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Naukovi visti NTUU “КPІ”. – 2010. – N 2



Kotovskyi V.І.

Studies into the Surface Processes of Heat Transfer of Biological Objects by Thermographic Method

P. 5–9. Fig. 4. Refs.: 8 titles.

In this paper, we elaborate the methods of determining the efficient heat parameters of biological objects. We study heat conduction and capacity on the surface layer of the skin cover by infrared thermography. This research is done under the standard conditions as well as under artificial restriction of blood supply aimed at determining the surface malperfusion as a factor of the pathological states.

Naidenko V.I., Postulga O.S.

Computation accuracy of dispersion characteristic of open comb with combs of infinite thickness

P. 10–15. Fig. 4. Tabl. 2. Refs.: 4 titles.

This paper deals with ratios between the order of the system of linear algebraic equations for the amplitudes of oscillations in resonators and the number of accountable space harmonics that give the most precise solution of dispersion equation for open comb with combs of infinite thickness, using the method of partial areas. We also reveal the dependence between relative difference of the method of partial areas and the factorization method as well as phase shift of zero space harmonic at the period of the comb.

Popov A.О.

Wavelet-Transform of Discrete Signals for Arbitrary Scales

P. 16–23. Fig. 3. Refs.: 13 titles.

We consider the specificity of continuous wavelet-transform of discrete signals. We propose a novel calculation method of coefficients of continuous wavelet-transform. This method can be applied if the mother wavelet function has no exact mathematical expression and is given solely by its samples at the reference time. We also illustrate possible applications of the method on the example of calculation of values of scale adapted mother wavelet function for coefficients of arbitrary dilation and squeeze.

Litvinov V.V., Kosterev N.V., Denisiouk P.L.

Using Pair-Wise Comparison Methods for Determining the Priority of Methods for Providing Static Stability of Induction Motors under Conditions of Multicriterion Choice

P. 24–29.

Tabl. 4. Refs.: 6 titles.

In this paper, we compare Way, Saaty, Cogger & Yu methods to determine the weight coefficients of optimization criteria importance in the problem of obtaining the optimal sequence of using the main methods of increasing the static stability of induction motors. Finally, our research results show that Saaty method is the optimal method for solving this problem.

Golinko I.M., Kovrygo Yu.M.

analysis of the hybrid Control System using the pulse characteristic of the Plant

P. 30–33. Fig. 4. Refs.: 4 titles.

The study provides an insight into a calculation method of transient processes in the hybrid control system by a pulse characteristic of the plant. This approach allows excluding a stage of approximation in calculations of the control system as well as reducing a simulation error due to subjective choice of the structure of approximation dependence. The method can be used by experts on automation for analyzing and tuning of continuous and digital control systems.

Dobrushkin G.A., Danilov V.Y.

Use of discrete wavelet-transform for segmentation and speech signals denoising

P. 34–42. Fig. 7. Refs.: 8 titles.

Based on the components of the wavelet-transform theory, we present an automated method of speech signals denoising, interference cleaning and ADC artifacts refining. We propose a new method of detecting interphoneme transitions in the continuous speech signals as well as logarithmic and moving average criteria that help make a decision on the speech signals segmentation. In addition, we analyze advantages and disadvantages of the proposed criteria. We also show the complexity of automation of the problem solving of speech signal segmentation under the conditions of absence of a priori knowledge on phonemes natures and transition between them.

Yemets’ O.O., Yemets’ E.M., Olhovskiy D.N.

The Optimization of Linear Function on Permutations: Transformation of Permutable Polyhedron to Kind, Necessary for the Use in Karmarkar’s Algorithm

P. 43–49. Refs.: 17 titles.

In this paper, we design the simplex form of permutable polyhedron. It is necessary for application of Karmarkar’s algorithm at solving of auxiliary tasks of linear programming by the method of combinatorial cutting off.

Kuzenkov O.O., Zayseva T.A.

Quality analysis of non-linear bifurcation effects in differential model of dynamic processes

P. 50–54. Fig. 3. Tabl. 1. Refs.: 10 titles.

We address the issue of simultaneous emergence of several bifurcations in the system of two differential equations. The specificity of topology of the system phase space in the environment of complex points of bifurcation diagrams. Finally, we compare the results of simulation of the empathy level dynamics with the results of the empirical research.

Pavliuk O.O., Bidyuk P.I.

The methods of constructing dynamic Bayesian networks

P. 55–62. Fig. 7. Tabl. 4. Refs.: 6 titles.

This study proposes a method of constructing dynamic Bayesian networks based on statistical data. It consists of two phases:  building a static network structure and dynamic structure of the network, which determines the relations between two neighboring time intervals. The structure obtained is used to form the output at each time interval. Finally, we illustrate how this method can be applied to actual data.

Chertov O.R.

Non-Dyadic One-Dimensional Wavelet-Transforms

P. 63–73. Fig. 3. Tabl. 4. Refs.: 19 titles.

In this paper, we prove that a non-dyadic one-dimensional discrete wavelet-transform doesn’t save any additional filter of the dyadic wavelet-transform, except the low-frequency filter of decomposition.

Babych D.V., Daruga V.V., Malezhyk M.P.

Deforming of Elastically Friable Bodies at a Progressing Cracks Initiation

P. 74–82. Tabl. 1. Refs.: 16 titles.

Based on the structural approach with application of a strain-energy method, we construct a continuum model of the bound process of deformation and microdamage of bodies, which are considered to be elastic and friable isotropic materials. Through experiments conducted, we determine that microdamage, progressing with the growth of load, is identified with accumulation of flat circumferential or elliptical microfissures, stochastically dispersed by volume of the bodies. They are formed as a result of structural elements cracking, in which local stresses reach the border of microstrength, which is a stochastic function of coordinates.

Berdnyk O.M., Gayev Ye.О.

Fully Developed Viscous Flow through Rectangular Pipe with an Easily Penetrable Roughness on Walls

P. 83–88. Fig. 5. Tabl. 1. Refs.: 20 titles.

The aim of this paper is to formulate a problem of laminar viscous flow through an endless rectangular pipe with an easily penetrable roughness (EPR) on walls. We solve this problem by utilizing the MATLAB mathematical package. Moreover, we obtain the numeric data on the roughness depth and density. Our research results are tested on some borderline cases that result in the given problems.

Bolotov G. P, Standur S.J., Bolotov M. G, Ryzhov R.N.

Surfacing of Ceramic Materials in the Gas Discharge

P. 89–92. Fig. 3. Refs.: 7 titles.

The paper reveals the research results of surfacing by a decaying discharge in the argon environment of piezoceramics before its welding, soldering and pasting. By employing the method of surface wetting by the distilled water, we determine that processing by a stream of the accelerated ions of working gas effectively removes fatty pollution from a surface. On the experimental side, we also set the optimum zone of a processed surface arrangement in the interelectrode gap. In addition, we show that "dry" ionic processing is an efficient alternative to liquid chemical processing with application of flying solvents.

Sidorenko S.I., Voloshko S.M., Pavlova E.P., Konorev S.I.

Diffusion Growth of Mn4Si7 Silicide Phase Inclusions of Cylindrical Shape in Mn–Si Thin-Film System

P. 93–99. Fig. 6. Refs.: 10 titles.

We study the process of diffusion formation of Mn4Si7 silicide phase inclusions in films, obtained by deposition of Mn and Si (24% Mn + Si) on a substrate of Si (001) monocrystalline silicon. We utilize the methods of X-ray diffraction analysis, electron microscopy, and mass spectrometry of secondary ions for our experiments. Furthermore, computer simulation within the frame of the model of cylindrical inclusions growth in a supersaturated solid solution allows analyzing concentration allocation of the diffusant, which depends on time, kinetics of inclusions growth, etc.

Karpachev Y.A., Pavlyuk V.M., Dyomin U.M.

Experimental Research of Dynamic Characteristics of the Facility for Polyurethane Mixture Coating on Main Pipelines

P. 100–106. Fig. 5. Tabl. 2. Refs.: 5 titles.

This study provides an insight into the research results of the influence of dynamic characteristics of MTU-532 facility on the accuracy of polyurethane mixture coating on main pipelines. To reduce the expenses for costly raw material, we analyze our research results and propose some possible ways of the facility enhancement.

Kubrak A.I., Zhuchenko O.A.

Mathematical model of Thermal Mode Control of Extrusion Process of Polymeric Materials

P. 5–10. Fig. 2. Refs.: 11 titles.

The paper considers an extruder as an object of mathematical modeling. We address the issue of mathematical modeling of the thermal mode control of extrusion process of polymeric materials. Crucially, we develop a mathematical model, which takes into account basic factors, influencing the increase of work efficiency of the extruder.

Kylinich А.A., Doniy О.М.,  Kotlyar S.М.

Mechanical Properties of Casting Alloys of Al–Mg System after Natural Senescence

P. 115–118. Fig. 2. Tabl. 4. Refs.: 6 titles.

We investigate the influence of natural senescence on mechanical properties of АМг5К, АМг6л and АМг10 alloys. We determine that the level of temporal resistance of the break rises to 15 % and 5 %, and the lengthening of alloys rises to 40 % and 10 % for АМг5К and АМг6л alloys after the natural senescence in the course of three years. Accordingly, the level of temporal resistance of the break of АМг10 alloy rises to 3 % and the relative lengthening falls to 70 % after the natural senescence in the course of three years.

Mikulionok I.O.

Research of strands Cooling Process during granulation of thermoplastics

P. 119–123. Fig. 1. Tabl. 1. Refs.: 7 titles.

We study the cooling process obtained on the extrusion unit of polymeric strands. We also compare the obtained results with the results of numerical modeling. The comparison of experimental and calculation data shows their satisfactory convergence that confirms adequacy of the developed mathematical model of the strands cooling process during granulation of thermoplastics to the real process.

Pavshuk V.M., Skachkov I.O., Shevchenko M.V.

On Determining the Relation between Electrode Melting Speed and Impulse Parameters by Mig Welding with Modulated Current

P. 124–128. Fig. 5. Refs.: 7 titles.

The paper proposes the mathematical model for numerical solving of multi-parameter non-linear computational problem for analysis of the electrode melting process in the "electrode–arc" system. This model can be utilized under the conditions of pulsed metal arc welding by using argon or argon-based mixtures as a shielding gas. In addition, impulse parameters are calculated for the pulsed MIG welding. As a result, we obtain an area of impulse parameters which ensures the equality of electrode feed speed to its melting speed.

Gordienko V.I., Kolobrodov V.G.

Designing of the optical system for the thermal imager

P. 129–132. Fig. 1. Refs.: 5 titles.

The paper presents a method of designing of the optical system which provides set characteristics of the thermal imager. Crucially, we illustrate a sample of calculation of a FOV, a focal length, an entrance pupil diameter and the angular resolution of the objective.

Mozharska K.V., Sokurenko V.М.

Decreasing Blinks Influence at the Analysis of an Iridologycal Image of the Eye

P. 133–136. Fig. 5. Refs.: 6 titles.

This paper proposes the algorithm for decreasing the blinks influence at the analysis of the iridologycal image of the eye. It allows improving the reliability and accuracy of pupil's edge detection. Its advantages and efficiency are confirmed by the results of numerical simulations. This algorithm is based on the detection of an encompassing rectangle for all pupil edge points. Each point of the rectangle is connected with the image center. Finally, we remove all edge points on this ray, except the first edge point.

Gerasimenko U.S., Vasyliev G.S., Korolevich A.J., Hodak A.P.

Application of Magnesium Protection from Corrosion in the Hot Water Heating Systems Using the Contact Water Heaters in the City of Alexandria

P. 137–142. Fig. 4. Tabl. 3. Refs.: 7 titles.

In this paper, we consider the corrosion issues of hot water heating systems that use contact water heaters. We show that the lack of corrosion protection methods after one-year service. It is caused by the increase of corrosivity of the environment due to saturation of the water by carbon dioxide. On the experimental side, we conduct the industrial investigations to check efficiency of the magnesium method of corrosion protection in such systems on the sample of boiler installations of the city of Alexandria. The research results show that magnesium protection allows reducing the corrosion rate to 0,05 mm per year at the starting part of the system under the conditions of the maximum flow of water through “SHCHYT” unit and the anodic current of magnesium dissolution on the first stages of experiment on the 4 A level.

Deykun I.M., Poyda V.V., Barbash V.А.

Obtaining of Cellulose from Rape Straw by the Oxide-Organosolv Method of Delignification

P. 143–148. Tabl. 5. Refs.: 7 titles.

The paper studies the cooking process of cellulose from rape straw by the oxide-organosolv method of delignification. We investigate the influence of the basic technological parameters of the process (duration, temperature, liquor/raw material ratio, concentration of peracetic acid and hydrogen peroxide, type of catalyst) on the pulp yield and properties of pulp. Crucially, we determine that application of catalysts in the process of rape straw cooking by the liquors of peracetic acid allows reducing lignin content in the pulp. Molybdenum catalyst acts more selectively on lignin and does not promote hydrolyze of polissaharides. Finally, we obtain mathematical dependences which adequately describe the delignification process of rape straw with peracetic acid.

Krimets G.V., Astrelin I.M., Tolstopalova N.M., Sazonova Ye.Yu.

An Effective Reagent for Perufication of Flow Waters

P. 149–152. Fig. 4. Tabl. 2. Refs.: 7 titles.

In this paper, we make the comparative analysis of efficiency of flow waters perufication by coagulants on the basis of aluminium sulfate - industrial standard (Al2(SO4)3×18H2O) as well as a novel coagulant, synthesized by our technology. The efficiency of coagulants action is tested on the models and real standards of flow waters in the processes of perufication from lees, dyes, some ions of heavy metals. We also set the limits of рН efficient work of the synthesized standard. In addition, the synthesized sample is tested under the industrial conditions in the real flow waters and is recommended to implementation.

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