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Glass-ceramics in a dense and highly porous form can be obtained from metallurgical slag and waste glass of TV monitors. Using polyurethane foam as pore creator, a highly porous system with porosity of 65 ± 5 %, E-modulus and flexural strength of 8 ± 3 GPa and 13 ± 3.5 MPa respectively can be obtained. This porous material had durability (mass loss) of 0.03 % in 0.1 M HCl that is identical with the durability of a dense composite

Three types of composites consisting of Ca10(PO4)6(OH)2 and Ca3(PO4)2 with composition: 75% (wt) Ca10(PO4)6(OH)2: 25%(wt) Ca3(PO4)2; 50%(wt) Ca10(PO4)6(OH)2: 50%(wt)Ca3(PO4)2 and 25 %(wt) Ca10(PO4)6(OH)2: 75%(wt) Ca3(PO4)2 were the subject of our investigation. Sintered compacts were in thermal equilibrium, which was proved by the absence of hysteresis effect of the dependence ΔL/L=f(T) during heating /cooling in the temperature interval 20-1000-200C. Sintered compacts with the previously mentioned composition possess 26-50% higher values of the E-modulus, G-modulus and K-modulus indicating the presence of a synergism effect. Several proposed model equations for predicting the thermal expansion coefficient in dependence of the thermal and elastic properties of the constitutive phases and their volume fractions, given by: Turner, Kerner, Tummala and Friedberg, Thomas and Taya, were used for making correlations between mechanical and thermal-expansion characteristics of the Ca10(PO4)6(OH)2 - Ca3(PO4)2 composites. Application of the previously mentioned model equations to all kinds of composites leads to the conclusion that the experimentally obtained results for the thermal expansion coefficient are in an excellent agreement with the theoretical calculated values on account of the volume fraction of each constitutive phase and with all applied model equations, with a coefficient of correlation from 98.16-99.86 %

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Glass-ceramics were produced utilizing fly-ash from coal power stations and waste glass of TV monitors, windows and flask glass. The powder technology route was employed. The mixture of 50% fly ash and 50% waste TV glass increases the bending strength from 12±1 to 56±4 MPa and E-modulus from 6±1 to 26±3 GPa. Using polyurethane foam and C-fibers as pore creators porosity of 70±4 and 55±5 %, respectively, can be obtained-modulus and bending strength of the porous systems obtained by polyurethane foam and C-fibers was 2.7±0.5 GPa and 4.5±1 MPa and 7.1±1 GPa and 9.3±2 MPa respectively

Ebonex CoHydrogen evolution Oxygen evolution a b s t r a c tThe subject of this work is the use of non-stoichiometric titanium oxides e Magneli phases as support material of Co-based electrocatalysts aimed for hydrogen/oxygen evolution reaction. Commercial micro-scaled Ebonex (Altraverda, UK) was mechanically treated for 4, 8, 12, 16 and 20 h and further Co metallic phase was grafted by sol-gel method.Morphology of Co/Ebonex electrocatalysts was observed by means of TEM and SEM microscopy, while electrochemical behavior by means of cyclic voltammetry and steadystate galvanostatic method.As the duration of mechanical treatment increases, the size of Magneli phases decreases, and consequently catalytic activity of the corresponding electrocatalysts increases.Structural characteristics of the electrocatalysts deposited on Ebonex treated for 16 and 20 h are very similar. Also, these electrocatalysts show similar electrocatalytic activity for both hydrogen and oxygen evolution reaction. So, optimal duration of mechanical treatment of Magneli phases is in the range of 16e20 h.Catalytic activity for hydrogen evolution of the studied electrocatalysts is inferior related to the corresponding catalysts deposited on carbonaceous support materials such as activated multiwalled carbon nanotubes or Vulcan XC-72 þ TiO 2 (anatase). This inferiority is due to lower real surface area of the Magneli phases.Catalytic behavior for oxygen evolution achieves its maximal value even at the catalyst deposited on Ebonex treated for 12 h and it is very promising related to the similar electrocatalytic system such as CoPt/Ebonex. ª 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved. IntroductionRecent intensive development of hydrogen economy as an alternative energy system in the future imposes invention and research on new effective electrode materials. The modern electrode materials are composed of nanostructured catalytic phase dispersed over the support material that has to possess several very important characteristics, such as: i) highly developed surface area to provide better dispersion of the nano-scaled catalytic particles; ii) high electric conductivity to allow efficient electron transfer to ions involved in the electrochemical reactions, iii) mechanical and chemical stability and iv) to improve intrinsic catalytic activity of the active catalytic phase through the strong metalesupport interaction (SMSI) [1,2]. Carbon nanostructured materials such as carbon blacks are commercially the most used support material [3,4], * Corresponding author. Tel./fax: þ389 2 3064 392. E-mail address: pericap@tmf.ukim.edu.mk (P. Paunovi c).A v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / h e i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 5 ( 2 0 1 0 ) 1 0 0 7 3 e1 0 0 8 0

Conservation and restoration of cultural heritage are the objects of great interest worldwide. For setting the correct methodology for the procedures of the restoration it is very important to have the right information about the state of the object and the characteristics of the original materials. The basis of our examinations were clay products (samples of bricks, terracotta and clay roof tile) from the middle ages, the fortress in Bac. The following methods were used: x-ray diffraction, classic chemical analysis, SEM-EDS, Hg-porosimetry and dilatometry. Based on the used methods, mineral composition, temperature and regime of firing and textural properties of the examined materials were determined. The degree of destruction of examined materials was also identified, in order to find compatible materials for future techniques of conservation and restoration.

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