Protection of Low-Carbon Steel from Carbon Dioxide Corrosion with Volatile Inhibitors. I. Liquid Phase

It was shown that many of the known basic inhibitors of atmospheric and hydrogen sulfide corrosion (D-4-3, N,N-diethylamino-2-methylbutan-3-one, and N,N-diethylaminoethanol) fail in CO₂-containing electrolytes. Carbon dioxide corrosion in solution can be suppressed only in the presence of more hydrophobic octylamine and its higher homolog, namely, amine A. The new highly passivating inhibitors IFKhAN-72 and IFKhAN-74 are even more effective. IFKhAN-72 is superior to amine A (the best amine-based inhibitor among those studied) in protection effect and suppresses CO₂ corrosion of steel over a wide temperature range by substantially retarding both electrode reactions. Because of its high penetrating ability, IFKhAN-72 can protect steel already covered with corrosion products. In addition, this inhibitor has a prolonged aftereffect.     

Steel Protection from Carbon Dioxide Corrosion with Volatile Inhibitors. II. Vapor Phase

It was shown that the high neutralizing properties and volatilities of some of the inhibitors studied are insufficient to protect steel under these conditions. The inhibitive effect of modified, more hydrophobic aliphatic amines in carbon dioxide under conditions of periodical wetting proved to be enhanced. New inhibitors, namely, amine A and IFKhAN-72, are effective against carbon dioxide corrosion and retain their aftereffects for a long period of time.     

On the Coadsorption of Mephenaminate and Phenylundecanoate Anions at Passive Iron

Adsorption of sodium mephenaminate (SMEP), sodium phenylundecanoate (SPU), and their mixtures by oxidized iron from a borate buffer (pH 7.4) at the constant potential E = 0.2 V was studied by ellipsometry. Like the adsorption of the previously studied SMEP, that of SPU obeys the Frumkin equation with the higher Gibbs energy of adsorption (− ΔG _A ⁰ = 33.1 kJ/mol). The Frumkin equation fails for the adsorption of an equimolar SPU + SMEP mixture (inhibitor IFKhAN-31), which is described by the Bockris equation. The calculations showed that −Δ G _A ⁰ = 41.7 ± 0.2 kJ/mol and the number of water molecules displaced by an adsorbed inhibitor species from the metal-solution interface is n = 4. It was found that SMEP anions preadsorbed at oxidized iron do not affect the shape of the SPU adsorption isotherm, yet altering its constants. In the case of preadsorbed SPU, the SMEP adsorption isotherm changes its shape and cannot be described by any known adsorption equation. In addition, SMEP begins to adsorb at the electrode in lower concentrations; i.e., PU anions stimulate the adsorption of SMEP. __________ Translated from Zashchita Metallov, Vol. 41, No. 6, 2005, pp. 573–578. Original Russian Text Copyright ? 2005 by Kuznetsov, Andreeva.     

Electrodeposition of Copper-Containing Polymer Coatings from Sulfate Electrolytes Containing N-Methylpyrrolidone

In sulfate electrolytes for copper plating, N-methylpyrrolidone (MP) was found to form stable 2 : 1 complexes with the metal. The nature of electroactive species at the copper cathode depends on the MP concentration. In a concentration range from 10⁻⁴ to 10⁻² mol/l, the electrode reaction involves complexes of discharging metal ions with adsorbed MP molecules, the complexes being formed in the surface layer. At higher MP concentrations, a slow chemical step associated with dissociation of complex species in the bulk of the solution precedes ion discharge. The inhibitive effect of MP on copper electrodeposition is due to adsorbed MP molecules at the electrode; the adsorption value determines the efficiency of the additive and the wear resistance of the coating. __________ Translated from Zashchita Metallov, Vol. 41, No. 5, 2005, pp. 463–466. Original Russian Text Copyright ? 2005 by Kuznetsov, Skibina, Kuznetsova, Loskutnikova, Sokolenko.     

Alloying of Fe−Co−Ni−Al−Cu system alloys with hafnium and zirconium

Conclusions Alloying of Fe–Co–Ni–Al–Cu-base magnetically hard alloys with hafnium broadens the area of existence of the bcc solid solution. The oxidation resistance of the alloys increases and the temperature of the start of intense oxidation increases from 400 to 900°C.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 51–53, April, 1987.     

Test complex for the onboard navigation system of an airport ground vehicle

An experimental model of the onboard integrated navigation system for airport ground vehicles designed for use as part of an advanced surface movement guidance and control system is considered. The technique and the results of field tests of the system are presented. The composition and design of the mobile test stand are described.     

Modeling of Conflicting Traffic Flows

A model of a network with conflicting input traffic flows is proposed. A Monte Carlo algorithm is formulated to evaluate the number of customers in queues by every light signal in real time. An algorithm is proposed that makes it possible to identify the traffic light mode (if exists) ensuring the stability of the network. A numerical example is considered.     

Markov model of a digital stochastic generator

A stochastic process generator based on a chain of modulo-two adders with asynchronous feedback loops is investigated. The generator dynamics is described by the Erlang equations. A mathematical model of the generated stochastic process is proposed. The implementation of the generator using modern electronic devices is considered.     

Agent-based time delay margin in consensus of multi-agent systems by an event-triggered control method: Concept and computation

This paper deals with defining the concept of agent-based time delay margin and computing its value in multi-agent systems controlled by event-triggered based controllers. The agent-based time delay margin specifying the time delay tolerance of each agent for ensuring consensus in event-triggered controlled multi-agent systems can be considered as complementary for the concept of (network) time delay margin, which has been previously introduced in some literature. In this paper, an event-triggered control method for achieving consensus in multi-agent systems with time delay is considered. It is shown that the Zeno behavior is excluded by applying this method. Then, in a multi-agent system controlled by the considered event-triggered method, the concept of agent-based time delay margin in the presence of a fixed network delay is defined. Moreover, an algorithm for computing the value of the time delay margin for each agent is proposed. Numerical simulation results are also provided to verify the obtained theoretical results.