Yazar "Çay, Vedat Veli" seçeneğine göre listele

Listeleniyor 1 - 7 / 7
  • Küçük Resim
    Öğe
    Eco-friendly building materials containing micronized expanded vermiculite and phase change material for solar based thermo-regulation applications
    (Elsevier, 2021) Gencel, Osman; Sarı, Ahmet; Ustaoğlu, Abid; Hekimoğlu, Gökhan; Erdoğmuş, Ertuğrul; Yaraş, Ali; Sütçü, Mücahit; Çay, Vedat Veli
    Phase change materials (PCMs) have been widely studied to decrease energy consumption and dependency on fossil fuels that causes environmental concerns, and improve building energy efficiency. In this regard, this study aimed to fabricate structural cement based mortar with indoor thermo-regulation function utilizing form stable PCM (FSPCM). FSPCM was made of micronized expanded vermiculite (MEV) impregnated with Lauric-Myristic acid eutectic mixture (LA-MA). The facile direct impregnation method was used for the production of the FSPCM. The cement-based mortars were then manufactured by replacing the FSPCM with sand at 15%, 30% and 45 wt% ratios. The basic properties of the manufactured cement-based mortars such as physical, mechanical, thermal conductivity, thermal energy storage and thermoregulation performance were systematically investigated. With the incorporation of 45% FSPCM, thermal conductivity (0.42 W/mK), bulk density (1239 kg/m(3)) and compressive strength (56.2 MPa) decreased by 60.93%, 39.2% and 85.94%, respectively. In terms of compressive strength, all samples with FSPCM can meet the standard requirements. Differential Scanning Calorimetry (DSC) analysis revealed that the melting temperature and latent heat of FSPCM and FSPCM-included cement mortar (45 wt%) are 32.16 degrees C and 73.70 J/g and 31.96 degrees C and 18.90 J/g, respectively. The thermoregulation performance test indicated that the produced FSPCM-included cement based mortars are able to provide thermal comfort by minimizing indoor temperature fluctuations and thus saving energy by reducing heating-cooling loads in buildings.
  • Küçük Resim
    Öğe
    Effect of abrasive particle sizes on abrasive wear of ceramic coatings sprayed by plasma process
    (2011) Gök, Mustafa Sabri; Gençel, Osman Serden; Koç, Vahdettin; Kuchuk, Y.; Çay, Vedat Veli; 0000-0002-2770-4038
    This study examines the effects of abrasive grain size on abrasive wear behaviors on surfaces coated with different types of ceramics. To this end, the surface of AISI 1040 steel is coated with the ceramic materials of 5% SiO 2-3% TiO 2-92% Cr 2O 3, 60% Al 2O 3-40% TiO 2, pure Al 2O 3 and 87% Al 2O 3-13% TiO 2 using the plasma method. Following the coating process, the abrasive wear resistance of each sample is tested by the ring-on-disc method. 80-220 mesh SiC abrasive paper is used as abrasive. The best wear resistance is obtained with the ceramic coating containing 92% Cr 2O 3, which is followed by pure Al 2O 3 and 87% Al 2O 3-13% TiO 2, respectively. The lowest wear resistance is observed in 60% Al 2O 3-40% TiO 2 ceramic coating. Wear resistance of the samples increases with increasing hardness value and decreasing abrasive grain size. It is observed that wear mechanisms occurring on the samples' wear surfaces change with changing abrasive grain size. Wear mechanisms such as microscratching, microcracking, and plastic deformation are observed in the samples.
  • Küçük Resim
    Öğe
    Effects of abrasive particle type, load and sliding distance on micro-abrasion resistance of high speed steel coated with AlCrN or AlTiN
    (Kaunas Univ Tech, Kaunas Univ Tech Materials Science, 2021) Çay, Vedat Veli
    High Speed Steel (HSS) specimen surfaces were coated with AlCrN and AlTiN via Physical Vapor Deposition (PVD) method for the micro-abrasion wear behavior testing. Wear tests were performed by fixed ball micro-abrasion wear equipment. During the micro-abrasion wear tests, 0.5, 1 and 1.5 N loads were applied for periods of 60 and 180 seconds. In these tests, different kinds of abrasives were used, as alumina (Al2O3) and silicon carbide (SiC). Two different particle sizes were used for each type of abrasive, which are F800 (mean size 6.5 ± 1 µm) and F1200 (mean size 3.0 ± 0.5 µm). During the wear tests, wear loss increased with increasing SiC and Al2O3 abrasive particle size. It was determined that the volume losses formed by SiC abrasive particles on AlTiN and AlCrN coatings to be higher than Al2O3 abrasive particles. Micro-grooving and micro-rolling wear mechanisms were observed when F800 and F1200 abrasive slurry were used, respectively. Volume losses increased with the increase in the applied load and the number of cycles. The AlCrN coatings exhibited better wear resistance than the AlTiN coatings. The applied test load had a significant effect on the wear mechanisms observed
  • Küçük Resim
    Öğe
    Investigation of mechanical and thermal behavior of Basalt Cutting Waste (BCW) added clay brick
    (INESEG Yayıncılık, 2019) Koçyiğit, Şermin; Çay, Vedat Veli
    Porous clay bricks produced by adding 5%, 10%, 15% and 20% by weight ofBasalt Cutting Waste (BCW) were manufactured by semi-dry pressingprocess. BCW (Karacadağ, Diyarbakir, Turkey) was added to brick rawmaterial as an additive in order to increase porosity and strength. Thechemical composition and thermal behaviors of raw materials wereinvestigated and SEM analysis was performed. Brick mixes containingdifferent proportions of BCW were formed and then fired at 900 and 1000° Cfor two hours. Porosity, water absorption, compressive strength, thermalconductivity and microstructure of the samples were examined. It wasobserved that the porosity ratios were increased by up to 34% with theaddition of BCW, however, compressive strength (at least 28 MPa) decreased.However, the compressive strength was found to be higher than the requiredstandards. The thermal conductivity of samples with the addition of 20% BCWdecreased from 0.98 up to 0.72 W / mK compared to the reference sample,which also corresponds to a reduction of 26.5% in proportion to the referencesample along with the increase in porosity. The increase in firing temperaturealso affected the mechanical and physical properties of the samples. Inconclusion, this study revealed that the brick samples produced could beevaluated and used as insulating materials by adding BCW to buildingmaterials in construction applications.
  • [ X ]
    Öğe
    INVESTIGATION OF WEAR BEHAVIOR OF Ti6Al4V /$B{_4}C$ COMPOSITES PRODUCED BY POWDER METALLURGY
    (2020) Çay, Vedat Veli; Koç, Vahdettin
    In this study, Ti6Al4V / B4C Metal Matrix Composite (MMC) was produced using powder metallurgy (PM) method. Ball-milled powders, containing 0, 5, 10, and 15 wt% $B{_4}C$ were hot compacted at 950 °C for 20 minute under 450 MPa pressure in ambient air. The wear tests performed at 300 rpm sliding speed, 300 m sliding distance and three different loads of 5N, 10N, 15N, the effects of Ti6Al4V compound on$B{_4}C$ reinforced wear properties at different rates were investigated. It was determined that composite materials reinforced with $B{_4}C$ powder give better results than unreinforced Ti6Al4V and generally, as the amount of $B{_4}C$ powder increases, the friction coefficient values decrease and the wear resistance increases. In the wear test, it was observed that the friction coefficient of all materials decreased as the load increased. As a result of the changes in$B{_4}C$ reinforcement ratios, differences were observed in wear types and wear track depth. The results of the study showed that the wear resistance increased in parallel with the $B{_4}C$ addition and the best wear resistance was obtained with the wt. 15% $B{_4}C$ added sample.
  • [ X ]
    Öğe
    MECHANICAL PROPERTIES OF THE COMPOSITE MATERIAL PRODUCED BY THE MIXTURE OF EXPANDED PERLITE, WASTE MARBLE DUST AND TRAGACANTH
    (2018) Çay, Vedat Veli; Koçyiğit, Şermin
    In this study, the strength characteristics of the expanded perlite aggregate,waste marble dust and tragacanth added cement based composite materialwere investigated. A composite construction material was prepared usingexpanded perlite aggregate with a particle size of 0-2 mm and 2-4 mm at theratio of 10%, 30% and 50% by weight, waste marble powder produced bysieving through 0.25 mm sieve at the ratio of 10% and 20%, tragacanth at theratio of 0%, 0.5% and %1 and CEMI 42.5 N type Portland cement. Density,compressive strength, abrasion loss, water absorption tests were performedon these prepared composite samples. It was seen that compressive strengthand density values have decreased and abrasion loss and water absorptionvalues have increased as expanded perlite particle size, expanded perliteratio, tragacanth ratio have increased and waste marble powder ratio hasdecreased on the prepared samples.
  • Küçük Resim
    Öğe
    Thermal energy saving and physico-mechanical properties of foam concrete incorporating form-stabilized basalt powder/capric acid based composite phase change material
    (Elsevier Ltd., 2023) Koçyiğit, Fatih; Bayram, Muhammed; Hekimoğlu, Gökhan; Çay, Vedat Veli; Gencel, Osman; Ustaoğlu, Abid
    The incorporation of phase change materials (PCM) in construction materials for the purpose of thermal energy storage (TES) can prevent temperature fluctuations and enable the conservation of thermal energy in buildings. Accordingly, this study aims to create a novel, environmentally friendly foam concrete incorporating a composite PCM composed of capric acid saturated waste basalt powder. Basalt powder, a byproduct of the grinding or crushing of basalt volcanic rock, was selected as a carrier material due to its high porosity resulting from its lightweight and porous nature. This allowed for the creation of a leak-free composite PCM, which was then integrated with foam concrete made of CEM I 42.5R cement, water, quartz sand, and a foaming agent. BasaltPCM was substituted into the mixture at 50% and 100% by weight of quartz aggregate. Comprehensive evaluations were conducted on the novel foam concretes with regard to their morphological, mechanical, physical, thermal, and TES properties. The results indicate that the incorporation of basalt-PCM causes a minor reduction in the dry unit weight of the mixtures and a reduction in compressive and flexural strength. However, the leakproof basalt powder/capric acid composite displayed a phase transition behavior, melting at 28.5 ◦C with a latent heat of fusion (47.9 J/g), which retained 99.5% capacity after 500 melting-solidification cycles. The specimen with 100 wt% basalt-PCM exhibited a melting temperature and latent heat of 27.8 ◦C and 17.4 J/g, respectively. Additionally, the basalt powder/capric composite exhibited high thermal stability up to 156 ◦C, far above its normal operating temperature. The foam concretes incorporating the basalt-PCM demonstrated solar thermoregulation properties, maintaining a more stable and comfortable indoor temperature. These results suggest that the form-stable PCM-incorporating foam concretes developed in this study can be considered as environmentally friendly building materials for thermoregulation and energy conservation.