Browsing by Publisher "Polska Akademia Nauk"
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Item Neutron shielding properties of concrete and ferro-boron(Polska Akademia Nauk, 2015) Sariyer D.; Küçer R.; Küçer N.The problem of shielding against high-energy neutrons has always attracted a great deal of attention. Neutron shielding requires slowing down energetic neutrons and absorbing with a shield material. Concrete is one of the best known materials for neutron shielding and ferro-boron is described as an alternative shielding material in this study. FLUKA Monte Carlo simulation code was used for the application of shielding calculation. When the simulation results are compared, it is clear that ferro-boron is more effective in neutron shielding than the concrete.Item Aluminum Alloy Development for Wheel Production by Low Pressure Die Casting with New Generation Computational Materials Engineering Approaches(Polska Akademia Nauk, 2021) Yaǧci T.; Cöcen Ü.; Çulha O.Computational Materials Engineering (CME) is a high technological approach used to design and develop new materials including the physical, thermal and mechanical properties by combining materials models at multiple techniques. With the recent advances in technology, the importance of microstructural design in CME environments and the contribution that such an approach can make in the estimation of material properties in simulations are frequently discussed in scientific, academic, and industrial platforms. Determination of the raw material characteristics that can be modeled in a virtual environment at an atomic scale by means of simulation programs plays a big role in combining experimental and virtual worlds and creating digital twins of the production chain and the products. In this study, a new generation, alternative and effective approach that could be used to the development of Al-Si based wheel casting alloys is proposed. This approach is based on the procedure of optimizing the physical and thermodynamic alloy properties developed in a computer environment with the CME technique before the casting phase. This article demonstrates the applicability of this approach in alloy development studies to produce Al-Si alloy wheels using the low pressure die casting (LPDC) method. With this study, an alternative and economical way is presented to the alloy development studies by trial and error in the aluminum casting industry. In other respects, since the study is directly related to the automotive industry, the reduction in fuel consumption in vehicles is an expected effect, as the new alloy aims to reduce the weight of the wheels. In addition to conserving energy, reducing carbon emissions also highlights the environmental aspects of this study. © 2021 Polish Academy of Sciences. All rights reserved.Item Synthesis of natural phenolic compound contained alkaline phenolic foundry resin and its performance evaluation on casting(Polska Akademia Nauk, 2021) Güvendik A.E.; Ay K.In foundry, metal casting can be done with various methods. One of the most important methods preferred around the world is sand casting. Ester curable alkaline phenolic resins have produced to make sand molds by No-bake systems. They must have specific properties to make sand casting efficient and reliable. Production of these resins depends on some fossil raw-materials like phenol. To investigate more sustainable and green resin synthesis method, lots experiment have been done by substitution of phenol with renewable alternative phenolic materials like resorcinol, lignosulphonates and tannic acid and its derivatives. Different properties of resins were produced with competitive performance with the market product, ÇKE Alfanol A 72 No-Bake Resin. Without loss of performance, calcium lignosulfonate was used in polymer synthesis at the rate of 15% instead of phenol. On the other hand, the reaction in which lignin and resorcinol were combined instead of phenol by reducing it by 25% gave better results in terms of mechanical and thermal properties. Thermal properties were investigated for resorcinol and lignin modified resins by using TGA-DSC and mechanical performance of cured sand core sample were tested by Simpson Sand Strength Testing Machine as compression strength as N/cm2.. After laboratory testing casting performance of new resins are compared with two different companies’ resins in steal casting demo. Experimental results were matched with casting trail and no defect was detected. © 2021 Polish Academy of Sciences. All rights reserved.Item Effect of chip amount on microstructural and mechanical properties of a356 aluminum casting alloy(Polska Akademia Nauk, 2021) Kaya A.Y.; Ozaydin O.; Yagci T.; Korkmaz A.; Armakan E.; Culha O.Aluminum casting alloys are widely used in especially automotive, aerospace, and other industrial applications due to providing desired mechanical characteristics and their high specific strength properties. Along with the increase of application areas, the importance of recycling in aluminum alloys is also increasing. The amount of energy required for producing primary ingots is about ten times the amount of energy required for the production of recycled ingots. The large energy savings achieved by using the recycled ingots results in a significant reduction in the amount of greenhouse gas released to nature compared to primary ingot production. Production can be made by adding a certain amount of recycled ingot to the primary ingot so that the desired mechanical properties remain within the boundary conditions. In this study, by using the A356 alloy and chips with five different quantities (100% primary ingots, 30% recycled ingots + 70% primary ingots, 50% recycled ingots + 50% primary ingots, 70% recycled ingots + 30% primary ingots, 100% recycled ingots), the effect on mechanical properties has been examined and the maximum amount of chips that can be used in production has been determined. T6 heat treatment was applied to the samples obtained by the gravity casting method and the mechanical properties were compared depending on the amount of chips. Besides, microstructural examinations were carried out with optical microscopy techniques. As a result, it has been observed that while producing from primary ingots, adding 30% recycled ingot to the alloy composition improves the mechanical properties of the alloy such as yield strength and tensile strength to a certain extent. However, generally a downward pattern was observed with increasing recycled ingot amount. © 2021 Polish Academy of Sciences. All rights reserved.Item Complex Exponential Method for Solving Partial Differential Equations(Polska Akademia Nauk, 2024) Pakdemirli M.For constant-coefficient linear partial differential equations solvable by separation of variables, an alternative solution method is proposed. The method employs complex exponential functions to find exact analytical solutions. Examples include the heat conduction equation, homogenous and non-homogenous wave equations, and the beam vibration equation. The method can be effectively used for partial differential equations (PDEs) whose solutions can be expressed as a product of harmonic and/or exponential type series. © 2024 The Author(s).