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5631 articles

B3201 – Preparation of highly loaded and dispersed Ni/SiO2 catalysts

A highly loaded and dispersed Ni/SiO2–B catalyst was prepared by the precipitation method with an n-butanol drying process. Drying with n-butanol significantly increased the surface area of the catalyst as well as the reducibility and dispersion of supported nickel, leading to the high active nickel surface area (66 m2/g-catalyst). In addition, the surface acidity of the Ni/SiO2-B catalyst was significantly enhanced, as probed by the microcalorimetric adsorption of ammonia. Accordingly, this catalyst adsorbed great amount of toluene with the high initial heat of about 140 kJ/mol, and exhibited high activity for the hydrogenation of toluene to methyl cyclohexane.
Mingwei Xue, Shenghua Hu, Hui Chen, Yuchuan Fu, Jianyi Shen, Catalysis Communications 12 (2011) 332–336

B3212 – Scale-up of Azide Chemistry: A Case Study

We report research and development conducted to enable the safe implementation of a highly enantioselective palladium-catalyzed desymmetrization of a meso–bis-ester using trimethylsilylazide (TMSN3) as the nucleophile. This work is used as a case example to discuss safe practices when considering the use of azide reagents or intermediates, with a focus on the thermodynamic and quantitative analysis of the hazards associated with hydrazoic acid (HN3).
Francisco Gonza?lez-Bobes, Nathaniel Kopp, Li Li, Joerg Deerberg, Praveen Sharma, Simon Leung, Merrill Davies, Joseph Bush, Jason Hamm, Michael Hrytsak, Org. Process Res. Dev. 2012, 16, 2051?2057

B3200 – Thermal stability of a low Tg phosphate glass investigated by DSC, XRD and solid state NMR

The thermal stability of a low Tg phosphate glass (Tg = 339 °C), formulated in the ZnO–Na2O–P2O5 system, is investigated in this contribution by Differential Scanning Calorimetry (DSC), X-Ray diffraction (XRD) and solid state Nuclear Magnetic Resonance (NMR). DSC measurement indicates a very important Tx ? Tg value (197 °C) for the investigated composition compared to other low Tg phosphate glasses found in literature. XRD and 1D 31P solid state NMR were used to monitor the isothermal crystallization process occurring at 60 °C above Tg (400 °C). The mixture of phases formed after crystallization cannot be identified by XRD but 2D MAS-NMR experiment provides valuable information about the composition and the structure of the unknown sample.
Grégory Tricot, Bertrand Revel, Sebastian Wegner, Journal of Non-Crystalline Solids 357 (2011) 2708–2712

B3222 – Structural perturbation of diphtheria toxoid upon adsorption to aluminium hydroxide adjuvant

Aluminium-containing adjuvants are often used to enhance the potency of vaccines. In the present work we studied whether adsorption of diphtheria toxoid to colloidal aluminium hydroxide induces conformational changes of the antigen. Diphtheria toxoid has a high affinity for the aluminium hydroxide particles based on a high adsorption degree, adsorption rate and adsorptive capacity. The conformation and stability of diphtheria toxoid in solution and adsorbed to aluminium hydroxide adjuvant were characterized using five physicochemical techniques: intrinsic and extrinsic fluorescence spectroscopy, circular dichroism, infrared spectroscopy and differential scanning calorimetry. Diphtheria toxoid adsorbed to aluminium hydroxide resulted in a minimal shift of the tryptophan fluorescence spectrum, whereas a large increase in the emission of the Bis-ANS probe was observed, indicating that hydrophobic sites of the protein became accessible due to adsorption. In addition, circular dichroism and infrared spectroscopy revealed that adsorption to aluminium hydroxide caused an increase of ?-sheet content and a decrease of ?-helix content in diphtheria toxoid. Differential scanning calorimetry demonstrated a major decrease in the enthalpy of denaturation upon adsorption. In conclusion, the adsorption of diphtheria toxoid to aluminium hydroxide adjuvant leads to substantial conformational changes in the antigen. Since physicochemical methods can be used to monitor these conformational changes, these analytical methods might offer a tool in regulatory required vaccine quality control by demonstrating consistency in production.
Marie Régnier, Bernard Metz, Wichard Tilstra, Coenraad Hendriksen, Wim Jiskoot, Willem Nordee, Gideon Kersten, Vaccine 30 (2012) 6783– 6788

B3232 – Numerical simulation of the cooling-down of high-zirconia fused-cast refractories

This study concerns high zirconia fused-cast refractories used in the glass industry. In situ temperature measurements have been performed in the casting structure during an actual casting of a tile. A two-dimensional mesh of the casting structure has been developed so as to perform numerical simulations. From temperature recordings, an interfacial heat transfer coefficient between the tile and the graphite mould has been determined, by an inverse method, by fitting the calculated temperatures with those measured. A similar procedure allowed the thermal conductivity and the heat capacity of the surrounding insulating medium to be determined. Then, the numerical model allowed the evolution of the temperature field, within the tile, to be determined. The influences of different parameters (mould thickness and thermal properties of the annealing medium) have been numerically tested, by comparison with the cooling-down kinetics of the tile
Laetitia Petroni, Michel Boussuge, David Ryckelynck, Journal of the European Ceramic Society 32 (2012) 3941–3947

B3231 – Investigation of the diffusion of dyes in agar gels

An experimental set-up and a measurement technique were developed so that diffusion in model foods (gels of agar) could be visualised and quantified. The diffusion of aqueous solutions of varying concentrations of two dyes (rhodamine 6G and methylene blue) in gels of agar was followed in situ at three temperatures (30, 50, 70 °C) until equilibrium was reached. The nature of the diffusion process (in terms of the amount of dye diffused into the gel) was studied using image analysis techniques. The diffusion coefficient, D, was estimated using Fick’s second law of diffusion and found to be ?10?10 m2 s?1. The effect of the size of the diffusing molecule, as well as that of the processing temperature on diffusion was investigated and found to be significant.
K. Samprovalaki, P.T. Robbins, P.J. Fryer, Journal of Food Engineering 111 (2012) 537–545

B3230 – Self-association of novel mixed 3-mono-O-alkyl cellulose: Effect of the hydrophobic moieties ratio

Heat-induced self-association of regioselectively functionalized 3-0-alkyl celluloses bearing both ethyl-and propyl groups dissolved in water was studied by means of differential scanning calorimetry and oscillatory shear rheology. The measured degrees of substitution were close to 1 but the ratio of ethyl (DSEt) to propyl groups (DSPr) was varied. The aggregation process is intimately coupled with phase separation as shown by the appearance of clouding in the same temperature range. Phase separation is arrested by the incipient gelation; whereby "stronger" gels are produced with high amounts of the propyl substituent than "weaker" phase separating samples as the amount of ethyl groups increases and the amount of propyl groups decreases. The correlation between rheology and thermal analysis clearly demonstrates that aggregation leads to formation of a gel network. It was found that as the ethyl moiety is replaced by propyl group the enthalpies of the thermal transitions increase strongly together with an increase of the elastic modulus (G') and the network is also more coherent with a steady decrease in tan ?(G"/G'). Reversibility was observed on cooling with a marked hysteresis for samples containing high levels of propyl groups. Hysteresis on cooling was explained in term of additional consolidation of the structure occurring at temperature much higher than the aggregation temperature, possibly involving backbone-backbone interactions. Quantitative analysis of the DSC data, based on the two-state thermodynamic model described by Armstrong et al. (1995) enabled evaluation of the van't Hoff enthalpy and the aggregation number. On the basis of those thermodynamic parameters, an "intermolecularly bridged clusters" model is proposed for the heat-induced transition of 3-0-ethyl-propyl cellulose ethers. The van't Hoff enthalpy/calorimetric enthalpy ratio ?HvH/?Hcal further indicates on the cooperativity of the process. The number of clusters and indeed the number of molecular chains comprising a cluster are both dependent upon the ratio of the two hydrophobic moieties. An increase in the aggregation number (n) (more aggregates coming together) occurs as ethyl is replaced by propyl, consistent with the observation of a "stronger" gel. The effect of the two different moieties on the physico-chemical properties of 3-0-ethyl-propyl cellulose ethers has been explained in term of different size/hydrophobicity of the two moieties and their distribution.
Antonio Sullo, Yunhui Wang, Andreas Koschella, Thomas Heinze, Tim J. Foster, Carbohydrate Polymers 93 (2013) 574– 581

B3229 – Characteristics, phase behavior and control release for copolymer–liposome with both pH and temperature sensitivities

A pH- and thermo-sensitive berberine hydrochloride liposome modified by the poly(N-isopropylacrylamide-co-methacrylic acid-co-octadecyl acrylate) was synthesized. The morphology and size were determined by atomic force microscope (AFM) and dynamic light scattering (DLS). The phase transition temperature (Tpm) and phase transition pH (pH*) of the copolymer–liposome were obtained by differential scanning calorimetry (DSC). The results indicate that the size of copolymer–liposome depends on the mass ratios of the copolymer to soya bean lecithin (SPC) and the solution pH value, and the size can reach a maximum value at phase transition pH (pH*). The Tpm and pH* were affected by the mass ratios of the copolymer to SPC and properties of the copolymer. The release of berberine hydrochloride (BH) from the copolymer–liposome was investigated and the maximum release of BH was caused at Tpm and pH* of the copolymer–liposome. The results illustrate that BH released from the liposome is due to the phase transition of the copolymer–liposome, where both Tpm and pH* were acted as switches of the phase transition, and both spacial and temporal releases can be carried out by adjusting the temperature, pH value and release time
Wenting Zhou, Xueqin An, Junzhi Wang, Weiguo Shen, Zhiyun Chen, Xiaoyong Wang, Colloids and Surfaces A: Physicochem. Eng. Aspects 395 (2012) 225– 232

B3228 – Functionality of pork meat proteins: Impact of sodium chloride and phosphates under high-pressure processing

The effect of high-pressure treatment (350 MPa, 6 min, 20 °C) combined with sodium chloride (1.5–3.0%) and phosphates (0.25–0.5%) on the texture, water retention, color and thermal properties was assessed in pork meat batters. A principal component analysis was used to identify the relationship between thermal denaturation and the functional properties of pork meat proteins. The hardening effect of high pressure was correlated with the appearance of a high-pressure-induced myofibrillar protein structure. The structure was destabilized by sodium chloride and phosphates, which counteracted the high-pressure effect on pork batter texture. Cooking yield and water-holding capacity were improved by the interaction between sodium chloride and phosphates under pressure. The interaction between high pressure, sodium chloride and phosphates also changed the color of the cooked pork meat batters. The modifications of these technological properties could be related to protein denaturation through the effects of high pressure, salt, phosphates and the appearance of a salt-induced component.
G. Villamonte, H. Simonin, F. Duranton, R. Chéret, M. de Lamballerie, Innovative Food Science and Emerging Technologies 18 (2013) 15–23

B3227 – Corona structure on demand: Tailor-made surface compartmentalization in worm-like micelles via random cocrystallization

We present a straightforward approach to well-defined 1D patchy particles utilizing crystallization-induced self-assembly. A polystyrene-block-polyethylene-block-poly(methyl methacrylate) (PS-b-PE-b-PMMA) triblock terpolymer is cocrystallized in a random fashion with a corresponding polystyrene-block-polyethylene-block-polystyrene (PS-b-PE-b-PS) triblock copolymer to yield worm-like crystalline-core micelles (wCCMs). Here, the corona composition (PMMA/PS fraction) can be easily adjusted via the amount of PS-b-PE-b-PMMA triblock terpolymer in the mixture and opens an easy access to wCCMs with tailor-made corona structures. Depending on the PMMA fraction, wCCMs with a mixed corona, spherical PMMA patches embedded in a continuous PS corona, as well as alternating PS and PMMA patches of almost equal size can be realized. Micelles prepared by cocrystallization show the same corona structure as those prepared from neat triblock terpolymers at identical corona composition. Thus, within a certain regime of desired corona compositions the laborious synthesis of new triblock terpolymers for every composition can be circumvented.
Joachim Schmelz, Holger Schmalz, Polymer 53 (2012) 4333-4337

B3226 – Pilot application of phase change slurry in a 5 m3 storage

Thermal storage can make an important contribution towards tackling the rise in energy consumption by balancing energy supply with demand. In buildings Phase Change Materials (PCMs) are increasingly being used to reduce the heating and cooling peak demand. Phase Change Slurries (PCSs) are heat transfer fluids, which consist of a latent heat component, a dispersed PCM, and a sensible heat component, a carrier fluid that provides fluidity. This combination of sensible and latent heat storage offers high heat storage capacity, while circumventing the low thermal conductivity problems associated with PCMs. The fluidity of PCSs enables pumping through pipes and the spatial separation of the heat transfer unit and storage tank. Thus PCS is an alternative to conventional single phase fluids. A new PCS was tested in a 5 m3 storage tank pilot application. Material properties, such as melting range, viscosity, density, enthalpy and particle diameter have been determined by laboratory measurements. Experimental investigations were conducted in a pilot application, in order to allow an energetic comparison of the two heat storage fluids, water as reference medium and PCS. Depending on the operation temperature range the tested PCS can store more than twice as much heat compared to water as conventional heat transfer fluid. Due to the higher viscosity the required pumping energy for PCS is around five times higher as compared with water.
Laura Vorbeck, Stefan Gschwander, Peter Thiel, Bruno Lüdemann, Peter Schossig, Applied Energy 109 (2013) 538–543

B3225 – Cell behavior on a CCN1 functionalized elastin-mimetic protein polymer

We report the design of an elastin-mimetic triblock copolymer with the ability to guide endothelial cell adhesion, spreading, and migration while maintaining the elastomeric properties of the protein polymer. The V2 ligand sequence from matricellular protein CCN1 (cysteine-rich 61, CYR61) was multimerized and cloned into elastin polymer LysB10, creating LysB10.V2. Cell adhesion studies demonstrated that a LysB10.V2 surface density of at least 40 pmol/cm2 was required to elicit cell attachment. Peptide blocking studies confirmed V2 specific engagement with integrin receptor ?v?3 (P < 0.05) and we observed the formation of actin stress fiber networks and vinculin clustering, characteristic of focal adhesion assembly. Haptotatic migration assays demonstrated the ability of LysB10.V2 surfaces to stimulate migration of endothelial cells (P < 0.05). Significantly, we illustrated the ability of LysB10.V2 to support a quiescent endothelium. The CCN1 molecule functions to support many key biological processes necessary for tissue repair and thus presents a promising target for bioengineering applications. Collectively, our results demonstrate the potential to harness CCN1 specific function in the design of new scaffold materials for applications in regenerative medicine.
Swathi Ravi, Carolyn A. Haller, Rory E. Sallach, Elliot L. Chaikof, Biomaterials 33 (2012) 2431-2438

B3235 – Influence of mechanical alloying conditions on amorphous phase formation in Fe67B33

Mechanical alloying of Fe67B33 mixture was carried out in a planetary ball mill. Variable milling parameters were a balls size, a milling atmosphere (Ar, He) and a filling ratio. Powders were characterized by X-ray diffraction analysis, electron scanning microscopy (SEM) and differential scanning calorimetry (DSC). It was found that balls temperature strongly affects the amorphous phase quantity: the use of atmosphere with higher thermal conductivity (He) and small balls noticeably increases the amorphous phase output. It was revealed by SEM that considerable part of boron particles survives in the course of the milling and their presence can be responsible for a broad exothermic effect on the DSC curves. The maximal volume fraction of amorphous phase was about 77% and its composition was evaluated as 20/22 at.% B.
T.A. Sviridova, E.V. Shelekhov, V.I. Bazilyan, T.R. Chueva, N.V. Shvyndina, N.P. Dyakonova, Journal of Alloys and Compounds (2012)

B3224 – Effect of composition of commercial whey protein preparations upon gelation at various pH values

The major goal of this research effort was to comprehensively characterize various whey protein products available in the market — including one whey protein isolate (WPI) and three whey protein concentrates (two forms of WPC 80, and WPC 50), with regard to the effects of specific components (e.g. lecithin and minerals) and concentration of ?-lactoglobulin (?-Lg) and ?-lactalbumin upon thermal and gelation properties at various pH values (using micro differential scanning calorimetry, ?DSC, and oscillatory rheometry). At pH values far from the isoelectric point of whey proteins, denaturation and aggregation appeared as one single endothermic peak in the corresponding ?DSC heating thermograms, for WPI and both WPC 80; however, they appeared as separate transitions at pH 5. Acidic conditions increased the temperature of occurrence of the dominant endothermic transition associated to ?-Lg, thus increasing the thermal stability of WPI, WPC 80A and WPC 80B. Gelation took place at the lowest temperature when pH was set at 5. WPI, WPC 80A and WPC 80B exhibited the highest G? values at pH 5 — whereas WPI led to stronger gels than WPC, irrespective of pH. In the case of WPC 50, gelation did not occur at all.
Óscar L. Ramos, Joana O. Pereira, Sara I. Silva, Maria M. Amorim, João C. Fernandes, José A. Lopes-da-Silva, Manuela E. Pintado, F. Xavier Malcata, Food Research International 48 (2012) 681–689

B3234 – Production of yeast chitin–glucan complex from biodiesel industry byproduct

Crude glycerol from the biodiesel industry was used as carbon source for high cell density fed-batch cultivation of Pichia pastoris aiming at producing a chitin–glucan complex (CGC). More than 100 g L?1 biomass was obtained in less than 48 h. The yield of biomass on a glycerol basis was 0.55 g g?1 during the batch phase and 0.63 g g?1 during the fed-batch phase. The chitin–glucan complex was recovered from the yeast cell wall by hot alkaline extraction. CGC content in the cell wall was found to be relatively constant throughout the cultivation (18–26%) with a volumetric productivity of 1.28 g L?1 h?1 at the end of the fed-batch phase. The molar ratio of chitin:?-glucan in the extracted biopolymer was 16:84, close to other CGC extracted from Aspergillus biomass. The extracted polymer was characterized by Differential Scanning Calorimetry (DCS) and solid-state Nuclear Magnetic Resonance (NMR) spectroscopy and compared with commercial biopolymers, namely, crab shell chitin and/or chitosan, algal ?-glucan (laminarin) and fungal chitin–glucan complex (kiOsmetine).
Christophe Roca, Bárbara Chagas, Inês Farinha, Filomena Freitas, Luís Mafrab, Filipe Aguiarc, Rui Oliveira, Maria A.M. Reis, Process Biochemistry 47 (2012) 1670–1675

B3223 – Food protein aggregates as vitamin-matrix carriers: Impact of processing conditions

We studied the ability of protein aggregates for loading and protection of ?-tocopherol, a model of heat-and light-sensitive bioactive compounds. Aqueous dispersions of whey proteins (4.5 wt.%, pH 6.7) in the absence and presence of ?-tocopherol (4 wt.%) were prepared using an ultradisperser (10,000 rpm for 10 min and 65 °C), and then submitted to further high-pressure homogenisation (HPH) at 300 or 1200 bar for 12 cycles. Relative to free-vitamin dispersions, increasing HPH conditions in the presence of vitamin led to higher protein denaturation, more tryptophan quenching and wavelength blue-shift (by 10 nm), in parallel with increased zeta potential values (by -10 mV), particle sizes (by 50%), and newly formed protein dimers, trimers and high molecular weight aggregates. As a result, the degree of vitamin degradation under increasing HPH and long-term storage was shown to decrease from 66% (ultradisper) to 50%, or to 30% (subject to further treatments at 300 or 1200 bar, respectively).
Perla Relkin, Rizwan Shukat, Food Chemistry 134 (2012) 2141–2148

B3233 – Phase diagram of the TbBr3–CsBr binary system. Thermodynamic and transport properties of the Cs3TbBr6 compound

Phase equilibria in the TbBr3–CsBr binary system were established from Differential Scanning Calorimetry (DSC) measurements. This binary system is characterized by three compounds, namely Cs3TbBr6, Cs3Tb2Br9 and CsTb2Br7, and two eutectics located at the TbBr3 mole fraction, x=0.095 (865 K) and x=0.552 (808 K), respectively. Cs3TbBr6 undergoes a solid–solid phase transition at 728 K and melts congruently at 1083 K with the related enthalpies 8.4 and 60.6 kJ mol?1, respectively. Cs3Tb2Br9, decomposes peritectically at 879 K, whereas CsTb2Br9 forms from Cs3Tb2Br9 and TbBr3 at 776 K and melts incongruently at 846 K. It undergoes also a solid–solid phase transition at 805 K, temperature very close to that (808 K) of the Cs3Tb2Br9–CsTb2Br7 eutectic. Separate investigations of the thermodynamic and transport properties were performed on the Cs3TbBr6 compound. These heat capacity and electrical conductivity experimental results suggest an order–disorder mechanism in the alkali metal cation sublattice whereas the TbBr6 octahedra, forming the anionic sublattice, retain their normal lattice positions. Compatibility of the experimental data was tested by the CALPHAD method. The entropy of mixing and Gibbs energies of formation of solid compounds were calculated. The temperature range of Cs3TbBr6 existence was discussed.
Leszek Rycerz, Ida Chojnacka, Jan Kapala, Marcelle Gaune-Escard, CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 37 (2012) 108–115

B3243 – Structural and physico-chemical characterization of some soda lime zinc alumino-silicate glasses

The physico-chemical characterization of the 15Na2O-20CaO-5Al2O3-(60-x)SiO2-xZnO glasses (where x stands for 0, 4, 7 and 10 wt.%), designed as Z(0/ 4 / 7/ 10) and obtained by quenching method, has been carried out by DSC measurements, leaching tests and electrical conductivity measurements in the corresponding melts. Fitted multi-component DSC exotherms of crystallization are discussed in terms of the structural modifications derived from the X-ray measurements and room temperature Raman spectra. Combeite, Na2Ca2Si3O9, was identified as the low-temperature phase crystallized in all glasses under discussion while wollastonite (CaSiO3) was separated as main crystalline phase from the Z4, Z7 and Z10 glasses treated at 800 °C for 20 h. Zn-containing compounds, gahnite (ZnAl2O4) and Ca1.94Zn0.43Al1.25Si1.38O7, were crystallized at 924 °C for a 20 h span in the Z10 glass. The lowest Q3 population, 44.18%, responsible for network connectivity is derived by fitting the Raman spectrum of the Z10 glass. According to the unequal behavior of the Z10 glass as regarding leaching data as well as electrical conductivity measurements of the corresponding melts, the 7% ZnO represents the threshold from where higher degree of network depolymerization and presence of both four- and six-folded zinc atoms are met in these glasses.
S. Petrescu, M. Constantinescu, E.M. Anghel, I. Atkinson, M. Olteanu, M. Zaharescu, Journal of Non-Crystalline Solids 358 (2012) 3280–3288

B3242 – Maps of Fe–Al phases formation kinetics parameters during isothermal sintering

The influence of technological parameters (compaction pressure and sintering temperature) on Fe–Al phase formation was investigated. The kinetics of phase transformation preceding and during an SHS reaction was studied in isothermal conditions by DSC using the JMA (Johnson–Mehl–Avrami) model. This model allowed us to determine basic kinetic parameters, including the Avrami exponent, which characterises the rate and manner of particular phase nucleation. The activation energy (Ea) of particular phase formation was determined by the Kissinger method. XRD analysis and SEM observations of sintered material showed that not only Fe2Al5 phase and low-aluminium solid solution in iron but also aluminium-rich FeAl2 and FeAl3 phases are formed during the sintering of an FeAl50 elementary powder mixture in isothermal conditions with an SHS reaction. The above conclusions were confirmed by iron-based solid solution lattice parameter studies and microhardness measurements
Ewelina Pochec, Stanis?aw Józwiak, Krzysztof Karczewski, Zbigniew Bojar, Thermochimica Acta 545 (2012) 14– 19

B3241 – Combined ab initio, experimental, and CALPHAD approach for an improved thermodynamic evaluation of the Mg–Si system

A new thermodynamic evaluation of the well-known Mg–Si system is presented with the aim to resolve persistent uncertainties in the Gibbs energy of its only compound, Mg2Si. For this purpose the heat capacity and enthalpy of melting of Mg2Si were measured by differential scanning calorimetry. Using finite temperature density functional theory and the quasiharmonic approximation, thermodynamic properties of Mg2Si were additionally calculated up to and above its melting temperature. Using these new data, in particular the heat capacity, the Mg–Si system was evaluated thermodynamically with the CALPHAD method leading to a thermodynamic description of the system within narrow bounds. In contrast to several previous evaluations there is no problem with an inverted miscibility gap in the liquid. Although present enthalpy of melting data turned out to be inconsistent with other data in this system, the new evaluation accurately describes all other available data in this system. In particular the Gibbs energy of Mg2Si can now be considered reliably described.
Michael Schick, Bengt Hallstedt, Albert Glensk, Blazej Grabowski, Tilmann Hickel, Milan Hampl, Joachim Gröbner, Jörg Neugebauer, Rainer Schmid-Fetzer, CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 37 (2012) 77–86

B3251 – Chemical deactivation by phosphorous under lean hydrothermal conditions over Cu/BEA NH3-SCR catalysts

To obtain a better understanding of the deactivation of SCR catalysts that may be encountered due to the presence of P-containing impurities in diesel exhausts, the effects induced by P over Cu/BEA NH3-SCR catalysts were studied as functions of the temperature of poisoning and P concentration in the feed. Cu/BEA catalysts with different Cu loadings (4 and 1.3 wt% Cu) were exposed to P by controlled evaporation of H3PO4 in the presence of 8% O2 and 5% H2O at 573 and 773 K. The reaction studies were performed by NH3-storage/TPD, NH3/NO oxidation and standard NH3-SCR. In addition, a combination of several characterisation techniques (ICP–AES, BET surface area, pore size distribution, H2-TPR and XPS) was applied to provide useful information regarding the mechanism of P deactivation. Pore condensation of H3PO4 in combination with pore blocking was observed. However, the measured overall deactivation was found to occur mostly by chemical deactivation reducing the number of the active Cu species and hence deteriorating the redox properties of the Cu/BEA catalysts. The process of P accumulation on the surface preferentially occurs on the “over exchanged” Cu active sites with the formation of phosphate species. This is likely the reason for the more severe deactivation of the 4% Cu/BEA compared to 1.3% Cu/BEA. Further, the higher NOx reduction performance at 773 K of the P-poisoned Cu/BEA catalysts was found to originate from the lower selectivity towards NH3 oxidation, which occurs predominately on the “over-exchanged” sites.
Stanislava Andonova, Evgeny Vovk, Jonas Sjöblom, Emrah Ozensoy, Louise Olsson, Applied Catalysis B: Environmental 147 (2014) 251– 263

B3240 – Freeze-drying of nanostructure lipid carriers by different carbohydrate polymers used as cryoprotectants

Freeze-drying technique preserves the stability of nanoparticles. The objective of this study was optimization of freeze-drying condition of nano lipid carriers (NLCs). NLCs were prepared by emulsion-solvent evaporation followed by ultra-sonication method. Different carbohydrate and polymeric cryoprotectants including Microcelac® (mixture of lactose and Avicel), Avicel PH102 (microcrystalline cellulose), mannitol, sucrose, Avicel RC591 (mixture of microcrystalline cellulose and sodium carboxymethyl cellulose), maltodextrine, Aerosil and PEG4000 were tested initially. The NLCs showing lower particle size growth and greater absolute zeta potential after freeze drying were chosen for further investigation using Taguchi optimization method. Studied factors included cryoprotectant type and concentration, freezing temperatures applied at different time periods and sublimation time. Sucrose, Avicel RC591 and Aerosil were selected as cryoprotectants from initial screening tests. Increasing their concentration increased the particle size. 1% of Avicel RC591, 24 h of freezing at ?70 °C and 48 h sublimation time showed lower growth in particle size.
Jaleh Varshosaz, Sharareh Eskandari, Majid Tabbakhian, Carbohydrate Polymers 88 (2012) 1157– 1163

B3250 – Crystallisation mechanism of a multicomponent lithium alumino-silicate glass

A base glass of composition 3.5 Li2O?0.15 Na2O?0.2 K2O?1.15 MgO?0.8 BaO?1.5 ZnO?20 Al2O3?67.2 SiO2?2.6 TiO2?1.7 ZrO2?1.2 As2O3 (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi2O6 with nanoscaled crystals forms at 750 °C. Quantitative Rietveld refinement of samples annealed at 750 °C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, ?-eucryptite-like structure (2 × 2 × 2 cell) with Li ordered in the structural channels. The Avrami parameter (n ? 4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 ± 20 kJ mol?1.
R. Wurth, M.J. Pascual, G.C. Mather, A. Pablos-Martín, F. Muñoz, A. Durán, G.J. Cuello, C. Rüssel, Materials Chemistry and Physics 134 (2012) 1001e1006

B3239 – Influence of corona poling on the electrostrictive behavior of cellular polypropylene films

In this study, a quadratic electric field dependence of the strain on the ?30 kV corona-charged cellular polypropylene (PP) was observed, which was found to mainly originate from electrostriction after evaluation of Maxwell stress effect. The ?30 kV-charged sample presented a maximal strain twice as high as that of the non-charged sample for the same applied electric field. Both the dielectric constant and apparent electrostrictive coefficient of cellular PP were also seen to increase after corona poling treatment. We investigated such higher electrostrictive response from the behavior of surface potential decay, the TSC current and the thermal properties. From TSC current curves, it was found that a certain amount of charges became injected into the film. And then, the total charge within the PP was calculated by integrating the TSC current, which provided a convincing evidence for enhanced electrostriction of studied polymer. In addition, from DSC analysis, it was demonstrated that the corona treatment increased the crystallinity of the cellular PP, which was also highly desirable for enhancing the electrostrictive response. Increase in the permittivity and strain was explained experimentally and mathematically by using the space-charge theory and a simplified model.
J.W. Zhang, L. Lebrun, B. Guiffard, P.-J. Cottinet, R. Belouadah, D. Guyomar, L. Garbuio, Sensors and Actuators A 175 (2012) 87– 93

B3249 – Anatase phase formation kinetics in Ti and TiOx nanoparticles produced by gas-phase condensation

Anatase TiO2 nanoparticles were successfully synthesized by post-heat treatments of partially crystalline Ti and amorphous TiOx nanoparticles, respectively produced by inert gas condensation and subsequent oxidation. The nanoparticles condensed on a liquid-nitrogen containing cooling finger (sample LN) were identified to be partially crystalline Ti phase with ~ 10–20 vol.% amorphous TiOx. On the other hand, those condensed on a room-temperature cooling finger (sample RT) were almost completely amorphous TiOx phase. Differential scanning calorimetry scan curves of as-oxidized samples were interpreted using Kissinger analysis, the non-isothermal kinetics, and activation energy for the anatase formation was determined as ~ 455 and 865 kJ/mol for samples LN and RT, respectively. As-oxidized samples LN and RT were heat treated at 400 °C for 2 h, respectively (samples LN-H and RT-H). Samples LN-H and RT-H showed the onset of UV–visible light absorption near 400 nm and the optical band gap of 3.12 and 3.21 eV, respectively, corresponding to anatase. The sample LN-H showed faster photocatalytic decomposition of methylene blue and rhodamine B dyes compared to the sample RT-H due to high crystallinity of anatase and rutile phases.
Yun-Mo Sung, Jun-Su Park, Tae Geun Kim, Journal of Non-Crystalline Solids 358 (2012) 182–187

B3238 – Effects of copper nanowires on the properties of an organic phase change material

The effects of copper nanowires (Cu NWs) with ultra-high aspect ratio and sponge-like structure on the properties of an organic phase change material (PCM) were investigated. Tetradecanol (TD) was selected as the organic PCM. The sponge-like Cu NWs clusters were randomly dispersed in the TD matrix and were wrapped by TD to form a new kind of composite PCM. The phase change enthalpy (?H) of the composite PCMs was decreased linearly with the increasing of Cu NWs loading, while the melting speed was accelerated. The thermal conductivity of the composite PCMs was greatly enhanced by Cu NWs. The ?H of the composite PCM containing 58.9 wt% (corresponding to 11.9 vol%) of Cu NWs was 86.95 J/g, and the thermal conductivity attained to 2.86 W/m K, which was nearly 9 times higher than that of the TD. The thermal conductivity enhancement of Cu NWs on the composite PCMs showed a turning point at the Cu NWs loading of 1.5 vol%. When Cu NWs loading exceeded 1.5 vol%, the thermal conductivity of the composite PCMs increased significantly faster with the increasing of Cu NWs loading.
Ju-Lan Zeng, Fu-RongZhu, Sai-BoYu, LingZhu, ZhongCao, Li-XianSun, Guang-RongDeng, Wen-Pei Yan, LingZhang, Solar Energy Materials & Solar Cells 105 (2012) 174–178

B3248 – Diffusion mechanism of Zr-based metallic glass during oxidation under dry air

Oxidation kinetics of a Zr55Cu30Al10Ni5 bulk metallic glass (BMG) and its crystalline counterpart were studied under dry artificial air at 673 K for long oxidation duration by thermogravimetry analysis (TGA). Oxidation kinetics was observed to follow a parabolic-rate law for the crystalline counterpart and a three-stage behaviour for the BMG. The ionic diffusion mechanism was investigated by using a two-stage oxidation treatment (16O2 oxidation and then 18O2 oxidation). The evident solute penetration zone and ion diffusion characteristic through the oxide scale were determined by Cs+ secondary ion mass spectrometry (SIMS) depth profile. The results of ion evolution indicated that the oxide grew under concurrent inward oxygen and outward Zr diffusions in short-term stage of the BMG oxidation; and the oxidation kinetics was controlled mainly by outward Cu and inward O diffusions in the case of long-term oxidation process.
B. Wang, D.Y. Huang, N. Prud’homme, Z. Chen, F. Jomard, T. Zhang, V. Ji, Intermetallics 28 (2012) 102-107

B3237 – Spark plasma sintering synthesis of Ni1?xZnxFe2O4 ferrites: Mössbauer and catalytic study

Nickel-zinc ferrite nanoparticles, Ni1 xZnxFe2O4 (x ¼ 0, 0.2, 0.5, 0.8, 1.0) were prepared by combination of chemical precipitation and spark plasma sintering (SPS) techniques and conventional thermal treatment of the obtained precursors. The phase composition and structural properties of the obtained materials were investigated by X-ray diffraction and Mössbauer spectroscopy and their catalytic activity in methanol decomposition was tested. A strong effect of reaction medium leading to the transformation of ferrites to a complex mixture of different iron containing phases was detected. A tendency of formation of Fe-carbide was found for the samples synthesized by SPS, while predominantly iron-nickel alloys ware registered in TS obtained samples. The catalytic activity and selectivity in methanol decomposition to CO and methane depended on the current phase composition of the obtained ferrites, which was formed by the influence of the reaction medium.
Nikolay Velinov, Elina Manova, Tanya Tsoncheva, Claude Estournès, Daniela Paneva, Krassimir Tenchev, Vilma Petkova, Kremena Koleva, Boris Kunev, Ivan Mitov, Solid State Sciences 14 (2012) 1092-1099

B3247 – K3YB6O12: A new nonlinear optical crystal with a short UV cutoff edge

A new non-centrosymmetric borate, K3YB6O12, has been synthesized by solid state reaction techniques, and a K3YB6O12 crystal with dimensions of ?40 mm × 30 mm × 10 mm was successfully grown by the top-seeded solution growth method using a K2O–B2O3–KBF4 flux. K3YB6O12 crystallizes in the trigonal space group R32 with cell parameters of a = 13.2202(19) Å, c = 30.281(6) Å, and Z = 15. In the structure of K3YB6O12, B5O10 groups are bridged by Y3O12 chains and discrete YO6 octahedra via corner-sharing, constructing columns packed side by side in a hexagonal motif along the c-axis to form a three-dimensional framework. The three-dimensional framework affords one-dimensional tunnels of 8-membered rings along the b-axis which are occupied by K atoms. K3YB6O12 melts incongruently at 941 °C, and exhibits a short UV cutoff edge at 195 nm. The second harmonic generation effect of K3YB6O12 is weaker than that of KH2PO4
Sangen Zhao, Guochun Zhang, Jiyong Yao, Yicheng Wu, Materials Research Bulletin 47 (2012) 3810–3813

B3236 – Physicochemical properties and inhibition effect on iron deficiency anemia of a novel polysaccharide-iron complex (LPPC)

Porphyran (P) was extracted from red algae Porphyra by boiling water. A novel polysaccharide-iron complex (LPPC) was prepared under the alkaline condition by adding a ferric chloride solution to the low molecular weight porphyran (LP) solution. Physicochemical properties and inhibition effect on iron deficiency anemia of this complex were studied. The content of iron(III) in the complex is 21.57% determined with iodometry. The results indicate that LPPC was product required. The complex can increase red blood cell count (RBC), hemoglobin (Hb), Serum iron (SI), spleen index, spleen mass and mass of mice with iron deficiency anemia (IDA). Although the structure and deeper mechanisms on hemolytic anemia of LPPC should be further studied, LPPC is hoped to be developed as a late-model iron supplement which has a synergism on anemia.
Zhong-Shan Zhang, Xiao-Mei Wang, Zhi-Ping Han, Li Yin, Ming-Xing Zhao, Shu-Chi Yu, Bioorganic & Medicinal Chemistry Letters 22 (2012) 489–492

B3246 – Influence of residual stresses and grain size on the spinodal decomposition of metastable Ti1?xAlxN coatings

At elevated temperatures, the metastable Ti1 ? xAlxN solid solution decomposes in cubic AlN and cubic TiN. Within this work, the effect of residual stresses on the decomposition of sputtered Ti1 ? xAlxN coatings was investigated. Using different bias voltages, a series of Ti1 ? xAlxN coatings (x = 0.63) with stresses ranging from + 630 to ? 2500 MPa was synthesized on Si (100) substrates. Vacuum annealing treatments and subsequent X-ray diffraction measurements showed that tensile stresses foster the formation of more volume consuming cubic TiN domains, while compressive stresses promote the formation of smaller cubic AlN domains. The influence of the grain size has been considered by investigations of free standing films using differential scanning calorimetry. Smaller grains lead to faster decomposition and earlier precipitation of wurtzite AlN.
N. Schalk, C. Mitterer, J. Keckes, M. Penoy, C. Michotte, Surface & Coatings Technology 209 (2012) 190–196

B3245 – Preparation, structure, and photoluminescence properties of new layered borates KBaRE(B3O6)2 (RE ¼ Y, Eu, and Tb)

A series of potassium barium rare earth borates, KBaRE(B3O6)2 (RE = Y, Eu, and Tb), have been synthesized with solid state reaction techniques. Single crystals of the first member of the series, KBaY(B3O6)2, have been grown via spontaneous crystallization. Single crystal X-ray diffraction results show that KBaY(B3O6)2 belongs to the trigonal system, space group R with cell parameters of a = 7.1677(10) Å, c = 17.588(4) Å, and Z = 3. The nearly planar B3O6 groups serve as the fundamental building units, which are distributed layer upon layer along the c axis. Regular YO6 octahedra and irregular Ba/KO9 polyhedra alternately locate between the B3O6 layers and form YO6 and Ba/KO9 polyhedra layers, respectively. DSC analysis shows that the melting point of KBaY(B3O6)2 is 989 °C, and the X-ray powder diffraction pattern of melted KBaY(B3O6)2 crystal confirms that it melts incongruently. The photoluminescence properties of KBaEu(B3O6)2 and KBaTb(B3O6)2 under UV excitation have also been investigated.
Sangen Zhao, Jiyong Yao, Erpan Zhang, Guochun Zhang, Jianxiu Zhang, Peizhen Fu, Yicheng Wu, Solid State Sciences 14 (2012) 305-310

B3244 – Nucleation and crystallisation kinetics of a Na-fluorrichterite based glass by differential scanning calorimetry (DSC)

The present paper shows the results of a nucleation and crystallisation study of a Na-fluorrichterite glass carried out by dynamic scanning calorimetry (DSC). The kinetic study was performed using different procedures (Kissinger, Matusita–Sakka and Kissinger–Akahira–Sunose (KAS) methods), and the Avrami parameter was determined from the Ozawa and Malek approximations and the Malek equation. The results have indicated the coexistence of surface and bulk crystallisation in the devitrification process of the studied glass. The kinetic study has shown that the activation energy of the crystallisation process is over 400 kJ/mol and that the mechanism proposed is a Johnson–Mehl–Avrami mechanism with n equal to 3, which implies that the crystallisation develops through the three-dimensional growth of crystals. The study of the variation of the activation energy with crystallisation using the KAS method has shown that the crystallisation process undergoes a multiple step mechanism, where the main part of the whole process corresponds to the three-dimensional growth of crystals. The mechanism proposed was confirmed by applying the Pérez-Maqueda et al. criterion.
J.M. Pérez, R. Casasola, J.Ma. Rincón, M. Romero, Journal of Non-Crystalline Solids 358 (2012) 2741–2748

B3253 – The effect of surface acidic and basic properties on the hydrogenation of aromatic rings over the supported nickel catalysts

Ni/Al2O3, Ni/MgAlO and Ni/MgO catalysts containing about 60 wt% of nickel were prepared by the co-precipitation method. The textural and structural properties were characterized and it was found that the dispersion of nickel was high in these catalysts. The active nickel surface area was found to be high (78 m2/gcat.) in Ni/MgAlO, corresponding to the average nickel particle size of 3.5 nm. Microcalorimetric adsorption of NH3 and CO2 showed that the Ni/Al2O3 and Ni/MgO exhibited strong surface acidity and basicity, respectively, while the Ni/MgAlO possessed both surface acidity and basicity. In addition, both the initial heat and coverage were higher on Ni/Al2O3 than on Ni/MgO for the adsorption of toluene, indicating the strong interaction between the aromatic rings in toluene (that may act as a Lewis base due to the enriched electron densities) and the surface acidic sites on the support. The adsorption of toluene on the metallic nickel surface produced higher heat, indicating the strong interaction of the ? electrons in aromatic rings of toluene with the d orbitals of surface nickel atoms. Although the adsorption of H2 showed the higher active surface nickel area in Ni/MgAlO than in Ni/Al2O3, the activities of hydrogenation of toluene and phenol were significantly higher on Ni/Al2O3 than on Ni/MgAlO, indicating the important effect of surface acidity on the hydrogenation of aromatic rings.
Shenghua Hu, Mingwei Xue, Hui Chen, Jianyi Shen, Chemical Engineering Journal 162 (2010) 371–379

B3263 – High-pressure phase relations in the system CaAl4Si2O11–NaAl3Si3O11 with implication for Na-rich CAS phase in shocked Martian meteorites

High-pressure phase relations in the system NaAl3Si3O11–CaAl4Si2O11 were examined at 13–23 GPa and 1600–1900 °C, using a multianvil apparatus. A Ca-aluminosilicate with CaAl4Si2O11 composition, designated CAS phase, is stable above about 13 GPa at 1600 °C. In the system NaAl3Si3O11–CaAl4Si2O11, the CAS phase dissolving NaAl3Si3O11 component coexists with jadeite, corundum and stishovite below 22 GPa, above which the CAS phase coexists with Na-rich calcium ferrite, corundum and stishovite. At 1600 °C, the solubility of NaAl3Si3O11 component in the CAS solid solution increases with increasing pressure up to about 50 mol% at about 22 GPa, above which the solubility decreases with pressure. The maximum solubility of NaAl3Si3O11 component in the CAS phase increases with temperature up to around 70 mol% at 1900 °C at 22 GPa. The dissociation of NaAlSi2O6 jadeite to NaAlSiO4 calcium ferrite plus stishovite occurs at about 22 GPa. Lattice parameters of the CAS phase with the hexagonal Ba-ferrite structure change with increase of the NaAl3Si3O11 component: a-axis decreases and c-axis slightly increases, resulting in decrease of molar volume. Enthalpies of the CAS solid solutions were measured by high-temperature drop-solution calorimetry techniques. The results show that enthalpy of hypothetical NaAl3Si3O11 CAS phase is much higher than the mixture of NaAlSi2O6 jadeite, corundum and stishovite and is close to that of the mixture of NaAlSiO4 calcium ferrite, corundum and stishovite. When we adopt the Na:Ca ratio of 75:25 of the natural Na-rich CAS phase in a shocked Martian meteorite, Zagami, the phase relations determined above suggest that the natural CAS phase crystallized from melt at pressure around 22 GPa and temperature close to or higher than 2000–2200 °C. The inferred P, T conditions are consistent with those estimated using other high-pressure minerals in the shocked meteorite.
M. Akaogi, M. Haraguchi, K. Nakanishi, H. Ajiro, H. Kojitani, Earth and Planetary Science Letters 289 (2010) 503–508

B3252 – Mechanistic investigation of hydrothermal aging of Cu-Beta for ammonia SCR

The selective catalytic reduction of NOx with NH3 over a Cu-BEA catalyst was studied after hydrothermal aging between 500 and 900 °C. The corresponding catalyst was characterized using XPS and XRD techniques in the aging interval of 500, 700 and 800 °C. No structural changes during the aging process were observed. However, the oxidation state of copper changed during aging and more Cu2+ was formed. We suggest that one of the deactivation mechanisms is the decrease of the Cu+ species. The NO oxidation and NH3 oxidation activity was decreased with increasing aging temperature. Further, we observed that the ammonia oxidation was decreased faster compared to the SCR reactions at low aging temperatures. The experiments from the calorimeter as well as from the ammonia TPD investigations indicate a trend towards more weakly bound ammonia with higher aging temperatures. From the results of the SCR experiments using different NO2/NOx ratios and ammonia oxidation experiments we suggest that most of the N2O is coming from side reactions of the SCR mechanism and not from reactions between NH3 and O2 alone. Interestingly, we observe that after the 900 °C aging a quite large activity remained for the case with 75% NO2/NOx ratio. The N2O production shows a maximum at 200 °C, but increases again at higher temperatures. However, the N2O formed at low temperature is decreased after hydrothermal aging while the high temperature N2O is increased. We propose that the different reactions examined in this work do not all occur on the same type of sites, since we observe different aging trends for some of the reactions.
Norman Wilken , Kurnia Wijayanti , Krishna Kamasamudram , Neal W. Currier , Ramya Vedaiyan, Aleksey Yezerets, Louise Olsson, Applied Catalysis B: Environmental 111– 112 (2012) 58– 66

B3262 – Determination of the thermodynamic stability of TiB2

The standard free energy of formation of titanium boride (TiB2) was measured by the Electro Motive Force (EMF) method (by using yttria doped thoria (YDT) as the solid electrolyte). Two galvanic cells viz. Cell (I): Pt, TiB2 (s), TiO2 (s), B (s) |YDT| NiO (s), Ni (s), Pt and cell (II): Pt, TiB2 (s), TiO2 (s), B (s) |YDT| FeO (s), Fe (s), Pt were constructed in order to determine the ?fG° of TiB2. Enthalpy increments on TiB2 were measured by using inverse drop calorimetry over the temperature range 583–1769 K. The heat capacity, entropy and the free energy function have been derived from these experimental data in the temperature range 298–1800 K. The mean value of the standard enthalpy of formation of TiB2 ( ?TiB2?) was obtained by combining these ?fG° values and the free energy functions of TiB2 derived from the drop calorimetry data. The mean values of ?TiB2? derived from the ?fG° data obtained from cell I and II were ?322 ± 1.2 kJ mol?1 and ?323.3 ± 2.1 kJ mol?1, respectively. These values were found to be in very good agreement with the assessed data.
Ashish Jain, R. Pankajavalli, S. Anthonysamy, K. Ananthasivan, R. Babu, V. Ganesan, G.S. Gupta, Journal of Alloys and Compounds 491 (2010) 747–752

B3261 – Glass formation in the Nb–Si binary system

Nb81.3Si18.7 ribbons were prepared by rapid quenching of the liquid on a rotating copper wheel using various values of rotating speed. It was found that the melt spun ribbons consisted of an amorphous matrix; however the critical cooling rate for the formation of fully amorphous ribbons was achieved at rather high values of wheel speed. Crystallization occurs upon annealing above 971 K. The Vickers hardness of the amorphous ribbons was found to be 915 HV, an unusually high value for a binary alloy. The atomic structure of the amorphous Nb–Si alloy was studied using real space pair distribution (PDF)/radial distribution functions (RDF) derived from high precision X-ray diffraction data acquired with high-energy, monochromatic synchrotron light in transmission.
K. Georgarakis, Y. Li, M. Aljerf, D. Dudina, A. LeMoulec, A.R. Yavari, G. Vaughan, A. Inoue, Journal of Alloys and Compounds 504S (2010) S14–S17

B3260 – Structural role of Zr4+ as a nucleating agent in a MgO–Al2O3–SiO2 glass-ceramics: A combined XAS and HRTEM approach

The environment around Zr4+ is studied at the Zr K-edge in a MgO–Al2O3–SiO2 glass-ceramics heat treated along its very first crystallization steps. The heat treatments were calibrated by differential scanning calorimetry. ZrO2 acts as a nucleating agent, adding a nucleation/crystallization event around 920 °C, less than 100 °C above the glass transition temperature (830 °C) and below the massive crystallization of the parent-glass (~ 1015 °C). It also lowers crystallization temperatures of the matrix as compared with a Zr-free sample. High-resolution transmission electron microscopy imaging allows an unambiguous attribution to tetragonal ZrO2 for, at least, some of the very first detectable crystallites. Zr K-edge extended X ray absorption fine structure analysis shows a peculiar surrounding around Zr4+ in the parent glass, composed of Si (Mg,Al) and Zr sites linked by edge sharing. This indicates direct linkages between Zr sites, pre-existing in the glass structure that play a key role for promoting nucleation. This analysis is in agreement with only a small part of Zr4+ evolving during the first steps of nucleation toward the formation of few nano-crystals of tetragonal (ZrO2).
Olivier Dargaud, Laurent Cormier, Nicolas Menguy, Laurence Galoisy, Georges Calas, Sophie Papin, Gilles Querel, Luca Olivi, Journal of Non-Crystalline Solids 356 (2010) 2928–2934

B3259 – Dimensional and ice content changes of hardened concrete at different freezing and thawing temperatures

Samples of concrete at different water-to-cement ratios and air contents subjected to freeze/thaw cycles with the lowest temperature at about ?80 °C are investigated. By adopting a novel technique, a scanning calorimeter is used to obtain data from which the ice contents at different freeze temperatures can be calculated. The length change caused by temperature and ice content changes during test is measured by a separate experiment using the same types of freeze–thaw cycles as in the calorimetric tests. In this way it was possible to compare the amount of formed ice at different temperatures and the corresponding measured length changes. The development of cracks in the material structure was indicated by an ultra-sonic technique by measuring on the samples before and after the freeze–thaw tests. Further the air void structure was investigated using a microscopic technique in which air ‘bubble’ size distributions and the so-called spacing factor, indicating the mean distance between air bubbles, were measured. By analyzing the experimental result, it is concluded that damages occur in the temperature range of about ?10 °C to ?55 °C, when the air content is lower than about 4% of the total volume. For a totally water-saturated concrete, damages always occur independently of the use of entrained air or low water-to-cement ratios. It is, further, concluded that the length changes of these samples correspond to the calculated ice contents at different temperatures in a linear fashion.
Björn Johannesson, Cement & Concrete Composites 32 (2010) 73–83

B3258 – Direct determinations of energetic parameters at chitosan/Cr(VI) interfaces by means of immersion heat-conduction microcalorimetry

Interaction parameters at epichlorohydrin-crosslinked chitosan beads/Cr(VI) interfaces from aqueous solutions was obtained by using immersion heat-conduction microcalorimetry. This technique permits simultaneous determinations of adsorbed amounts and interaction energies. The experimental variables evaluated were pH of the Cr(VI) solutions of 4.0 and 6.0, initial Cr(VI) concentration in solution of 0.50 and 5.00 × 10(-3) mol L(-1) and temperature of 25 and 45 °C. The calorimetric results were evaluated using a 2(3) full factorial design. The responses were the adsorption amounts (n(int)), the adsorption energies (Q(int)) and the adsorption enthalpies (?(int)H). The results indicated that all thermodynamic responses (adsorption energies and adsorption enthalpies) are all exothermic in nature. The initial Cr(VI) concentration in solution was the most important parameter in all responses evaluated in this study. Polynomial fits have pointed out that almost all interactive effects are statistically important on the values of n(int), Q(int) and ?(int)H. It is concluded that the thermodynamical aspects of the Cr(VI) adsorption parameters are greatly influenced by the interactive factors and not by temperature changes alone.
Antonio R. Cestari, Eunice F.S. Vieira, Rivaldo C. Silva, Marcos A.S. Andrade Jr., Journal of Colloid and Interface Science 352 (2010) 491–497

B3257 – Cement–epoxy/water interfaces – Energetic, thermodynamic, and kinetic parameters by means of heat-conduction microcalorimetry

Hydration phenomena at cement/water interfaces drive the characteristics of oil-well cement slurries. In this study, new epoxy-modified cement slurries were synthesized. The slurries characterization has suggested the presence of low amounts of portlandite in the slurry with the higher content of polymerized epoxy resin. The hydration processes of the cement slurries were studied by heat-conduction microcalorimetry. The energetic and enthalpic hydration data were all exothermic in nature. The cumulative heat release curves have shown the presence of multilinearity of the kinetic processes. The hydration microcalorimetric data were well fitted to the multistep Avrami kinetic model. It was found that the epoxy-modified cement slurries present a good potential to be used in environmental-friendly oil-well operations.
Antonio R. Cestari, Eunice F.S. Vieira, Andréa M.G. Tavares, Marcos A.S. Andrade Jr., Journal of Colloid and Interface Science 343 (2010) 162–167

B3256 – Analysis of the orientational order effect on n-alkanes: Evidences on experimental response functions and description using Monte Carlo molecular simulation

Short-range correlations of the molecular orientations in liquid n-alkanes have been extensively studied from depolarized Rayleigh scattering and thermodynamic measurements. These correlations between segments induce structural anisotropy in the fluid bulk. This phenomenon, which is characteristic of linear chain molecules when the constituting segments are nor freely jointed, but interact through a given angular potential, is then present in the linear n-Cn series, increasing its magnitude with chain length, and it is therefore less relevant or even completely absent in branched alkanes. This intermolecular effect is clearly revealed in second-order excess magnitudes such as heat capacities when the linear molecule is mixed with one whose structure approaches sphericity. The mixing process of different aspect ratio chain molecules is thought to modify the original pure fluid structure, by producing a diminution of the orientational order previously existing between pure n-alkane chains. However, second-order thermodynamics quantities of pure liquids C(P), ( partial differentialv/ partial differentialT)(P), and ( partial differentialv/ partial differentialP)(P) are known to be very sensitive to the specific interactions occurring at the microscopic level. In other words, the behavior of these derived properties versus temperature and pressure can be regarded as response functions of the complexity of the microscopic interactions. Thus, the purpose of the present work is to rationalize the orientational order evolution with both temperature and molecular chain length from the analysis of pure fluid properties. To this aim, we focused on two linear alkanes, n-octane (n-C(8)) and n-hexadecane (n-C(16)), and two of their branched isomers, i.e., 2,2,4-trimethylpentane (br-C(8)) and 2,2,4,4,6,8,8-heptamethylnonane (br-C(16)). For each compound, we propose a combined study from direct experimental determination of second-order derivative properties and Monte Carlo simulations. We performed density rho, speed of sound c, and isobaric heat capacity C(P) measurements in broad ranges of pressure and temperature allowing a complete thermodynamic characterization of these compounds. Monte Carlo simulations provide a link between the molecular scale model and the experimental thermodynamic properties. Additional information about the microscopic structure of the simulated fluid model was derived, through the calculation of the radius of gyration and average end-to-end distances. Orientational order is clearly revealed by the experimental residual heat capacity trend of pure linear alkanes. The close agreement observed between this experimental macroscopic property and the calculated theoretical structural parameters support the conclusion that the orientational order between segments of linear molecules should be regarded as a conformational effect due to the flexibility of the chain.
D. Bessières, M. M. Piñeiro, G. De Ferron, F. Plantier, The Journal of Chemical Physics 133, 074507 (2010)

B3255 – Flow calorimetry and adsorption study of dibenzothiophene, quinoline and naphthalene over modified Y zeolites

The adsorptive removal of dibenzothiophene (DBT), quinoline and naphthalene in hexadecane on the zeolites, NaY, NiY and CsY, using liquid phase flow calorimetry and adsorption experiments, was studied at 30 °C. NiY and CsY were prepared by the liquid phase ion-exchange method. The adsorbents were characterized by XRD, BET surface area, elemental analysis (ICP-OES) and DRIFT spectroscopic techniques. The adsorption experiments were carried out by equilibrium adsorption and flow calorimetry techniques. Modification of NaY zeolite with Ni and Cs salts resulted in the partial amorphotization of the zeolite structure which affected the adsorption properties. A higher heat of adsorption was determined for quinoline compared to DBT and naphthalene and a preferential adsorption of quinoline in a mixture containing quinoline, naphthalene and DBT was observed on NaY, NiY and CsY. The adsorption of quinoline on NiY possibly involved a direct end-on ? interaction of the Ni2+ with the lone pair of electrons of the N atom on quinoline while the adsorption of DBT and naphthalene occurs via a ? interaction of the d orbitals of Ni2+ with the electrons in the aromatic rings. The equilibrium adsorption capacity of NaY was found to be the highest among the three zeolites. The decrease in the adsorption capacities of NiY and CsY appears to result mainly from the partial collapse of the zeolite structure during the ion-exchange process
J. Keir Thomas, Kamalakar Gunda, Peter Rehbein, Flora T.T. Ng, Applied Catalysis B: Environmental 94 (2010) 225–233

B3254 – Synthesis and characterization of ultramicroporous silica xerogels

Tailoring the porous texture of silica xerogels is of great interest in catalysis, adsorption and sensors. We report the preparation and characterization of xerogels with pore size distribution lower than 0.5 nm, synthesized by hydrolysis and condensation of tetraethylorthosilicate (TEOS) at pH 2.5. N2 (77 K) and CO2 (273 K) adsorption isotherms and immersion calorimetry into liquids with different molecular size (dichloromethane, 0.33 nm; trichloromethane, 0.40 nm; n-hexane, 0.43 nm; cyclohexane, 0.48 nm; isooctane, 0.59 nm; and carbon tetrachloride, 0.66 nm) were used to characterize ultramicroporous xerogels. All the xerogel samples adsorbed CO2 (273 K) but not N2 (77 K). Pore size distributions from immersion calorimetry showed that hydrolysis and condensation of TEOS at pH 2.5 produced silica xerogels with pore size distributions in the 0.33–0.48 nm range. Xerogels synthesized at 333 K and a 5.5:1 water:TEOS molar ratio produced xerogels with higher specific surface areas and wider pore size distributions than xerogels obtained at 293 K and at 2.5:1 water:TEOS molar ratio
Jesús C. Echeverría, Juncal Estella, Vanesa Barbería, Javier Musgo, Julián J. Garrido, Journal of Non-Crystalline Solids 356 (2010) 378–382

B3275 – Equimolar CO2 Absorption by Anion-Functionalized Ionic Liquids

Amino acid ionic liquid trihexyl(tetradecyl)phosphonium methioninate [P66614][Met] and prolinate [P66614][Pro] absorb CO2 in nearly 1:1 stoichiometry, surpassing by up to a factor of 2 the CO2 capture efficiency of previously reported ionic liquid and aqueous amine absorbants for CO2. Room temperature isotherms are obtained by barometric measurements in an accurately calibrated stirred cell, and the product identity is confirmed using in situ IR. Density functional theory (DFT) calculations support the 1:1 reaction stoichiometry and predict reaction enthalpies in good agreement with calorimetric measurements and isotherms
Burcu E. Gurkan, Juan C. de la Fuente, Elaine M. Mindrup, Lindsay E. Ficke, Brett F. Goodrich, Erica A. Price, William F. Schneider, Joan F. Brennecke, J. Am. Chem. Soc. 2010, 132, 2116–2117

B3264 – Energetic effects of ether and ketone functional groups in 9,10-dihydroanthracene compound

The energetic effects caused by replacing one of the methylene groups in the 9,10-dihydroanthracene by ether or ketone functional groups yielding xanthene and anthrone species, respectively, were determined from direct comparison of the standard (p° = 0.1 MPa) molar enthalpies of formation in the gaseous phase, at T = 298.15 K, of these compounds. The experimental static-bomb combustion calorimetry and Calvet microcalorimetry and the computational G3(MP2)//B3LYP method were used to get the standard molar gas-phase enthalpies of formation of xanthene, (41.8 ± 3.5) kJ · mol?1, and anthrone, (31.4 ± 3.2) kJ · mol?1. The enthalpic increments for the substitution of methylene by ether and ketone in the parent polycyclic compound (9,10-dihydroanthracene) are ?(117.9 ± 5.5) kJ · mol?1 and ?(128.3 ± 5.4) kJ · mol?1, respectively.
Vera L.S. Freitas, José R.B. Gomes, Maria D.M.C. Ribeiro da Silva, J. Chem. Thermodynamics 42 (2010) 1248–1254

B3274 – Isotope Effect on Eutectic and Hydrate Melting Temperatures in the Water-THF System

Differential scanning calorimetry was used to study the effect of isotopic substitution on the eutectic and melting temperatures in the water-tetrahydrofuran (THF) system with THF molar fractions near the stoichiometry of the hydrate phase. Deuteration of the host causes an opposite effect from that of the guest with respect to the hydrate liquidus curve and eutectic melting temperature. The eutectic temperature in -containing systems is approximately 3.7?K higher than that in -containing systems. The melting temperatures of THF and deuterated THF hydrates increase by roughly 3.5?K with heavy water. The inclusion of deuterated THF causes a depression of the hydrate liquidus temperatures and a small but measurable effect on the eutectic temperature.
C. Y. Jones, J. S. Zhang, J.W. Lee, Journal of Thermodynamics, Volume 2010, Article ID 583041

B3273 – Monitoring the aggregation behaviour of self-assembling polymers through high-resolution ultrasonic spectroscopy

Poloxamer 407 is a well-known self-assembling polymer with a wide range of temperature- and concentration-dependent phase behaviour, such as micellization and gelation. This work was carried out to demonstrate the potential of high-resolution ultrasonic spectroscopy in evaluating aggregation-deaggregation behaviour of self-assembling polymers. In order to achieve this objective, six different concentrations of Poloxamer 407 water dispersion were prepared and analysed between 5 and 35 degrees C using ultrasonic spectroscopy. For comparison, the same samples were also analysed by the DSC technique. The results showed that polymer aggregation process can be successfully monitored using both ultrasonic parameters of sound speed and attenuation. Furthermore, good agreement with DSC data was observed in terms of characteristic transition temperatures and also in terms of micellization kinetics and related parameters
Marco Cespi, Giulia Bonacucina, Giovanna Mencarelli, Stefania Pucciarelli, Gianfabio Giorgioni, Giovanni F. Palmieri, International Journal of Pharmaceutics 388 (2010) 274–279

B3272 – DNA interaction with flavone and hydroxyflavones

In recent years flavonoids have attracted a great interest as potential therapeutic drugs against a wide range of diseases. While the antioxidant activity of these natural polyphenolic compounds is well known, their binding to DNA characteristics is not fully understood despite the fact that many of them exert their biological effects by reversibly binding to nucleic acids. The present study aims to investigate the interaction of flavone and four hydroxyflavone isomers with double stranded DNA, occurring in bulk solution. A combination of micro-DSC and UV spectroscopy has been used to study the effect of these compounds and of their structure on the structure and stability of the DNA molecule. The characteristics of DNA thermal denaturation have been used as a measure of the effect of the compounds on the stability of the double helix. Micro-DSC has been used to determine the temperature dependence of the heat capacity of the process of thermal denaturation of DNA in solutions containing flavone and the following hydroxyflavones: 3-hydroxyflavone, 5-hydroxyflavone, 6-hydroxyflavone and 7-hydroxyflavone. The observed enthalpy of transition and the transition temperature of DNA thermal denaturation were determined for each compound. UV thermal denaturation curves were also recorded, under the same experimental conditions as the DSC measurements. The transition temperature values and the thermodynamic parameters of thermal denaturation were determined. Differential scanning calorimetry and ultraviolet spectroscopy measurements have evidenced an interaction between the studied flavones and DNA, showing a stabilization of DNA structure, due mainly to intercalation of the flavones. The results also show a noteworthy effect of the structure of the hydroxyflavone isomers on this stabilization.
Joana Vitorino, M.J. Sottomayor, Journal of Molecular Structure 975 (2010) 292–297

B3271 – The effect of compatible solute ectoines on the structural organization of lipid monolayer and bilayer membranes

Compatible solutes are small organic osmolytes responsible for osmotic balance and at the same time compatible with the cellular metabolism. Here, we have investigated the effect of the compatible solutes, ectoine and hydroxyectoine, on the fluid–rigid domain structure of lipid monolayer and bilayer membranes. Mainly saturated dipalmitoyl-phosphatidylcholine membranes exhibiting a clear le/lc phase transition were used. Fluorescence microscopy showed that ectoines added to the aqueous subphase expand and fluidize the lipid monolayers especially at surface pressures below 30 mN/m. The domain structure at the le/lc phase transition is sensitively modified leading to smaller but more numerous domains in the presence of ectoines. Hydroxyectoine was more efficient than ectoine. These results are explained by the replacement theory assuming that the ectoines are likely to be expelled from the membrane surface thus favoring the hydration of the lipid membrane. This effect reduces the line tension, which is the interfacial energy at the domain edges leading to reduced domain sizes and increased number of rigid domains. Isotherms of negatively charged phosphatidylglycerol membranes show a similar expansion, while unsaturated lipids are less affected. Mixed phosphatidylcholine/phosphatidylglycerol membranes exhibit the same effect on the line tension increasing the tendency for a phase separation. This could be shown also in bilayer vesicles, where the compatible solutes have only a minor effect on the lipid main phase transition in pure DPPC membranes but reduce the extent of the pretransition. In mixed DPPC/DPPG bilayer membranes ectoines cause a phase separation leading to the enrichment of expanded DPPC domains. In conclusion, our study gives for the first time evidence that ectoines have an effect on lipid membranes increasing the hydration of the surface and thus increasing the mobility of the lipid head groups and fluidizing the lipid layer accordingly. This increased fluidity may be of advantage for cell membranes to withstand extreme conditions like temperature or osmotic pressure and might also accelerate cellular repair mechanisms.
Rakesh Kumar Harishchandra, Stephanie Wulff, Georg Lentzen, Thorsten Neuhaus, Hans-Joachim Galla, Biophysical Chemistry 150 (2010) 37–46

B3270 – Thermodynamic and structural characterization of Liposomal-Locked in-Dendrimers as drug carriers

A new Liposomal-Locked in-Dendrimer (LLD) formed by DPPC-DPPG and PAMAM 3.5 incorporating the anticancer drug DOX was studied by means of spectroscopic and DSC investigations. Multilamellar Lipid Bilayers were also considered for the sake of comparison. The results were in line with a picture of phase separation between DPPC-DPPG lipids and dendrimer that promotes the stability of the liposome membrane and the cooperativity of the relevant gel-to-liquid-crystal transition, which is enhanced in the presence of the dendrimer and the drug. As a result, the inner core of the liposome contained large amounts of dendrimer-DOX complex and was protected by a very stable membrane. This view was given a more general validation through investigations performed with other types of dendrimers, namely PG1 and PG2. The thermodynamic interpretation of the DSC data allowed a better understanding of the physico-chemical factors that justify this behaviour that makes these LLDs very promising as a new class of Modulatory Liposomal Controlled Release System (MLCRS) that could lead to drug formulations with higher safety and efficacy profiles.
Konstantinos Gardikis, Sophia Hatziantoniou, Marco Signorelli, Marianna Pusceddu, Maria Micha-Screttas, Alberto Schiraldi, Costas Demetzos, Dimitrios Fessas, Colloids and Surfaces B: Biointerfaces 81 (2010) 11–19

B3269 – Influence of protein heat treatment on the continuous production of food foams

The influence of WPI heat treatment on the continuous production of food foams was investigated using a model food including xanthan. The temperature of heat treatment was increased up to 90 °C using a plate heat exchanger; a rotor–stator unit was used for aeration purpose. The aim was to determine the interplay between heat-induced protein denaturation and aggregation, and the process parameters of aeration operation: namely, rotation speed, residence time and operating pressure. Microstructure, texture and stability of 200% overrun foams were analysed. Experimental results demonstrated that foam microstructure, namely overrun and bubble size distribution, was governed by the process parameters of aeration and depended only slightly on thermal treatment. Conversely, foam stability was strongly improved by heat treatment. These trends agreed roughly with results obtained in a batch kitchen mixer, but batch methods remained unable to predict quantitatively the behaviours observed in continuous aeration operation.
I. Nicorescu, C. Vial, C. Loisel, A. Riaublanc, G. Djelveh, G. Cuvelier, J. Legrand, Food Research International 43 (2010) 1585–1593

B3268 – Composition and quality attributes of conventionally and organically farmed Pangasius fillets (Pangasius hypophthalmus) on the German market

A range of conventionally and organically farmed Pangasius or sutchi catfish fillets available on the German market were analysed to compare both composition and quality. Differentiation of Pangasius hypophthalmus from Pangasius bocourti was achieved by RFLP-SSCP analysis. The protein content of conventionally farmed fillets ranged between 13.3 and 15.7%, whereas organically produced fillets had significantly higher protein contents of between 17.0 and 17.4%. No difference in the fat content between farming methods was observed, which varied between 1.4 and 3.2%. Polyunsaturated fatty acids represented about 24% of the total fatty acids with a high level of linoleic acid. The comparison of the proximate composition indicated that water was added to most of the conventionally farmed products, in different amounts, as well as water-binding capacity enhancing additives. Differential scanning calorimetry was used to demonstrate the presence of polyphosphate on muscle proteins. Differences in texture, water-binding capacity and colour are discussed.
Horst Karl, Ines Lehmann, Hartmut Rehbein, Reinhard Schubring, International Journal of Food Science and Technology 2010, 45, 56–66 doi:10.1111/j.1365-2621.2009.02103.x 2010

B3267 – Studies on the conformational change of adsorbed BSA onto a moderately hydrophobic surface at different denaturant concentrations and surface coverages

This paper is aimed at investigating the conformational change of denatured bovine serum albumin (BSA) in combination with thermodynamic functions and their fractions, adsorption isotherms, Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). Microcalorimetric measurements of displacement adsorption enthalpies DeltaH of denatured BSA (by guanidine hydrochloride (GuHCl)) adsorbed onto a moderately hydrophobic surface (PEG-600) from solutions were carried out. The contents of secondary structure elements of BSA in solutions and in the adsorbed state were determined by FTIR and the thermal stability of adsorbed BSA was measured by DSC. The adsorption thermodynamic functions DeltaH, DeltaS, DeltaG, and their fractions were calculated based on the thermodynamics of the stoichiometric displacement theory for adsorption (SDT-A) and adsorption isotherms. The results showed that the surface can provide energy to denatured BSA and make it gain a more ordered conformation with GuHCl concentration increment. At a given GuHCl concentration, although the ordered secondary structure of adsorbed BSA molecules decreased, their tertiary structure may be more perfect with surface coverage increment. The thermodynamic analysis of four subprocesses associated with adsorption also confirmed the increment of conformational gain.
Huan Gao, Xin-Peng Geng, Bao-Huai Wang, Ye Zhou, Journal of Colloid and Interface Science 344 (2010) 468–474

B3266 – Critical behavior of static properties for nitrobenzene-alkane mixtures

We present experimental data of the isobaric heat capacity per unit volume C(p,x)V(-1) for mixtures containing nitrobenzene and an alkane (C(N)H(2N+2), with N ranging from 6 to 15) upon approaching their liquid-liquid critical points along a path of constant composition. Values for the critical amplitude A(+) have been determined. They have been combined with the previously reported ones for the leading term of the coexistence-curve width to obtain, with the aid of well-known universal relations, the critical amplitudes of the correlation length and of the osmotic susceptibility. The trends of all these critical parameters, which exhibit anomalous behavior in the low N region, are discussed in terms of particular microscopic phenomena characterizing NB-C(N)H(2N+2) mixtures. The work is completed with an analysis of the analog of the Yang-Yang anomaly in liquid-liquid criticality: the behavior of the partial molar heat capacities of the two liquid components is found to illustrate previously uncovered asymmetry effects.
Germán Pérez-Sánchez, Patricia Losada-Pérez, Claudio A. Cerdeiriña, Jan Thoen, J. Chem. Phys. 132, 214503 2010

B3265 – Thermal Decomposition and Spectroscopic Studies of Preheated Ammonia Borane

This paper presents enhanced dehydrogenation of solid ammonia borane (AB, NH3BH3) at 85 °C after it was preheated at 80 °C for 2?4 h. Thermal treatments and subsequent hydrogen release experiments were carried out in a Hastelloy cell mounted on a high-pressure differential scanning calorimeter. With increased preheating durations, not only does the induction period for hydrogen release shorten but also the hydrogen release becomes fast. It is deduced that diammoniate of diborane (DADB, [(NH3)2BH2]+[BH4]?), oligomers or polymers, and AB form a solid solution, shifting the melting temperature of AB to a low value. Hydrogen evolution, as the result of the initial stage of oligomerization, is observed after maintaining pristine AB at 80 °C for 20 min. FTIR-ATR spectra of thermally treated AB indicated that only linear dimers of aminoborane (LDAB, NH3BH2NH2BH3) are detected for preheating periods shorter than 3 h, whereas other oligomers and polymers form for the longer thermal treatment at 80 °C.
Junshe Zhang, Yu Zhao, Daniel L. Akins, Jae W. Lee, J. Phys. Chem. C 2010, 114, 19529–19534

B3285 – Model reactions as probe of the acid–base properties of aluminas: Nature and strength of active sites. Correlation with physicochemical characterization

Acetonylacetone conversion at 250 and 350 °C was carried out over various transition aluminas (?- to ?-Al2O3) in order to estimate simultaneously their acid–base properties. The formation of 2,5-dimethylfuran (DMF) was associated to the presence of acid site, and the formation of 2-methyl-3-cyclopenten-1-one (MCP) associated to basic site. First, from carbon dioxide adsorption measurement, hydroxyl basic group was found to be the active site for MCP formation and 2,6-dimethylpyridine (DMP) adsorption measurement shows that Brønsted acid site is active site for DMF formation. Secondly, from catalytic results, we show that ?-Al2O3 possesses a basic/acid ratio (MCP/DMF = 16) higher than the other aluminas (MCP/DMF < 10), and from comparison with cyclopentanol/cyclohexanone mixture transformation (acid alcohol dehydration and acid–base hydrogen transfer between alcohol and ketone), we also show that acetonylacetone cyclization are a more difficult reaction. Finally, the combination of model reactions and CO2 and DMP adsorption allows us to propose a description of the nature and the strength of the various aluminas surface.
Sonia Carre, Benoit Tapin, Ngi Suor Gnep, Renaud Revel, Patrick Magnoux, Applied Catalysis A: General 372 (2010) 26–33

B3284 – Hydrogenation behavior of the solid solutions RE4NiMg1-xAlx and RE4-yNiMg1+y with RE = Gd and Y

The solid solutions RE4NiMg1?xAlx (0 < x < 0.9) and RE4?yNiMg1+y (0 < y < 0.5) with RE = Gd and Y were synthesized from the elements in sealed tantalum ampoules in an induction furnace. The limit of solubility was established in both cases. All the samples crystallize with the cubic Gd4RhIn type structure, space group F-43m. The solubility is much lower in the case of Y than for Gd which is linked with steric effects. The hydrogen sorption is irreversible and the large exothermicity of the reaction can lead to the decomposition of the compounds into rare earth hydrides and metallic Ni and Mg. Nevertheless, it is shown that the Y based compounds can absorb almost 3 wt.% of hydrogen at room temperature and under moderate pressure. Furthermore, the solid solutions do not allow destabilization of the hydrides.
Samuel Couillaud, Stefan Linsinger, Cédric Duée, Aline Rougier, Bernard Chevalier, Rainer Pöttgen, Jean-Louis Bobet, Intermetallics 18 (2010) 1115-1121

B3283 – Hydrogen Storage in Semiclathrate Hydrates of Tetrabutyl Ammonium Chloride and Tetrabutyl Phosphonium Bromide

Original calorimetric and phase equilibrium properties for hydrogen + tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride (TBACl), or tetrabutylphosphonium bromide (TBPB) semiclathrate hydrates were measured using differential scanning calorimetry under pressure. The dissociation temperatures of H2 + TBACI and H2 + TBPB semiclathrate hydrates are very close to the ambient temperature at low pressures around 15.0 MPa. H2 + TBACI and H2 + TBPB systems therefore exhibit better and comparable stability than the H2 + TBAB system at equivalent pressure, respectively. The amount of hydrogen stored in H2 + TBACI and H2 + TBPB semiclathrate hydrates was estimated in terms of the H2-to-water mole ratio (nH2/ nH2O) calculated from disssociation enthalpies and (p, T) equilibrium data. In terms of mass fraction deduced from the ratio (nH2/nH2O), H2 + TBACl and H2 + TBPB semiclathrate hydrates can store 0.12 % and 0.14 % of hydrogen, respectively. Moreover, the quantity of hydrogen stored in these two semiclathrate hydrates is significantly higher than that stored in the H2 + TBAB system
Johnny Deschamps, Didier Dalmazzone, J. Chem. Eng. Data 2010, 55, 3395–3399

B3282 – Glass-Transition Temperatures in CO2 + Polymer Systems: Modeling and Experiment

We extend a previously published compressible lattice model to the prediction of glass-transition temperatures in CO2 + polymer systems. We have applied the model to published data as well as to new measurements of glass-transition temperatures in CO2 + poly(methyl methacrylate) (PMMA) and CO2 + poly(lactic acid) (PLA) systems. We demonstrate that the model is able to predict glass-transition temperatures in CO2 + polymer systems using a parameter that is obtained from sorption data and a second parameter that is obtained from FTIR measurements. The parameters are not dependent on temperature, pressure, or polymer molecular weight.
Anupama Kasturirangan, Carolyn A. Koh, Amyn S. Teja, Ind. Eng. Chem. Res. 2011, 50, 158–162

B3281 – Influence of polymer content on stabilizing milled amorphous salbutamol sulphate

The study investigates the influence of polyvinyl pyrrolidone (PVP) concentration on stabilizing the amorphous form of salbutamol sulphate (SS) before and after storage under ambient and elevated humidity conditions. Different mass ratios of SS and PVP (0-90wt%) were co-milled using a planetary ball mill. X-ray powder diffraction (XRPD), high sensitivity differential scanning calorimetry (HSDSC), dynamic vapor sorption (DVS), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Raman microscopy (RM) were used to analyze the stability of the co-milled mixtures against heat and humidity treatments as well as storage at different humidity conditions. Prior storage, DSC and DVS analyses revealed that re-crystallization of amorphous SS was suppressed above PVP content of 33 wt%. Probable hydrogen bond interaction between SS and PVP was found in FT-IR analysis. XRPD diffractograms and SEM analysis showed stability against re-crystallization was achieved in the co-milled mixtures with a minimum PVP content of 80 wt% after storage. Homogeneous distribution of SS and PVP from RM analysis showed fine clustering of SS and PVP, suggesting the formation of an amorphous dispersion at molecular level. The results provide insights on the application of thermal and humidity treatments, accelerated stability testing and investigations on drug-excipient interactions to predict the minimum ratio of an excipient for stabilizing the amorphous state of a milled API.
P.N. Balani, S.Y. Wong, W.K. Ng, E. Widjaja, R.B.H. Tan, S.Y. Chan, International Journal of Pharmaceutics 391 (2010) 125–136

B3280 – Experimental assessment of heat storage properties and heat transfer characteristics of a phase change material slurry for air conditioning applications

A new microencapsulated phase change material slurry based on microencapsulated Rubitherm RT6 at high concentration (45% w/w) was tested. Some heat storage properties and heat transfer characteristics have been experimentally investigated in order to assess its suitability for the integration into a low temperature heat storage system for solar air conditioning applications. DSC tests were conducted to evaluate the cold storage capacity and phase change temperature range. A phase change interval of approximately 3 °C and a hysteresis behaviour of the enthalpy were identified. An experimental set-up was built in order to quantify the natural convection heat transfer occurring from a vertical helically coiled tube immersed in the phase change material slurry. First, tests were carried out using water in order to obtain natural convection heat transfer correlations. Then a comparison was conducted with the results obtained for the phase change material slurry. It was found that the values of the heat transfer coefficient for the phase change material slurry were higher than for water, under identical temperature conditions inside the phase change interval.
Bogdan M. Diaconu, Szabolcs Varga, Armando C. Oliveira, Applied Energy 87 (2010) 620–628

B3279 – Microcalorimetric study on conformational change of denatured RNase A adsorbed onto a moderately hydrophobic surface

The microcalorimetric method was used to measure the displacement adsorption heat of denatured (by 1.8 mol L?1 guanidine hydrochloride (GuHCl)) Ribonuclease A (RNase A) adsorbed onto a moderately hydrophobic surface (PEG-600) from various ammonium sulfate ((NH4)2SO4) concentration solutions at 298 K. According to the thermodynamics of the stoichiometric displacement theory for adsorption (SDT-A) and the measured adsorption isotherms, the adsorption thermodynamic functions, ?G, ?S, ?H, and their fractions were obtained. In combination with FTIR analysis, the regulation of conformational change of adsorbed denatured RNase A was found. The results showed that the moderately hydrophobic surface can provide energy to denatured protein and make it gain more ordered conformation with (NH4)2SO4 concentration increment. The analysis of thermodynamic fractions showed that the contribution of four subprocesses associated with the displacement adsorption of RNase A was different in various (NH4)2SO4 concentrations.
Yu Chai, Xinpeng Geng, Ailing Liu, Changzheng Zheng, Quan Bai, Colloids and Surfaces A: Physicochem. Eng. Aspects 361 (2010) 1–6

B3278 – Composition and quality of rice flour-fish mince based extruded products with emphasis on thermal properties of rice flour

Extruded products with rice flour and ribbonfish mince mixture were prepared using a twin-screw extruder with varying barrel temperatures, and the quality of the final product was evaluated. The optimum process conditions, as revealed by organoleptic evaluation for acceptable final products, included a barrel temperature of 90C and fish mince concentration of 10%. The amino acid composition of final extruded product revealed a higher content of lysine, glutamic acid and leucine. The increase in expansion ratio and water absorption capacity of extrudate with 10% fish mince was significantly (P < 0.05) influenced by barrel temperature. The breaking strength of the extrudate increased significantly (P < 0.05) with addition of 20% fish mince. The differential scanning calorimetric studies of rice flour indicated the peak value of endothermic transition at 64.73C, which is specific for short grain rice flour. The dynamic rheological testing of rice flour solution (10%) indicated gelatinization temperature at 63.3C.
A.O. Dileep, B.A. Shamasundar, P.K. Binsi, N.K. Howell, Journal of Texture Studies 41 (2010) 190–207

B3277 – A proposed mechanism of tenderising post-rigor beef using high pressure–heat treatment

Tenderness of beef M. Sternomandibularis was tough when cooked from both raw, and when previously heated (60 °C, 20 min), whereas a significant improvement in tenderness was achieved when pressure–heat (P–H) treated muscle (200 MPa, 60 °C, 20 min) was cooked. In order to determine the mechanism for this improvement, connective tissue, myofibrillar and sarcoplasmic proteins, were separated into three fractions and studied with regard to their solubilisation, denaturation and aggregation, degradation and strengthening of protein structures for the three treatments (raw, heated and H–P treated). Measurements included DSC, SDS–PAGE, surface hydrophobicity, and the appearance, length and width of myofibres (light microscopy). For the connective tissue fraction, heat solubility was determined. It is suggested that the mechanism for this improvement in tenderness is the formation of a strengthened myofibrillar structure that, when sheared by mastication, allows the crack to pass through the meat rather than dissipate into a more visco-elastic structure. In this way a more brittle fracture is achieved and the meat is perceived as more tender. The pre-requisite is that adequate enzymatic activity has occurred. It is suggested that cathepsins are responsible.
Anita Sikes, Eva Tornberg, Ron Tume, Meat Science 84 (2010) 390–399

B3287 – An ester derivative of the drug gabapentin: pH dependent crystal stability

Gabapentin solutions with different pHs were prepared and slow crystallization was allowed to occur. Different crystalline forms were obtained at pHs up to 7, whereas alkaline media (pH 9) gave rise to an amorphous product. A new crystal structure of an ethyl ester derivative, obtained at pH 2 under Fischer esterification conditions, is described herein. Esterification blocked the supramolecular interactions typically observed through the carboxyl group of gabapentin, which resulted in a dramatic change in the solid-state structure. As it is known, this change could have a marked influence on the physiological absorption characteristics of the drug, which supports the search for ester-based gabapentin prodrugs as a means of improving the limited bioavailability of the drug.
Vânia André, M. Matilde Marques, M.F. Minas da Piedade, M. Teresa Duarte, Journal of Molecular Structure 973 (2010) 173–179

B3276 – Dialkylimidazolium halide ionic liquids as dual function inhibitors for methane hydrate

Six dialkylimidazolium halide ionic liquids have been investigated for their potential application as novel gas hydrate inhibitors. Their effects on the equilibrium methane hydrate dissociation curve in a pressure range 105–205 bar and the induction time of methane hydrate formation at 114 bar and a high degree of supercooling, i.e., about 25 °C, are measured in a high-pressure micro-differential scanning calorimeter. Similar to dialkylimidazolium tetrafluoroborate investigated in our previous work, these ionic liquids are found to shift the equilibrium hydrate dissociation/stability curve to a lower temperature and, at the same time, retard the hydrate formation by slowing down the hydrate nucleation rate. To understand the performance of these ionic liquids in inhibiting the hydrate formation, the electrical conductivity and infrared spectra of ionic liquids are also obtained and analyzed.
Chongwei Xiao, Nico Wibisono, Hertanto Adidharma, Chemical Engineering Science 65 (2010) 3080–3087

B3286 – Synergistic effect of high pressure processing and Lactobacillus casei antimicrobial activity against pressure resistant Listeria monocytogenes

The purpose of this study was to evaluate combinations of high pressure processing (HPP) and Lactobacillus casei antimicrobial activity against Listeria monocytogenes strains with variation in pressure resistance in culture and in a food model. In culture, combination of HPP (350 MPa, for 1–20 min) and Lb. casei cell extract (CE, 32 CEAU/ml) showed a significant synergistic bactericidal effect (P < 0.05) and the combination treatment decreased pathogen’s population >5 log10 CFU/ml. Synergy between CE and HPP was most evident in the pressure-resistant strain, OSY-8578. Similar result was observed in meat products where high pressure (500 MPa for 1 min), and high-activity CE (100 CEAU/g) caused >5 log reduction in the viability of L. monocytogenes Scott A. The combination treatment resulted in the absence of peaks associated with cellular components in DSC thermogram suggesting that the presence of CE may have caused a considerable damage to cellular components during the high pressure treatment.
Hyun-Jung Chung, Ahmed E. Yousef, New Biotechnology Volume 27, Number 4 September 2010

B3296 – Properties, crystallization mechanism and microstructure of lithium disilicate glass–ceramic

In this study, lithium disilicate glass–ceramic in the TiO2–ZrO2–Li2O–CaO–Al2O3–SiO2 system was investigated for dentistry applications by incorporation of P2O5 and Nb2O5 as nucleation agent. The influence of the particles size (nano and submicron size) and nucleating agents on the crystalline phases, microstructure, crystallization mechanism and mechanical properties were investigated. Our data indicated that in ceramic glass with nano and submicron P2O5, the main crystalline phase was lithium disilicate. The results also showed that change of P2O5 particle’s size had significant effect on the crystalline phases and microstructure. By replacement of submicron P2O5 with submicron Nb2O5, crystallization mechanism was changed from volume to surface crystallization. Due to the nature of crystalline phases as well as the directional crystallization and coarsening, many cracks were observed in the samples containing submicron Nb2O5. The composition of base glass was changed and nano Nb2O5 was added. As a result of these changes, the crystallization mechanism was altered.
P. Goharian, A. Nemati, M. Shabanian c, A. Afshar, Journal of Non-Crystalline Solids 356 (2010) 208–214

B3295 – Analysis of the multistage phase separation reaction in Fe–25 at% Co–9at%Mo

Differential scanning calorimetry (DSC) has been used to characterize the phase reactions during age hardening of a Fe–25 at%Co–9 at%Mo alloy. The heat of reaction which can be accounted for the development of the hardening phase was further analyzed on the basis of the Kissinger method and a fit based on the JMA model. Additionally, the precipitation sequence was studied by in situ small-angle neutron scattering (SANS) as well as in situ X-ray diffraction (XRD) to gain knowledge on the chemistry and crystallography of the prevailing phases. As direct imaging techniques 3D atom probe (3DAP) and high-resolution transmission electron microscopy (HRTEM) were used. The combination of these methods revealed that hardening in the investigated alloy starts with spinodally formed Mo-rich clusters followed by precipitation of the intermetallic m-phase (Fe,Co)7Mo6.
Elisabeth Eidenberger, Michael Schober, Thomas Schmoelzer, Erich Stergar, Peter Staron, Harald Leitner, Helmut Clemens, Phys. Status Solidi A 207, No. 10, 2238–2246 (2010)

B3294 – Characteristics and chemical composition of date palm (Phoenix canariensis) seeds and seed oil

Studies were conducted on properties of seeds and oil extracted from fully ripened Phoenix canariensis date seeds. The percentage composition of the P. canariensis seeds found is: ash 1.18%, oil 10.36%, protein content 5.67%, total carbohydrate 72.59% and moisture 10.20%. The major nutrients (mg/100 g of oil) determined were: potassium (255.43), magnesium (62.78), calcium (48.56) and phosphorus (41.33). The physicochemical properties of the oil observed include: the saponification number 191.28; the iodine number 76.66, the p-anisidine value 3.67; the peroxide value 3.62 meq/kg; the unsaponifiable matter content 1.79%, the free fatty acids content 0.59%; the carotenoid content 5.51 mg/100 g; the chlorophyll content 0.10 mg/100 g and the refractive index 1.45. The main fatty acids of oil were oleic (50.10%), linoleic (19.23%), lauric (10.24%). palmitic (9.83%) and stearic (7.51%). The main triacylglycerols found in P. canariensis seed oil were: LaMM + LaLaP (18.9%), LaMP + MMM (15.31%) and LaOO + PLL + MPL (12.86%). The DSC melting curves revealed that: melting point = 3.71 °C and melting enthalpy = 62.08 J/g. The sterol marker, ?-sitosterol, accounted for 76.06% of the total sterols content in the seed oil followed by campesterol (8.89%) and ?5avenesterol (8.79%). ?-Tocotrienol was the major tocol (66%) with the rest being ?-tocotrienol and ?-tocopherol.
I. Nehdi, S. Omri, M.I. Khalil, S.I. Al-Resayes, Industrial Crops and Products 32 (2010) 360–365

B3293 – Modification of magnetic and magnetocaloric properties of Dy–Co–Al bulk metallic glass introduced by hydrogen

Dy53.8Co17.3Al28.9 bulk metallic glass with a diameter of 3 mm exhibits spin-glass behavior and large coercivity and remanence. Hydrogenation of Dy53.8Co17.3Al28.9 suppresses the magnetic transition temperature and removes coercivity and remanence because of the expansion of average interatomic distance. The advantage of large magnetic entropy changes (17.5 and 9.5 J/kg?K for the field changes from 0 to 50, and from 0 to 20 kOe, respectively) without any hysteresis loss makes Dy53.8Co17.3Al28.9 H170.6 alloy a promising magnetic refrigerant
H. Fu, M. Zou, Niraj K. Singh, Applied Physics Letters 97, 262509 2010

B3292 – Crystal structure, polymorphism, and thermal properties of yttrium borohydride Y(BH4)3

Y(BH4)3 was synthesized by cryo-milling mixtures of LiBH4 and YCl3 and characterized by powder X-ray and neutron diffraction (PXD, PND), differential scanning calorimetry (DSC), and temperature programmed desorption (TPD). The crystal structure was refined in the space group Pa?3 (no. 205) with lattice constant a = 10.8522(7) Å from 11B and D (2H) substituted samples using PND. It was found to contain Y3+ cations in a highly distorted octahedral environment formed by six [BD4]? complex anions. Heat treatment under 10 MPa of deuterium at 475 K led to a phase transformation from the primitive cubic room-temperature phase to a face-centered cubic high-temperature phase with space group Fm?3c (no. 226) and lattice constant a = 11.0086(1) Å. This high-temperature phase shows an ideal and undistorted octahedral coordination around the central Y3+ cation. In situ synchrotron radiation powder X-ray diffraction experiments (SR-PXD) show the presence of an intermediate phase during the thermal decomposition of Y(BH4)3 with presumably orthorhombic symmetry, and lattice constants a = 12.170(14) Å, b = 7.670(5) Å, and c = 7.478 (6) Å, in a narrow temperature region between 473 K and 520 K.
Christoph Frommen, Nadir Aliouane, Stefano Deledda, Jon Erling Fonneløp, Hilde Grove, Klaus Lieutenant, Isabel Llamas-Jansa, Sabrina Sartori, Magnus H. Sørby, Bjørn C. Hauback, Journal of Alloys and Compounds 496 (2010) 710–716

B3291 – Thermodynamic and Transport Properties of the PrBr3-KBr Binary System

Phase equilibrium in the PrBr3?KBr binary system was established from differential scanning calorimetry (DSC). This system exhibits three compounds, K3PrBr6, KPrBr5, and KPr2Br7, and two eutectics located at a mole fraction of PrBr3 (x = 0.182; 849 K and x = 0.552; 753 K), respectively. K3PrBr6 forms at 727 K and melts congruently at 904 K. K2PrBr5 melts incongruently at 847 K, and finally KPr2Br7 forms at 697 K and melts incongruently at 786 K. The electrical conductivity of PrBr3?KBr liquid mixtures was measured down to temperatures below solidification over the whole composition range. Results obtained are discussed in terms of possible complex formation.
Joanna Rejek, Leszek Rycerz, Ewa Ingier-Stocka, Marcelle Gaune-Escard, J. Chem. Eng. Data 2010, 55, 1871–1875 1871

B3290 – In situ studies of structure–reactivity relations in biodiesel synthesis over nanocrystalline MgO

High temperature processing of solvothermally synthesised MgO nanoparticles promotes striking changes in their morphology, and surface chemical and electronic structure. As-prepared NanoMgO comprised ?4 nm cubic periclase nanocrystals, interspersed within an amorphous Mg(OH)(OCH3) matrix. These crystallites appear predominantly (1 0 0) terminated, and the overall material exhibits carbonate and hydroxyl surface functionalities of predominantly weak/moderate base character. Heating promotes gradual crystallisation and growth of the MgO nanoparticles, and concomitant loss of Mg(OH)(OCH3). In situ DRIFTS confirms the residual precursor and surface carbonate begin to decompose above 300 °C, while in situ XPS shows these morphological changes are accompanied by the disappearance of surface hydroxyl/methoxide species and genesis of O? centres which enhance both the surface density and basicity of the resulting stepped and defective MgO nanocrystals. The catalytic performance in tributyrin transesterification with methanol is directly proportional to the density of strong surface base sites.
Janine M. Montero, D. Rob Brown, Pratibha L. Gai, Adam F. Lee, Karen Wilson, Chemical Engineering Journal 161 (2010) 332–339

B3289 – Evolution of water-in-oil emulsions stabilized with solid particles. Influence of added emulsifier

Water-in-oil emulsions made of water droplets dispersed in a continuous paraffin oil phase were prepared and stabilized with hydrophobic silica particles alone. Differential scanning calorimetry (DSC) experiments were carried out to characterize the water droplets freezing transitions and their evolution with time. Water droplet size distribution, oil–water interfacial tension, and rheological stress–strain properties were determined alongside to better understand the role of particles in the formation and stabilization of emulsions. The results obtained were compared to the properties of emulsions prepared with a non-ionic emulsifier, sorbitan monooleate. No interfacial tension reduction was observed at the oil/water interface in presence of particles. As a consequence, the fragmentation of water into droplets required more energy in absence of surface-active emulsifiers. The resulting emulsion droplet size distribution is polydisperse and contains large droplets. Rheology measurements showed that the stability of the emulsion prepared with particles originates from the formation of a 3D network of particles in the continuous oil phase. In emulsion samples containing sorbitan monooleate, calorimetry experiments revealed a progressive displacement of the water droplet freezing transition due to a change in ice nucleation mechanism. The interpretation points out a possible reorganization of the emulsifier film at the water/oil interface, which could modify the conditions of crystallization of dispersed water droplets and affect the emulsion long-term stability. Calorimetry, when used together with other techniques, such as laser light scattering, provides complementary information on the evolution with time of the structure of the emulsion.
Audrey Drelich, François Gomez, Danièle Clausse, Isabelle Pezron, Colloids and Surfaces A: Physicochem. Eng. Aspects 365 (2010) 171–177

B3299 – Structural, thermal and optical characterization of TiO2:ZrO2 thin films prepared by sol–gel method

We have studied the structural and optical properties of thin films of TiO2, doped with 5% ZrO2 and deposited on glass substrate (by the sol–gel method). The dip-coated thin films have been examined at different annealing temperatures (350 to 450 °C) and for various layer thicknesses (63–286 nm). Refractive index and porosity were calculated from the measured transmittance spectrum. The values of the index of refraction are in the range of 1.62–2.29 and the porosity is in the range of 0.21–0.70. The coefficient of transmission varies from 50 to 90%. In the case of the powder of TiO2, doped with 5% ZrO2, and aged for 3 months in ambient temperature, we have noticed the formation of the anatase phase (tetragonal structure with 14.8 nm grains). However, the undoped TiO2 exhibits an amorphous phase. After heat treatments of thin films, titanium oxide starts to crystallize at the annealing temperature 350 °C. The obtained structures are anatase and brookite. The calculated grain size, depending on the annealing temperature and the layer thickness, is in the range (8.58–20.56 nm).
H. Bensouyad, H. Sedrati, H. Dehdouh, M. Brahimi, F. Abbas, H. Akkari, R. Bensaha, Thin Solid Films 519 (2010) 96–100

B3288 – Activation of dihydrogen on supported and unsupported silver catalysts

The activation of dihydrogen on silica, silver, and silica-supported silver (9 wt% Ag) was investigated. Both silica and silver are individually able to dissociate dihydrogen. Silanol groups on silica undergo H ? D exchange at 393 K in D2 as detected by IR spectroscopy. HD is observed in temporal analysis of products (TAP) experiments when H2 and D2 are sequentially pulsed on silver at 673 K; even when the time delay between the isotopes is 4 s, HD is formed, indicating that long-lived surface hydrogen species are present. Differential scanning calorimetry (DSC) shows that the activation of dihydrogen is an activated process: heat signals evoked through H2 pulses on Ag/SiO2 grow with increasing temperature (373–523 K). Nonetheless, the presence of silver on the silica surface accelerates the Si–OH ? Si–OD exchange. Investigation of the exchange kinetics on Ag/SiO2 shows that diffusion processes of the activated hydrogen species are rate determining at higher temperatures (?373 K), when the activation of D2 on silver becomes facile. Indications of diffusion limitation are observed already at 313 K on Pt/SiO2. TAP and DSC measurements show that H2 is more readily activated on silver that has been treated in O2 at 673 K followed by reduction in H2 at 673 K. Morphological changes induced to the silver surfaces or (sub)surface oxygen species are presumed responsible for this effect.
J. Hohmeyer, E.V. Kondratenko, M. Bron, J. Kröhnert, F.C. Jentoft, R. Schlögl, P. Claus, Journal of Catalysis 269 (2010) 5–14

B3298 – Precipitation kinetics of the hardening phase in two 6061 aluminium alloys

The purpose of this work is to study the kinetics of the precipitation of the hardening phase in two Al–Mg–Si alloys. A review of the theoretical framework for solid-state reaction kinetics and the determination of kinetic parameters from DSC curves are provided, then used to quantify ?? precipitation in the two alloys studied. Despite failure to achieve high levels of accuracy, due, in particular, to the dilution of the alloys, the procedure to analyse this precipitation reaction yields valuable results. It is established that ?? precipitates homogenously as needles which grow through an enhanced-diffusion mechanism.
Youcef Aouabdia, Abdelhamid Boubertakh, Smail Hamamda, Materials Letters 64 (2010) 353–356

B3297 – Structural evidence for the nonmonotonic trend of TC in tetragonal PbTiO3ABiScO3 solid solutions

High-T C piezoelectric(1?x)PbTiO 3 ?xBiScO 3 shows a nonmonotonic trend of T C in the tetragonal phase with respect to content of BiScO 3 . To understand this behavior, the structure of (1?x)PbTiO 3 ?xBiScO 3 solid solutions is studied by means of neutronpowderdiffraction. The cation displacements of Pb/Bi and Ti/Sc exhibit a coupling property and a different impact by the substitution content of BiScO 3 . Its nonmonotonic trend of T C is quantitatively related to the calculated spontaneous polarization in the whole tetragonal range. The unique role of Bi-substitution not only contributes to enhance the component of polarization of Pb/Bi but also to increase the T C .
Jun Chen, Krishna Nittala, Jacob L. Jones, Penghao Hu, Xianran Xing, Applied Physics Letters 96, 252908 2010

B3307 – Solid acid catalysts based on H3PW12O40 heteropoly acid: Acid and catalytic properties at a gas–solid interface

Solid acid catalysts prepared by supporting 15 wt%H3PW12O40 heteropoly acid (HPA) on TiO2, ZrO2 and Nb2O5 with a sub-monolayer HPA coverage were characterised at a gas–solid interface, regarding their acid properties and chemical structure of HPA on the catalyst surface and compared to “standard” HPA catalysts such as bulk and silica-supported H3PW12O40 and Cs2.5H0.5PW12O40. In contrast to the parent acid, H3PW12O40, possessing strong Brønsted acid sites, the catalysts supported on TiO2, ZrO2 and Nb2O5 have both Brønsted and Lewis acid sites, with the latter mainly originating from the oxide support. The strength of acid sites in these catalysts is weaker than that in H3PW12O40 and Cs2.5H0.5PW12O40. The catalytic activity (turnover frequency) in gas-phase isopropanol dehydration decreases in the order: H3PW12O40 > Cs2.5H0.5PW12O40 > 15%H3PW12O40/SiO2 > 15%H3PW12O40/TiO2 > 15%H3PW12O40/Nb2O5 > 15%H3PW12O40/ZrO2, which is in line with the acid strength as determined by NH3 adsorption calorimetry. Ammonia adsorption calorimetry, 31P{1H} MAS NMR and FTIR indicate increasing interaction between support and HPA in the following order of supports: SiO2 < TiO2 < Nb2O5 < ZrO2.
Ali M. Alsalme, Paul V. Wiper, Yaroslav Z. Khimyak, Elena F. Kozhevnikova, Ivan V. Kozhevnikov, Journal of Catalysis 276 (2010) 181–189

B3306 – Kinetic Modeling of n-Butane Cracking on HZSM-5 Zeolite Catalyst

A kinetic model of lumps has been established for n-butane cracking over HZSM-5 zeolite catalyst (SiO2/Al2O3 = 30) in the 400?550 °C range, based on the results obtained in a fixed bed reactor (space time, up to 2.4 (g of catalyst) h (mol CH2)?1; He/n-butane molar ratio in the feed, up to 6/1; time on stream, 5 h). The model allows quantifying the distribution of the lumps of products (C2?C4 olefins, C2?C4 paraffins, methane, and C5?C10 components) in a wide range of temperatures, partial pressures of hydrocarbons in the reaction medium, and space times. The kinetic model steps for the transformation of n-butane into olefins and of olefins into paraffins and C5?C10 are second order with respect to the reactant, whereas the remaining steps are first order with respect to each reactant. When the target is the production of C2?C4 olefins, the yield is limited to 12%, at 550 °C.
Diana Mier, Andres T. Aguayo, Monica Gamero, Ana G. Gayubo, Javier Bilbao, Ind. Eng. Chem. Res. 2010, 49, 8415–8423

B3305 – Thermodynamic evaluation of hypereutectic Al–Si (A390) alloy with addition of Mg

This paper presents the thermodynamic evaluation of A390 hypereutectic Al–Si alloy (Al–17% Si–4.5% Cu–0.5% Mg) and alloys up to 10% Mg, using the Factsage® software. Two critical compositions were detected at 4.2% and 7.2% Mg where the temperatures of the liquidus, the start of the binary and of the ternary eutectic reaction are changed. These critical compositions show differences in the formation of Mg2Si intermetallic particles during the solidification interval. For compositions up to 4.2% Mg, the Mg2Si intermetallic phase first appears in the ternary eutectic zone. With Mg contents between 4.2% and 7.2%, Mg2Si particle appears in both the binary and ternary eutectic reactions. Above 7.2% Mg, it solidifies as a primary phase and also during the binary and ternary reactions. The calculated liquid fraction vs. temperature curves also showed a decrease of the eutectic formation temperature (knee point temperature) with the addition of Mg content up to 4.2% Mg. This temperature becomes almost constant up to 10% Mg. The calculation of eutectic formation temperature shows a good agreement with differential scanning calorimetry (DSC) tests.
Alireza Hekmat-Ardakan, Frank Ajersch, Acta Materialia 58 (2010) 3422–3428

B3304 – Thermodynamic investigation of a solid–solid phase change material: 2-Amino-2-methyl-1,3-propanediol by calorimetric methods

An important solid–solid phase change heat storage material (PCM) 2-amino-2-methyl-1,3-propanediol was investigated by calorimetric methods. The molar heat capacities of the compound were measured in the temperature range from 78 to 405 K by means of a small sample automated adiabatic calorimeter. A solid–solid and solid–liquid phase transitions were found at T = 351.598 K and 380.633 K, respectively, from the experimental Cp–T curve. The molar enthalpies and entropies of these transitions were determined to be 24.33 ± 0.02 kJ mol?1, 69.20 ± 0.07 J K?1 mol?1 for the solid–solid phase transition and 4.01 ± 0.01 kJ mol?1, 10.52 ± 0.01 J K?1 mol?1 for the solid–liquid phase transition, respectively. The thermodynamic functions (HT ? H298.15) and (ST ? S298.15), were derived from the heat capacity data in the temperature range of 78–405 K with an interval of 5 K. A precise oxygen-bomb combustion calorimeter was used to obtain the standard molar enthalpy of combustion and the standard molar enthalpy of formation, (C5H11NO2, cr) = (?3326.25 ± 0.52) kJ mol?1 and (C5H11NO2, cr) = (?213.37 ± 0.86) kJ mol?1. DSC and TG tests were performed to investigate the solid–solid and solid–liquid phase transition behaviors and its thermostability. The results were in agreement with those obtained from heat capacity measurements, which indicated that 2-amino-2-methyl-1,3-propanediol possesses typical solid–solid phase change material characteristics, such as, suitable transition temperature, high transition enthalpy and good thermal stability.
Tong Bo, Tan Zhi-Cheng, Liu Rui-Bin, Meng Chang-Gong, Zhang Jing-Nan, Energy Conversion and Management 51 (2010) 1905–1910

B3303 – Hexamethylene dilauroyl, dimyristoyl, and dipalmytoyl amides as phase change materials for thermal energy storage

Hexamethylene dilauroyl, dimyristoyl, and dipalmytoyl amides have been produced as solid–liquid phase change materials via condensation of hexamethylene diamine with the respective acyl chlorides (lauroyl chloride, myristoyl chloride, and palmytoyl chloride) and were characterized by FT-IR, NMR, DSC, and TG analysis. Hexamethylene dilauroyl, dimyristoyl, and dipalmytoyl amides crystallized due to structural symmetry and flexibility of long alkyl groups. They were characterized by DSC and FT-IR spectroscopy before and after thermal cycling to determine their thermal reliability. Phase change enthalpies were found 110.1 and ?103.3 J g?1 for hexamethylene dilauroyl amide (N,N?-hexamethylene didodecanamide), 116.9 and ?110.4 J g?1 for hexamethylene dimyristoyl amide (N,N?-hexamethylene ditetradecanamide), and 144.5 and ?140.5 J g?1 for hexamethylene dipalmytoyl amides (N,N?-hexamethylene dihexadecanamide) by DSC. The endurance of hexamethylene dilauroyl, dimyristoyl, and dipalmytoyl amides was studied by TG analysis.
Gülcin Canik, Cemil Alkan, Solar Energy 84 (2010) 666–672

B3302 – The Binary Phase Diagram of Propranolol Hydrochloride and Crystallization-Based Enantioseparation

Inconsistent results were reported for the solid-state nature of the racemic species of the pharmaceutical relevant compound propranolol hydrochloride. In this work the binary phase diagram of the propranolol hydrochloride enantiomers is studied. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and high performance liquid chromatography (HPLC) were used as analytical methods. The type of the racemic species, the presence and extent of partial solid solutions and the stability regions of polymorphic forms in the system were investigated. The identified binary phase diagram is sketched. Finally, the feasibility of crystallization-based resolution is discussed.
Daniel Polenske, Heike Lorenz, Andreas Seidel-Morgenstern, Journal of Pharmaceutical Sciences, VOL. 99, NO. 4, April 2010

B3312 – Hydration kinetics modeling of the effect of curing temperature and pressure on the heat evolution of oil well cement

The heat evolution of Class G and Class H oil well cements cured under different temperatures (25 °C to 60 °C) and pressures (2 MPa to 45 MPa) was examined by isothermal calorimetry. Curing pressure was found to have a similar effect on cement hydration kinetics as curing temperature. Under isothermal and isobaric conditions, the dependency of cement hydration kinetics on curing temperature and pressure can be modeled by a scale factor which is related to the activation energy and the activation volume of the cement. The estimated apparent activation energy of the different cements at 2 MPa varies from 38.7 kJ/mol to 41.4 kJ/mol for the temperature range of 25 °C to 40 °C, which decreases slightly with increasing curing temperature and pressure. The estimated apparent activation volume of the cements at 25 °C varies from ? 23.1 cm3/mol to ? 25.9 cm3/mol for the pressure range studied here, which also decreases slightly in magnitude with increasing curing temperature.
Xueyu Pang, Walmy Cuello Jimenez, Benjamin J. Iverson, Cement and Concrete Research 54 (2013) 69–76

B3301 – Films of dextran-graft-polybutylmethacrylate to enhance endothelialization of materials

We have synthesized new structures obtained from amphiphilic copolymers of dextran and polybutylmethacrylate with the aim of endothelialization of biomaterials. Grafting of butylmethacrylate onto dextran has been carried out using ceric ammonium nitrate as initiator. Three copolymers were obtained (11, 30 and 37 wt.% dextran) and homogeneous thin films were successfully prepared. In contrast to dextran, the resulting films were stable in water, and copolymers characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry and dynamic mechanical analysis showed evidence of hybrid properties between the parent homopolymers. Surfaces of films were smooth when analyzed by atomic force microscopy (roughness 2+/-1 nm) but greatly differed in their hydrophilicity by increasing the dextran content (water contact angle from 99 degrees to 57 degrees). In contrast to polybutylmethacrylate, where the proliferation of vascular smooth muscle cells (VSMCs) was excellent but that of endothelial cells was very low, the copolymer containing 11% of dextran was excellent for endothelial cells but very limited for VSMCs. An in vitro wound assay demonstrated that copolymer with 11% dextran is even more favorable for endothelial cell migration than tissue-culture polystyrene. Increasing the dextran content in the copolymers decreased the proliferation for both vascular cell types. Altogether, these results show that transparent and water-insoluble films made from copolymers of dextran and butylmethacrylate copolymers with an appropriate composition could enhance endothelial cell proliferation and migration. Therefore, a potential benefit of this approach is the availability of surfaces with tunable properties for the endothelialization of materials.
Sidi Mohamed Derkaoui, Amélie Labbé, Agung Purnama, Virginie Gueguen, Christel Barbaud, Thierry Avramoglou, Didier Letourneur, Acta Biomaterialia 6 (2010) 3506–3513

B3311 – Selective oxidation of glycerol with O2 catalyzed by low-cost CuNiAl hydrotalcites

A series of CuNiAl hydrotalcites (HTs) were prepared and used to the selective oxidation of glycerol with O2. The results revealed that elemental composition, structures and the surface properties of the obtained catalysts significantly influenced their catalytic performance. Among them, amino-functionalized CuNiAl-HTs showed excellent catalytic performance due to their enhanced surface Lewis basicity. Under the optimal reaction conditions, the highest conversion of glycerol reached 68.1% with 76% of the selectivity to glyceric acid; moreover, the catalytic performance remained after being recycled 6 times.
Gongde Wu, Xiaoli Wang, Yuan Huang, Xianfeng Liu, Fang Zhang, Keqiang Ding, Xiaolan Yang, Journal of Molecular Catalysis A: Chemical 379 (2013) 185– 191

B3300 – Ageing study of Cu–Al–Be hypoeutectoid shape memory alloy

Thermal ageing at constant temperature (350 °C) and under systematically designed temperature-varying conditions were performed on the metastable austenitic phase of hypoeutectoid Cu–Al–Be shape memory alloy. Thermal precipitations and their effects on the alloy global microstructure were studied by DSC, XRD and SEM techniques. Precipitations of equilibrium phases (? + ?2) within the temperature range of 330–370 °C, and their generalization by a discontinuous mechanism for an ageing time of 864 ks (240 h), were identified and analyzed. The results of this study are expected to benefit the applications of copper-based shape memory alloys under various thermal conditions
S.M. Chentouf, M. Bouabdallah, H. Cheniti, A. Eberhardt, E. Patoor, A. Sari, Materials Characterization 61 (2010) 1187-1193

B3310 – Interaction of CO probe molecules with Cu(+) in MCM-22 zeolite

The interaction of CO probe with copper exchanged MCM-22 zeolite is studied. Particularly, the heterogeneity of Cu(+) ions is examined. For this purpose, combined CO adsorption microcalorimetry with FTIR of CO adsorption/desorption at RT and elevated temperature is originally exploited. Contribution brings the first experimental evidence for three families of Cu(+) ions differing in the interaction energy with CO and exhibiting Qdiff around 107, 100 – 97 and ?92 kJ mol?1, respectively. The energy distribution determined from calorimetry and desorption curves is due to copper coordination differences. Despite wide energetic distribution of carbonyls, only two bands in IR spectra at 2159 and 2150 cm?1 are observed. Similarly to other zeolites, Cu(+) loses its original coordination to framework during the CO adsorption. The preferred trigonal planar geometry with CO and two zeolite oxygen gives rise to the band at 2159 cm?1. Peculiarly for MCM-22, significant amount of Cu(+) ions stay three-coordinated to the zeolite after CO adsorption, relate to mediate interaction energies and correspond to the band at 2150 cm?1. Characteristic changes on the IR spectrum revealed that the enhanced movement of ions after CO exposure occurs at higher temperature. The influence of zeolite composition, namely Cu loading and Si/Al ratio, on the character of IR spectrum and population of energetic components is discussed.
Karel Frolich, Roman Bulánek, Eva Frýdová, Microporous and Mesoporous Materials (2013)

B3309 – Excess second-order thermodynamic derivatives of the {2-propanol + water} system from 313.15 K to 403.15 K up to 140 MPa. Experimental and Monte Carlo simulation study

In this work, the density of the aqueous solution of 2-propanol was measured from atmospheric pressure up to 140 MPa in the 313.15–403.15 K temperature interval throughout the composition range by using a vibrating tube densimeter. From these data, the volume, the isobaric thermal expansivity and the isothermal compressibility were derived using usual procedures, as well as their respective excess properties. Likewise, measurements of the isobaric heat capacity of the system were carried out by a Calvet calorimeter at p = 0.1, 20, 40 MPa from 313.15 K to 393.15 K at various concentrations of the alcohol. All this rich experimental information has been compared with Monte Carlo simulations, which were performed in coincident thermodynamic conditions by using a potential based on the OPLS for 2-propanol and the TIP4P/2005 for water, with the Lorentz–Berthelot mixture rules for determining crossing interactions. They were found to be in reasonable agreement with all observations. Likewise, the experimental results were compared with data previously reported in the field in order to further ensure the reliability of this work.
Paula Gómez-Álvarez, Diego González-Salgado, Jean-Patrick Bazile, David Bessieres, Frederic Plantier, Fluid Phase Equilibria 358 (2013) 7– 26

B3308 – Effect of hydrogen on the cracking mechanisms of cycloalkanes over zeolites

Hydrocracking of secondary interest refinery streams (high aromatic content) can yield valuable products for transportation and petrochemical industry. In order to promote the hydrogenation and cracking steps, a bifunctional catalyst (metal + acid function) is required. We have studied the effect of the operating conditions on cycloalkane (product of aromatic hydrogenation) ring opening over a monofunctional HZSM-5 zeolite, by focusing on the effect of hydrogen in the cracking mechanisms. Methylcyclohexane has been selected as the test reactant and the conditions used corresponds to temperature, 250–450 °C; space velocity, 0.7–1.1 h?1; pressure, 2–80 bar; hydrogen/methylcyclohexane molar ratio, 1–79; conversion, 0–100% (integral reactor). At these conditions the zeolite catalyses hydrogenation as well as cracking (bifunctional capabilities), thus the cracking mechanisms are directly affected by hydrogen as products (alkenes) and intermediates (carbenium ions) are saturated. The overall effect of rising hydrogen partial pressure is an enhancement of (hydro)isomerization and monomolecular cracking, that is, an increase of the yield/selectivity of methane, ethane, penthane and isoalkanes.
Pedro Castano, José M. Arandes, Martin Olazar, Javier Bilbao, Barbara Pawelec, Ulises Sedran, Catalysis Today 150 (2010) 363–367

B3317 – Hydrothermal synthesis and characterization of zirconia based catalysts

In this work, three equimolar mixed oxides ZrO2/CeO2, ZrO2/TiO2, ZrO2/La2O3 and a reference ZrO2 have been synthesized by hydrothermal method. The structural and surface properties of these materials have been fully characterized by X-ray diffraction, transmission electron microscopy, surface area measurement, chemical analysis, XPS, infrared spectroscopy after adsorption of pyridine and adsorption microcalorimetry of NH3 and SO2 probe molecules. All investigated mixed oxides are amphoteric and possess redox centers on their surface. Moreover, hydrothermal synthesis leads to catalysts with higher surface area and with better acid–base properties than classical coprecipitation method. Both Lewis and Brønsted acid sites are present on the surface of the mixed oxides. Compared to the other samples, the ZrO2/TiO2 material appears to be the best candidate for further application in acid–base catalysis.
T. Caillot, Z. Salama, N. Chanut, F.J. Cadete Santos Aires, S. Bennici ,A. Auroux, Journal of Solid State Chemistry 203 (2013) 79–85

B3316 – Heat generation behavior during charging and discharging of lithium-ion batteries after long-time storage

Thermal design and management are important for lithium-ion batteries (LIBs) to prevent thermal runaway under normal and abnormal conditions such as overcharge and short circuit. A sound understanding of the heat generation behaviors of LIBs is needed for their thermal design and management. Since battery characteristics such as capacity and power capability degrade with time and the number of cycles, one can infer that the amount of heat generated by LIBs may also be changed by this degradation. Calorimetry is an effective method of studying the heat generation mechanisms of LIBs. In this study, we apply calorimetry to characterize the heat generation behavior of LIBs during charging and discharging after degradation due to long-time storage. At low rates of charging and discharging, such as 0.1C, significant differences dependent on the degree of degradation are not observed. On the contrary, more degraded batteries exhibit greater heat generation related to overvoltage increase at high rates of charging and discharging, such as 1 C. The solution resistance increase is particularly striking in an LIB stored at 50 °C. The chief cause of this increase may be leakage of electrolyte solution, resulting in greater heat generation at high rates of charging and discharging.
Yoshiyasu Saito, Masahiro Shikano, Hironori Kobayashi, Journal of Power Sources 244 (2013) 294-299

B3315 – Experimental and numerical study of annular PCM storage in the presence of natural convection

Latent thermal energy storage (TES) systems have shown growing potential in matching the production to the demand in Concentrated Solar Power (CSP) systems. Indeed, the improved storage density and the constant temperature release of energy allow for more compact heat exchanger design and simplify system management. The shell and tubes heat exchanger is the most promising technology, owing to its low cost. However, phase change phenomena occurring during PCM melting (charge) and PCM solidification (discharge) need to be carefully controlled. To better understand the heat exchange involved in this exchanger type, an annular latent storage unit filled with paraffin RT35 is experimentally and numerically studied. A testing loop with visualisation is built to analyse the influence of the heat transfer fluid (HTF) injection side on the system. The experimental test section is modelled with CFD simulations to explain the charge and discharge results. The combined study proves that an injection side coupled with free convection heat transfer mechanism influences the evolution of the PCM melting front. To conclude, a top injection for charge and a bottom one for discharge are recommended.
Martin Longeon, Adèle Soupart, Jean-François Fourmigué, Arnaud Bruch, Philippe Marty, Applied Energy 112 (2013) 175–184

B3314 – Vapour pressures of selected organic compounds down to 1 mPa, using mass-loss Knudsen effusion method

A recently developed Knudsen effusion apparatus was improved and used for measurements of vapour pressures of selected organic compounds. Calorimetric studies were conducted using a Calvet-type calorimeter, complementing the information obtained for the vapour pressures and facilitating the modelling and analysis of the data. Vapour pressures of benzoic acid, a reference substance, were determined at temperatures between 269 K and 317 K, corresponding to a pressure range from 2 mPa to 1 Pa, extending the range of results available in the literature to lower pressures. Benzanthrone was studied between temperatures 360 K and 410 K (5 mPa–1 Pa) in order to test the apparatus at higher temperatures. Values presented in the literature for the vapour pressure of solid n-octadecane, one of the most promising compounds to be used as “phase change material” for textile applications, were found inconsistent with the triple point of the substance. Sublimation pressures were measured for this compound between T = 286 K and 298 K (2–20 mPa) allowing the correction of the existing values. Finally, vapour pressures of diphenyl carbonate, a compound of high industrial relevance for its use in the production of polycarbonates, were determined from T = 302 K to 332 K (0.02–1 Pa).
José M. S. Fonseca, Nikola Gushterov, Ralf Dohrn, J. Chem. Thermodynamics (2013)

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