X-ray detector on 2U cubesat BeEagleSAT of QB50

BeEagleSAT is a 2 Unit cubesat to be launched within the EU FP7 project QB 50. It is been produced by Istanbul Technical University and Turkish Air Force Academy. Sabanci University will provide a CdZnTe based semiconductor X-ray detector and associated readout electronics. The detector will utilize cross strip geometry to test the detection system in space, but it will not carry a mask for imaging. The readout will be established by an application specific integrated circuit controlled by a microcontroller. The system will have its own battery and will be turned on intermittently due to power and telemetry constraints. It will characterize the hard X-ray background in 20-150 keV at low Earth orbit conditions as a function of altitude

RETROSPECTIVE ANALYSIS OF MANDIBULAR FRACTURES CASES IN CENTER OF THE EASTERN ANATOLIA REGION OF TURKEY

Objectives: The aim of this retrospective study is to evaluate the etiology of mandibular fractures, the distribution of the age and gender of mandibular fracture patients, the anatomical regions where these fractures are located, and the treatment modalities used in mandibular fracture cases.Materials and Methods: This study employed data obtained via clinical records and the files of patients diagnosed with a mandibular fracture who were treated from 2011 to 2015 at the Department of Oral and Maxillofacial Surgery, Ataturk University.  The etiology of these patients’ mandibular fractures, the distribution of these patients’ age and gender, the anatomical regions where these patients’ fractures were located, and the treatments applied to these patients were recorded by analyzing the obtained data.  Descriptive statistical analysis was performed using Microsoft Excel software.Results: 137 mandibular fracture sites were seen in 103 patients. Of these patients, 81 (79%) were male and 22 (21%) female, making the male-to-female ratio 3.7:1. The patients’ ages ranged between 4 and 78 years, and the mean age was 31.4. Of the various etiologies of mandibular fractures, traffic accident (42 patients, 41%) was most frequent, followed by violence (28 patients, 27%), fall (24 patients, 23%). Of the various anatomical sites where mandibular fractures occurred, the condylar site (36 patients, 26%) was the most common, followed by the body (24%), symphysis and parasymphysis (23%), angle (18%). 58 patients (56%) were treated with closed reduction 42 patients (41%) were treated with open reduction. Three patients (3%) did not receive any treatment.Conclusions: Traffic accidents are the most common etiologic factor of mandibular fracture cases in center of the Eastern Anatolia Region of Turkey. Males and young individuals are the most affected. The condylar site is the most common anatomical site.  Both closed and open reduction methods are commonly used for the treatment of mandibular fractures

Development and in orbit testing of an x ray detector within a 2U cubesat

A CdZnTe based semiconductor X-ray detector (XRD) and its associated readout electronics is developed by the Space Systems Design Laboratory of Istanbul Technical University and High Energy Astrophysics Detector Laboratory of Sabanci University along with an SME partner. The detector will utilize 30 orthogonal cross strip electrodes (and 3 steering electrodes in between anodes) whose geometry is optimized by an extensive set of simulations and energy resolution measurements. The signals will be read by RENA 3b ASIC controlled by MSP 430 microcontroller. The system will have its own battery and will be turned on intermittently due to power constraints. CdZnTe based X-ray detectors have been utilized in space, but they are either pixellated (NuStar), or they consist of many individual crystal pieces (BAT in Swift satellite). The aim of the XRD is to show that large volume crystals with orthogonal strips are viable alternatives, especially for small satellite systems with medium energy resolution requirement. XRD will also characterize the hard X-ray background in 20-200 keV at low Earth orbit conditions as a function of altitude. Due to power and telemetry constraints, the individual events will be corrected for hole trapping on-board, histogrammed, and only the X-ray spectra will be transmitted to the ground station along with a small set of raw data for diagnostic purposes. The XRD is planned to travel into space, as a secondary science mission, on board BeEaglesat which is a 2U CubeSat developed as one of the possible double (2U) CubeSats for the QB50 project. QB50 is a European Framework 7 (FP7) project carried out by a number of international organizations led by the von Karman Institute of Belgium. Its main scientific objective is to study in situ the temporal and spatial variations of a number of key constituents and parameters in the lower thermosphere with a network of about 50 double and triple CubeSats, separated by few hundred kilometers and carrying a determined set of sensors

X-ray detector XRD on BeEagleSat and the development of the improved x-ray detector iXRD

Many interesting astrophysical objects are intense X-ray emitters. Hard X-ray observatories in various sizes have been operating in space and providing exciting scientific results that we cannot obtain in our laboratories on Earth. Nanosatellites with CdZnTe hard X-ray detectors have been launched into orbit as well, and the future holds great promise with such small satellites contributing significantly to high energy astrophysics. One of those satellites is the BeEagleSat which carried the X-ray detector (XRD)to low Earth orbit. The XRD has a 15⨯15⨯3 mm 3 volume CdZnTe detector, a cross-strip electrode design, a RENA readout chip controlled by an MSP 430 microcontroller. Due to a communication problem with the receiver, no science data could have been downloaded from the XRD. Recently, an improved version of the XRD has been designed (called the iXRD)and currently it is in the production phase. The improvements compared to the XRD are the larger volume crystal with almost three times the collecting area, a collimator to limit the field of view for focused scientific return, and a motherboard-daughterboard design to reduce electronic noise

Küp uydular için yedekli uçuş bilgisayarı ve modem geliştirme

CubeSats created new opportunities for academic world. Before CubeSats, only space agencies were capable of launching an experimental spacecraft. After CubeSats number of small companies and COTS products with heritage increased, therefore prices for space products dropped to a reasonable level. In addition, commercial rockets are developed with various size and payload capacities, this leads to cheaper piggyback launches. Currently even small university laboratories with limited budgets are able to develop and launch CubeSats. Today many CubeSat projects depend on COTS OBC developed almost 10 years ago.In this thesis, a new advanced OBC is developed. Motivation of thesis is rapid developing aerospace industry of Turkey. ITUpSAT1, the fisrt satellite developed in Turkey launched in 2009 with COTS OBC and modem. It is clear that using COTS single board for each system is volume inefficient for 1U CubeSats. A new efficient design will lead advanced CubeSats.Different hardware and software designs are implemented on OBC to ensure proper mission. A relatively new ulta-low power microcontroller is selected, older version of which has flight heritage. Software libraries are implemented for future CubeSat projects. Enhancements on COTS bus is made to increase reliability and compatibility. A simple low power modem is implemented on same board to ensure communication without increasing volume by adding another modem. Batteries are also implemented into OBC so that even failure of rest of spacecraft communication will established and at least failure reasons will be researched for future missions. All three systems are doubled to have a dual redundant system for fault tolerancy and everything is fitted on a single PCB.The system is build and tested. Table-top and range testing are handled successfully. Table-top model tested software libraries. Range tests simulate 700 to 1400 km range between a LEO satellite and standard CubeSat GS. TVAC and radiation tests are planned and documented, but due to low budget of master thesis, this test will be handled during a real CubeSat projects testing phase.As a conclusion a generic reliable OBC is developed. With professional fabrication and testing process could space qualify the new system and then it could be used on future projects without any problem.Küp uydular geliştirilmeye başladığından beri akademik dünya için uzayın kapıları açıldı. Küp uydulardan once deneysel uydular ancak geniş bütçeli uzay ajansları tarafından atılabilmekte idi. Küp uydulardan sonra ise irili ufaklı firmalar belirli standartlara göre geliştirdikleri ürünleri piyasaya sürmeye başladılar. Bu ürünler kullanıldıkça uçuş geçmişine sahip oldular ve fiyatlar rekabet dolayısı ile azaldı. Aynı şekilde farklı ağırlık ve boyuttaki uydular için geliştirilen ticari roketler seçenekleri çoğalttıkları gibi küp uyduları da müşteri olarak kabul etmeye başladılar. Bu sayede fırlatma giderleri de önemli ölçüde azalmış oldu. Günümüzde düşük bütçeli üniversite laboratuvarları dahi rahatlıkla küp uydu geliştirerek fırlatma şansına sahiptirler. Birçok uydu projesi de yaklaşık 10 yıl önce geliştirilen hazır ürünlere dayalı olarak geliştirilmektedir.Tez için farklı yazılım ve donanımlar implement edilmiştir. Piyasadaki ürünlere gore daha yeni olan bir mikrokontrolcü uçuş bilgisayarı için seçildi. Bu mikrocontrolcüde kullanmak ve gelecekteki projelere yardımcı olmak üzere yazılım kütüphaneleri ve sürücüler geliştirildi. Halihazırda kullanılan system yollarına bazı eklemeler yapıldı. Basit ve düşük güç harcayan bir modem tasarlanarak bilgisayar ile aynı kart üzerine eklendi. Bunlara ek olarak uydunun gücünün kesilmesi durumunda dahi çalışması için aynı kart üzerine pil eklendi. Son olarak her sistemin eşi olan yedek bir sistem aynı kart üzerine eklendi. Bu sayede gelecekteki görevlerde bir sorun olması durumunda dahi en azından sorunun ne olacağı incelenebilecektir. Sonuç olarak piyasadaki ve diğer topluluklar tarafından üretilen altsistemlere göre çok daha gelişmiş bir ürün tasarlandı. Tasarlanan ürünün her türlü uzay şartına dayanması için gelişmiş yedeklilik yöntemleri kullanıldı.xxiiiTasarlanan ürünün ilk olarak çift katlı bakır PCB olarak tasarlandı. Bu tasarımda RF sinyallerin geçtiği yollar gerektiği gibi 50 ohm olacak şekilde ayarlandı. Tasarım İTÜ MEAM laboratuarlarında bulunan PCB prototip cihazları kullanılarak üretildi. Kullanılan devre elemanları el ile üretmek için çok küçük olduğundan üretimde çok hassas cihazlar kullanıldı. PCB üzerine lehim yapmak için stencil üretildi. Stencil ile sürülen lehim üzerine devre elemanları çok hassas cihazlar yardımı ile yerleştirildi ve özel fırınlar kullanılarak lehim eritildi ve üretim işlemi tamamlanmış oldu.Üretilen sistemi test etmek için küp uydularda kullanılan standart test metodolojisi kullanıldı. İlk olarak üretilen yazılım ve donanım masaüstünde denendi ve hataları giderildi. Daha sonra uydunun gönderileceği yükseklikte çalışacağından emin olmak için mesafe testleri yapıldı. Mesafe testlerinde ise standart bir alçak yörünge küp uydusunun 700 ila 1400 km arası değişen mesafeleri simüle edildi. Daha sonra sistemin uzay ortamında çalışıp çalışmayacağını sınamak için İTÜ bünyesinde bulunan USTTL tesislerinde termal vakum testi yapıldı. Bu testlerde sistemler çok düşük vakumde çalıştırıldı ve performansları izlendi. Aynı şekilde vakum ortamında uzay sıcaklıklarını denemek için ortam sıcaklığı değiştirildi ve çalışma performansları kaydedildi. Daha sonra tamamlanması için radyasyon testleri de planlandı ve dökümantasyonları tamamlandı. Bu sayede herhangi bir küp uydu projesi dahilinde yapılacak olan testlerin uçuş bilgisayarını uzaya kalifiye etmesi tasarlandı.Sonuç olarak jenerik bir uçuş bilgisayarı tasarlandı, üretildi ve test edildi. İleride yapılacak olan profesyonel üretim ve testler sistemin gelecekteki görevlerde rahatlıkla kullanılmasına olanak sağlayacaktır. Gelecekte geliştirilecek olan küp uydu projelerinde rahatlıkla kullanılabilecek kalitede bir altsistem geliştirildi.M.Sc.Yüksek Lisan

BANK AUDITS AND RISK MANAGEMENT IN TURKEY

Banks are of vital importance in economies, because their bankruptcy leads to losses for millions of small savers. As a result, banks are closely audited all around the world. The prerequisite for a healthy economic system is the use of internal and external auditing and risk management in banks. In this study, the developments of internal and external audits in banking have been summarised according to regulations in Turkey and significant risks have been discussed in terms of bank management decisions and risk management. Additionally, Basel regulations and capital adequacy have been analysed and the problems that affect the banking sector in Turkey have been summarised. The aim of our study is to determine the current situation and this study is based on a literature and regulation review

Crystal Structure and Thermal Decomposition of Square Planar Ni (II) Complexes with ONS Type Ligands (vol 40, pg 788, 2010)

durmus, sefa/0000-0001-6974-513XWOS: 000285973600018

Gartenbauliche merkmale des maronen-anbaus in der Türkei

Chestnut is one of the important nut crops in Turkey. However, studies on production, marketing, and characteristics of chestnut growers is very limited in the literature. Also, the type of chestnuts production changes depending on the region. This is the result of being chestnut is a natural forest tree. To find out the growing characteristics of chestnut in Turkey a highly structured questionnaire study is done. The purposes of this study, therefore, are (i) to explore the typology of chestnut growers; (ii) to outline the characteristics of the farms, their production, care activities (such as weed management, fertilization, orchard floor etc., major insects and disease problems and their management), and harvest characteristics; and, (iii) to analyze marketing characteristics (storage, marketing channel, market structure). The bulk of the research data are collected from randomly selected 279 chestnut growers all around the Turkey. Descriptive statistics were used for summarize the research results. The results of per characteristic were presented with detailed according to the regions. For this aim, recommendations are also provided for improving chestnut production