bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of calcium on the evolution of nitrogen during pyrolysis of a typical low rank coal
Authors: Lin Xiongchao , Yang Sasha , Chen Xujun , Zheng Panpan , Wang Yonggang , Zhang Shu 
Published: December 2019

AbstractThis study aims to investigate the effects of calcium on the migration of nitrogen in coal (coal-N) to N-containing gas species, particularly, NH3 and HCN (volatile-N) in volatiles, as well as the chemical transformation of the N in char during coal pyrolysis under different temperatures. The pyrolysis experiments of Shengli brown coal and its derived coal samples loaded with different contents of calcium were conducted under 600–800 °C in a novel fluidized bed reactor. The experimental results showed that during coal pyrolysis, the generation of NH3 is mainly derived from secondary reactions among volatiles, tar and char with the catalytic effect of mineral matter, especially calcium in coal. Increasing pyrolysis temperature from 600 to 800 °C could enhance the release of N in coal to volatiles. Meanwhile, the increased pyrolysis temperature could also inhibit the generation of NH3 while facilitating the formation of HCN. The release of HCN is more sensitive to pyrolysis temperatures. Specifically, under higher pyrolysis temperatures, more N-containing structures in coal would become thermally unstable and crack into HCN; On the other hand, higher pyrolysis temperature could also enhance the decomposition of N in coal to N-containing species in tar or N2, thus reducing the release of HCN and NH3. Nitrogen in tar could either undergo secondary decomposition reactions, generating NH3, HCN, N2 and other N-containing species in gas phase, or experience condensation polymerization by forming macromolecular structure and be retained in char at high pyrolysis temperatures. Calcium could significantly restrain the release of N from coal, thus reducing the yields of NH3 and HCN. During coal pyrolysis, calcium catalytically enhances the fracture and combination of chemical bonds, generating abundant free radicals. These free radicals could continuously attack N-containing structures and consequently release the N-containing gaseous products, such as NH3, HCN, N2 etc., resulting in the decrease of N in char. Calcium also plays important roles in nitrogen transformation in char during coal pyrolysis by catalytically intensifying the transformation of N in char from pyridinic nitrogen (N-6) and pyrrolic nitrogen (N-5) to quaternary type nitrogen (N-Q) during coal pyrolysis.
A practical application of game theory to optimize selection of hardware Trojan detection strategies
Authors: Graf Jonathan , Batchelor Whitney , Harper Scott , Marlow Ryan , Carlisle Edward , Athanas Peter 
Published: December 2019

AbstractA wide variety of Hardware Trojan countermeasures have been developed, but less work has been done to determine which are optimal for any given design. To address this, we consider not only metrics related to the performance of the countermeasure, but also the likely action of an adversary given their goals. Trojans are inserted by an adversary to accomplish an end, so these goals must be considered and quantified in order to predict these actions. The model presented here builds upon a security economic approach that models the adversary and defender motives and goals in the context of empirically derived countermeasure efficacy metrics. The approach supports formation of a two-player strategic game to determine optimal strategy selection for both adversary and defender. A game may be played in a variety of contexts, including consideration of the entire design lifecycle or only a step in product development. As a demonstration of the practicality of this approach, we present an experiment that derives efficacy metrics from a set of countermeasures (defender strategies) when tested against a taxonomy of Trojans (adversary strategies). We further present a software framework, GameRunner, that automates not only the solution to the game but also mathematical and graphical exploration of “what if” scenarios in the context of the game. GameRunner can also issue “prescriptions,” a set of commands that allows the defender to automate the application of the optimal defender strategy to their circuit of concern. Finally, we include a discussion of ongoing work to include additional software tools, a more advanced experimental framework, and the application of irrationality models to account for players who make subrational decisions.
Understanding Catchment‐Scale Forest Root Water Uptake Strategies Across the Continental United States Through Inverse Ecohydrological Modeling
Authors: Knighton James , Singh Kanishka , Evaristo Jaivime 
Published: December 2019

AbstractTrees influence the partitioning of water between catchment water yield and evapotranspiration through mediation of soil water via root water uptake (RWU). Recent research has estimated the depth of RWU for a variety of tree species at plot scales with measurements of stable isotopes in water and sap flux. Though informative, there are some challenges bridging the gap between plot‐ and catchment‐scale water fluxes. We estimated catchment‐scale tree RWU behavior for 139 forested catchments across the continental United States from continuous streamflow records with inverse ecohydrological modeling. Our catchment‐scale RWU estimates agreed well with existing plot‐scale research. Monoculture catchments dense with trees reliant on shallow soil water exhibited reduced transpiration losses compared to deep‐rooted and mixed‐species forests within the Budkyo framework. This research highlights the importance of representing plant characteristics that define RWU control of transpiration in land surface and earth systems models.
Tropical Variability Simulated in ICON‐A With a Spectral Cumulus Parameterization
Authors: Baba Yuya , Giorgetta Marco A. 
Published: December 2019

AbstractWe implemented a spectral cumulus parameterization based on a cloud‐resolving model (SC scheme) in the icosahedral nonhydrostatic atmospheric model (ICON‐A). We compared the resulting simulated climatology and tropical variability with results from the standard version of ICON‐A using a variant of the Tiedtke‐Nordeng scheme (TK scheme) using observational and reanalysis data. The climatological errors of the SC scheme were similar to those of the TK scheme, but several biases, such as properties of meridional winds and precipitation pattern in the western Pacific, were much improved. For tropical variability, we found that the SC scheme improved the interannual response of the precipitation in the western Pacific and was able to simulate Madden‐Julian oscillation (MJO) features much better than the TK scheme. We investigated the reason for the better simulation of the MJO using composite analysis and column process analysis for moisture. Our results suggest that the entrainment parameterization of the SC scheme is necessary to reproduce the MJO; however, spectral representation and improved convective closure are also found to contribute for better MJO simulation. These parameterizations improved moisture supply from low‐level clouds and cloud mass flux which were needed to sustain the MJO.
An Energy Consistent Discretization of the Nonhydrostatic Equations in Primitive Variables
Authors: Taylor Mark A. , Guba Oksana , Steyer Andrew , Ullrich Paul A. , Hall David M. , Eldred Christopher 
Published: December 2019

AbstractWe derive a formulation of the nonhydrostatic equations in spherical geometry with a Lorenz staggered vertical discretization. The combination conserves a discrete energy in exact time integration when coupled with a mimetic horizontal discretization. The formulation is a version of Dubos and Tort (2014, https://doi.org/10.1175/MWR-D-14-00069.1) rewritten in terms of primitive variables. It is valid for terrain following mass or height coordinates and for both Eulerian or vertically Lagrangian discretizations. The discretization relies on an extension to Simmons and Burridge (1981, https://doi.org/10.1175/1520-0493(1981)109<0758:AEAAMC>2.0.CO;2) vertical differencing, which we show obeys a discrete derivative product rule. This product rule allows us to simplify the treatment of the vertical transport terms. Energy conservation is obtained via a term‐by‐term balance in the kinetic, internal, and potential energy budgets, ensuring an energy‐consistent discretization up to time truncation error with no spurious sources of energy. We demonstrate convergence with respect to time truncation error in a spectral element code with a horizontal explicit vertically implicit implicit‐explicit time stepping algorithm.
Time-resolved interference microscopy for studying nonideal plasma formed by high-power femtosecond laser pulses
Authors: Sitnikov D S 
Published: December 2019

Abstract
Measurement results of characteristic size of plasma density inhomogeneity on the surface of bulk iron target formed under action of femtosecond laser pulses with intensity of 1016 W/cm2 are presented. Investigations are performed using time-resolved interference microscopy technique. Femtosecond laser pulses with high time contrast of 107 generated by chromium:forsterite laser system are applied. Efficacy of the chosen technique is demonstrated; the size of plasma inhomogeneity is shown to be less than 30 nm.
Application of hyperspectral imaging for analysis of embryonic development of lower vertebrates
Authors: Burlakov A B , Shirokov S V , Khokhlov D D , Kuzmin V I , Gadzaov A F 
Published: December 2019

Abstract
The task of analyzing the characteristics of the embryonic development of lower vertebrates using non-invasive optical methods is considered. We propose to apply hyperspectral imaging for segmentation of embryo zones with different physical and chemical properties. This approach allows one to obtain information on the spatial distribution of optical spectral properties of the observed object. An experimental setup based on a microscope coupled with a spectral imaging add-on module utilizing a tunable acousto-optic filter has been created to implement this approach. Hyperspectral data arrays are formed as a series of spectral narrowband images obtained by successive tuning of the acousto-optic filter within the working spectral range. A series of experiments was conducted in which the development of embryos of the Misgurnus fossilis loach during their transition from the 32nd to the 33rd developmental stage was observed using the described experimental setup. Characteristic spatial regions corresponding to certain parts of the loach embryo were identified. The time dependences characterizing the change in the spectral properties of the selected regions were obtained. It is shown that joint processing of a series of spectral images obtained in different spectral bands within the working spectral range of an acousto-optical spectral imaging module allows one to effectively identify differences in the kinetics of the optical transmission spectral density for various regions of the axial mesoderm.
Numerical simulation of supersonic flow around a cone in a three-dimensional formulation in the software package OpenFOAM
Authors: Kuvshinnikov A E 
Published: December 2019

AbstractThree solvers of the OpenFOAM package are chosen to numerically solve the problem of supersonic flow around a cone. The cone half-angle and the angle of attack varied. The obtained results are compared with the well-known numerical solution of this problem. It has been established that the rhoCentralFoam solver provides minimal error for the pressure field and pisoCentralFoam solver for velocity field.
Experimental observation of turbulent exchange between heterogeneous vortex ring and surrounding medium by the shadowgraph method
Authors: Nikulin V V , Panenko R A 
Published: December 2019

Abstract
A shadow visualization of turbulent exchange between vortex ring containing fluid less dense than that out of it and surrounding medium is performed. A characteristic distance and time of this process are determined and the dependence of time on both vortex velocity and the related Reynolds number is obtained. Using characteristic time, the turbulent diffusion coefficient in the vortex atmosphere is estimated.
Investigation of temperature field of weakly ionized gas jet by the background oriented schlieren method
Authors: Korotkikh I I , Malakhov Yu I , Kuchmenko A V 
Published: December 2019

Abstract
The paper shows the possibility of using the background oriented schlieren technique to study the temperature field of a weakly ionized plasma jet created as a result of a spark discharge in argon at atmospheric pressure. The design of the spark source, the experimental setup, the experimental method and the processing of experimental data are presented. The temperature field of weakly ionized plasma jet and the temperature distribution around it were obtained.
Researches of two-phase stream by methods of registration of fluorescence of drops of liquid and Shadowgraph
Authors: Chelebyan O G , Vasilyev A Y , Sviridenkov A A , Loginova A A 
Published: December 2019

Abstract
In this paper, the fluorescent method is used in conjunction with the shadowgraph method to obtain the concentration distributions and droplet sizes in the spray. A beam of light from a pulsed laser, passing through a longitudinal or cross-section of a jet of atomized fuel, tinted with a fluorescent additive, oxyquinoline, partially scatters on droplets (Mi-scattering), while blue light with a wavelength λ = 488 nm excites fluorescence in the green range of the wavelength spectrum. A color image of the cross section of the fuel spray by a laser beam is recorded during scanning by a digital camera, the optical axis of which is directed at a right angle to the axis of the laser beam. Thus, at each point of the image of the spray cross section, fluorescence intensities are recorded, proportional to the volume concentration of the droplets and vertically polarized by the component scattered on the light drops with respect to the scattering plane (measurement). The ratio of fluorescence intensity to Mie scattering intensity is proportional to the diameter of the fuel droplets averaged over the Sauter.
Optical study of the concentration and particle size distribution of octadecylamine in water
Authors: Skornyakova N M , Anikeev A V , Parshin V A 
Published: December 2019

Abstract
The objective of this study was to determine the size of the investigated particles in water. The particles studied were octadecylamine inclusions which are invisible to the naked eye. To increase the accuracy of the results obtained, the study was carried out using two optical methods: direct video surveillance in a digital stereo microscope and laser diffraction method.
The choice of an image processing algorithm for increasing sensitivity of the surface plasmon resonance method
Authors: Pavlov I N , Vedyashkina A V , Yanina G M 
Published: December 2019

Abstract
The paper describes the principles of the surface plasmon resonance imaging method in application to investigation of heat and mass transfer processes. It is shown, that one the main obstacles to increase its sensitivity is low signal-to-noise ratio due to speckles and stray interference structures in the experimental images. An algorithm of image processing is developed to overcome this obstacle. Several ways to do it is discussed in the paper.
In-plane interferometry of terahertz surface plasmon polaritons
Authors: Nikitin A K , Khitrov O V , Gerasimov V V , Khasanov I Sh , Ryzhova T A 
Published: December 2019

Abstract
The paper is devoted to the development of interferometric schemes for determining the complex refractive index κ = κ′+i·κ″ κ of surface plasmon-polaritons (SPPs) of the terahertz (THz) spectral range. As the value of κ depends on the dielectric constant εm
of the metal surface guiding the SPPs it can be used for determining ϵm
in the far infrared what other optical methods fail to do due to high reflectivity of metals. We discuss two types of THz SPP interferometers in which the interference pattern is formed as a result of the interaction of SPP beams themselves rather than bulk waves produced by these beams. The first type of interferometers are static devices that enable one to investigate fast processes on the metal surface, while the second type are dynamic ones that make it possible to realize Fourier spectroscopy of the metal surface and its transition layer at THz frequencies. Devices of the both types produce interferograms enabling one to determine the real and the imaginary parts of κ. The results of experiments on the interaction of THz SPPs with flat mirrors and beam – splitting plates, the key elements of the THz SPP interferometers, are presented.
Long-focus low-cost lens deigned for biomedical hyperspectral camera
Authors: Batshev V I , Gavlina A E 
Published: December 2019

Abstract
In this work a design of 250 mm F/20 lens for hyperspectral imaging of biomedical micro objects is presented. The designed lens consists of only standard optical elements and does not contain any newly developed component. Its low aperture and small field of view causes that image quality is limited only by diffraction and two optical aberrations – field curvature and chromatic focal shift. That is why an achromatic doublet is utilized as a basic lens component. Its residual field curvature is corrected by a Smith lens – a single plane-concave lens located near the image plane. The components are selected from commercially available ones. A distance between components was the only optimized parameter. Such layout makes the lens cheap and easy to manufacture.
Applying PIV to study a fluid flow in the vicinity of a circular streamlined cylinder
Authors: Dobroselsky K G 
Published: December 2019

Abstract
The round cylinder streamlining by a turbulent water flow in a hydrodynamic pipe is investigated experimentally. Using the optical method of PIV (Particle Image Velocimetry) the averaged velocity fields near the cylinder are obtained and, on their basis, the geometric characteristics of the vortex zone of the near wake are calculated for the non-cavitation and cavitation flow regimes in the critical region of Reynolds numbers. The use of two mirrors, set at a certain angle to each other, allows obtaining a picture of the velocity fields around the entire cylinder, rather than around half of it, as it is done in most of the works. Using vector patterns of averaged velocity fields, the angles of the boundary layer separation from the cylinder surface along the reverse flow are determined in the considered flow regimes. An asymmetrical separation of the boundary layer from different sides of the streamlined cylinder was obtained. It is shown that the increase in the Reynolds number for the non-cavitation flow regimes leads to a more than two times decrease in the vortex zone behind the cylinder, and, accordingly, to a displacement of the separation angles downstream. Cavitation increases the vortex zone behind the cylinder and displaces the separation angles upstream.
Development of a cylindrical acoustic lens to control the amplitude and phase characteristics of optical radiation
Authors: Bykhanov A N 
Published: December 2019

Abstract
The promising method of light beam phase control based on beam transmission through the medium layer perturbed with acoustid wave generated by the lateral surface “lens”, requives the exact calculation of the acoustic field inside cylindrical cavity of the “lens”. We use the comm program Comsol for calculation and demonstrate that for the axial symmetric cylinder, which was used as a test object, the calculated distribution very close coinsides with theoretical form resulted from acoustic equations solutions.
Application of acoustic emission and laser optoacoustics at various stages of defect formation during friction stir welding
Authors: Stepanova K , Kinzhagulov I , Yakovlev Y 
Published: December 2019

Abstract
This paper covers basic aspects of laser ultrasound and acoustic emission non-destructive testing methods in application of monitoring friction stir welds during its deformation and fracture. Stress-strain curves for such welds were obtained and the mechanical characteristics of welded joints of aluminum-magnesium alloy were determined. Using acoustic elastic effect levels of mechanical stresses were measured. Signals of acoustic emission, stimulated by one-axis loading, were registered and analyzed. It was established that acoustic emission during deformation and fracture of samples of welded joints is associated with the course of the process of plastic flow of the material. The nature of the distribution of acoustic emission parameters in the destruction of welded joints with defects has distinctive features. In conditions of one axis quasi static loading rate event count acoustic emission is the most informative parameter.
Development of the system for quantitative gas-liquid flow visualization
Authors: Kuchmenko A V , Koshelev D A , Skornyakova N M , Shcherbakov P P 
Published: December 2019

Abstract
The paper is concerned with the developing of an optical-electronic complex for visualization and quantification of the gas-liquid flow from the nozzle using the particle image velocimetry method depending on various flow parameters. Selection of optical elements for experimental research was based on the possibility of visualizing the flow, determining its type, opening angle, and also obtaining vector velocity fields in the plane under study, on the basis of which the gas-liquid flow drops velocities dependencies on the coordinates in given sections of the vector field were constructed.
Visualization of plasma fluxes by a measurement of own rotation of a dust particle
Authors: Dzlieva E S , Karasev V Yu , Krylov I R , Mashek I Ch , Novikov L A , Pavlov S I 
Published: December 2019

Abstract
A research of own rotation of single dust particle which is in a dust trap in the stratified glow discharge under imposed magnetic field is carried out. It is experimentally shown that in the scale of Debye length an action of azimuthal torque from the fluxes of ions and electrons is mutually compensated; an angular velocity of rotation of dusty particle remains invariable up to magnetic fields of 200 G. The found effect was given theoretical interpretation on a basis of consideration of ambipolar diffusion of positive ions and electrons to the particle surface.
Special features of laser diagnostics of gas flows in a thick-walled glass pipe
Authors: Lapitskiy K M , Poyatsyka D A , Lapitskaya I A , Poroykov A Yu , Ilina N S 
Published: December 2019

Abstract
The article presents application of optical gradient methods for the research of inhomogeneity of gas flows through a thick-walled glass cylinder. The influence of not only inhomogeneous gas medium, but also cylinder walls on the process of laser radiation propagation was researched. Methods for describing the refraction of the laser sheet for various cases of its orientation in space in geometrical optics approximation were worked out. The analysis of displacement of the laser sheet’s sections on the screen after penetration through inhomogeneity was conducted. Calculations of the laser sheet’s shape distortion during penetration through a transparent hollow cylinder were performed. Theoretical distributions of the laser sheet’s sections on the screen were constructed. Various cases of the laser sheet orientation in space were considered. The influence of an optically inhomogeneous medium on the laser sheet’s shape were considered.
Development of a series of interchangeable optical tips for a video endoscope
Authors: Batshev V I , Machikhin A S , Gorevoy A V , Khokhlov D D 
Published: December 2019

Abstract
In this work a design of four different optical tips for video endoscope is presented. In particular, the report presents the results of the calculation of optical systems with normal (50˚) and wide (80˚) field of view (FoV) for direct (0˚) and side (90˚) view. All tips have simple to manufacture design and produce good image quality. The results of image simulation are presented.