making, the pivot can increase or decrease its speed, reaching the desired depth of application in a certain irrigation zone. Therefore, this strategy of speed control is more realistic compared to traditional methods. Results indicate that data from the edaphoclimatic variables, when well fitted to the fuzzy logic, can solve uncertainties and non-linearities of an irrigation system and establish a control model for high-precision irrigation. Because remote sensing provides quick measurements and easy access to crop information for large irrigation areas, images will be used as inputs. The developed fuzzy system for pivot control is original and innovative. Furthermore, the artificial intelligent systems can be applied widely in agricultural areas, so the results were favorable to the continuity of studies on precision irrigation and application of the fuzzy logic in precision agriculture.