Proceedings 11-18

THEORETICAL FUNDAMENTALS OF CALORIMETRY

Jindřich Leitner

Department of Solid State Engineering, Institute of Chemical Technology, Technická 5, 366 28 Prague 6, Czech Republic, jindrich.leitner@vscht.cz

The contribution gives in brief the outline of theoretical basis of calorimetry – thermochemistry and the heat transfer theory. Selected calorimetric techniques for determination of heat capacity, heat of reactions, and heats of solution are described.

Key words: Calorimetry; Thermochemistry; Heat transport; Heat capacity; Heat of formation

Proceedings 21-23

MEASUREMENT OF HEAT CAPACITIES ON TA Q1000 CALORIMETER

Martin Růžička, Květoslav Růžička, Pavel Vrbka

Dept. Phys. Chemistry, Institute of Chemical Technology, Technická 5, 166 28 Prague 6, Czech Republic, ruzickak@vscht.cz

Different aspects affecting measurement of heat capacities by DSC were studied experimentally. Results for calorimeter TA Q1000 are presented along with general recommendations and uncertainties caused by using simple and less time-consuming methods.

Keywords: Heat capacity; DSC; Calibration

Proceedings 25-28

HIGH TEMPERATURE HEAT CAPACITY OF ND₂ZR₂O₇ AND LA₂ZR₂O₇ PYROCHLORES

O. Beneš ^A, D. Sedmidubský ^A, R.J.M. Konings ^B

^A Institute of Chemical Technology, Technická 5, 166 28 Prague, Czech Republic, ondrej123@centrum.cz

^B European Commission, JRC, Institute for Transuranium Elements, P,O. Box 2340, D-76125 Karlsruhe, Germany

The enthalpy increment measurements were performed using drop calorimetry on two lanthanide zirconates Ln₂Zr₂O₇, Ln = La, Nd, with pyrochlore structure. The temperature dependence of heat capacity in range (298 to 1550) K was derived by simultaneous linear regression of the measured enthalpies combined with the heat capacity data around ambient temperature. The obtained heat capacity C_p (T) is compared to the limit of constant volume lattice C_v calculated from the analysis of low temperature specific heat data using a combined Debye-Einstein harmonic approximation model.

Keywords: Lanthanide pyrochlores; Drop calorimetry; Enthalpy; Heat capacity; Setaram HTC calorimeter

Proceedings 29-32

HEAT CAPACITIES OF NA₂SO₄ AND K₂SO₄

Galina Sádovská , Lucie Kourková

Univerzita Pardubice, Fakulta chemicko-technologická, Katedra anorganické technologie, nám. Čs. legií 565, 532 10 Pardubice, Czech Republic, galina.sadovska@upce.cz

Heat capacities of Na₂SO₄ and K₂SO₄ were measured at constant pressure by using C80 heat flow calorimeter (Setaram). Experimental data of heat capacities were measured over the temperature range from 303.15 to 563.15 K with respect to thermal stability of studied compounds. The corresponding thermodynamic values (enthalpy, entropy) are calculated from determined heat capacities.

Keywords: Calorimetry; Heat capacity; Sodium sulphate; Potassium sulphate.

Proceedings 33-36

PHASE EQUILIBRIA AND THERMODYNAMICS OF THE CA-CE-MG SYSTÉM

Milan Hampl, Joachim Groebner, Rainer Schmid-Fetzer

Technical University of Clausthal, Institute of Metallurgy, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld, Germany, milan.hampl@tu-clausthal.de

The ternary Ca-Ce-Mg phase equilibria were investigated using scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX) and differential scanning calorimetry (DSC). Key experiments were selected using preliminary thermodynamic calculations with focus on Mg-rich corner. A consistent thermodynamic description was developed using Calphad method with new experimental results. Calculated vertical section and liquidus projection are presented.

Keywords: Phase diagram Ca-Ce-Mg; Thermodynamic modeling; Calphad

Proceedings 37-40

THRESHOLD TEMPERATURE OF COAL OXIDATION- CALORIMETRIC VIEW

Boleslav Taraba, Rudolf Peter

Ostrava University, Department of Chemistry, 30. dubna 22, 70103 Ostrava, Czech Republic, boleslav.taraba@osu.cz

Methods of pulse flow calorimetry, inverse gas chromatography and oxidation in flow reactor were used to evaluate the temperature dynamics of coal oxidation. As quantifying parameters, activation energy E and threshold temperature of coal self-heating T_thr were determined. Activation energies E were found to be between 34 – 53 kJ/mol, threshold temperatures of coal self-heating T_thr varied from 45 to 100°C. Markedly lower values of T_thr from calorimetry (by 30°C) were found to be related with sample pretreatment before calorimetric investigation.

Key words: Coal oxidation; Activation energy; Calorimetry; Threshold temperature

Proceedings 41-44

Application aspects of thermal analyses in electrotechnology

Václav Mentlík, Radek Polanský,
Department of Electrotechnology, University of West Bohemia in Pilsen, Univerzitní 26, 306 14 Pilsen, Czech Republic, mentlik@ket.zcu.cz

The motivation leading to the application of thermal analyses in electrotechnology has been presented. The main aim is to obtain sufficient information about reactive particles condition, as well as about values of glass transition temperature and thermal expansion coefficients for materials used in production of electric machines.

Keywords: Electrotechnology; Enthalpy; Glass transition temperature; Thermal expansion coefficient; DTA; TMA; TGA

Proceedings 45-48

DEHALOGENATION OF POLYCHLORINATED BIPHENYLS

Michal Bureš^A, Vladimír Pekárek ^B

^A Department of Physical Chemistry, Institute of Chemical Technology, Technická 5, 16628 Prague, Czech Republic, michal.bures@vscht.cz

^B Institute of Chemical Process Fundamentals, Czech Academy of Sciences, Rozvojová 2, 16502 Prague, Czech Republic.

This work deals with the determination of the thermodynamic stability of di- to nona-chlorinated biphenyls during the dehalogenation process of these compounds in the gas phase by steam in presence of solid copper. The aim of this study is a preliminary calculation of chemical equilibrium in this dehalogenation process, which can be compared with the measured kinetics data, obtained during simulation of the technologic process. The work is connected with our previous studies, carried out with dehalogenation of polychlorinated benzenes¹ and polychlorinated phenols².

Keywords: Polychlorinated biphenyl; PCB; Dechlorination; Thermodynamics

Proceedings 51-59

The energy flows and balances in different eco-systems levels, IN agriculture and utilization of calorimetric methods for balancing

Zdeněk Strašil^A, Petr Homolka^B

^AVýzkumný ústav rostlinné výroby, Drnovská 507, Praha 6 – Ruzyně, Czech Republic, strasil@vurv.cz

^BVýzkumný ústav živočišné výroby, Přátelství 815, Praha 10 – Uhříněves, Czech Republic

In the contribution is described the Erth global energy balance, energy flows and balances in eco-systems and solar radiation utilization by plants. Further there are presented general energy balances in agriculture, energy flows and transformation in agriculture three sub-systems (crop production, animal production, soil) creating cyclic chain.

Keywords: Energy flows; Energy balances; Eco-systems; Agriculture

Proceedings 61-64

THE CONTENT OF NET ENERGY IN INDIVIDUAL ORGANS OF SUGAR BEET

František Hnilička¹, Jaroslav Urban², Josef Pulkrábek²

¹ Česká zemědělská univerzita v Praze, katedra botaniky a fyziologie rostlin, Kamýcká 129, 165 21 Praha 6 - Suchdol, Česká republika, hnilicka@af.czu.cz

² Česká zemědělská univerzita, katedra rostlinné výroby, Kamýcká 129, 165 21 Praha 6 - Suchdol, Česká republika

In the field experiments established in the years 2002 – 2004 we studied energy content by cultivars of suger -beet: Takt and Compass. At the cultivars Compass was the average combustion heat value 14,74 kJ.g^-1. By the cv. Takt we have found content of rich in energy matters 14,60 kJ.g^-1. The gathered results show, that the statistically not significant differences from among cultivars of suger-beet. The lowest amount of energy was found in footstalk (13,0 kJ.g^-1) and highest amount of energy was found in bulb of beet – 16,32 kJ.g^-1.

Keywords: Cultivar; Sugar-beet; Combustion enthalpy; Footstalk; Energy content

Proceedings 65-68

THE CONTENT OF ENERGY IN GENERATIVE AND VEGETATIVE HOP PLANT ORGANS

Helena Hniličková, František Hnilička

Česká zemědělská univerzita v Praze, katedra botaniky a fyziologie rostlin, Kamýcká 129, 165 21 Praha 6 - Suchdol, Czech Republic, hnilickova@af.czu.cz

In the experimental hop-garden of the hop Research Institute (Žatec) we studied energy content by the generative and vegetative hop plant organs. From all the studied organs, most of energy per 1 g dry matter was accumulated in leaves (15,93 kJ.g^-1). In the hop bine was accumulated 14,50 kJ.g^-1 energy and in the hop cones was accumulated 14,98 kJ.g^-1 energy.

Keywords: Hop; Leave; Bine; Combustion enthalpy; Energy content

Proceedings 69-72

THE CHANGES OF ENERGY’S TRANSLOCATION IN ALTERNATIVE VARIETIES OF WHEAT DURING ONTOGENY

Jaroslava Martinková¹, František Hnilička¹, Helena Hniličková¹, Jiří Petr²

¹ Česká zemědělská univerzita v Praze, katedra botaniky a fyziologie rostlin, Kamýcká 129, 165 21 Praha 6 - Suchdol, Czech Republic, martinkova@af.czu.cz

² Česká zemědělská univerzita, katedra rostlinné výroby, Kamýcká 129, 165 21 Praha 6 - Suchdol, Czech Republic

In the field experiments established in the years 2001 – 2004 we studied energy content by cultivars of alternative varieties of wheat: Anemos, Velos, Česká přesívka and Postoloprtská přesívka. Between varieties there is a statistical difference (lowest content was found Česká přesívka -13,42 kJ.g^-1 and highest content of energy was found Velos -13,95 kJ.g^-1). The lowest amount of energy was found in blade (13,05 kJ.g^-1) and leaves (13,67 kJ.g^-1). The highest amount of energy was found in grains – 14,57 kJ.g^-1.

Keywords: Alternative varieties; Wheat; Net energy; Leaves; Grains

Proceedings 73-76

ENERGY CONTENT IN THE PHYTOMASS OF CAREX PILOSA SCOP. SPECIES IN REGION OF THE STARA PLANINA MTS (BULGARIA)

Margita Kuklová, Ján Kukla

Ústav ekológie lesa SAV, Štúrova 2, 960 53 Zvolen, Slovak Republic, kuklova@sav.savzv.sk

The research was focussed on assessment of ecological character of beech ecosystems and variability of phytoparameter values of the dominant herb layer species – Carex pilosa Scop. It was carried out in July 2004 on four monitoring plots – Bukaka (435 m a.s.l., leached Chromi-Rendzic Leptosol, limestone), Boáza (450 a.s.l., Luvi-Dystric Cambisol, shale), Zelenič (710 m a.s.l., Skeli-Dystric Cambisol, sandstone) and Karandila (1100 m a.s.l., Dystric Cambisol, sandstone) in the E part of the Stará planina Mts. (Bulgaria). The studied geobiocoenoses belong to the groups of forest types (gft) Fagetum pauper inferiora – the forest type (ft) Carex pilosa nudum (Bukaka, Boáza), Fagetum pauper superiora – ft Carex pilosa nudum, Prenanthes purpurea (Karandila) and gft Fagetum typicum – ft Carex pilosa, Festuca drymeja, Prenanthes purpurea (Zelenič). The lower average weight (0.357 – 0.374 g) and energy content (18 009 -18 134 J.g^-1 of dry matter, 6 429 - 6 782 J per shoot) in the sedge phytomass were found in ecosystems of the 3^th forest vegetation tier (fvt) (Boáza, Bukaka), the higher values (0.437 – 0.493 g, 18 260 - 18 671 J.g^-1 of dry matter, 7 980 - 9 205 J per shoot) were in ecosystems of the 4^th fvt (Zelenič, Karandila). The ash content in phytomass of sedge was, on the other hand, higher in the 3^th fvt, with an absolute maximum in mesotrophic geobiocoensis (Bukaka – 12.1 %, Boáza – 11.6 %, Zelenič – 8.2 %, Karandila – 10.1 %).

Keywords: Beech ecosystems; Soils; Carex pilosa; Energy content; Stara planina Mts

Proceedings 77-80

Calorimetric study of dormant apple buds

Alois Bilavčík^A, Jiří Zámečník^A, Jaroslav Šesták^B

^A Research Institute of Crop Production, Drnovská 507,161 06 Prague 6 - Ruzyně, CZ, bilavcik@vurv.cz

^B Institute of Physics, Academy of Sciences, Cukrovarnicka 10, CZ-162 53 Prague 6, CZ

This work deals with thermal characteristics of dormant apple buds. It was found that the inner part of the dormant apple bud collected from naturally frozen potted plant is in the glassy state, although the bark tissues are responsible for the crystallization events. Results suggest that dormant apple buds survive low temperatures in the glassy state.

Keywords: Apple buds; Glassy state; Freezing

Proceedings 81-84

THERMAL ANALYSIS OF PLANT SEEDS WITH LOW STORAGE STABILITY

Jiří Zámečník^A, Eva Černošková^B, Antonín Sikora^C, Iva Faberová^A

^AResearch Institute of Crop Production, Drnovská 507, Prague 6, CZ 161 06, zamecnik@vurv.cz

^BUniversity of Pardubice, Studentská 84, Pardubice, CZ 532 10

^CInstitute of Macromolecular Chemistry, Academy of Science of Czech Republic, Heyrovský sq.2, Prague 6, CZ 162 06

Thermal analysis is a method suitable for identification of thermal changes in seeds of vegetables and ornamental plants during their storage at low temperatures. Heat flow measurement during cooling and warming of the seeds shows endo- and exo-thermal reactions. In seeds of chives (Allium schoenoprasum L., cv. Pražská) two endothermic peaks of two endothermic events were found. The glass transition during freezing and thawing was better distinguishable by quasi-isothermal modulation of temperature. By this method it was possible to distinguish dramatic changes of the heat capacity at approximately -18 °C representing glass transition in chives seeds during warming. Further experiments are need for full scale explanation.

Keywords: Differenttial scanning calorimetry; Seed; Storage

Proceedings 85-88

THE STUDY OF WATER CONTENT IN CHIVE AND RADISH DEPENDING ON RELATIVE HUMIDITY

Eva Černošková^A, Vítězslav Zima^A, Jiří Zámečník^B

^AJoint Laboratory of Solid State Chemistry of Institute of Macromolecular Chemisty of Czech Academy of Sciences and University Pardubice, Studentská 84, Pardubice, Czech Republic, eva.cernoskova@upce.cz

^BResearch Institute of Crop Production, Drnovská 507, Prague 6 - Ruzyně, Czech Republic

Water content in chive and radish seeds was studied by DSC and TG. The seeds were kept for 24 days at room temperature in relative humidity 75 %. DSC and TG were measured every day during this time. From DSC it was found that activation energy of dehydration for chive was E = 53 ± 12 kJ/mol and for radish E = 88 ± 6 kJ/mol. Obtained values are in the interval of data published for adsorbed water. From TG measurements follows that adsorbed water content gradually increases until 140 ^oC, in accordance with DSC measurements, and in seeds of Prague Chive is 12,5 wt % of water (7,5 wt % intrinsical water, 5,2 wt % adsorbed one). Seeds of radish Mária contain 7,8 wt % of water (4,6 wt % intrinsical water, 3,2 wt % adsorbed one). It was found also that chive is able to adsorb more water that radish and kinetics of dehydration is very similar for all off seeds.

Keywords: Seeds; Dehydration; Differential scanning calorimetry; Thermogravimetry

Proceedings 91-98

GLASSY STATE

Zdeněk Černošek^A, Jana Holubová^A, Eva Černošková^B, Marek Liška^C, Mária Chromčíková^C

^ADepartment of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, nám. Legií 565, Pardubice, Czech Republic, zdenek.cernosek@upce.cz

^BJoint Laboratory of Solid State Chemistry of Institute of Macromolecular Chemisty of Czech Academy of Sciences and University Pardubice, Studentská 84, Pardubice, Czech Republic.

^CVitrum Laugaricio (VILA) - Joint Glass Center of Institute of Inorganic Chemistry SAS, Alexander Dubček University of Trenčín and RONA Lednické Rovne, Študentská 2, Trenčín, Slovak Republic.

Processes at temperatures below crystal melting temperature are briefly described. Four of possible basic models of the glass transition are summarized – thermodynamic phase transformation, entropic model, model of relaxation kinetics and free-volume model. Up to date experimental results are mentioned and confronted with widely used opinion that glass is only a kinetically "frozen" undercooled melt. It comes out that this point of view needn't be fully in accord with reality.

Keywords: Glass transition; Glass; Relaxation; Entropy; Kauzmann paradox; DSC

Proceedings 99-102

MULTI RESPONSE REGRESSION ANALYSIS OF ENTHALPY RELAXATION DSC DATA

Marek Liška^A, Mária Chromčíková^A, Štefan Valovič^B, Zdeněk Černošek^C

^A Centrum kompetencie skla Vitrum Laugaricio, spoločné pracovisko Ústavu anorganickej chémie SAV, Trenčianskej univerzity Alexandra Dubčeka a RONA, a.s., Študentská 2, Trenčín, SK-911 50,  liska@tnuni.sk

^B Katedra fyziky, Univerzita Konštantína Filozofa, Trieda A. Hlinku 1, Nitra, SK-949 74, e‑mail: svalovic@ukf.sk

^C Katedra obecné a anorganické chemie, Fakulta chemicko-technologická, Univerzita Pardubice, Náměstí legií 565, Pardubice, CZ-532 10, zdenek.cernosek@upce.cz

Heat capacities of 15Na₂O.xMgO.(10–x)CaO.75SiO₂ glasses were measured in temperature range from 400°C to 650°C with various heating rates. Stability of the specific isobaric heat capacities of glass and meta-stable equilibrium melt with respect to the heating rate applied during the DSC experiment was verified. While the value of the glass heat capacity is relatively stable those of meta-stable equilibrium melt exhibited significant variation. Obtained results give the guidelines for the determination of the set of optimized parameters for the proposed multi response (simultaneous) regression analysis of a set of DSC curves obtained by various heating rates.

Keywords: Glass; Enthalpy relaxation; Heat capacity, DSC

Proceedings 103-106

THERMOANALYTICAL STUDY OF ZINC BOROPHOSPHATE GLASSES.

Jiří Schwarz, Josef Jirák, Petr Mošner, Ladislav Koudelka, Helena Tichá

Katedra obecné a anorganické chemie, Univerzita Pardubice, Fakulta chemicko-technologická, 532 10 Pardubice, Czech Republic, jiri.schwarz@upce.cz

Thermal behavior of glasses of the series 50ZnO-xB₂O₃-(50-x)P₂O₅ (x=0-25 mol.% B₂O₃) was studied by thermomechanical analysis and differential thermal analysis in the DSC mod. DSC curves revealed that most studied glasses crystallize on heating in the range of 454-679°C. Glass transition temperature increases with increasing B₂O₃ content from 397°C for 50ZnO-50P₂O₅ up to 514°C for the glass with 20 mol.% B₂O_3, whereas the coefficient of thermal expansion decreases. Moreover, the effect of experimental parameters on the accuracy of the determination of parameters obtained from TMA curves was investigated and discussed.

Keywords: TMA; DTA; Glasses; Borophosphates

Proceedings 107-110

THERMAL BEHAVIOR OF ZNO-B₂O₃-P₂O₅ +TIO₂ GLASSES

Petr Mošner, Ladislav Koudelka, Jaroslav Pospíšil

Katedra obecné a anorganické chemie, Univerzita Pardubice, Fakulta chemicko-technologická, 53210 Pardubice, Czech Republic, petr.mosner@upce.cz

It was studied thermal behavior of glasses in compositional series 50ZnO-10B₂O₃-40P₂O₅+xTiO₂, where x = 0-64 mol% TiO₂. From the DSC curves it was found that all glasses crystallize on heating in the temperature region 576-670^oC. At the glasses containing 24 and 56 mol% TiO₂ were investigated the mechanism of nucleation. It was found that in the both cases the surface nucleation is prevailing process. TMA analysis revealed that the glass transformation temperature increase with increasing TiO₂ content from 483^oC in the case 50ZnO-10B₂O₃-40P₂O₅ glass to 560^oC in the case of glass, where x = 64mol% TiO₂. The thermal expansion coefficient decreases in dependence on TiO₂ content. The highest thermal stability possess the glasses where x =12 and 56mol% TiO_2.

Keywords: Glasses; Borophosphates; Titanium oxide; Thermal behavior

Proceedings 111-114

Crystal growth of Sb₂S₃ in chalcogenide glass (ges₂)_0.3 (sb₂s₃)_0.7

Daniel Švadlák^A, Milan Vlček^B, Jiří Málek^A

^A Katedra fyzikální chemie, Fakulta chemicko-technologická, Univerzita Pardubice, nám. Čs. Legií 565, Pardubice 532 10, daniel.svadlak@upce.cz

^B Společná laboratoř chemie pevných látek a Ústavu makromolekulární chemie AVČR a Univerzity Pardubice

The crystallization kinetics in (GeS₂)_0.3 (Sb₂S₃)_0.7 glass was studied by differential scanning calorimetry under non-isothermal and isothermal conditions. The crystallization effect detected with XRD was recognized as crystallization of Sb₂S₃. The samples were prepared in powder and bulk form. Crystallization of powder and bulk samples were described using SB(M,N) model and JMA(n) model, respectively. The size of needle shaped Sb₂S₃ crystals was studied by electron microscopy. From this linear time dependence of Sb₂S₃ crystal length was determined the crystal growth rate for temperature 310 °C.

Keywords: System Ge-Sb-S; Kinetic study; DSC; Crystallization; Chalcogenide glasses

Proceedings 117-124

THERMAL AND HYGRIC PROPERTIES OF BUILDING MATERIALS

Robert Černý

CTU in Prague, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech republic, cernyr@fsv.cvut.cz

Basic heat and moisture transport and storage parameters in building materials, the methods of their definition and basic methods for their determination are described in the paper.

Keywords: Thermal parameters; Hygric parameters; Building materials

Proceedings 125-128

WATER AND SALT TRANSPORT IN CAST GYPSUM

Zbyšek Pavlík^a, Pavla Rovnaníková^b, Robert Černý^a

^aČVUT v Praze, Stavební fakulta, katedra stavební mechaniky, Thákurova 7, 166 29 Prague 6, Czech Republic, cernyr@fsv.cvut.cz

^bVUT v Brně, Stavební fakulta, Ústav chemie, Žižkova 17, 602 00Brno, Czech Republic

Basic models of coupled water and salt transport in building materials are presented in the paper. The methods for determination of water and salt transport parameters are analyzed, and their application illustrated on the example of calculation of moisture diffusivity and salt diffusion coefficient from the moisture and salt concentration profiles measured for cast gypsum

Keywords: Water transport; Salt transport; Moisture diffusivity; Ion diffusivity

Proceedings 129-132

THE EFFECT OF HYDROPHOBIZATION ON HYGROTHERMAL CONDITIONS IN BUILDING ENVELOPES ON THE BASIS OF CAST CALCINED GYPSUM

Jiří Maděra, Pavel Tesárek, Robert Černý,

Czech Technical University, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech Republic, cernyr@fsv.cvut.cz

A computational analysis of the effect of gypsum hydrophobization on the hygrothermal conditions in building envelopes based on cast gypsum elements is presented in the paper. For the heat and moisture transport problem solution, the computer code DELPHIN 4 is applied. Temperature, relative humidity and moisture content are calculated for the time period of 5 years. An analysis of the influence of initial conditions is performed as well.

Keywords: Calcined gypsum; Hydrophobization; Hygrothermal performance

Proceedings 133-136

EFFECT OF HIGH TEMPERATURES ON THERMAL PARAMETERS OF AN ALUMINOSILICATE COMPOSITE MATERIAL

Lucie Zuda¹, Jan Toman², Robert Černý¹

¹CTU in Prague, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech republic

²CTU in Prague, Faculty of Civil Engineering, Department of Physics, Thákurova 7, 166 29 Prague 6, Czech Republic, toman@fsv.cvut.cz

Thermal parameters of an alkali activated slag material at high temperatures are presented in the paper. Thermal conductivity, thermal diffusivity and specific heat capacity are determined in the temperature range from laboratory temperature up to 1200⁰C.

Keywords: Thermal parameters; High temperatures; Aluminosilicates

Proceedings 137-140

THE IMPACT OF THE FIBRE REINFORCEMENT ON THE THERMAL AND MECHANICAL PROPERTIES OF THE UNBURNT CLAY

Roman Vejmelka, Eva Mňahončáková, Jan Toman

Department of Physics, Faculty of Civil Engineering, CTU in Prague, Thakurova 7, 166 29 Prague 6, Czech Republic, roman.vejmelka@fsv.cvut.cz

The impact of the fibre reinforcement on the thermal and mechanical properties of mixtures made of unburnt clay was studied.

Keywords: Unburnet clay; Fiber reinforcement; Mechanical and thermal properties

Proceedings 141-144

Thermal degradation of meat and bone meal and its influence upon the reactivity of cement phases during the production of cement.

Martin Palou, Martin Dováľ and Eva Smrčková

Department of Ceramics, Glass and Cement, FCHPT, Radlinského 9, 812 37 Bratislava, Slovak Republic, martin.palou@stuba.sk

The thermal degradation of bone meal at different temperatures has led to the destruction of organic compounds, to the crystallization of Ca₁₀(PO₄)₆(OH)₂ at 800 °C and to its decomposition at higher temperatures. The present study is concerned by a model of interaction of C₂S with hydroxyapatite - Ca₁₀(PO₄)₆(OH)₂ during clinker firing. Ca₁₀(PO₄)₆(OH)₂ at great extent influences the reactivity of C₂S to form C₃S. The CaO of apatite substitutes CaO in C₂S, while P₂O₅ stabilizes C₂S by replacing SiO₂. This substitution of ions Ca²⁺ and Si⁴⁺ in C₂S by Ca²⁺ and P⁵⁺ of apatite enhances free lime content in cement and retards the formation of C₃S.

Keywords: Crystallization; Hydroxyapatite; Calcium silicate; Stabilization; Reactivity

Proceedings 145-148

HYDRAULIC ACTIVITY OF CEMENT PHASES SYNTHETIZED

BY SOL – GEL METHOD

Martin Dováľ and Martin Palou Department of Ceramics, Glass and Cement, FCHPT, Slovak University of Technology Bratislava, Radlinského 9, 812 37 Bratislava, Slovak Republic, martin.doval@stuba.sk

The sol-gel method was used to prepare the nano-crystalline phases of C₂AS and C₂S at ambient temperature following by firing at 600°C and 1100°C or 900°C during 1h. The effect of temperature on the hydration reaction of these phases has been investigated by means of isothermal conduction calorimeter. The microstructure of the samples cured under hydrothermal condition after 7 days has been examined by means of scanning microscope. Progress of crystallinity of C₂AS and C₂S were characterized by XRD analysis. An increase in the temperature of hydration brought about initial acceleration of all samples, as indicated by the increased magnitude of peak of calorimetric curves.

Keywords: Differential isoperbolic calorimeter; Hydration; Dicalcium silicate; Gehlenite

Proceedings 149-152

Nanoporosimetric Measurements on High Performance Concrete

Dita Stoklasová, Milena Jiřičková, Robert Černý

CTU in Prague, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech Republic, cernyr@fsv.cvut.cz

The porosity of solid and powder materials belonging to basic material parameters affects important physical properties such as mechanical strength, resistance and adsorption properties. The knowledge of porous structure makes possible to anticipate the properties of materials in various external conditions. In this paper, the results of measurements of total pore surface, total pore volume and pore distribution of high performance concrete using fully automatic analytical instrument SORPTOMATIC 1990 are presented.

Keywords: High Performance Concrete, Sorption, Nanopores

Proceedings 153-156

EFFECT OF THERMAL LOAD ON HYGRIC AND THERMAL PROPERTIES OF HIGH PERFORMANCE CONCRETE

Eva Mňahončáková¹, Milena Jiřičková², Robert Černý²

¹CTU in Prague, Faculty of Civil Engineering, Department of Physics, Thákurova 7, 166 29 Prague 6, Czech Republic, eva.mnahoncakova@fsv.cvut.cz

²CTU in Prague, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech Republic

The results of experimental determination of thermal and hygric parameters of high performance concrete measured at laboratory temperature after thermal load are presented in the paper.

Keywords: High performance concrete; Thermal properties; Hygric properties

Proceedings 157-160

EFFECT OF ADDITIVES ON HEAT GENERATION AT GYPSUM HYDRATION

Vratislav Tydlitát, Pavel Tesárek, Robert Černý.

Czech Technical University, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech Republic, tydlitat@fsv.cvut.cz

The process of hydration heat generation at solidification and hardening of FGD gypsum without and with additives is monitored at room temperature using an isothermal calorimeter based on the measurement of heat flow. The results obtained at the measurements of reaction heat generation are analyzed and data for various gypsum modifications compared with the reference material.

Keywords: Modified calcined gypsum; Heat flow calorimeter

Proceedings 161-164

inverse modeling of coupled moisture and salt transport

Lukáš Fiala^a, Zbyšek Pavlík^a, Milena Jiřičková^a, Pavla Rovnaníková^b, Robert Černý^a

^AČVUT v Praze, Stavební fakulta, Katedra stavební mechaniky, Thákurova 7, 16629 Praha 6, Czech Republic, cernyr@fsv.cvut.cz

^BVUT v Brně, Stavební fakulta, Ústav chemie, Žižkova 17, 60200 Brno, Czech Republic

Inverse analysis of coupled moisture and salt transport is presented in the paper. The diffusion-advection mode of salt solution transport is assumed. The moisture and sodium chloride concentration profiles measured in cement mortar together with the chloride binding isotherm are used in the inverse analysis.

Keywords: Moisture profiles; Salt concentration profiles; Inverse analysis

Proceedings 165-168

CHLORIDE AND NITRATE BINDING ISOTHERMS OF SELECTED BUILDING MATERIALS

Milena Jiřičková, Dita Stoklasová, Robert Černý

CTU in Prague, Fakulty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 16629 Prague 6, Czech Republic, jiricko@fsv.cvut.cz

In this paper, chloride and nitrate binding isotherms are determined for ceramic brick, calcium silicate, cement paste and sandstone. The applied experimental method is based on the adsorption method by Tang and Nilsson. The measured data will be used as input parameters of mathematical models of coupled moisture and salt transport.

Keywords: Ion binding isotherms; Building materials

Proceedings 169-172

MOISTURE AND SALT TRANSPORT PARAMETERS OF SANDSTONE FROM MŠENÉ QUARRY

Zbyšek Pavlík, , Petr Michálek, Milena Jiřičková, Dita Stoklasová, Robert Černý

CTU in Prague, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 16629 Prague 6, Czech Republic, petr.michalek@fsv.cvut.cz

Measurement of basic moisture and salt transport parameters of sandstone from Mšené quarry is described in the paper. The measured data giving basic information on the properties of this material will serve to an analysis of the mechanism of moisture and salt transport and to the investigation of degradation due to the presence of salt solutions.

Keywords: Moisture and salt transport parameters; Sandstone

Proceedings 173-176

HYGRIC AND THERMAL PROPERTIES OF A MATERIAL ON THE ALKALI ACTIVATED SLAG BASIS AFTER HIGH TEMPERATURE EXPOSURE

Lucie Zuda¹, Jan Toman², Robert Černý¹,Pavla Rovnaníková³

¹CTU in Prague, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech republic, cernyr@fsv.cvut.cz

²CTU in Prague, Faculty of Civil Engineering, Department of Physics, Thákurova 7, 166 29 Prague 6, Czech Republic

³VUT v Brně, Stavební Fakulta, Ústav Chemie, Žižkova 17, 662 37 Brno, Czech Republic

Basic thermal and hygric properties of a material on the alkali activated slag basis exposed previously to high temperatures are measured in room temperature conditions. The measured parameters are compared with the results of reference measurement performed on the same material without any thermal loading.

Keywords: Alkali activated slag; Hygric properties; Thermal properties

Proceedings 177-180

INFLUENCE OF HYDROPHILIC ADMIXTURES ON MOISTURE PROPERTIES OF MINERAL WOOL

Zbyšek Pavlík, , Petr Michálek, Milena Jiřičková, Vratislav Tydlitát, Robert Černý

CTU in Prague, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech Republic, tydlitat@fsv.cvut.cz

The influence of hydrophilic additives on moisture properties of materials on mineral wool basis is studied in the paper. Material parameters describing the liquid moisture and water vapour transport are determined. Basic material parameters such as bulk density, matrix density and porosity are also given. For the sake of assessment of the influence of hydrophilic additives, the parameters of a mineral wool material without any admixture are analyzed as well.

Keywords: Hydrophilic mineral wool; Moisture transport parameters

Proceedings 181-184

ThE Evaluation of anticorrosive thermal resistance pigmented films

David Veselý, Petr Kalenda, Andrea Kalendová

Institute of polymer materials, University of Pardubice, Čs. Legií sq. 565, 532 10 Pardubice, Czech republic, david.vesely@upce.cz

The anticorrosion protection of metal using organic coatings destined for the aplications at temperatures in a range of 200-500 ^oC is a specific problem both from the binder base and appropriate anticorrosive pigment points of view. A prospective and efficient solution is provided by using anticorrosive spinel-type pigments. The stability of spinel-like compounds consists in the stabilities of their compositions and structures, which manifest themselves in the stability of physicochemical structures thereof, so as in constancies of color and application properties.

Keywords: Coatings; Spinel; Pigment; Corrosion protection; Silicone resin

Proceedings 185-188

Reaction to fire tests for building products

Lenka Horčičková, Mirko Louma

PAVUS, a.s., Authorized body AO 216, CZ-391 81, Veselí nad Lužnicí, louma@pavus.cz

The classification of reaction to fire of building products is based on the European classification system defined in ČSN EN 13501-1. This classification is determined by the specified test procedures. One of the most widely used methods is a test described in ČSN EN ISO 1716 Reaction to fire tests for building products – Determination of the heat of combustion. The method can be applied to the homogenous products, substantial and non – substantial components of the non – homogenous products.

Keywords: Heat of combustion; Building product; Reaction to fire; Classification

Proceedings 191-194

THE APARATUS FOR THERMOMECHANICAL ANALYSIS OF CERAMICS

Anton Trník, Libor Vozár, Igor Štubňa

Physics Dpt., Constantine the Philosopher University, A Hlinku 1, 949 74 Nitra, Slovakia, atrnik@ukf.sk

It is described an apparatus for modulated force thermomechanical analysis (mf-TMA) of ceramics in temperature range 20 – 1200 °C. Mf-TMA is based on measurement of the resonant frequency of flexural vibration of the sample. The vibration is excited by electrodynamical driver, which is fed with sweep generator ETC M321 in the range of f_rez ± 100 Hz. A cantilever pickup with sensitive element made from PZT ceramics takes the amplitude of the vibration. This signal is led into preamplifier and then in the input of measuring card Advantech PCL-818 HG. The frequency range of the driver and pickup is 0 – 5000 Hz. The sound velocity can be calculated from measured resonant frequency and dimensions of the sample. For determination of the Young´s modulus, the mass of the sample has to be known. Relative error of the determination of the sound velocity is 1.25 % and that of the Young´s modulus is 2.5 %. A temperature is measured by Pt-PtRh10 thermocouple, a thermo-emf is magnified by preamplifier Tesla Z30. A PI controller feeds the 2.5 kW furnace to reach required temperature course.

Keywords: Mf-TMA; Flexural vibration; Mechanical resonant method

Proceedings 195-198

GLASS TRANSITION OF 15Na₂O . xMgO . (10–x)CaO . 75SiO₂ GLASSES

Štefan Valovič^A, Mária Chromčíková^B, Marek Liška^B

^A) Katedra fyziky, Univerzita Konštantína Filozofa, Trieda A. Hlinku 1, Nitra, SK-949 74, e‑mail: svalovic@ukf.sk

^B) Centrum kompetencie skla Vitrum Laugaricio, spoločné pracovisko Ústavu anorganickej chémie SAV, Trenčianskej univerzity Alexandra Dubčeka a RONA, a.s., Študentská 2, Trenčín, SK-911 50

Heat capacities of 15Na₂O.xMgO.(10–x)CaO.75SiO₂ glasses were measured in temperature range from 400°C to 650°C with various rates of heating. Glass transition temperature and the step of heat capacity were calculated with respect to the DIN, ASTM, Mettler Toledo STAR^e and Richardson midpoint. The glass transition temperature values were compared with those obtained by thermodilatometry. In agreement with the theory a rising of the glass transition temperature with increasing heating rate was observed. Local minimum of the glass transition temperature (and maximum of delta c_p) was observed at x = 6 mol. %.

Keywords: Glass; Glass-transition; Heat capacity; DSC

Proceedings 199-202

CRYSTALLIZATION KINETICS IN AMORPHOUS MATERIALS MEASURED BY DSC

Jana Shánělová,^A Daniel Švadlák,^A Petr Němec^B

Department of physical chemistry^A and Department of general and inorganic chemistry^B, Faculty of Chemical Technology, University Pardubice, Nám. Čs. Legií 565, Pardubice 532 10, Czech Republic, jana.shanelova@upce.cz

The crystallization in (Ge₃₀Ga₅Se₆₅)_99,5(Pr₂Se₃)_0,5 were studied by DSC. It was found that crystallization is very quick and DTA method is not applicable to follow this process. From DSC data the crystallization enthalpy -58,1 J/g, activation energy 219 kJ/mol, pre-exponencial factor A = 1,175.10¹⁵ s^-1 and rate constant at 500°C 1,878 s^-1 were determined. The empirical model SB (0,67, 1,28) was found to describe this process, which is effected by surface crystallization, nucleation on doped Pr³⁺ ionts and diffusion process on the interface crystal‑glass. The nucleation growth model JMA is not acceptable in this case.

Keyword: DSC; Crystallization; Chalcogenide; Glasses; Ge-Ga-Se

Proceedings 203-206

KINETICS OF CRYSTALLIZATION OF THE UNDERCOOLED MELTS

Jana Holubová^A, Zdeněk Černošek^A, Eva Černošková^B, M. Liška^C

^ADepartment of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, nám. Legií 565, Pardubice, Czech Republic,jana.holubova@upce.cz

^BJoint Laboratory of Solid State Chemistry of Institute of Macromolecular Chemisty of Czech Academy of Sciences and University Pardubice, Studentská 84, Pardubice, Czech Republic,

^CVitrum Laugaricio (VILA) - Joint Glass Center of Institute of Inorganic Chemistry SAS, Alexander Dubček University of Trenčín and RONA Lednické Rovne, Študentská 2, Trenčín, Slovak Republic.

The applicability of the kinetic analysis of data obtained by non-isothermal differential scanning calorimetry is discussed. It was found that the correct determination of non-isothermal crystallization parameters depends on the knowledge of temperature dependence of the kinetic exponent n. Since the temperature dependence of n cannot be determined on the basis of non-isothermal DSC experiments, conclusions of kinetic analysis of non-isothermal data must be drawn with appropriate caution.

Keywords: Crystallization; Undercooled melts; JMA model; Non-isothermal DSC

Proceedings 207-210

STUDY OF CRYSTALLIZATION AND MELTING BY STEPSCAN DSC

Zdeněk Černošek^A, Jana Holubová^A, Eva Černošková^B, Marek Liška^C

^ADepartment of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, nám. Legií 565, Pardubice, Czech Republic, zdenek.cernosek@upce.cz

^BJoint Laboratory of Solid State Chemistry of Institute of Macromolecular Chemisty of Czech Academy of Sciences and University Pardubice, Studentská 84, Pardubice, Czech Republic.

^CVitrum Laugaricio (VILA) - Joint Glass Center of Institute of Inorganic Chemistry SAS, Alexander Dubček University of Trenčín and RONA Lednické Rovne, Študentská 2, Trenčín, Slovak Republic.

Crystallization and melting of model glass-forming melts of Se, As₂Se₃ and As₂S₃ were studied by means of StepScan DSC. Enthalpic changes of both phase transformations could be divided into two parts: one of them is reversible and temperature dependent and the second one, that is irreversible and temperature independent. The later, except for sign, is the same for crystallization and melting. Comparing temperature dependencies of reversible parts of both undercooled melt and crystal melting enthalpies showed that at some temperature T_o both reversible enthalpies are equal and at lower temperatures enthalpy of undercooled melt (and glass) is even lower than the reversible one of crystalline phase. From it follows and it is also experimentally verified that undercooled melt at temperature under T_o cannot undergo crystallization. T_o means the higher temperature of undercooled melt stability. Its technological importance could be indispensable.

Keywords: Standard DSC; StepScan DSC; Crystallization; Melting; Enthalpy

THERMAL AND HYGRIC PROPERTIES OF MODIFIED CALCINED GYPSUM

Pavel Tesárek, Robert Černý

CTU in Prague, Faculty of Civil Engineering, Department of Structural Mechanics, Thákurova 7, 166 29 Prague 6, Czech Republic, cernyr@fsv.cvut.cz

Measurements of thermal and hygric properties of calcined gypsum modified by application of hydrophobized admixtures supposed to increase its hygric properties are presented in the paper. The measured parameters are compared with the results achieved with reference calcined gypsum without any modifications.

Keywords: Modified calcined gypsum; Thermal properties; Hygric properties