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Sixteen Meloidogyne isolates from tomato fields in California grown with resistant cultivars were multiplied on resistant tomato in a greenhouse. Of these resistance-breaking isolates, one was identified as M. javanica, and all others as M. incognita. The reproduction of the M. javanica isolate and four M. incognita isolates on six resistant tomato cultivars and on susceptible and resistant cultivars of pepper, sweetpotato, green bean, cotton, and cowpea was evaluated and compared to an avirulent M. incognita population in greenhouse pot trials. On resistant tomato cultivars, there were minor but significant differences between the resistance-breaking Meloidogyne isolates and between the different tomato cultivars. Of the other resistant crop cultivars, pepper was resistant to all isolates and green bean to all M. incognita isolates, while cotton and cowpea allowed reproduction of one of the resistance-breaking M. incognita isolates. The resistant sweetpotato cv. Bonita behaved like resistant tomato, allowing reproduction of all five resistance-breaking isolates but not of the avirulent M. incognita. Our results showed that variability exists among resistance-breaking Meloidogyne isolates, and that isolates overcoming resistance in tomato may also be virulent on resistant sweetpotato.

Two mathematical models, which describe the dependence of critical pitting temperatures of 06ХН28МДТ alloy (analogue of AISI904L steel) in model recycled water with pH 4-8 and chloride concentration from 350 up to 600 mg/l on chemical composition and structure, are developed. They are based on multivariate regressions with pairwise combinations of features and a three-layer neural network of direct signal. Applying the developed mathematical models, it is found that the critical pitting temperatures of the 06ХН28МДТ alloy increase with an increase in the pH of model recycled water, the content of Cr, Mo, Cu, the volume of titanium nitrides within it, and a decrease in the medium austenite-grain diameter, the content of nickel within the standard, and chlorides in the media. At the same time, the analysis of the developed mathematical model, which is based on multivariate regressions with paired combinations of features (alloy and media parameters), reveals that the content of Cr and Ni in the alloy in combination with the medium austenite-grain diameter most significantly affect its pitting resistance in model recycled waters, and an effect of the Cr content in combination with pH and chloride concentration in the media is somewhat lower, but much higher than an effect of the Mo and Cu content, and the volume of titanium nitrides in combination with the media parameters. The developed mathematical model, which is based on a three-layer neural network of direct signal propagation, is recommended for predicting the pitting resistance of heat exchangers made of 06ХН28МДТ alloy or AISI904L steel when operating in recycled water. In addition, the developed mathematical model, based on multivariate regressions with paired combinations of features (alloy and media parameters), is recommended for selecting the optimal melts of this alloy or steel, which are most resistant to pitting in recycled water. [ABSTRACT FROM AUTHOR]

The limited amount of economically suitable natural uranium resources forces us to improve the existing structure of the nuclear power system and its fuel cycle. With the current natural uranium reserves, it becomes practically impossible to significantly increase nuclear power plant (NPP) capacities in the existing system on the basis of thermal reactors operating in the open nuclear fuel cycle (ONFC). In order to solve this problem, the article considers the introduction of fusion-fission reactors (FFRs). FFR blankets produce 233U, which is further utilized in thermal reactors. In this article, fuel compositions of VVER-1200 reactors with the addition of 233U and thorium are studied, which make it possible to reduce the consumption of natural uranium and/or utilize already available raw materials in the form of depleted and regenerated uranium. On the basis of the scenario of the Russian nuclear power system (NPS) development within the ONFC with VVER-1200 reactors, the required 233U production volumes and the corresponding FFR fraction are determined for all fuel options. The risks of thorium introduction into the nuclear fuel cycle (NFC) are reviewed. [ABSTRACT FROM AUTHOR]