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An Energy-Focused Alternative and Complementary Route To the Silk Road
No full textA route, via ships and underwater electric connectors established across the Caspian Sea, could enable goods from Central Asia to be transported to Turkey and through Turkey to other markets. Natural gas-rich countries could transport gas to European markets via this route by converting their natural gas into LNG. In cases where building LNG installations would be uneconomical, they can export energy directly, by conveying gas-generated electricity via underwater electric connectors across the Caspian Sea or by electricity-generating power ships. With the transformation of this route into a new trade corridor due to energy transportation, other products could also be transported to Europe more easily and this would positively impact their economic development, attract investors and promote regional cooperation. This dynamism may create a new commercial corridor for the global supply chain in the context of the Silk Road concept but separate from China’s Belt and Road Initiative (BRI)
Experımental Analysıs Of Shell And Tube Heat Exchanger
No full textIn this study, a shell and tube heat exchanger with 7 inner parallel tubes and 5 baffles are experimentally investigated using deionized water to determine tube sheet thermo-hydraulic characteristic. While shell side flow rate is held constant, tube sheet theoretical Reynolds numbers was aimed to range between 1000 and 5000 to target transition regime. Modified Wilson Plot technique is utilized to determine Nusselt numbers. Thermal results coincide with correlations within acceptable range, hydraulic results highly overestimated flow in pipe correlations. The reason behind hydraulic discrepancy is thought to be due to inlet, outlet, and maldistribution effects. Numerical studies are being conducted to understand underlying phenomenon. In the future, experiments with nanofluids will be conducted and benchmarked with current study results to evaluate the effects of nanofluid
Newborn Hearing Screening Results of Infants Born To Mothers Who Had Covid-19 Disease During Pregnancy: a Retrospective Cohort Study
No full textObjective: Viral infections are known to be a risk factor for neonatal hearing loss. COVID-19 infection has been reported to affect hearing test results in one small sample sized study. We aimed to investigate the incidence the risk of neonatal hearing loss in infants of mothers who had COVID-19 infection during pregnancy, regarding their trimesters, by evaluating the neonatal hearing screening results. Design: In this retrospective case-control study, neonatal hearing test results of 458 women with a history of COVID-19 infection in pregnancy were compared with 339 women who gave birth before the pandemic. Data of pregnant women who attended the COVID-19 outpatient clinic of the emergency service of a tertiary pandemic hospital and who had confirmed infection with a reverse transcriptase-polymerase chain reaction (RT-PCR) test were determined from the hospital's records and their neonatal hearing screening results were analyzed from the national database. Neonates born before 34 weeks, and with reported risk factors in the database such as congenital anomaly or known TORCH infection during pregnancy were excluded. The screening tests, Automated Auditory Brainstem Response or Transient Evoked Otoacoustic Emission (TEOAE), were used for screening, and patients who failed the first screening were reevaluated at least 2 weeks apart with a second screening. Results: The incidence of failed second screening was 1.3% in the COVID-19 group and 2.9% in controls, and no significant difference was observed between the two groups according to the final screening results on the second test. Among the 458 mothers, 8 were infected in first trimester, 126 in second trimester, 127 in third trimester but did not deliver within 15 days after infection and 197 were positive at birth. Six neonates in the infected group failed the second screening (3 [2.4%] in the second trimester, 1 [0.8%] third trimester, and 2 [1.0%] positive at birth). Conclusions: COVID-19 infection during pregnancy was not found to be a risk factor for hearing loss, according to the newborn hearing screening results
Bütünlesik Sayisal Süperiletken Tek Aki Kuantum Girisim Aygiti ve Sayisal Sinyal İsleme Devrelerinin Gelistirilmesi
No full textNowadays, sensitive magnetometers are used in wide application areas. SQUID, Superconducting Quantum Interference Device, is one of the most sensitive superconducting sensors, which is known for its sensitive magnetic flux-voltage characteristic. SQUIDs, which can be used as sensors or amplifiers, have a wide range of uses. Some of those are earthquake detection, medicated magnetoencephalography and magnetocardiography, solid-state physics, biomagnetism, and archeology. There are two types of SQUIDs, called RF SQUID and DC SQUID. Magnetic field sensitivity of RF/DC SQUIDs made of low-temperature superconductors is in the fT/vHz range. Although RF and DC SQUIDs are simple sensors and have relatively high sensitivity, they require complex readout circuits operating at room temperature. This situation both increases the cost and seriously affects the speed of processing of the data.Within the scope of this thesis; it is aimed to design an integrated system including a Digital SQUID and readout circuits on the same chip, which limits DC SQUIDs in terms of cost and speed, and also eliminates complex readout circuits operating at room temperature. In this way, it is desired to increase the sampling frequency of Digital SQUID and to eliminate the need for complex readout circuits operating at room temperature, thanks to digital signal processing circuits with different features (high speed, high sensitivity) on the same chip.Günümüz teknolojisinde çok sayida uygulamada hassas manyetometrelere ihtiyaç duyulmaktadir. Bu alanda; Süperiletken Kuantum Girisim Aygiti (SQUID) olarak bilinen süperiletken sensörler, hassas manyetik aki - voltaj transfer karakteristigine sahip cihazlardandir. Sensör veya yükseltici olarak kullanilabilen SQUID'lerin çok genis kullanim alanlari vardir. Bunlardan bazilari; deprem algilama, ilaçli manyetoensefalografi ve manyeto kardiyografi, kati hal fizigi, biyomanyetizma ve arkeoloji olarak söylenebilir. SQUID; RF SQUID ve DC SQUID olmak üzere iki ana alt baslikta incelenir. Düsük sicaklik süperiletkenlerinden yapilan RF/DC SQUID'lerde manyetik alan hassasiyeti fT/v(Hz ) mertebelerindedir. Yüksek sicaklik süperiltekenleri ile yapilan SQUID'lerde ise bu hassasiyet 100fT/v(Hz )'in altindadir. RF ve DC SQUID'ler yapi olarak basit bir sensör olmalari ve görece yüksek hassasiyete sahip olmalarina ragmen, oda sicakliginda çalisan karmasik okuma devrelerine ihtiyaç duyar. Bu durum maliyeti arttirirken ayni zamanda verileri anlamlandirma hizini da ciddi oranda etkiler. Bu tez kapsaminda; DC SQUID'leri maliyet ve hiz bakimindan kisitlayan, ayrica oda sicakliginda çalisan karmasik okuma devrelerine olan ihtiyaci ortadan kaldiracak sekilde, bir Sayisal SQUID ve ayni yonga üzerinde okuma devrelerinin de bulundugu bütünlesik sistem tasarlanmasi amaçlanmistir. Bu sayede, Sayisal SQUID'in örnekleme frekansinin artmasi ayrica ayni yonga üzerinde bulunan farkli özelliklere sahip (yüksek hiz, yüksek hassasiyet) sayisal sinyal isleme devreleri ile oda sicakliginda çalisan karmasik okuma devrelerine olan ihtiyacin ortadan kalkmasi hedeflenmistir
Application of a Modular Topology Optimization Framework To an Aerospace Bracket Design
No full textIn aerospace industry, optimizing designs has become inevitable in terms of weight and performance requirements. Topology optimization is the most suitable optimization type for use in the conceptual design phase. Even though academic topology optimization algorithms have a modular structure (open to development), they are often useable for a regular design domain. Alternatively, commercial topology optimization software products, on the other hand, are very useful in terms of their solution speed, accuracy, and ability to handle complex or irregular design domains. However, the user is restricted with the optimization algorithms available in the software, and these software do not usually have a modular structure. In this study, a modular topology optimization framework that combines useful features of the academic codes (e.g., modularity) and the commercial software tools (e.g., capability of easily handling complex design domains) is developed. The developed framework is tested on two popular academic topology optimization problems, followed by aerospace bracket design problem. It is observed that the proposed framework usually provides lower objective function values and converges to the optimum result in fewer iterations than the Altair Optistruct topology optimization software
Development of a Prelimenary Aerothermal Design Tool for Airbreathing Propulsion Systems: Turbojet, Turbofan, Ramjet and Scramjet Engines
No full textAirbreathing propulsion systems are engines that generate thrust for aeronautical vehicles and missiles. There are different types of airbreathing propulsion systems such as turbojet, turbofan, turboprop, turboshaft, ramjet, and scramjet engines. In the present study a computational tool that can be used for the preliminary design of turbojet, turbofan, ramjet, and scramjet engines is developed. Preliminary design process of a propulsion system is an important stage in the way of decreasing computational and test costs. For these reasons there some major commercial softwares such as GasTurb, NPSS and GSP that deal with the preliminary design of the airbreathing propulsion systems used by the engineers. The first step in preliminary design is performance calculations of design and off-design propulsion calculations. The first requirement for performance calculations is performing design point calculations and related parametric studies. Most important design parameters are decided to fulfil the mission design requirements such as thrust, thrust specific fuel consumption (TSFC) and specific thrust. After setting the design point parameters, working behaviour of the engine is also analysed at different offdesign points. In this study, software for design point performance calculations was developed for turbojet, mixed/unmixed turbofan, ramjet, and scramjet engines. Firstly, a numerical performance model was implemented into the code. After this point, design point calculations for each engine were validated based on some well-studied engines in the literature. The developed program reads Rayleigh Flow tables which were integrated into the code for calculated specific heat ratios for ramjet, scramjet combustors and afterburners. In addition, basic efficiency estimation tools for compressor, combustion chamber and turbine were implemented into the software. The comparison of results obtained with present methodology and the GasTurb results show very good agreement. The developed software has also an improvement against GasTurb for the design of supersonic intake components. GasTurb uses some ad hoc military standard correlations to calculate the total pressure recovery factor (TPRF) for supersonic intakes. The present methodology uses oblique shock relations based on the number of inlet ramps and ramp angles addition to the mentioned military correlations used by GasTurb. It should be clear that the results obtained using the oblique shock equations are more realistic compared to the military standard
Biyopsi Değerlendirilmesinde Gleason (3+3) Tanılı Hastaların Prostatlarında Kribriform Alan Şüphesi. Kısıtlı Morfolojik Görünüm Hastaları Takip Grubuna Almak için Yeterli Olmayabilir
No full textAmaç: Histolojik derece, prostat kanseri prognozunun en yararlı öngörücüsüdür. Gleason skorlaması, Dünya Sağlık Örgütü tarafından önerilen prostat karsinomu için tek derecelendirme yöntemidir. Gleason (3+3) 6 şu anda tanımlanan en düşük skordur. Radikal materyallerde tüm prostat bölgelerini görebilir ve temel skorlamaya kolayca karar verebiliriz. Ancak biyopside tümörün sadece bir kısmını görebiliriz ve tümörün tümünün histolojik derecesinden kesin emin olamayız. Tümörün kribriform yapılanma potansiyeli varsa biz bunu mevcut yöntemler ile tespit edemiyoruz. Bu çalışmada amacımız iyi diferansiye prostat kanserlerinde moleküler heterojenite saptayabilmektir. Gereç ve Yöntem: Prostat karsinomu Gleason (3+3) tanılı hastalara ait 26 adet prostat iğne biyopsisi Betakatenin, Siklin D1, Pax2 ve Pax8 immünohistokimyasal belirteçleri ile boyanıp incelenmiştir. Bulgular: Tümör yapılarında Betakatenin ile yoğun boyanma izlenmişken, Siklin D1, Pax2 ve Pax8 ile anlamlı bulgu tespit edilememiştir. Sonuç: Betakatenin, Siklin D1, Pax2 ve Pax8 günlük patoloji pratiğinde sıkça kullandığımız belirteçler olup ayrıca ürogenital sistem kanserogenezinde literatürde çalışmalara konu olmuştur. Ancak iyi diferansiye tümöral asiner yapılarda Betakatenin ile yoğun boyanma izlenmişken, Siklin D1, Pax2 ve Pax8 ile anlamlı bulgu tespit edilememiştir
A Consensual Theoretical Framework Study for the Diagnostic Safety-Focused Critical Thinking Training Program in Emergency Medicine Education: A Three-Phase Study
No full textOBJECTIVE: We aimed to determine opinions of the selected experts on the goals and objectives of diagnostic safety-focused critical thinking postgraduate training program in emergency medicine education. This program will be designed to mitigate cognitive errors caused by cognitive biases and heuristics used during diagnostic processes under time pressure and uncertainty in emergency medicine practice. MATERIAL and METHODS: This study is the consensual framework study within the context of the third step of a ongoing doctorate dissertation study in accordance with Kern’s Curriculum Development Model that is a six-step approach. The study is a combination of both quantitative and qualitative research method. We planned a three phase expert group meeting consisting of a need analysis, a semi-structured interview, and a questionnaire study as part of curriculum development process in emergency medicine. The need analysis that is the first phase was made using three stages including literature review, synthesis of the researcher readings about literature, and an unstructured expert meeting. The unstructured expert meeting was made on a virtual platform with two selected emergency medicine specialists. In this section, emergency medicine residents’ needs about diagnostic errors, cognitive biases and safety measures were discussed. It is then defined and invited 12 designated experts for the semi-structured interview phase including both emergency medicine specialists and medical education specialists having masters or doctoral degree. The interview was conducted on the same virtual platform with the participation of eight of 12 experts. In this phase, participants respectively presented their opinion about the subject through prepared five questions and several impromptu questions. The questionnaire study phase was made on a virtual survey platform with the participation of the same 12 experts invited previous semi-structured interview. The participants answered 43 questions generated by researcher at the end of previous phase. Video records of the virtual sections were obtained from the given virtual platform and analyzed by the researcher. The descriptive statistics connected the survey were generated from the answers of 43 questions. RESULT: Twelve domain experts were included in this study. Eighty-three percent of the participants was emergency medicine specialists who are experienced in their domains. Four of the 12 experts (33.3%) had PhD degree on medical education and informatics. In total 14 items were established for target group’s needs analysis at the first phase: 10 items (71.4%) through literature review and synthesizing by researcher and 4 items (28.6%) from the unstructured expert meeting. Two items (33.3%) for the program’s goals and five items (25%) for the program’s objectives were stated at the semi-structured interview. Before the third phase, four goal items (66.7%) and 15 objective items (75%) through literature review and synthesizing were generated by researcher. Totally, 40 items including 14 need items, six goal items and 20 objective items were obtained. At the survey statistics, the participants agreed with 13 need items, five goal items, and 13 objective items with 100%one need item, one goal item, and seven objective items with 83.3-91.7%. CONCLUSION: This is a first consensual framework study conducted in order to define the needs, goals, and objectives of a diagnostic safety-focused critical thinking training program in emergency medicine post-graduate education as far as is known. This is an awareness-raising study because of its significant emphasis about diagnostic error, cognitive biases and critical thinking skills as a de-biasing tool. The 40 items achieved consensus may be used for implementation stage of the given training program
Insansiz Konvansiyonel Kuyruk Rotorlu Helikopter Otomatik Uçus Kontrolü
No full textIn recent years, simple fixed-wing unmanned aerial vehicle systems have attracted all the attention with their game-changing role on the battlefields. This has led to discussions of taking into service of cheapest, simplest, and lightest helicopter platforms, which are designed in the rotary wings' world for some substantial missions such as reconnaissance, surveillance, and military special courier transport. In this context, this study aims to develop a helicopter flight control system in MATLAB ; SIMULINK environment for a conventional tail-rotored rotary wing unmanned aerial vehicle (RUAV) concept to enable automatic flight, landing and take-off. The model was built to simulate a general-purpose helicopter without stabilizer bar and was preferred as the helicopter mathematical model for simulators for years in historical helicopter development literature. This mathematical model, which is inherently nonlinear, is linearized according to the input and output channels by using the linear analysis tool. Thus, controllers are developed to fit this linear model. At the end of the study, it is aimed that, the hover flight, forward flight, landing and take-off according to trim points can be achieved automatically for different altitudes. In the flight control system, firstly, a controller for stability augmentation is designed by establishing internal stability. Then, it is aimed to keep the helicopter to desired speed, altitude, orientation, and position by establishing an attitude-hold external stability loop. It is observed that the model is inherently flying by sliding to far left-hand side (west). After that, the performance of the controllers is examined according to keep the model into the ideal route by adjusting control command inputs for each trim points. Finally, optimum controller gains are found to improve controller performances. P, PI and PID as classical control methods are used within these loops.Son yıllarda, basit sabit-kanatlı insansız hava aracı sistemleri, savaş meydanlarında oyun değiştirici rolleriyle ön plana çıkmaktadır. Bunun sonucunda ise döner kanatlı dünyasında tasarlanabilecek ucuz, basit ve hafif helikopter platformlarının, keşif, gözetleme ve askeri özel kurye taşıma gibi önemli görevler için kullanımları gündeme gelmiştir. Bu çalışma ile konvansiyonel kuyruk rotorlu döner kanatlı bir insansız hava aracı (RİHA) konsepti için MATLAB ve SIMULINK ortamında helikopter uçuş kontrol sistemi geliştirilerek otomatik uçuş, iniş ve kalkış yaptırılması hedeflemektedir. Helikopter matematik modeli olarak, literatürde denge çubuğu olmayan bir genel maksat helikopterinin simülatörde benzetiminin yapılabilmesi için üretilmiş bir model tercih edilmiştir. Yapı olarak doğrusal olmayan bu matematiksel model, paket programın doğrusal analiz aracı kullanılarak giriş ve çıkış kanallarına göre doğrusallaştırılmıştır. Çalışmanın sonunda, trim noktaları olan askı uçuşu, ileri uçuş, iniş ve kalkışın farklı irtifalar için otomatik olarak başarılabilmesi amaçlanmıştır. Uçuş kontrol sisteminde, öncelikle iç kararlılık döngüsü kurularak eksenel dengeyi sağlayan bir eksen sönümleme kontrolcüsü katmanı (SAS) tasarlanmıştır. Ardından, konum-tutma amaçlı dış kararlılık döngüsü kurularak helikopterin hedeflenen hız, yükseklik ve yönelim durumlarına getirilip konum korunmasının (ATT) gerçekleştirildiği amaçlanmıştır. Kontrolcülerin, içsel olarak sol yana doğru kayan modeli trim noktalarındaki durum ve giriş değerlerine göre ideal rotaya yaklaştırabilme performanslarına bakılmıştır. Bunun sonucunda, performansların iyileştirilmesi için en uygun kontrolcü kazançları saptanmıştır. P, PI ve PID gibi klasik kontrol yöntemleri kullanılmıştır