bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complex electrical impedance and dielectric spectroscopy of Na+-conducting PEO/PVP/NaIO4 solid polymer electrolyte with incorporated nano-sized Graphene Oxide
Authors: Vlakhov T E , Marinov Y G , Hadjichristov G B , Scaramuzza N 
Published: February 2021

Abstract
Being of significant interest as electrolytic materials for mini-mobile energy storage devices, we have studied solid-state polymer-based electrolytic systems – nanocomposites, in particular, NaIO4 salt-complexed poly(ethylene oxide) (PEO)/polyvinyl pyrrolidone (PVP) polymer blends doped with nano-sized Graphene Oxide (GO). The GO monolayer average size and thickness were 5 μm and 2 nm, respectively. In the PEO/PVP polymer blend, the PEO:PVP ratio was 70:30 weight percent (wt.%), the concentration of the salt sodium metaperiodate NaIO4 was 10 wt.%. The nano-sized GO was dispersed with concentration of 0.2; 0.4 and 0.6 wt.%. Thin films (150 μm) of GO/PEO/PVP/NaIO4 Na+ ion-conducting nanocomposites were produced by solution casting technique. They were studied by complex electrical impedance and dielectric spectroscopy in the frequency range 0.1 Hz – 1 MHz of the applied electric field. The room-temperature ion conductivity, the complex dielectric function, dielectric loss and AC conductivity of GO/PEO/PVP/NaIO4 at various concentration of GO were obtained, and the effect from the GO nanofillers was estimated.
Single-photon generation of entangled triplet state in an atomic spin dimer
Authors: Varbev S , Boradjiev I , Chamati H 
Published: February 2021

Abstract
We show that the entanglement between two atomic spins, coupled via XY interaction, can be achieved with the aid of a single photon in a controllable manner. Assuming a constant spin-photon coupling, two distinct cases are considered — excitation with a constant and with a linear time-dependent photon frequency. We demonstrate that these problems reduce to the study of the well known Jaynes-Cummings and Jaynes-Cummings – Landau-Zener models, respectively, where the two-level system is formed by the zero-momentum mode states of the dimer. Owing to the exact solubility of both models, by tuning the relevant parameters, one can design and coherently control the dynamics of the excitation process. For instance, one can adiabatically switch from an atomic spin system initialized in a state with both spins down to the maximally entangled triplet state.
Infrared Optical Constants of Chromium Nano-films
Authors: Udachan S L , Ayachit N H , Udachan L A , Siddanna S , Kolkundi S S , Ramya S 
Published: February 2021

Abstract
In the present work, nanofilms of chromium have been prepared by thermal evaporation in vacuum on to ultrasonically cleaned glass substrates held at room temperature (22 °C). Films have been characterized by using X-ray diffraction (XRD) spectra, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Infra-Red (IR) spectra were used to examine the morphology and nano-structures to find out the cause. The transmission measurements were made on chromium films in the thickness range (6 – 60) nm for the incident photon energy of wavelength range, (2.5 - 4.5) μm. The optical transmittances of films have been found to decrease with increase in the film thickness in the entire IR spectral region of incident photon energy. In this case the optical constants like refractive index (n), absorption coefficient (a), extinction coefficient (k), real part (ε′) and imaginary part (ε″) of relative permittivity are obtained from IR spectrum.
Magnetic field effect in piezoelectric resonators with HTS electrodes
Authors: Nurgaliev T , Beshkova M 
Published: February 2021

Abstract
Microwave (MW) impedance of a square-shaped piezoelectric (PE) resonator containing an AlN film with tilted c – axis and high temperature superconducting (HTS) electrodes was modelled for the case of propagation of longitudinal and shear acoustic waves (AW) across the resonator thickness. External DC magnetic field B was assumed to be applied perpendicularly to the resonator surface. It was shown, that the magnetic field results in a decrease of the resonance frequency and an increase of the MW losses. The effect is due to a change of the MW impedance of HTS component under action of the magnetic field.
Solid particle radiator systems for heat rejection in space
Authors: Zhao C , Huang Y , Wang J 
Published: February 2021

Abstract
The radiator for the heat rejected in space proposes a new technological solution which utilizes a stream of solid particle to radiate waste heat. This paper presents the concept of Solid particle radiator (SPR) and highlights the distinctive characteristics of SPR and the Liquid droplet radiator (LDR). The design model of the solid particle radiator system was established and evaluated from the view point of reducing the rate of mass per unit power, avoiding the contamination due to the loss via evaporation and enhancing the efficiency of heat transfer. And the radiating temperature of this system could range to a large extent in the case of without considering evaporation loss. The mass model of system was presented here, and the evaluation parameters were used to analyze the performance of SPR in the different conditions. When compared with the performance of the liquid droplet radiator under the same condition of different mediums and Heat Pipe radiator, the SPR manifests the differences in the variations of thermal load, mission time and other design parameters of the system. Finally, this radiator exhibits the significant potential of substituting for the conventional radiator and the LDR in space according to the calculation results. Thus, the Solid particle radiator could be employed for a wide range of heat rejection applications in space.
The behavior to cavitation erosion of CuSn12-C bronze structures, as obtained by in-depth heat treatments
Authors: Lazar I , Bordeasu I , Mitelea I , Pirvulescu L D , Salcianu C L , Popoviciu M O 
Published: February 2021

Abstract
CuSn bronze alloys are some of the most used in the casting of freshwater ship propellers. Through in-depth heat treatments, the microstructure and hardness are substantially altered when compared with the initial state of the material after casting. The work highlights the change in the behavior and resistance to the vibrating cavitation erosion of the CuSn12-C bronze microstructures, after being subject to two in-depth heat treatments (hardening at 700ºC, followed by cooling in water, and two hardening treatments at 700ºC, with cooling in water, followed by tempering at 500ºC and 250ºC, with cooling in air). The experimental tests are performed using the vibrating standard piezoelectric crystal assembly, available in the Cavitation Research Laboratory at the Polytechnic University from Timisoara.
Elementary chemical analysis of different clay types
Authors: Aluvihara Suresh , Kalpage C S , Lemle K L 
Published: February 2021

Abstract
Clay is a useful raw material for most of industrial manufacturing processes because of the unique physico-chemical properties and chemical compositions of such clays. The analysis of chemical compositions of some clay is an important strategy that related with the usages of such clay for various industrial purposes. In the existing research there were expected to test and analyze the chemical compositions of three different clay types that available in various locations in Sri Lanka using the X-ray fluorescence (XRF) technique. The clay samples were collected carefully from the available locations and stored well. The clay samples were labeled as anthill clay, brick clay and roof tile clay based on the applications and origins of such clays. A sufficient portion from each clay sample was selected and those samples were oven dried for 24hours under the temperature 110°C and sent for the X-ray fluorescence (XRF) analysis. As the results for the investigations, there were observed the elements of Fe, Ti, Ba and K in the amounts of 82.08%, 4.84%, 0.79% and 12.28% from anthill clay, Fe, Ti, Ca and Ba in the percentages of 84.38%, 5.92%, 7.56% and 2.14% in brick clay and Fe, Ti, Ba, Zr and K in the percentages of 75.72%, 2.95%, 5.30%, 3.36% and 12.67% from roof tile clay.
Fundamental physico-chemical and mechanical analysis of different clay types
Authors: Aluvihara Suresh , Kalpage C S , Lemle L D 
Published: February 2021

Abstract
Clay plays an important role in the most of industries that related with water treatment and food stowage industries. The adequate physic-chemical properties are the most recognized factor for the wide range of applications. The investigation of the fundamental physic-chemical and some mechanical properties of such clay is an insistent task before the selection of some material for some specific role. The analysis of the fundamental physic-chemical and grain size analysis of grain sizes of three different types of selected clays were the aims and objectives of the existing research. Clay samples were collected from three different locations in Sri Lanka and they were stored well. The clay samples were named as anthill clay, brick clay and roof tile clay. Some potion from each clay sample was separated and such separated clay samples were oven dried for 24 hours under the temperature 110°C. Each of dried clay sample was separated again and the separated portions were prepared for the test of moisture content, dry sieve analysis and wet sieve analysis. As the major results of the experiment, especially there were obtained 14.49%, 21.45% and 25.97% moisture contents with respect to anthill, brick and roof tile clays, well-graded particle arrangement in roof tile clay, gap graded particle arrangement in anthill clay and uniformly graded particle arrangement in brick clays. In addition, according to the obtained results there were seen the finer particle weight percentages as 59.90%, 37.36% and 72.38% with respect to anthill clay, brick clay and roof tile clay.
Spatial-factorial analysis of background status of the Danube River basin state on the northeastern slops of the Ukrainian Carpathians
Authors: Kravchynskyi R L , Korchemlyuk M V , Khilchevskyi V K , Arkhypova L M , Mykhailiuk J D , Mykhailiuk I R 
Published: February 2021

Abstract
The study solved the problem of analyzing the background spatial-factorial patterns of distribution of quantitative and qualitative indicators of groundwater sources and surface waters within the upper part of the Prut River that belongs to the Danube River basin. The studies have been conducted within the Carpathian National Nature Park, located on the northeastern slopes of the Ukrainian Carpathians. The basic regularities and peculiarities of the distribution of springs in the researched territory have been studied by means of factor analysis of the set of estimation parameters and the relationships between them. Patterns of changes in the concentrations of the natural components of the qualitative composition of the hydro-ecosystem have been found, depending on the altitude of the terrain. Similar data has been obtained in the analysis of the relationship between the average geometric components of the chemical composition of natural waters and the length of the river. Trend lines and equations have been obtained, which can be used to determine the background normative values of natural water components along the length of the stream and the altitude of the basin for individual seasons and phases of water. In this paper, for the first time, the functional natural pattern of hydro-ecosystems of the upper part of the Danube basin within the northeastern slopes of the Ukrainian Carpathians is shown to increase its qualitative potential with increasing absolute altitude above sea level for nature conservation territory.
A method to detect cracks in the beams with imperfect boundary conditions
Authors: Lupu D , Gillich G R , Nedelcu D , Gillich N , Manescu T 
Published: February 2021

Abstract
Non-destructive testing of structures involving vibration-based damage detection methods implies knowing the beam’s boundary conditions. For perfect boundary conditions, numerous damage detection methods are developed and ensure more or less accurate estimation of the crack type, position, and severity. On the contrary, for imperfect boundary conditions, which are the real ones, there are only a few dedicated works. This paper presents a methodology that allows the identification of the weak clamping and the crack if both exist. The weak clamping is modelled as a defect that produces an identical relative frequency shift (RFS) for all vibration modes. Therefore, to find the two defects namely the real crack and defect simulating the weakly clamped end, we apply the principle of superposition. The method is implemented as an application written in the Python programming language. Tests show that defects are successfully identified even if there are uncertainties about the fixing of the beam.
Mining terrain curvatures approximation using the polynomials and a subsidence trough profile fragmentation
Authors: Orwat J 
Published: February 2021

Abstract
In an article a method of average course obtaining of measured mining terrain curvatures has been presented. Terrain curvatures values are very important for building objects located on mining areas and which have a considerable length or/and a great cubature. Curvatures observed graph has an irregular course and that’s why there is a need of their average course determination in order to obtain the most probable value. Measured curvatures approximation by use of the polynomial various orders has been done. Additionally, a whole profile of subsidence trough into the parts has been divided. Subsidence trough fragmentation allowed for a better fit of the curvatures average values to the observed values. A right polynomial order and a trough segments proper number taking into account value of variability coefficient of curvatures random dispersion have been chosen. Geodesic surveys, based on which a graph of measured curvatures has been obtained, in the Upper Silesian Coal Basin (Poland) have been done. There was conducted a mining exploitation of hard coal deposits by use of the longwall system with a roof rocks cave-in.
Investigation of the influence of the cutter-tool rake angle on the accuracy of the conical helix in the tapered thread machining
Authors: Onysko O , Panchuk V , Kopei V , Havryliv Y , Schuliar I 
Published: February 2021

Abstract
Tapered thread joints used in drill pipes largely determine the productivity of drilling processes and their environmental reliability. The quality of these joints depends on the values of the rake angle of the cutting insert of turning cutters used for making tapered threads. Modern manufacturers, because of the absents of algorithms for calculating the precision of the execution of the tapered thread spiral, depending on the size of the rake angle use the cutters only with a zero value of this angle. This greatly limits the possibility of producing drill pipes from high-strength materials, which is absolutely necessary in the modern drilling methods: obliquely directional and horizontal. The kinematic analysis presented in the article proves the difference between the theoretically specified spiral and their realized in the course of machine processing with cut tools with non-zero values of the rake angle. The deviation of the thread incline angle that is realized during turning is not regulated by standard requirement, as it is variable. The precision of the pitch of the tool-joint tapered thread is regulated by standard and must be ensured by the kinematics of the lathe. However, when screwing, the spiral screw lines of the pin and the box thread may not match, provided that they are made with using of tools with different values of the rake angle. Thus, it is lead to exceed the tolerances by one pitch. The algorithm allows to calculate the axial deviations of the screw line, depending on the value of the rake angle of the cutter for any of the points of the thread profile. It brings the fit of the cutters with a rake angle up to 5 ° to ensure the accuracy of the executed helices in the tapered thread machining.
The requirements for the design and construction of a gas cylinders aimed for transportation of a compressed and liquefied gases
Authors: Golubović-Bugarski V , Todić M , Petković S , Globočki-Lakić G 
Published: February 2021

Abstract
In this paper a typical requirements for the design and construction, workmanship and tests of a gas cylinders of water capacity between 150 l and 3000 l are described. This type of gas cylinder presents a refillable seamless steel tube aimed for transportation of compressed and liquefied gases exposed to extreme world-wide ambient temperatures. These tubes can be used alone or in batteries to equip trailers or multiple element gas containers (ISO modules or skids). When it comes about design requirements, the main focus is on the cylindrical shell thickness, which is calculated using the Lamé-von Mises formula. For some applications such as tubes assembled in batteries to equip trailers or skids (ISO modules) or MEGCs for the transportation and distribution of gases, it is important to calculate stresses associated with mounting the tube (bending stresses, torsional stresses, dynamic loadings etc.). Special attention must be paid to design of tube ends, which should be approximately hemispherical. To permit internal visual inspection of the tube, an adequate opening must be provided at the neck ends. The tubes are manufactured from seamless steel tubing, typically hot rolled, extended/extruded or forged. The ends of tube are hot formed using either forging or spinning methods. After manufacturing process, each tube must be inspected in terms of surface imperfections. Next, each tube must be ultrasonically examined for internal and external defects and laminar imperfections and to determine wall thickness. Batch tests for checking the quality of tubes includes mechanical testing, such as tensile and impact testing. Beside the batch tests, all tubes must be subjected to the following tests: a hydraulic proof pressure test or a volumetric expansion test, a hardness test, a visual inspection, a visual check of the stamp markings, a dimensional inspection and an ultrasonic non-destructive testing (NDT). At the end of this paper, the most commonly found manufacturing imperfections are pointed out.
Temperature-frequency converter made with astable multivibrator and thermistor
Authors: Popa I , Popa G N , Diniş C M , Iagăr A 
Published: February 2021

Abstract
The temperature can be measured electrically by several methods: with thermoresistive transducers, with thermocouple transducers, with thermistors, with the pn junctions of semiconductor devices, etc. Thermistors are electrical resistors made of metal oxides with semiconductor properties, which are small in size, have very small time constants and can measure temperatures locally, without disturbing the temperature range in the measured area. In order to conveniently transmit the temperature information (without errors) at a distance, the paper uses an astable multivibrator circuit RC type, in which the resistor is replaced with a thermistor with negative characteristic, whose resistance changes depending on the temperature in a range allowed by this type of oscillator. After several experiments, it was established that for a certain value of a capacitor, using a thermistor with a negative characteristic, the frequency of the oscillator (rectangular signal) changes quasi-linearly (in the range of tens of kHz). The measured temperature (tens of 0C) corresponds to the environment in which the thermistor is mounted. It was possible to determine the value of the astable multivibrator circuit capacity for which the temperature and frequency ranges in which the converter is considered to operate quasi-linearly were established. The signal obtained from the output of the astable multivibrator circuit is transmitted remotely to a digital port of a microcontroller development board with an LCD shield that displays the measured temperature. Also, it is present the flow chart of program implemented in microcontroller.
Elastic couplings design with bolts using iPart and iAssembly concepts
Authors: Zs Miklos I , Miklos C C , Alic C I 
Published: February 2021

Abstract
This paper presents the possibilities for designing an elastic coupling with bolts, using the concepts iPart and iAssembly. Concepts iPart and iAssembly are in the category of tools to increase the productivity of computer-aided design in Autodesk Inventor. When designing the elastic coupling with bolts, these tools are very useful and productive, because the components of the coupling and the assembly have the same geometric shape with different types of dimensions. Basically, iPart and iAssembly tools allow creation of libraries for components (flanges, bolts, etc.) and elastic coupling, geometrically modeled once, which extract their dimensions from pre-created value tables, depending on coupling size determined based on the transmitted torque. In this respect, it is necessary that the components and the assembly to be modeled parametrically, i.e. all the dimensional constraints applied to be defined by a clear parameter
Predicting the dynamics of the maximum and optimal profits of innovative enterprises
Authors: Ilyina E A , Saraev L A 
Published: February 2021

Abstract
This article proposes new economic and mathematical models of the dynamics of the development of industrial enterprises that introduce innovative technologies. The level of attraction of innovative technologies by the enterprise is set by dimensionless coefficients of innovations, which depend on time and affect the increase in output and decrease in costs. The influence of not only production costs, but also transaction costs on the size of the enterprise’s profit was investigated, the sources of which are the forced costs of searching and processing economic information, financing negotiation procedures, developing and concluding contracts with partners, organizing the protection of property rights, paying for the opportunistic behavior of employees and enterprise managers, etc. It is found, that transaction costs force to maximize not only the profit function of the enterprise, but also the target transaction utility function, which takes into account the redistribution of profits in the interests of the enterprise management and for the implementation of socially oriented programs. The size of the part of the profit spent in the interests of the enterprise management and for the implementation of socially oriented programs is set by dimensionless redistribution coefficients. It is shown, that in the presence of transaction costs, the enterprise, instead of the maximum value of profit, achieves a lower optimal value of profit.