Synthesis and characterisation of nanocrystalline ZrN PVD coatings on AISI 430 stainless steel

The nanocrystalline films of zirconium nitride have been synthesized using ion-plasma vacuum-arc deposition technique in combination with high-frequency discharge (RF) on AISI 430 stainless steel at 150oC. Structure examinations X-ray fluorescent analysis (XRF), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) with microanalysis (EDS), and transmission electron microscopy (TEM), nanoidentation method – were performed to study phase and chemical composition, surface morphology, microstructure and nanohardness of coatings. The developed technology provided low-temperature coatings synthesis, minimized discharge breakdown decreasing formation of macroparticles (MPs) and allowed to deposit ZrN coatings with hardness variation 26.6…31.5 GPa. It was revealed that ZrN single-phase coatings of cubic modification with finecrystalline grains of 20 nm in size were formed

Anti-corrosion ceramic coatings on the surface of Nd-Fe-B repelling magnets

The results of vacuum-arc deposition of thin ZrO₂coatings to protect the surface of Nd-Fe-B permanent magnets used as repelling devices in orthodontics are presented. The structure, phase composition and mechanical properties of zirconium dioxide films have been investigated by means of SEM, XRD, EDX, XRF and nanoindentation method. It was revealed the formation of polycrystalline ZrO₂ films of monoclinic modification with average grain size 25 nm. The influence of the ZrO₂ coating in terms of its barrier properties for corrosion in quasi-physiological 0.9 NaCl solution has been studied. Electrochemical measurements indicated good barrier properties of the coating on specimens in the physiological solution environment

On the dynamics of mortality and the ephemeral nature of mammalian megafauna

Energy flow through consumer-resource interactions is largely determined by body size. Allometric relationships govern the dynamics of populations by impacting rates of reproduction, as well as alternative sources of mortality, which have differential impacts on smaller to larger organisms. Here we derive and investigate the timescales associated with four alternative sources of mortality for terrestrial mammals: mortality from starvation, mortality associated with aging, mortality from consumption by predators, and mortality introduced by anthropogenic subsidized harvest. The incorporation of these allometric relationships into a minimal consumer-resource model illuminates central constraints that may contribute to the structure of mammalian communities. Our framework reveals that while starvation largely impacts smaller-bodied species, the allometry of senescence is expected to be more difficult to observe. In contrast, external predation and subsidized harvest have greater impacts on the populations of larger-bodied species. Moreover, the inclusion of predation mortality reveals mass thresholds for mammalian herbivores, where dynamic instabilities may limit the feasibility of megafaunal populations. We show how these thresholds vary with alternative predator-prey mass relationships, which are not well understood within terrestrial systems. Finally, we use our framework to predict the harvest pressure required to induce mass-specific extinctions, which closely align with previous estimates of anthropogenic megafaunal exploitation in both paleontological and historical contexts. Together our results underscore the tenuous nature of megafaunal populations, and how different sources of mortality may contribute to their ephemeral nature over evolutionary time.Comment: 10 pages, 5 figures, 1 table, 4 appendices, 8 supplementary figure

Expermental research of the effects of benofilin on the functional renal function in the evalution of ethylene glycol toxic loss

Effect of benofilin – a new compound among a new derivative of theophylline and hofitol (70 mg/kg) on functional renal function was studied based on the rat experimental model of acute kidney damage by ethylene glycol. The toxic products of the metabolism of ethylene glycol cause renal tubular damage resulting in acute renal failure (ARF). As a result of the application of benofilin its ability is established to prevent the death of animals in the first day of the experiment. By the ability to prevent impaired kidney function in rats benofilin exceeds the effect of the hofitol

Anomalous pressure effect on the magnetic ordering in multiferroic BiMnO3

We report the magnetic field dependent dc magnetization and the pressure-dependent (pmax ~ 16 kbar) ac susceptibilities Xp(T) on both powder and bulk multiferroic BiMnO3 samples, synthesized in different batches under high pressure. A clear ferromagnetic (FM) transition is observed at TC ~ 100 K, and increases with magnetic field. The magnetic hysteresis behavior is similar to that of a soft ferromagnet. Ac susceptibility data indicate that both the FM peak and its temperature (TC) decrease simultaneously with increasing pressure. Interestingly, above a certain pressure (9 ~ 11 kbar), another peak appears at Tp ~ 93 K, which also decreases with increasing pressure, with both these peaks persisting over some intermediate pressure range (9 ~ 13 kbar). The FM peak disappears with further application of pressure; however, the second peak survives until present pressure limit (pmax ~ 16 kbar). These features are considered to originate from the complex interplay of the magnetic and orbital structure of BiMnO3 being affected by pressure.Comment: 4 pages,4 figures, publised in Physical Review B 78, 092404/200

Reactor with Swirled Fluidized Bed Electrode for in Situ H2O2 Production and Utilization for Oxidative Treatment of Organic Pollutants

Несмотря на значительный прогресс в разработке каталитических систем окисления органических соединений в мягких условиях, их практическое использование затрудняется отсутствием дешёвых источников восстановленных форм кислорода, таких как H2O2, NaOCl и т.д. Непосредственное получение таких соединений в химическом реакторе, например, электрохимическим путём, представляется многообещающим подходом к решению этой проблемы. В данной работе предложен новый реактор для проведения окислительной обработки водных растворов, основанный на использовании закрученного псевдоожиженного электрода для электрохимического восстановления кислорода воздуха и in situ получения разбавленных растворов пероксида водорода. Реактор позволяет одновременно получать активный окислитель и использовать его для проведения окислительных реакций сразу во всём доступном реакционном объёме, что выгодно отличает его от электрохимических реакторов с плоскими электродами. В реакторе данного типа возможно применение самых разнообразных гомогенных и гетерогенных каталитических систем, использующих пероксид водородаIn spite of remarkable progress in the development of catalytic systems for oxidation at mild conditions, their application and further development are limited by the absence of cheap sources of reduced oxygen forms (H2O2, NaOCl, etc). The in situ generation of hydrogen peroxide is very promising to resolving this problem. It is suggested an approach based on in situ production of diluted hydrogen peroxide solutions from air oxygen in a new type electrochemical reactor with a swirled fluidized bed electrode for carrying out oxidative reactions with organic compounds. The reactor allows to process simultaneously the oxidant production and the oxidative reactions and to utilize entire reaction volume in contrast to electrochemical reactors with flat electrodes geometry. Reactor permits to use a variety of homogeneous and heterogeneous catalytic systems which require hydrogen peroxid

Evaluation of the effect of plant growth retardants on vegetative growth, yield components, seed quality and crop maturity of kabuli chickpea

Non-Peer Reviewe