bluuebunny/crossref_metadata_2025 huggingface dataset:
The transmembrane autophagy cargo receptors ATI1 and ATI2 interact with ATG8 through intrinsically disordered regions with distinct biophysical properties
Authors: Sjøgaard Ida Marie Zobbe , Bressendorff Simon , Prestel Andreas , Kausika Swathi , Oksbjerg Emilie , Kragelund Birthe B. , Brodersen Peter
Published: January 2019

Selective autophagy has emerged as an important mechanism by which eukaryotic cells control the abundance of specific proteins. This mechanism relies on cargo recruitment to autophagosomes by receptors that bind to both the ubiquitin-like AUTOPHAGY8 (ATG8) protein through ATG8-interacting motifs (AIMs) and to the cargo to be degraded. In plants, two autophagy cargo receptors, ATG8-interacting protein 1 (ATI1) and 2 (ATI2), were identified early on, but their molecular properties remain poorly understood. Here, we show that ATI1 and ATI2 are transmembrane proteins with long N-terminal intrinsically disordered regions (IDRs). The N-terminal IDRs contain the functional AIMs, and we use nuclear magnetic resonance spectroscopy to directly observe the disorder-order transition of the AIM upon ATG8 binding. Our analyses also show that the IDRs of ATI1 and ATI2 are not equivalent, because ATI2 has properties of a fully disordered polypeptide, while ATI1 has properties more consistent with a collapsed pre-molten globule-like conformation, possibly as a consequence of a higher content of π-orbital-containing amino acid residues. Finally, we show that a sizable fraction of ATI2, but not ATI1, is phosphorylated in planta.
The essential role of tumor suppressor gene ING4 in various human cancers and non-neoplastic disorders
Authors: Du Yang , Cheng Yan , Su Guanfang
Published: January 2019

Inhibitor of growth 4 (ING4), a member of the ING family discovered in 2003, has been shown to act as a tumor suppressor and is frequently down-regulated in various human cancers. Numerous published in vivo and in vitro studies have shown that ING4 is responsible for important cancer hallmarks such as pathologic cell cycle arrest, apoptosis, autophagy, contact inhibition, and hypoxic adaptation, and also affects tumor angiogenesis, invasion, and metastasis. These characteristics are typically associated with regulation through chromatin acetylation by binding histone H3 trimethylated at lysine 4 (H3K4me3) and through transcriptional activity of transcription factor P53 and NF-κB. In addition, emerging evidence has indicated that abnormalities in ING4 expression and function play key roles in non-neoplastic disorders. Here, we provide an overview of ING4-modulated chromosome remodeling and transcriptional function, as well as the functional consequences of different genetic variants. We also present the current understanding concerning the role of ING4 in the development of neoplastic and non-neoplastic diseases. These studies offer inspiration for pursuing novel therapeutics for various cancers.
LncRNA TP73-AS1 sponges miR-141-3p to promote the migration and invasion of pancreatic cancer cells through the up-regulation of BDH2
Authors: Cui Xian-Ping , Wang Chuan-Xi , Wang Zhi-Yi , Li Jian , Tan Ya-Wen , Gu Song-Tao , Qin Cheng-Kun
Published: January 2019

LncRNA TP73 antisense RNA 1T (TP73-AS1) plays an important role in human malignancies. However, the levels of TP73-AS1 and its functional mechanisms in pancreatic cancer metastasis remain unknown, and the clinical significance of TP73-AS1 in human pancreatic cancer is also unclear. In the present study, the levels of TP73-AS1 and its candidate target miR-141 in pancreatic cancer and adjacent normal tissue were detected using qRT-PCR. The association between TP73-AS1 levels and the clinicopathologic characteristics of pancreatic cancer patients were analyzed. The relationship between TP73-AS1 and miR-141, and miR-141 and its candidate target 3-hydroxybutyrate dehydrogenase type 2 (BDH2) was confirmed using dual-luciferase reporter assays. TP73-AS1 and/or miR-141 were knocked down using siRNA or an inhibitor in pancreatic cancer cells and cell migration and invasion then examined. The results showed that TP73-AS1 was up-regulated in pancreatic cancer tissue and cell lines. High levels of TP73-AS1 were correlated with poor clinicopathological characteristics and shorter overall survival. MiR-141 was a direct target for TP73-AS1, while BDH2 was a direct target for miR-141. The knockdown of TP73-AS1 significantly inhibited the migration and invasion of pancreatic cancer cells, while the miR-141 inhibitor significantly restored the migration and invasion. Therefore, TP73-AS1 positively regulated BDH2 expression by sponging miR-141. These findings suggest that TP73-AS1 serves as an oncogene and promotes the metastasis of pancreatic cancer. Moreover, TP73-AS1 could serve as a predictor and a potential drug biotarget for pancreatic cancer.
The GTC exoplanet transit spectroscopy survey
Authors: Murgas F. , Chen G. , Pallé E. , Nortmann L. , Nowak G.
Published: January 2019

Context. Rayleigh scattering in a hydrogen-dominated exoplanet atmosphere can be detected using ground- or space-based telescopes. However, stellar activity in the form of spots can mimic Rayleigh scattering in the observed transmission spectrum. Quantifying this phenomena is key to our correct interpretation of exoplanet atmospheric properties.

Aims. We use the ten-meter Gran Telescopio Canarias (GTC) telescope to carry out a ground-based transmission spectra survey of extrasolar planets to characterize their atmospheres. In this paper we investigate the exoplanet HAT-P-11b, a Neptune-sized planet orbiting an active K-type star.

Methods. We obtained long-slit optical spectroscopy of two transits of HAT-P-11b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) on August 30, 2016 and September 25, 2017. We integrated the spectrum of HAT-P-11 and one reference star in several spectroscopic channels across the λ ~ 400–785 nm region, creating numerous light curves of the transits. We fit analytic transit curves to the data taking into account the systematic effects and red noise present in the time series in an effort to measure the change of the planet-to-star radius ratio (Rp∕Rs) across wavelength.

Results. By fitting both transits together, we find a slope in the transmission spectrum showing an increase of the planetary radius towards blue wavelengths. Closer inspection of the transmission spectrum of the individual data sets reveals that the first transit presents this slope while the transmission spectrum of the second data set is flat. Additionally, we detect hints of Na absorption on the first night, but not on the second. We conclude that the transmission spectrum slope and Na absorption excess found in the first transit observation are caused by unocculted stellar spots. Modeling the contribution of unocculted spots to reproduce the results of the first night we find a spot filling factor of δ = 0.62−0.17+0.20 and a spot-to-photosphere temperature difference of ΔT = 429−299+184 K.
An estimate of the k2 Love number of WASP-18Ab from its radial velocity measurements
Authors: Csizmadia Sz. , Hellard H. , Smith A. M. S.
Published: January 2019

Context. Increasing our knowledge of the interior structure, composition, and density distribution of exoplanets is crucial to make progress in the understanding of exoplanetary formation, migration and habitability. However, the directly measurable mass and radius values offer little constraint on interior structure, because the inverse problem is highly degenerate. Therefore, there is a clear need for a third observable of exoplanet interiors. This third observable can be the k2 fluid Love number which measures the central mass concentration of an exoplanet.

Aims. The aims of this paper are (i) to develop a basic model to fit the long-term radial velocity and TTV variations caused by tidal interactions, (ii) to apply the model to the WASP-18Ab system, and (iii) to estimate the Love number of the planet.

Methods. Archival radial velocity, transit and occultation timing data were collected and fitted using the model introduced here.

Results. The best model fit to the archival radial velocity and timing data of WASP-18Ab was obtained with a Love number of the massive (~10 MJup) hot Jupiter WASP-18Ab: k2,Love = 0.62−0.19+0.55. This causes apsidal motion in the system, at a rate of ~0.0087 ± 0.0033°∕days ≊ 31.3 ± 11.8 arcsec day−1. When checking possible causes of periastron precession, other than the relativistic term or the non-spherical shape of the components, we found a companion star to the WASP-18 system, named WASP-18B which is a probable M6.5V dwarf with ~0.1 M⊙ at 3519 AU distance from the transit host star. We also find that small orbital eccentricities may be real, rather than an apparent effect caused by the non-spherical stellar shape.
CHANG-ES
Authors: Stein Y. , Dettmar R.-J. , Irwin J. , Beck R. , Weżgowiec M. , Miskolczi A. , Krause M. , Heesen V. , Wiegert T. , Heald G. , Walterbos R. A. M. , Li J.-T. , Soida M.
Published: January 2019

Context. The observation of total and linearly polarized synchrotron radiation of spiral galaxies in the radio continuum reveals the distribution and structure of their magnetic fields. By observing these, information about the proposed dynamo processes that preserve the large-scale magnetic fields in spiral galaxies can be gained. Additionally, by analyzing the synchrotron intensity, the transport processes of cosmic rays into the halo of edge-on spiral galaxies can be investigated.

Aims. We analyze the magnetic field geometry and the transport processes of the cosmic rays of the edge-on spiral starburst galaxy NGC 4666 from CHANG-ES radio data in two frequencies; 6 GHz (C-band) and 1.5 GHz (L-band). Supplementary X-ray data are used to investigate the hot gas in NGC 4666.

Methods. We determine the radio scale heights of total power emission at both frequencies for this galaxy. We show the magnetic field orientations derived from the polarization data. Using rotation measure (RM) synthesis we further study the behavior of the RM values along the disk in C-band to investigate the large-scale magnetic-field pattern. We use the revised equipartition formula to calculate a map of the magnetic field strength. Furthermore, we model the processes of cosmic-ray transport into the halo with the 1D SPINNAKER model.

Results. The extended radio halo of NGC 4666 is box-shaped and is probably produced by the previously observed supernova-driven superwind. This is supported by our finding of an advective cosmic-ray transport such as that expected for a galactic wind. The scale-height analysis revealed an asymmetric halo above and below the disk as well as between the two sides of the major axis. A central point source as well as a bubble structure is seen in the radio data for the first time. Our X-ray data show a box-shaped hot halo around NGC 4666 and furthermore confirm the AGN nature of the central source. NGC 4666 has a large-scale X-shaped magnetic field in the halo, as has been observed in other edge-on galaxies. The analysis furthermore revealed that the disk of NGC 4666 shows hints of field reversals along its radius, which is the first detection of this phenomenon in an external galaxy.
Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code
Authors: Masseron T. , García-Hernández D. A. , Mészáros Sz. , Zamora O. , Dell’Agli F. , Allende Prieto C. , Edvardsson B. , Shetrone M. , Plez B. , Fernández-Trincado J. G. , Cunha K. , Jönsson H. , Geisler D. , Beers T. C. , Cohen R. E.
Published: January 2019

Aims. We seek to provide abundances of a large set of light and neutron-capture elements homogeneously analyzed that cover a wide range of metallicity to constrain globular cluster (GC) formation and evolution models.

Methods. We analyzed a large sample of 885 GCs giants from the SDSS IV-Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. We used the Cannon results to separate the red giant branch and asymptotic giant branch stars, not only allowing for a refinement of surface gravity from isochrones, but also providing an independent H-band spectroscopic method to distinguish stellar evolutionary status in clusters. We then used the Brussels Automatic Code for Characterizing High accUracy Spectra (BACCHUS) to derive metallicity, microturbulence, macroturbulence, many light-element abundances, and the neutron-capture elements Nd and Ce for the first time from the APOGEE GCs data.

Results. Our independent analysis helped us to diagnose issues regarding the standard analysis of the APOGEE DR14 for low-metallicity GC stars. Furthermore, while we confirm most of the known correlations and anticorrelation trends (Na-O, Mg-Al, C-N), we discover that some stars within our most metal-poor clusters show an extreme Mg depletion and some Si enhancement. At the same time, these stars show some relative Al depletion, displaying a turnover in the Mg-Al diagram. These stars suggest that Al has been partially depleted in their progenitors by very hot proton-capture nucleosynthetic processes. Furthermore, we attempted to quantitatively correlate the spread of Al abundances with the global properties of GCs. We find an anticorrelation of the Al spread against clusters metallicity and luminosity, but the data do not allow us to find clear evidence of a dependence of N against metallicity in the more metal-poor clusters.

Conclusions. Large and homogeneously analyzed samples from ongoing spectroscopic surveys unveil unseen chemical details for many clusters, including a turnover in the Mg-Al anticorrelation, thus yielding new constrains for GCs formation/evolution models.
The dynamic model of agricultural land structure on the space images in the precision agriculture tasks
Authors: Brezhnev Ruslan V. , Maglinets Yuriy A.
Published: January 2019

The study is devoted to the analysis of specific features of spacial objects referred to “agricultural land” class in Central Siberia according to the results of the Earth remote sensing from the space for information support in the precision agriculture tasks. The subject of the study is temporal variability of spectral, textural and geometrical features of a land area with homogenous vegetation (hereinafter agricultural contour). During the vegetation period the agricultural contour is subject to changes caused by a combination of natural and antropogenic factors. These factors are the result of the natural course of vegetation (change of phenological phases), weather conditions and agricultural engineering measures implemented. They typically cause the change of the spacial structure of the agricultural contour resulting in non-homogenous vegetation of an agricultural crop within the agricultural contour.
Remote Sensing Methods for the Retrieval of Inventory and Bioproductivity Parameters of Forests Using High Resolution Satellite Images
Authors: Dmitriev Egor , Kozoderov Vladimir , Donskoy Sergey , Melnik Petr , Sokolov Anton
Published: January 2019

A method for automated processing high spatial resolution satellite images is proposed to retrieve inventory and bioproductivity parameters of forest stands. The method includes effective learning classifiers, inverse modeling, and regression modeling of the estimated parameters. Spectral and texture features are used to classify forest species. The results of test experiments for the selected area of Savvatievskoe forestry (Russia, Tver region) are presented. Accuracy estimates obtained using ground-based measurements demonstrate the effectiveness of using the proposed techniques to automate the process of updating information for the State Forest Inventory program of Russia.
Application of parallel version two-dimensional fast Fourier transform algorithm, analog of the Cooley-Tukey algorithm, for digital image processing of satellite data
Authors: Noskov Mikhail , Tutatchikov Valeriy , Lapchik Mikhail , Ragulina Marina , Yamskikh Tatiana
Published: January 2019

In modern systems of remote sensing two-dimensional fast Fourier transform (FFT) has been widely used for digital processing of satellite images and subsequent image filtering. This article provides a parallel version two-dimensional fast Fourier transform algorithm, analog of the Cooley-Tukey algorithm and its implementation for processing the satellite image of Krasnoyarsk and its suburban areas.
Analysis of GRACE satellite measurements over seismically active areas of the strongest earthquakes
Authors: Simonov Konstantin V. , Kashkin Valentin B. , Rubleva Тatyana V. , Krasnoshekov Konstantin V.
Published: January 2019

The study is devoted to the analysis of the features of the change in the parameter EWH (Equivalent Water Height) over the geoid from the satellite measurements of the GRACE space system in seismically active areas of the strongest underwater earthquakes. The GRACE satellite data archive was created. An interpretation of the disturbed state of the geomedium using digital maps of the spatial distribution of the parameter EWH is performed.
The influence of a strong infrared radiation field on the conductance properties of doped semiconductors
Authors: Barna Imre Ferenc , Pocsai Mihály Anrás , Varró Sándor
Published: January 2019

This work presents an analytic angular differential cross section formula for the electromagnetic radiation field-assisted electron scattering on impurities in semiconductors. These impurities are approximated with various model potentials. The scattered electrons are described with the well-known Volkov wave function, which has been used to describe strong laser field matter interaction for more than half a century, which exactly describes the interaction of the electron with the external oscillating field. These calculations show that the electron conductance in a semiconductor could be enhanced by an order of magnitude if an infrared electromagnetic field is present with 1011 W/cm2 < I < 1013 W/cm2 intensity.
Linear and nonlinear optical properties of WO3 nanoparticles synthesized at different fluences of pulsed Nd:YAG laser
Authors: Fakhari Majid , Torkamany Mohammad Javad , Mirnia Seyed Noureddin
Published: January 2019

Here in this paper, synthesis of WO3 nanoparticles (NPs) by laser ablation of a pure tungsten plate immersed in water is reported. For this purpose, the first harmonic of an acousto-optically Q-Switched Nd:YAG laser is utilized at 13, 18 and 23 J/cm2 laser fluences. X-ray diffraction (XRD) and transmission electron microscopy (TEM) associated with dynamic light scattering (DLS) techniques show that while the laser fluence increases from 13 to 23 J/cm2, the crystallinity, length of particle chains and average particle size of the products increase, respectively. UV–Vis spectra indicate a red shift on the absorption edge towards the visible region for the samples produced at higher laser fluences attributed to the particle size increment and energy band gap decrement, subsequently. Also other linear optical parameters including Urbach energy, refractive index dispersion, relaxation time, complex dielectric and conductivity functions are derived and discussed. Z-scan analysis is carried out to determine the nonlinear refraction index, nonlinear absorption coefficient and third-order nonlinear susceptibility. It is found that WO3 NPs can be considered for optical limiting performance because of the high nonlinear absorption. Furthermore, the specimens prepared at higher laser fluences are more applicable due to the larger particle size and higher nonlinear absorption, consequently.
The modulation of Schottky contacts of p-type graphene-GeC/GeS heterointerface
Authors: Li Honglin , Cui Yuting , Luo Haijun
Published: January 2019

n-Type contact of Schottky barriers at two-dimensional (2D) materials/metal interfaces is a usual formalization in the modern FETs applications. It is common to modulate it from n- to p-type through some specific methods. In this work, we came up with two new intrinsic p-type contacts of graphene-GeC/GeS and further tune them from p-type to n-type by external electric fields. It proved that the electronic properties of graphene and GeC/GeS can be roughly preserved for the weak van der Waals (vdW) interaction. p-Type contacts with relatively small barriers are formed at g-GeC/GeS heterointerfaces. After external electric field applied, the Schottky barrier can be effectively tuned by different external electric and the p-type contact further turns into n-type. Variation of the Schottky barriers indicated a partial pinning for interfaces of g-GeC/GeS. This is because the interfacial states between graphene and GeC/GeS hardly exists. The barrier height of g-GeC/GeS and the corresponding contact type can be flexibly tuned, which is of great importance in the design of novel transistors-based 2D materials. Searching for novel nanoscale electronic equipment based on 2D materials is a hot topic in the current study. This work would provide meaningful guidelines for nanoscale devices.
The nucleate boiling in a droplet of aqueous salt solution
Authors: Misyura Sergey , Meleshkin Anton
Published: January 2019

This paper is devoted to an experimental study of the dynamics of the nucleate boiling in a droplet of aqueous solution of LiBr salt. As the concentration of LiBr salt increases, the growth rate of the bubbles decreases and the boiling completely stops when a high salt concentration is reached. An increase in the concentration of salt in the liquid layer of the bottom of the bubble leads to a decrease in the rate of increase in the diameter of the bubble, and a dry spot is not formed. The growth rate of a bubble (v) in a water droplet is somewhat higher than one for a salt solution for t > 0.2-0.3 s. The difference of v for the salt solution from curve 3 increases sharply when t < 0.1 s. For the first time, four regimes of the nucleate boiling in LiBr solution droplet were detected.
Oxidation of ablated silicon during pulsed laser deposition in a background gas with different oxygen partial pressures
Authors: Starinskiy Sergey V. , Rodionov Alexey A. , Shukhov Yuri G. , Bulgakov Alexander V.
Published: January 2019

We have analysed changes in the oxidation state of SiOx films produced by pulsed laser deposition in a background gas with different partial pressures of oxygen. The optical properties of the films in IR range are shown to be close to those of SiO2 while the total oxidation degree is considerably less than 2. It is suggested that the film consists of oxidized and unoxidized regions due to preferential oxidation of the periphery of the silicon ablation plume during expansion. These regions are overlapping in the film if the laser beam is scanned on the target.
Simulation of steady-state cuttings transport through a horizontal annulus channel
Authors: Ignatenko Yaroslav , Gavrilov Andrey , Bocharov Oleg , May Roland
Published: January 2019

The current study is devoted to simulating cuttings transport by drilling fluid through a horizontal section of borehole with an annular cross section. Drill pipe rotates in fixed eccentric position. Steady-state flow is
considered. Cuttings are rigid spheres with equal diameters. The carrying fluid is drilling mud with Herschel-Bulkley rheology. Suspension rheology depends on local shear rate and particles concentration. Continuous mixture model with algebraic equation for particles slipping velocity is used. Two hydrodynamic regimes are considered: axial flow without drill pipe rotation and with drill pipe rotation. In the case of axial flow was shown that increasing of power index n and consistency factor k increases pressure gradient and decreases cuttings concentration. Increasing of yield
stress leads to increasing of pressure gradient and cuttings concentration. Cuttings concentration achieves constant value for high yield stress and not depends on it. Rotation of the drill pipe significantly changes the flow
structure: pressure loss occurs and particles concentration decreases in the cross section. Two basic regimes of rotational flow are observed: domination of primary vortex around drill pipe and domination secondary vorticity structures. Transition between regimes leads to significant changes of flow integral parameters.
Analysis of statistical data on drop collisions in an aerosol flow during experiments
Authors: Antonov Dmitry , Vysokomornaya Olga , Piskunov Maxim , Shlegel Nikita
Published: January 2019

The study presents a software code developed by using Mathematica. This code allows the automatic analysis of breakup
consequences of heterogeneous drops. Moreover, we show how statistical data on drop collisions in a sprayed aerosol flow can be collected using this code. For this purpose, we have compared results of manual handling of video with automatic one.
Experimental and numerical investigation of excitation of artificial disturbances in the supersonic boundary layer
Authors: Yatskikh Aleksey , Semenov Aleksander , Kolosov Gleb , Kosinov Aleksander , Yermolaev Yury
Published: January 2019

The influence of the parameters of the impulse action on the laminar supersonic flat-plate boundary layer on the excited localized perturbations is investigated at Mach 2. The influence of the duration of a pulsed discharge on the generated disturbances is studied experimentally. Also, a direct numerical simulation of the influence of the parameters of pulse injection on generated perturbations is carried out. It is obtained that as the duration of the action on the supersonic boundary layer increases, the amplitude of the generated disturbance increases. The velocity of the
propagation downstream of localized disturbances in Mach 2 supersonic flat-plate boundary layer is estimated.
Validation of a CFD model of a single stage centrifugal compressor by mass-averaged parameters
Authors: Bogdanets Sergey , Blinov Vitaly , Sedunin Viacheslav , Komarov Oleg , Skorohodov Alexander
Published: January 2019

In this paper a validation of a computational model is presented for single-stage centrifugal compressor with an axial-flow impeller and a vaneless diffuser. The comparison was made by mass averaged performance. The paper shows that the model used is able to predict overall performance near the design operating point within 1.2% difference. However, further away the model fails to follow the experimental characteristics.
Influence of spatial inhomogeneity of environment temperature on temperature oscillations and thermocyclic stresses in elastic half-space
Authors: Supel’nyak Maxim
Published: January 2019

Elastic half-space on which surface the heat transfer follows the Newton-Richmann law where enviroment temperature is a periodic function of time and spatial variable is investigated. A temperature field and a stressed deformed state of half-space is found after the solution of a quasistatic problem of thermoelasticity. The solution is received in the form of double Fourier series.
Simulating the boiling fluid outflow taking into account external condensation
Authors: Alekseev Maksim , Vozhakov Ivan , Lezhnin Sergey
Published: January 2019

This paper considers the axisymmetric problem of condensation at a boiling liquid outflow in a closed region filled with steam. It has been found that the unsteady condensation is due to the formation of a complex structure of lateral pressure surges, Mach disk, barrel shocks and a wall, on which the pressure exceeds the local saturation pressure.
Resistance force pulsations of annular flow in the Couette-Taylor system with counter-rotating cylinders
Authors: Miskiv Nikolay , Serov Anatoly , Nazarov Aleksandr , Mamonov Valery
Published: January 2019

The paper presents the results of an experimental study of the Couette-Taylor flow fluctuations in a ring channel with oppositely rotating multicylinder rotors. Experiments were carried out using water-glycerine solutions as a working fluid. The rotation resistance moment and its pulsations were investigated, using the system for measuring the torque resistance of rotation of rotors, made in the form of a digital dynamometer based on a tension sensor. The investigations made it possible to establish that the classic dependence of the appearance of Taylor vortices is observed in the slit flow of a multicylinder system rotating oppositely. It was shown that in the range of Reynolds numbers Re = (100 – 500), pulsations of dissipative processes with variable frequency and amplitude up to 10% of the mean value of rotation resistance are observed.
Experimental study of the transport properties of Nd-Fe-B and Sm-Co magnets
Authors: Samoshkin Dmitrii , Agazhanov Alibek
Published: January 2019

The article adduces new reliable experimental data on the thermal conductivity and the thermal diffusivity of hard magnetic materials of brands N35M, N35H, N35SH, as well as YX18, YX24 and YXG22, YXG30 with main components represented by the crystalline phases of Nd2Fe14B, SmCo5 and Sm2Co17 type, respectively. The temperature range from 293 to 773…1273 K has been investigated by laser flash technique with an error of 3—4%. The reference tables of the thermal diffusivity and thermal conductivity coefficients have been developed. The character of the thermal diffusivity changes near the Curie point has been determined. The critical indices and the critical amplitudes have been defined.
The influence of the viscosity on the oscillations of the element of magnetic fluid in the magnetic field
Authors: Ryapolov Petr , Polunin Vyacheslav , Alisher Gulamov , Shel’deshova Elena
Published: January 2019

The article describes a study of the viscoelastic parameters of the system based on a element of magnetic fluid bounded by the surface of a horizontal plexiglass tube located in the field of an electromagnet. A element of magnetic fluid makes damped oscillations. A mechanism is proposed for interpreting the experimental results to determine the dependence of the viscosity of a magnetic fluid on the magnetic field strength.
High heat flux flow boiling of refrigerant R236fa in parallel microchannels
Authors: Kuznetsov Vladimir , Shamirzaev Alisher , Mordovskoy Alexander
Published: January 2019

This paper presents the results of an experimental study of the heat transfer during flow boiling of refrigerant R236fa in a horizontal microchannel heat sink. The experiments were performed using closed loop that re-circulates coolant. Microchannel heat exchanger that contains two microchannels with 2x0.4 mm cross-section was used as the test section. The dependence of average heat flux on wall superheat and critical heat flux were measured in the range of mass fluxes from 600 to 1600 kg/m2s and in the range of heat fluxes from 5 to 120 W/cm2. For heat flux greater than 60 W/cm2, nucleate boiling suppression has significant effect on the flow boiling heat transfer, and this leads to decrease of the heat transfer coefficient with heat flux grows.
Towards knowledge interoperability between the UML, DMN, BPMN and CMMN models
Authors: Suchenia Anna , Kluza Krzysztof , Wiśniewski Piotr , Jobczyk Krystian , Ligęza Antoni
Published: January 2019

Development of modern software systems consists of many different phases, the sequence of whom is referred to as the software life cycle. During these phases, business analysts gather requirements from clients and try to design a system in order to fulfil these requirements. Software design of complex systems exploits various notations for representing knowledge about system structure and behaviour, decisions, processes and different cases. These elements are modelled using such graphical notations, maintained by Object Management Group (OMG), such as UML (Unified Modelling Language), DMN (Decision Model and Notation), BPMN (Business Process Model and Notation), and CMMN (Case Management Model and Notation). In this paper, we present our work-in-progress analysis of the current state of the art in knowledge interchange for these notations. Moreover, we identify the integration or interchange approaches in terms of application areas. Our goal is to provide an input for an integrated method of designing systems with the use of these notations.
Estimation of critical force of the buckling composite structures using modelling methods
Authors: Szklarek Karol , Gajewski Jakub , Valis David
Published: January 2019

The study reported in this paper employed Artificial Neural Networks (ANN) to predict the critical force of the buckling composite structures. The critical force depends upon various factors such as thickness, stacking sequence, etc. These factors have been identified in earlier studies by means of the Finite Elements Method (FEM). The critical force is affected by the above-mentioned factors. Various approaches have been applied in the course of the presented study. Apart from our FEM simulation, the ANN approach has been applied and the results were compared. The main contribution of these two approaches is the estimation of the critical force. The ANN model is trained to predict the critical force for different configurations of input variables.
Implementation of artificial intelligence in optimisation of technological processes
Authors: Lipski Jerzy , Zaleski Kazimierz
Published: January 2019

This article introduces an algorithm for determining optimal parameters of a technological process. The objective function is the processing time of operations (efficiency) at the constraint of quality requirements of finish according to the designer specification. The problem of selecting a correct combination of processing parameters may only be solved when the cause-and-effect relationship between the finish quality and the machining settings is known. If the process considered for optimisation is repeatable, it appears economically viable to invest resources in the development of a model that would describe these relationships. To this end, we propose employing the artificial neural network trained on the progressions obtained from the tests. In the second stage, the Multiple-Input-Multiple-Output (MIMO) system, capable of representing relationships of nonlinear nature, was implemented for the optimisation of the objective function. The paper presents the application of the developed algorithm in determination of optimal parameters for the roller burnishing process of surface treatment. A technologist/software user defines the range of acceptable surface finishes. The optimisation algorithm determines a set of modifiable parameters that ensure minimal processing time at a specified surface finish requirements constraint.
Comparative analysis of two-group supervised classification algorithms in the study of P300-based brain-computer interface
Authors: Plechawska-Wójcik Małgorzata , Kaczorowska Monika , Michalik Bernadetta
Published: January 2019

The main goal of the paper is to perform a comparative accuracy analysis of the two-group classification of EEG data collected during the P300-based brain-computer interface tests. The brain-computer interface is a technology that allows establishing communication between a human brain and external devices. BCIs may be applied in medicine to improve the life of disabled people and as well for entertainment. The P300 is an event-related potential (ERP) appearing about 300 ms after the occurrence of the stimulus of visual, auditory or sensory nature. It is based on the phenomenon observed in anticipation for a target event among non-target events. The 21-channel 201 Mitsar amplifier was used during the experiment to store EEG data from seven electrodes placed on the dedicated cap. The study was conducted on a group of five persons using P300 scenario available in OpenVibe software. The experiment was based on three steps the classifier learning process, comparison and averaging of the obtained result and the final test of the classifier. The comparative analysis was performed with the application of two supervised classification methods: Linear Discriminant Analysis (LDA) and Multi-layer Perceptron (MLP). The preliminary data analysis, extraction and feature selection was performed prior to the classification.
Mobile system for road sign detection and recognition with template matching
Authors: Maćkowski Michał , Sawiski Michał , Walczyszyn Wojciech
Published: January 2019

This paper explores the effective approach to road sign detection and recognition based on mobile devices. Detecting and recognising road signs is a challenging matter because of different shapes, complex background and irregular sign illumination. The main goal of the system is to assist drivers by warning them about the existence of road signs to increase safety during driving. In this paper, the system for detection and recognition of road signs was implemented and tested with the use of Open Source Computer Vision Library (OpenCV). The system consists of two parts. The first part is the detection stage, which is used to detect the signs from the whole image frame and includes the modules: data-image acquisition, image pre-processing and sign detection. During this stage, the impact of Canny edge detector and Hough transform parameters on the quality-level of sign detection was tested. The second part is the recognition stage, whose role is to match the detected object with a priori models of signs in the dataset. In the research, the authors also compared the influence of various image processing algorithms parameters to the time of road sign recognition. The discussion part answers also the question whether the mobile system (smartphone) is robust enough to detect and recognise road sings in real time.
Effect of technological parameters on vibration acceleration in milling and vibration prediction with artificial neural networks
Authors: Zagórski Ireneusz , Kulisz Monika
Published: January 2019

This paper reports on the study of vibration acceleration in milling and vibration prediction by means of artificial neural networks. The milling process, carried out on AZ91D magnesium alloy with a PCD milling cutter, was monitored to observe the extent to which the change of selected technological parameters (vc, fz, ap) affects vibration acceleration ax, ay and az. The experimental data have shown a significant impact of technological parameters on maximum and RMS vibration acceleration. The simulation works employed the artificial neural networks modelled with Statistica Neural Network software. Two types of neural networks were employed: MLP (Multi-Layered Perceptron) and RBF (Radial Basis Function).
Vibration identification of the roadheader cutting head using high-speed cameras
Authors: Cheluszka Piotr , Mann Rajmund
Published: January 2019

Vibrations of the roadheader cutting head were measured by means of two methods during the cutting performed on the test set-up created at the Faculty of Mining and Geology at the Silesian University of Technology. The first of them included installing accelerometers on the roadheader boom near the cutting heads. In the second one, a photogrammetric kit was used, major components of which were high-speed cameras connected with TEMA Motion 3D software used for movement analysis. Based on the motion recorded in videos, the cutting head movement trajectories were delineated, with their velocity and acceleration determined. This article presents a photogrammetric method, as well as selected results of the comparative analysis of cutting head vibrations using both methods when cutting simultaneously with two cutting heads, with the boom inclination perpendicular to the floor.
Design and Simulation of Small-Scale Horizontal-Axis Wind Turbine with Diffuser Effect
Authors: Czyż Zbigniew , Karpiński Paweł , Klepka Tomasz , Szkoda Zbigniew
Published: January 2019

The article presents the results of the investigation of a rotor assembly of a wind turbine with a horizontal axis of rotation. The rotor is equipped with a diffuser which is an integral part of the power generating unit. The research was carried out by means of the ANSYS Fluent software. The geometry used for the tests is a development version of the construction shown in patent application PL 412553 and is characterised by an adjustable angle setting of the rotor blades. The geometric model was obtained by 3D scanning of the actual rotor using the ZScaner scanner ®700. The calculations were carried out for the selected blade angle of attack from 0° to 90° separately for the version with and without the diffuser. The results from the conducted tests were used to determine the characteristics of the power generated by the turbine as a function of rotor speed. The secondary objective of the tests was to analyse the effect of the diffuser on the power generated by the entire rotor assembly.
Low Reynolds Number Rotor Blade Aerodynamic Analysis
Authors: Tulwin Tytus
Published: January 2019

Maintaining a steady hover flight in a rotorcraft usually requires high energy input. The aim of the paper is to prove that it is possible to vastly reduce energy use in a rotorcraft by reducing the disc loading. The energy consumption reduction is especially important in electric rotorcraft, where the energy source is characterized by low energy density when compared to the hydrocarbon fuel in ICE rotorcraft. The paper presents results of CFD simulations on low Reynolds Number operating rotors. For low RE rotors tip vortex induced drag is highly affecting the rotor’s Figure of Merit, thus reducing rotor performance. Even though FM is reduced, the low RE setup is still beneficial in terms of reduced Power Loading, the main factor responsible for hover endurance.
Simulation Research of Aircraft Piston Engine Rotax 912
Authors: Grabowski Łukasz , Siadkowska Ksenia , Skiba Krzysztof
Published: January 2019

This paper reports the results of simulation works of Rotax 912 aircraft piston engine, which is a basic unit in most ultra-light aircrafts. The method for preparing the model aircraft engine operation process was presented. Simulation tests were carried out in the AVL Boost programme. The programme allows a full use of zero-dimensional and one-dimensional modelling. It also allows a comparison of other engine models. The developed model has enabled us to simulate the flow of air through the inlet pipes, carburettors, valves and combustion process. The preparation of the model required us to enter parameters that are not available in the manufacturer's catalogue, therefore, necessary measurements and analysis of the engine parts were carried out on a laboratory bench. The calculations in the AVL Boost programme were carried out in the conditions determined for the selected BMEP values with the objective of characterising the engine performance by determining its power, torque and fuel consumption.
Numerical modelling of water percolation through mortar-based connection of concrete pipes
Authors: Widomski Marcin K. , Pawelec Iwona , Kumar Ajay , Łagód Grzegorz
Published: January 2019

This paper presents an attempt to numerical modelling of water seepage through the connection of two concrete pipes, commonly used in the past in construction of sanitary and stormwater sewerage systems, sealed by three types of different cement-based mortars. The 2D numerical calculations were made by means of the commercial modelling software FEFLOW, WASY-DHI, especially popular in soil and environmental science. The required input data for the developed numerical model, including saturated hydraulic conductivity and retention characteristics of tested mortars, were obtained during the conducted laboratory measurements. The hydraulic characteristics of the applied concrete pipe were based on literature. The assumed boundary conditions reflected the concrete sewerage pipe filled by water to the height of 10 cm and the matric suction pressure of soil below the sand bed. Our numerical calculations showed diversified seepage intensity and accumulated volume of percolating water for the three tested mortars. The observed differences were in our opinion related to sand/cement ratio of each mortar. The higher sand content, the higher volume of seepage was noted.
Simulation of the medical syringe injection moulding process
Authors: Białasz Sebastian , Klepka Tomasz
Published: January 2019

This paper contains a description of tests including the simulation of the injection moulding of thin-walled products. The simulation was designed to analyse the potential impact of processing conditions and cooling conditions on the defects of thin-walled products of the body of the syringe. In order to obtain the correct results, the analysis was based on a simulation comparison with the data obtained after the injection mouldings were produced. Four cases were considered - parameters with reduced injection pressure and absence of pressure push, with a reduced temperature of the injection mould. The test results were analysed in conditions compliant with the recommendations of the production card and with the parameters optimised by computational algorithms of the computer programme. Simulations were carried out using the Simcon CadMould 3D-F programme. The paper describes the construction of a thin-walled body, which is the main segment of a medical instrument - a medical syringe. Also described in the paper are the process of injection of polymer materials and the characteristics of the production of medical syringes. In addition the computer programme software for the simulation of production processes was presented.
Numerical analysis of heat exchange process in the biomass carbonisation reactor
Authors: Zarzycki Robert , Jędras Justyna
Published: January 2019

The study presents the problem of heat exchange in the biomass carbonisation reactor with cyclic operation. Based on the actual parameter of the biomass carbonisation reactor, a geometrical model was developed, and the computation of the heating process was conducted for two cases: an empty reactor and a filled reactor. Its result demonstrated that for the analysed configuration of the reactor, the process of heating biomass in the containers is limited by the capability of heat transfer to the biomass in the container. The results suggest opportunities for the improved heat exchange in the reactor and, accordingly, shortening heating time through installation of the system that forces circulation of hot air inside the reactor.
Performance analysis of mobile applications developed with different programming tools
Authors: Smołka Jakub , Matacz Bartłomiej , Łukasik Edyta , Skublewska-Paszkowska Maria
Published: January 2019

This study examines the efficiency of certain software tasks in applications developed using three frameworks for the Android system: Android SDK, Qt and AppInventor. The results obtained using the Android SDK provided the benchmark for comparison with other frameworks. Three test applications were implemented. Each of them had the same functionality. Performance in the following aspects was tested: sorting a list of items using recursion by means of the Quicksort algorithm, access time to a location from a GPS sensor, duration time for reading the entire list of phone contacts, saving large and small files, reading large and small files, image conversion to greyscale, playback time of a music file, including the preparation time. The results of the Android SDK are good. Unexpectedly, it is not the fastest tool, but the time for performing most operations can be considered satisfactory. The Qt framework is overall about 34% faster than the Android SDK. The worst in terms of overall performance is the AppInventor: it is, on average, over 626 times slower than Android SDK.
Technical aspects of SAW gas sensors application in environmental measurements
Authors: Guz Łukasz
Published: January 2019

The development of semiconductor technology and computer methods allows for the improvements in air pollutions measurement techniques. Besides the traditional techniques of air pollution measurement such as chromatography or dynamic olfactometry, the electronic nose (EN) gains increasing attention in this area. EN is a device which imitates the human olfactory sense. The main component of the device is an array of many nonspecific gas sensors. In this article, the most frequently used types of gas sensors in scientific studies were shortly characterised as: metal oxide semiconductors (MOS), conducting polymers, quartz microbalances (QCM) and surface acoustic wave (SAW) sensors, and others. Both their advantages and disadvantages were summarised. Technical aspects of measurements using SAW gas sensors arrays were presented, as well as measurement circuits were described.