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Kerpauskas Paulius - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of the Thermal Properties of Socks Knitted from Yarns with Peculiar Properties. Part I. Thermal Conductivity Coefficient of Socks Knitted from Natural and Synthetic Textured Yarns
    2020
    Co-Authors: Čiukas Ričardas, Abramavičiūtė Jovita, Kerpauskas Paulius
    Abstract:

    This study comprised an experimental investigation to determine the Thermal properties of socks manufactured using not only traditional cotton yarns but also yarns of new kinds of fibres such as bamboo and soybean protein fibres, as well as blended yarns such as cotton/seacells and bamboo/flax. The influence of different fibres of the socks mentioned on the Thermal Conductivity Coefficient of plain knits and plated plane knits with textured polyamide (PA) or elastane (Lycra) wrapped with textured polyamide thread was investigated. It was determined that a higher Thermal Conductivity Coefficient is characteristic for knits with textured polyamide (PA) thread: lower – for knits with Lycra thread and those from pure yarns. The variation in Thermal Conductivity depending on the area density, linear density and thickness of plain and plated plain knits was discusedVytauto Didžiojo universitetasŽemės ūkio akademij

  • Evaluating Thermal insulation properties of garment packet air interlayer
    2020
    Co-Authors: Nadzeikienė Jūratė, Milašius Rimvydas, Deikus Juvencijus, Eičinas Juozas, Kerpauskas Paulius
    Abstract:

    In this article, we present an evaluation of the heat exchange processes taking place in the garment packet air interlayers. In the quest to improve garment designs, evaluate their Thermal insulation properties and create new garment materials, it is necessary to evaluate all kinds of heat transfer in the air interlayer. Heat exchange process in the air interlayer manifests itself by conductance, convection and radiation. Thermal evaluation of a garment packet with air interlayers which is based on conductance alone will be incomplete, as it is also necessary to evaluate the influence on the packet’s Thermal insulation of the air interlayer between the human body and the garment’s internal surface . An equivalent Thermal Conductivity Coefficient was proposed to evaluate the total heat transfer in the air interlayer. Methods for calculating a Thermal Conductivity Coefficient for evaluating the garment packet’s Thermal insulation properties were developed.. It was established while evaluating the heat exchanges in the 1 to 10-mm thick air interlayer as a whole, that the equivalent Thermal Conductivity Coefficient varies depending on the air interlayer thickness. A comparative analysis of air interlayer Thermal resistance is presented, which evaluates the garment’s air interlayer Thermal insulation properties by its Thermal conductance and by its combined conductance, convective and radiation processVytauto Didžiojo universitetasŽemės ūkio akademij

V I Zubov - One of the best experts on this subject based on the ideXlab platform.

  • identification of Thermal Conductivity Coefficient using a given temperature field
    Computational Mathematics and Mathematical Physics, 2018
    Co-Authors: Alla F Albu, V I Zubov
    Abstract:

    The problem of determining the temperature-dependent Thermal Conductivity Coefficient is studied. The study is based on the Dirichlet boundary value problem for the two-dimensional nonstationary heat equation. The cost functional is defined as the rms deviation of the temperature field from experimental data. For the numerical solution of the problem, an algorithm based on the modern fast automatic differentiation technique is proposed. Examples of solving the posed problem are given.

  • Identification of the Thermal Conductivity Coefficient in two dimension case
    Optimization Letters, 2018
    Co-Authors: Alla F Albu, V I Zubov
    Abstract:

    In the paper the problem of determining the Thermal Conductivity Coefficient that depends on temperature is studied. The consideration is based on the mixed boundary value problem for the two-dimensional unsteady-state heat equation. The inverse Coefficient problem is reduced to a variation problem. The mean-root-square deviation of the heat flux obtained by solving initial-boundary value problem from the experimental data on the boundary of the considered domain is used as the objective functional. The optimal control problem is solved numerically. The objective functional is minimized using the gradient methods. It is well known that it is very important for the gradient methods to determine accurate values of the gradients. For this reason, in this paper we used the efficient fast automatic differentiation technique, which gives the exact functional gradient for the discrete optimal control problem. The examples of solving the inverse Coefficient problem confirm the efficiency of the proposed algorithm.

  • Identification of the Thermal Conductivity Coefficient Using a Given Surface Heat Flux
    Computational Mathematics and Mathematical Physics, 2018
    Co-Authors: Alla F Albu, V I Zubov
    Abstract:

    The inverse problem of determining a temperature-dependent Thermal Conductivity Coefficient is studied. The study is based on the Dirichlet boundary value problem for the two-dimensional nonstationary heat equation. The cost functional is defined as the rms deviation of the surface heat flux from experimental data. For the numerical solution of the problem, an algorithm based on the modern fast automatic differentiation technique is proposed. Examples of solving the posed problem are given.

  • LION - Identification of Discontinuous Thermal Conductivity Coefficient Using Fast Automatic Differentiation
    Lecture Notes in Computer Science, 2017
    Co-Authors: Alla F Albu, Yury Evtushenko, V I Zubov
    Abstract:

    The problem of determining the Thermal Conductivity Coefficient that depends on the temperature is studied. The consideration is based on the Dirichlet boundary value problem for the one-dimensional unsteady-state heat equation. The mean-root-square deviation of the temperature distribution field and the heat flux from the empirical data on the left boundary of the domain is used as the objective functional. An algorithm for the numerical solution of the problem based on the modern approach of Fast Automatic Differentiation is proposed. The case of discontinuous Thermal Conductivity Coefficient is considered. Examples of solving the problem are discussed.

  • identification of discontinuous Thermal Conductivity Coefficient using fast automatic differentiation
    Learning and Intelligent Optimization, 2017
    Co-Authors: Alla F Albu, Yury Evtushenko, V I Zubov
    Abstract:

    The problem of determining the Thermal Conductivity Coefficient that depends on the temperature is studied. The consideration is based on the Dirichlet boundary value problem for the one-dimensional unsteady-state heat equation. The mean-root-square deviation of the temperature distribution field and the heat flux from the empirical data on the left boundary of the domain is used as the objective functional. An algorithm for the numerical solution of the problem based on the modern approach of Fast Automatic Differentiation is proposed. The case of discontinuous Thermal Conductivity Coefficient is considered. Examples of solving the problem are discussed.

Paulius Kerpauskas - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of the Thermal Properties of Socks Knitted from Yarns with Peculiar Properties. Part I. Thermal Conductivity Coefficient of Socks Knitted from Natural and Synthetic Textured Yarns Ričardas Čiukas
    Fibres & Textiles in Eastern Europe, 2010
    Co-Authors: R. Čiukas, J. Abramavičiūtė, Paulius Kerpauskas
    Abstract:

    * Lithuanian University of Agriculture Department of Heat and Biotechnology Engineering Studentų 15, LT – 53362 Akademija, Kauno r. Lithuania E-mail: paulius.kerpauskas@lzuu.lt Abstract This study comprised an experimental investigation to determine the Thermal properties of socks manufactured using not only traditional cotton yarns but also yarns of new kinds of fibres such as bamboo and soybean protein fibres, as well as blended yarns such as cotton/seacells and bamboo/flax. The influence of different fibres of the socks mentioned on the Thermal Conductivity Coefficient of plain knits and plated plane knits with textured polyamide (PA) or elastane (Lycra) wrapped with textured polyamide thread was investigated. It was determined that a higher Thermal Conductivity Coefficient is characteristic for knits with textured polyamide (PA) thread: lower – for knits with Lycra thread and those from pure yarns. The variation in Thermal Conductivity depending on the area density, linear density and thickness of plain and plated plain knits was discused.

Bettina Kraushaarczarnetzki - One of the best experts on this subject based on the ideXlab platform.

  • experimental study of heat transport in catalytic sponge packings by monitoring spatial temperature profiles in a cooled wall reactor
    Chemical Engineering Journal, 2014
    Co-Authors: Ingo Graf, Annekathrin Ruhl, Bettina Kraushaarczarnetzki
    Abstract:

    Abstract The heat transport characteristics of catalytically coated sponge packings and of a packed bed of spherical shell-catalysts were investigated by performing the exoThermal hydrogenation of benzene in a tubular reactor with cooled wall. Temperatures inside the catalyst beds were monitored at up to 108 different positions. Steady-state temperature distributions in the catalyst beds were used to elucidate effects of support type and, in case of sponges, of pore density, porosity and Thermal Conductivity Coefficient on heat transfer. Smoothed temperature profiles and reduced hot spot temperatures at equal operation conditions and, in particular, at states of equal over-all heat production by reaction are indicative of enhanced heat transport to the cooled reactor wall. The results show that sponge packings exhibit better heat transfer properties than packed beds of particles. When sponge supports are compared among each other, the Thermal Conductivity Coefficient of the solid material was found to have the strongest impact on heat transfer.

Apipong Putkham - One of the best experts on this subject based on the ideXlab platform.

  • CHARACTERIZATION OF Thermal AND MECHANICAL PROPERTY OF LATEX FOAM RUBBER MIXED WITH SILICA AEROGEL-FILLER
    Rajabhat Journal of Sciences Humanities & Social Sciences, 2017
    Co-Authors: Apipong Putkham
    Abstract:

    The main objective of this research aims to determine the effect of silica aerogel- filler on both Thermal and mechanical property of latex foam rubber. The foam rubbers were produced by mixing with silica aerogel varied from 0.00-20.00 phr via Dunlop process. The physical, elemental composition, mechanical and Thermal property of the foam rubber mixed with silica aerogel was determined. It was found that both density and Thermal Conductivity Coefficient of foam rubber, with silica aerogel at 1.00 phr, decreased to 0.196±0.0026 g/cm3 and 0.055±0.0001W/m.K, respectively. Further increase in the amount of silica aerogel increased both density and Thermal Conductivity Coefficient of the foam rubber. Tensile strength also increased with increasing of the amount of silica aerogel. However, Tensile strength decreased when the amount of silica aerogel exceeded 10.00 phr due to large size of aerogel aggregate is formed and reduces the reinforcing effect. In conclusion, both density and Thermal properties of foam rubber mixed with silica aerogel of 1.00 phr is comparable to the property of the commercial insulation.