RESONATORBASED FILTERS WITH FREQUENCY MODES CLOSE TO METAMATERIAL CELLS / Ilchenko M.E., Zhivkov A.P., Orlov A.T. K. Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. Many of the properties of metamaterials are similar to those found in the filter on mutually detuned frequency and unrelated resonators. The bridge filters are used as a lowfrequency prototypes of such microwave filters. It is important to establish an analogy between metamaterials and filters on mutually detuned frequency and unrelated resonators for further development and design of new types of metamaterials.
Objective. A central objective is a model development of metamaterials based on bandexclusive microwave filters on mutually detuned resonators, and the lowfrequencybased prototypes.
Methods. Characteristic equivalence test of metamaterials to microwave filters on mutually detuned resonators, their specific dependencies reveal (the modes in parallel channels, the locations of the attenuation poles above or below the bandwidth), manifested regardless of the types of resonators, the study of the possibility of the bridge filter prototypes using for metamaterials simulation.
Results. The analogy between metamaterials and microwave filters on mutually detuned resonator is specified, the possibility of bridge bandpass filter use as lowfrequency prototypes is shown.
Conclusions. Microwave filters on mutually detuned resonators, and bridge bandpass filters as lowfrequency prototypes, design techniques of which are well established, can be used for metamaterial modeling.
Keywords: metamaterials; dielectric resonators; stripline resonators; bandexclusive microwave filters.
Normalization of 2D Images “in Terms of Level” Based on Cosine and Hadamard Transform /Rybin O.I., Litvintsev S.M., Sushko I.O. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. The problem of pattern recognition is considered in this paper. We propose to use orthogonal basis functions for pattern recognition of 2D signals.
Objective. The aim of this paper is investigation of pattern recognition problem of 2D images based on cosine and Hadamard transforms.
Methods. Preprocessing of signals is proposed to reduce the number of spectral components in the orthogonal series of signal decomposition. Normalization of a reference signal “in terms of level” allows comparing reference and tested signals by means of transform coefficient calculation. This coefficient is a match criterion of these signals.
Results. Theoretical information used for proposed classification method is described. The normalization algorithms of the reference and tested signals, which have to perform before determining similarity of images, are proposed. Transformation of a reference signal to twodimensional basic function is fundamental point. This basic function is based on selected 2D orthogonal transform. Complete cycle of calculation for pattern recognition of some 2D images is executed. The calculations were performed using Hadamard and cosine transforms. 2D images of obtained spectra are given.
Conclusions. As a result, this research shows that we can perform pattern recognition of normalized 2D images based on calculation of transform coefficient. The analysis of calculation results shows that classification of signals based on transform coefficient values is possible. Development of matching classifiers is the aim of the next research.
Keywords: normalization in terms of level; image classification; Hadamard transform; cosine transform; pattern recognition.
Processes of Radiation Heat and Evaporation of Droplets and Their Influence on the Shielding Properties of Fire Water Curtains /Vynogradov A.G., Jakhno O.M. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. Water curtains are one of effective means of protection against fire thermal radiation. The analysis of the water curtain shielding properties is carried out by means of mathematical model operation. But the process of droplets evaporation as a result of their heating by fire thermal radiation is not considered in the existing mathematical model.
Objective. A central objective of the study is the analysis of processes of droplets radiant heating and evaporation, and also their influence on the water curtain shielding properties.
Methods. Thermodynamic analysis of the specified processes is made on the basis of the corresponding heat balance equations both for water curtain in general, and for separate droplets.
Results. Main results of the study are the numerical calculations and the graphic dependences of the parameters characterizing droplets evaporation for the typical regimes of thermal shielding. For the purpose of verification of the received results their comparison with results of earlier executed experimental studies on evaporation of water droplets at impact of laser radiation of infrared range was executed. It is established that theoretical results in limits of errors are in consent with the experimental results.
Conclusions. The conclusion follows from the received results that evaporation of droplets owing to their heating by a fire thermal radiation has no essential impact on the shielding properties of water curtains. This process can be not considered when performing technical calculations.
Keywords: fire water curtain; thermal radiation shielding; evaporation of droplets.
Impact Assessment of Demand Change of Consumers for Electric Power for Unevenness of Daily Graphs of the Energy System Load /Nakhodov V.F., Zamulko A.I., Mohammad Al Sharari, Medintseva D.A. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. The article is devoted to consideration of ways to assess the impact of consumer demand on electric power to the uneven load of the power system.
Objective. The main objective is the justification of the method choice to solve this problem, obtaining the most objective and meaningful assessment of the nature and extent of influence of groups of electrical consumers on configuration of daily graphs of the energy system load.
Methods. The methods of mathematical statistics, correlation and analysis of variance are used.
Results. The known methods of assessing the impact of consumer demand on power on the unevenness of the electric load of the power system are analyzed. A method for the determination of the coefficients of the influence of consumer groups is proposed, which allows us to objectively assess individual character and the degree of influence of these power groups for the nonuniformity of daily graphs of the power system load.
Conclusions. The utilization of the proposed method for the determination of the consumer influence coefficients on the configuration of the power system load graphs, will allow us to solve the problem of boundaries determination and daily tariff zone duration more reasonable, as well as the establishment of the necessary level of interest rates differentiated by the time electricity tariffs.
Keywords: graphs of the electrical load; irregularity of daily graphs; groups of consumers; consumers’ performance influence on the uneven load.
Analysis of Parallel Computations Efficiency for User’s Private Multimedia Data Protection in Clouds /Dychka I.A., Shyrochyn S.S., Sulema Ye.S. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. A significant part of data stored in cloud storages is multimedia data. The procedure of data protection can be organized as a trusted cloud service. Since this service is an intermediate layer between user layer and cloud storage the time of data processing in it is a critical matter. To achieve decreasing of time required for data protection procedure, parallel computations can be employed.
Objective. The objective of the research is to evaluate and analyze the time efficiency of parallel computations fulfilling in multimedia data protection procedures.
Methods. The comparative analysis results for three methods, namely: data fragmentation method, complementary image method, and LSBbased method with AES encryption, are presented in the paper. The methods are considered in terms of data processing time efficiency. The impact of both stegobits used for data embedding and data parallel processing threads is analyzed. The comparison is carried out for two types of multimedia data – audio data and graphical data.
Results. The time efficiency characteristics obtained and analyzed in the research show that the use of parallel computations in the Complementary Image method enables the decreasing of data processing time up to 70%.
Conclusions. The presented results enable comparing the considered methods in terms of their realization as software tool that is, along with data protection level, important characteristic for cloud services user. The Complementary Image method with parallel data processing can be effectively used for multimedia data protection.
Keywords: multimedia data protection; steganography.
Methodology of the Extreme Value Theory Application for Data Analysis /Zgurovsky M.Z., Trukhan S.V., Bidyuk P.I. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. To solve the problems of modeling and forecasting on the basis of large datasets (including singular ones) in conditions of uncertainty it is necessary to develop integrated information decision support systems (DSS). A methodology is proposed for application of extreme value theory for statistical models development and DSS on their basis.
Objective. The goal of the study is in application of the extreme value theory for analysis and estimation of model parameters on the basis of random samples. It is necessary to develop an effective methodology for analysis of pseudorandom sequences and estimation of unknown model parameters; to present examples of analysis using extreme value theory and software developed.
Methods. To solve the problems stated the following approaches were used: pseudorandom sequences generating procedures; probabilistic distributions of the extreme value theory, and methods for estimating unknown model parameters. A multistep methodology is proposed for extreme values processing and DSS is developed for analysis and modeling of pseudorandom sequences.
Results. Using the DSS developed and generated statistical data as well as proposed methodology the procedure was developed for extreme values analysis. The procedure is to be used for estimating of forecasting models for the process of various origin. A comparative analysis of parameter characteristics for GEVdistributions was performed.
Conclusions. Using the instrumentation developed it was shown that the proposed methodology for processing extreme values is convenient for analysis of singular datasets. This is substantiated with the high quality approximation of theoretical probability density by empirical curve. A comparison of model parameters estimation results showed that the estimates converge faster when parameters of form and scale are defined more exactly.
Keywords: extreme value theory; maximum likelihood estimator; simulation and modeling; decision support system.
Fast Kemeny Consensus by Searching over Standard Matrices Distanced to the Averaged Expert Ranking by Minimal Difference /Romanuke V.V. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. The problem of ranking a finite set of objects is considered.
Objective. The goal is to develop an algorithm that would let speed up the search of the Kemeny consensus along with substantiation of a metric to compare rankings.
Methods. An approach for aggregating experts’ rankings is suggested and substantiated. Also a metric to compare rankings is suggested and substantiated.
Results. The developed algorithm finds a set of Kemeny rankings much faster than the classical straightforward search. Also this set often contains a single Kemeny consensus, what fails by the straightforward search. Besides, a single Kemeny consensus is determined at one stroke if the averaged expert ranking turns out acyclic. Thus the problem of selecting a single Kemeny consensus is solved.
Conclusions. For 10 objects and more, where most known approaches become intractable, the algorithm still is tractable due to searching over only those standard matrices whose distance to the first ranking differs minimally from the distance between this ranking and the averaged expert ranking.
Keywords: ranking; Kemeny consensus; averaged expert ranking.
LowTemperature Formation of the FePt Phase in the Presence of an Intermediate Au Layer in Pt/Au/Fe Thin Films /Vladymyrskyi I.A. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. Pt/Fe bilayers with L10FePt phase are prospective candidates for applications in ultrahigh density magnetic storage due to their strong magnetocrystalline anisotropy. Typically, the L10FePt phase can be formed from the disordered A1 FePt phase after postannealing or after epitaxial growth on suitable substrates at elevated temperatures. However, industrial application of these films requires lowtemperature ordering as well as control of grain size and crystal orientation.
Objective. Investigation of the intermediate Au layer influence on the lowtemperature diffusion phase formation processes in nanoscale film compositions Pt/Au/Fe.
Methods. The film compositions were deposited by magnetron sputtering;
the structural properties of the asdeposited and annealed films were analysed by xray diffraction method and secondary neutral masspectroscopy.
Results. It was shown by SNMS depth profiles and XRD measurements that the provision of additional Au layer leads to diffusion intermixing of Pt and Fe layers acceleration and to the formation of partially ordered L10FePt phase.
Conclusions. The introduction of the additional intermediate Au layer leads to the enhancement of the lowtemperature intermixing of nanocrystalline Fe and Pt thin films. The intermixing at relatively low temperatures is caused by the grain boundary diffusion induced reaction layer formation mechanism. At the same time the ordering is also enhanced, leading to the appearance of the chemically ordered L10 FePt phase, which results in a strongly increased coercive field. The enhanced chemical L10 ordering is interpreted by stresses developed during the formation of the disordered A1 FePt phase along the GBs: in some of the new grains formed, where there is compressive stress along the {001} direction, chemical ordering can take place.
Keywords: magnetic recording; film composition; FePt; lowtemperature homogenization; chemical ordering.
The Cutting Forces at Thin Cubonit Grinding of the WearResistant Composite NickelBased Parts for Printing Machines /Gavrish А.P., Roik Т.A., Kyrychok Р.O., Khokhlova R.A. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. The investigation of the influence on the cutting forces rectangular components of technological factors at thin cubanite grinding of parts made of wearresistant composite materials synthesized based on the use of recycled and regenerated waste products of nickel alloys XH55BMTKЮ, XH50BTФKЮ, ЭП975 with the addition of solid lubricant CaF2 is presented.
Objective. The purpose of the paper is the experimental research of cutting forces rectangular components of technological processes of thin cubanite grinding of friction parts made of new nickelbased composite materials. The influence on the force field of grinding tool grain, such as bond type grinding discs and basic grinding modes, is determined.
Methods. Surface treatment of printing machine friction parts made of wearresistant nickelbased composites with thin grinding on the plaingrinding machines with cubonit grinding instruments with 14–20 µm grain on the bakeliterubber bond Бр1 and use of the thin cutting modes.
Results. It was show, that the granularity, grinding disc bond material and thin cubonit grinding modes essentially influence the cutting forces rectangular components Px, Py, Pz at grinding of the new nickelbased composites. The cubonit discs with 14–20 µm grain on the bakeliterubber bond Бр1 and use of the thin cutting modes provided the best results.
Conclusions. It is proved that the grain and the grinding cubanite discs bond type and grinding modes significantly influence the formation of the force field at grinding of new nickelbased composite materials. The recommendations were developed for the production.
Keywords: new composite materials; cutting forces; grinding cubonit discs; grain; bond type; cubonit grinding; cutting modes.
Diffusion Titanium Aluminizing of Nickel with (Ti, Zr)N Barrier Layer /Khyzhnyak V.G., Datsyuk O.E., Bilyk I.I., Karpets M.V. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. The prevention of surface oxidation of hightemperature nickelbased alloys is possible by using diffusion coatings, composed of layers of barrier functions. The last inhibit undesirable redistribution of elements at high temperatures.
Objective. The aim is to establish the possibility of education in the nickel diffusion titanaluminum cover with a layer of (Ti,Zr)N, the research phase and chemical composition, structure, properties.
Methods. The barrier layer is deposited by physical vapor deposition. Titanium colorizing has been carried out in the powder mixture of Ti, Al, Al2O3, NH4Cl in the container with fusible gate for 4 hours at 1050 °C. The obtained coatings were stu died by modern methods of materials science: Xray diffraction, microprobe, metallographic and other physicmethods.
Results. The possibility of the coating formation on nickel with Ni2Ti4O, NiTi, Ni2AlTi, Ni3 (AlxTi1 x) compounds, and the transition zone is established as well as the effect of the thickness of the barrier layer (Ti,Zr)N on the coating structure. The barrier layer thickness of 5.5–6.0 microns promotes the formation of jointing zone above the (Ti,Zr)N layer restricts a thickness of the transition zone, eliminates the formation of the Ni (Al,Ti) layer in the jointing zone, and Ni (O)layer in the transition zone.
Conclusions. It is found that during the process of titaniumaluminizing of nickel diffusion zone is formed on the basis of oxides, intermetallic compounds of titanium and aluminum, of (Ti,Zr)N layer with high micro hardness. The investigated coating may be promising for the production of nickel and its alloys at high temperature operating conditions.
Keywords: nickel; titanium; aluminum; barrier layer; oxides; intermetallic compounds; nitrides; micro hardness.
calibration and correction Method of the output signals of the triaxial accelerometer /Avrutov V.V., Golovach S.V., Sapegin О.M., Xutko M.Yu. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. Calibration is one of the most important stages of work for putting into operation such navigation sensors as accelerometers.
Objective. The aim of this study is to investigate the possibility of using the calibration and correction method of the output signals of the triaxial accelerometer.
Methods. To work with the model outputs matrix methods of linear algebra are used. In particular, determining the unknown parameters of the model is based on the method of least squares. Correction algorithm is given in the form of a matrix notation for solving system of linear equations. Such methods of mathematical statistics as the standard deviation and the mathematical expectation were used for the output signals correction estimation.
Results. Formulas for calculations of calibration parameters were obtained, and correction link for output accelerometer signals was developed. Experimental calibration was organized and the data obtained by the algorithm of calibration and correction link was processed. The results of studies for several test samples of triaxial accelerometers are presented.
Conclusions. Using the calibration coefficients, which combine error scale factors and nonorthogonal axes errors can significantly reduce the computational load on the electronic signals processing unit and make output signals with a satisfactory accuracy.
Keywords: navigation sensors; accelerometers, calibration; output signals correction; Allan variation.
Comparative Analysis of the Efficiency of Fiber Winding Types Used in the FiberOptic Gyro Sensor Coil Under Temperature Variation Conditions /Ivanov S.V. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. The paper is devoted to the study of the effectiveness of different types of coil fiber winding of fiber optic gyro (FOG) in reducing of the impact of Shupe effect under temperature changes.
Objective. The objective of the study is to evaluate the effectiveness of different types of FOG fiber coil winding under temperature changes.
Methods. Based on the analysis of existing types of winding, and formulae for nonreciprocal phase shift calculation, a method for evaluation of the impact of temperature gradient on coils with different types of winding is created. Method mentioned is applied to 9 different types of coil winding.
Results. The dependencies of zero shift vs time for nine types of winding under the impact of axial, radial temperature gradients and combinations thereof are obtained.
Conclusion. Overall, use of quadruple windings seems to be optimal; for low precision sensors one can recommend centered unipolar winding while ensuring good thermal and vibration insulation of the coil. The use of pads (or frameless coils) is justified when simple winding is used (e.g., in devices for shortliving objects, for automotive industry, etc.), or for highprecision sensors.
Keywords: fiberoptic gyroscope; fiber winding; Shupe effect.
Geometrical Noise Bandwidth of the Optical Spectrum Analyzer /Kolobrodov V.G., Tymchik G.S., Kolobrodov М.S. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. Coherent optical spectrum analyzers (COSA) are widely used in data processing systems. The efficiency of the spectrum analyzers is determined by their generalized characteristics such as the operating range of spatial frequencies, spatial bandwidth, the spatial spectral resolution and the energy resolution. One of such characteristics is geometric noise bandwidth GNBW that determines the spatial spectral resolution of spectrum analyzer.
Objective. The purpose of this article is to provide a physical and mathematical model of COSA for calculating its geometric noise bandwidth, which determines the spatial spectral resolution of the spectrum analyzer.
Methods. Based on the analysis of physicalmathematical model of COSA invited to determine the field amplitude at the output of the spectrum analyzer using the geometric noise bandwidth.
Results. It was found that the spectrum analyzer can be considered as a coherent optical invariant linear system characterized by the impulse response and a transfer function. The geometric noise bandwidth of COSA is equal the square of the input transparency, amplitude transmittance of which is determined by the amplitude of the investigated signal.
Conclusions. Analysis of the developed physical and mathematical model of the COSA showed that the geometric noise bandwidth is one of the important characteristics of the spectrum analyzer as it allows us to calculate the spatial spectral resolution. It was found that the coherent transfer function of the optical spectrum analyzer is equal to the square of the input transparency, amplitude transmittance of which is determined by the amplitude of the investigated signal.
Keywords: optical spectrum analyzer; geometrical noise bandwidth; spectral resolution.
Hilbert Transform Utilization for Additional Informative Features Receiving at the Pulsed Impedance Testing of Composite Materials /Suslov E.F., Eremenko V.S., Protasov A.G., Pavlenko J.O. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. The article is devoted to the problem of the information increasing for the impedance method of nondestructive testing. This method is one of the commonly used in aviation for testing honeycomb panels and sandwich structures made of composite materials.
Objective. The purpose of this article is to get for the pulsed impedance method of nondestructive testing the additional informative features which increase testing reliability of composite materials.
Methods. It was experimentally measured signals from defective and defectless areas of the test pattern. Utilization of the Hilbert transform gave possibility to determine phase characteristics of these signals and realize demodulation to extract a lowfrequency envelope for further analysis of its shape.
Results. It was received the informative features as a result of researches. Among them are instantaneous frequency of a signal, the integral of a phase characteristic on the selected interval and the integral of a difference signal phase characteristics. In order to compare quality of the defect detection using selected parameters it was carried out evaluation of the testing result reliability for a product fragment made of a composite material.
Conclusions. The proposed informative features characterize a degree of phase characteristics difference and enable to increase general reliability of composite materials testing by the pulsed impedance method.
Keywords: impedance method of testing; Hilbert transform.
Method of Determination of RMS Exposure of Extended Source Image by Microphotometry /Chyzh I.G., Holembovskyi O.O. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. Among the parameters and functions to assess the quality of images formed by optical systems RMS spot diagrams parameter is used. This option is usually defined by beam raytracing going through optical system. There is a fundamental ability to regenerate RMS by microphotometry of image of real point light sources. However, the RMS of the image is distorted due to finite size source. The problem is that the separation of RMS components values, which are caused by the parameters of the light source and the optical system aberrations.
Objective. The recovery of RMS aberration component based on the results of microphotometry of image of extended source of radiation generated with optical system to be tested.
Methods. The mathematical tools polar calculations were used, axial and centrifugal RMS from distribution function of illumination in the image of the extended light source, close to the spot. The calculations of mentioned RMS types are conducted by the radii formulas for moments of inertia that are known in theoretical mechanics. Analogue mass they contain is spatial density of luminous flux in the optical image source. In calculating of RMS the source length is included using Huygens Steiner theorem.
Results. New mathematical observations for calculation of RMS including illumination distribution in the image of light sources are obtained. It was established that RMS of each type is Pythagorean sum of components, one of which is specified by the parameters of the source, and the other by the aberrations of the optical system. According to the results of the regenerated RMS from microphotometry of the image of source and the data on the source parameters aberrational component can be determined in each RMS type.
Conclusion. The study confirms the possibility of determining the aberration RMS of the optical system according to the results of microphotometry of image of extended light source. The method allows creating new photoelectrical hardware for measuring distances to objects, and to create new types of ophthalmic devices.
Keywords: RMS image extended source; RMS operating spots; microphotometry image light source.
Inhibition Corrosion of Zinc in Concentrated Alkaline Electrolyte by Combination of Organic and Inorganic Compounds /Pogrebova I.S., Prihodko G.I. K.: Naukovi visti NTUU “КPІ”. – 2016. – N 1
Background. Zinc is widely used in chemical current sources (CCS) with alkaline electrolytes. One of the promising ways of selfdischarge reduction and the service life improvement of the CCS is the use of zinc corrosion inhibitors. However, nowadays there is only a small number of known compounds that inhibit the corrosion of zinc alkaline, and the mechanism of the protective action of poorly understood.
Objective. The objective is to study the influence of nitrohen, oksyhen and sulfurcontaining organic compounds and their combinations with inorganic matter on corrosion of zinc in concentrated alkaline electrolyte, identifying the mechanism of their protective effect.
Methods. The research was carried out by massmetrical, volummetrical and electrochemical methods with sheet (brand U0) and powder zinc 10 M in KOH and in the same solution with inhibiting additives. Adsorption studies were performed by method of electrocapillary curve removal on a mercury electrode. Mixture state of organic and inorganic compounds was studied by NMR spectroscopy. Zinc surface state was studied by Auger spectroscopy coupled with ion etching after corrosion tests.
Results. Combinations of polyoxyethylenealkyl ethers (FC VIS15, DS10, OP4) and benzotriazole with salts of calcium and magnesium show high protective properties during zinc corrosion in 10 M KOH. Protection degree of zinc electrode if any exists reaches 75 %. Inhibitors inhibit the process of hydrogen evolution in alkaline electrolytes but they do not affect significantly on anodic dissolution of zinc.
Conclusions. There is the improvement of protective effect of organic inhibitors if there is calcium and magnesium in alkaline solutions. The obtained results indicate the prospects of using studied corrosion inhibitors in chemical power sources with zinc anode and alkaline electrolyte.
Keywords: alkaline corrosion of zinc; combination of organic compounds and salts of calcium and magnesium; energyblocking mechanism for inhibiting corrosion; electrochemical infiltration and formation of metal hydroxides.