bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppression of spectral diffusion by anti-Stokes excitation of quantum emitters in hexagonal boron nitride
Authors: Tran Toan Trong , Bradac Carlo , Solntsev Alexander S. , Toth Milos , Aharonovich Igor
Published: August 2019

Solid-state quantum emitters are garnering a lot of attention due to their role in scalable quantum photonics. A notable majority of these emitters, however, exhibit spectral diffusion due to local, fluctuating electromagnetic fields. In this work, we demonstrate efficient anti-Stokes (AS) excitation of quantum emitters in hexagonal boron nitride (hBN) and show that the process results in the suppression of a specific mechanism responsible for spectral diffusion of the emitters. We also demonstrate an all-optical gating scheme that exploits Stokes and anti-Stokes excitation to manipulate spectral diffusion so as to switch and lock the emission energy of the photon source. In this scheme, reversible spectral jumps are deliberately enabled by pumping the emitter with high energy (Stokes) excitation; AS excitation is then used to lock the system into a fixed state characterized by a fixed emission energy. Our results provide important insights into the photophysical properties of quantum emitters in hBN and introduce a strategy for controlling the emission wavelength of quantum emitters.
Information dynamics with confidence: Using reservoir computing to construct confidence intervals for information-dynamic measures
Authors: Darmon David , Cellucci Christopher J. , Rapp Paul E.
Published: August 2019

Information dynamics provides a broad set of measures for characterizing how a dynamical system stores, processes, and transmits information. While estimators for these measures are commonly used in applications, the statistical properties of these estimators for finite time series are not well understood. In particular, the precision of a given estimate is generally unknown. We develop confidence intervals for generic information-dynamic parameters using a bootstrap procedure. The bootstrap procedure uses an echo state network, a particular instance of a reservoir computer, as a simulator to generate bootstrap samples from a given time series. We perform a Monte Carlo analysis to investigate the performance of the bootstrap confidence intervals in terms of their coverage and expected lengths with two model systems and compare their performance to a simulator based on the random analog predictor. We find that our bootstrap procedure generates confidence intervals with nominal, or near nominal, coverage of the information-dynamic measures, with smaller expected length than the random analog predictor-based confidence intervals. Finally, we demonstrate the applicability of the confidence intervals for characterizing the information dynamics of a time series of sunspot counts.
Latticed mode: A new control strategy for wind field simulation in a multiple-fan wind tunnel
Authors: Wang Jia-Ying , Zeng Ming , Meng Qing-Hao
Published: August 2019

On the basis of the actively controlled multiple-fan wind tunnel we designed, this paper proposes a latticed mode–based control strategy for the fan array. The so-called latticed mode is the overall topology of the working fans. In order to investigate the simulation ability of the latticed mode, several latticed modes are designed to analyze the temporal and spatial properties of generated wind fields. Airflow data under different latticed modes are measured using nine two-dimensional anemometers, and then, statistical indicators of wind speed and wind direction, as well as the spatial uniformity and complexity of generated wind fields, are calculated to analyze the characteristics of wind records. The results indicate that the distribution of active fans in the latticed mode has significant influence on the statistical properties and spatial evolutions of wind speed and direction. Besides, the latticed modes can regulate the spatial uniformity and complexity of the wind fields. The latticed modes with a high clustering degree of active fans can generate wind fields with low spatial uniformity and high complexity. In addition to the fan voltage and the rotation angle of swivel plates, the proposed latticed mode provides more possibilities for wind field simulation.
Zero-insertion-loss optical shutter based on electrowetting-on-dielectric actuation of opaque ionic liquid microdroplets
Authors: Ribet F. , De Luca E. , Ottonello-Briano F. , Swillo M. , Roxhed N. , Stemme G.
Published: August 2019

This article reports a broad-band optical shutter based on microdroplet actuation with zero optical insertion loss in the open state. These features are achieved by electrowetting-on-dielectric (EWOD) actuation of opaque ionic liquid microdroplets. The negligible vapor pressure of ionic liquids allows the device to robustly operate in open air, unlike previously proposed EWOD-based systems in which the light crosses several attenuating and reflective layers, preventing broad-band operation and creating insertion losses > 14%. The presented device provides an attenuation of 78 dB in the closed state and a transmission of >99.99999% in the open state and can operate in the visible and mid-infrared wavelength range. Moreover, the switch can sustain larger incoming laser powers (5 mW continuous exposure or up to 3 h of continuous exposure at ∼100 mW) compared to the values reported for other state-of-the-art EWOD-based shutters. Additionally, the proposed device is compact, operates with low voltage (<25 V peak voltage), and features zero static power consumption.
Analytical prediction of electrowetting-induced jumping motion for droplets on hydrophobic substrates
Authors: Zhang Kaixuan , Li Zhen , Chen Shuo
Published: August 2019

Electric voltage applied in electrowetting can induce spreading of a liquid droplet on solid substrates and yield significant contact angle reduction, which has been widely used for manipulating individual droplets in microfluidics and lab-on-a-chip devices, and even for creating jumping motion of droplets. Here, we present a theoretical closed-form expression of lift-off velocity to predict electrowetting-induced jumping motion of a droplet on hydrophobic substrates. In particular, we consider a liquid droplet wetting on a hydrophobic surface with a voltage applied between the droplet and the substrate. By turning off the applied voltage, the energy stored in the droplet deformation by electrowetting releases and may be sufficient to overcome the energy barrier for detachment. Based on the energy conservation of the droplet-substrate system, we derive a closed-form formula to predict the droplet jumping velocity in terms of the Young contact angle, the Lippmann-Young contact angle, and the Ohnesorge number. The validity of the theoretical prediction is confirmed by comparing the predicted jumping velocities with both experimental observations and numerical simulations. The predictive formula indicates that the jumping motion can be enhanced by increasing the Young contact angle and decreasing the Lippmann-Young contact angle or the Ohnesorge number. Also, a phase diagram of droplet jumping motion is constructed based on this model, which provides insights on accurate control of the electrowetting-induced jumping motion of droplets on hydrophobic surfaces.
Experimental analysis of one-dimensional Faraday waves on a liquid layer subjected to horizontal vibrations
Authors: Khan Talha , Eslamian Morteza
Published: August 2019

In this paper, we experimentally show the synchronous (harmonic) nature of the primary surface waves formed on a layer of water (∼1 mm) pinned to a glass substrate and subjected to horizontal (lateral) vibrations. With well-controlled experiments, we attenuated cross-waves and studied the primary standing waves in a one-dimensional wave configuration, with a high precision mechanical vibrator, capable of generating a range of forcing frequencies (100–500 Hz) and amplitudes (1–5 µm). We demonstrate that the emergence of instability (in the form of standing waves) depends upon the forcing amplitude and frequency and the average thickness of the liquid layer. Experiments reveal that the surface remains stable for sufficiently thin and thick layers of the liquid, while instability appears for thicknesses in between the two mentioned lower and upper limits. We show and analyze that, for the average liquid thickness of h = 1.5 mm, asymmetric modes of oscillations appear on the liquid surface; however, with a change in the film thickness and length of the surface profile, symmetric modes may occur as well (h = 2 mm). The problem studied here, i.e., a liquid film with pinned contact lines subjected to horizontal vibrations, shows some of the characteristics of an infinitely extended lateral liquid film, a liquid layer in a container with walls, and a sessile droplet.
Geostrophic adjustment on the equatorial beta-plane revisited
Authors: Rostami M. , Zeitlin V.
Published: August 2019

The process of geostrophic adjustment of localized large-scale pressure anomalies in the standard adiabatic shallow-water model on the equatorial beta-plane is revisited, and it is shown that the standard scenario of generation of westward-moving Rossby and eastward-moving Kelvin waves, which underlies the classical Gill theory of tropical circulation due to a localized heating, is not unique. Depending on the strength and aspect ratio of the initial perturbation, the response to the initial perturbation in the western sector can be dominated by inertia-gravity waves. The adjustment in the diabatic moist-convective shallow water model can be totally different and produces, depending on parameters, either Gill-like response or eastward-moving coherent dipolar structures of the type of equatorial modons, which do not appear in the “dry” adjustment, or vortices traveling, respectively, northwest in the Northern and southwest in the Southern hemispheres.
Molecular beam epitaxy growth of antiferromagnetic Kagome metal FeSn
Authors: Inoue Hisashi , Han Minyong , Ye Linda , Suzuki Takehito , Checkelsky Joseph G.
Published: August 2019

FeSn is a room-temperature antiferromagnet expected to host Dirac fermions in its electronic structure. The interplay of the magnetic degree of freedom and the Dirac fermions makes FeSn an attractive platform for spintronics and electronic devices. While stabilization of thin film FeSn is needed for the development of such devices, there exist no previous reports of epitaxial growth of single crystalline FeSn. Here, we report the realization of epitaxial thin films of FeSn (001) grown by molecular beam epitaxy on single crystal SrTiO3 (111) substrates. By combining X-ray diffraction, electrical transport, and torque magnetometry measurements, we demonstrate the high quality of these films with the residual resistivity ratio ρxx(300K)/ρxx(2K)=24 and antiferromagnetic ordering at TN=353 K. These developments open a pathway to manipulate the Dirac fermions in FeSn by both magnetic interactions and the electronic field effect for use in antiferromagnetic spintronics devices.
Triangular silver nanoparticle U-bent fiber sensor based on localized surface plasmon resonance
Authors: Song Hang , Zhang Hongxin , Sun Zhuo , Ren Ziyang , Yang Xiaoyu , Wang Qi
Published: August 2019

Optical sensors with local surface plasmon resonance (LSPR) of noble metal (gold, silver, platinum) nanoparticles have received extensive attention due to their excellent detection performance. Here, we propose an LSPR fiber-optic sensor with a graphene oxide/triangular silver nanoparticle structure. Benefiting from the LSPR characteristics of the silver triangle nanoparticles, the use of triangular silver nanoparticles provides significant sensitivity enhancement. In order to highlight the enhancement of silver triangle nanoparticles, we chose the commonly used silver spherical nanoparticles as a comparison. We used the finite difference time domain method to model and calculate the local electric field and extinction efficiency for the two shapes of silver nanoparticles. The simulation results show that the local electric field intensity of triangular silver nanoparticles is 10 times that of spherical silver nanoparticles, and the extinction efficiency is 4 times that of spherical silver nanoparticles. In the experiment, a U-shaped LSPR fiber sensor with spherical and triangular silver nanoparticles was fabricated. The former has a refractive index sensitivity of 342.7 nm/RIU and the latter has a sensitivity of 1116.8 nm/RIU. Even if there is temperature interference during the detection process, the detection result will not produce a large error.
Turbulent structures of shock-wave diffraction over 90° convex corner
Authors: Soni V. , Chaudhuri A. , Brahmi N. , Hadjadj A.
Published: August 2019

The turbulent structures and long-time flow dynamics of shock diffraction over 90° convex corner associated with an incident shock Mach number Ms = 1.5 are investigated by large eddy simulation (LES). The average evolution of the core of the primary vortex is in agreement with the previous two dimensional studies. The Type-N wall shock structure is found to be in excellent agreement with the previous experimental data. The turbulent structures are well resolved and resemble those observed in the experimental findings. Subgrid scale dissipation and subgrid scale activity parameter are quantified to demonstrate the effectiveness of the LES. An analysis based on turbulent-nonturbulent interface reveals that locally incompressible regions exhibit the universal teardrop shape of the joint probability density function of the second and third invariants of the velocity gradient tensor. Stable focus stretching (SFS) structures dominate throughout the evolution in these regions. Stable node/saddle/saddle structures are found to be predominant at the early stage in locally compressed regions, and the flow structures evolve to more SFS structures at later stages. On the other hand, the locally expanded regions show a mostly unstable nature. From the turbulent kinetic energy, we found that the pressure dilatation remains important at the early stage, while turbulent diffusion becomes important at the later stage. Furthermore, the analysis of the resolved vorticity transport equation reveals that the stretching of vorticity due to compressibility and stretching of vorticity due to velocity gradients plays an important role compared to diffusion of vorticity due to viscosity as well as the baroclinic term.
Initiating Opioid Agonist Treatment for Opioid use Disorder Nationally in the Veterans Health Administration: Who Gets What?
Authors: Manhapra Ajay , Stefanovics Elina , Rosenheck Robert
Published: August 2019

Background

Despite substantial benefits associated with opioid agonist treatment (OAT) with buprenorphine and methadone for opioid use disorder (OUD), only a small proportion of patients with OUD initiate OAT. There is a lack of studies addressing the correlates of OAT initiation among patients with OUD.

Methods

Using Veterans Health Administration (VHA) national administrative data, we identified veterans with OUD who started OAT with either buprenorphine or methadone maintenance treatment (MMT) in fiscal year (FY) 2012 (first prescription of buprenorphine or first methadone clinic visit after the first 60 days of FY) and those who received no OAT that year. Multivariate logistic regression models including sociodemographic characteristics, diagnoses, and service and psychotropic drug use variables were used to identify independent predictors of OAT initiation.

Results

Greater age (10-year increments; odds ratio [OR]: 0.96, 95% confidence interval [CI]: 0.0.9–0.97) and black race (OR: 0.46, 95% CI: 0.38–0.55) were associated with lower odds of being started on buprenorphine compared with no OAT, but not with MMT initiation. Veterans with cocaine and anxiolytic-sedative hypnotic use disorders had higher odds of being started on both buprenorphine and methadone compared with no OAT. Receipt of any mental health inpatient treatment was associated with higher odds of being started on buprenorphine but not methadone. Overall, we were unable to identify a robust set of patient characteristics associated with initiation of OAT.

Conclusion

This study points out the stark reality that in the middle of an opioid crisis, we have very little insight into which patients with OUD initiate OAT.
On a definition of the SI second with a set of optical clock transitions
Authors: Lodewyck Jérôme
Published: August 2019

The current SI second based on the atomic hyperfine transition in the ground state of 133Cs is expected to be replaced by a new definition based on optical frequency standards, whose estimated uncertainty has now been established two orders of magnitude lower than the accuracy of the best Cs primary standards. However, such a redefinition of the second is hindered by the fact that many atomic species are potential contenders to become the new primary frequency standard. In this paper, we propose to resolve this issue by defining a composite frequency unit based on the weighted geometric mean of the individual frequencies of different atomic transitions. This unit has the property to be realisable with any single clock whose transition composes the unit, provided that at least a few frequency ratios are available, with an accuracy that marginally differs from the nominal clock uncertainty. We show that the unit can be updated as the performances of the contributing transitions evolve, without incurring a drift on the unit itself.
Analytical Review of the Reports Presented at the 14th International Conference on Films and Coatings (ICFC14)
Authors: Kuznetsov V G , Kostrin D K
Published: August 2019

In this preface main trends in the development of films and coatings technology presented at the 14th International Conference on Films and Coatings (ICFC14) that was held on 14–16 May 2019 in Saint Petersburg, Russia are discussed.
Effect of electrolyte composition on electrochemical formation and properties of ceramic-like coatings on aluminum alloys
Authors: Borisov A M , Krit B L , Lyudin V B , Peretyagin P Yu , Suminov I V , Apelfeld A V , Anikin K A , Kondratsky I O
Published: August 2019

The electrochemical formation of ceramic-like coatings on D16 aluminum alloy was carried out using microarc oxidation method in phosphate (1.5 g/L NaOH + 9 g/L Na2SiO3 + 3 g/L Na3PO4) and molybdate (5 g/L NaOH + 30 g/L Na2SiO3 + 5 g/L (NH4)6Mo7O24) electrolytes. White and black ceramic-like coatings with thickness of 200–300 microns were obtained in phosphate and molybdate electrolytes, respectively.
Investigation of structure formation in thin films by means of optical pyrometry
Authors: Dolmatov A V , Milyukova I V , Gulyaev P Yu
Published: August 2019

The paper presents an approach to the identification of structural and phase changes in high-speed processes of spraying coatings and high-temperature synthesis of three-dimensional products from metal and ceramics. A method for evaluating the spectral degree of blackness of materials by means of optical pyrometry is described. An experimental complex was developed to study the degree of blackness of the surface of molybdenum, tantalum and tungsten foils in the process of stationary heating by electric current. The results of complex experimental studies are presented, showing that a jump in emissivity makes it possible to detect a change in the aggregate state of matter (liquid - solid), phase transitions, exo- and endothermic reactions in thin films, and also to determine characteristic temperatures with an error of 0.1–1.5%.
Receiving thin films of active component on surface of glass-fiber catalysts by method of reactive magnetron sputtering
Authors: Elyshev A V , Udovichenko S Yu , Bobylev A N , Matigorov A V , Zagoruiko A N
Published: August 2019

The technology for high-performance glass-fiber catalysts (GFC) on the basis of reactive magnetron sputtering to produce a thin film based on transition metal oxides with high adhesion to the support and film homogeneity in composition has been developed. Catalysts are appointed for environmentally friendly disposal of liquid hydrocarbon wastes and sludge with a reduction in gas emissions with possible further processing.
Plasma-induced formation of hydrogen resistant oxide layers on zirconium surface
Authors: Evsin A E , Begrambekov L B , Kaplevsky A S , Kudashev I S , Gumarov A I , Kashapov N F , Luchkin A G , Vakhitov I R , Yanilkin I V , Tagirov L R
Published: August 2019

Features of plasma-induced formation of the surface oxide layers on zirconium alloy E110 (Zr–1%Nb) as well as hydrogen resistant properties of these layers are studied. It is shown that irradiation of the E110 sample with 1 keV ions of He + O2 plasma produces the oxide layer depleted by oxygen nearby the surface. The onset of the intensive hydrogen penetration into the ion-irradiated sample during the steam test (673 K, 0.1 MPa) appears to occur 1500 hours later than into the untreated one.
Producing and investigation of radiation-absorbent coatings based on conductive polymers
Authors: Gareev K G , Khmelnitskiy I K , Aivazyan V M , Golubkov V A , Ivanitsa M G , Kunitsyn A S , Lagosh A V , Mikhailova O N , Reinyuk A V , Testov D O , Testov I O , Testov O A
Published: August 2019

PANI and PEDOT:PSS films were produced on a dielectric substrate and characterized by optical and electron microscopy. The absorption coefficient of electromagnetic radiation in films is measured using a coplanar transmission line. The possibility of using conductive polymers (PANI and PEDOT:PSS) as the basis for conformal radiation-absorbent materials designed to protect bio- and technosphere objects is shown.
Peculiarities of deposition of thick coatings based on binary Co-W alloy
Authors: Gololobov G P , Suvorov D V , Tolstoguzov A B , Tarabrin D Yu , Slivkin E V , Serpova M A , Avramenko S A
Published: August 2019

The present paper has represented the results of the research of electrochemical deposition of coatings based on Co-W alloy from the citrate electrolyte. Possibility to obtain large (more than 40 μm) thicknesses without cracking has been demonstrated. Peculiarities of the surface relief structure change after increase of the coating thickness have been researched. Possibility to control a concentration of tungsten in the coating alloy within the range 14 at.% – 21 at.% has been shown. Dependence of the coating microhardness on the thickness has been represented.
The efficiency of diamond-like coatings for increased wear resistance of end mills at the machining aluminum alloys
Authors: Grigoriev S N , Volosova M A , Fedorov S V , Shein A A , Zykova M A , Kapustina N
Published: August 2019

The efficiency of diamond-like carbon (DLC) coatings deposited by CVD- and PVD-technologies to increase the wear resistance of tungsten carbide end mills for aluminum alloy processing was experimentally studied. A complex of metallophysics studies was carried out including SEM analysis of coating surface, microrelief, a ratio between sp3- and sp2-bonds, and the microhardness of coatings obtained by nanoindentation. The final stage of the research addresses the operational testing of end mills during processing of high-strength aluminum alloy AlZn5.5MgCu.
Prediction of the functional characteristics of plasma titanium aluminide coatings by computer simulation
Authors: Jordan V I , Blednov V A
Published: August 2019

The results of stochastic simulation (computer-aided design) of a layered structure formation and functional characteristics (porosity, roughness, adhesion) of metal coatings based on titanium aluminide powders (γ-phase TiAl) under conditions typical of atmospheric plasma spraying are given. Taking into account the stable formation of a metal splats and titanium aluminide coatings, as well as minimum porosity and maximum adhesive strength of coatings, the optimal plasma spraying mode has been obtained: the particle velocity U

p
= 250 m/s, the particle temperature T

p
≤ 2050 K, the particle diameter D

p
= (30 ± 10) μm.
Reproducibility of a heterophase structure emergence effect when changing the ignition temperature of SHS in a layered nanosized nonstoichiometric Ti-Al system
Authors: Jordan V I , Shmakov I A
Published: August 2019

The simulation results of SHS process in a package of alternating nanoscale layers of the crystal lattices of Ti and Al atoms for two systems with various numbers of atoms and nonstoichiometric ratios are given. For simulation the LAMMPS package supporting parallel computations and the interatomic interaction potential in the “embedded atom” model (EAM) have been used. For two systems with various numbers of atoms and nonstoichiometric ratios the sets of temperature and density profiles along the layers of the structure at successive instants of time (up to 16 ns) have been obtained. For a system with 453974 atoms and a nonstoichiometric ratio of 1.23 the heterostructure emergence with an alternation of intermetallic phases when changing the SHS “ignition” temperature has been reproduced.
The study of hydrogenated titanium coatings
Authors: Kazakovsky N T , Korolev V A , Malkov I L
Published: August 2019

The paper considers use of a titanium coating as a sorbent of hydrogen isotopes in targets for neutron generators. The results of microsection analyses of coatings applied by the method of magnetron deposition with the various initial temperatures of a substrate are presented.
Producing and investigation of PEDOT films as electrodes of ionic electroactive actuators
Authors: Khmelnitskiy I K , Aivazyan V M , Alekseev N I , Broyko A P , Golubkov V A , Testov D O , Lagosh A V , Kalyonov V E
Published: August 2019

Experimental samples of ionic electroactive actuators with poly(3,4-ethylenedioxythiophene) electrodes (PEDOT) have been developed and produced. Measurements of amplitudes of a displacement, frequency and power characteristics of produced actuators were carried out. The influence of the membrane solvent, as well as the influence of the EDOT polymerization time on the sample structure and the output characteristics of actuators, was determined.
The optical constants of the films MgBaF4 in the range of 1.3–16 micron
Authors: Kotlikov E N , Novikova Yu A
Published: August 2019

A BaF2 films, characterized by low refraction coefficient in the infrared region of the spectrum, are widely used in the production technology of optical structures. Their serious drawback is the low mechanical strength and moisture resistance. This paper presents the results of an experimental study of the optical properties of a new type of MgBaF4 films made from a vacuum-sintered mixture of MgF2 and BaF2 to a homogeneous composition.
Properties of the protective powder coating made on the basis of nickel and received by the cold spray method
Authors: Krivina L A , Tsareva I N , Tarasenko Yu P , Berdnik O B
Published: August 2019

The structure, porosity, microhardness, adhesion strength of gasdynamic powder coatings have been investigated. Patterns of the process of electrochemical breakdown and passivation of coatings have been studied during comparative tests in the seawater in accordance with time factors. It is established that the protective coating on the basis of nickel with increased thickness in combination with low apparent porosity and high adhesion strength provides reliable electrochemical protection of the electric contacts made of titanic VT3-1 alloy in the sea water.
Interaction of the metal plasma flows with surfaces of complex geometric shapes
Authors: Kuznetsov V G , Kostrin D K
Published: August 2019

The features of coating formation using vacuum-arc discharge plasma on the inner surface of a cylindrical cavity with transverse ribs in the form of a diaphragm are considered. The mathematical model is developed and expressions for calculation of thickness of coatings are received. The effect of the diaphragm on the thickness distribution and uniformity of the coating is shown. Compression areas directly in front of the barrier affecting the coating deposition rate were found.
Thermal regime of the cathode in a vacuum-arc discharge during coating deposition
Authors: Kuznetsov V G , Kostrin D K , Valuev V P
Published: August 2019

The questions of stabilizing the cathode temperature in a vacuum-arc discharge are discussed. A model and a method for calculating the temperature of the working surface of the cathode end, eroded under the action of cathode spots, are presented. Stabilization of the cathode temperature is carried out by changing the arc discharge current during the operation of the evaporator in accordance with the obtained regularity or design solutions.
The research of the features destruction of the of oxide coatings on aluminum alloy by using the method of acoustic emission
Authors: Li X , Bashkov O V , Bao F , Kim V A , Zhou C , Shakirova O G
Published: August 2019

The influence of oxidizing the aluminum product 6070 with different times of micron exposure on the registration of acoustic emission signals (AE) during mechanical testing of samples was investigated. The results of microstructural studies after mechanical tests confirm the mechanism for generating AE signals associated with the destruction of coatings and the effects of plastic deformation on microarc oxidation, the newly formed surfaces of the substrates.
Improve wear resistance of composite coatings on cutting tool from high-speed steel
Authors: Migranov M Sh , Shekhtman S R , Migranov A M
Published: August 2019

Some ways of improving the tribotechnical characteristics of wear-resistant coatings from high-speed steel on cutting tools after ionic surface modification are considered. The above studies show that the formed coating significantly increases (by 2.1–2.4 times) the wear resistance of the cutting tool due to the expansion of the stage of normal wear.
The currentless synthesis of tantalum and niobium carbide coatings on the carbon fibers and their electrocatalytic activity for the hydrogen peroxide decomposition reaction
Authors: Miklashov D G , Dolmatov V S , Kuznetsov S A
Published: August 2019

Coatings of tantalum and niobium carbides on the carbon fibers Carbopon-B-22 were obtained by the currentless transfer in the molten salts. The kinetics of the electrocatalytic reaction of the hydrogen peroxide decomposition on the surface of TaC/C and NbC/C composite materials was studied. The order of reactions was established, the rate constants were determined, and the activation energies of the hydrogen peroxide decomposition were calculated. It was established that the electrocatalytic activity of the NbC/C composition is higher than TaC/C.
Estimation of the cohesive strength of coatings made of powder materials
Authors: Moskvitin G V , Pugachev M S , Polyakov A N , Naumov O V
Published: August 2019

Methods for determining the mechanical properties of gas-dynamic coatings in shear (cut) and tensile tests are proposed to estimate the adhesive and/or cohesive strength of coatings more than 50 MPa. The results of studies on the strength of gas-dynamic coatings of copper, aluminum, zinc and nickel are presented. Dependences of mechanical properties of gas-dynamic coatings on the main technological modes of application are determined.
Effect of the plasma-forming gas consumption on processes of plasma spray coating and metal powder production
Authors: Okulov R A , Sarsadskikh K I , Ilinykh S A , Zakharov M N
Published: August 2019

The influence of the plasma-forming gas consumption on the plasma flow velocity and its turbulence intensity is analyzed. Full-scale experiment conducted to confirm the results of the mathematical experiment. Comparative analysis of the results of practical and theoretical experiments showed satisfactory convergence. As a result of the study, developers and consumers of equipment are offered recommendations for improving the technology.
Structural features and nitrogen positions in titanium oxynitride films grown in plasma of magnetron discharge
Authors: Pichugin V F , Pustovalova A A , Evdokimov K E , Konishchev M E , Kuzmin O S , Boytsova E L , Beshchasna Nataliia , Ficai Anton , Aubakirova D M , Sun Zhilei
Published: August 2019

The paper addresses the results of the analysis of the structural features of nitrogen-containing titanium oxides films, deposited by reactive magnetron sputtering. The films have a nanocrystalline two-phase structure and consist of anatase and rutile crystallites, regardless of the coating deposition regimes. No traces of titanium nitride phase are found in the film and nitrogen atoms in oxide form are localized at the grain boundaries of the deposited film.
Structure and properties of thin PZT films with inhomogeneous composition distribution
Authors: Pronin V P , Dolgintsev D M , Volpyas V A , Staritsyn M V , Kaptelov E Yu , Senkevich S V , Pronin I P
Published: August 2019

The paper presents the results of studies of bilayer thin ferroelectric PZT films with a lead content variation on the films thickness, formed by the method of radio-frequency magnetron deposition at different pressures of the gas mixture. It was shown that, depending on the sequence of deposition of the layers, both the structure and the dielectric parameters of the samples change.
Investigation of copper-doped aluminum composites with ceramic-like oxide coatings corrosion resistance
Authors: Savushkina S V , Agureev L E , Panasova G V , Apelfeld A V , Gerasimov M V , Sherbakov A I , Bogdashkina N L , Ignatenko V E
Published: August 2019

The effect of MAO coatings on the electrochemical behavior of aluminum composites without additives and doped with copper (1, 2, 3 wt%) in 3% NaCl solution compared to uncoated aluminum composites has been studied. A comparison of the polarization dependences of the current density lgi on the potential E of coated and uncoated aluminum composites showed the positive effect of MAO coatings on the electrochemical properties. It is shown that the presence of copper affects the electrochemical characteristics of composites with MAO coatings as compared to composites without additives. The values of current densities on the anode curves of MAO-coated aluminum composites with 1, 2, and 3% copper are not significantly different. On the local areas of the coatings the oxide-chloride compound islands were found after electrochemical tests.
Formation and properties of micro-arc silicate biocoatings on bioresorbable alloy Mg0.8Ca
Authors: Sedelnikova M B , Ugodchikova A V , Komarova E G , Tolkacheva T V , Sharkeev Yu P
Published: August 2019

The purpose of this study was to form the silicate biocoatings on Mg0.8Ca alloy by the micro-arc oxidation method and to study their structure, elemental and phase composition. With increase in the applied voltage from 350 to 500 V the biocoating thickness grew from 40 to 150 μm. Elongated crystals, which typical for wollastonite, were observed on the coating surface. EDX analysis revealed that the calcium and silicon are localized in the areas with elongated crystals. The wollastonite and akermanite crystalline phases were found in the coatings by XRD studies. Akermanite was formed because of wollastonite interaction with a magnesium substrate during the MAO process. When an applied voltage increased, an amount of akermanite reduced.
Reactive magnetron sputtering of hot titanium target in mixture of argon and nitrogen
Authors: Shapovalov V I , Minzhulina E A , Shestakov D S , Kochin A V
Published: August 2019

The influence of nitrogen flow rate on the discharge I-V characteristics of a dc magnetron with a single hot titanium target is studied. The basic processes forming the discharge are determined. The discharge physical models are proposed.
An affordable way to get silver nanoparticles for conductive inks and pastes
Authors: Sleptsov V V , Savkin A V , Kukuskin D Yu , Diteleva A O , Fursik A Yu
Published: August 2019

In this paper, we study the process of obtaining silver nanoparticles by the method of electrospark erosion of silver electrodes in distilled water with a significant overvoltage of the electrode gap. Studies were conducted on the previously developed experimental setup. The results showed that when the air discharge gap FV1 is much larger than the working discharge gap FV2, their exact ratios do not affect the particle size of the nanopowder. The particle size of the nanopowder is determined by other, not yet established process factors. Manufactured nanopowders have the same average size for all production modes and are characterized by a small scatter of particle sizes. The development of the process of obtaining silver nanoparticles by the method of electrospark erosion will reduce the cost of conductive inks and pastes in the future.
Technology of preparation of the LiCoO2 reactive mass for chemical current sources
Authors: Sleptsov V V , Govorov V A , Korobeynikov E V , Kovalev I A , Melnikov A B
Published: August 2019

The article discusses methods for the preparation of chemically reactive mass LiCoO2 in the form of dispersion for use in chemical current sources. The dispersion technique and the method of deposition of LiCoO2 particles from the obtained dispersion on the electrode material are described. The results of SEM on the penetration of LiCoO2 into the material and the results of mass changes are presented.
The functional relationship of tribological and anti-icing properties of multifunctional ultrathin fluoropolymer coatings
Authors: Vokhidov A S
Published: August 2019

The paper discusses the relationship between the physicochemical properties of film-forming polymer fluorine compounds, which form the so-called Langmuir-Blodgett structures on a treated surface in the form of ultrathin coatings and nanosize films, giving the treated surface tribological, anti-icing, and hydrophobic properties.
Etching by a beam of fast argon atoms of gas dynamic grooves on the surface of ceramic substrates
Authors: Volosova M , Melnik Yu , Metel A
Published: August 2019

A method of manufacturing the grooves of the end seals from high-strength dielectric materials is proposed. Uneven depth (no more than 10%) imposes a limit on the processing time. Grooves with a depth of ∼5 μm in corundum substrates can be made using a source of fast argon atoms in ∼1 hour with their energy of 3 keV and equivalent beam current of 1 A.
Research of adhesion of a covering on cylindrical surfaces
Authors: Yakupov N M , Yakupov S N , Gubaydullin R I
Published: August 2019

The approaches have been assessment of adhesion of a thin layer covering the surface of a cylindrical cover have been developed. An example of determination of adhesion from internal pressure and also an example of a research of adhesion have been considered at a cover bend. The method is a reliable tool for adhesive definition.
Affinity-dependent bound on the spectrum of stochastic matrices
Authors: Uhl Matthias , Seifert Udo
Published: August 2019

Affinity has proven to be a useful tool for quantifying the non-equilibrium character of time continuous Markov processes since it serves as a measure for the breaking of time reversal symmetry. It has recently been conjectured that the number of coherent oscillations, which is given by the ratio of imaginary and real part of the first non-trivial eigenvalue of the corresponding master matrix, is constrained by the maximum cycle affinity present in the network. In this paper, we conjecture a bound on the whole spectrum of these master matrices that constrains all eigenvalues in a fashion similar to the well known Perron–Frobenius theorem that is valid for any stochastic matrix. As in other studies that are based on affinity-dependent bounds, the limiting process that saturates the bound is given by the asymmetric random walk. For unicyclic networks, we prove that it is not possible to violate the bound by small perturbation of the asymmetric random walk and provide numerical evidence for its validity in randomly generated networks. The results are extended to multicyclic networks, backed up by numerical evidence provided by networks with randomly constructed topology and transition rates.
Analysis Of Flood Hazard Zones Using Overlay Method With Figused-Based Scoring Based On Geographic Information Systems: Case Study In Parepare City South Sulawesi Province
Authors: Adlyansah A L , Husain L R , Pachri H
Published: August 2019

Flooding is one of the serious problems that befell Parepare City, South Sulawesi Province. This problem has a negative impact on the surrounding community. Proper planning needs to be pursued so that losses from the disaster can be reduced. This study uses an overlay method with scoring between existing parameters, where each parameter is carried out a scoring process by giving the weight and value according to each classification which is then overlaid using ArcGIS 10.3 software. The use of this software utilizes a Geographic Information System (GIS) that can explain and present objects of flood hazard areas in digital form. The parameters which is used in this study are based on Kazakis et al. (2015), namely FIGUSED (Flow Accumulation, Rainfall Intensity, Land Use, Slope, Elevation, Distance to Drainage Network). The results obtained in the form of flood-prone maps where very vulnerable locations have an area of 10.72 Km2 or about 13.04% of the total area of the City of Parepare and the flood index value (FHI) 4.20 - 6.87 including high-hazard zones, have wide 48.04 Km2 or about 58.41% of the total area of Parepare City and the flood index value (FHI) 3.58 - 4.20 including the low hazard zone, and which has an area of 23.49 Km2 or about 28.55% of the total the area of Parepare City and the flood index value (FHI) 2.20 - 3.58 are included in the safe zone. Meanwhile, the causes of flooding in Parepare City are flow accumulation, slope, distance from the river, and landuse.
Modeling of Climate Change Impact on Water Availability in Metropolitan Mamminasata, Indonesia
Authors: Barkey R A , Soma A S , Nursaputra M , Mappeasse M F
Published: August 2019

Metropolitan Mamminasata is a National Strategic Area in South Sulawesi Province, Indonesia enacted based on Presidential Regulation Number 55 of 2011 on the spatial plan of Makassar, Maros, Sungguminasa, and Takalar urban areas. The development of these areas as central urban areas makes these areas are very prone to issues of water resilient. Eleven watersheds are affecting the water system in these areas: Jeneberang, Tallo, Maros, Bonelengga, Tabaringan, Lepa-Lepa, Paleko, Saro, Galesong, Pamukkulu, and Cikoang watersheds. The impact of climate change coincides with the change of land use affecting the availability of water in the area. Therefore, this study was conducted to find out the impact of climate change and land use on the availability of water at watersheds affecting the Metropolitan Mamminasata areas. The analysis was done by using Soil model and Water Assessment Tools (SWAT software). The data on climate was analyzed by using data on global weather climate of the 1987-1996 period (past condition) and 2004-2013 period (actual condition) and climate change projection of the 2035s period using RCP 4.5 Model CSIRO Mk3.6.0. Moreover, the data on land use analyzed was of 1996 and 2015. The results of the study indicate that land use in the study area had changed a lot from 1996 to 2015. This change decreased total forest area in watersheds in Metropolitan Mamminasata around 2,000 hectares (42,803.02 ha become 40,815.85 ha) and improved established areas such as settlement, agriculture, mining, and paddy field to 84,79% of the total watershed areas. The change of land cover has an interesting interaction with the climate change condition especially related to the availability of water in the study area. The SWAT model results explain the availability of water in 1987-1996 period as much as 1,682.55 million m3/year and in the 2004-2013 period decreased as much as 11.2% that is 1,485.30 million m3/year. The results of future water availability in the period of 2035s projected total potential water increased, but the potential increased in the wet month and decreased significantly in dry months, comparing to the actual condition of availability of water. This condition illustrates the change of land use, and climate contributes to the level of the quantity of water availability in several watersheds in Metropolitan Mamminasata. The planning of land use in the spatial plan is necessary to be applied so that the continuity of water availability is sustained every year to satisfy the need for water to fellow the increasing number of community.
Evaluating Nature Tourism Destination Potentiality in Samosir Regency using Remote Sensing and GIS
Authors: Susanti R , Ramadhani Y H , Harimurti M
Published: August 2019

Samosir regency is one of the national tourism destinations that has many tourist attractions for both domestic and foreign tourists. The management of sustainable tourism destination requires inventory of tourism assets. Inventory of tourism assets can be determined through natural resources condition in tourism area. Land cover monitoring become useful information to determine natural resources condition in tourism area. Remote sensing technology can be used to monitor land cover changes quickly, accurately and effectively. This research uses a method of digital land cover classification with object-based image analysis (OBIA) approach, because this method effectively used in high resolution image with true colour (RGB). The overall accuracy value obtained from land cover classification using the OBIA approach is 75,4 %. This study aims to analyze the potential of tourist attractions using land cover data as the determinants of physical characteristics besides tourist attractions in addition to attractions accessibility and facilities. Determination of tourism potential is obtained by looking at the relationship between the tourism site physical characteristics with the attraction of a tourist object then categorized using the scoring method. the result of multiple regression analysis obtained by correlation coefficient is R = 0,832, which means there is relationship between facility variable, land cover, and accessibility to the number of visitors in Samosir regency. Tourist attraction potential of Samosir regency is divided into three that is high, middle and low potential tourist attraction. The level of potential tourism object categories is expected to be used in the development of tourism planning in Samosir District to become a sustainable tourism destination.
Specification of Map Generalization from Large Scale to Small Scale Based on Existing Data
Authors: Susetyo D B , Hidayat F
Published: August 2019

Nowadays, the up-to-date and consistent digital spatial information is highly expected by the users. The kind of mapping method development which offers the potential to meet the high expectations is automatic map generalization. In Indonesia map generalization was only implemented in medium and small scale, and has never been done from large scale. This research aims as a beginning in map generalization from large scale by looking at the condition of existing data at all three levels of scale. Therefore, the data selected must be available on large, medium, and small scale. In this study, Bogor is chosen because it had been mapped on a scale of 1:5,000; 1:25,000; and 1:250,000. These operations used are a) selection, b) classification, c) amalgamation, d) aggregation, and e) simplification. The feature studied in this research is building. From this research, we can determine generalization pattern from scale of 1:5,000 to scale of 1:25,000 and 1:250,000 for building feature, so it can be used as prototype design in building generalization from large scale to medium and small scale.