Oxygen-lance tips with a one-piece nozzle unit

Numerical simulation is used for critical analysis of existing designs to improve the cooling of oxygen-lance heads with a one-piece nozzle unit. The design and operation of the cooling system is optimized. The temperature field is calculated, and the thermal operation of the proposed oxygen-lance tips is considered.     

Membranes based on polyimide–polyaniline nanocomposites for pervaporation of organic mixtures

Polyimide–polyaniline nanocomposites were obtained by mixing poly{[4,4′‐bis(4″‐N‐phenoxy)diphenylsulfone]imide‐1,3‐bis(3,4‐dicarboxyphenoxy)benzene} (PI) and polyaniline (PANI) solutions in N‐methylpyrrolidone. These solutions were used for the preparation of homogeneous and composite membranes. Uniform distribution of PANI particles in the membranes, resulted from interactions between macromolecules, was confirmed by transmission electron microscopy. Membranes based on PI and PI–PANI were tested in pervaporation of binary organic mixtures: methanol/toluene and methanol/cyclohexane and showed a remarkable selectivity with respect to methanol. In both pervaporation processes, selectivity was improved in PANI‐containing membranes. Interactions between membrane polymers and liquid penetrants (methanol, toluene, and cyclohexane) were studied by measurements of surface tension, sorption, and pervaporation parameters. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Comparative analysis of the performance of selective and group repeat transmission modes in a transport protocol

We propose a model of a virtual connection controlled by a transport protocol in the selective and group failure modes as a Markov chain with discrete time that accounts for the influence of protocol parameters of window size and timeout duration for waiting for acknowledgements, probabilities of distorting segments in individual links of the data transmission path on the throughput of a transport connection. We have analyzed how the throughput of the control procedure depends on protocol parameters, level of errors in communication channels, and round-trip delay. We have proposed a method for choosing protocol parameters.     

Investigation of the Influence of the Technology of Blast-Furnace Smelting with the Use of Pulverized Coal Fuel and Natural Gas on the Performance Indicators of Blast Furnaces

Metallurgist - We analyze the effect of application of pulverized coal fuel (PCF) and natural gas on the parameters of blast-furnace smelting by an example of operation of blast furnaces in Ukraine...     

Capacity of the Random Multiple Access Method

A synchronous conflict model for a group of K>1 stations is designed and used in evaluating the stability of the capacity of the random multiple access method with increasing number of stations and the station individual speed.