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In order to simulate the wear behavior of materials subjected to solid particle erosion due to high temperature as well as velocity effect in operating conditions such as power plants and jet engines, ASTM G76 standard is not sufficient and test rig compliant with ASTM G211-14 standard must be put forward. In this context, a test rig, alternative to existing systems where solid particle erosion wear experiments can be performed in compliance with high temperature (~ 700 °C) and particle impact velocity (~ 150 m/s) conditions, has been designed and produced. In order to ensure the widespread us ...Daha fazlası
GÜLEÇ, Ali | ACAR, Mehmet Ali | AYDIN, Bahattin Kerem | DEMİR, Teyfik | ÖZKAYA, Mustafa
Supracondylar humerus fractures are common fractures around the elbow. Open fractures, comminuted metaphyseal fractures and also fractures with bone loss may need to be treated with external fixators. The aim of this study is to compare two different external fixators, tubular external fixators and polymethyl methacrylate with K wires external fixators, with regard to stiffness and stability for metaphyseal-diaphyseal osteotomies of distal humerus close to the joint. Six matched pairs (24 specimens) of second-generation sawbone humerus were prepared in a standard fashion to create a metaphysea ...Daha fazlası
Previously, Preheating has been established in micro-nozzles to increase the specific impulse of thrusters and increase thrust level. However, heating may cause higher viscous losses in micro-nozzles working at low Reynolds numbers. In this work, heating is combined with gas expansion by using heated walls for convergent-divergent micro-nozzle. The flow in 2D micro-nozzle with heat generation inside the side-walls has been numerically simulated and analyzed. A wide range of low Reynolds numbers flow is tested to investigate the effect of flow parameters. A range of diverse amounts of heat flux ...Daha fazlası
In this study, parametric optimization and sensitivity analysis of performance parameters were performed for the Organic Rankine Cycle (ORC) system at 120 °C heat source temperature. R1234ze, which is called the new-generation fluid, was used in the ORC design. Performance parameters have been selected considering Energy, Exergy, Economy (Turbine performance) and Environmental (Thermodynamic sustainability indices) factors. Six performance indices used in the orthogonal design with Taguchi-ANOVA. These are; thermal efficiency, turbine power, exergy efficiency, total irreversibility, Volume Flo ...Daha fazlası
HAMEED, Amar Hasan | MOHAMMED, Ahmed Abdullah | FADHIL, Obaid
Cooling heat flux effect in both primary and secondary cooling zone has been studied in semi-continuous casting of copper billet. Sufficient cooling is essential to reduce casting defects and to get high productivity, however low rate of solidification is aimed in order to get coarser grain size and softer metal for less losses in extrusion. A three-dimensional numerical model has been developed including solidification behavior of copper through mushy zone. At steady state and constant casting speed, solid shell thickness is monitored during the reduction of cooling rate at mould region to av ...Daha fazlası
BAĞCI, Mehmet | ŞÜKÜR, Emine Feyza | DEMİRCİ, Musa | KAYBAL, Halil Burak
During erosion tests of glass fibre/epoxy nanocomposites, an incubation period emerged because of the embedding of abrasive particles into the target material. In this study, the effect of this period on solid particle erosion behaviour was investigated for glass fibre/epoxy composites with the addition of nanoclay. The surface erosion characteristics of the composites were obtained by solid particle erosion tests using angular alumina particles with a size on the order of 400 μm as the erodent. The tests were conducted using impact velocities of ~23 or ~34 m/s and impingement angles of 30°, 6 ...Daha fazlası
Inconel 718 altlık malzeme üzerine iki farklı bağ kaplama (NiCrAlY ve NiCoCrAlY), Atmosferik Plazma Sprey (APS) ve Yüksek Hızlı Oksi-Yakıt Püskürtme (HVOF) yöntemleri kullanılarak uygulanmıştır. Enerji dönüşüm santralleri, gaz türbinleri, jet motor kanatları vb. uygulamalarda kullanılan bağ kaplamaların yüksek sıcaklık altında partikül etkisine maruz kalmasının simüle edilmesi amaçlanmıştır. Kaplama işlemi sonunda farklı özelliklere sahip dört numune grubu oluşturulmuştur. Bu numunelerin ortam koşulları ve sıcaklık altında katı partikül erozyon aşınma davranışları incelenmiştir. Deneylerde, yü ...Daha fazlası
The erosion wear of the thermal barrier coating (TBC) application created by the ceramic topcoat effect on the substrate material and the high-temperature resistance has been researched in the study. Solid particle erosion effect has an important role in high-temperature applications such as energy conversion plants, gas turbines, and jet engine blades. In these applications where the ambient temperature varies and high-temperature effect is important, the deformation resistance is an important criterion in TBC’s produced with atmospheric plasma spray (APS) and high-velocity oxy fuel (HVOF) me ...Daha fazlası
Bu çalışmada, Organik Rankine Çevrimi (ORÇ) üzerinde etkisi olan performans parametrelerinin hassasiyet seviyeleri ve katkı oranları belirlenmiştir. Performans parametreleri evaporatör-kondenser pinch point sıcaklık farkı (∆TPP,e, ∆TPP,k), soğutma suyu giriş sıcaklığı (Tc,i), aşırı kızdırma sıcaklığı (Tak), türbin-pompa izantropik verimleri (ƞt ve ƞp) olarak seçilmiştir. Bu parametrelerin ORÇ sistemi üzerindeki etkisi farklı amaç fonksiyonları altında değerlendirilmiştir. İncelenen amaç fonksiyonları; ısıl verim, net güç ve ekserji verimi maksimizasyonu ile toplam tersinmezlik, hacimsel debi o ...Daha fazlası
Carbon fiber–reinforced polymers (CFRPs) are often exposed to solid particle erosion wear due to small particles moving freely in the atmosphere or in the environment and their impact on aircraft bodies. In this study, fiber weaves of CFRP composite materials of the following types were produced: unidirectional (U), plain weave multidirectional (P), and twill 2 × 2 weave multidirectional (T). Tests that involved three different CFRP composite materials were conducted at room temperature with two groups (pure and exposed to cryogenic liquid nitrogen treatment), at two different fiber directions ...Daha fazlası
ULUDAĞ, Muhammet | ÇETİN, Remzi | DIŞPINAR, Derya | TİRYAKİOĞLU, Murat
The effect of melt quality on hot tearing susceptibility of Al8Si3Cu alloy was examined under six different conditions, by using a traditional T-shaped mold. Grain refinement was carried out by two different modifiers: AlTi5B1 and Al3B. For each test, samples were cast before and after degassing of melt. Therefore, a new hot tearing tendency index was developed by both bifilm calculations and porosity that occurred in the middle of T-zone of casting parts. Results indicated that hot tearing of cast aluminum alloys was a complex phenomenon, and bifilms play a major role, especially by compensat ...Daha fazlası
ÇETİN, Remzi | ULUDAĞ, Muhammet | KOÇABAŞ, Mustafa | DIŞPINAR, Derya | CANSEVER, Nurhan
In the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed. In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion test, the Ecorr values for all conditions were determined approx ...Daha fazlası
6698 sayılı Kişisel Verilerin Korunması Kanunu kapsamında yükümlülüklerimiz ve cerez politikamız hakkında bilgi sahibi olmak için alttaki bağlantıyı kullanabilirsiniz.