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Petrov, N. (author)Modern surveillance radars are designed to detect moving targets of interest in an adverse environment, which can encompass strong unwanted reflections from ground or sea surface, clouds, precipitation, etc. Detection of weak and small moving targets in environmental clutter remains, however, a challenging task for the existing radar systems....doctoral thesis 2019
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Kumar, A. (author), Agarwal, G. (author), Petrov, R.H. (author), Goto, S. (author), Sietsma, J. (author), Herbig, M. (author)The formation of White (WEL) and Brown Etching Layers (BEL) on rail raceways during service causes the initiation of microcracks which finally leads to failure. Detailed characterization of the WEL and the BEL in a pearlitic rail steel is carried out from micrometer to atomic scale to understand their microstructural evolution. A...journal article 2019
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Butt, Muhammad Abdullah (author), Lesina, Antonino Calà (author), Neugebauer, Martin (author), Bauer, T.A. (author), Ramunno, Lora (author), Vaccari, Alessandro (author), Berini, Pierre (author), Petrov, Yuriy (author), Danilov, Denis (author)Carbon-based and carbon–metal hybrid materials hold great potential for applications in optics and electronics. Here, a novel material made of carbon and gold–silver nanoparticles is discussed, fabricated using a laser-induced self-assembly process. This self-assembled metamaterial manifests itself in the form of cuboids with lateral...journal article 2019
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Goulas, C. (author), Kumar, A. (author), Mecozzi, M.G. (author), Castro-Cerda, Felipe Manuel (author), Herbig, Michael (author), Petrov, R.H. (author), Sietsma, J. (author)Atomic-scale investigation was performed on 51CrV4 steel, isothermally held at different temperatures within the bainitic temperature range. Transmission electron microscopy (TEM) analysis revealed three different morphologies: lower, upper, and inverse bainite. Atom Probe Tomography (APT) analysis of lower bainite revealed cementite...journal article 2019
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le Chevalier, F. (author), Petrov, N. (author)When designing a new radar system, standard resolution trade-offs play a major role, providing the basic parameters of the radar, such as size, update rate, and range. Besides, diversity has long been used for mitigating fading effects due to the fluctuation of targets and clutter. However, with the arrival of more flexible systems, using...journal article 2019
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Papaefthymiou, Spyros (author), Banis, Alexandros (author), Bouzouni, Marianthi (author), Petrov, R.H. (author)The current work focuses on complex multiphase microstructures gained in CrMo medium carbon steel after ultra-fast heat treatment, consisting of heating with heating rate of 300 C/s, 2 s soaking at peak temperature and subsequent quenching. In order to better understand the microstructure evolution and the phenomena that take place during...journal article 2019
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le Chevalier, F. (author), Petrov, N. (author)Wideband radars have been proposed for detection of moving targets, with unique capability of non-ambiguous detection due to range migration. Moreover, frequency diversity has long been used for mitigating the fading effects caused by target and clutter fluctuations. The real benefits of wideband radars are difficult to analyze, since they...journal article 2019
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Valdes-Tabernero, M. A. (author), Celada-Casero, Carola (author), Sabirov, I. (author), Kumar, A. (author), Petrov, R.H. (author)This work focuses on the effect of soaking time on the microstructure during ultrafast heat treatment of a 50% cold rolled low carbon steel with initial ferritic-pearlitic microstructure. Dilatometry analysis was used to estimate the effect of heating rate on the phase transformation temperatures and to select an appropriate inter-critical...journal article 2019
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Kumar, A. (author), Saxena, A. K. (author), Kirchlechner, C. (author), Herbig, M. (author), Brinkmann, S. (author), Petrov, R.H. (author), Sietsma, J. (author)Failure in engineering materials like steels is strongly affected by in-service deleterious alterations in their microstructure. White Etching Layers (WELs) are an example of such in-service alterations in the pearlitic microstructure at the rail surface. Cracks initiate in the rails due to delamination and fracture of these layers and...journal article 2019
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Banis, Alexandros (author), Hernandez Duran, E.I. (author), Bliznuk, Vitaliy (author), Sabirov, Ilchat (author), Petrov, R.H. (author), Papaefthymiou, Spyros (author)The effect of ultra-fast heating on the microstructures of steel has been thoroughly studied over the last year as it imposes a suitable alternative for the production of ultra high strength steel grades. Rapid reheating followed by quenching leads to fine-grained mixed microstructures. This way the desirable strength/ductility ratio can be...journal article 2019
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Petrov, N. (author), le Chevalier, F. (author), Yarovoy, Alexander (author)Adaptive detection of fast moving targets by means of high range resolution radar is considered. It is assumed that a fast-moving target of interest has a few range cells migration during the coherent processing interval and the clutter power fluctuates rapidly along the range. Therefore, the target competes with the clutter responses in a few...conference paper 2019
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Hajizad, O. (author), Kumar, A. (author), Li, Z. (author), Petrov, R.H. (author), Sietsma, J. (author), Dollevoet, R.P.B.J. (author)Wheel–rail contact creates high stresses in both rails and wheels, which can lead to different damage, such as plastic deformation, wear and rolling contact fatigue (RCF). It is important to use high-quality steels that are resistant to these damages. Mechanical properties and failure of steels are determined by various microstructural...journal article 2019
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Danielsen, H. K. (author), Gutiérrez Guzmán, F. (author), Muskulus, Michael (author), Rasmussen, B. H. (author), Shirani, M. (author), Cornel, D. (author), Sauvage, P. (author), Wu, J. (author), Petrov, R.H. (author), Jacobs, G. (author)WEC is an aggressive and unpredictable failure mode affecting bearings in particular in the wind energy sector. This paper focuses on the most common used method for WEC laboratory accelerated testing, the FE8 type test rigs using martensitic through hardened 100Cr6 cylindrical roller thrust bearings, analyzing the load conditions, test...journal article 2019
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Dimitrova, Rositza (author), Petrov, R.H. (author), Kuzmanov, Pavel (author), Velikov, Аngel (author), Manolov, Valentin (author)Two types of A356 alloy castings in initial and modified with nanoparticles condition produced by gravitational casting were studied. Samples, as-cut from the castings, were subjected to light optical microscopy (LM), thermal analyses, Electron Backscattered Diffraction (EBSD) and Scanning Transmission Electron Microscopy (STEM) analyses....journal article 2019
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Naeimi, M. (author), Li, S. (author), Li, Z. (author), Wu, J. (author), Petrov, R.H. (author), Sietsma, J. (author), Dollevoet, R.P.B.J. (author)This research presents a coupled thermomechanical modelling procedure for the wheel-rail contact problem and computes the flash-temperature and stress-strain responses when thermal effects are present. A three-dimensional elasto-plastic finite element model was built considering the wheel-track interaction. When the wheel is running on rail,...journal article 2018
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Petrov, N. (author), le Chevalier, F. (author), Yarovoy, Alexander (author)This paper deals with the problem of coherent radar detection of fast moving targets in a high range resolution mode. In particular, we are focusing on the spiky clutter modeled as a compound Gaussian process with rapidly varying power along range. Additionally, a fast moving target of interest has a few range cells migration within the coherent...journal article 2018
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Hofer, Christina (author), Bliznuk, Vitaliy (author), Verdiere, An (author), Petrov, R.H. (author), Winkelhofer, Florian (author), Clemens, Helmut (author), Primig, Sophie (author)The multiphase microstructure of carbide-free bainitic steels comprises bainitic ferrite laths, retained austenite with different morphologies, a minor fraction of carbides and so-called martensite-austenite areas, which partially transform during the last cooling step. While the other constituent received much attention, little is known...journal article 2018
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Alizadeh Otorabad, H. (author), Tehrani, Parisa Hosseini (author), Younesian, Davood (author), Sietsma, J. (author), Petrov, R.H. (author)Studying the temperature evolution of the thermally affected zone (TAZ) of sliding surfaces is crucial because of its influence on microstructural evolution, wear, and fatigue. Due to the complexity of thermal analysis of sliding bodies, relationships that predict their surface temperature evolution are very helpful because they can be used as...journal article 2018
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Wu, J. (author), Petrov, R.H. (author), Kölling, S. (author), Godet, Stephane (author), Sietsma, J. (author)Micro- to nano-scale characterization of the microstructures in the white etching layer (WEL), observed in a Dutch R260 Mn grade rail steel, was performed via various techniques. Retained austenite in the WEL was identified via electron backscatter diffraction (EBSD), automatic crystallographic orientation mapping in transmission electron...journal article 2018
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Eftekharimilani, P. (author), van der Aa, E.M. (author), Petrov, R.H. (author), Hermans, M.J.M. (author), Richardson, I.M. (author)The effect of an automotive paint bake (PB) thermal cycle on the microstructural evolution and the mechanical properties of resistance spot welded advanced high strength steel is presented in this work. Mechanical behavior of the heat-treated welds reveals an increase in maximum cross-tension strength, displacement and subsequently energy...journal article 2018