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

Now showing items 601-620 of 1036

    • Article  

      Synthesis, Crystallographic Studies, and Characterization of K 2Bi8Se13-xSx Solid Solutions 

      Kyratsi, Theodora; Kanatzidis, M. G. (2003)
      The detailed crystal structures of selected members of solid solutions of the thermoelectric compounds K2Bi8Se13-xS x with x = 4, x = 6 and x = 10 were determined. The purpose of this study was to understand the nature of ...
    • Article  

      Thermoelectric properties of hot-pressed β-K2Bi 8Se13-x Sx materials 

      Kyratsi, Theodora; Ioannou, M. (2013)
      In this work, hot-pressed pellets of the K2Bi8Se 13 family of compounds were prepared for the first time. The pellet fabrication of selected members of the K2Bi8Se 13-x Sx series was studied. Sintering parameters, such as ...
    • Article  

      Changes in the electronic properties of Bi2X3 (X: Se, Te) single crystals due to intercalation 

      Kyratsi, Theodora; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Chrissafis, K. (1997)
      Bi2Se3 and Bi2Te3 are layered semiconductors n-type and p-type, respectively, which belong to the family of thermoelectric materials. In this work we examine the insertion of Cu in Bi 2Te3 and Bi2Se3 single crystals through ...
    • Article  

      Structure inhomogeneities, shallow defects, and charge transport in the series of thermoelectric materials K2Bi8-xSb xSe13 

      Kyratsi, Theodora; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Malliakas, C. D.; Dyck, J. S.; Uher, C.; Kanatzidis, M. G. (2006)
      The charge transport properties of the low-dimensional thermoelectric materials K2 Bi8-x Sbx Se13 (0<x≤8) were studied as a function of temperature and composition. The Seebeck coefficient shows an evolution from n - to p ...
    • Article  

      Synthetic conditions and their doping effect on β-K2Bi8Se13 

      Kyratsi, Theodora; Kika, I.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Chrissafis, K.; Kanatzidis, M. G. (2009)
      In this work the synthetic conditions for K2Bi8Se13 and their effect on its thermoelectric properties were investigated. K2Bi8Se13 was prepared as a single phase using K2Se and Bi2Se3 as starting materials in a furnace or ...
    • Conference Object  

      Synthesis, crystal structure and thermoelectric properties of β-K 2Bi 8Se 13 solid solutions 

      Kyratsi, Theodora; Chung, D. Y.; Dyck, J. S.; Uher, C.; Lal, S.; Loo, S.; Hogan, T.; Ireland, J.; Kannewurf, C. R.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, United StatesAffiliation: Department of Physics, University of Michigan, Ann Arbor, MI 48109, United StatesAffiliation: Department of Electrical Engineering, Michigan State University, East Lansing, MI 48824, United StatesAffiliation: Department of Electrical Engineering, Northwestern University, Evanston, IL 60208, United StatesAffiliation: Department of Physics, Aristotle University of Thessaloniki, 54006 Thessaloniki, GreeceCorrespondence Address: Kyratsi, T.Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States, 2003)
      Solid solution series of the type K 2Bi 8-xSb xSe 13, K 2-xRb xBi 8Se 13 as well as K 2B 18Se 13-xS x were prepared and the distribution of the atoms (Bi/Sb, K/Rb and Se/S) on different crystallographic sites, the band ...
    • Article  

      Optimization of thermoelectric properties of Bi2Se3 using insertion techniques 

      Kyratsi, Theodora; Hatzikraniotis, E.; Chrissafis, K.; Paraskevopoulos, K. M. (1998)
      In this work we investigate the optimization of the performance of thermoelectric materials using insertion techniques. Our results indicate that in cases such as Bi2Se3 compounds, where insertion of foreign species in the ...
    • Conference Object  

      Thermoelectric properties of K2Bi8-xSbxSe13 solid solutions and Se doping 

      Kyratsi, Theodora; Dyck, J. S.; Chen, W.; Chung, D. Y.; Uher, C.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, United StatesCorrespondence Address: Kyratsi, T.Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States, 2002)
      Our efforts to improve the thermoelectric properties of β-K2Bi8Se13, led to systematic studies of solid solutions of the type β-K2Bi8-xSbxSe13. The charge transport properties and thermal conductivities were studied for ...
    • Article  

      KSb5S8: A wide bandgap phase-change material for ultra high density rewritable information storage 

      Kyratsi, Theodora; Chrissafis, K.; Wachter, J.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (2003)
      The reversible glassformation and glass crystallization properties of KSb3S8 was described. On the basis of glass transition and crystallization kinetics of KSb5S8, it was found that the crystallization rate and assoicated ...
    • Conference Object  

      Crystal growth of ternary and quaternary alkali metal bismuth chalcogenides using Bridgman technique 

      Kyratsi, Theodora; Chung, D. Y.; Choi, K.-S.; Dick, J. S.; Chen, W.; Uher, C.; Kanatzidis, M. (Affiliation: Dept. of Chemistry, Center of Fundamental Mat. Research, Michigan State University, East Lansing, MI 48824-1322, United StatesCorrespondence Address: Kyratsi, T.Dept. of Chemistry, Center of Fundamental Mat. Research, Michigan State University, East Lansing, MI 48824-1322, United States, 2001)
      Our exploratory research in new thermoelectric materials has identified the ternary and quaternary bismuth chalcogenides β-K2Bi8Se13, K2.5Bi8.5Se14 and K1+xPb4-2xBi7+xSe15, to have promising properties for thermoelectric ...
    • Article  

      Thermoelectric properties and site-selective Rb+/K+ distribution in the K2-xRbxBi8Se13 series 

      Kyratsi, Theodora; Chung, D. Y.; Ireland, J. R.; Kannewurf, C. R.; Kanatzidis, M. G. (2003)
      β-K2Bi8Se13 possesses promising thermoelectric properties whereas Rb2Bi8Se13 does not. The formation of solid solutions between these two compounds was attempted to study the alkali metal distribution in the structure and ...
    • Article  

      Bi/Sb distribution and its consequences in solid solution members of the thermoelectric materials K2Bi8-xSbxSe13 

      Kyratsi, Theodora; Chung, D. Y.; Kanatzidis, M. G. (2002)
      In an effort to understand the nature of mass fluctuations introduced when β-K2Bi8Se13 is alloyed with K2Sb8Se13 we determined the detailed crystal structures of two solid solutions of the type K2Bi8-xSbxSe13 with x=4.0 ...
    • Conference Object  

      Thermoelectric materials and applications on the recovery of waste heat energy 

      Kyratsi, Theodora (Affiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678, Nicosia, CyprusCorrespondence Address: Kyratsi, T.Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678, Nicosia, Cyprus, 2010)
      Today, thermoelectric (TE) technology offers a solution regarding large amounts of energy that are lost as waste heat from various applications. In this paper, the need for better thermoelectric materials is addressed and ...
    • Article  

      Highly anisotropic crystal growth and thermoelectric properties of K 2Bi 8-xSb xSe 13 solid solutions: Band gap anomaly at low x 

      Kyratsi, Theodora; Dyck, J. S.; Chen, W.; Chung, D. Y.; Uher, C.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (2002)
      The thermoelectric properties of solid solutions of the type β-K 2Bi 8-xSb xSe 13 (0<x<8) were studied with respect to thermal behavior, band gap variation, and charge transport properties as a function of x. At x values ...
    • Conference Object  

      Vibration Measurement of Occupational Exposed Workers, Experimental Quantification of the Individual Response Parameters for the Estimation of Uncertainty in the Vertical Direction 

      Kyprianou, Andreas; Vazouras, A. (American Society of Civil Engineers (ASCE), 2014)
      The exposure of seated people to whole body vibration has been extensively researched and modelled during the past two decades. The trend is to use the average biodynamic responses. This paper investigates the relation of ...
    • Article  

      Identification of hysteretic systems using the differential evolution algorithm 

      Kyprianou, Andreas; Worden, K.; Panet, M. (2001)
      A widely used model in the field of hysteretic or memory-dependent vibrations is that of Bouc and Wen. Different parameter values extend its use to various areas of mechanical vibrations. As a consequence an identification ...
    • 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  

      Structural modification. Part 2: Assignment of natural frequencies and antiresonances by an added beam 

      Kyprianou, Andreas; Mottershead, J. E.; Ouyang, H. (2005)
      In this paper the inverse structural modification problem is solved in order to determine the dimensions of the cross-section of a beam that when added to an original structure will assign natural frequencies or antiresonances ...
    • Article  

      Assignment of natural frequencies by an added mass and one or more springs 

      Kyprianou, Andreas; Mottershead, J. E.; Ouyang, H. (2004)
      The problem of assigning natural frequencies to a multi-degree-of-freedom undamped system by an added mass connected by one or more springs is addressed. The added mass and stiffnesses are determined using receptances from ...
    • Conference Object  

      Choi-Wiliams time frequency analysis of a three degree freedom non-linear system 

      Kyprianou, Andreas; Staszewski, W.; Worden, K. (Katholieke Universiteit Leuven, 2006)
      The response of a non-linear mechanical oscillator, depending on the type of non-linearity, to an excitation of particular harmonic might contain sub- and super-harmonics, transients and chaotic components. The conventional ...