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Öğe The effect of different fiber reinforcement on the thermal and mechanical properties of autoclaved aerated concrete(Elsevier Sci Ltd, 2016) Pehlivanli, Zuhtu Onur; Uzun, Ibrahim; Yucel, Zeynep Pinar; Demir, IlhamiIn this study, the changes in thermal conductivity value, compression and flexural strength of autoclaved aerated concrete were investigated experimentally by adding polypropylene, carbon, basalt and glass fibers into the G3/05 and G4/06 class autoclaved aerated concrete used as wall elements in buildings and the commercial production of which is made. Fibers were substituted with the aggregate in autoclaved aerated concrete in equal amounts volumetrically. The produced samples were subjected to autoclaved cure as in non-fibrous autoclaved aerated concrete. As a result of the experimental study; it has been seen the thermal conductivity of fiber substituted autoclaved aerated concrete changes linearly with thermal conductivity of the substituted fibers and basalt fiber reinforced autoclaved aerated concrete gives the highest thermal conductivity. But, it has been seen that the best compression and flexural strength was given by the carbon fiber reinforced samples. (c) 2016 Elsevier Ltd. All rights reserved.Öğe Effect of Infiltration Pressure on Thermal Conductivity of Al 2014 Matrix Composite Powered by Silicon Carbide(Asian Journal Of Chemistry, 2012) Ates, Serkan; Uzun, Ibrahim; Çalın, Recep; Citak, RamazanBy using pressure infiltration method, metal matrix composites are produced by saturating Al 2014 aluminum composite to the gaps among SiC powders. SiC powders filled into stainless steel tubes are fastened between the filters conducting only liquid material, dipped into pressurized molten boiler and infiltrated in 3 min under 500-900 kPa pressures at 750 degrees C. The image analyses of samples were done by scanning electron microscope (SEM). Densities, porosities and thermal conductivities of them were identified experimentally. It is defined that by the increase of infiltration pressure, porosity amount decreases but the value of thermal conductivity increases.Öğe Effect of polypropylene fiber length on mechanical and thermal properties of autoclaved aerated concrete(Elsevier Sci Ltd, 2022) Pehlivanli, Zuhtu Onur; Uzun, IbrahimIn this experimental study, the effect of polypropylene fiber (PF) length on the thermal conductivity, pressure and flexural strength values of autoclaved aerated concrete (AAC) was investigated. The investigation used samples from G2/04, G3/05, and G4/06 classes AAC manufacturing in three different density and compressive strength groups. PF of three different lengths, 3, 6, and 12 mm, were chosen as reinforcement material, and AAC samples were made by adding 1.0% in the same volumetric ratios into the matrix material, taking into consideration their specific gravity. After the samples were kept in curing at 60 degrees C for 4 h, they were cured in an autoclave at 180 degrees C at 11 bar pressure for 7 h. After the autoclave process was completed, the flexural and compressive strength, thermal conductivity values of the samples were tested and the internal structure images were examined with a scanning electron microscope (SEM). It was observed that the flexural and compressive strengths of the samples increased with PF reinforcement in all density groups, while the thermal resistances decreased and the fiber length (for 3, 6 and 12 mm) had a positive effect on the compressive and flexural strengths of all examined AAC classes. It was obtained by 70.4% increase in the compressive and flexural strengths of G2/04 class of AAC samples with 12 mm length PF addition. As the PF length increases, the thermal conductivity values of all samples also increase and the highest thermal conductivity increase was observed in the G5/06 class samples with a value of 20.2%. In general, it was observed that the compressive strength, bending strength and thermal conductivity values of all samples increased depending on the increase in PF length. It has been observed that thermal conductivity values are worsen at more higher rates while the strength values of AAC at all fiber lengths is improves with PF additive.Öğe Initial Results of Testing a Multilayer Laser Scanner in a Collision Avoidance System for Light Rail Vehicles(Mdpi, 2018) Luy, Murat; Cam, Ertugrul; Ulamis, Faruk; Uzun, Ibrahim; Akin, Salih IbrahimThis paper presents an application to detect and track obstacles using a multilayer laser scanner. The goal of the detection system is to develop collision avoidance for the Light Rail Vehicle (LRV). The laser scanner, which is mounted in front of the tram, collects information in a four-scan plane. The object recognition and tracking module, which is composed of a three sub-modules segmentation, classification, and Kalman Filter tracking, was carried out on the raw data. Thus, data were provided for collision avoidance module. The proposed system was applied to a tram named "Silkworm" which is manufactured by Durmazlar Machine Inc. (Bursa, Turkey) and initial experimental tests have been conducted at the facilities of Durmazlar Machine Inc. in the city of Bursa, Turkey. This study aims to illustrate parts of the possible tests that can be carried out and to share with the scientific community an important application of multilayer laser scanners, although in the initial implementation phase, in urban rail transportation.Öğe Investigation of mechanical properties AISI 1040 steel welding with electric arc and MIG, applied various heat treatments(Pamukkale Univ, 2017) Ongun, Alemdar; Uzun, Ibrahim; Turgut, Onur KadirIn this study, AISI 1040 welding samples were produced by arc welding and MIG. The full annealing, normalizing, tempering and stress relief annealing treatment was applied for as-received and welded samples. Made process and untreated samples tensile, three point bending, impact and hardness tests were conducted. Tensile strain of the welded parts is higher than in the welded parts. The yield and tensile strength of the as-received and electric arc welded sample has similar value after stress relief treatment. Hard martensitic structure on the outside, inside is seen increasingly become a soft structure. Increasing in hardness was observed starting from the weld filler metal to outside.Öğe Mechanical and microstructural features of autoclaved aerated concrete reinforced with autoclaved polypropylene, carbon, basalt and glass fiber(Elsevier Sci Ltd, 2015) Pehlivanli, Zuhtu Onur; Uzun, Ibrahim; Demir, IlhamiAutoclaved aerated concrete (MC) is a construction material obtained by being pore-forming of the mixture prepared with finely crushed siliceous aggregate lime, water and limestone with the addition of aluminum powder and being cured with steam cure (autoclave). MC is a widely used material today in the constructions as a material that is very light compared to concrete or conventional stone material and that has high insulation properties and fire-resistant light construction material. In this study, the effect of fiber type and size in the production of MC on compressive, flexural strength and thermal conductivity values has been investigated. In the study, G2/04 class having 400 kg/m(3) density of MC production used for wall element and commercially produced was taken as a reference. Fiber types were substituted for an equal amount of aggregate and MC samples were produced. The mechanical properties and thermal conductivity values as well as microstructural features of the sample produced were examined. The samples produced were waited at the temperature of 60 degrees C in 4 h-cure, then they were subjected to the cure at the temperature of 180 degrees C, at the pressure of 11 bar and in an autoclave for 6.5 h. As well as the mechanical properties of the samples produced and thermal conductivity values, their microstructural features were also examined. In the study, it was seen that fiber was supplemented instead of quartzite increased flexural and compressive strength of MC and carbon fiber reinforced MC gave the best flexural and compressive strength compared to fiber types. (C) 2015 Published by Elsevier Ltd.Öğe NUMERICAL ANALYSIS OF NATURAL UNSTEADY CONVECTION HEAT TRANSFER FROM VERTICAL PLATE(Pamukkale Univ, 2005) Uzun, Ibrahim; Terlemezoglu, Nur; Dogan, BattalFor boundary conditions of constant wall temperature, unsteady natural heat transfer at vertical plate have been investigated as numerically. In this study, laminar boundary layer equations have been solved based on Bousinessq assumption. In the computations, Gr and Re numbers have been taken as variables. By using some programs developed for finite difference and finite element codes for the related equations, the velocity and temperature distributions have been obtained. The obtained numerical results were shown with graphics and tables. Results were compared with similarity and integral methods.Öğe Numerical modeling of temperature distribution in a high temperature sintering furnace(Pamukkale Univ, 2024) Akkoyunlu, Turker; Uzun, Ibrahim; Tan, HuesamettinThe development of new energy management systems for sintering processes with high energy consumption and generally carried out with traditional recipes has become an important research topic nowadays. It has been focused on homogeneous temperature distribution in the furnace used in the sintering process. If the temperature difference is high in the furnace, the internal structure of the materials can show serious changes. In this study, transient numerical design and analysis were carried out from room temperature to 1100 degrees C. The temperature changes of the samples placed at different locations in the furnace with the dimensions of 1070x1580x1030 mm were numerically investigated as transiently. In numerical studies, room temperature and initial furnace temperature were defined as the initial conditions. The boundary conditions are given as heat flux on the heater surfaces and convection outside the furnace. At the end of numerical solutions, temperature values were found inside the furnace and on the samples transiently. I t was showed that the temperature differences between the samples were high that is expected at the beginning, but these differences decreased to about 17 degrees C in the steady conditions. Unlike the studies in the literature, the condition of the samples in a protected chamber, not under the influence of direct radiation, was examined and it was observed that the temperature differences decreased by up to 2 degrees C. In the analysis, time-dependent temperature distributions and temperature differences are given comparatively for two different cases.Öğe Sea water effect on pinned joint glass fibre composite materials(Elsevier Sci Ltd, 2008) Aktas, Alaattin; Uzun, IbrahimThe effect of sea water on the bearing strength behavior of the woven glass fibre composite has been investigated experimentally. The ratio of the edge distance to the pin diameter (E/D), and the ratio of the specimen width to the pin diameter (W/D) were systematically varied during experiments. In order to provide the real environmental conditions, specimens were tied to a ship, making voyage in the Sea of Marmara having 2.2% of salt and 22-26 degrees C of surface temperature, with a stainless wire to keep the specimens into sea. The specimens were kept into sea 1, 2 and 4 months. The experiments were carried out according to the ASTM D953 [ASTM D 953-D, Standard test method for bearing strength of plastics. ASTM Designation. p. 342-6]. The results show that while the bearing values obtained from the specimens kept into sea for four months decrease considerably with respect to I and 2 months. But, the failure modes for all configurations are the same mode. Failure distance of the pin displacement increases with the increasing of immersing period owing to softening of the specimen. (c) 2007 Elsevier Ltd. All rights reserved.
