Τμήμα Μηχανικών Μηχανολογίας και Κατασκευαστικής / Department of Mechanical and Manufacturing Engineering: Recent submissions

Now showing items 761-780 of 1036

    • Article  

      Spark ignitable ball milled powders of Al and Ni at NiAl composition 

      Hadjiafxenti, A.; Gunduz, I. E.; Doumanidis, C. C.; Rebholz, Claus (2014)
      Low-energy ball milling of aluminum and nickel particles with an overall composition corresponding to the NiAl intermetallic phase was performed up to milling durations of 13 h. The milled powders and cold-compacted pellets ...
    • Article  

      Synthesis of reactive Al/Ni structures by ball milling 

      Hadjiafxenti, Anastasia; Gunduz, Ibrahim Emre; Tsotsos, Chrysostomos; Kyratsi, Theodora; Doumanidis, C. C.; Rebholz, Claus (2010)
      Material systems that exhibit self-propagating exothermic reactions (SPER) can be potentially used for nano/microscale heater purposes in thermal nanomanufacturing applications. We propose that ball milling (BM) is a simple ...
    • Article  

      The influence of structure on thermal behavior of reactive Al–Ni powder mixtures formed by ball milling 

      Hadjiafxenti, A.; Gunduz, I. E.; Tsotsos, C.; Kyratsi, Theodora; Aouadi, S. M.; Doumanidis, C. C.; Rebholz, Claus (2010)
      Ball milling (BM) was used to produce reactive Al–Ni powder mixtures that exhibit self-propagating exothermic reactions (SPER) for nano–micro heater applications. Powders with an Al–Ni molar ratio of 1:3 were milled, cold ...
    • Article  

      Alternating amphiphilic multiblock copolymers: Controlled synthesis via RAFT polymerization and aqueous solution characterization 

      Hadjiantoniou, N. A.; Krasia-Christoforou, T.; Loizou, E.; Porcar, L.; Patrickios, C. S. (2010)
      Four linear amphiphilic multiblock copolymers based on 2-(dimethylamino) ethyl methacrylate (DMAEMA, hydrophilic) and methyl methacrylate (MMA, hydrophobic), bearing from two to five blocks, were synthesized using reversible ...
    • Article  

      Effect of sintering in ball-milled K 2Bi 8Se 13 thermoelectric nano-composites 

      Hatzikraniotis, E.; Ioannou, M.; Chrissafis, K.; Chung, D. Y.; Paraskevopoulos, K. M.; Kyratsi, Theodora (2012)
      K 2Bi 8Se 13 has many attractive features for thermoelectric applications. Recently, K 2Bi 8Se 13-based nanocomposite materials, consisting of nano-crystalline, micro-crystalline and amorphous phases, have been fabricated ...
    • Conference Object  

      FTIR Reflectivity spectra of Thermoelectric K2Sb 8Se13 crystals 

      Hatzikraniotis, E.; Hassapis, Th; Kyratsi, Theodora; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceAffiliation: Department of Mechanical and Manufacturing Engineering, University of CyprusAffiliation: Department of Chemistry, Michigan State University, MI 48824, United StatesCorrespondence Address: Hatzikraniotis, E.Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece, 2006)
      Investigations of ternary and quaternary compounds, Bi and Sb chalcogenides, have shown that several multinary compounds containing alkali metals present promising thermoelectric properties. In this work, the FTIR reflectivity ...
    • Conference Object  

      IR reflectivity studies of mechanically alloyed PbTe nanocrystals 

      Hasapis, T. Ch; Papageorgiou, C.; Hatzikraniotis, E.; Kyratsi, Theodora; Paraskevopoulos, K. M. (Affiliation: Department of Physics, Aristotle University of Thessaloniki, 54123 Thessaloniki, GreeceAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusCorrespondence Address: Hasapis, T. Ch.Department of Physics, Aristotle University of Thessaloniki, 54123 Thessaloniki, Greece, 2009)
      Nano-crystalline lead telluride powder was synthesized by mechanical alloying using a high-energy planetary ball mill. The broadening of the X-ray diffraction peaks vs ball milling time, indicates small crystalline size ...
    • Article  

      Investigations on the self propagating reactions of nickel and aluminum multilayered foils 

      Gunduz, Ibrahim Emre; Fadenberger, K.; Kokonou, Maria; Rebholz, Claus; Doumanidis, C. C. (2008)
      The self-propagating reaction of nickel-aluminum thin film multilayers with a bilayer thickness of 43 nm was investigated using high-speed optical camera and infrared thermometry. The results indicate a two-stage reaction ...
    • Article  

      MHD flow past a circular cylinder using the immersed boundary method 

      Grigoriadis, D. G. E.; Sarris, I. E.; Kassinos, Stavros C. (2010)
      The immersed boundary method (IB hereafter) is an efficient numerical methodology for treating purely hydrodynamic flows in geometrically complicated flow-domains. Recently Grigoriadis et als. [1] proposed an extension of ...
    • Article  

      Immersed boundary method for the MHD flows of liquid metals 

      Grigoriadis, D. G. E.; Kassinos, Stavros C.; Votyakov, E. V. (2009)
      Wall-bounded magnetohydrodynamic (MHD hereafter) flows are of great theoretical and practical interest. Even for laminar cases, MHD simulations are associated with very high computational cost due to the resolution ...
    • Article  

      Modeling of the self-propagating reactions of nickel and aluminum multilayered foils 

      Gunduz, I. E.; Fadenberger, K.; Kokonou, M.; Rebholz, Claus; Doumanidis, C. C.; Ando, T. (2009)
      In this study, we performed simulations of self-propagating reactions of nanoscale nickel-aluminum multilayers using numerical methods. The model employs two-dimensional heat transfer equations coupled with heat generation ...
    • Article  

      Diagnostic properties of structure tensors in turbulent flows 

      Grigoriadis, D. G. E.; Langer, C. A.; Kassinos, Stavros C. (2010)
      The behavior of turbulence structure tensors based on Large-Eddy Simulations (LES) in a wide range of turbulent channel flows is presented. The structure tensors provide significant physical information on the character ...
    • Article  

      Fabrication, characterization and applications of novel nanoheater structures 

      Gu, Z.; Cui, Q.; Chen, J.; Buckley, J.; Ando, T.; Erdeniz, D.; Wong, P.; Hadjiafxenti, A.; Epaminonda, P.; Gunduz, I. E.; Rebholz, Claus; Doumanidis, C. C. (2013)
      Nanoheaters are reactive nanostructures that can generate localized heat through controlled ignition. Besides the widely used nanofoil structure with multiple alternative Al-Ni layers, various new nanostructures have been ...
    • Article  

      Spark ignitable Ni-Al ball-milled powders for bonding applications 

      Gunduz, I. E.; Kyriakou, A.; Vlachos, N.; Kyratsi, Theodora; Doumanidis, C. C.; Son, S.; Rebholz, Claus (2014)
      Ball milling of aluminum (Al) and nickel (Ni) particles at the NiAl composition can produce reactive powders with low spark ignition thresholds similar to magnetron sputtered multilayer foils (MFs). Such powders can replace ...
    • Article  

      Simulations of nanoscale Ni/Al multilayer foils with intermediate Ni2Al3 growth 

      Gunduz, I. E.; Onel, S.; Doumanidis, C. C.; Rebholz, Claus; Son, S. F. (2015)
      Nanoscale multilayers of binary metallic systems, such as nickel/aluminum, exhibit self-propagating exothermic reactions due to the high formation enthalpy of the intermetallic compounds. Most of the previous modeling ...
    • Article  

      Imaging the destruction of individual ultrasound contrast microbubbles with diagnostic ultrasound 

      Guan, Jingfeng; Matula, Thomas J.; AVERKIOU, MICHALAKIS A. (2018)
      Ultrasound imaging of ultrasound contrast agent fragmentation in a water bath was performed with the color Doppler mode of the HDI 5000 (Phillips Ultrasound). A highly diluted suspension of ultrasound contrast microbubbles ...
    • Article  

      LES of the flow past a rectangular cylinder using the immersed boundary concept 

      Grigoriadis, D. G. E.; Bartzis, J. G.; Goulas, A. (2003)
      Incompressible turbulent flow past a long square cylinder is investigated using large eddy simulations LES). Results are presented and compared with available experimental databases for a Reynolds number Red = 22 000. The ...
    • Article  

      Efficient treatment of complex geometries for large eddy simulations of turbulent flows 

      Grigoriadis, D. G. E.; Bartzis, J. G.; Goulas, A. (2004)
      Incompressible turbulent flow over a backward facing step at Reh=5100 is investigated by large eddy simulations (LES). The ratio of the oncoming boundary layer thickness δ to the step height h was set to 1.2. Additionally ...
    • Article  

      Coherent structures in oscillating turbulent boundary layers over a fixed rippled bed 

      Grigoriadis, D. G. E.; Balaras, E.; Dimas, A. A. (2013)
      Coherent structures generated by oscillating turbulent boundary layers with or without a unidirectional current over a fixed, rippled bed are presented. The effect of ripple height and current intensity on the characteristics ...
    • Article  

      Large-eddy simulation of wave turbulent boundary layer over rippled bed 

      Grigoriadis, D. G. E.; Dimas, A. A.; Balaras, E. (2012)
      Large-eddy simulation (LES) of turbulent boundary layer induced by external oscillatory flow without or with a unidirectional component over rippled bottom is presented. These flows represent prototype turbulent flows of ...