Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Subject: search.filters.subject.Aluminum

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Now showing 1 - 4 of 4
  • Master Thesis
    The Effect of Material Strain Rate Sensitivity on the Shock Deformation of an Aluminum Corrugated Core
    (Izmir Institute of Technology, 2018) Canbaz, İlker; Güden, Mustafa; Taşdemirci, Alper
    The effect of the material model on the crushing behavior of a layered 1050 H14 aluminum corrugated sandwich structure was investigated numerically as function of velocity (0.0048, 20, 60, 150 and 250 m s-1) using three different material models; elastic-perfectly plastic (model I), elastic-strain hardening (model II) and elastic-strain and strain rate hardening (model III). Three-dimensional finite element models were developed in the explicit finite element code of LS-DYNA. Between 0.0048 m s-1 and 20 m s-1, the numerically calculated stresses at the impact and distal end were almost the same and in equilibrium, showing a “quasi-static homogenous mode”. The deformation mode at 60 m s-1 was a “transition mode” and between 150 and 250 m s-1 a shock mode in which the layers were crushed sequentially. The numerical study showed that the strain and strain rate hardening models tended to induce non-sequential layer crushing. The collective layer crushing was also more pronounced in the material model II and III than the material model I. For low strain hardening aluminum alloys and similar materials, the effect of strain hardening in increasing plateau stress was more significant than the strain rate hardening at the quasi-static velocity, while both strain hardening and strain rate hardening effect increased with increasing velocity. The stress reduction by the inclusion of imperfections however declined with the velocity since the samples started to deform near the impact end as the velocity increased.
  • Master Thesis
    Adsorption Kinetics of Methane Reformer Off-Gases on Aluminum Based Metal-Organic Frameworks
    (Izmir Institute of Technology, 2017) Angı, Deniz; Çakıcıoğlu Özkan, Seher Fehime
    Over the last decades, with the development in industrialization, the combustion of fossil fuels has generated an increasing level of emission of greenhouse gases into atmosphere. Considerable efforts have been endeavored to advance alternative cleaner energy source to relieve the stress on environmental concerns and depletion of oil reserves. Hydrogen is regarded as an ideal clean energy carrier. A great majority of ultrapure hydrogen is produced by hydrogen rich steam methane reformer (SMR) off-gas mainly composed of 60-80% H2, 15-25% CO2, 3-6% CH4 and 1-3% CO, which severely requires an efficient separation and purification process associated with gas adsorption principle. A novel class of porous adsorbents known as metal-organic frameworks (MOFs) represent outstanding separation performance due to possessing large surface area and tunable pore size. Aluminum based metal organic frameworks (Al-TPA) are widely utilized in gas separation/purification applications due to its breathing characteristics by adjusting cell volume reversibly. The highest surface area of Al-TPA was found to be 1270 m2/g by performing solvothermal synthesis route. Diffusion studies of SMR off-gas components on the Al-TPA were carried out at different flow rates (80, 168 and 175 mL/min), temperatures (34, 70 and 100 °C) and concentrations (15 and 28%). High value of parameter L demonstrated that system was under kinetic control. The diffusivity values were found to be ranging from 5.73 x 10-13-8.04 x 10-13 for CO2, 5.03 x 10-13-6.64 x 10-13 for CH4, 1.36 x 10-12-1.56 x 10-12 for H2 and 1.01 x 10-13- 5.03 x 10-13 m2/g for CO respectively with increasing temperature.
  • Master Thesis
    Catalytic Surface Coatings for Household Ovens
    (Izmir Institute of Technology, 2016) İzer, Alaz; Şeker, Erol; Şeker, Erol
    The emission of harmful volatile compounds, such as aldehydes, and also carbon monoxide could occur during cooking processes at home or industry due to the combustion and cracking of spilled vegetable oil on the walls of an oven. It is known that the by-products generated during cooking could affect human health and environment if they are properly vented or removed. To eliminate the health and environmental problems related to oven emission, self-cleaning catalytic materials coated walls for ovens seem to be viable alternative to the toxic and time consuming chemical cleaning solutions. In this project, a sol-gel method and also the dip coating technique was used to produce a catalytic material coated aluminum plates. Specifically, the calcination time and the temperature were studied to better understand the relationship between the textural/chemical properties of the catalyst coated metal plates and their catalytic activities. The studied calcination temperatures were 450°C, 500°C and 550°C whereas the calcination time were 10 min, 30 min and 60 min for each type of catalyst. Aluminum oxide supported nickel and also aluminum oxide - manganese oxide supported nickel catalysts were prepared as the catalyst that were used in coating. The catalytic activities of the catalyst coated plates were determined using canola oil as a function of reaction time which were 1h at 170°C and 200°C. The results have been shown that the most convenient calcination conditions for the canola oil combustion were 500°C for 30 minutes by using aluminum oxide – manganese oxide supported nickel catalyst.
  • Master Thesis
    Joining and Interfacial Properties of Aluminum/Glass Fiber Reinforced Polypropylene Sandwich Composites
    (Izmir Institute of Technology, 2009) Guruşçu, Aslı; Tanoğlu, Metin
    The joining of separate components using a suitable technique is a critical step in the manufacture of composite structures. For good property performance of aluminum/glass fiber reinforced polypropylene (Al/GFPP) laminates, one of the most important problems is to obtain good adhesive bond strength.In the present study, Al/GFPP laminates have been manufactured with various surface pretreatment techniques. Adhesion at the composite/metal interface has been achieved by surface pretreatment of Al with amino based silane coupling agent, incorporation of polyolefin based adhesive film and modification with PP based film containing 20 wt. % a maleic anhydride modified polypropylene (PP-g-MA). The mechanical properties shear, peel and bending strength of the adhesively bonded Al/GFPP laminates were investigated to evaluate the effects of those various surface treatments. In addition, peel strengths of Al foam/GFPP laminates with various surface treatments were measured. The fracture surfaces have been examined by scanning electron microscope (SEM). Results showed that the adhesion of the laminated Al/GFPP systems were improved by treatment of aluminum surfaces with amino-based silane coupling agent. Based on peel and bending strength results, Al/GFPP laminates with incorporation of polyolefin based adhesive films exhibited significant increase on the adhesive behaviour. Modification of Al/GFPP interfaces with PP-g-MA layer leads to highest improvement on the adhesion properties.