Subsurface and through-wall SAR imaging techniques for ground penetrating radar

This paper presents some useful signal processing and synthetic aperture radar imaging techniques for ultra-wide band (UWB) ground penetrating radar. Novel UWB antenna structures are experimentally designed in this work. Raw and processed data collected in the course of experimental studies of subsurface sensing and through-wall imaging scenarios are demonstrated in B-scan and C-scan target images.В статье представлены методы обработки сигнала и получения изображений при помощи радиолокационного синтезирования апертуры (РСА) для сверхширокополосного (СШП) георадара. Предложены новые СШП-антенные структуры. Результаты экспериментального исследования методов подповерхностного зондирования объектов, находящихся под землей и за стеной, представлены в виде изображений, полученных В- и С-сканированием.У статті представлено методи обробки сигналу та отримання зображень за допомогою радіолокаційного синтезування апертури (РСА) для надширокосмугового (НШС) георадара. Запропоновано нові НШС-антенні структури. Результати експериментального дослідження методів підповерхневого зондування об'єктів, що знаходяться під землею і за стіною, представлені у вигляді зображень, отриманих В- та С-скануванням

Köşe kaynak konstrüksiyonlarının statik dayanımının incelenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu çalışmada boru-flanş kaynağına düşük çevrimde orantısal ve orantısal olmayan yüklemeler altında çekme-basma, eğilme ve burulma testleri sonlu elamanlar yöntemi ile Hypela 2 kullanıcı alt programı kullanılarak uygulanmış ve kaynak bölgesindeki malzemenin mekanik gerilme ve gerinim davranışları incelenmiştir. Çalışmada ilk olarak numune malzemesi SAE 1070 çelik olan dairesel çentikli Barkey mili sonlu elamanlar yazılımı kullanılarak modellenmiştir. Numuneye orantısal ve orantısal olmayan yüklemeler altında çevrimsel birleşik eksenel çekme-basma ve radyal burulma testleri uygulanmış ve çentik bölgesinde gerinim davranışları Hypela 2 kullanıcı alt programı kullanılarak incelenmiş ve deneysel sonuçlar ile karşılaştırılmıştır. İzotropik ve Chaboche kinematik pekleşme kurallarına göre çözüm elde edebilen Hypela 2 kullanıcı alt programı Ludwig eşitliğine göre çalıştığı için gerekli parametreler elde edilmiş ve program sonlu elemanlar yazılımına okutularak analizler gerçekleştirilmiştir. Chaboche kinematik ve izotropik malzeme modeline göre elde edilen sonuçlar incelendiğinde programın çentik bölgesindeki malzeme davranışını modelleyebildiği ve Bauschinger etkisinin Chaboche kinematik pekleşme modeli ile oluştuğu görülmüştür. Sonuçların deneysel verilerle az bir hata ile yaklaşım içinde olması Hypela 2 kullanıcı alt programının kullanılabilirliğini göstermiştir. Bir sonraki adımda boru ve flanş malzemesi AISI 304 paslanmaz çelik, kaynak bölgesindeki malzemesi SS308L paslanmaz çelik olan boru -flanş kaynağı aynı sonlu elemanlar programında modellenmiştir. Boru-flanş kaynağına ilk olarak çekme-basma, eğilme ve burulma testleri, düşük bir çevrimde tekil yüklemeler halinde daha sonra ise orantısal ve orantısal olmayan yüklemeler altında birleşik testler halinde uygulanmıştır. Yapılan her bir test lineer elastik, elastik-plastik ve plastik analizler olarak sonlu elemanlar yöntemi kullanılarak yapılmıştır. Elastik-plastik analizlerde malzemenin plastik davranışını tanımlamak için kaynak bölgesinde izotropik pekleşme modeli kullanırken, plastik analizlerde ise izotropik pekleşme modeline göre çözümleme yapan Hypela 2 kullanıcı alt programı kullanılmıştır. Sonuçlar incelendiğinde düşük bir çevrimsel yükleme altında kaynak bölgesindeki malzeme davranışı elastik-plastik analizler ve Hypela 2 kullanıcı alt programı ile modellenebilmiştir. Her bir test sonucunda kaynak bölgesinde oluşan maksimum gerilmelerin kesitlerinin değiştiği, elastik analizlerde bu gerilme değerlerinin daha yüksek çıktığı görülmüştür. Hypela 2 kullanıcı alt programı ile yapılan analizlerde kaynak bölgesindeki malzeme davranışının tahmin edilebildiği görülmüştürIn this study, tensile-compression, bending and torsion tests have been applied to the pipe-flange weld with the finite element method using the Hypela 2 user subroutine file and the mechanical stress and strain behavior of the material in the weld zone have been investigated The material of circular notched Barkey shaft have been determined SAE 1070 steel and the specimen has been modeled using the finite element software. Cyclic combined axial tension-compression and radial torsion tests have been applied to the specimen and strain behavior in the notch region has been investigated using the Hypela 2 user subroutine file and compared with the experimental results. Since the Hypela 2 user subroutine file which can obtain the solution according to the isotropic and Chaboche kinematic hardening rules works according to the Ludwig equation, the necessary parameters has been obtained. When the results obtained according to the hardening model have been investigated, it is seen that Hypela 2 user subroutine can model the behavior of the material in the notch region and the Bauschinger effect has been formed by the Chaboche kinematic hardening model. The results are within compatibility the experimental data and this shows the availability of the Hypela 2 user subroutine. In the next step, the pipe-flange and weld material have been determined respectively AISI 304 stainless steel and SS308L stainless steel and pipe-flange weld has been modeled in the same finite element program. Tension-compression, bending and torsion tests have been applied to the pipe-flange weld at a low cycle. These tests have been applied as singular loads and combined loads. Each test have been made as linear elastic, elastic-plastic and plastic analyzes. In the elastic-plastic analyzes, the isotropic hardening model in the weld zone have been used to describe the plastic behavior of the material, while in the plastic analyzes, the Hypela 2 user subroutine, which analyzes the isotropic hardening model, was used. When the results have been investigated, material behavior in the weld zone under a low cyclic loading have been modeled by elastic-plastic analyzes and Hypela 2 user subroutine. The cross sections of the maximum stresses occurring at the weld zone in each test result have been changed and these stress values have been higher in the elastic analyzes. According to the analysis results of the Hypela 2 user subroutine, it was concluded that the behavior of the material in the source zone can be predicted

The impact of stockmarket development on economic growth in Singapore. econometric study based on an autoregressive distribution lag (ARDL) model covering the period from 1990 to 2020.

The main objective of this paper is to discuss and examine the relationship between the development of stock market and economic growth and to show if the economic growth is positively influenced by stock market development in Singapore. Theoretically, some economists postulate a bidirectional relationship between financial development and economic growth, while others consider that growth drives finance, but that financial development is only a minor growth factor. We used an econometric study based on an autoregressive distribution lag (ARDL) model covering the period from 1990 to 2020 which is supported by the Asian financial crisis of 1997, obtained from various sources, in particular World Bank data and International Monetary Fund reports. Economic growth is expressed by GDP per capita, while stock market development is measured by market capitalization of domestic listed companies (% of GDP), shares traded total value (% of GDP) and stocks traded turnover ratio of domestic shares (%). The results show that the capitalization of domestic listed companies and the turnover ratio of domestic stocks have a positive and significant effect on gross domestic product per capita in the short and long run. However, shares traded total value hasa negative impact on gross domestic product per capita in short and long term. The contribution of our results suggests that stock market development promotes short and long-run growth in Singapore. Our findings can be of direct value to developed or emerging countries while they are of indirect value to less developed economies that may be committed to certain policy or regulatory decisions

Comparison of central corneal thickness measurements using optical low-coherence reflectometry, Fourier domain optical coherence tomography, and Scheimpflug camera

Purpose: To compare the results of central corneal thickness (CCT) measurements obtained using optical low-coherence reflectometry (OLCR), Fourier domain optical coherence tomography (FD-OCT), and a Scheimpflug camera (SC), combined with Placido corneal topography. Methods: A total of 25 healthy subjects were enrolled in the present study, and one eye of each subject was included. A detailed ophthalmic examination was performed in all cases following CCT measurements with OLCR, FD-OCT, and SC. The results were compared using an ANOVA test. Bland-Altman analysis was used to demonstrate agreement between methods. Intra-examiner repeatability was assessed by using intraclass correlation coefficients (ICCs). Results: Statistically significant differences were observed between the results of the CCT measurements obtained using the three different devices (p=0.009). Significant correlations were found between OLCR and FD-OCT (r=0.97; p<0.0001), FD-OCT and SC (r=0.91; p<0.0001), and OLCR and SC (r=0.95; p<0.0001). The 95% limits of agreement (LOA) obtained from Bland-Altman plots were from -7.2 μm to 28.7 μm for OLCR versus FD-OCT, from -19.2 μm to 30.4 μm for OLCR versus SC, and from -42.6 to 32.3 μm for FD-OCT versus SC. Intra-examiner repeatability was excellent for each method, with ICCs >0.98. Conclusion: Although the results of CCT measurements obtained from these three devices were highly correlated with one another and the mean differences between instruments were comparable with the reported diurnal CCT fluctuation, the measurements are not directly interchangeable in clinical practice because of the wide LOA values

NeutroAlgebra Theory, volume I

Neutrosophic theory and its applications have been expanding in all directions at an astonishing rate especially after of the introduction the journal entitled “Neutrosophic Sets and Systems”. New theories, techniques, algorithms have been rapidly developed. One of the most striking trends in the neutrosophic theory is the hybridization of neutrosophic set with other potential sets such as rough set, bipolar set, soft set, hesitant fuzzy set, etc. The different hybrid structures such as rough neutrosophic set, single valued neutrosophic rough set, bipolar neutrosophic set, single valued neutrosophic hesitant fuzzy set, etc. are proposed in the literature in a short period of time. Neutrosophic set has been an important tool in the application of various areas such as data mining, decision making, e-learning, engineering, medicine, social science, and some more

Neutrosophic Algebraic Structures and Their Applications

Neutrosophic theory and its applications have been expanding in all directions at an astonishing rate especially after of the introduction the journal entitled “Neutrosophic Sets and Systems”. New theories, techniques, algorithms have been rapidly developed. One of the most striking trends in the neutrosophic theory is the hybridization of neutrosophic set with other potential sets such as rough set, bipolar set, soft set, hesitant fuzzy set, etc. The different hybrid structures such as rough neutrosophic set, single valued neutrosophic rough set, bipolar neutrosophic set, single valued neutrosophic hesitant fuzzy set, etc. are proposed in the literature in a short period of time. Neutrosophic set has been an important tool in the application of various areas such as data mining, decision making, e-learning, engineering, medicine, social science, and some more