The Investigation Of An Air Breathing Rocket Engine Powered Vehicle

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2003Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2003Bu tez çalışması kapsamında, örnek bir taşıtın havayla çalışan bir roket motoruyla tahriği incelenmiştir. Roket motorundan elde edilecek tepki kuvvetinin bu taşıtın belli bir sabit hızında, üzerine etki eden seyir dirençlerini dengeleyen kuvvet olduğu düşünülmektedir. Bu bakımdan taşıtın öngörülen hareketi esnasındaki seyir dirençlerinin hesaplanmasıyla, roket motorundan alınması hedeflenen tepki kuvveti bulunmuştur. Bu hesabın değişik hız değerleri için yapılmasından sonra, elde edilen tepki kuvvetlerini makul miktarda yakıcı ve yakıt debisiyle sağlayan sistemdeki lüle, yanma odası ve püskürtme sisteminin tasarımı yapılmıştır. Yapılan bu tasarım birçok faktöre bağlı olarak değiştiğinden, tanımlanan roket motoru karakteristik parametreleri yardımıyla, değişen işletme koşullarının tasarlanılan sisteme ne gibi etkiler yaptığı araştırılmıştır. Bu çalışmada yanma odası basınçları ile yakıcı ve yakıt olarak kullanılan hava ve kerozen arasındaki yanma reaksiyonunda karışım oranını tanımlayan hava fazlalık katsayıları değiştirilerek elde edilmesi hedeflenen tepki kuvvetine göre tasarımı yapılan roket motorundaki lüle boğaz ve çıkış kesit alanları, yanma odası uzunluğu ve gerekli yakıcı ve yakıt debisi gibi büyüklüklerin bu değişimlerden ne şekilde etkilendiği incelenmiştir. Çalışmanın son bölümünde ise yapılan tasarıma uygun bir püskürtme sisteminin geliştirilmesi amaçlanmıştır. Hava ile kerozenin yanma reaksiyonları ve yanma odasına giriş hızları dikkate alınmak suretiyle, taşıt hızlarına göre hesaplanan tepki kuvvetini sağlayan yakıcı ve yakıt debisini, tasarımı yapılan roket motoruna sevk edecek püskürtme sistemi büyüklükleri hesaplanmıştır. Ayrıca bu büyüklüklerin değişen koşullardan ne şekilde etkilendiği oluşturulan tablo ve grafikler yardımıyla belirtilmiştir.In this study, the propulsion of an air breathing rocket engine powered vehicle is investigated. The thrust for this rocket engine is assumed to be the force which can overcome the total resistance forces acting on this vehicle for a chosen constant speed. So, the calculation of the total resistance forces acting on the vehicle, under the conditions of constant speed and normal road conditions, leads us to determine the thrust of the rocket engine. After finding the necessary thrust for the constant speed of vehicle, rocket nozzle, combustion chamber and injection system designs are made to obtain that thrust. As the design of the rocket engine for obtaining desirable thrust relies on various factors, it is convenient to make use of characteristic parameters to examine the changes occurred in our design resulting from these factors. In this study the changes in the nozzle throat and exit areas, combustion chamber lenghts and necessary mass flow rate values used in the air breathing engine, are investigated by changing the combustion chamber pressures and air excess ratios which define the mixture ratio of the propellant. In the last chapter of this study, it is intended to design an appropriate injection system for the air breathing rocket engine. By considering the speeds of air and kerosene in the combustion chamber and the mechanism of combustion reaction, injection system dimensions are calculated. The changes of injection system characteristic parameters versus design conditions are shown in the graphics plotted in this study.Yüksek LisansM.Sc

Amine-Functionalized Polylactide–PEG Copolymers

The formation of halogenated carboxylic acid intermediate followed by a ring-closing reaction led to amino-functionalized asymmetrical lactide monomer. PEG-based functional diblock and triblock polylactides were synthesized via a controlled ring-opening polymerization in a solvent-free medium with high conversions (up to 96%), low polydispersities as low as 1.06, monomodal GPC traces, and short reaction time (only 1 h). No polymerization of symmetrical monomer, synthesized via condensation of (<i>S</i>)-(+)-CBZ-4-amino-2-hydroxybutyric acid, proved that the preferred site in the mechanism of ring-opening polymerization was found as a methyl site in asymmetrical lactide monomer. A highly efficient deprotection of copolymers was carried out in the presence of H₂ gas and Pd/C catalyst without any degradation to obtain the corresponding free amine-functionalized aliphatic poly­(α-hydroxy acid)­s. These biodegradable thermosensitive polymers, suitable for any local therapy applications, were injectable around 42 °C (sol) and a gel just after cooling to body temperature. Faster hydrolytic degradation (up to 47% in 30 days) and more effective paclitaxel release from copolymer gels (up to 95% in 20 days) than well-known conventional PEG–PLA gels may make functional lactides a preferred candidate for developing controlled/sustained release of drugs from delivery vehicles

The Definition of Sarcomeric and Non-Sarcomeric Gene Mutations in Hypertrophic Cardiomyopathy Patients: A Multicenter Diagnostic Study Across Türkiye

Background: Hypertrophic cardiomyopathy is a common genetic heart disease and up to 40%-60% of patients have mutations in cardiac sarcomere protein genes. This genetic diagnosis study aimed to detect pathogenic or likely pathogenic sarcomeric and non-sarcomeric gene mutations and to confirm a final molecular diagnosis in patients diagnosed with hypertrophic cardiomyopathy. Methods: A total of 392 patients with hypertrophic cardiomyopathy were included in this nationwide multicenter study conducted at 23 centers across Türkiye. All samples were analyzed with a 17-gene hypertrophic cardiomyopathy panel using next-generation sequencing technology. The gene panel includes ACTC1, DES, FLNC, GLA, LAMP2, MYBPC3, MYH7, MYL2, MYL3, PLN, PRKAG2, PTPN11, TNNC1, TNNI3, TNNT2, TPM1, and TTR genes. Results: The next-generation sequencing panel identified positive genetic variants (variants of unknown significance, likely pathogenic or pathogenic) in 12 genes for 121 of 392 samples, including sarcomeric gene mutations in 30.4% (119/392) of samples tested, galactosidase alpha variants in 0.5% (2/392) of samples and TTR variant in 0.025% (1/392). The likely pathogenic or pathogenic variants identified in 69 (57.0%) of 121 positive samples yielded a confirmed molecular diagnosis. The diagnostic yield was 17.1% (15.8% for hypertrophic cardiomyopathy variants) for hypertrophic cardiomyopathy and hypertrophic cardiomyopathy phenocopies and 0.5% for Fabry disease. Conclusions: Our study showed that the distribution of genetic mutations, the prevalence of Fabry disease, and TTR amyloidosis in the Turkish population diagnosed with hypertrophic cardiomyopathy were similar to the other populations, but the percentage of sarcomeric gene mutations was slightly lower