Experimental Study and Numerical Simulation of Methane Oxygen Combustion inside a Low Pressure Rocket Motor

In this thesis, combustion processes in a laboratory-scale methane based low pressure rocket motor (LPRM) is studied experimentally and numerically. Experiments are conducted to measure flame temperatures and chamber temperature and pressure. Single reaction-four species reacting flow of gaseous methane and gaseous oxygen in the combustion chamber is also simulated numerically using a commercial CFD solver based on 2-D, steady-state, viscous, turbulent and compressible flow assumptions. LPRM geometry is simplified to several configurations, i.e. Channel and Combustion Chamber with Nozzle and FWD. Flow in a Bunsen burner is simulated inside Channel geometry in order to validate the reaction model. Grid independence study is also conducted for reacting as well as non-reacting flows. Numerical model is calibrated based on experimental results. Results of the computational model are found in a good agreement with the experimental data after calibrating specific heats of the products. Parametric study is conducted in order to investigate the effects of different mass flow rates and chamber pressures on flow and combustion characteristics of a LPRM to provide insight to future studies

Experimental Study and Numerical Simulation of Methane Oxygen Combustion inside a Low Pressure Rocket Motor

In this thesis, combustion processes in a laboratory-scale methane based low pressure rocket motor (LPRM) is studied experimentally and numerically. Experiments are conducted to measure flame temperatures and chamber temperature and pressure. Single reaction-four species reacting flow of gaseous methane and gaseous oxygen in the combustion chamber is also simulated numerically using a commercial CFD solver based on 2-D, steady-state, viscous, turbulent and compressible flow assumptions. LPRM geometry is simplified to several configurations, i.e. Channel and Combustion Chamber with Nozzle and FWD. Flow in a Bunsen burner is simulated inside Channel geometry in order to validate the reaction model. Grid independence study is also conducted for reacting as well as non-reacting flows. Numerical model is calibrated based on experimental results. Results of the computational model are found in a good agreement with the experimental data after calibrating specific heats of the products. Parametric study is conducted in order to investigate the effects of different mass flow rates and chamber pressures on flow and combustion characteristics of a LPRM to provide insight to future studies

Characterization and Optimization of Radiation at Nano Scale: Applications in Solar Cell Design

High energy needs and environmental concerns associated with fossil fuels have raised the demand for efficient and clean alternatives of power generation. Solar cell technology is one of the most promising options of reliable renewable power sources despite high costs. Thin film solar cells offer the potential for reduction in the cost per kilowatt-hour due to the lower material usage. Nevertheless, most thin film solar cells suffer from low efficiency, though advancements in the science of near field radiation have led to substantial improvements in their optical efficiency. Many design challenges remain to be overcome for the wide-scale commercialization of thin film solar cells. In this dissertation, a numerical study is conducted for optical, optoelectrical and scattering performance enhancement of subwavelength optical devices (i.e., thin film solar cells and light trapping nanoparticles). The proposed design framework of thin film solar cells is based on learning based optimization and characterization methods, which utilize approximations of time consuming simulations. Additionally, a free form nanoparticle design procedure using evolutionary shape optimization is detailed. The background of thin film solar cells and a comprehensive literature review of the thin film solar cell design approaches are provided in Chapters 2 and 3, respectively. The optical enhancement of thin film solar cells using nanoparticles with different shapes is studied in Chapter 4. In Chapter 5, an approximate formulation for optoelectrical efficiency of thin film solar cells is developed to accelerate the design optimization. The learning based design methodology that is introduced in Chapter 5 is further improved in Chapter 6 using a knowledge transfer concept (also known as transfer learning). In this chapter, multiple sets of material combinations are optimized and compared with each other in terms of their optoelectrical efficiencies. In Chapter 7, nanoparticles are designed for maximum scattering, which is desired for enhanced optical performance, using a nonparametric evolutionary design method. In Chapter 8, a predictive model for scattering of arbitrarily shaped nanoparticles using descriptive geometric features is proposed. Overall, this dissertation has led to significant contributions in the field of thin film solar cell design. The results show that the computational burden of the thin film solar cell design can be overcome significantly without sacrificing accuracy. Furthermore, the design methods developed for this dissertation can easily be transferred to other engineering areas involving repetitive, time consuming simulations for design optimization, such as other photonic design problems and integrated circuit design

Allium sphaeronixum (Amaryllidaceae), A New Species from Turkey

n this paper, Allium sphaeronixum, a new species of the sect. Codonoprasum from Turkey, is described and illustrated. The new species is endemic to Central Anatolia, limited to the area of Nevşehir, where it grows on sandy or rocky soil at an elevation of 1000–1300 m a.s.l. Its morphology, phenology, karyology, leaf anatomy, seed testa micromorphology, chorology, and conservation status are examined in detail. The taxonomic relationships with the closest allied species, A. staticiforme and A. myrianthum, are also highlighted and discussed

TEKİRDAĞ BÖLGESİ YÜZEYEL MANTAR ENFEKSİYON ETKENLERİNİN FARKLI YÖNTEMLERLE İDENTİFİKASYONU VE ANTİFUNGAL DUYARLILIĞI

Yüzeyel mikozlar, dünyanın her tarafında yaygın olarak görülmekte olup, ekolojik koşullara bağlı olarak değişen izolasyon sıklığı bildirilmektedir. Çalışmamızın amacı; Tekirdağ bölgesinde yüzeyel mikozlarda en sık etken olan dermatofit ve mayaların araştırılması ve izolatların sık kullanılan antifungal ajanlardan mikonazol, itrakonazol, terbinafin ve nistatin’ e karşı yanıtlarının antifungal duyarlılık testiyle belirlenmesidir. Çalışmamızda; 11.10.2011-08.04.2013 tarihleri arasında Namık Kemal Üniversitesi Sağlık Uygulama ve Araştırma Merkezi Deri ve Zührevi Hastalıklar Kliniğinden Mikrobiyoloji Laboratuvarına gönderilen 726 hastaya ait toplam 898 örnek geleneksel yöntemler ile incelenmiş ve yüzeyel mikoz etkeni olarak belirlenen 159 izolatın, identifikasyonu önce geleneksel daha sonra moleküler yöntemlerle yapılmıştır. Yüzeyel mikoz sıklığı %17,7 olarak saptanmıştır. Üreme saptanan örneklerin 100 (%62.9)’ ü dermatofit ve 59 (%37.1)’ u maya olarak tanımlanmıştır. Hastalardan alınan örneklerin enfeksiyon bölgelerine göre dağılımına bakıldığında; en sık karşılaşılan klinik tablo sırasıyla tinea pedis (n=476, %53) ve tinea unguium (n=321, %35.74) olmuştur. İzole edilen dermatofitler; T. rubrum (%66), T. mentagrophytes (%15), M. canis (%8), T. tonsurans (%4), T. verrucosum (%3), E. floccosum (%3) ve T. terrestre (%1)’ dir. Maya izolatlarının tanımlamalarına bakıldığında; %31’ si C. glabrata, %15.25’ si C. guillermondii, %11.86’ sı C. albicans, %6.77’ si C. tropicalis, %3.38’ i C. dubliniensis, %1.69’u C. keyfr, %1.69’u C. krusei, %1.69’u C. lusitaniae, %1.69’u C. parapsilosis, %1.69’u C. zeylanoides, %1.69’u Rhodotorula sp. olarak saptanmıştır. Antifungal duyarlılık düzeylerine bakıldığında; T. rubrum suşlarının T. mentagrophytes suşlarına göre minimal inhibisyon konsantrasyonlarının (MİK) daha yüksek olduğu görülmüştür. Türler arasında en düşük MİK değerleri T. verrucosum ve T.terrestre suşlarında görülmüştür. Mayaların çeşitli antifungallere karşı duyarlılıkları incelendiğinde izolatların mikonazol, itrakonazol ve terbinafin’ e direnç geliştirdiği görülmüştür. Nistatine karşı daha az direnç saptanmıştır.Superficial mycoses, a worldwide infection shows different isolation rates due to ecological factors.The aim of our study was to detect the common causes of superficial mycoses in Tekirdağ region and antifungal susceptibilities of the isolates to miconazole, itraconazole,terbinafin and nystatine. A total of 898 samples of 726 patients which were sent to Microbiology laboratory from the Clinics of Dermatology of Namık Kemal University Hospital, between 11.10.2011 and 08.04.2013 were primarly examined with classical mycological methods, followed by molecular and classical identification methods of 159 agents of superficial mycoses. The frequency of superficial mycoses was 17.7%. Of the isolates, 100(62.9%) were dermatophytes and 59(37.1%) were yeasts. The most common clinical appearence were; tinea pedis(n=476, 53%) and tinea unguium (n=321, 35.74 %). The dermatophyte isolates were; T. rubrum (66%), T. mentagrophytes (15%), M. canis (8%), T. tonsurans (4%), T. verrucosum (3%), E. floccosum (3%) and T. terrestre (1%).The yeasts isolates were; C. glabrata (31%), C. guillermondii (15.25%), C. albicans (11.86%), C. tropicalis (6.77%), C. dubliniensis (3.38%), C. keyfr (1.69%), C. krusei (1.69%), C. lusitaniae (1.69%), C. parapsilosis (1.69%), C. zeylanoides (1.69%), Rhodotorula spp. (1.69%) respectively. As a result of susceptibility tests; MIC of T.rubrum were found higher than T. mentagrophytes isolates. The lowest MIC values were detected with T. verrucosum and T.terrestre. Resistance to miconazole, itraconazole and terbinafin was higher, whereas low resistance rates were detected to nystatine

Ga-67 Uptake in a Patient with Breast Cancer

Omurgasızlardan omurgalılara kadar evrimsel olarak oldukça korunan Wnt/β-katenin sinyal yolu hem erken embriyonik gelişimin düzenlenmesinde, hem de erişkin dokularda apoptozis, adipogenez, anjiogenez, sinaps oluşumu gibi olaylarda rol almaktadır. Bununla birlikte bu sinyal yolunda meydana gelen bozuklukların kanser başta olmak üzere birçok ciddi hastalığın etiyolojisinde rolü olduğunun düşünülmesi, son yıllarda bu sinyal yolu ile ilgili araştırmaları oldukça arttırmıştır. Wnt/β-katenin sinyal yolunun bu hastalıklardaki rolünü belirlemeye yönelik çalışmalarda çoğunlukla β-katenin, Axin, Adenomatöz polipozis koli (APC) gibi biyomoleküller araştırılmaktadır. Ayrıca, bu biyomoleküller sadece hastalıkların oluşum mekanizmalarının belirlenmesinde değil, bu hastalıkların tedavisinde hedef olarak da kullanılmaktadırlar. Dolayısıyla Wnt/β-katenin sinyal yolunun en önemli basamağı olan sitoplazmik reaksiyonların ve bu reaksiyonlarda görev alan biyomoleküllerin ortaya konulması sinyal yolunun bütünün tam olarak anlaşılması için oldukça önemlidir. Bu sebeple derlememizde hedef hücre sitoplazmasında görev yapan biyomoleküllerin tartışılması ve bu şekilde sinyal yolunun tam olarak aydınlatılması amaçlanmıştır. Wnt/β-catenin signaling pathway, which is highly evolutionarily conserved from invertebrates to vertebrates, regulates apoptosis, adipogenesis, angiogenesis, synapse formation in adult tissues, and controls embryonic development in the embryo. Researches related to the signal pathway because of its probable role in the etiology of serious diseases such as cancer are quite increased. In the studies, for determining the role of Wnt/β-catenin signaling pathway in these diseases, are mostly investigated biomolecules such as β-catenin, Axin, Adenomatous polyposis coli (APC). In addition, these biomolecules are not only used in determining the mechanisms of diseases, but also used as a target for treatment. Thus, determination of the cytoplasmic reactions, which are the most important step of the Wnt/beta-catenin signaling pathway, and biomolecules of these reactions are very important for understanding of fully signaling mechanism. Therefore, discussion of biomolecules in the cytoplasm of target cells and identification of the entire mechanism of the signaling pathway were aimed in our review

Evaluation of legislation about microbiologic examination in food handlers

Amaç: Çalışmamızın amacı, gıda alanında çalışanlarda portör muayenelerini düzenleyen mevzuatın incelenmesidir. Gereç ve Yöntem: Gıda alanında çalışanlar ile ilgili mevzuat metinleri, ulusal ve uluslararası literatür tarandı. Mevzuat ve internet üzerinden ulaşılabilen bilgi ve bulgular, bilimsel kanıtlar temelinde değerlendirildi. Konuyla ilgili mevzuat metinlerinin bilimsel kanıtlar ile değerlendirildiği, görüş ve önerilerin sunulduğu bir çalışmadır. Bulgular: Konuyla ilgili temel mevzuat Umumi Hıfzıssıhha Kanunu'dur(UHK). Sağlık Bakanlığı 2005 yılında bir genelge ile tetkikleri ve süreleri yeniden belirlemiştir. Portör muayenesi uygulamaları süregelirken; çıkartılan 663 sayılı Kanun Hükmünde Kararname(KHK)'de gıda ile uğraşan işyerlerinde hijyen uygulamaları ve eğitime önem verilmesi vurgulanarak sorumluluk işverene bırakılmıştır. Gıda kaynaklı infeksiyonlara neden olacak çok sayıda patojen mikroorganizma olmasına karşın yasal düzenlemeler, rutinde bu ajanların küçük bir kısmını incelememize olanak tanımaktadır. Güncel bilimsel yaklaşımlar, gıda çalışanlarında rutin tıbbi ve mikrobiyolojik incelemelerin yapılmasını önermemektedir. Son çıkan KHK'nin uygulanmasında sorun yaşanabileceği ve tamamlayıcı alt mevzuat düzenlemelerine gereksinim olduğu belirlenmiştir. Sonuç: Gıda hazırlama prosedüründe standardizasyon ve kontrol programlarının geliştirilmesi, hijyen eğitimleri verilmesi, erken uyarı sistemlerini kurulması ve belirti gösteren çalışanlara rutin tarama testlerinin uygulanması ile gıda kaynaklı infeksiyonların azaltılmasının sağlanması temel önerimizdir. Bu amaçla karar vericilerin, güncel bilimsel çalışma sonuçlarını dikkate alarak ivedilikle tamamlayıcı mevzuat çalışmalarına başlaması gerekmektedir.Introduction and Objective: Our study was planned to evaluate the Turkish legislation about microbiologic examination in foodhandlers. Material and Methods: National and international literature about legal regulations regarding foodhandlers in Turkey, were scanned. Legislation about microbiologic examination in foodhandlers and all documents were evaluated based on scientific evidence. This paper was designed to present the opinions and suggestions about this subject by evaluating the legislative texts on scientific evidence. Results: The main legislation is Law of Public Health. In 2005, Ministry of Health had made a circular and modified the analysis for food handlers and their frequency. While the applications of porter examination continues, by the decree law numbered 663 -indicating the importance of education and sanitation- this responsibility was given to the employers. Despite the presence ofvarious pathogenic microorganisms causing foodborne infections, the legal arrangements in our country allows the detection of only a small portion of these agents, by routine analysis. Current scientific approaches do not recommend routine medical and laboratory examination in food handlers. As some problems in daily practice can occur, last decree law about food handlers needs collateral legislation urgently. Conclusion: Our main recommendations are; to standardize the food preparation process, to give in training education, to establish early detection systems and to examine the routine laboratory analysis in symptomatic food handlers, to reduce the food borne infections. For this purpose, the governors have to start to work on complimentary legislation, considering the results of current scientific studies, urgently

Neutrophil gelatinase-associated lipocalin serum level: A potential noninvasive biomarker of endometriosis?

Neutrophil gelatinase-associated lipocalin (NGAL, also known as lipocalin-2) is an acute-phase protein expressed in many tissues and plays a role in cell proliferation, regulation, and epithelial-mesenchymal transformation. Therefore, this study aimed to investigate serum NGAL levels and endometrioma tissue expression in women with endometriosis. This cross-sectional study was conducted at a university hospital. The endometrioma group included 36 women who underwent ovarian cystectomy for endometrioma, which was compared with a control group (n = 36) of women who underwent ovarian cystectomy due to benign persistent cysts (follicle cyst, theca lutein cyst, and serous cystadenoma). NGAL levels were analyzed using both serum enzyme-linked immunosorbent assay analysis and immunohistochemical tissue staining. Serum C-reactive protein and CA-125 levels were also evaluated. NGAL serum levels were significantly higher in the endometrioma group than in the control group (P < .05). C-reactive protein and CA-125 levels were also significantly higher in the endometrioma group (P < .05) and were correlated with NGAL levels. Immunohistochemical staining for NGAL was also higher in the endometrioma group (P < .001). NGAL may be considered a potential noninvasive biomarker of endometriosis

Tekirdağ devlet hastanesi'ne başvuran gastroenteritli çocuklarda rotavirus ve adenovirus antijen varlığının araştırılması

Amaç: Çocuklarda infeksiyöz diyarenin sık etkenleri olan viral ajanların epidemiyolojisi ile ilgili bilgiler sınır- lıdır. Bu çalışmada Tekirdağ yöresinde rotavirus ve adenovirusa bağlı olarak gelişen gastroenteritlerin sıklığının araştırılması amaçlanmıştır. Gereç ve Yöntemler: Akut gastroenteritli çocukların dışkı örnekleri toplanmış ve Grup A rotavirus ve ade- novirus serotip 40-41 antijenleri açısından immunok- romatografik test (RIDA Quick, R-Biopharm, Almanya) ile taranmıştır. Sonuçlar yaşa dayalı gruplara ayrılarak değerlendirilmiştir. Buna göre gruplar; Grup A (0 - 2 yaş), Grup B (3-6 yaş) ve Grup C (7-15 yaş) şeklinde oluşturulmuştur. Bulgular: Dışkı örneklerinden 2135i rotavirus ve 2117si adenovirus varlığı açısından test edilmiştir. Örneklerden 222 (%10,4)sinde rotavirus ve 77 (%3,6)sinde adenovirus antijeni pozitif bulunmuştur. Tüm rotavirus pozitif olguların gruplara dağılımı ince- lendiğinde; Grup A, B ve Cde sırasıyla %63,7, %27,8, %8,5 (p<0,001) ve tüm adenovirus pozitif olguların gruplara dağılımı incelendiğinde ise Grup A, B ve Cde sırasıyla %40,3, %36,3, %23,4 (p=0,16) olarak bulunmuştur. Cinsiyetle ilişkili olarak her iki ajan açısından da anlamlı farklılık saptanmamıştır (p=0,38, p=0,31). Mevsimsel özellikler incelendiğinde rotavirus aralık ayında (n=44, %19,8), adenovirus ise temmuz ayında (n=21, %27,3) en sık olarak saptan- mıştır. Sonuç: Bulgularımız, rutin laboratuarlarda, infeksiyöz diyarelerin tanısında sıklıkla göz ardı edilen viral ajan- ların önemini bir kez daha ortaya koymaktadır.Objective: Viral agents are the frequent causes of infectious diarrhea in children, but little is known about their epidemiology in Turkey. With this study, we aimed to determine the frequency of gastroenteritis due to rotavirus and adenovirus in the Tekirdag region. Material and Methods: Stool specimens of children with acute gastroenteritis were collected and screened for Group A rotavirus and adenovirus serotype 40-41 antigens, with the immunochromatographic test (RIDA Quick, R-Biopharm, Germany) according to the rec- ommendations of the manufacturer. The results of the subjects were evaluated by examining groups based on the ages: Group A (0 months to 2 years), Group B (3-6 years) and Group C (7-15 years). Results: Of the stool samples, 2135 were tested for the presence of rotavirus and 2117 for adenovirus. 222 (10.4%) samples were positive for rotavirus and 77 (3.6%) were positive for adenovirus antigens. The distribution of rotavirus-positive cases in all the groups analyzed was 63.7%, 27.8%, 8.5% in groups A, B and C, respectively (p&lt;0.001) and the distribu- tion of adenovirus-positive cases in all groups ana- lyzed was 40.3%, 36.3%, 23.4% in groups A, B and C, respectively (p=0.16). No stastistical difference due to gender was obtained for any of the agents (p=0.38, p=0.31 Observation of seasonal variations of the agents showed a higher frequency of rotavirus in December (n=44, 19.8%) and adenovirus in July (n=21, 27.3%). Conclusion: Our results shows the importance of viraagents which are generally missed by routine diagnos- tic tests in identifying the causes of infectious diarrhea

Anatomical Investigation of the Flexor Retinaculum Covering the Tarsal Tunnel in Formaldehyde-Fixed Cadavers

Aim: The flexor retinaculum lies between the medial malleolus of the tibia and the medial process of the calcaneus. It converts grooves on the tibia and calcaneus into the tarsal tunnel. The aim of this study was to analyze the morphometry, the course, and the shape of the flexor retinaculum covering the tarsal tunnel in formaldehyde-fixed cadavers. Material and Methods: Six lower extremities of four formaldehyde-fixed cadavers (four right sides, and 2 left sides) were examined to evaluate the morphometry of the flexor retinaculum. The cadavers were two females and two males with an age range of 60-89 years. A digital caliper (150 mm) and a light microscope were used for measuring parameters. The central length, proximal, midpoint, and distal width, thickness, course, and shape of the flexor retinaculum were examined in this study. Results: The mean central length of the flexor retinaculum was found 42.26±5.18 mm. The mean proximal, midpoint, and distal width of the flexor retinaculum were 29.29±7.29 mm, 29.92±3.66 mm, and 29.76±8.13 mm, respectively. The mean of the thickness was measured at 234.94 µm. The flexor retinaculum coursed vertically in four extremities and coursed obliquely in two extremities. The shape of the retinaculum was triangular in five extremities and quadrangular in only one extremity. Conclusion: The morphometric data obtained from this study can help surgeons during the operations of the tarsal tunnel syndrome. To our knowledge, the width and course of the flexor retinaculum were examined for the first time in this study