Build your own closed loop: Graph-based proof of concept in closed loop for autonomous networks

Next Generation Networks (NGNs) are expected to handle heterogeneous technologies, services, verticals and devices of increasing complexity. It is essential to fathom an innovative approach to automatically and efficiently manage NGNs to deliver an adequate end-to-end Quality of Experience (QoE) while reducing operational expenses. An Autonomous Network (AN) using a closed loop can self-monitor, self-evaluate and self-heal, making it a potential solution for managing the NGN dynamically. This study describes the major results of building a closed-loop Proof of Concept (PoC) for various AN use cases organized by the International Telecommunication Union Focus Group on Autonomous Networks (ITU FG-AN). The scope of this PoC includes the representation of closed-loop use cases in a graph format, the development of evolution/exploration mechanisms to create new closed loops based on the graph representations, and the implementation of a reference orchestrator to demonstrate the parsing and validation of the closed loops. The main conclusions and future directions are summarized here, including observations and limitations of the PoC

Quantification and analysis of slag carryover during liquid steel tapping from BOF vessel

The amount of slag carryover (SCO) during the liquid steel tapping from the basic oxygen furnace (BOF) vessel has been estimated using a thermodynamic model that ensures the matching the predicted bath silicon with that of experimentally measured silicon in ladle furnace. FactSage 6.4 has been used for thermodynamic analysis. A simple correlation has also been established to estimate SCO immediately after the tapping process using the readily available plant data. Viscosity, interfacial tension of the slag, impurities in the liquid steel, and the tapping temperature has been found to have a profound effect on the amount of SCO. The advantage of the present method of SCO estimation compared to the other methods and the industrially viable control measures for minimising SCO is discussed in light of clean steel practices. Further, industry trials have been conducted to validate the control of SCO by tuning the BOF slag properties. © 2022 Canadian Institute of Mining, Metallurgy and Petroleum

The Role of Slag Carryover on the Non-metallic Inclusion Evolution and Magnetic Behavior in Electrical Steel

In the present investigation, a set of high-temperature experimentations were carried out to improve the understanding of the influence of slag carryover (SCO) on non-metallic inclusion evolution during the production of high silicon electrical steels for functional applications. It was observed that the liquid steel treated with synthetic slag and lime resulted in the formation of CaO-based complex oxide, sulfide, and nitride inclusions in the matrix. Whereas the top slag (synthetic slag and lime) contaminated with carryover slag transforms the complex oxide inclusions to Mn free oxy-sulfide inclusions in the high Si steel. Further, the high-silicon steel evaluated for magnetic property confirms the detrimental magnetic behavior of the steel treated using the top slag with the excess amount of SCO (10 kg/t). The increase in coercivity is due to a higher fraction of sub-micron inclusions in the steel matrix. The industry implications of the present findings are highlighted in the light of the evolution of Goss texture in high silicon steel during downstream processing. The evolution of detrimental inclusions in functional grade (electrical) steels due to the presence of SCO call for stringent process control during the upstream processing of liquid steel to maintain the desired magnetic properties. © 2022, The Minerals, Metals & Materials Society and ASM International

Fabrication of functionally graded material via gas tungsten arc welding based wire feeding additive manufacturing: Mechanical and microstructural characterization

Fabrication of functionally graded materials-FGM is an emerging technique in the field of additive manufacturing-AM. FGM is used in many applications like the marine, aerospace, and automobile sectors. This study gives first-hand knowledge on the mechanical and microstructural characterization of additively manufactured FGM wall (Commercially pure titanium (CP-Ti/Ti-Grade-9) using gas tungsten arc welding-GTAW based AM. Experimental results revealed that this particularly manufactured wall has shown better properties such as tensile strength, impact energy, hardness, and microstructural characteristics when compared to wrought alloys. Scanning electron microscopy-SEM analysis indicates the ductile mode of failure that occurred in the fractured samples. This research has successfully fabricated FGM with spatially improved properties. © 2022 Elsevier B.V

Control of Slag Carryover from the BOF Vessel During Tapping: BOF Cold Model Studies

In a modern integrated steel plant, slag-free tapping during transfer of liquid steel from the BOF vessel to the ladle is prerequisite to produce ultraclean steel for high-end critical applications. The present investigation aims to examine the drain vortices during the liquid steel tapping process. The tapping experiments were conducted in a geometrical down-scaled Perspex BOF cold model, which was more akin to the industrial practice than the other geometries previously reported in the literature. The study highlights the influence of the complex BOF shape on drain vortices during the tapping process. It is observed that vorticity behavior during liquid steel tapping from the BOF vessel is different from the earlier observations reported for the teeming process. The parametric study of the tapping process and its analysis confirmed that the threshold height for drain vortices is strongly influenced by the nozzle diameter (ND) and marginally influenced by the residual inertia of the liquid. The carryover ratio (COR) for the water-oil experiments is in agreement with the values obtained in industrial practice. Yield loss tends to increase with the increase in ND. The onset of drain vortices in the presence of overlying phase (oil/slag) during the BOF tapping process could be principally controlled by the vessel design. The physical properties of the overlying phase had negligible influence on the drain vortices. The critical times for vortex and drain sink formation were predicted based on dimensional analysis coupled with the mathematical formulation for the tapping process. A strategy to control the slag carryover during the tapping process in industry is also discussed and postulated based on the understanding developed from water modeling experiments