• Article  

      Tribological properties of twin electron-beam evaporated Cr-N and Al-Cr-N coatings under laboratory sliding and drill experiments 

      Polychronopoulou, K.; Demas, N. G.; Rebholz, Claus; Polycarpou, A. A. (2008)
      The tribological behavior of substoichiometric Cr-N and Al-Cr-N coatings prepared by twin electron-beam evaporation at 450°C was studied. Al-Cr-N coatings with Al to Cr ratios in the range of 1-8 (and nitrogen concentrations ...
    • Article  

      Tunneling in Pb-YBCO junctions: Determining the symmetry of the pairing state 

      Wollman, D. A.; Harlingen, D. J. Van; Giapintzakis, John; Ginsberg, D. M. (1995)
      We report on our efforts to understand the origin of supercurrent observed in c-axis tunnel junctions on YBCO [Sun A. G. et al., Phys. Rev. Lett. 72, 2267 (1994).] by studying the phase coherence of a-axis/c-axis and ...
    • Article  

      A two-dimensional numerical study of the stick-slip extrusion instability 

      Taliadorou, E.; Georgiou, G. C.; Alexandrou, Andreas N. (2007)
      The time-dependent, compressible extrusion of a Carreau fluid is solved over the reservoir-die-extrudate region using finite elements in space and a fully implicit scheme in time. A nonmonotonic slip law based on experimental ...
    • Conference Object  

      A two-phase fluid model of crystal settling under variable gravity 

      Alexandrou, Andreas N.; Shi, H.; Gatsonis, N. A.; Jr, A. Sacco (American Institute of Aeronautics and Astronautics Inc, AIAA, 1999)
      A two-phase fluid model of crystal particle motion in a liquid is presented. The model includes a liquid and a solid phase as continua and forces due to pressure, viscous stresses, variable gravity and fluid drag. The model ...
    • Conference Object  

      Two-phase model for processing materials in semisolid state 

      Alexandrou, Andreas N.; Burgos, Gilmer R.; Entov, Vladimir (Affiliation: Worcester Polytechnic Inst, Worcester, United StatesCorrespondence Address: Alexandrou, Andreas N.Worcester Polytechnic Inst, Worcester, United States, 1998)
      The importance of processing of metal and metal matrix composites in semisolid state is increasing quite rapidly due to the distinct advantages it offers over similar methods of near-net-shape making. In this investigation ...
    • Article  

      Ultrafast carrier relaxation in inn nanowires grown by reactive vapor transport 

      Othonos, A.; Zervos, Matthew; Pervolaraki, M. (2009)
      We have studied femtosecond carrier dynamics in InN nanowires grown by reactive vapor transport. Transient differential absorption measurements have been employed to investigate the relaxation dynamics of photogenerated ...
    • Article  

      Ultrafast hole carrier relaxation dynamics in p-type CuO nanowires 

      Othonos, A.; Zervos, Matthew (2011)
      Ultrafast hole carrier relaxation dynamics in CuO nanowires have been investigated using transient absorption spectroscopy. Following femtosecond pulse excitation in a non-collinear pump-probe configuration, a combination ...
    • Article  

      Ultrafast pulsed laser deposition of carbon nanostructures: Structural and optical characterization 

      Pervolaraki, M.; Komninou, P.; Kioseoglou, J.; Othonos, A.; Giapintzakis, John (2013)
      Carbon nanostructured materials were obtained by high-repetition rate pulsed laser ablation of a graphite target using a train of 10-ps duration pulses at 1064 nm in different pressures of high-purity Ar gas. It is ...
    • Article  

      Ultrafast Spectroscopy and Red Emission from β-Ga2O3/β-Ga2S3 Nanowires 

      Othonos, K. M.; Zervos, Matthew; Christofides, C.; Othonos, A. (2015)
      Ultrafast pump-probe and transient photoluminescence spectroscopy were used to investigate carrier dynamics in β-Ga2O3 nanowires converted to β-Ga2O3/Ga2S3 under H2S between 400 to 600 °C. The β-Ga2O3 nanowires exhibited ...
    • Article  

      Ultrafast time-resolved spectroscopy of In2 O3 nanowires 

      Tsokkou, D.; Othonos, A.; Zervos, Matthew (2009)
      Ultrafast carrier dynamics in In2 O3 nanowires with an average diameter of ≈100±20 nm grown by the vapor-liquid-solid method have been investigated in detail using differential absorption spectroscopy with femtosecond ...
    • Article  

      Ultrafast transient spectroscopy and photoluminescence properties of V 2O5 nanowires 

      Othonos, A.; Christofides, C.; Zervos, Matthew (2013)
      The properties of V2O5 semiconductor nanowires have been investigated using ultrashort transient absorption spectroscopy in conjunction with time resolved photoluminescence. Femtosecond pulse excitation has been utilized ...
    • Article  

      Ultrasonic consolidation and ignition characteristics of thermite composites 

      Pillai, S. K.; Hadjiafxenti, A.; Doumanidis, C. C.; Ando, T.; Rebholz, Claus (2012)
      The fabrication and characterization of metal-based energetic composite materials are currently being examined for a range of new applications. A newly developed ultrasonic consolidation process is used for the synthesis ...
    • Article  

      Ultrasound Contrast Imaging Research 

      Averkiou, Michalakis A.; Powers, Jeff; Skyba, Dan; Bruce, Matthew; Jensen, Seth (2003)
      This article is a review of the research on ultrasound contrast agents in general imaging. While general imaging contrast agent applications are still undergoing investigation and waiting FDA approval in the United States, ...
    • Article  

    • Book Chapter  

      Ultrasound imaging modalities 

      Mischi, M.; Rognin, N. G.; AVERKIOU, MICHALAKIS A. (Elsevier, 2014)
      After a short introduction on generation and propagation of ultrasound waves, this chapter presents and discusses currently available and emerging ultrasound imaging modalities, such as standard modes in one, two, and three ...
    • Article  

      Ultraviolet emission from low resistance Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires 

      Karageorgou, E.; Zervos, Matthew; Othonos, A. (2014)
      SnO2 and Sn:In2O3 nanowires were grown on Si(001), and p-n junctions were fabricated in contact with p-type Cu2S which exhibited rectifying current-voltage characteristics. Core-shell Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 ...
    • Conference Object  

      Uncertain systems: Modelling and updating 

      Kyprianou, Andreas; Mottershead, J. E. (Affiliation: Departament of Mechanical and Manufacturing Engineering, University of Cyprus, 1678, Nicosia, PortugalAffiliation: Department of Engineering, University of Liverpool, L69 3GH, Liverpool, United KingdomCorrespondence Address: Kyprianou, A.Departament of Mechanical and Manufacturing Engineering, University of Cyprus, 1678, Nicosia, Portugalemail: akyp@ucy.ac.cy, 2011)
      In this article a new method, which relies on the concept of density matrix, for modelling un- certain vibrating structures is presented. The density matrix is defined as the product of the normalized to unity mode shape ...
    • Article  

      Unconventional magnetism in all-carbon nanofoam 

      Rode, A. V.; Gamaly, E. G.; Christy, A. G.; Gerald, J. G. Fitz; Hyde, S. T.; Elliman, R. G.; Luther-Davies, B.; Veinger, A. I.; Androulakis, J.; Giapintzakis, John (2004)
      We report production of nanostructured magnetic carbon foam by a high-repetition-rate, high-power laser ablation of glassy carbon in Ar atmosphere. A combination of characterization techniques revealed that the system ...
    • Article  

      Understanding the mechanical and thermal property reinforcement of crosslinked polyethylene by nanodiamonds and carbon nanotubes 

      Roumeli, E.; Avgeropoulos, A.; Pavlidou, E.; Vourlias, G.; Kyratsi, Theodora; Bikiaris, D.; Chrissafis, K. (2014)
      A comprehensive investigation of the mechanical and thermal property reinforcement of silane-crosslinked polyethylene nanocomposites, containing small amounts of multi-walled carbon nanotubes (MWCNTs) and nanodiamonds ...
    • Conference Object  

      Uniaxial and biaxial mechanical behavior of human amnion 

      Barocas, V. Η; Oyen, M. L.; Stylianopoulos, T.; Calvin, S. E.; Cook, R. F. (Affiliation: Department of Biophysical Sciences and Medical Physics, University of Minnesota, Minneapolis, MN 55455, United StatesAffiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, United StatesAffiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, United StatesAffiliation: Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, MN 55455, United StatesAffiliation: Minnesota Perinatal Physicians/Allina Health System, Minneapolis, MN 55407, United StatesCorrespondence Address: Oyen, M.L.Department of Biophysical Sciences and Medical Physics, University of Minnesota, Minneapolis, MN 55455, United States, 2005)
      Chorioamnion, the membrane surrounding a fetus during gestation (the "amniotic sac"), is a structural soft tissue for which the mechanical behavior is poorly understood-despite its critical role in maintaining a successful ...