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5631 articles

B3324 – Structural, energetic and reactivity properties of phenoxazine and phenothiazine

A combined experimental and computational study was developed with the aim of evaluate and understand the structural, energetic and reactivity properties of phenoxazine and phenothiazine. Experimentally, differential scanning calorimetry, static and rotating bomb combustion calorimetries, Knudsen effusion and Calvet microcalorimetry were employed to determine, respectively, the standard (p° = 0.1 MPa) molar enthalpies of fusion, , at the temperature of fusion, the standard molar enthalpies of formation, in the crystalline phase, , at T = 298.15 K, the temperature-vapor pressures dependences, and the standard molar enthalpies of sublimation, , at T = 298.15 K. These data allowed the derivation the experimental standard molar enthalpies of formation, in the gaseous phase, , of phenoxazine, (100.8 ± 4.3) kJ · mol?1, and of phenothiazine, (273.5 ± 4.7) kJ · mol?1. Computationally, the composite G3(MP2)//B3LYP approach was used to optimize the structures of these two compounds and to estimate their values, which are found to be in very good agreement with the experimental ones. Calculations were also performed for additional analyses of their natural bond orbitals (NBO) and to obtain other gas-phase thermodynamic properties, namely N–H bond dissociation enthalpies, gas-phase acidities and basicities and proton affinities.
Vera L.S. Freitas, José R.B. Gomes, Maria D.M.C. Ribeiro da Silva, J. Chem. Thermodynamics (2013)

B3313 – Fundamental environmental reactivity testing and analysis of the hydrogen storage material 2LiBH4$MgH2

While the storage of hydrogen for portable and stationary applications is regarded as critical in bringing PEM fuel cells to commercial acceptance, little is known of the environmental exposure risks posed in utilizing condensed phase chemical storage options as in complex hydrides. It is thus important to understand the effect of environmental exposure of metal hydrides in the case of accident scenarios. Simulated tests were performed following the United Nations standards to test for flammability and water reactivity in air for a destabilized lithium borohydride and magnesium hydride system in a 2 to 1 molar ratio respectively. It was determined that the mixture acted similarly to the parent, lithium borohydride, but at slower rate of reaction seen in magnesium hydride. To quantify environmental exposure kinetics, isothermal calorimetry was utilized to measure the enthalpy of reaction as a function of exposure time to dry and humid air, and liquid water. The reaction with liquid water was found to increase the heat flow significantly during exposure compared to exposure in dry or humid air environments. Calorimetric results showed the maximum normalized heat flow of the fully charged material was 6 mW/mg under liquid phase hydrolysis; and 14 mW/mg for the fully discharged material also occurring under liquid phase hydrolysis conditions.
Charles W. James Jr., Kyle S. Brinkman, Joshua R. Gray, Jose A. Cortes-Concepcion, Donald L. Anton, International Journal of Hydrogen Energy (2013) 1-11

B3323 – Calorimetric study of 2′-methylacetophenone and 4′-methylacetophenone

Values of the condensed phase standard (p = 0.1 MPa) molar enthalpy of formation for 2?- and 4?-methylacetophenones were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The values of the standard molar enthalpy of vaporization, at T = 298.15 K, were measured by Calvet microcalorimetry. Combining these two values, the following enthalpies of formation in the gas phase, at T = 298.15 K, were then derived: 2?-methylacetophenone, –(115.7 ± 2.4) kJ · mol?1, and 4?-methylacetophenone, –(122.6 ± 2.4) kJ · mol?1. Substituent effects are discussed in terms of stability and compared with other similar compounds. The value of the standard molar enthalpy of formation for 3?-methylacetophenone was estimated from isomerization schemes.
Luísa M.P.F. Amaral, Manuel A.V. Ribeiro da Silva, J. Chem. Thermodynamics 57 (2013) 301–305

B3322 – Experimental thermochemical study of 2-chloroacetophenone and 2,4’-dichloroacetophenone

The standard (p? = 0.1 MPa) molar enthalpies of formation of 2-chloroacetophenone and 2,4’-dichloroacetophenone, in the gaseous phase, at T = 298.15 K, were derived from the combination of the values of the standard molar enthalpies of formation in the crystalline phase, at T = 298.15 K, and the standard molar enthalpies of sublimation of each compound, at the same temperature. The standard molar enthalpies of formation, in the crystalline phase, were derived from the corresponding standard massic energies of combustion, in oxygen, at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The standard molar enthalpy of sublimation of 2-chloroacetophenone was measured by Calvet microcalorimetry whereas the standard molar enthalpy of sublimation for 2,4’-dichloroacetophenone was calculated by application of the Clausius–Clapeyron equation to the vapor pressures at several temperatures measured by the Knudsen effusion technique
Luísa M.P.F. Amaral, Manuel A.V. Ribeiro da Silva, J. Chem. Thermodynamics (2013)

B3321 – Excess molar enthalpies for binary mixtures of 1,2-dichloroethane with ethers at 298.15 K and atmospheric pressure

Excess molar enthalpies, HE, for the binary mixtures of 1,2-dichloroethane (1,2-DCE) with diethyl ether (DEE), methyl 1,1-dimethylethyl ether (MTBE), diisopropyl ether (DIPE), 1,3-dioxolane (1,3-DIOXO), 1,4-dioxane (1,4-DIOXA), tetrahydropyran (THP), ethylene glycol dimethyl ether (EGDME), diethylene glycol dimethyl ether (DEGDME), and diethylene glycol diethyl ether (DEGDEE), have been measured at 298.15 K and atmospheric pressure, using a Setaram Tian-Calvet C80 microcalorimeter. All the binary systems investigated are characterized by exothermic mixing over the entire composition range, except for 1,2-DCE + DIPE which presents a S-shape HE behavior. The experimental HE data have been fitted to the Redlich–Kister polynomial equation.
Fouzia Amireche-Ziar, Dominique Richon, Farid Brahim Belaribi, Fluid Phase Equilibria 337 (2013) 255– 258

B3320 – Correlation and prediction of the phase behavior and thermal properties of binary and ternary systems of 2,2′ -oxybis[propane] + benzene, toluene, cyclohexane or n-heptane

The experimental excess molar enthalpies data of liquid binary and ternary mixtures of DIPE with benzene, toluene, cyclohexane and n-heptane have been measured at 303.15 K and constant pressure using a Calvet type microcalorimeter, C80 (Setaram, France). A Redlich–Kister type equation was used to correlate experimental values. The theoretical results obtained by the DISQUAC model are significantly closer to the experimental values
Saéda Didaoui, Ahmed Ait-Kaci, Thermochimica Acta 567 (2013) 46– 50

B3330 – Effect of whey protein agglomeration on spray dried microcapsules containing Saccharomyces boulardii

This work investigates the effect of whey protein agglomeration on the survivability of Saccharomyces boulardii within spray dried microcapsules. It attempts to go beyond phenomenological observations by establishing a relationship between physicochemical characteristics of the polymeric matrix and its effect on probiotic endurance upon spray drying. It is well known that this type of thermal shock has lethal consequences on the yeast cells. To avoid such undesirable outcome, we take advantage of the early agglomeration phenomenon observed for whey protein by adjusting the pH value of preparations close to isoelectric point (pH 4-5). During the subsequent process of spray drying, development of whey protein agglomerates induces formation of an early crust, and the protein in this molten globular state creates a cohesive network encapsulating the yeast cells. It appears that the early crust formation at a given sample pH and temperature regime during spray drying benefits the survivability of S. boulardii within microcapsules.
Diep Duongthingoc, Paul George, Lita Katopo, Elizabeth Gorczyca, Stefan Kasapis, Food Chemistry 141 (2013) 1782–1788

B3329 – Topological investigations of thermodynamic properties of ionic liquid mixtures: Excess molar volumes and excess isentropic compressibilities

The densities, ?, speeds of sound, u, and heat capacities, Cp of pure 1-ethyl-3-methylimidazolium tetrafluoroborate, aniline, N-methylaniline, 2-methylaniline and 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + 2-methylaniline (j) + aniline or N-methylaniline (k) ternary and their 2-methylaniline (j) + aniline or N-methylaniline (k) binary mixtures have been measured as a function of composition at 293.15, 298.15, 303.15, 308.15 K and atmospheric pressure. The observed densities and speeds of sound data have been employed to determine excess molar volumes, VE and excess isentropic compressibilities, ?SE of the investigated mixtures. The observed thermodynamic properties of the binary as well as ternary mixtures have been calculated by utilizing the topology of the constituents of mixtures (graph theory). It has been observed that graph theory successfully describes well the VE and ?SE data of the studied binary as well as ternary ionic liquid mixtures.
V.K. Sharma, S. Solanki, S. Bhagour, D. Sharma, Journal of Molecular Liquids 188 (2013) 258–271

B3328 – Topological investigations of excess heat capacities of binary liquid mixtures containing lactams and cycloalkanone

The excess heat capacities, CPE, of binary 1-Methylpyrrolidin-2-one or pyrrolidin-2-one (i) + cyclopentanone or cyclohexanone or cycloheptanone or cyclohexane (j) mixtures were obtained over the entire mole fraction range using micro-differential scanning calorimeter (Model — ?DSC 7 Evo) in the temperature range from 293.15 to 308.15 K at atmospheric pressure. The observed data have been fitted to Redlich–Kister equation to calculate adjustable parameters and standard deviations. The Moelwyn–Huggins concept of interactions between the components of mixture has been utilized using the topology of the constituent molecules (Graph theory) to determine excess heat capacities, CPE of the studied mixtures. The results obtained indicate that CPE values calculated by Graph theory are in agreement with experimental values
V.K. Sharma, J. Kataria, Journal of Molecular Liquids 188 (2013) 210–221

B3327 – Energetics of 2- and 3-coumaranone isomers: A combined calorimetric and computational study

Condensed phase standard (p° = 0.1 MPa) molar enthalpies of formation for 2-coumaranone and 3-coumaranone were derived from the standard molar enthalpies of combustion, in oxygen, at T = 298.15 K, measured by mini-bomb combustion calorimetry. Standard molar enthalpies of sublimation of both isomers were determined by Calvet microcalorimetry. These results were combined to derive the standard molar enthalpies of formation of the compounds, in gas phase, at T = 298.15 K. Additionally, accurate quantum chemical calculations have been performed using DFT methods and high level composite ab initio calculations. Theoretical estimates of the enthalpies of formation of the compounds are in good agreement with the experimental values thus supporting the predictions of the same parameters for isobenzofuranone, an isomer which has not been experimentally studied. The relative stability of these isomers has been evaluated by experimental and computational results. The importance of some stabilizing electronic intramolecular interactions has been studied and quantitatively evaluated through Natural Bonding Orbital (NBO) analysis of the wave functions and the nucleus independent chemical shift (NICS) of the studied systems have been calculated in order to study and establish the effect of electronic delocalization upon the relative stability of the isomers.
Clara C.S. Sousa, M. Agostinha R. Matos, Luís M.N.B.F. Santos, Victor M.F. Morais, J. Chem. Thermodynamics 67 (2013) 210–216

B3326 – Energetics and molecular structure of alkyl 1-methylpyrrolecarboxylates (alkyl = methyl or ethyl)

Calorimetric techniques, namely static bomb calorimetry and high temperature Calvet microcalorimetry were used to derive, respectively, the standard (po = 0.1 MPa) molar enthalpy of formation, in the liquid phase, , and the standard molar enthalpy of vaporization, at T = 298.15 K, , of the methyl 1-methyl-2-pyrrolecarboxylate (M1M2PC). These experiments allowed the determination of its standard (po = 0.1 MPa) molar enthalpy of formation, in the gaseous phase, = ?(270.3 ± 2.2) kJ · mol?1, at T = 298.15 K. Additionally, the standard molar enthalpy of formation of M1M2PC was estimated by computations based on standard ab initio molecular calculations at the G3(MP2)//B3LYP level. The estimated values are in very good agreement with experimental one, giving us support to estimate the gas-phase enthalpies of formation of the methyl 1-methyl-3-pyrrolecarboxylate (M1M3PC), ethyl 1-methyl-2-pyrrolecarboxylate (E1M2PC) and ethyl 1-methyl-3-pyrrolecarboxylate (E1M3PC), that were not studied experimentally. The molecular structures of the four molecules were established and the structural parameters were determined at the B3LYP/6-31G(d) level of theory. Furthermore, all the results were interpreted in terms of enthalpic increments.
Ana Filipa L.O.M. Santos, Manuel A.V. Ribeiro da Silva, J. Chem. Thermodynamics 67 (2013) 190–196

B3325 – Energetics and stability of azulene: From experimental thermochemistry to high-level quantum chemical calculations

The standard (p0 = 0.1 MPa) molar enthalpy of formation for crystalline azulene was derived from the standard molar enthalpy of combustion, in oxygen, at T = 298.15 K, measured in a mini-bomb combustion calorimeter (aneroid isoperibol calorimeter) and the standard molar enthalpy of sublimation, at T = 298.15 K, measured by Calvet microcalorimetry. From these experiments, the standard molar enthalpy of formation of azulene in the gaseous phase at T = 298.15 K was calculated. In addition, very accurate quantum chemical calculations at the G3 and G4 composite levels of calculation were conducted in order to corroborate our experimental findings and further clarify and establish the definitive standard enthalpy of formation of this interesting non-benzenoid hydrocarbon.
Clara C.S. Sousa, M. Agostinha R. Matos, Victor M.F. Morais, J. Chem. Thermodynamics (2013)

B3331 – Heat capacities and the two-point scaling analysis of short-chain surfactant solutions

The apparent molar heat capacities of two short-chain surfactants (C6TAB and C8TAB) aqueous solutions were determined at four temperatures. For the hexyltrimethylammonium bromide no structural transition was observed. For the octyltrimethylammonium bromide a maximum of the apparent molar heat capacity was observed, which corresponds to the monomer to micelle transition. The two-point scaling theory, that describes the thermodynamics of the system, which can appear in two phases in the vicinity of critical point, was applied to analyse this system. The critical molalities and critical indices were obtained. Comparison of these values with those previously reported for other similar systems allowed to relate them with structure changes in the solution.
M. Wasiaka, W. Kunz, H. Piekarski, Fluid Phase Equilibria 358 (2013) 78– 82

B3341 – Saccharide effect on the LCST property of a polyether: Influence of structure and length

Saccharides and especially monosaccharides are well-known to affect the thermal transition of the LCST polymer solution. The studied LCST system is an aqueous polyetheramine solution under unprotected form. The role of saccharide has clearly been highlighted through thermal measurements (absorbance and ?DSC) and structural techniques (NMR). Moreover, the impact of the structure and the number of the saccharides unit have been disclosed on the cloud point temperature. The phase transition became lowered upon sugar addition.
Sabrina Belbekhouche, Virginie Dulong, Luc Picton, Didier Le Cerf, Colloids and Surfaces A: Physicochem. Eng. Aspects 428 (2013) 25– 31

B3340 – Biophysical changes induced by xenon on phospholipid bilayers

Structural and dynamic changes in cell membrane properties induced by xenon, a volatile anesthetic molecule, may affect the function of membrane-mediated proteins, providing a hypothesis for the mechanism of general anesthetic action. Here, we use molecular dynamics simulation and differential scanning calorimetry to examine the biophysical and thermodynamic effects of xenon on model lipid membranes. Our results indicate that xenon atoms preferentially localize in the hydrophobic core of the lipid bilayer, inducing substantial increases in the area per lipid and bilayer thickness. Xenon depresses the membrane gel-liquid crystalline phase transition temperature, increasing membrane fluidity and lipid head group spacing, while inducing net local ordering effects in a small region of the lipid carbon tails and modulating the bilayer lateral pressure profile. Our results are consistent with a role for nonspecific, lipid bilayer-mediated mechanisms in producing xenon's general anesthetic action.
Ryan D. Booker, Amadeu K. Sum, Biochimica et Biophysica Acta 1828 (2013) 1347–1356

B3339 – Relationship between meat toughness and properties of connective tissue from cows and young bulls heat treated at low temperatures for prolonged times

The aim of the current study was to elucidate whether cows and young bulls require different combinations of heating temperature and heating time to reduce toughness of the meat. The combined effect of heating temperature and time on toughness of semitendinosus muscle from the two categories of beef was investigated and the relationship to properties of connective tissue was examined. Measurements of toughness, collagen solubility, cathepsin activity and protein denaturation of beef semitendinosus heated at temperatures between 53°C and 63°C for up to 19 1/2 h were conducted. The results revealed that slightly higher temperatures and prolonged heating times were required to reduce toughness of semitendinosus from cows to the same level as in young bulls. Reduced toughness of semitendinosus as a result of low temperature for prolonged time is suggested to result from weakening of the connective tissue, caused partly by denaturation or conformational changes of the proteins and/or by solubilization of collagen.
Line Christensen, Per Ertbjerg, Hanne Løje, Jens Risbo, Frans W.J. van den Berg, Mette Christensen, Meat Science 93 (2013) 787–795

B3338 – Thermosensitive hybrid hydrogels with silica nanoparticle-cross-linked polymer networks

A simple methodology for the preparation of thermosensitive organic-inorganic hybrid hydrogels using silica nanoparticle-mediated polymer networks is described. A thermosensitive copolymer poly[N-isopropylacrylamide-co-(3-methacryloxypropyltrimethoxysilane)], (pNS), with reactive side chains (Si-O-CH3) was first synthesized by free radical polymerization using N-isopropylacrylamide (NIPAAm) and 3-methacryloxypropyltrimethoxysilane (MAPTS). Then, simple mixing of the aqueous solution of this copolymer with silica nanoparticle (SiP) suspensions at room temperature led to the formation of thermosensitive hybrid hydrogels cross-linked with silica nanoparticles (SiP) which did not require any other processing like washing for the removal of unreacted monomers and initiators. The effects of SiP content on gelation abilities, temperature-responsive behaviors, swelling and deswelling kinetics, and mechanical properties of the hydrogels were investigated. The results showed that transparent hybrid hydrogels with adjustable network structures were obtained within a few minutes to a couple of hours depending on the concentration of the copolymers and the silica nanoparticles. The hybrid hydrogels exhibited a lower critical solution temperature (LCST) of around 33 °C with no significant deviation from conventional poly(N-isopropylacrylamide) hydrogels; the LCST was not significantly affected by the concentration of silica nanoparticles (which in these systems serve as the cross-linkers). In addition, the hydrogels showed significantly large equilibrium swelling ratios, improved mechanical strength, and suitable deswelling behavior, which can easily be tuned by varying the composition of the hybrid hydrogels.
Md. Ashraful Alam, Makoto Takafuji, Hirotaka Ihara, Journal of Colloid and Interface Science 405 (2013) 109–117

B3348 – Hybrid organic–inorganic materials as coatings for protecting wood

A new coating based on organic–inorganic materials was prepared using concurrent sol–gel and polymerization techniques, and applied to wood using a dip coating method. Vinyl-functionalized zirconium oxoclusters were co-polymerized with vinyltrimethoxysilane on wood. The coating process was examined, also assessing the specific weight of hybrid polymer left on the wood after one or two coating steps. The efficacy of the process in consolidating and protecting the wood was investigated using high-temperature differential scanning calorimetry (DSC), environmental scanning electron microscopy (ESEM), infrared spectroscopy and solid state NMR spectroscopy. The coating did not affect the morphology and appearance of the wood. However, it did modify its behavior on exposure to fire and preliminary accelerated biological tests with the brown rot fungus Coniophora puteana showing an improved resistance to the fungal attack.
F. Girardi, E. Cappelletto, J. Sandak, G. Bochicchio, B. Tessadri, S. Palanti, E. Feci, R. Di Maggio, Progress in Organic Coatings 77 (2014) 449–457

B3337 – Poly(N-isopropylacrylamide)-block-poly(vinyl pyrrolidone) block copolymer networks: Synthesis and rapid thermoresponse of hydrogels

In this work, we reported the synthesis of poly(N-isopropyl acrylamide)-block- poly(N-vinylpyrrolidone)-block-poly(N-isopropylacrylamide) triblock copolymer (PNIPAAm-b-PVPy-b-PNIPAAm) via reversible addition-fragmentation chain transfer polymerization/macromolecular design via the interchange of xanthate (RAFT/MADIX) process. This approach was further employed to prepare the PNIPAAm-b-PVPy block copolymer networks with N,N?-methylenebisacrylamide as the crosslinker. The results of small angle X-ray scattering (SAXS) indicate that the PNIPAAm-b-PVPy block copolymer networks were microphase-separated, in which PVPy was dispersed into PNIPAAm matrix as the microdomains. The architecture of block copolymer networks allows investigating the effect of the blocked permanently hydrophobic chains (viz. PVPy) on the deswelling and reswelling behavior of the PNIPAAm hydrogels. It was found that the diffusion of water molecules in PNIPAAm-b-PVPy block copolymer networks was in a non-Fickian and accelerating manner. The swelling ratios of the PNIPAAm-b-PVPy hydrogels were significantly higher than that of control PNIPAAm hydrogel. Compared to control PNIPAAm hydrogel, the PNIPAAm-b-PVPy hydrogels displayed an accelerated response to the external temperature changes in terms of deswelling and reswelling tests. The accelerated thermoresponsive properties is ascribed to the presence of the PVPy blocks in the PNIPAAm-b-PVPy block copolymer networks, which could act as the hydrophilic tunnels to facilitate the diffusion of water molecules in the PNIPAAm networks
Houluo Cong, Lei Li, Sixun Zheng, Polymer 54 (2013) 1370-1380

B3347 – Thermodynamic assessment and experimental study of Mg–Gd alloys

The solid solubility of Gd in (Mg) is studied experimentally using microstructure, chemical and EDX analysis on permanent mould chill cast samples which were annealed for 1–14 days at 300–550 °C. Based on those key data and all the critically assessed experimental phase equilibrium and thermodynamic data of the Mg–Gd system two Calphad-type thermodynamic descriptions are developed. This provides calculated phase diagrams, and an inherent inconsistency between the vapor pressure data and the Mg-rich phase diagram is indicated. A previous misperception of “experimental” enthalpy of formation data of binary GdxMgy intermetallic compounds is also revealed. The assumption of systematic trends in these key thermodynamic data for the series of rare earth elements R = (La, Ce, Pr, Nd, Sm, Gd) is scrutinized.
M. Hampl, C. Blawert, M.R. Silva Campos, N. Hort, Q. Peng, K.U. Kainer, R. Schmid-Fetzer, Journal of Alloys and Compounds 581 (2013) 166–177

B3336 – Structural studies on matrices of deacylated gellan with polydextrose

The effect of varying concentrations of co-solute (polydextrose) on thermomechanical and physicochemical properties of deacylated gellan matrices is presented. Modulated differential scanning calorimetry, micro differential scanning calorimetry, small deformation dynamic oscillation in shear, Fourier transform infrared spectroscopy, wide angle X-ray diffraction and environmental scanning electron microscopy have been used to investigate the structural transformations in aqueous, low-solid and condensed systems. There was a rise in values of storage modulus as the level of co-solute was increased, followed by a significant decline at intermediate concentrations, with high modulus values being regained as more of the co-solute was incorporated. These results confirm the hypothesis of a structural transformation from a highly enthalpic aggregated assembly in the aqueous/low-solid environment to a lightly cross linked polysaccharide network in the high solids regime. Time-temperature superposition (TTS) phenomena observed for amorphous synthetic polymers have been utilised to generate master curves of viscoelasticity, which afforded rationalisation of results on the basis of the free volume theory.
Vinita Chaudhary, Darryl M. Small, Stefan Kasapis, Food Chemistry 137 (2013) 37–44

B3346 – Phase transformation studies in U–Nb–Zr alloy

Phase transformation diagrams provide fundamental informations for designing thermomechanical processes being a must regarding uranium alloys nuclear fuels. The work shows the evaluation of a kinetic transformation diagram for U–7.5Nb–2.5Zr (wt.%) based on both calorimetry experiments and dilatometry allied to X-ray diffraction analysis. Calorimetry measurements in scanning and drop modes can detect enthalpies of heating and transformation onset points from ambient up to select isotherms while the dilatometer is used to scan for sample volume changes related to phase transformations. The resulted kinetic diagram shows the gamma phase is stable for this alloy, guiding the rolling deformation process to temperature ranges where this phase remains for longer periods. Comparing to the literature results, the low temperature transformation (300–400 °C) is shifted to longer times accordingly to the disclosed TTT kinetic diagram. Therefore, two forming process windows can be proposed at 200 °C and 400 °C neighborhood where gamma-phase remains for enough time to accomplish total reduction.
Denise Adorno Lopes, Thomaz Augusto Guisard Restivo, Angelo Fernando Padilha, Nuclear Engineering and Design 265 (2013) 619– 624

B3335 – Effect of high pressure processing on rheological and structural properties of milk–gelatin mixtures

There is an increasing demand to tailor the functional properties of mixed biopolymer systems that find application in dairy food products. The effect of static high pressure processing (HPP), up to 600 MPa for 15 min at room temperature, on milk–gelatin mixtures with different solid concentrations (5%, 10%, 15% and 20% w/w milk solid and 0.6% w/w gelatin) was investigated. The viscosity remarkably increased in mixtures prepared with high milk solid concentration (15% and 20% w/w) following HPP at 300 MPa, whereas HPP at 600 MPa caused a decline in viscosity. This was due to ruptured aggregates and phase separation as confirmed by confocal laser scanning microscopy. Molecular bonding of the milk–gelatin mixtures due to HPP was shown by Fourier-transform infrared spectra, particularly within the regions of 1610–1690 and 1480–1575 cm?1, which reflect the vibrational bands of amide I and amide II, respectively.
Anastasia Fitria Devi, Li Hui Liu, Yacine Hemar, Roman Buckow, Stefan Kasapis, Food Chemistry 141 (2013) 1328–1334

B3345 – Thermodynamic assessment of the (LiF + UF3) and (NaF + UF3) systems

In this article new thermodynamic descriptions of the (LiF + UF3) and the (NaF + UF3) systems based on new calorimetric data are presented. The experimental investigations were carried out using differential scanning calorimetry (DSC) to obtain phase transition temperatures between (0 and 60) mol% of UF3. On the basis of these measurements a thermodynamic assessment of the (LixU1-x)F3-2x and (NaxU1-x)F3-2x liquid solutions, using the quasi-chemical model was achieved. UF3 undergoes a disproportionation at higher temperatures to UF4 and U metal which had a significant impact on the transition temperatures in the (LiF + UF3) system. For this reason the influence of the presence of up to 15 mol% of UF4 in this system was calculated and compared to the experimental results. The final thermodynamic description was corrected for the pure binary system.
M. Beilmann, O. Beneš, R.J.M. Konings, Th. Fanghänel, J. Chem. Thermodynamics 57 (2013) 22–31

B3334 – Rheology and synergy of ?-carrageenan/locust bean gum/konjac glucomannan gels

The rheology and melting of mixed polysaccharide gels containing konjac glucomannan (KGM), locust bean gum (LBG) and K-carrageenan (KC) were studied. Synergy-type peaks in the Young's modulus at optimal mixing ratios were found for both KC/LBG and KC/KGM binary gels at a fixed total polysaccharide content (1:5.5 for LBG:KC and 1:7 for KGM:KC). The Young's modulus peak for KC/KGM was higher than for KC/LBG gels. The same stoichiometric mixing ratios were found when either LBG or KGM was added to KC at a fixed KC concentration, where the Young's modulus increased up to additions at the stoichiometric ratio, but leveled off at higher LBG or KGM additions. Addition of KGM or LBG to the 2-component gels beyond the stoichiometric (optimal) mixing ratio at a fixed total polysaccharide content led to a decrease in the Young's modulus and an increase in the rupture strain and stress in extension, and both trends were stronger for KGM than for LBG. Differential scanning calorimetry of the gels revealed the development of a second melting peak for the KC/KGM gels that increased with KGM addition up to higher KGM contents than the stoichiometric ratio. For the KC/LBG gels, only a slight broadening and shift to a higher temperature were observed. When the three polysaccharides were mixed, the DSC endotherms reflected only the main features of the interaction between KC and KGM, and the same was true for the fracture in extension. The different trends led to higher Young's moduli at intermediate KC concentrations when a 1:1 addition of LBG: KGM was used than when either only KGM or LBG was added at a fixed total polysaccharide concentration. This suggests that no special interactions arise when the three polysaccharides are mixed and the binding mechanisms are simply a sum of the bindings observed for KC/KGM and KC/LBG two-component gels.
Tom Brenner, Zheng Wang, Piyada Achayuthakan, Tetsuya Nakajima, Katsuyoshi Nishinari, Carbohydrate Polymers 98 (2013) 754– 760

B3344 – Experimentation and Thermodynamic Representations of Binaries Containing Compounds of Low Boiling Points: Pentane and Alkyl Methanoates

This work presents experimental mixing properties, hE and vE, at several temperatures and the isobaric vapor–liquid equilibria (iso-p VLE) at 101.32 kPa for four binaries containing pentane and four alkyl (methyl to butyl) methanoates. Particular conditions are established to work with these solutions with highly volatile compounds, especially for the case of methyl methanoate + pentane system, for which a continuous feeding device is designed and constructed for measuring the densities. The mixing processes of the compounds chosen give rise to high values for the excess properties and also for the activity coefficients, since in addition to the known effects that arise in the binaries ester + alkane, in this case the associative effects caused by the HCOO– group, which diminish with increasing methanoate chain length are also relevant. The change in temperature produces slopes of opposite signs for the mixing properties, being p(?vE/?T)<0 and p(?hE/?T)>0. The systems comprised of methyl and ethyl methanoate with pentane present azeotropes with coordinates (xaz,Taz/K) situated at (0.558, 293.9) and (0.218, 306.5), respectively. The estimation of these coordinates and the iso-p VLE by the UNIFAC method are acceptable but do not give good predictions of the hE even less so for the LLE of the methyl methanoate + pentane system. For this binary, experimental data of all the properties are correlated with a mathematical procedure described using two models, one developed by us, and an extended form of the NRTL model. The latter does not represent the LLE data but shows the properties of isobaric equilibria, with acceptable results, while the proposed model, in addition to representing the binodal curve, gives a good representation of the vE and of these properties derived from excess Gibbs function.
L. Fernandez, J. Ortega,G. Sabater, F. Espiau, Fluid Phase Equilibria (2013)

B3333 – Thermotropic and structural effects of poly(malic acid) on fully hydrated multilamellar DPPC–water systems

The thermotropic and structural effects of low molecular weight poly(malic acid) (PMLA) on fully hydrated multilamellar dipalmitoylphosphatidylcholine (DPPC)-water systems were investigated using differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), and freeze-fracture transmission electron microscopy (FFTEM). Systems of 20wt% DPPC concentration and 1 and 5wt% PMLA to lipid ratios were studied. The PMLA derivatives changed the thermal behavior of DPPC significantly and caused a drastic loss in correlation between lamellae in the three characteristic thermotropic states (i.e., in the gel, rippled gel and liquid crystalline phases). In the presence of PBS or NaCl, the perturbation was more moderate. The structural behavior on the atomic level was revealed by FTIR spectroscopy. The molecular interactions between DPPC and PMLA were simulated via modeling its measured infrared spectra, and their peculiar spectral features were interpreted. Through this interpretation, the poly(malic acid) is inferred to attach to the headgroups of the phospholipids through hydrogen bonds between the free hydroxil groups of PMLA and the phosphodiester groups of DPPC.
Szilvia Berényi, Judith Mihály, Sándor Kristyán, Lívia Naszályi Nagy, Judit Telegdi, Attila Bóta, Biochimica et Biophysica Acta 1828 (2013) 661–669

B3343 – Development of thermoresponsive poly(propylene-g-N-isopropylacrylamide) non-woven 3D scaffold for smart cell culture using oxyfluorination-assisted graft polymerisation

Growing cells on 3D scaffolds is far superior to the conventional 2D monolayer culture method. In this study, a novel 3D thermoresponsive poly(propylene-g-N-isopropylacrylamide) (PP-g-PNIPAAm) non-woven fabric (gNWF) was developed for cell culture using oxyfluorination-assisted graft polymerisation (OAGP). New polar functional groups were detected on the oxyfluorinated NWF (oNWF), and PNIPAAm was confirmed in the gNWF by attentuated total-reflectance Fourier transform infrared (ATR-FTIR) and scanning X-ray photoelectron spectroscopy (S-XPS). Scanning electron microscopy (SEM) revealed a rough surface morphology and confinement of the PNIPAAm graft layer to the surface of the fibres in the gNWF. The OAGP method did not affect the crystalline phase of bulk PP, however, twin-melting thermal peaks were detected for the oNWF and gNWF indicating crystal defects. Contact angle studies showed that the surface of the gNWF exhibited a thermoresponsive behaviour. Hepatocyte cells attached onto gNWF disks in a bioreactor at 37 °C and remained viable for 10 days in culture. Upon cooling the cell culture media to 20 °C, cells were spontaneously released as 3D multi-cellular constructs without requiring destructive enzymes. The development of 3D thermoresponsive scaffolds capable of non-invasive 3D cell culture could provide a more reliable in vitro model for cells.
Avashnee S. Chetty, Viktoria Vargha, Arjun Maity, F. Sean Moolman, Claire Rossouw, Rajesh Anandjiwala, Lydia Boguslavsky, Dalu Mancama, Walter W. Focke, Colloids and Surfaces A: Physicochem. Eng. Aspects 419 (2013) 37– 45

B3332 – Association states of multisensitive smart polysaccharide–block-polyetheramine copolymers

The water soluble properties of different copolymers based on pullulan-block-polyetheramine have been deeply studied. The polyetheramine group (PEA) corresponding to a propylene oxyde/ethylene oxyde ratio (PO/EO) of 29/6, is condensed, via amine link, to pullulans with various chain lengths. Different polysaccharide/PEA (PS/PEA) ratio copolymers have been investigated through macroscopic (cloud point, enthalpy) and mesoscopic scale approaches (critical aggregation concentration (CAC), mean number average hydrodynamic diameter (Dh) or aggregation number (Nag)). These systems are both pH and/or thermo-sensitive. Finally, it seems that three states can describe such systems (i) isolated copolymers (unimers) below the CAC, (ii) water soluble aggregates above the CAC and whatever the PS/PEA ratio is due to hydrophobic interactions and (iii) non-soluble aggregates (above the critical temperature) due to dehydration of polyetheramine groups but only if PS/PEA ratio is low enough.
Sabrina Belbekhouche, Jacques Desbrières, Thierry Hamaide, Didier Le Cerf, Luc Picton, Carbohydrate Polymers 95 (2013) 41– 49

B3342 – Effect of microbial transglutaminase treatment on thermal stability and pH-solubility of heat-shocked whey protein isolate

Whey protein isolate (WPI) dispersions (5% protein, pH 7.0) were subjected to heat-shock at 70 °C for 1, 5 and 10 min. The heat-shocked WPI dispersions were treated with microbial transglutaminase (MTGase) enzyme, and thermal properties and pH-solubility of the treated proteins were investigated. Heat-shocking of WPI for 10 min at 70 °C increased the thermal denaturation temperature (Td) of ?-lactoglobulin in WPI by about 1.5 °C. MTGase treatment (30 h, 37 °C) of the heat-shocked WPI significantly increased the Td of ?-lactoglobulin by about 6.3–7.3 °C when compared with heat-shocked only WPI at pH 7.0. The Td increased by about 13–15 °C following pH adjustment to 2.5; however, the Td of heat-shocked WPI was not substantially different from heat-shocked and MTGase-treated WPI at pH 2.5. Both the heat-shocked and the heat-shocked-MTGase-treated WPI exhibited U-shaped pH-solubility profiles with minimum solubility at pH 4.0–5.0. However, the extent of precipitation of MTGase-treated WPI samples at pH 4.0–5.0 was much greater than all heat-shocked and native WPI samples. The study revealed that while MTGase cross-linking significantly enhanced the thermal stability of ?-lactoglobulin in heat-shocked WPI, it caused pronounced precipitation at pH 4.0–5.0 via decreasing the hydrophilic/hydrophobic ratio of the water-accessible protein surface.
Srinivasan Damodaran, Kingsley K. Agyare, Food Hydrocolloids 30 (2013) 12-18

B3351 – Study of order–disorder transitions in Fe–Ge alloys and related anelastic phenomena

Several methods were used to study the phase transitions and related anelastic mechanisms in some alloys of the Fe–Ge system. Obtained results show the appearance of the DTA and dilatometric effects at temperature 200–350 °C due to ordering process corresponding to the peak on internal friction curves (denoted as the P3 peak in this paper). The formation of ordered structure in Fe–Ge system at low Ge concentration is sensitive to the thermal history of the specimen. The formation of the ordered structure (with activation energy of ordering H ? 1.14 eV for a concentration of 12 at.% Ge) leads to the increase in the microhardness of studied alloys
Zehira Belamri, Djamel Hamana, Igor S. Golovin, Journal of Alloys and Compounds 554 (2013) 348–356

B3350 – Enthalpy of mixing of liquid Ag-Bi-Cu alloys at 1073K

The Ag–Bi–Cu system is among those ternary systems which have not been fully studied yet, in particular the thermodynamic description of the liquid phase is missing. Partial and integral enthalpies of mixing of liquid ternary Ag–Bi–Cu alloys were determined over a broad composition range along six sections: x(Ag)/x(Bi) = 0.25, 1, 4; x(Ag)/x(Cu) = 1.5; x(Bi)/x(Cu) = 1.86, 4. Measurements were carried out at 1073 K using two Calvet type microcalorimeters and drop calorimetric technique. It was found that integral enthalpies of mixing are small and endothermic, similarly to limiting binary alloys. The ternary data were fitted on the basis of an extended Redlich–Kister–Muggianu model for substitutional solutions. There are no significant additional ternary interactions.
P. Fima, H. Flandorfer, Thermochimica Acta (2013)

B3360 – The system Yb-Ru-O: High temperature studies on the oxides Yb2Ru2O7(s) and Yb3RuO7(s)

The standard molar Gibbs free energy of formation of Yb2Ru2O7(s) and Yb3RuO7(s) was determined using an oxide solid-state electrochemical cell wherein calcia-stabilized-zirconia (CSZ) was used as an electrolyte. The standard molar Gibbs free energy of formation of Yb2Ru2O7(s) and Yb3RuO7(s) from elements in their standard state was calculated by the least squares regression analysis of the data obtained in the present study and can be given respectively by: {?fG°(Yb2Ru2O7, s)/(kJ mol?1) ± 1.88} = ?2450.4 + 0.6025·(T/K) and {?fG°(Yb3RuO7, s)/(kJ mol?1) ± 2.36} = ?3109.6 + 0.6202·(T/K). Standard molar heat capacity C°p,m(T) of Yb2Ru2O7(s), was measured using a heat flux type differential scanning calorimeter (DSC) in the temperature range from 307 K to 845 K. The heat capacity of Yb2Ru2O7(s) was used along with the data obtained from the oxide electrochemical cell to calculate the standard enthalpy of formation of the compound Yb2Ru2O7(s), from elements at 298.15 K.
Aparna Banerjee, Ziley Singh Chaudhary, Materials Chemistry and Physics 142 (2013) 12-16

B3349 – Heat capacities of several Co2YZ Heusler compounds

Heat contents of several Co2-based Heusler compounds Co2YZ (Y = Fe, Mn, Ti; Z = Al, Ga, Si, Ge, Sn) were measured from 500 K to 1500 K using a Setaram MTHC 96 drop calorimeter. Second order polynomials were adopted to fit the data and heat capacities were obtained by taking the derivatives with respect to temperature. Melting points were determined by differential scanning calorimetry (DSC) and measured heats of fusion were compared with those obtained from extrapolation of heat contents
Ming Yin, Philip Nash, Song Chen, Thermochimica Acta 574 (2013) 79– 84

B3359 – Solid oxide electrochemical cell and differential scanning calorimetry used for thermodynamic measurements of the ternary oxides: Nd2RuO5(s) and Nd2Ru2O7(s)

The standard molar Gibbs free energy of formation of Nd2RuO5(s) and Nd2Ru2O7(s) was determined using an oxide solid-state electrochemical cell wherein calcia stabilized zirconia (CSZ) was used as an electrolyte. The standard molar Gibbs free energy of formation of Nd2RuO5(s) and Nd2Ru2O7(s) from elements in their standard state was calculated by the least squares regression analysis of the data obtained in the present study and can be given respectively by: {?fGo(Nd2RuO5, s)/(kJ mol?1) ± 1.55} = ?2130.29 + 0.4786·(T/K); {?fGo(Nd2Ru2O7, s)/(kJ mol?1) ± 2.2} = ?2501.1 + 0.692·(T/K). Standard molar heat capacity Cop,m(T) of Nd2Ru2O7(s) was measured using a heat flux type differential scanning calorimeter (DSC) in two different temperature ranges, from 127 K to 299 K and 307 K to 745 K. The heat capacity of Nd2Ru2O7(s) was used along with the data obtained from the oxide electrochemical cell to calculate the standard enthalpy and entropy of formation of the compound from elements at 298.15 K.
Aparna Banerjee, Ziley Singh Chaudhary, Materials Chemistry and Physics 138 (2013) 417-422

B3358 – On the correlation between hydrogen bonding and melting points in the inositols

Inositol, 1,2,3,4,5,6-hexahydroxycyclohexane, exists in nine stereoisomers with different crystal structures and melting points. In a previous paper on the relationship between the melting points of the inositols and the hydrogen-bonding patterns in their crystal structures [Simperler et al. (2006). CrystEngComm 8, 589], it was noted that although all inositol crystal structures known at that time contained 12 hydrogen bonds per molecule, their melting points span a large range of about 170 °C. Our preliminary investigations suggested that the highest melting point must be corrected for the effect of molecular symmetry, and that the three lowest melting points may need to be revised. This prompted a full investigation, with additional experiments on six of the nine inositols. Thirteen new phases were discovered; for all of these their crystal structures were examined. The crystal structures of eight ordered phases could be determined, of which seven were obtained from laboratory X-ray powder diffraction data. Five additional phases turned out to be rotator phases and only their unit cells could be determined. Two previously unknown melting points were measured, as well as most enthalpies of melting. Several previously reported melting points were shown to be solid-to-solid phase transitions or decomposition points. Our experiments have revealed a complex picture of phases, rotator phases and phase transitions, in which a simple correlation between melting points and hydrogen-bonding patterns is not feasible
Sandor L. Beko, Edith Alig, Martin U. Schmidt, Jacco van de Streek, IUCrJ (2014). 1, 61–73

B3357 – Ordered mesoporous silica and aluminosilicate-type matrix for amikacin delivery systems

Amikacin, which belong to aminoglycosides class of antibiotics, was used to obtain drug delivery systems based on MCM-41-type supports. In order to study the factors that influence the adsorption and in vitro release of amikacin, a series of mesostructured silica and aluminosilicates were employed as carriers. The toxicity of the supports was evaluated by proliferation tests on murine fibroblastic cells (3T3) and no significant toxic effect was observed. Small-angle and wide-angle X-ray diffraction data, N2 adsorption/desorption isotherms, as well as DSC analyses proved the presence of drug molecules in amorphous state into the channels of mesostructured MCM-41-type supports. It was found that the amikacin uptake depends mainly on the total pore volume of the carrier. The aluminum content in the mesostructured matrix with average pore size smaller than 2.4 nm is favorable to the drug uptake. In vitro release profiles in phosphate buffer solution, pH 7.4, exhibited a burst effect of 40% drug in the first hour of the assay, followed by a slow rate of amikacin delivery. Slower release kinetics and a lower amikacin cumulative release amount from mesostructured aluminosilicates than silica carriers were noticed.
Silviu Nastase, Laura Bajenaru, Cristian Matei, Raul Augustin Mitran, Daniela Berger, Microporous and Mesoporous Materials 182 (2013) 32–39

B3356 – Biocompatible choline based ionic salts: Solubility in short-chain alcohols

In this work, we report data on solubility of choline chloride and choline acetate in short-chain linear alcohols (ethanol, 1-propanol and 1-butanol) at various temperatures. Furthermore, we synthesize two choline derivatives: hydrogen choline chloride glutarate ([CholGlut][Cl]) and hydrogen choline chloride succinate ([CholSucc][Cl]). Their characterization and solubility in short-chain alcohols as a function of temperature are also included. Activity coefficients were calculated and their comparisons with ideal solutions were discussed. The experimental data were correlated successfully by means of the semi-empirical Grant equation
Joana M. Lopes, Ana B. Paninhoa, Marta F. Môlho, Ana V.M. Nunes, Angelo Rocha, Nuno M.T. Lourenço, Vesna Najdanovic-Visak, J. Chem. Thermodynamics 67 (2013) 99–105

B3355 – System Er–Ru–O: High temperature study of the heavy rare earth pyrochlore Er2Ru2O7(s) by electrochemical cell and differential scanning calorimeter

The Gibbs free energy of formation of Er2Ru2O7(s) has been determined using solid-state electrochemical technique employing oxide ion conducting electrolyte. The reversible electromotive force (e.m.f.) of the following solid-state electrochemical cell has been measured. Standard molar heat capacity C°p,m(T) of Er2Ru2O7(s) was measured using a heat flux type differential scanning calorimeter (DSC) in two different temperature ranges, from 129 K to 296 K and 307 K to 845 K. The heat capacity in the higher temperature range was fitted into a polynomial expression.
Aparna Banerjee, Solid State Ionics 253 (2013) 70–75

B3354 – Enhanced water-solubility of Licorice extract microparticle prepared by antisolvent precipitation process

In this study, Licorice extract (LE) microparticles were successfully prepared using antisolvent precipitation process. Ethyl acetate and dimethyl sulfoxide, were used as the antisolvent and solvent, respectively. By means of orthogonal experimental design, the influences of several process parameters on the mean particle size (MPS) were investigated. The concentration range of the LE solution, the volume ratio of solvent to antisolvent, dripping speed, and temperature were 4.3–34.5 mg/mL, 1:1–1:12, 1–10 mL/min, and 20–35 °C, respectively. Based on the above orthogonal experiments, the optimum antisolvent precipitation process conditions were found to be: temperature 20 °C, concentration of the LE solution 17.2 mg/mL, volume ratio of solvent to antisolvent 1:4, dripping speed 10 mL/min. The LE microparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TG), differential scanning calorimetry (DSC), HPLC analysis and dissolution test. And the morphology, crystalline state and chemical structure, drug purity, dissolution rate and bioavailability of LE microparticles were investigated. Under optimum antisolvent precipitation process conditions, the MPS of LE microparticles reached to 85.3 nm, and with uniform distribution. And the LE microparticles had the same chemical structure as the unprocessed drug, but the crystallinity was reduced, purity was increased. Furthermore, the water solubility increased from 4.82 mg/mL to 16.10 mg/mL, and bioavailability is increased by 64.36%.
Chang Zu, Xiaowei Du, Xiuhua Zhao, Advanced Powder Technology (2013)

B3353 – Granular Cork Content Dependence of Thermal Diffusivity, Thermal Conductivity and Heat Capacity of the Composite Material/Granular Cork Bound with Plaster

This work is a contribution to understand the thermal behavior of the composite material based on granular cork embedded in plaster. An experimental investigation of its thermal properties was mainly performed using the Flash method and the tiny Hot Plate method in steady state regime. This will allow compare its thermal properties with those of plaster for motivate the proposal that this composite will be used as false ceiling. A comparison of the energy performances of the composite material and plaster was made; it allows deducing a very interesting energy gain. The preliminary findings indicate the composite is better than plaster in term of thermal insulation, energy storage capacity and lightness
Abou-bakr Cherki, Abdelhamid Khabbazi, Benjamin Remy, Dominique Baillis, Energy Procedia 42 ( 2013 ) 83 – 92

B3352 – Efflorescence on the surface of beeswax seals: A calorimetric study

The surface of beeswax seals shows a tendency to become covered with a white crystallic layer, composed mainly of unsaturated hydrocarbons. In order to obtain deeper insight into the nature of this adverse phenomenon, the thermal properties of the efflorescence and the pseudobinary mixtures efflorescence/beeswax were studied employing DSC and FTIR methods. The results are in agreement with the hypothesis that a primary cause of the problem is the limited miscibility of both pseudocomponents. Although a certain amount of alkenes can be “tolerated” in recrystallized beeswax, the resulting mixture is metastable. The possible delayed crystallization of alkenes is then connected with the development of the efflorescence. An understanding of the problem is important for suggesting reasonable conservation measures.
Benjamin Bartl, Jakub Havlín, Jirí Trejbal, Michal Durovic, Thermochimica Acta 566 (2013) 292– 297

E0083 – Polymorphism of Ca3SiO4Cl2 – DTA studies

The studies of calcium chlorosilicate Ca3SiO4Cl2 phase transition by DTA and high temperature calorimetry have been carried out. The temperature of transition as well as heat transition have been elucidated.
K. Miskiewicz and M. Pyzalski, Cement and Concrete Research 18 (1988) 819-822

B3362 – Mitigation of diabetes-related complications in implanted collagen and elastin scaffolds using matrix-binding polyphenol

There is a major need for scaffold-based tissue engineered vascular grafts and heart valves with long-term patency and durability to be used in diabetic cardiovascular patients. We hypothesized that diabetes, by virtue of glycoxidation reactions, can directly crosslink implanted scaffolds, drastically altering their properties. In order to investigate the fate of tissue engineered scaffolds in diabetic conditions, we prepared valvular collagen scaffolds and arterial elastin scaffolds by decellularization and implanted them subdermally in diabetic rats. Both types of scaffolds exhibited significant levels of advanced glycation end products (AGEs), chemical crosslinking and stiffening -alterations which are not favorable for cardiovascular tissue engineering. Pre-implantation treatment of collagen and elastin scaffolds with penta-galloyl glucose (PGG), an antioxidant and matrix-binding polyphenol, chemically stabilized the scaffolds, reduced their enzymatic degradation, and protected them from diabetes-related complications by reduction of scaffold-bound AGE levels. PGG-treated scaffolds resisted diabetes-induced crosslinking and stiffening, were protected from calcification, and exhibited controlled remodeling in vivo, thereby supporting future use of diabetes-resistant scaffolds for cardiovascular tissue engineering in patients with diabetes.
James P. Chow, Dan T. Simionescu, Harleigh Warner, Bo Wang, Sourav S. Patnaik, Jun Liao, Agneta Simionescu, Biomaterials 34 (2013) 685-695

E0082 – The dehydroxylation of aluminium hydroxides and the kinetics of alpha-Al2O3 formation

Studies were made of the dehydroxylation of several aluminium hydroxide modifications and the kinetics of alpha-Al2O3 formation. The investigated samples differed in both mineral composition and the level of alkali admixtures. It was found that the rate of formation and the quantity of alpha-Al2O3 depend mainly on the purity of the aluminium hydroxides, while the transition forms of alumina depend on the initial type of the aluminium hydroxide.
M. Pyzalski and M. Wojcik, Journal of Thermal Analysis 36 (1990) 2147-2151

B3361 – On the crystallization behavior of syndiotactic-b-atactic polystyrene stereodiblock copolymers, atactic/syndiotactic polystyrene blends, and aPS/sPS blends modified with sPS-b-aPS

Crystallization and morphological features of syndiotactic-b-atactic polystyrene stereodiblock copolymers (sPS-b-aPS), atactic/syndiotactic polystyrene blends (aPS/sPS), and aPS/sPS blends modified with sPS-b-aPS, with different compositions in aPS and sPS, have been investigated using differential scanning calorimetry (DSC), polarized light optical microscopy (POM) and wide angle X-ray diffraction (WAXRD) techniques. For comparative purposes, the properties of parent pristine sPS samples were also studied. WAXRD analyses revealed for all the samples, independently from their composition (aPS/sPS ratio) and structure (blends, block copolymers, blends modified with block copolymers), the same polymorphic ? form of sPS. The molecular weight of aPS and sPS showed opposite effects on the crystallization of 50:50 aPS/sPS blends: the lower the molecular weight of aPS, the slower the crystallization while the lower the molecular weight of sPS, the faster the crystallization. DSC studies performed under both isothermal and non-isothermal conditions, independently confirmed by POM studies, led to a clear trend for the crystallization rate at a given sPS/aPS ratio (ca. 50:50 and 20:80): sPS homopolymers > sPS-b-aPS block copolymers ?sPS/aPS blends modified with sPS-b-aPS copolymers > sPS/aPS blends. Interestingly, sPS-b-aPS block copolymers not only crystallized faster than blends, but also affected positively the crystallization behavior of blends. At 50:50 sPS/aPS ratio, blends (Blend-2), block copolymers (Cop-1) and blends modified with block copolymers (Blend-2-mod) crystallized via spherulitic crystalline growth controlled by an interfacial process. In all cases, an instantaneous nucleation was observed. The density of nuclei in block copolymers (160,000?190,000 nuclei mm?3) was always higher than that in blends and modified blends (30,000?60,000 nuclei mm?3), even for quite different sPS/aPS ratio. At 20:80 sPS/aPS ratio, the block copolymers (Cop-2) preserved the same crystallization mechanism than at 45:55 ratio (Cop-1). On the other hand, the 20:80 sPS/aPS blend (Blend-4) and blend modified with block copolymers (Blend-4-mod) showed a spinodal decomposition.
Liana Annunziata, Bernard Monasse, Paola Rizzo, Gaetano Guerra, Michel Duc, Jean-François Carpentier, Materials Chemistry and Physics 141 (2013) 891e902

E0081 – DTA studies of 12CaO,7Al2O3 polymorphism

The polymorphism of 12CaO.7AI203 has been studied by means of a Setaram G-24 thermoanalyser and by X-ray diffraction using a Philips diffractometer. Thermal treatment was carried out at 1.3 Pa as well as in air atmosphere.
M. Pyzalski, Z. Konik, J. Iwanciw and A. Stock, Journal of Thermal Analysis 32 (1987) 1727-1729

E0080 – Reaction between carbon fibres and molten silicon: heat determination using DTA

The highly exothermic reaction between carbon fibres and molten silicon, which is the basis of SiC--Si composite production, was investigated using a Setararn 2000 K thermoanalyser. DTA curves were recorded in 1.3 Pa vacuum and up to 1770 K, i.e. under the conditions of composite production. The results allowed calculation of the heat of the reaction, which ranged from 91 to 115 k J/tool.
M. Pyzalski, J. Bialoskorski and E. Walasek, Journal of Thermal Analysis 31 (1986) 1193-1196

E0079 – Studies of the reaction between the amorphous carbon and silicon

The kinetic parameters and the mechanism of reaction carbon black-silicon was studied by DTA, QXRD and microscopic methods. The possibility of SiC micropowders production at temperatures below the melting point of silicon was proved.
J. Bialoskorski, M. Pyzalski and E. Walasek, Journal of Thermal Analysis 36 (1990) 2033-2036

E0077 – Heats and entropies of fusion of ABC2 chalcopyrite semiconductors

Using quantitative DTA the melting temperatures and the enthalpies of fusion of some A(I)B(III)C(VI), and A(II)B(IV)C(V), compoundsare measured. The entropies of fusion are calculated and discussed in terms of the dielectric theory, and with regard to the structure of the liquid phase.
G. Kuhn, W. Moller and W. Engel, Thermochimica Acta 78 (1984) 129-134

E0076 – Phase interactions in silicon carbide reinforced composites.

Y. Bienvenu, J.C. Flour, Y. Favry, A.R. Bunsell, 7th International Conference "The materials revolution through the 90's", Paper 34

E0075 – Quelques possibilités d’application de l’analyse thermique différentielle pour l’étude de l’élaboration par la métallurgie des poudres

Y. Bienvenu, J.C. Le Flour, M. Jeandin

E0074 – Untersuchungen zum thermischen verhalten von NH4Al(SO4)2.12H2O

H-H. Emons, R. Naumann, K. Köhnke, Z. Anorg. Allg. Chem. 577 (1989) 83-92

E0092 – Thermoanalytical investigation of some alkaline earth hydroxide hydrates on application as latent heat storage materials

Owing to their high specific melting enthalpy and the range of the melting temperatures the alkaline-earth hydroxide hydrates Ba(OH)2.8H20 and Sr(OH)2.8H20 are promising latent heat storage materials. The investigations of the melting and solidification behaviour of Sr(OH)2.8H20 and its mixtures with Ba(OH)2.8H20, which had been performed by means of DTA and DSC methods in the closed system with a constant gross composition lead to statements on the melting temperature and specific melting enthalpy vs. concentration. Theoretical storage densities of 532 MJ/m 3 are obtained for the mixture of Ba(OH)2-8H20 and Sr(OH)2.8H20 (80/20) and a value of 655 MJ/m 3 can be achieved for Sr(OH)2.8H20. The kinetics of rehydration to the octahydrates has a great influence on the storage temperature and storage density.
R. Naumann and O. Schatz, Journal of Thermal Analysis 38 (1992) 665-671

E0073 – Thermoanalytical investigation of sodium acetate trihydrate for application as a latent heat thermal energy storage material

The thermal behaviour of sodium acetate trihydrate (NaAc. 3H20 ) was investigated by DTA, Q-TG and measurements of the solubility properties. The nucleation efficiency of Na4P207 9 10H20 for the crystallization of NaAc. 3H20 melts is not stable over lofig periods. Stratification can be ascribed to the formation of anhydrous sodium acetate in the supercooled melts. Under static heat storage conditions, NaAc- 3H20 and Na4P207 9 10H20 do not exhibit stable behaviour.
R. Naumann, Th. Fanghänel and H-H. Emons, Journal of Thermal Analysis 33 (1988) 685-688

E0087 – Etude par analyse thermique de trois matrices lipidiques

J. Kaloustian, A.M. Pauli, J. Pastor, P. Piccerelle, J. Joachim, JEEP (1992)

E0072 – Evolution thermique d’un gel de borosilicate de plomb.

W. Granier, K. Jabobker, M. Maurin, 16ème JEEP (1990) 47-52

E0114 – Thermodynamique des mélanges binaires LiPO3-Pb(PO3)2. Diagramme de phases et étude thermodynamique du liquide

Study of solid-liquid phase diagram of LiPO3-Pb(PO3)2 binary system, in certain calcination conditions, shows the existence of several metastable phasis. When heated at a temperature of 723 K the binary mixtures lead uncompletely to a defined compound Pb2Li(PO3). On heating these ternary solid mixtures, three eutectic reactions have been observed: (1) LiPO3+Pb(PO3)2Liquid at a temperature of 793 K (2) LiPO3+Pb2Li(PO3)5Liquid at a temperature of 843 K (3) Pb2Li(PO3)5+Pb(PO3)2Liquid at a temperature of 891 K The metastable liquid phase appears in the system at temperature of 793 K. DTA experiments performed on the binary LiPO3-Pb(PO3)2 mixtures, show a superposition of two diagrams. The first one is metastable and the second represents the stable equilibrium phase diagram. Measurements of liquid enthalpy of binary LiPO3-Pb(PO3)2 system at temperature of 979.65 K were reported. The corresponding values were very small and so the binary system can be considered as athermal. Assuming an ideal behaviour, the liquidus curves in the metastable diagram were calculated and the eutectic reaction (LiPO3-Pb(PO3)2Liquid) was confirmed at 793 K.
C. Marhag, H. Said, P. Satre, C. Favotto, J. Rogez, Journal of Thermal Analysis and Calorimetry 74 (2003) 275-285

E0102 – Thermal study of complex formation of triamterene with B-cyclodextrin by spray-drying and co-grinding

The formation of crystalline inclusion complex of triamterene with beta-cyclodextrin (beta-CD) was studied, evaluating the thermal behaviour and dispersion state of this drug in different types of binary systems. Spray-drying and co-grinding (oscillating mill) mixtures of triamterene with beta-CD were prepared in 1:1 molar ratio. The changes of crystalline properties of original (untreated) triamterene, beta-CD, and composites obtained by co-grinding and spray-drying were investigated in comparison with those produced in simple physical mixtures. The thermal behaviour of the different samples was investigated using DTA. X-ray diffraction was applied as a complementary technique. The results have been explained by formation of amorphous drug particles on spray-drying samples and co-grinding or alternatively by means of a solid dispersion formation or a combination of these two. A contamination effect by grinding media was also observed as increasing grinding time.
J.M. Ginés, M.J. Arias, C. Novak, P.J. Sanchez-Soto, A. Ruiz-Conde, E. Morillo, Journal of Thermal Analysis and Calorimetry 45 (1995) 659-666

E0124 – Equilibrium phase diagram of the Ag-Au-Pb ternary system

The phase diagram of the ternary system Ag-Au-Pb has been established using differential thermal analysis and X-ray powder diffraction analysis. Four vertical sections were studied: XPb = 0.40, XAu/XPb = 1/3, XAg/XAu = 4/1 and XAg/XAu = 1/1. Two ternary transitory peritectics and one ternary eutectic were characterized. A schematic representation of the ternary equilibria is given.
S. Hassam, Z. Bahari, Journal of Alloys and Compounds 392 (2005) 120-126

E0113 – Equilibres solide-liquide dans le système Al-Fe-Si

S. Pontevichi, M. Peronnet, F. Bosselet, J.C. Viala, J. Bouix, 28ème JEEP (2002)

E0101 – Determination of specific surface area of uranium oxide powders using differential thermal analysis technique

The two step oxidation of UO(2+x) and reduction of U3Os powders observed during Differential Thermal Analysis (DTA) has been exploited to determine their Speeifie Surface Areas (SSAs). The results obtained by this method have been compared with the Braunauer, Emmett and Teller (BET) method and are found to be in good agreement in the SSA range of 2-4 m2/gm in the ease of UO(2+x) obtained from ADU route and 4-8 m2/gm in the ease of AUC route. A precision of ± 0.1 m2/gm is obtained. The maximum temperature of oxidation and reduction of these oxides are dependent upon their preparative routes such as Ammonium Diuranate (ADU) and Ammonium Uranyl Carbonate (AUC).
Y. Balaji Rao, R.B. Yadav, R. Narazana Swamy, B. Gopalan, S. Syamsundar, Journal of Thermal Analysis and Calorimetry 44 (1995) 1439-1448

E0123 – Thermodynamic exploitation of the liquidus curves in the MIPO3-Pb(PO3)2, MIPO3-Cu(PO3)2 AND MIPO3-Ce(PO3)3 SYSTEMS(MI=Li, Na, K, Rb, Cs, Ag, Tl)

The thermodynamic exploitation of the solid-liquid equilibria in the M I PO3-Pb(PO3)2, M I PO3-Cu(PO3)2 and M I PO3-Ce(PO3)3 systems (with M I =Li, Na, K, Rb, Cs, Ag, Tl) is carried out using a semi-empirical equation of the liquidus curves already used with success for similar binary systems. The enthalpy of fusion is calculated for each pure polyphosphate on the assumption that the liquid solution is ideal and only formed by M I PO3 and M(PO3)q entities (q=2 for Pb and Cu, q=3 for M=Ce). In the most binary systems, a wide difference between the calculated values of the melting enthalpies of these polyphosphates and the measured ones determined from the DTA curves, was observed. This difference is probably due to the existence of some molecular associations in the liquid phase. The enthalpy of fusion of each terminal phase was then recalculated on the assumption that the liquid contains a molecular association of the type of M pn I Mn(PO3)n(q+p) in the region of the diagram rich in M I PO3 or a molecular association of the type of M n IMnp(PO3)n(qp+1) in the region rich in M(PO3)q (q=2 for Pb and Cu, q=3 for M=Ce). In this case, the obtained values are in good agreement with experimental determinations.
C. Marhag, D. Ben Hassen-Chehimi and H. Said, Journal of Thermal Analysis and Calorimetry 86 (2006) 249-254

E0112 – Thermal and structural studies of sodium borosilicate glasses containing thorium oxide

K. Sreejith, V. Sudarsan, R. Mishra, C.G.S. Pillai, Thermans (2002) 280-282

E0100 – The Ag + Au + Pb system : determination of the liquidus surface

The liquidus surface of the Ag + Au + Pb system has been determined by differential thermal analysis. In the temperature range 973-298 K, experiments were performed along the four following sections: = with 0
S. Hassan, M. Gambino, J.P. Bros, Thermochimica Acta 257 (1995) 83-92

E0122 – Characterisation of antibacterial copper releasing degradable phosphate glass fibres

Phosphate-based glass fibres (PGF) of the general formula Na2O-CaO-P2O5 are degradable in an aqueous environment, and therefore can function as antibacterial delivery systems through the inclusion of ions such as copper. In this study, PGF with varying amounts of copper oxide (CuO) were developed for potential uses in wound healing applications. PGF with 0, 1, 5 and 10mol% CuO were produced with different diameters and characterised in terms of structural and antibacterial properties. The effect of CuO and fibre pulling speed on the glass properties were investigated using rapid differential scanning calorimetry, differential thermal analysis and X-ray diffraction. The effect of two fibre diameters on short-term (3 h) attachment and killing against Staphylococcus epidermidis were investigated and were related to their rate of degradation in deionised water, as well as copper ion release measured using ion chromatography. Thermal analysis showed that there was a significant increase in the PGF glass transition temperature as the CuO content increased. There was a significant decrease in the rate of degradation with increasing CuO content and an increase in fibre diameter. Over 6 h, both the amount and rate of copper ions released increased with CuO content, as well as a reduction in fibre diameter thus increasing the surface area to volume ratio. There was a decrease in the number of viable staphylococci both attached to the CuOcontaining fibres and in the surrounding environment.
E.A. Abou Neel, I. Ahmed, J. Pratten, S.N. Nazhat, J.C. Knowles, Biomaterials 26 (2005) 2247-2254

E0111 – Etude du systeme LiPO3-Pr(PO3)3 données sur LiPr(PO3)4

The LiPO3-Pr(PO3)3 system was studied by micro-differential thermal analysis. The only new compound observed in the system was LiPr(PO3)4, melting incongruently at 1246 K. An eutectic appears at 926 K. Crystallographic data and powder diagram of the new compound are given. LiPr(PO3)4 crystallizes in the C2/c monoclinic system with unit cell: a=16.428(6), b=7.054(3), c=9.747(4) , =126°31(3), V=910.2 3, Z=4. The IR and Raman spectra of this compound are given.
M. Ferid, B. Piriou and M. Trabelsi-Ayedi, Journal of Thermal Analysis and Calorimetry 53 (1998) 227-234

E0099 – Bi, Pb(2212) and Bi(2223) formation in the Bi-Pb-Sr-Ca-Cu-O system

A new route has been found for producing the Bi2Sr2CaCu2Oy, phase with Pb substituted for part of the Bi (denoted Bi,Pb(2212)). By this novel route, Bi,Pb(2212) has been prepared in air at 860 degrees C. For comparison, this phase has also been prepared in argon at 740 degrees C by the previously known route. Bi,Pb(2212) transforms from a tetragonal to an orthorhombic structure as the Pb content grows. Once this phase was obtained with a nominal composition of Bi(2-x)PbxSr2CaCu2Oy, with Pb contents x=0, 0.2, 0.4 and 0.6, the Bi(2223) phase was formed starting from Bi(2212) and Bi,Pb(2212). Single-phase samples were obtained after two heat treatments at 849 degrees C with Bi,Pb(2212) and a proportion of Pb of x=0.4. This proportion corresponds to the one used previously by the authors to obtain high critical current carrying tapes in Ag-clad Bi(2223) tapes.
A. Jeremie, K. Alami-Yadri, J-C. Grivel and R. Flükiger, Superconductor Science and Technology 6 (1993) 730-735

E0121 – Nominal vs. actual stoichiometries in Al-doped NASICONs: A study of the Na1.4Al0.4M1.6(PO4)3 (M=Ge, Sn, Ti, Hf, Zr) family

Nominal Na1.4Al0.4M1.6(PO4)3 (M=Ge, Sn, Ti, Hf, Zr) NASICON compounds have been prepared as polycrystalline powders. Rietveld analysis of X-ray and neutron diffraction patterns showed that M=Ge and Sn samples crystallize in the R3¯ space group (s.g.) and that M=Ti, Hf, Zr compositions crystallize in the R3¯c s.g. Data analyses indicated that aluminum contents into the main NASICON phases are always smaller than the nominal ones. 27Al, 31P and 23Na magic angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopies have been used to deduce aluminum contents and local atomic environments. In samples with high aluminum contents, M=Ge, Sn and Ti, electrical conductivity has been deduced from impedance spectroscopy data. The titanium sample incorporates the maximum aluminum content and displays the lowest activation energy, 0.52(1) eV, and the highest conductivity, rT(400 K)=1.5(3) 10 5 S cm 1. The influence of structural parameters on conductivity values has been analyzed with the bond valence sum method. With this technique, the most probable conduction pathways in Na1+xAlxTi2 x(PO4)3 and Na1+xInxZr2 x(PO4)3 samples have also been deduced.
P. Maldonado-Manso, M.A.G. Aranda, S. Bruque, J. Sanz, E.R. Losilla, Solid State Ionics 176 (2005) 1613 - 1625

E0110 – Thermodynamic study of the solid-liquid equilibria in the systems MPO3-Pr(PO3)3 (M=Na, Rb, Cs or Ag)

A previously established equation of a stoichiometric phase liquidus curve was applied to determination of the phase diagrams of the systems MIPO3-Pr(PO3)3 (with MI=Na, Rb, Cs or Ag). The temperature, enthalpy and entropy of fusion were calculated for each solid phase with the exception of silver polyphosphate, the crystallization field of which was very limited. The enthalpy of fusion of the polyphosphate Pr(PO3)3 was determined from the DTA curve. The melting enthalpy of Pr(PO3)3 calculated from the different binary systems was approximately equal to the measured value. The calculated temperatures and compositions were in good agreement with those determined experimentally.
D. Ben Hassen-Chehimi, N. Kbir-Ariguib and M. Trabelsi-Ayedi, Journal of Thermal Analysis and Calorimetry 53 (1998) 871-882

E0097 – Phase transitions of Li2ZrO3 and Li4SiO4 at high temperature

T. Tatsuya, M. Tsuneo, JSCTA 104-105

E0120 – Crystal structures of Rb2U2O7 and Rb8U9O31, a new layered rubidium uranate

Two alkali metal uranates Rb2U2O7 and Rb8U9O31 have been synthesized by solid state reaction at high temperature and their crystal structures determined from single crystal X-ray diffraction data, collected with a three circles Brucker SMART diffractometer equipped by Mo(Ka) radiation and a charge-coupled device (CCD) detector. Their structures were solved using direct methods and Fourier difference techniques and refined by a least-square method on the basis of F2 for all unique reflections, with R1 = 0,043 for 53 parameters and 746 independent reflections with I>2?(I) for Rb2U2O7, monoclinic symmetry, space group P21/c, a = 7,323(2) Å, b = 8,004(3) Å, c = 6,950(2) Å, beta = 108,81(1)°, pmes = 6,56(3) g/cm3, pcal = 6,54(2) g/cm3, Z = 2 and R1 = 0,036 for 141 parameters and 2065 independent reflections with I>2?(I) for Rb8U9O31, orthorhombic, space group Pbna, a = 6,9925(9) Å, b = 14,288(2) Å, c = 34,062(5) Å, pmes = 6,47(3) g/cm3, pcal = 6,48(2) g/cm3, Z = 4. The Rb2U2O7 structure presents a strong analogy with that of K2U2O7 and can be described by layers of distorted UO2(O4) octahedra built from dimeric units of edge shared octahedra further linked together by opposite corners. In Rb8U9O31 puckered layers are formed by the association of two different uranium polyhedra, pentagonal bipyramids and distorted octahedra. The structure of Rb8U9O31 is built from a regular succession of 1[U4O14] 4- infinite ribbons similar to those observed in diuranates M2U2O7 (MQK, Rb) and infinite three polyhedra wide ribbons 1[U5O21] 12- , to create an original undulated sheets 2[U9O31] 8- . For both compounds Rb+ ions occupy the interlayer space and exhibit comparable mobility with conductivity measurements indicating an Arrhenius-type behavior.
S. Yagoubi, S. Obbade, C. Dion, F. Abraham, Journal of Solid State Chemistry 178 (2005) 3218-32

E0109 – DSC Study of Y(a)Ba(b)Cu(c)O(7-d) homogeneity in the region 1050-1300K

Phase transitions of the compositions Y1±xBa2±yCu3±zO72212; (x,y=0-0.2;z=0-0.5; step 0.1) were studied by DSC in argon atmosphere in the temperature range 1050-1300 K. The formation of three polymorphous modifications of the 123 phase was observed. The solubilities of yttrium, barium and copper oxides in every modification were determined. TheT-x-y phase microdiagram for the 123 phase was mapped out.
K.S. Gavrichev, A.V. Khoroshilov, G.D. Nipan and P. Manca, Journal of Thermal Analysis and Calorimetry 48 (1997) 1039-1050

E0096 – Thermal analysis of new glass ceramic composite tapes and their components

Glass ceramic tapes prepared from various AlN, glass and organic binders were studied by simultaneous TG-DTA. Thermooxidative decomposition of polymeric binder, dehydration, oxidation of residual carbon, glass crystallization and oxidation of AlN were detected and evaluated. Results are compared with those obtained with the pure components AlN and glass. The rate of oxidation of various AlN charges at> 800°C in an air flow depends on their specific surface and eventual special (antihydrolytic) coating. In the ceramic composite the oxidation of AlN is much slower than in free AlN powder because of the embedding in the glass matrix. The glass exhibits crystallization to cordierite, the crystallization rate and final crystallinity depending on the P2O5 and B2O3 contents and the particle size of the glass. In the composite the crystallization of the glass component is accelerated and proceeds to a higher degree owing to the smaller particle size and to interactions between glass and filler. Grinding of the ceramic raw mix results in additional adsorption of moisture.
D. Schultze, W. Schiller and E. Schiller, Thermochimica Acta 246 (1994) 81-97

E0119 – Crystallization in the Na2O-CaO-Al2O3-SiO2-(LiF) glass compositions

Spodumene-nepheline glass-ceramics was prepared from Na2O-CaO-Al2O3-SiO2 glass compositions. Addition of LiF changes the course of the reaction toward the formation of beta-spodumene together with nepheline. The crystallization of beta-spodumene strongly reduce
E.M.A. Hamzawy, E.M. El-Meliegy, Ceramics International 33 (2007) 227-231

E0108 – Determination of phase diagrams by heat evaluation from DTA.

Basing on a quantitative analysis of DTA heat flow measurements the compositions of eutectic and peritectic reactions in complicated systems can be sensitively determined. In addition to the conventionally used DTA onset temperatures, the quantitative analysis of the corresponding heat flows provides important further information which significantly improve the determination of phase relations in complicated systems. The general concept is demonstrated for simple model systems. The sensitivity of detection and the separability of the DTA events will be discussed in detail. The applicability of the method is proved for two complicated examples from the Y---Ba---Cu---O system: (1) the quasibinary section YBa2Cu3O7 - delta---BaCuO2 and (2) the ternary eutectics YBa2Cu3O7 - delta---bBaCuO2---bCuO.
U. Wiesner, W. Bieger and G. Krabbes, Thermochimica Acta 290 (1996) 115-121

E0095 – Analyse thermique de mélanges binaires : matrice lipidique (15%) – Principe actif (85%)

J. Kaloustian, A.M. Pauli, J. Pastor, JEEP (1994) 47-48

E0118 – A comparative study of the dehydroxylation process in untreated and hydrazine-deintercalated dickite

A dickite from Tarifa (Spain) was used to study the influence of the intercalation and the later deintercalation of hydrazine on the dehydroxylation process. The dehydroxylation of the untreated dickite occurs through three overlapping endothermic stages whose DTA peaks are centred at 586, 657 and 676°C. These endothermic effects correspond, respectively, to the loss of the inner-surface, the inner hydroxyl groups, and the loss of the water molecules, product of dehydroxylation process, which has been trapped in the framework of the dehydroxylated dickite. The intercalation of hydrazine in the interlayer space of dickite and the later deintercalation affect the dehydroxylation process. It occurs through only two endothermic stages which DTA peaks are centred at 575 and 650°C. The first corresponds to the simultaneous loss of both the inner and the inner-surface hydroxyl groups, whereas the second one is analogous to that at 676°C observed in the DTA curve of untreated dickite. These effects appear shifted to lower temperatures compared to those observed in the untreated dickite.
F. Franco and M.D. Ruiz Cruz, Journal of Thermal Analysis and Calorimetry 85 (2006) 369-375

E0107 – The ruthenium-tin system.

The Ru---Sn liquid-solid and some solid-solid equilibria have been completely revised by means of differential thermal analysis, X-ray powder diffraction and microprobe investigations. The existence of two intermetallic phases has been clearly established: Ru0.4Sn0.6 decomposed by a peritectic reaction at 1266(± 4)°C and Ru0.1Sn0 - congruently melting at 1257(± 2)°C.
L. Perring, P. Feschotte, F. Bussy and J.C. Gachon, Journal of Alloys and Compounds 245 (1996) 157-163

E0093 – Melting of forsterite and spinel, with implications for the glass transition of Mg2SiO4 liquid

P. Richet, F. Leclerc, L. Benoist, Geophysical Research Letters 20 (1993) 1675-1678

E0117 – Contribution à l’étude du système quasi-binaire ZrAu-CeAu

A. Ait Chaou, M. Lomello-Tafin, P. Lejay, J. Allemand, Ph. Galez, 30ieme JEEP (2005) 87-88

E0106 – The germanium-ruthenium system.

L. Perring, P. Feschotte and J.C. Gachon, Journal of Phase Equilibria 17 (1996) 101-106

E0116 – Phases and phase equilibria in the Fe-Al-Zr system

F. Stein, G. Sauthoff, M. Palm, Z. Metallkd. 95 (2004) 469-485

E0105 – Brasage d’aciers réfractaires par des poudres de brasage à base de nickel.

J.D. Bartout, Y. Bienvenu, A. Germidis and J. Favennec

E0115 – Thermodynamic study of the solid-liquid equilibria in the MPO3-Cu(PO3)2 systems

Thermodynamic exploration of solid-liquid equilibria of the MIPO3-Cu(PO3)2 (with MI=Li, Na, K, Rb, Cs, Ag, Tl) systems is carried out with a semi-empirical equation of the liquidus curves. The enthalpies of fusion of pure polyphosphates and some intermediate compounds were determined from DTA curves. The temperature, enthalpy and entropy of fusion are calculated for each solid phase with the exception of silver polyphosphate and the intermediate compound Cs4Cu(PO3)6 which have very limited crystallization fields. The calculated values of the melting enthalpies are approximately equal to the measured ones. The melting enthalpy of Cu(PO3)2 calculated from different binary systems shows a wide variation in the obtained values, 35-54 kJ mol-1. The experimental value is 33.65 kJ mol-1. The calculated temperatures and compositions in most binary systems are in good agreement with experimental determinations.
C. Marhag, D.B. Hassen-Chehimi, H. Said, Journal of Thermal Analysis and Calorimetry 76 (2004) 417-428

E0103 – Influence of different amounts of hematite seedings on the temperature of phase transformation of transition aluminas into corundum

Corundum (alpha-Al2O3) is the only stable oxide in the aluminium-oxygen system and is characterized by its high mechanical and chemical stability. But there are some problems in producing very fine corundum powders. Usually alpha-Al2O3 is obtained from transition aluminas at temperatures in the range of 1100-1200°C. At this temperatures the dispersity of the corundum formed is reduced due to the start of grain growth processes. That is the reason for our investigations in preparing alpha-Al2O3 at lower temperatures. Therefore aluminium-secondary-butoxide was hydrolysed in water and seeded with different amounts of hematite. The dried powders were investigated for instance by using differential thermal analysis. A nearly linear relation between seeding amount and transformation temperature was found. The formation temperature of corundum was decreased by seeding with 10 wt% hematite from about 1100 to 970°C.
Th. Oberbach, C. Günther, G. Werner, G. Tomandl and G. Wolf, Thermochimica Acta 271 (1996) 155-162

E0125 – Delineation of phase fields at the Te-rich end of the Ru-Te binary system

The tellurium rich side of the ruthenium-tellurium binary system was studied by differential thermal analysis. To avoid reported problems of Te loss by evaporation and reactive interference of Te to the thermocouples of the thermal analyzer, the present study made use of specially designed sealed quartz capsules as DTA containers. The thermal analyses were carried out over the compositional range of 0.66 < xTe < 1.00 with the help of SETARAM TG/DTA and other indigenously built thermal analyzers available in this laboratory. The thermal data generated for fifteen different compositions were interpreted for the nature of phase transitions occurring at their characteristic temperatures. The Ru-Te binary system was found to have a eutectic transformation at 444°C at a composition of xTe = 0.918 and a monotectic transformation at 447°C at a composition of xTe = 0.700. Up to 6 at.% Ru is soluble in Te at about 440°C.
M. Ali (Basu), S.R. Bharadwaj, D. Das, Journal of Nuclear Materials 340 (2005) 214-218

E0135 – Low temperature synthesis of anorthite based glass-ceramics via sintering and crystallization of glass-powder compacts

Anorthite based glass-ceramics were synthesized. The investigated glass compositions are located close to the anorthite-rich corner of the fluorapatite-anorthite-diopside ternary system. Glass powder compacts with mean particle size of 2 and 10 µm were prepared. Sintering behaviour, crystallization and the properties of glass-ceramics were investigated between 800 and 950°C. In the case of specimens made from the finer particles, complete densification was achieved at a remarkably low temperature (825°C) and the highest mechanical strength was obtained at 850°C, but density significantly decreased at higher temperatures. The samples prepared from the larger particles exhibited higher values of density, shrinkage and bending strength within a wider temperature range (825-900°C). Anorthite was predominantly crystallized between 850 and 950°C, along with traces of fluorapatite. Diopside was detected only in the MgO richer compositions.
V.M.F. Marques, D.U. Tulyaganov, S. Agathopoulos, V.Kh. Gataullin, G.P. Kothiyal, J.M.F. Ferreira, Journal of the European Ceramic Society 26 (2006) 2503-2510

E0134 – Crystallization of lanthanum and yttrium aluminosilicate glasses

The crystallization behaviour of aluminosilicate glasses of lanthanum (LAS) and yttrium (YAS) containing 2-8 mol% of Ln2O3 (Ln = La or Y), 12-30 mol% of Al2O3, and 64-80 mol% of SiO2 has been studied by DTA, XRD and SEM-EDX analysis. X-ray diffraction results indicate the presence of the mullite phase and La2Si2O7 in the monoclinic high-temperature G form (group space P21/c) for the LAS glasses, and mullite y-Y2Si2O7 in the monoclinic structure (group space C2/ m) and a small amount of b-Y2Si2O7 in the orthorhombic structure (space group Pna2) for the YAS. For both cases, very little tridymite phase is observed. The results also show that the values of Tg for YAS are higher than those for LAS glasses. The crystallization of LAS glasses is more difficult than that of YAS. For all samples, we observed only one kind of mullite (Al/Si = 3.14).
N. Sadiki, J.P. Coutures, C. Fillet, J.L. Dussossoy, Journal of Nuclear Materials 348 (2006) 70-78

E0133 – Effect of ZrO2 nucleant on crystallisation behaviour, microstructure and magnetic properties of BaO-Fe2O3-B2O3-SiO2 glass ceramics

Differential thermal analysis, X-ray diffractometry and scanning electron microscopy with energy dispersive spectroscopy were used to study the crystallisation of glass ribbons with a composition of 35% BaO, 35% Fe2O3, 20% B2O3 and 10% SiO2 (mol%) with 1% ZrO2 added as a nucleant. The magnetic properties of ribbons prepared via cooling the melts between steel rollers were measured with a vibrating sample magnetometer. The addition of ZrO2 apparently resulted in a quite distinct glass-in glass phase separation in as prepared specimens, greatly affecting the nucleation process. Heat treatment of specimens at their DTA exo-peak temperature of 721°C led to the formation of BaFe12O19 and BaB2O4 as the only crystalline phases. The glass ribbons heat treated in one-stage exhibited a quite non-uniform distribution of particles exhibiting exagerated grain growth, while a two-stage heat treatment at 526 and 721°C for different time periods generally led to more uniform distribution of platelet particles. The values of saturation magnetisation of specimens were in the Ms = 23-29 emu/g range, while the coercivity values varied between Hc = 1800-3000 Oe.
M. Mirkazemi, V.K. Marghussian, A. Beitollahi, S.X. Dou, D. Wexler, K. Konstantinov, Ceramics International 33 (2007) 463-469

E0144 – X-ray diffraction, 119Sn Mössbauer and thermal study of SnSe-Bi2Se3 system

The phase equilibrium diagram of the SnSe-Bi2Se3 system has been re-investigated using X-ray powder diffraction, thermal analysis (DTA and DSC) and 119Sn Mössbauer spectroscopy data. It shows solid solutions based on Bi2Se3 and SnSe ( alpha and beta forms) and three intermediate phases: well-defined, SnBi4Se7, SnBi4Se7, and a new phase Sn2Bi2Se5. The new phase Sn2Bi2Se5 exists in the composition range 25-55 mol% Bi2Se3. Its structure is still under study. However, 119Sn Mössbauer spectroscopy study of the latter allowed to achieve a well knowledge of the local environment of tin atoms and could contribute to the actual structural study.
K. Adouby, M.L. Elidrissi Moubtassim, C.P. Vicente, J.C. Jumas, A.A. Touré, Journal of Alloys and Compounds xxx (2007) xxx-xxx

E0132 – Local and average atomic order of ion-conducting Bi0.775La0.225O1.5 studied by neutron scattering and reverse Monte Carlo simulations

Bi0.775La0.225O1.5 has been investigated by means of neutron scattering in combination with Rietveld refinement and reverse Monte Carlo (RMC) simulations to study the average and local atomic order of the material. At low temperature the crystallographic analysis shows a clear split of anionic positions similar to that reported for Sr doped bismuth oxides. Although this split appears to be absent in the average structure at high temperature, an even larger split of Bi-O local distances is found in the pair distribution function calculated from the RMC models. This latter feature can be indicative of a tendency to have similar oxygen environments for all Bi atoms at high temperature, as a precursor of the fluorite structure that is the stable phase at even higher temperatures.
A. Ahi, A. Mellergard, S-G. Eriksson, Solid State Ionics 177 (2006) 289-297

E0143 – Three-dimensional framework of uranium-centered polyhedra with non-intersecting channels in the uranyl oxy-vanadates A2(UO2)3(VO4)2O (A = Li, Na)

The uranyl vanadates A2(UO2)3(VO4)2O (A = Li, Na) have been synthesized by solid-state reaction and the structure of the Li compound was solved from single-crystal X-ray diffraction. The crystal structure is built from [UO5] 4- chains of edge-shared U(2)O7 pentagonal bipyramids alternatively parallel to a- and b-axis and further connected together to form a three-dimensional (3-D) arrangement. The perpendicular chains are hung on both sides of a sheet [(UO2)(VO4)2] 4- parallel to (001), formed by U(1)O6 square bipyramids connected by VO4 tetrahedra, and derived from the autunite-type sheet. The resulting 3-D framework creates nonintersecting channels running down the a- and b-axis formed by empty face-shared oxygen octahedra, the Li+ ions are displaced from the center of the channels and occupy the middle of one edge of the common face. The peculiar position of the Li+ ion together with the full occupancy explain the low conductivity of Li2(UO2)3(VO4)2O compared with that of Na(UO2)4(VO4)3 containing the same type of channels half occupied by Na+ ions in the octahedral sites. Crystallographic data for Li2(UO2)3(VO4)2O: tetragonal, space group I41/amd, a = 7,3303(5) Å, c = 24,653(3) Å, V = 1324,7(2) Å^3, Z = 4, Pmes = 5,32(2) g/cm3, Pcal = 5,36(3) g/cm3, full-matrix least-squares refinement basis on F² yielded, R1 = 0,032, wR2 = 0,085 for 37 refined parameters with 364 independent reflections with I>2s(I).
S. Obbade, L. Duvieubourg, C. Dion, F. Abraham, Journal of Solid State Chemistry 180 (2007) 866-872

E0131 – Evidence for the nucleation and epitaxial growth of Zn phyllosilicate on montmorillonite

Zinc uptake in suspensions (63.7 g L 1) ofMX80montmorillonite was investigated at pH4.0 and 7.3, a total Zn concentration ([Zn]total) of 500 lM, and dissolved Si concentrations ([Si]aq) of 70 and 500 lMin 0.5 MNaCl, by kinetics experiments and polarized extended Xray absorption fine structure (P-EXAFS) spectroscopy. Differential thermogravimetric analysis verified the cis-vacant character of the montmorillonite. No Zn uptake occurred at pH 4.0, confirming that cation exchange was hampered by the high ionic strength of the suspension. At pH 7.3 and low [Si]aq ( 70 lM), Zn uptake occurred rapidly during the first hour of reaction, and then leveled off to 50 lmol/g montmorillonite at 168 h. The uptake rate is consistent with Zn sorption on pH-dependent edge sites. At pH 7.3 and high [Si]aq ( 500 lM), the initial sorption rate was similar, but Zn sorption continued, reaching 130 lmol/g at 168 h, and was paralleled by Si uptake with a Si/Zn uptake ratio of 1.51(10), suggesting formation of a Zn (hydrous) silicate. P-EXAFS data indicated that the first oxygen coordination shell of sorbed Zn is split into two subshells at 1.97(2) and 2.08(3)-2.12(2) Å for all EXAFS samples. These two distances are assigned to a mixture of tetrahedral (IVZn) and octahedral (VIZn) Zn complexes. The proportion of IVZn was lower in the high [Si]aq samples and decreased with reaction time. Al low [Si]aq and 216 h of reaction, nearest cationic shells of 0.6(4) Al in the film plane and 0.5(4) Si out of the film plane were detected at 3.00(2) and 3.21(2) Å , respectively, and were interpreted as the formation of IVZn and VIZn mononuclear complexes at the edges of montmorillonite platelets, in structural continuity to the (Al, Mg) octahedral sheets. At high [Si]aq, in-plane Zn and Al and out-of-plane Si neighbors were detected at 4 h, indicating the formation of Zn phyllosilicate nuclei at the layer edges. At 313 h, Zn-Al pairs were no longer detected, and Zn atoms were surrounded on average by 3.4(5) in-plane Zn at 3.10(1) Å and 1.7(9) out-of-plane Si at 3.30(2) Å , supporting the precipitation of a Zn phyllosilicate. Thus, dioctahedral Al phyllosilicate may act as a nucleating surface for the heterogeneous formation of trioctahedral Zn phyllosilicate at [Si]aq relevant to natural systems.
M.L. Schlegel, A. Manceau, Geochimica et Cosmochimica Acta 70 (2006) 901-917

E0142 – Fabrication and characterization of Pb-free transparent dielectric layer for plasma display panel

Glasses within the Bi2O3-B2O3-BaO-ZnO system were examined as potential replacements for PbO-based glass frits with low firing temperatures. These frits are used in the transparent dielectric layer of plasma display panels (PDP). The glass transition temperature (Tg) of the prepared glasses varied between 450 and 460°C. These glasses display dynamic dielectric properties, high transparency and thermal expansion as well as matching well with substrate glass. The thermal coefficient of expansion (TCE) was with the desired range of 81-86.10^(-7)/K. Moreover, when the screen printed film was heat-treated at 570°C for 30 min, optical transmittance (83%), root-mean square (rms) roughness (177.6 Å ), dielectric constant (10.25) and withstand voltage (4.15 kV) satisfied the requirements necessary for transparent dielectric layers to be used in PDP applications.
J-Y. Song, S-Y. Choi, Displays 27 (2006) 112-116

E0130 – Chemical inhomogeneity of intermetallic phases precipitates formed during solidification of Al-Si alloys

In this work, the results of an examination of the solidification process of the AlSi6 and AlSi12 alloys as influenced by the content of the transition metals, Fe, Mn and Cr, are presented. The concentration of these elements in alloys prepared from pure components has been changed in the following range: Fe 0.5-3 wt.%, Mn 0-2 wt.% and Cr 0.3 wt.%. The thermal effects during solidification of alloys at a cooling rate of 3.3 K/min (between liquidus and solidus) connected with forming of structural components of alloy were determined. The temperature of the phase transformations was evaluated and correlated with chemical composition of alloys. It was stated that, on an average, an increase in Fe and Mn content of about 1 wt.% increases the temperature of primary proeutectic iron-bearing phase precipitation by about 40 K (in the examined range of the alloys compositions). By means of microscopic observations of the alloy microstructure, the morphology of the primary phase precipitates frozen at a chosen temperature was estimated. On the basis of the results of X-ray microanalysis (EDS), the chemical composition of the primary iron-bearing phases was analysed, and a relation among the components (i.e., Al, Si, Fe, Mn and Cr) was established. The sequence of microstructural component formation during solidification of the alloys examined was presented.
M. Warmuzek, W. Ratuszek, G. Sek-Sas, Materials Characterization 54 (2005) 31-40

E0141 – Preparation and characterization of CuO doped Bi2O3-B2O3-BaO-ZnO glass system for transparent dielectric layer

The electrical, thermal, optical, and morphological properties of CUO doped Bi2O3-B2O3-BaO-ZnO glasses were studied as a PbOfree, low firing transparent dielectric layer for plasma display panels (PDP). CuO improved the transmittance of Bi2O3-B2O3-BaO-ZnO by up to 84% in the visible region, eliminating a yellowish color typical of Bi2O3-B2O3-BaO-ZnO. A slight absorption within the near infrared (NIR) region was also observed. The glass transition temperature (Tg), thermal coefficient of expansion (TCE), and root-mean square (rms) roughness of 0.005 wt% CuO doped Bi2O3-B2O3-BaO-ZnO were found to be 455°C, 81.4 x 10^(-7)/K, respectively, and 162 ± 14 Å , which satisfied the requirements for a transparent dielectric layer for PDP application.
J-Y. Song, T-J. Park, S-Y. Choi, Journal of Non-Crystalline Solids 352 (2006) 5403-5407

E0129 – A study on colouration and axial variation of composition in the single crystal of lead tungstate grown by Czochralski technique

A thorough study reveals the importance of a proper synthesis condition in the growth of colour-free lead tungstate single crystals. An optimised synthesis scheme is described. The temperature gradient required, above the melt, for the growth of crack-free crystals is 25°C/cm. Differential thermal analysis shows that an improper synthesis results in a compositional variation along the vertical axis of the crystal. UV-visible absorption detects an enhanced absorption in the wavelength, 380-450nm for the pale yellow-coloured crystals. Annealing in air for 15 h at 1050°C removes the special blue absorption in the coloured crystal.
I. Bhaumik, S. Ganesamoorthy, A.K. Karnal, V.K. Wadhawan, Journal of Crystal Growth 275 (2005) e839-e842

E0140 – Thermomechanical characteristics of calcium aluminate cement and sand tapes prepared by tape casting

The present paper concerns the mechanical characterization of calcium aluminate cement and sand tapes prepared by tape casting, including ultrasonic measurements of Young's modulus at high temperature and evaluation of four point flexural behavior after heat treatments in the range of 20-1400°C. It is shown that dehydration strongly affects mechanical properties in the 400-900°C range, but that treatments at temperatures higher than 1200°C increase both Young's modulus and strength. By correlation with thermal and X-ray diffraction analyses, the evolutions of thermomechanical properties have been related to phase and microstructural changes when heating the material after hydration: conversion of hydrates and dehydration at low temperature, then, crystallization of C-A and C-A-S phases and finally sintering at the highest temperatures. In a last part, it is shown that the reinforcement by glass fibres enhances the mechanical properties, in particular in the temperature range of dehydration, and gives to the material a non-brittle behavior.
J. Soro, A. Smith, C. Gault, Journal of the European Ceramic Society 26 (2006) 3799-3807

E0128 – Selective oxidation of methanol to formaldehyde over V-Mg-O catalysts

The results of a complex investigation of V-Mg-O catalysts for oxidative dehydrogenation (ODH) of methanol are presented. The efficiency of vanadium-magnesium oxide catalysts in production of formaldehyde has been evaluated. Strong dependence of the formaldehyde yield and selectivity upon vanadium oxide loading and the conditions of heat treatment of the catalyst were observed. The parameters of the preparation mode for the efficient catalyst were identified. In optimised reaction conditions the V-Mg-O catalysts at the temperature approximate 450°C ensured the formation of formaldehyde with the yield of 94% at the selectivity of 97%. No visible changes in the performance of the catalyst (methanol conversion, formaldehyde yield and selectivity) were detected during the 60 h of operation in prolonged runs. Characterization of the catalyst by XRD, IR, and UV methods suggests the formation of species of the pyrovanadate type (Mg2V2O7) with irregular structure on the surface of a V-Mg-O catalyst. These species make the catalyst efficient for methanol ODH.
G.V. Isaguliants, I.P. Belomestnykh, Catalysis Today 100 (2005) 441-445