Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Conference Object Citation - WoS: 17Citation - Scopus: 23The Arrows Project: Robotic Technologies for Underwater Archaeology(IOP Publishing Ltd., 2018) Allotta, Benedetto; Costanzi, Riccardo; Ridolfi, Alessandro; Salvetti, Ovidio; Reggiannini, Marco; Kruusmaa, Maarja; Salumäe, Taavi; Lane, David Mike; Frost, Gordon; Tsiogkas, Nikolaos; Cocco, Michele; Gualdesi, Lavinio; Lacava, Giovanni; Roig, Daniel; Gündoğdu, Hilal Tolasa; Dede, Mehmet İsmet Can; Baines, Steven; Tusa, Sebastiano; Latti, Priit; Scaradozzi, DavidThe paper summarizes the main results achieved during the three-year European FP7 ARROWS project (ARchaeological RObot systems for the Worlds Seas). ARROWS concluded at the end of August 2015 and proposed to adapt and develop low-cost Autonomous Underwater Vehicle (AUV) technologies to reduce the operational cost of typical underwater archaeological campaigns. The methodology used by ARROWS researchers identified archaeologists requirements for all the phases of a campaign. These were based on guidelines issued by the project Archaeology Advisory Group (AAG), which comprised of many European archaeologists belonging to the consortium. One of the main goals of the ARROWS project was the development of a heterogeneous team of cooperating AUVs; these comprised of prototypes developed in the project and commercially available vehicles. Three different AUVs have been built and tested at sea: MARTA, characterized by flexible hardware modularity for easy adaption of payload and propulsion systems, U-CAT, a turtle inspired bio-mimetic robot devoted to shipwreck penetration and A-Size AUV, a small light weight vehicle which is easily deployable by a single person. The project also included the development of a cleaning tool for well-known artefacts and maintenance operations. Results from the official final demonstrations of the project, held in Sicily and in Estonia during Summer 2015, are presented in the paper as an experimental proof of the validity of the developed robotic tools.Conference Object Citation - WoS: 1Citation - Scopus: 2Analysis and Application of Advanced Control Strategies To a Heating Element Nonlinear Model(IOP Publishing Ltd., 2017) Turhan, Cihan; Simani, Silvio; Zajic, Ivan; Gökçen Akkurt, GüldenThis paper presents the design of different control strategies applied to a heating element nonlinear model. The description of this heating element was obtained exploiting a data-driven and physically meaningful nonlinear continuous-time model, which represents a test-bed used in passive air conditioning for sustainable housing applications. This model has low complexity while achieving high simulation performance. The physical meaningfulness of the model provides an enhanced insight into the performance and functionality of the system. In return, this information can be used during the system simulation and improved model- based and data-driven control designs for tight temperature regulation. The main purpose of this study is thus to give several examples of viable and practical designs of control schemes with application to this heating element model. Moreover, extensive simulations and Monte- Carlo analysis are the tools for assessing experimentally the main features of the proposed control schemes, in the presence of modelling and measurement errors. These developed control methods are also compared in order to evaluate advantages and drawbacks of the considered solutions. Finally, the exploited simulation tools can serve to highlight the potential application of the proposed control strategies to real air conditioning systems.Article Citation - WoS: 6Citation - Scopus: 11Electrical and Mechanical Properties of Superconducting Mgb2/Mg Metal Matrix Composites(IOP Publishing Ltd., 2006) Eğilmez, Mehmet; Özyüzer, Lütfi; Tanoğlu, Metin; Okur, Salih; Kamer, Orhan; Öner, YıldırhanMgB2/Mg composites were prepared using a metal matrix composite fabrication method that offers the potential to produce superconducting wires as an alternative approach to the powder in tube process. To obtain composites, MgB2 and Mg powders were mixed at different weight fractions and uniaxially pressed in a cylindrical die under the pressure of 0.5 and 1.0GPa for two hours at various temperatures. The x-ray diffraction technique was used for phase identification. Temperature dependence of resistivity and magnetization measurements were carried out to determine superconducting properties. The effects of composite fabrication temperature and the addition of the Mg on the mechanical properties of MgB2/Mg composites were investigated. For this purpose, the compressive mechanical testing was performed to measure the elastic modulus and fracture strength values of the composites. It was found that the relative weight fraction of the Mg and the fabrication conditions of the composites have considerable effect on the superconducting and mechanical properties of the composites.Article Citation - WoS: 10Citation - Scopus: 9Features of Electron and Phonon Processes in Gasb-Fega1.3 Eutectics(IOP Publishing Ltd., 2003) Aliyev, M. I.; Khalilova, A. A.; Arasly, D. H.; Rahimov, R. N.; Tanoğlu, Metin; Özyüzer, LütfiEutectic alloys of GaSb-FeGa1.3 were prepared by the vertical Bridgman method. A microstructure with the needle-shaped metallic FeGa1.3 phase oriented in a specific direction and uniformly distributed within the GaSb matrix was obtained. In GaSb-FeGa1.3 eutectics, the electrical and thermal conductivity, thermal diffusivity, thermoelectric power and Hall coefficients were investigated in a wide temperature range. These properties were measured at different mutual directions of current, thermal flow, magnetic field and metal phase inclusions. The influence of metallic inclusions on these properties was revealed and the distinctive characteristics of electron and phonon processes were established.Article Citation - WoS: 88Citation - Scopus: 92Material Parameters of Quaternary Iii–v Semiconductors for Multilayer Mirrors at 1:55 Μm Wavelength(IOP Publishing Ltd., 1996) Güden, Mustafa; Piprek, JoachimNine quaternary (Al,Ga,In) - (P,As,Sb) semiconductor compounds lattice matched to InP are investigated theoretically. Direct bandgap, refractive index at wavelength, and thermal conductivity are calculated as a function of the composition. These material properties are important, e.g. in distributed Bragg reflectors of vertical-cavity lasers. The alloy systems AlGaAsSb, AlGaPSb and GaInPSb are found to promise better performance of those mirrors than the common InGaAsP system.