Plasma-assisted ignition and combustion

The use of a thermal equilibrium plasma for combustion control dates back more than a hundred years to the advent of internal combustion (IC) engines and spark ignition systems. The same principles are still applied today to achieve high efficiency in various applications. Recently, the potential use of nonequilibrium plasma for ignition and combustion control has garnered increasing interest due to the possibility of plasma-assisted approaches for ignition and flame stabilization. During the past decade, significant progress has been made toward understanding the mechanisms of plasma–chemistry interactions, energy redistribution and the nonequilibrium initiation of combustion. In addition, a wide variety of fuels have been examined using various types of discharge plasmas. Plasma application has been shown to provide additional combustion control, which is necessary for ultra-lean flames, high-speed flows, cold low-pressure conditions of high-altitude gas turbine engine (GTE) relight, detonation initiation in pulsed detonation engines (PDE) and distributed ignition control in homogeneous charge-compression ignition (HCCI) engines, among others. The present paper describes the current understanding of the nonequilibrium excitation of combustible mixtures by electrical discharges and plasma-assisted ignition and combustion.     

Microindentation as a perspective method for determination of mechanical properties of ribbon metallic glasses

Conditions of gauging of true microhardness of thin ribbons metallic glasses (MG) with the count of their depth are established. For the first time the method of a indentation was approved for an assessment of crack resistance of MG. The behavior of parameterKIc is found in a interval of temperature of viscous-brittle transition down to the beginning of volumetric crystallization of MG. The estimation method of temperature of viscous - brittle transition is offered at the microindentation of annealing ribbon on an elastic substrate.     

Numerical Analysis of Quasioptical Multireflector Antennas in 2-D With the Method of Discrete Singularities: E-Wave Case

Numerical method for modeling the E-polarized wave scattering by electrically large quasioptical two-dimensional (2-D) reflectors is presented. Reflectors are assumed zero-thickness and perfectly electrically conducting. Efficient numerical solution is obtained from the coupled singular integral equations discretized using new quadrature formulas of interpolation type. It has controlled accuracy and deals with small-size matrices. To simulate a small-horn feeding, the incident field is taken as a beam generated by a complex-source-point (CSP) current. Presented numerical results validate empirical rule of -10 dB edge illumination needed to provide the best electromagnetic performance of reflector     

Summarization for termination: no return!

We propose a program analysis method for proving termination of recursive programs. The analysis is based on a reduction of termination to two separate problems: reachability of recursive programs, and termination of non-recursive programs. Our reduction works through a program transformation that modifies the call sites and removes return edges. In the new, non-recursive program, a procedure call may non-deterministically enter the procedure body (which means that it will never return) or apply a summary statement.     

Engineering of functional supramacromolecular complexes of proteins (enzymes) using reversed micelles as matrix microreactors

The size of the inner water cavity of reversed micelles formedin a triple system ‘water-surfactant-organic solvent’can be widely varied by changing the degree of surfactant hydration.This gives grounds to use reversed micelles as matrix microreactorsfor the design of supramolecular complexes of proteins. Usingultracentrifugation analysis, it has been demonstrated thatthe oligomeric composition of various enzymes (ketoglutaratedehydrogenase, alkaline phosphatase, lactic dehydrogenase, glyceraldehyde-3-phosphatedehydrogenase) solubilized in reversed micelles of Aerosol OT[sodium bis(2-ethylehexyl)sulfosuccinate] in octane changesupon variation of the degree of hydration. An oligomeric complexforms under conditions when the radius of the micelle innercavity is big enough to incorporate this complex as a whole.At lower degrees of hydration the micelles ‘uncouple’such complexes to their components. The catalytic propertiesof various oligomeric complexes have been studied. Possibilitiesof using reversed micelles for the separation of subunits ofoligomeric enzymes under non-denaturating conditions have beendemonstrated. In particular, the isolated subunits of alkalinephosphatase, lactic dehydrogenase and glyceralde-hyde-3-phosphatedehydrogenase have been found to be active in Aerosol OT reversedmicelles. The dependences of the catalytic activity of oligomericenzymes represent saw-like curves. The maxima of the catalyticactivity observed at these curves relate to the functioningof various oligomeric forms of an enzyme. The radii of the micelleinner cavity under conditions when these maxima are observedcorrelate with the linear dimensions of the enzyme oligomericforms. Correlation of the position of a maximum with the shapeof an oligomeric complex is discussed.     

Ion-cyclotron resonance study of elementary stages of the catalytic oxidation of CO by N2O in the presence of VIA-group metal ions

Gas phase reactions of Mo⁺ and W⁺ ions with the molecules of various oxidants (NO, O₂, N₂O, CH₂O, C₂H₄O) were studied using ion cyclotron resonance. In oxidation with N₂O the mono-, di- and trioxide metal cations are formed consecutively. The trioxide MO₃ ⁺ ions of both metals react with CO to form CO₂ and MO₂ ⁺ ions. In this way, catalytic reaction N₂O + CO N₂ + CO₂ occurs in the gas phase with MoO₃ ⁺ /MoO₂ ⁺ and WO₃ ⁺/WO₂ ⁺ couples as catalysts. The rate constants have been measured for both stages of the catalytic cycle as well as for the stages of the catalyst preparation. Metal-oxygen bond energies were estimated for MoO_x ⁺ and WO_x ⁺ species with various x. The mechanism of CO oxidation with MoO_x ⁺ and WO_x ⁺ cations as catalysts in the gas phase is discussed in comparison with that for the oxidation over classical solid oxide catalysts.     

Life under ice in the perennial ice‐covered Lake Glubokoe in Summer (East Antarctica)

This study focuses on hydrological and biotic variables in Lake Glubokoe, which is located in Thala Hills of Enderby Land (East Antarctica). Water and sediment samples and physical measurements were collected once a week in the austral summer (19 December 2010 – 6 February 2011). This lake exhibits perennial ice cover that reached a thickness of 2.5–2.7 m during the study period. A very low concentration of planktonic chlorophyll‐a (0.06–0.45 μg L^?1) was measured in the lake, indicating its ultra‐oligotrophic status. The water was poorly populated by algae and metazoans, especially in upper waters below ice cover to a depth of 2 m. Small planktonic organisms (2–5 μm) were observed throughout the study period, but larger organisms (>8 μm) such as the cyanobacteria Planktolyngbya limnetica occurred only during the warmest period (January). Only few individuals of metazoans (rotifers) were found in planktonic samples. Due to deep light penetration (10–15% of incoming active solar radiation reached the depth of 30 m), thick cyanobacterial mats (30 cm) cover all the bottom surface (grey silts) in the lake. Abundant benthic biota associated with these mats was found (up to 1000 ind. m^?2). Among the benthic metazoans, bdelloid rotifers and tardigrades were the dominating taxa. The results of this study suggest a typical ecological feature of most subglacial lakes in East Antarctica is that metazoans are very poor in the pelagic zone, preferring instead to occupy an area near the lake bottom because of a favourable constant temperature of 4 °C, good level of dissolved oxygen and available food resources as the bacterial detritus.