Establishment of regularities of influence on the specific heat capacity and thermal diffusivity of polymer nanocomposites of a complex of defining parameters

Fialko, Nataliia; Dinzhos, Roman; Sherenkovskii, Julii; Meranova, Nataliia; Aloshko, Sergii; Izvorska, Diana; Korzhyk, Volodymyr; Lazarenko, M. M.; Mankus, Iryna Volodymyrivna; Nedbaievska, Liudmyla

doi:10.15587/1729-4061.2021.245274

Cited by 8 publications

(2 citation statements)

References 10 publications

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“…Various aspects of the study of the most important thermophysical properties of polymer micro-and nanocomposites -their heat conductivity and specific heat capacity are reported in many works [1][2][3][4][5][6][7][8][9][10][11][12]. As for the thermally conductive properties of composite materials, special attention is paid to their study.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

“…Nevertheless, in some studies, for example, [11], the study of the specific heat capacity of polymer composites covers various aspects relating to the establishment of its temperature, concentration, and technological dependences. In the cited work, a series of experimental studies are carried out to establish the regularities of the complex effect on the specific heat of polymer nanocomposites of such factors as the temperature regime of their production, the value of the mass fraction of filler, and temperature of the composite material.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

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Establishing the influence of the type of micro- and nanofillers on the thermophysical properties of highly heat conductive polymer composites based on polyamide 6

Fialko

Dinzhos

Sherenkovskii

et al. 2022

EEJET

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The object of this study is the thermophysical properties of polymer micro- and nanocomposites, as well as the dependence of their heat conductivity with structural characteristics when using different types of fillers. A set of experimental studies of heat conductivity and specific heat capacity of polymer micro- and nanocomposite materials for polyamide 6 and carbon nanotubes, copper and aluminum as matrix and fillers was carried out. When obtaining composites, a method was used that is based on the mixing of components in the polymer melt. The content of fillers varied from 0.3 to 10 %, and the temperature of composite materials – from 305 to 500 K. Experimental dependences of heat conductivity coefficients of the studied composites on the content of the filler were derived. It was established that according to the value of these coefficients in order of their reduction, these composite materials are ranked as follows: composites with fillers with carbon nanotubes, copper, and aluminum. It was found that only one percolation threshold is observed, when using a polyamide 6 matrix. The regularities of changes in the specific heat capacity of the composites under consideration on their temperature when varying within the above limits of the filler content were investigated. The analysis of the influence of the content of fillers on the degree of crystallinity of the polymer matrix of the investigated composite materials was carried out. It is shown that with an increase in the content of fillers, the degree of crystallinity decreases. The relationship between the thermally conductive properties of the composites under consideration and the specified degree of crystallinity has been established. Higher values of heat conductivity of composites correspond to lower values of the degree of crystallinity. The reported results can be widely used in the development of highly heat conductive composites for various engineering applications.

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Section: Literature Review and Problem Statementmentioning

confidence: 99%

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Establishing the influence of the type of micro- and nanofillers on the thermophysical properties of highly heat conductive polymer composites based on polyamide 6

Fialko

Dinzhos

Sherenkovskii

et al. 2022

EEJET

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Finite-dimensional perturbation of the Dirichlet boundary value problem for the biharmonic equation

Berikkhanova

2024

Zeitschrift Für Naturforschung A

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The biharmonic equation is one of the important equations of mathematical physics, describing the behaviour of harmonic functions in higher-dimensional spaces. The main purpose of this study was to construct a finite-dimensional perturbation for the Dirichlet boundary value problem associated with the biharmonic equation. The methodological basis for this study was an integrated approach that includes mathematical analysis, algebraic methods, operator theory, and the theorem on the existence and uniqueness of a solution for a boundary value. The main tool is a finite-dimensional perturbation, which allows for examining the properties and behaviour of boundary value problems in as much detail as possible. In the study, descriptions of correctly solvable internal boundary value problems for a biharmonic equation in non-simply connected domains were considered in detail. The study is also devoted to the search for solutions and the analytical representation of resolvents of boundary value problems for a biharmonic equation in multi-connected domains. Within the framework of the study, theorems and their consequences were proved, and a finite-dimensional perturbation was constructed for the Dirichlet boundary value problem. Analytical representations of resolvents of boundary value problems for a biharmonic equation in multi-connected domains were also obtained. The examination of a finite-dimensional perturbation of the Dirichlet boundary value problem for a biharmonic equation has expanded the understanding of the properties of this equation in various contexts.

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Validating the First Law of Thermodynamics for Unsteady Flow in a Compression Wave Using Mathcad

Ryndin,

Karmanov,

Kinzhibekova

et al. 2024

Heat Trans Res

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Classical thermodynamics traditionally overlooks the role of quantities dependent on spatial coordinates and time, especially in the context of unsteady flows. This research introduces the first law of thermodynamics (FLT) tailored for nonstationary flow, distinguishing itself with the inclusion of terms bearing partial derivatives of pressure, p(x, t), concerning coordinates and time (-ν(∂р/∂х)dx; -ν(∂р/∂t)dt). By employing this novel approach, the derived equations are validated using a centered compression wave as a representative nonstationary flow case study. A methodology is also presented for experimentally quantifying hydrodynamic energy losses in the intake and exhaust systems of internal combustion engines. Central to the exploration is the calculation of pressure forces' work (-ν(∂р/∂х)dx and -ν(∂р/∂t)dt) in the FLT equation for nonstationary flows, particularly their applicability to a centered compression wave. Moreover, a distinct procedure for discerning friction work in nonstationary flow is delineated. The research methods encompass both analytical derivation and numerical simulations leveraging Mathcad software. The bespoke Mathcad program crafted for this study can graphically represent multiple flow parameters as functions of time, proving invaluable for comprehending compression wave dynamics and evaluating friction work in diverse unsteady flows. Ultimately, the incorporation of energy equations tailored for nonstationary flows into classical thermodynamics paves the way for a more comprehensive understanding and application of thermodynamics to intricate flow scenarios.

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Establishment of regularities of influence on the specific heat capacity and thermal diffusivity of polymer nanocomposites of a complex of defining parameters

Cited by 8 publications

References 10 publications

Establishing the influence of the type of micro- and nanofillers on the thermophysical properties of highly heat conductive polymer composites based on polyamide 6

Establishing the influence of the type of micro- and nanofillers on the thermophysical properties of highly heat conductive polymer composites based on polyamide 6

Finite-dimensional perturbation of the Dirichlet boundary value problem for the biharmonic equation

Validating the First Law of Thermodynamics for Unsteady Flow in a Compression Wave Using Mathcad

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