The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform

Leyla Ozturk - One of the best experts on this subject based on the ideXlab platform.

  • compressive strength color change relation in mortars at High Temperature
    Cement and Concrete Research, 2004
    Co-Authors: Nabi Yuzer, Fevziye Akoz, Leyla Ozturk
    Abstract:

    Changes in materials' physical, chemical and mechanical properties have to be known to decide whether the buildings exposed to High-Temperature Effect will be repaired or demolished. In order to carry out the Effects of fire and extinguishing on the properties of concrete, mortars with and without silica fume were exposed to different Temperatures, such as 100, 200, 300, 600, 900 and 1200 °C, and cooled slowly in the air and fast in water in two groups. Flexural and compressive-strength tests were performed on the samples which were cooled up to room Temperature and changes in color were determined by using the Munsell Color System. High Temperature has caused damages in mechanical properties of mortars with or without silica fume, especially samples which were cooled in water, which showed significant decrease in mechanical strengths at 600 °C. In this study, it was observed that the changes in color's hue component and the compressive strength have similarities. Test results show that residual color changes in mortar can give an idea about the Effect of High Temperatures on the mechanical properties of mortar during a fire.

Hongwei Wu - One of the best experts on this subject based on the ideXlab platform.

Yan Bai - One of the best experts on this subject based on the ideXlab platform.

  • operation of air cooled condensers for optimised back pressure at ambient wind
    Applied Thermal Engineering, 2018
    Co-Authors: Yan Bai
    Abstract:

    Abstract The traditional back pressure regulation of turbine is influenced more seriously by ambient wind and Temperature, especially the hot air reflow and High Temperature Effect on the axial fans of the air-cooled condensers. This variation would result in the cooling capacity of the fans decreasing and the power consumption increasing. The grey difference incremental correlation method is proposed for considering the back pressure regulation problem from a single condenser cell perspective, and analyze the influence on the heat rejection when processing the speed regulation of the axial fans, then the relationship between the heat rejection increment and the influence of the back pressure will be obtained. The flow and Temperature fields of the air-cooled condensers can be obtained by applying the CFD method, and the different back pressure in the different fan speed will be calculated. The results show that, larger the fans ventilation rates will not necessarily cause Higher the heat rejection of the finned tube bundle. Reasonably improve the speed of the Higher relational degree fans can Effectively reduce the turbine back pressure and save energy.

P A Nagorny - One of the best experts on this subject based on the ideXlab platform.

  • High pressure High Temperature Effect on melt textured yba2cu3o7 δ High Temperature superconductive material
    Journal of Materials Science, 2000
    Co-Authors: T A Prikhna, W Gawalek, F Sandiumenge, V E Moshchil, V S Melnikov, T Habisreuther, A B Surzhenko, P A Nagorny
    Abstract:

    High pressure-High Temperature (HP-HT) treatment of melt-textured YBa2Cu3O7 − δ at 2 GPa, and in the 800–950 °C pressure-Temperature range for 15–30 min in contact with monoclinic pre-annealed zirconia induces: (1) the increase of the material density from 5.7 to 6.3 g/cm3 (by 9%), (2) the increase of critical current density in the direction of c-axis of YBa2Cu3O7 − δ grains from 3–3.5 × 103 up to 7 × 103 A/cm2 (in the self-field at 77 K) while in the ab-plane it remains unchanged (104 A/cm2), (3) the increase of Vickers microhardness from 3.95 up to 5.3 GPa (estimated under the 4.91-N load). The increase in dislocation density in the (001) planes of HP-HT treated YBa2Cu3O7 − δ grains from 108 up to 1012 cm−2 may be one of the reasons of the increase in critical current density. The spaces between twin domains in YBa2Cu3O7 − δ before treatment were 100–150 nm. Completely detwinned wide areas or regions, where each second twin domain was narrowed to approximately 20 nm or tapered down to zero thickness within the first domain and the disappearance of 1/6 〈 301〉 stacking faults have been observed in the treated samples.

Nabi Yuzer - One of the best experts on this subject based on the ideXlab platform.

  • compressive strength color change relation in mortars at High Temperature
    Cement and Concrete Research, 2004
    Co-Authors: Nabi Yuzer, Fevziye Akoz, Leyla Ozturk
    Abstract:

    Changes in materials' physical, chemical and mechanical properties have to be known to decide whether the buildings exposed to High-Temperature Effect will be repaired or demolished. In order to carry out the Effects of fire and extinguishing on the properties of concrete, mortars with and without silica fume were exposed to different Temperatures, such as 100, 200, 300, 600, 900 and 1200 °C, and cooled slowly in the air and fast in water in two groups. Flexural and compressive-strength tests were performed on the samples which were cooled up to room Temperature and changes in color were determined by using the Munsell Color System. High Temperature has caused damages in mechanical properties of mortars with or without silica fume, especially samples which were cooled in water, which showed significant decrease in mechanical strengths at 600 °C. In this study, it was observed that the changes in color's hue component and the compressive strength have similarities. Test results show that residual color changes in mortar can give an idea about the Effect of High Temperatures on the mechanical properties of mortar during a fire.