Nonlinear viscosity and velocity distribution function in a simple longitudinal flow

A compressible flow characterized by a velocity field $u_x(x,t)=ax/(1+at)$ is analyzed by means of the Boltzmann equation and the Bhatnagar-Gross-Krook kinetic model. The sign of the control parameter (the longitudinal deformation rate $a$) distinguishes between an expansion ($a>0$) and a condensation ($a<0$) phenomenon. The temperature is a decreasing function of time in the former case, while it is an increasing function in the latter. The non-Newtonian behavior of the gas is described by a dimensionless nonlinear viscosity $\eta^*(a^*)$, that depends on the dimensionless longitudinal rate $a^*$. The Chapman-Enskog expansion of $\eta^*$ in powers of $a^*$ is seen to be only asymptotic (except in the case of Maxwell molecules). The velocity distribution function is also studied. At any value of $a^*$, it exhibits an algebraic high-velocity tail that is responsible for the divergence of velocity moments. For sufficiently negative $a^*$, moments of degree four and higher may diverge, while for positive $a^*$ the divergence occurs in moments of degree equal to or larger than eight.Comment: 18 pages (Revtex), including 5 figures (eps). Analysis of the heat flux plus other minor changes added. Revised version accepted for publication in PR

Influence of cold atmospheric plasma of microdischarge on fungal mycelium and spores growing

The effect of cold plasma microdischarge on the development of spores and mycelium of fungi was investigated. The influence was investigated on Penicilium sp. The results of cold-plasma spores’ treatment showed that it could damage their outer shell and slow the colony growth, as well as stimulate germination of spores.Досліджено вплив холодної плазми мікророзряду на розвиток спор і міцелію грибів. Вплив досліджували на зразках Penicilium sp. Результати обробки спор холодною плазмою показали, що вона може пошкодити їхню зовнішню оболонку і уповільнити розростання колонії, а також стимулювати проростання спор.Исследовано влияние холодной плазмы микроразряда на развитие спор и мицелия грибов. Влияние исследовали на образцах Penicilium sp. Результаты обработки спор холодной плазмой показали, что она может повредить их внешнюю оболочку и замедлить рост колонии, а также стимулировать прорастание спор

Methane Pyrolysis over Carbon Catalysts

Methane pyrolysis at the temperature range of 550-1000 °C in gas flow reactor with fixed bed of mixed  catalysts based on carbon materials of various structure (fullerene cocoons, fullerene black, vacuum black, cathode deposit, onion-like carbon, glassy carbon, carbon fibers, mineral shungite and graphite) has been studied. Methane pyrolysis products, including stoichiometric amount of hydrogen are C3-C4 alkanes, C2-C4 alkenes, aromatics and pyrolytic carbon. Methane pyrolysis is carried out both on a catalytic surface and in a volume and contribution of the surface is determined by pyrolysis temperature. Materials with curved carbon surface show an activity in methane dehydrogenation at lower temperatures, than materials with planar basic structure elements. Materials with a small specific surface area favor methane aromatization at 950–1000 °C with formation of mainly benzene, toluene and naphthalene. The primary activation of C–H bond in methane at temperatures of lower than 850 °C, as well as the multiple dehydrogenation conversions resulting in the formation of pyrolytic carbon and its precursors (aromatics), are, probably, heterogeneous reactions

Developing European conservation and mitigation tools for pollination services: approaches of the STEP (Status and Trends of European Pollinators) project

Pollinating insects form a key component of European biodiversity, and provide a vital ecosystem service to crops and wild plants. There is growing evidence of declines in both wild and domesticated pollinators, and parallel declines in plants relying upon them. The STEP project (Status and Trends of European Pollinators, 2010-2015, www.stepproject.net) is documenting critical elements in the nature and extent of these declines, examining key functional traits associated with pollination deficits, and developing a Red List for some European pollinator groups. Together these activities are laying the groundwork for future pollinator monitoring programmes. STEP is also assessing the relative importance of potential drivers of pollinator declines, including climate change, habitat loss and fragmentation, agrochemicals, pathogens, alien species, light pollution, and their interactions. We are measuring the ecological and economic impacts of declining pollinator services and floral resources, including effects on wild plant populations, crop production and human nutrition. STEP is reviewing existing and potential mitigation options, and providing novel tests of their effectiveness across Europe. Our work is building upon existing and newly developed datasets and models, complemented by spatially-replicated campaigns of field research to fill gaps in current knowledge. Findings are being integrated into a policy-relevant framework to create evidence-based decision support tools. STEP is establishing communication links to a wide range of stakeholders across Europe and beyond, including policy makers, beekeepers, farmers, academics and the general public. Taken together, the STEP research programme aims to improve our understanding of the nature, causes, consequences and potential mitigation of declines in pollination services at local, national, continental and global scales

INSTALLATIONS FOR UNIFORM HEATING OF MASSIVE BILLETS

Статья посвящена сравнению различных установок для нагрева массивных заготовок с целью определения нагревателя, обеспечивающего наиболее равномерное распределение температуры.This article is dedicated to compare the different installations for massive billets heating to determine the heater, which provides the most uniform temperature distribution

REDUCTION OF HEAT LOSSES WITH FLUE GASES BY INCREASING THE EFFICIENCY OF USING THE SURFACE OF TG-104 WATER ECONOMIZER BOILER

Сложившаяся в настоящее время ситуация в теплоэнергетике России, выдвигает проблемы совершенствования режимов эксплуатации, существующего энергетического оборудования тепловых электростанций. В данной работе приведены результаты исследования влияния отложений на внутренних трубах водяного экономайзера на уменьшение потерь теплоты с уходящими газами.The current situation in the heat power industry of Russia, puts forward the problem of improving the operating modes, the existing power equipment of thermal power plants. This paper presents the results of the study of the influence of deposits on the internal pipes of the water economizer on the reduction of heat losses with outgoing gases

THE CALCULATOR EQUATIONS OF THERMAL CONDUCTIVITY IN THE MODEL OF A BULK LOAD OF A HIGH-TEMPERATURE FURNACE

Для имитации тепловых процессов в электропечах довольно удобно использовать метод конечных элементов в двух- и трехмерном пространстве. Теплопроводность – это свойство сплошной среды и при моделировании несплошных сред необходимо при использовании метода конечных элементов прибегать к существенному усложнению модели, что существенно увеличивает время расчетов особенно в трехмерной постановке.To simulate the thermal processes in electric furnaces it is quite convenient to use the finite element method in a two- and three-dimensional setting. The thermal conductivity is a property of the continuum and in the simulation of non-continuous environs it is necessary when using the finite element method to resort to a significant complication of the model, which significantly increases the time of the calculations especially in threedimensional statement

The marine myxosporean Sigmomyxa sphaerica (Thélohan, 1895) gen. n., comb. n. (syn. Myxidium sphaericum) from garfish (Belone belone (L.)) uses the polychaete Nereis pelagica L. as invertebrate host

Sigmomyxa sphaerica (Thélohan, 1892) gen. n. (Myxozoa, Myxosporea) with myxosporean stages in the gall bladder of Belone belone (L.) (Teleostei, Belonidae) uses the polychaete Nereis pelagica L. (Nereidae) from shallow water in the northern Øresund, Denmark, as invertebrate host. The nearly spherical tetractinomyxon-type actinospores of S. sphaerica differ from those of two species of Ellipsomyxa which also use Nereis spp. as invertebrate host. Pansporocysts of S. sphaerica were not seen. S. sphaerica is redescribed on the basis of myxospore stages from B. belone and actinospores from N. pelagica, and the phylogenetic affinities examined on the basis of ribosomal small subunit gene sequences. S. sphaerica is closest related to Ellipsomyxa spp., and is not congeneric with morphologically similar Myxidium spp. from gadids. This is the fifth elucidated two-host life cycle of a marine myxozoan

Calculating the energy spectra of magnetic molecules: application of real- and spin-space symmetries

The determination of the energy spectra of small spin systems as for instance given by magnetic molecules is a demanding numerical problem. In this work we review numerical approaches to diagonalize the Heisenberg Hamiltonian that employ symmetries; in particular we focus on the spin-rotational symmetry SU(2) in combination with point-group symmetries. With these methods one is able to block-diagonalize the Hamiltonian and thus to treat spin systems of unprecedented size. In addition it provides a spectroscopic labeling by irreducible representations that is helpful when interpreting transitions induced by Electron Paramagnetic Resonance (EPR), Nuclear Magnetic Resonance (NMR) or Inelastic Neutron Scattering (INS). It is our aim to provide the reader with detailed knowledge on how to set up such a diagonalization scheme.Comment: 29 pages, many figure