Yazar "Gönül, Alişan" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim
    Öğe
    Comparative analysis of cement-based and historic gypsum-based mortars for historical Restoration: Implications on mechanical and thermal compatibility
    (2025-09-01) Doğruyol, Murat; Gönül, Alişan; Başboğa, Mustafa
    The restoration of historic building façades presents challenges worldwide, especially in terms of maintaining the structural integrity and thermal performance of the original materials. This study aims to evaluate the compatibility of different mortar types used in historical restoration, specifically comparing gypsum-based and cement-based mortars. To achieve this, a comprehensive experimental approach is employed, integrating chemical (SEM, XRD, TGA, and FT-IR), mechanical, and thermal analyses. The study presents a comparative analysis of gypsum-based mortar used in 200-year-old historic Cas houses in Siirt (Southeast of Türkiye) and cement-based mortars used in restoration and conservation applications. Findings indicate that gypsum-based mortars exhibit superior compatibility with historic masonry structures due to their porous and flexible nature, reducing structural stress and improving thermal balance. Conversely, cement-based mortars contribute to significant structural damage in historic masonry due to their rigid nature, leading to shear stress failures, particularly in seismic regions. This research provides novel insights into the role of material selection in heritage conservation, emphasizing that cement-based mortars may not be suitable for historic restorations due to their mechanical and chemical incompatibilities. Instead, the study highlights the importance of using traditional materials, such as gypsum-based mortars, to maintain the long-term durability and authenticity of historic structures.
  • [ X ]
    Öğe
    Pressure Drop and Heat Transfer Characteristics in a Microchannel with Pin-Fins
    (Avestia Publishing, 2024) Gönül, Alişan; Karayiannis, Tassos G.
    Pin-fin heat sinks are now considered one of the possible solutions for the thermal management of small-scale devices requiring high heat dissipation rates. Pin-fins with fixed diameters, different heights and spacing were numerically investigated in the current study for a range of Re=200-1000. The micro-channel cross-section with pins at the bottom surface measures 55 mm in length and has a cross-sectional area of 1 mm x 1 mm. The fin height ranges from 0.2 to 0.8 mm and the distance between pin-fins ranges from 3-6 mm. The fins had a circular cross section 0.25 mm in diameter. The Box-Behknen method was used to determine the number of numerical runs based on the parametric range of pin height and spacing and the Re number. Input data and corresponding outputs were presented using the Genetic Aggregation Response Surface Methodology. An optimum pin height and spacing in terms of heat transfer rates was obtained. It has been observed that at the optimum design, considering the highest Performance Evaluation Criteria (PEC) value the microchannel with pin-fins, can provide an enhancement of 364% in heat transfer rates compared to the microchannel without pins, while the corresponding increase in pressure drop reaches up to 162%. Correlations are proposed for heat transfer and pressure drop calculations able to predict the numerical results mostly within 10%. © 2024 Authors.