Measurements Of Thermal Conductivity Coefficient Research Articles

Investigation of mechanical properties and thermal conductivity coefficients of 3D printer materials

The demand for 3D printer technology and products, one of the additive manufacturing methods, is increasing daily in the sectoral and academic fields. Many types of polymer-based filaments are used in 3D printers, pure or filled/reinforcement. Utilizing these specialized materials in places suitable for their mechanical and thermal properties will help efficiently use resources. Using 3D printers, it is possible to manufacture products that provide thermal insulation or good heat conduction in heating and cooling areas. Especially due to the energy requirements for heating and cooling, it is very important to know the thermal performance of materials to ensure and maintain energy efficiency. This study experimentally investigated the mechanical properties and heat conduction coefficients of 3D printed parts. The experiments were conducted with seven different filament materials (PLA, PLA+, PLA-CF, PLA Wood, Tough PLA, ABS+, TPU) and three layer thicknesses (0.1, 0.2, and 0.3 mm). Samples for tensile testing, hardness, and thermal conductivity coefficient measurements were produced, and measurements were performed. In the experiments, the highest tensile strength was obtained in PLA-CF with 0.3 mm layer thickness, and the lowest tensile strength was obtained in PLA Wood with 0.3 mm layer thickness. Tensile strength decreased with an increasing layer thickness in PLA, PLA Wood, ABS+, and TPU, while it increased in PLA-CF. The highest tensile strength of PLA+ was determined to be 0.2 mm and 0.1 mm layer thickness in Tough PLA. Hardness results showed minimal change in hardness values with increasing layer thickness. The thermal conductivity values of the samples varied according to the additives and layer thicknesses. The highest thermal conductivity increase was measured in PLA-CF with 11.84%, and the lowest thermal conductivity decrease was measured in Tough PLA with 9.44%.

A tribological performance of vegetable-based oil combined with GNPs and hBN nanoparticles on the friction-wear tests of titanium grade 2

In this study, friction performance, surface textures, and wear mechanisms of Titanium Grade (Gr) 2 material were investigated with a pin-on-disc tester. The study was carried out under dry, basefluid (vegetable-based oil), graphene nanoplatelets (GNPs), hexagonal boron nitride (hBN) nanofluids, and GNPs+hBN hybrid nanofluid conditions. In addition, the fluid's viscosity and thermal conductivity coefficient measurements were carried out. As the performance criterion of the pin-on-disc test, coefficient of friction (COF), vibration peak values, surface roughness (Ra profile), and topography, wear and wear mechanisms were preferred. With the data obtained after pin-on-disc tests, it can be said that the GNPs+hBN hybrid nanofluid condition shows the best performance compared to other conditions. GNPs+hBN hybrid condition, compared to the dry condition, decreased the COF average, vibration average, and Ra values by 20%, 52%, and 62%, respectively.

Heat transfer in Ar and N2 doped solid CO

The measurements of thermal conductivity coefficient of a solid carbon monoxide crystal containing argon and nitrogen admixtures at different concentrations (1.5, 3, 6, 12.5, 25% for N2 and 0.5, 1, 1.25, 2, 4% for Ar) were performed in the temperature range from 1.5 to 40 K by steady-state heat flow method. For analysis of the experimental data the Callaway method in the framework of the Debye model was used. The contribution of various mechanisms of phonon scattering, including scattering by disordered dipoles of the CO matrix, to the thermal conductivity of CO–N2 and CO–Ar solid solutions were taken into account.

Methods of measurements of thermal conductivity coefficient of polymers. Part II. Direct methods

Methods of measurements of thermal conductivity coefficient of polymers. Part II. Direct methods

Methods of measurements of thermal conductivity coefficient of polymers. Part I. Indirect methods

Methods of measurements of thermal conductivity coefficient of polymers. Part I. Indirect methods