Maintaining the working profile of blast furnaces during service

This article looks at the current working profile of blast furnaces at the Krivorozhstal’ combine. The profiles were formed during a period in which the operation of the furnaces was not forced, the supply of raw materials was inconsistent, and furnace output was irregular. The results of studies show a need for closer monitoring of the cooling system and the parameters of the profile of furnaces in the period before a scheduled maintenance. Timely action needs to be taken to eliminate problems in furnace operation caused by the presence of thick slag crusts. It is shown that the variable slag-formation conditions about the furnace circumference are due mainly to factors that affect the smelting operation from below — nonuniform blast delivery and a nonuniform distribution of the blast among the tuyeres, as well as local differences in drainage and the movement of coke in the hearth. These differences depend on the location of the iron notches. It is noted that the aggressiveness of alkalis and zinc in blast-furnace shafts has increased. An efficient furnace profile can be maintained by limiting the entry of aggressive compounds into the furnace and washing its interior to remove such compounds from the circulation loop.     

Physicochemical characteristics of polyethers prepared using double metal cyanide catalysts

Branched macromolecular polyethers (PEs) based on propylene and ethylene oxides are used as an active base for composites of demulsifiers of oil emulsions. In this work, features of the polymerization of propylene oxide in the presence of double metal cyanide catalysts are studied using the example of PE based on monoethylene glycol and glycerol by varying the molecular weight in the range of 6000–150000. Polymerization is performed in a laboratory reactor at 110–120°C and a catalyst concentration of 50 to 300 ppm. The viscosity, iodine value, and molecular weight characteristics of the PE samples are determined. It is shown that PEs with molecular weights of 6000–40000 have narrow molecular weight distributions (MWDs) and low concentrations of unsaturated impurities. A further increase in the molecular weight of PEs leads to the broadening of MWDs and a polydispersity value of 2.5–3.9, due to the formation of low-molecular weight unsaturated and bifunctional PEs. The results from this work can be employed to developing a process technology for PEs using double metal cyanide catalysts.     

Pseudogradient optimization of objective function in estimation of geometric interframe image deformations

An optimization criterion is suggested for the plan of counts in a local sample used to determine the pseudogradient of the objective function of estimation quality. The use of the criterion is considered in the case when the object functions are defined as the interframe difference mean square, the covariance, and the interframe correlation coefficient. The optimization is directed at increasing the convergence rate of estimates of the parameters of geometric interframe image deformations.     

Optimization of mismatch euclidean distance in evaluating interframe deformations of geometrical images

The criterion of optimization of the local sample plan used for finding of the estimation quality target function pseudogradient is proposed. Applications of the criterion are considered for the setting the mean squared interframe difference, covariance, and interframe correlation coefficient as a target function. Optimization aims to increase the estimation of the rate of convergence of the parameters of interframe deformations of geometrical images.     

Investigations of the torsional vibrations of a shaft with disks

Investigations of the direct and inverse spectral problems of torsional vibrations of a shaft with disks were performed. The Tolle method was used to solve the direct problem. The influence of the characteristics of a shaft with loads on the frequencies of its torsional vibrations was studied using the solution of the direct problem. It was shown that an increase in the moments of inertia of disk masses leads to a decrease in vibration frequencies and that an increase in the torsional rigidity of segments of a shaft leads to an increase in the system’s vibration frequencies. Examples, tables, and plots of the corresponding dependences are presented.     

New modified-majority voter-based efficient QCA digital logic design

ABSTRACT

Quantum-dot cellular automata (QCA) is an emerging nanotechnology and a possible alternative solution to the limitation of complementary metal oxide semiconductor (CMOS) technology. One of the most attractive fields in QCA is the implementation of configurable digital systems. This article presents a novel multifunctional gate called the modified-majority voter (MMV). The proposed gate works on the explicit interaction of the cell characteristic property for the implementation of digital circuits. This prominent feature of the proposed gate reduces the maximum hardware cost and implements highly efficient QCA structures. To verify the functionality of the proposed gate, some physical proofs, truth table and computational simulation results are performed. These results assured the validity of the existence of the proposed gate. It also dissipates less energy which has been calculated under three separate tunnelling energy levels using the QCAPro tool. To prove the effectiveness of the proposed MMV gate, several optimal irreversible arithmetic circuits such as three-input XOR, half-adder and full-adder are proposed. The modular layouts are verified with the freely available QCADesigner tool version 2.0.3.