Prediction of strength characteristics of high-entropy alloys Al-Cr-Nb-Ti-V-Zr systems

Experimental evaluations of mechanical properties and investigations microstructure are time-intensive, requiring weeks or months to produce and characterize a small number of candidate alloys. In this work, machine learning approaches were used for prediction yield strengths of high-entropy alloys Al-Cr-Nb- Ti-V-Zr system at 20, 600 and 800 C. Surrogate prediction model was built with support vector regression algorithm by a dataset including more 30 alloys Al-Cr-Nb-Ti-V-Zr system. Four model alloys were fabricated for testing the surrogate model by vacuum arc melting. After that model alloys were annealed in a quartz tube at 1200 C 10

Markers of genes for resistance to late blight, potato virus <i>Y</i> and potato cyst nematode identified in advanced interspecific potato hybrids

Background. The harmful organisms affecting potato cause great economic damage in all areas where the crop is grown. One of the most economically important pathogens is the potato late blight (agent Phytophthora infestans Mont. (de Bary)). Also, Potato Virus Y (PVY) and potato cyst nematode (PCN) of the Ro1 pathotype, the only one that occurs in the Russian Federation, cause significant yield losses. Materials and methods. Phytopathological and molecular screening was carried out on original interspecific potato hybrids obtained in 11 crossing combinations, seven of which were studied for the first time. Hybrids resulted from crosses that involved Mexican and South American potato species as sources of late blight and PVY resistance. Field observations of late blight resistance were conducted during three seasons under high infection pressure. A part of plant material was screened in laboratory tests. PCR tests employed 9 DNA markers of genes associated with resistance to Ph. infestans, PVY and PCN of Ro1 pathotype used in our previous study. Results. In field evaluation, hybrid clones mostly expressed high, and a part of them moderate late blight resistance. Of the 6 markers of the used Rpi genes, at least two were detected in most clones, while some had 3 or 4 markers. Some clones were found to have markers of PCN resistance genes and of several genes for resistance to PVY. The cytoplasm type was determined for all plant material. Conclutions. Within a small but pedigree-diverse set of interspeсific hybrids, the markers of resistance genes to all three pests were found. A part of clones obtained by using the sources of PVY and late blight resistance which we had identified, were found to contain two or more resistance genes to these pathogens. According to the results of molecular tests, the clones were found to carry several markers of late blight and PVY resistance genes. Original interspecific potato hybrids with determined late blight resistance levels, cytoplasm type and availability of markers of genes for resistance to three pests can be used in further hybridization

Dynamical symmetry breaking in the external gravitational and constant magnetic fields

We investigate the effects of the external gravitational and constant magnetic fields to the dynamical symmetrybreaking. As simple models of the dynamical symmetry breaking we consider the Nambu-Jona-Lasinio (NJL) model and the supersymmetric Nambu-Jona-Lasinio (SUSY NJL) model non-minimally interacting with the external gravitational field and minimally interacting with constant magnetic field. The explicit expressions for the scalar and spinor Green functions are found up to the linear terms on the spacetime curvature and exactly for a constant magnetic field. We obtain the effective potential of the above models from the Green functions in the magnetic field in curved spacetime. Calculating the effective potential numerically with the varying curvature and/or magnetic fields we show the effects of the external gravitational and magnetic fields to the phase structure of the theories. In particular, increase of the curvature in the spontaneously broken chiral symmetry phase due to the fixed magnetic field makes this phase to be less broken. On the same time strong magnetic field quickly induces chiral symmetry breaking even at the presence of fixed gravitational field within nonbroken phase.Comment: 23 pages, Latex, epic.sty and eepic.sty are use

Застосування тонкошарової хроматографії та кольорових реакцій в аналізі метронідазолу

Metronidazole belongs to the group of antiprotozoal medicines and is a potential object of research in various areas of analytical toxicology.Aim. To study the metronidazole behavior when developing with color reagents generally accepted and to determine Rf values of metronidazole under chromatographing conditions in the solvent systems generally accepted in forensic toxicology.Results and discussion. It has been shown that such widely used color reagents as UV-light, iodine vapor, Wagner reagent, acidified iodoplatinate solution can be used for detecting metronidazole on chromatographic plates. Metronidazole gives positive detection results with reagents used in the TLC-screening of extracts from the biological material for substances of basic, acid and neutral nature. It has been proposed to develop metronidazole with the neutral ninhydrin solution, p-dimethylaminobenzaldehyde solution and hydrochloric acid vapors, as well as acidified iodoplatinate solution after keeping the plates in formalin vapors. The chromatographic mobility of metronidazole has been studied in 17 solvents systems; the systems are used as standard mobile phases according to recommendations of the International Association of Forensic Toxicologists for TLC-screening of organic compounds of acid, neutral and basic nature, in the general TLC-screening of organic substances in the Ukrainian forensic toxicological laboratories, and some systems investigated with the purpose of choosing the optimal individual solvents systems for the metronidazole study.Experimental part. The chromatographic plates Sorbfil® PTLC-IIH-UV and Merck® TLC SILICA GEL 60 were used as thin layers. Conclusions. The behavior of metronidazole when developing on TLC-plates with two types of a substrate (plastic and glass) and with/without luminophor (or UV-indicator) with commonly used colored reagents has been studied. The Rf values of metronidazole under chromatographing conditions in the standard solvent systems used for TLC-screening of organic compounds of acid, neutral and basic nature have been determined.Метронидазол относится к группе антипротозойных лекарственных средств и является потенциальным объектом исследований в различных областях аналитической токсикологии.Цель. Исследование поведения метронидазола при проявлении общепринятыми цветными реагентами и установление значений Rf метронидазола в условиях хроматографирования в общепринятых в судебно-токсикологическом анализе системах растворителей.Результаты и их обсуждение. Показано, что для обнаружения метронидазола на хроматографических пластинах можно использовать такие широко применяемые проявители, как УФ-свет, пары йода, реактив Вагнера, подкисленный раствор йодоплатината. Метронидазол дает положительные результаты обнаружения с реактивами, использующимися в ходе ТСХ-скрининга извлечений из биологического материала на вещества основного, кислого и нейтрального характера. Предложено проявлять метронидазол нейтральным раствором нингидрина, раствором п-диметиламинобензальдегида и парами хлористоводородной кислоты, а также подкисленным раствором йодоплатината после выдерживания пластин в парах формалина. Хроматографическая подвижность метронидазола исследована в 17 системах растворителей, среди которых подвижные фазы, применяемые в качестве стандартных согласно рекомендациям Международного комитета по систематическому токсикологическому анализу Международной ассоциации судебных токсикологов для ТСХ-скрининга органических веществ кислого, нейтрального и основного характера, в общем ТСХ-скрининге органических веществ в отечественных судебно-токсикологических лабораториях, и отдельные подвижные фазы, исследованные с целью подбора оптимальных частных систем растворителей для исследования метронидазола.Экспериментальная часть. В качестве тонких слоев использовали пластины Sorbfil ПТСХ-ІІВ-УФ и Merck TLC Silica gel 60G.Выводы. Исследовано поведение метронидазола при проявлении общепринятыми хромогенными реагентами на пластинах для ТСХ с двумя типами подложки (пластик и стекло) и с УФ-индикатором и без него. Установлены значения Rf метронидазола в условиях хроматографирования в стандартных системах растворителей, используемых для ТСХ-скрининга веществ кислого, нейтрального и основного характера.Метронідазол належить до групи антипротозойних лікарських засобів і є потенційним об’єктом досліджень у різних галузях аналітичної токсикології.Мета. Дослідження поведінки метронідазолу при проявленні загальноприйнятими кольоровими реагентами та встановлення значень Rf метронідазолу за умов хроматографування в загальноприйнятих у судово-токсикологічному аналізі системах розчинників.Результати та їх обговорення. Показано, що для виявлення метронідазолу на хроматографічних пластинах можна використовувати такі широко вживані проявники, як УФ-світло, пари йоду, реактив Вагнера, підкислений розчин йодоплатинату. Метронідазол дає позитивні результати виявлення з реактивами, що використовуються в ході ТШХ-скринінгу витяжок із біологічного матеріалу на речовини лужного, кислого та нейтрального характеру. Запропоновано проявляти метронідазол нейтральним розчином нінгідрину, розчином п-диметиламінобензальдегіду та парами хлоридної кислоти, а також підкисленим розчином йодоплатинату після витримування пластин у парах формаліну. Хроматографічну рухомість метронідазолу досліджено в 17 системах розчинників, серед яких рухомі фази, що застосовуються як стандартні згідно з рекомендаціями Міжнародного комітету з систематичного токсикологічного аналізу Міжнародної асоціації судових токсикологів для ТШХ-скринінгу органічних речовин кислого, нейтрального та основного характеру, в загальному ТШХ-скринінгу органічних речовин у вітчизняних судово-токсикологічних лабораторіях, та окремі рухомі фази, досліджені з метою підбору оптимальних окремих систем розчинників для дослідження метронідазолу.Експериментальна частина. Як тонкі шари використовували пластини Sorbfil ПТСХ-ІІВ-УФ та Merck TLC Silica gel 60G. Висновки. Досліджено поведінку метронідазолу при проявленні загальноприйнятими хромогенними реагентами на пластинах для ТШХ з двома типами підложки (пластик та скло) та з УФ-індикатором і без нього. Встановлено значення Rf метронідазолу за умов хроматографування в стандартних системах розчинників, що використовуються для ТШХ-скринінгу речовин кислого, нейтрального та основного характеру

Неэмпирические расчеты минимальных энергетических путей реакций присоединения молекулы HF к молекулам ацетилена и метилацетилена.

Potential energy surfaces of gas-phased synchronous addition of HF to acetylene and methylacetylene. A non-empirical Harthree-Fock-Ruthane method (Gaussian-03, G-31++G** basis) with electronic correlation consideration in MP2 approximation (Moeller-Plesseth 2nd grade) was used. Reaction heats and activation energies were calculated. Reaction heat of HF addition to acetylene molecule is -19.5 kcal/mol, activation energy is 52.3 kcal/mol. Reaction heats of HF addition to methylacetylene according to Markovnikov's rule and against it comprise -20.7 and -16.1 kcal/mol; activation energies are 48.0 and 53.5 kcal/mol accordingly. It was established that HF addition to methylacetylene molecule with formation of 2-fluoropropene is more energetically advantageous according to Markovnikov's rule kinetically as well as thermodynamically.Исследованы поверхности потенциальной энергии газофазных реакций синхронного присоединения молекулы HF к молекулам ацетилена и метилацетилена. Использованы неэмпирический метод Хартри-Фока-Рутана, программа Gaussian-03, базис 6-31++G** с учетом электронной корреляции в приближении МП2 (Меллера-Плессета 2-го порядка). Рассчитаны теплоты и энергии активации реакций. Установлено, что как кинетически, так и термодинамически более выгодно присоединение молекулы HF к молекуле метилацетилена по правилу Марковникова с образованием 2-фторпропена

Experimental investigation of high-energy photon splitting in atomic fields

The new data analysis of the experiment, where the photon splitting in the atomic fields has been observed for the first time, is presented. This experiment was performed at the tagged photon beam of the ROKK-1M facility at the VEPP-4M collider. In the energy region of 120-450 MeV, the statistics of $1.6\cdot 10^9$ photons incident on the BGO target was collected. About 400 candidates to the photon splitting events were reconstructed. Within the attained experimental accuracy, the experimental results are consistent with the cross section calculated exactly in an atomic field. The predictions obtained in the Born approximation significantly differ from the experimental results.Comment: 11 pages, 6 figures, LaTe

SSR analysis of modern Russian potato varieties using DNA samples of nomenclatural standards

The N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) is developing new approaches to documentation of national cultivars, taking into account recommendations of the International Code of Nomenclature for Cultivated Plants in parallel with methods of genetic certification. The nomenclatural standard of a particular cultivar represented by a herbarium specimen can be used as a reference for verifying authenticity and uniformity of cultivar specimens obtained from various sources. The verification requires fast and reliable methods for cultivar genotyping. This paper presents protocols for modified methods of DNA extraction, PCR-analysis and SSR-genotyping, which allow potato cultivars identification without the use of expensive reagent kits. A set of ten chromosome-specific microsatellite markers was used to study polymorphisms in 66 modern Russian potato cultivars, as well as in 11 pre-cultivars and breeding clones, represented by nomenclatural standards and voucher specimens, respectively. This subset of 77 specimens has demonstrated a high level of polymorphism in ten studied microsatellite loci. The SSR analysis identified 73 alleles; 7.3 alleles per locus were observed on average, the number of which varied from 3 (STG0025 locus) to 11 (locus StI046). The PIC values varied from 0.544 (STG0025 locus) to 0.836 (StI046 locus). The alleles, unique for this subset, were found at six studied loci. The high level of polymorphism at the SSR loci made it possible to unambiguously identify almost every cultivar, with the exception of the expected coincidence of microsatellite profiles of two cultivars, which are somaclonal variants. Using an optimized set of eight microsatellite markers, the genetic relationships of modern Russian potato cultivars were studied

Modelling of the rolling process of titanium alloy tube billets in laboratory conditions on a RSP 14-40 rolling mill

The development of screw rolling technology for the production of hot-deformed tubes over Ø250 mm on a SVP-500 rolling mill faces a number of challenges that influence the quality of tubes, such as: the screw trace formed on the external surface of tubes and bending of tubes that makes impossible subsequent manufacturing operations. The following experimental and laboratory research was performed to solve these problems: a number of experimental tube billets with and without mandrels were rolled to various strains on a RSP 14-40 laboratory rolling mill to obtain the best ratio of wall thickness to the external diamete