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The purpose of this paper is to characterize carbide coatings obtained by thermo reactive diffusion (TRD) method on AISI 52100 and 440C bearing steels, which are extensively used in industry, and to study wear behaviour of coated steels at elevated temperatures.

For coatings of vanadium and titanium carbides, TRD treatment is performed on AISI 52100 and 440C steels using pack method at 950°C for 3 h. Carbide coatings are characterized using X‐ray diffraction (XRD). The Daimler‐Benz Rockwell‐C adhesion test and micro‐Knoop indenter is used to assess the adhesion and hardness of the carbide layers, respectively. Ball‐on‐disc arrangement is used for determination of tribological properties of carbide‐coated steels. Friction and wear tests are carried out against Si₃N₄ ball at elevated temperatures up to 600°C under 5 N load, for sliding speed of 0.3 m/s.

The presence of carbides formed on AISI 52100 (Ti₆C_3.75 and VC_0.88 phases) and on AISI 440C (Ti₆C_3.75, VC_0.88 and minor Cr₂₃C₆ and Cr₇C₃ phases) is confirmed by XRD analysis. Hardness values of titanium and vanadium carbides on the 52100 and 440C steels are about 2,175‐2,464 and 2,128‐2,433 HK_0.05, respectively. Friction experiments show that this type of coating is more effective than the substrates in regards to achieving lower friction up to 300°C. Above this temperature, the effect of substrate is more dominant on the friction coefficient. Scanning electron microscopy and energy‐dispersive X‐ray analysis results show the presence of the compact oxide layers at elevated temperatures as a result of increased sintering and oxidation of the wear debris.

This paper deals with only characterization of vanadium and titanium carbide coatings and high temperature wear properties of the coated steels.

Carbide coatings obtained by TRD method are satisfactory in terms of high temperature tribological applications in comparison with those produced vapor deposition processes, which are expensive and complicated equipment.

There is no literature about high temperature wear and friction behaviour of TRD carbide‐coated 52100 and 440C steels. In this study, there are new results on high temperature wear of TRD carbide‐coated steels.

The purpose of the study is to provide a dataset about geometrical constructions of early Ottoman tombs for conservation studies. Thus, a proposal for the restitution phase of the damaged tombs aims to develop.

The study is composed of four phases. First, the representative plan and section drawings of early Ottoman Tombs were redrawn; second, a geometrical analysis was made, a proposal table was prepared for the restitution of the damaged tombs; and last, this table was applied to tomb examples and restitution drawings are verified with the original situation of the tombs.

Early Ottoman tombs may be interpreted through geometric shapes, including the square, circle, triangle, octagon, arsin grid and quadrature systems. The arsin grid system provides information about the position of the domes and the height of the drums and windows. Quadrature establishes the highest point of domes and entrances. The proposal table, developed from the obtained results, facilitated the identification of the original elements, including the dome, drum, window and portal. This information is crucial for conducting further studies on restitution.

The abundance and dispersed nature of tomb structures compared to other architectural designs pose challenges in their scholarly examination. The early Ottoman tombs, which experienced an increase in numbers following the Conquest of Istanbul, serve as the initial expressions and embodiments of novel architectural endeavors. Thus, the determination of design ideas of the early Ottoman tombs sheds light on Ottoman architectural practice, which has remained largely unknown and guided the conservation studies of the tombs that have lost their integrity and originality.

Valuable historical monuments have important potential in the context of cultural tourism in cities. In addition, for the protection of these structures, in terms of ensuring social and cultural sustainability, it is also important to transfer these values to future generations.

The social and cultural sustainability of Erzurum Great Mosque is investigated by viewing the social and cultural sustainability of the mosque through the factors created by Chan and Lee and the criteria created by Stubbs.

As a result, the social and cultural sustainability of Erzurum Great Mosque is revealed, allowing us to propose what should be done to transfer the values of this structure, which has historical and cultural significance, and the culture it represents to future generations.

This study contributes to the literature as to evaluate a historical building, in terms of social–cultural sustainability.