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Öğe Determination of rheological characteristics of flow concrete by artificial neural networks method(2010) Bilgil A.; Tezekici B.S.; Vehbi Gokçe M.Fresh concrete is usually considered as a non-Newtonian fluid since it is a mixture of aggregate, cement and water. The flow behaviour of fresh concrete plays a crucial role in the quality of high performance concretes. Therefore, knowing rheological characteristics of high performance fresh concrete has been an absolute must, to be able to control the behaviour of that type of concrete. But, determining rheological characteristics of fresh concrete experimentally is not an easy task. In this study, considering the mixtures of materials that compose fresh concrete, rheological characteristics of fresh concrete such as slump, yield stress and viscosity values were determined theoretically at a high degree of accuracy by artificial neural networks (ANN) method. Consequently, it was concluded that using ANN in determining flow characteristics of fresh concrete would be a convenient and easy to use tool. © 2010 Inderscience Enterprises Ltd.Öğe Estimation of slump value and Bingham parameters of fresh concrete mixture composition with artificial neural network modelling(2011) Bilgil A.High performance is the most important expectation from concrete which is commonly used in today's construction technology. To form a high performance concrete "HPC", two fundamental properties are required. These properties are optimization of the materials used to form the concrete and the workability of fresh concrete during shaping. Many scientists have used rheological properties in conjunction with Bingham model to determine the workability of fresh concrete. Bingham model is represented by two parameters: yield stress and plastic viscosity. Even though, many models are developed to explain rheological properties, there is no acceptable easy to use method. In this study, artificial neural network "ANN" is used to determine the rheological properties of fresh concrete. Ferraris and de Larrard's experimental slump, yield stress and viscosity data from different composed concretes is used in this study. Slump, yield stress and viscosity are estimated with respect to mixture design parameters. Obtained results from this study indicates that ANN is a utilizable method to determine the rheological proporties (Bingham model) of fresh concrete. © 2011 Academic Journals.Öğe Investigation of availability of raw perlite in refractory building material production(International University of Sarajevo, 2018) Yeşilyurt E.; Şimşek O.; Bilgil A.Perlite having rich reserves in Turkey is basic industrial raw material in line with sustainable development objectives. In recent years due to the thermal insulation properties expanded perlite has attracted the attention of researchers. It is started to use in some construction areas. Binder material is used to shape in the manufacturing of refractory bricks. Desired material was sintered at high temperature. In this study, perlite between 75-600 µm particle size was subjected to heat treatment at different temperatures and investigated to use in refractory construction materials production. Perlite grains clinging to each other engage a smooth shape. Gypsum is used as an activator in different proportions to achieve this objective. The samples were subjected to heat treatment at 1050-1200 °C for 30 minutes. In the 5% gypsum mixture highest compressive strength at 1150 °C was calculated as 47 MPa. Unit volume weight is considered as 1.95 g/cm3, water absorption by weight is determined as 0.30%. Superficial abrasion loss was determined to be 20 mm. Degree of porosity is calculated as 15%. Compactness was found to be 85%. Furthermore in the results of experiment of freezing of the obtained products was not found any damage or any strength loss. © 2018 Ergün Yesilyurt, Osman Simsek, Ahmet Bilgil.Öğe Investigation of the friction coefficient in smooth open channel flows [Serbest Yuzeyli Puruzsuz Kanallarda Yuk Kayip Katsayisinin Incelenmesi](Scientific and Technical Research Council of Turkey, Ankara, Turkey, 2000) Bilgil A.In practical engineering, the friction coefficient formulations developed for circular pipes are usually assumed to be valid for open channels and used in derivation of mathematical formulation. However, with the advent of more accurate measurement devices, it is now clear that such formulations cannot be used in open channels without modifications. The phenomena such as free surface, different wet surfaces with irregular shear stresses and secondary flows, make open channel flows more complicated than circular pipe flows. A new formulation for the friction coefficient is developed depending on the Reynolds Number (Re) and W/h, which is the ratio of channel width to its height. It is found that there is a 10 % difference in the friction coefficient in circular pipe flow and open channel flow under the same conditions. The new correlation agrees satisfactorily with those in the literature. The relation between ? and Re in circular pipe flow is found to be deviate in open channel flows. In this research a formulation similar to the Blasius equation is proposed for rectangular channels.In practical engineering, the friction coefficient formulations developed for circular pipes are usually assumed to be valid for open channels and used in derivation of mathematical formulation. However, with the advent of more accurate measurement devices, it is now clear that such formulations cannot be used in open channels without modifications. The phenomena such as free surface, different wet surfaces with irregular shear stresses and secondary flows, make open channel flows more complicated than circular pipe flows. A new formulation for the friction coefficient is developed depending on the Reynolds Number (Re) and W/h, which is the ratio of channel width to its height. It is found that there is a 10% difference in the friction coefficient in circular pipe flow and open channel flow under the same conditions. The new correlation agrees satisfactorily with those in the literature. The relation between ? and Re in circular pipe flow is found to be deviate in open channel flows. In this research a formulation similar to the Blasius equation is proposed for rectangular channels.Öğe Physical and Mechanical Properties of Cemented Ash-Based Lightweight Building Materials with and without Pumice(Hindawi Limited, 2018) Dogan-Saglamtimur N.; Güven A.; Bilgil A.Pumice, cements (CEM I- and CEM II-type), waste fly and bottom ashes (IFA, GBA, and BBA) supplied from international companies were used to produce lightweight building materials, and physical-mechanical properties of these materials were determined. Axial compressive strength (ACS) values were found above the standards of 4 and 8 MPa (Bims Concrete (BC) 40 and 80 kgf/cm2 class) for cemented (CEM I) pumice-based samples. On the contrary, the ACS values of the pumice-based cemented (CEM II) samples could not be reached to these standards. Best ACS results (compatible with BC80) from these cemented lightweight material samples produced with the ashes were found in 50% mixing ratio as 10.6, 13.2, and 20.5 MPa for BBA + CEM I, GBA + CEM II, and IFA + CEM I, respectively, and produced with pumice were found as 8.4 MPa (same value) for GBA + pumice + CEM II (in 25% mixing ratio), BBA + pumice + CEM I (in 100% mixing ratio), and pumice + IFA + CEM I (in 100% mixing ratio), respectively. According to the results, cemented ash-based lightweight building material produced with and without pumice could widely be used for constructive purposes. As a result of this study, an important input to the ecosystem has been provided using waste ashes, whose storage constitutes a problem. © 2018 Neslihan Dogan-Saglamtimur et al.Öğe Producing of qualified oil and carbon black from waste tyres and pet bottles in a newly designed pyrolysis reactor(Springer Netherlands, 2019) Doğan-Sağlamtimur N.; Bilgil A.; Güven A.; Ötgün H.; Yıldırım E.D.; Arıcan B.Waste tyre and waste polyethylene terephthalate (PET) bottles are major environmental problems. In this study, by using newly designed simple and efficient pyrolysis reactor, a five-stage decomposition (200, 300, 400, 500 and 600 °C) and pre-condensation with cooler motor (- 20, - 10, 0, + 10 and + 20 °C) followed by a final condensation were applied to waste tyre and waste PET bottles. In the pyrolysis process, liquid (pyrolytic oil) and solid (carbon black) products were obtained from only waste tyres. Waste PET gasified in the decomposition steps, but pyrolytic oil could not be obtained because it tended to freeze during condensations. Intermediate temperature and cooling steps were tried by making an optimum design for the amount/efficiency of the pyrolytic oil obtained from waste tyre, and the combination giving the best result (about 50–60% for yield and 43.1 MJ kg -1 for the highest calorific value) was determined to be 500 °C and + 20 °C as decomposition and condensation temperatures, respectively. Compared to the literature, it was produced a highly productive pyrolytic oil at lower temperatures. The physical and chemical properties of this oil were in accordance with national and international standards in terms of the fundamental parameters. The net calorific value of the carbon black produced was in the range of 6337–7308 kcal kg -1 (26.5–30.6 MJ kg -1 ). © 2018, Akadémiai Kiadó, Budapest, Hungary.Öğe Reusability of ashes for the building sector to strengthen the sustainability of waste management(IGI Global, 2018) Doğan-Sağlamtimur N.; Bilgil A.; Öztürk B.Coal, as a fossil fuel, is used to generate power for industrial operation. Two types of industrial ash, including fly and bottom ash, which are solid residues arising from coal burning, are dumped to the landfill with no care for reuse. These wastes consist of environmental issues needing to be resolved. The ashes are used in the production of cement, concrete, aggregates, adobe, brick, and insulation material, in the construction of dam and road, and in geotechnical applications. Construction material is a form of cementitious materials based on ash as source material and it is an environmentally friendly choice against Portland cement releasing a large amount of greenhouse gas to the atmosphere during energy intensive manufacturing process. It is a good alternative to the solution of environmental problems based on the waste ashes in the international scale. In addition to its economic benefits, it is suitable for industrial symbiosis. This chapter explores the reusability of ashes for the building sector to strengthen the sustainability of waste management. © 2018, IGI Global.
