38 research outputs found
Effective of Preoperative 18 FDG / PET-CT in the Determination of Boost Volume in Adjuvant Radiotherapy After Breast-Conserving Surgery
No full textBehavior of Soil Reinforcements in Slopes
No full textAbstractIn geotechnical and transportation engineering, especially road constructions in cuts and deep excavation problems are solved by using different supporting excavation methods. Soil reinforcements are chosen due to easy and economic application. In this study, behavior of supported slopes with geotextiles and geogrids were analyzed by performing experiments on slope models in the laboratory. In the experiments, a static loading was applied to find failure surface and deformations for each case. Additionally, slopes were designed by using Plaxis program. At the end of the study, experimental and analytic models were compared and also behavior of models were presented
DC/DC Converters for Multiterminal HVDC Systems: Based on Modular Multilevel Converter
No full textThe increase in the energy demand has resulted in searching for new energy sources. Due to the increased prices of fossil fuels and the environmental issues, renewable energy sources has become popular in Europe. Renewable energy generation such as wind, solar and wave has point-to-point connections with the main grid. In order to minimize the disadvantages of renewable energy sources like energy fluctuations, multi-terminal systems are favoured interconnecting energy generation stations among them with the main grid. The long distance interconnection especially for offshore wind farms and intercontinental connections is not possible with traditional alternating current (AC) technology because of the limited power transfer. Therefore, high voltage direct current (HVDC) technology is considered as the main element for the future multi-terminal grid. The conversion between AC and DC is preferred via voltage source converters (VSC) as they offer more flexible power control compared to traditional current source converters in other words line commutated converters (LCC). HVDC power transmission schemes have been constructed depending on the technology of the time, which means that there is no standardization in voltage levels and configurations of the HVDC schemes. Therefore, the connection of such systems operating at different voltage levels and/or in different schemes such as monopole and bipolar systems for the future multi-terminal DC grids requires DC/DC converters. Although the voltage level and the configurations are the same for both DC systems, DC/DC converter may be required for the power flow control in multi-terminal DC grid. The modular multilevel converter (MMC) seems as the most suitable converter in this application due to its advantages such as low switching losses, high scalability and modularity. MMC control structures are introduced and front-to-front connection of two MMC forming a DC/AC/DC converter is modelled and simulated for different applications such as interconnecting systems with same voltage levels, different voltage levels or different configurations in this study. The passive element sizes of MMC submodules are also compared for different AC side frequency as the component sizes can be decreased thanks to the increase in the AC frequency which has a disadvantage of higher switching losses. Moreover, the designed converters are tested in multi-terminal DC grids to check their performance and functionality.Electrical Engineering, Mathematics and Computer ScienceElectrical Sustainable EnergyErasmus Mundus, European Wind Energy Master (EWEM), Electric Power System Trac
Underemployment : a skills utilisation perspective
No full textMore than half of all employees believe that the skills they possess are higher than those required to do their present jobs. This is one of several findings reported in a research paper on "under-employment" in the current edition of the University of Strathclyde's Fraser of Allander Review published today. According to the author of the paper, John Sutherland of the Scottish Centre for Employment Research at the university, this provides further evidence that "under-employment" is as important a policy problem as "unemployment"
CO2 emission during the combustion of Orhaneli lignite coal
No full textPurpose - In Turkey, dependence on foreign countries for energy is a problem which upsets all economic balances. Turkey's biggest fossil energy source is lignite coal. Therefore, energy conversion of lignite in thermal plants, causing minimum environmental effect is extremely important. The basic problem in terms of the combustion technology is to improve the combustion technology that can burn the low-qualified fuels that do not have standard fuel features (lignite, peat, schist). The most suitable technology today for the efficient and clean combustion of nonstandard low-qualified fuels is the combustion at fluidized-bed technology. In this study, CO2 emission that occurs during the combustion of Orhaneli coal that is one of our native low-qualified lignite, has been investigated according to the experimental study. Design/methodology/approach - For this combustion experiment, laboratory-scaled circulating fluidized-bed (CFB) process that exists at TU BITAK-MAM Energy Institute which has been designed and used before has been used. The effect of excess-air coefficient, combustion type and bed temperature to the greenhouse gas formation and CO2 emission has been investigated experimentally. In terms of flue gas emissions, it has been detected that the decrease of the amount of CO2 that has occurred has no positive effects on combustion efficiency, water vapor, SO2, NOx, CO and other gases which occur during deficient combustion must be thought as a whole and each reaction affects each other similar to complex reactions. Findings - As a consequence of measuring CO2 emissions over 10 minute periods, CO2 emissions are 12.43 percent average, CO2 decreases at different air coefficient values; Often form undesirable side reactions such as CO, NOx with back and forth reactions. Originality/value - The importance of aerodynamic structure of the system, and the losses and leakages forming in the system has been observed experimental and affected parameters are evaluated
A Turkish Hate Speech Dataset and Detection System
No full textSocial media posts containing hate speech are reproduced and redistributed at an accelerated pace, reaching greater audiences at a higher speed. We present a machine learning system for automatic detection of hate speech in Turkish, along with a hate speech dataset consisting of tweets collected in two separate domains. We first adopted a definition for hate speech that is in line with our goals and amenable to easy annotation; then designed the annotation schema for annotating the collected tweets. The Istanbul Convention dataset consists of tweets posted following the withdrawal of Turkey from the Istanbul Convention. The Refugees dataset was created by collecting tweets about immigrants by filtering based on commonly used keywords related to immigrants. Finally, we have developed a hate speech detection system using the transformer architecture (BERTurk), to be used as a baseline for the collected dataset. The binary classification accuracy is 77% when the system is evaluated using 5-fold cross validation on the Istanbul Convention dataset and 71% for the Refugee dataset. We also tested a regression model with 0.66 and 0.83 RMSE on a scale of [0-4], for the Istanbul Convention and Refugees datasets
Similiar Efficacy of Tofacinitib on Disease Activity in Rheumatoid Arthritis Patients with and without Previous Biologicals; Results from the Turkbio Registry
No full textIntrinsic Spin Hall Edges
No full textThe prediction of intrinsic spin Hall currents by Murakami et al. and Sinova et al. raised many questions about methods of detection and the effect of disorder. We focus on a contact between a Rashba-type spin-orbit coupled region with a normal two-dimensional electron gas and show that the spin Hall currents, though vanishing in the bulk of the sample, can be recovered from the edges. We also show that the current-induced spin accumulation in the spin-orbit coupled system diffuses into the normal region and contributes to the spin current in the leads
The Effect of Smoking on Response to Tumor Necrosis Factor-Alpha Inhibitor Treatment in Ankylosing Spondylitis Patients: Results from the TURKBIO Registry
No full textThe Effect of Smoking on Response to Tumour Necrosis Factor-Alpha Inhibitor Treatment in Psoriatic Arthritis Patients: Results from the TURKBIO Registry
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