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5631 articles

B3117 – Thermodynamics of ???? phase transformation and heat capacity measurements in Ti–15 at% Nb alloy

The phase stability of Ti–15 at% Nb alloy has been studied in the temperature range 466–1258 K using inverse drop calorimetry. In the annealed condition, the alloy consists of orthorhombic ??-martensite and bcc ? phases. The calorimetry experiments indicated the occurrence of two phase changes upon heating. They are (i) precipitation of hexagonal ? phase at 582±2 K followed by (ii) ???? in the temperature domain 836–985±2 K. The enthalpy change due to ? formation is small; however, the ???? phase transformation is associated with a measurable enthalpy effect of 57±3 J g?1. Since ???? phase change occurs over a temperature interval, the measured enthalpy in the transformation domain derives from two principal contributions, namely, the matrix contribution coming from untransformed ??-martensite and ? phase mix and another transformational component arising from continuous ???? phase change. Since the fractional extent of ???? transformation varies continuously with temperature the transformation enthalpy also exhibits similar temperature dependence. This aspect is modeled using Kolmogorov–Johnson–Mehl–Avrami formalism for treating the diffusional transformation kinetics. Further, the measured enthalpy variation with temperature has been subjected to standard analytical treatment to obtain a comprehensive thermodynamic description of entire ??+? region.
A. Josephine Prabha, S.Raju, B.Jeyaganesh, Arun Kumar Rai, Madhusmita Behera, M. Vijayalakshmi, G.Paneerselvam, I.Johnson, Physica B406(2011)4200–4209

B3121 – Insights into the coke deposited on HZSM-5, H? and HY zeolites during the cracking of polyethylene

The effect of the zeolite structure (HZSM-5, H? and HY) on coke deposition during the cracking of high-density polyethylene has been studied by combining the results of multiple spectroscopic and analytical techniques: FTIR, Raman, UV-vis, 13C NMR and coke extraction, followed by GC-MS and 1H NMR analysis. In addition, by combining FTIR and temperature programmed oxidation (TPO) analysis we obtained information on the coke: properties, burn-off, and changes in composition during catalyst regeneration. Samples of the spent catalysts were obtained in a state-of-the-art pilot plant (conical spouted bed reactor) after the continuous treatment of 900g (1g min?1, 15 h) of high-density polyethylene at 500 C, using 30 g of catalyst. The results show that as the pore diameter of the zeolite is increased, bimolecular reactions (hydrogen transfer and oligomerizations), condensations and cyclizations are enhanced, yielding more aromatic coke. Furthermore, the pore topology of the HZSM-5 zeolite improves the flow of coke precursors (also favored by the high flow rate of N2) to the outside of the catalyst; viz. HZSM-5 catalyst preserves its activity for longer.
Pedro Castano, Gorka Elordi, Martin Olazar, Andres T. Aguayo, Bárbara Pawelec, Javier Bilbao, Applied Catalysis B: Environmental 104 (2011) 91–100

B3120 – Evaporation kinetics of volatile liquids and release kinetics of water from a smectite clay: Comparison between experiments and finite element calculations

Numerical calculations of the evaporation kinetics of bulk volatile liquids and of water from smectite clay granules are compared with experimental results. The weight loss of the volatiles is analyzed by thermogravimetry and differential calorimetry. Under the thermodynamic conditions of the experiments, finite element calculations are in good agreement with the experimental data, and an approximate semi-analytical model is developed in order to explain the dependence of the rate of evaporation on the temperature, the chemical species and the carrier gas flow rate. The initial rate of evaporation of water from the clay granule is close to that for bulk water. Its decrease with time is determined mainly by changes in the gas/condensed phase partition given by the equilibrium desorption isotherm, with little limitations due to internal diffusion effects for the present experimental conditions. Its temperature dependence could also be approximately described by an Arrhenius-type equation derived from the semi-analytical model. Further analysis of the experimental measurements reveals steps in the heat of vaporization of water as a function of water concentration, that could be related to the equilibrium desorption isotherm.
Pascal Clausen, Brigitte Watzke, Eric Hughes, Christopher J.G. Plummer, Jan-Anders E. Månson, International Journal of Engineering Science 49 (2011) 1125–1140

B3119 – Mesure et modélisation des conditions de dissociation d’hydrates de gaz stabilisés en vue de l’application au captage du CO2

La capture et la séquestration du CO2 en sortie des usines d'incinération, des centrales thermiques ou des cimenteries est devenu un enjeu mondial. La capture de ce gaz par voie hydrate est une alternative prometteuse. L’objet de cette thèse est l’étude de la stabilité des systèmes d’hydrates mixtes contenant du CO2 et un autre gaz (N2, CH4 et H2) avec l’eau pure, ou encore avec un additif permettant l’abaissement des pressions de formation : le tetrabutylamonium bromure (TBAB), dans une perspective de séparation de gaz. La technique expérimentale que nous avons utilisée est la calorimétrie différentielle programmée (DSC). Elle nous a permis de mesurer les températures et les enthalpies de dissociation des différents systèmes d’hydrates avec l’eau pure : N2, CH4, N2+ CO2, CH4+CO2, H2+CO2 ; mais aussi des systèmes semi-clathrates: CO2+CH4 et CO2+N2 à différents pourcentages massiques de TBAB (10, 20, 30 et 40). La dernière partie de cette thèse concerne la modélisation thermodynamique des semiclathrates, où nous avons développé le cas particulier du système d’hydrate: CH4+TBAB.
Wassila Bouchafaa, Thèse Ecole Polytechnique (Paris) 2011

B3125 – Nanocrystalline Ti2/3Sn1/3O2 as anode material for Li-ion batteries

We prepared nanocrystalline Ti2/3Sn1/3O2 by a coprecipitation method starting from Ti(isopropoxide)4 and SnCl4·5H2O followed by calcination at 600 °C. TEM and XRD measurements reveal crystallite sizes of about 5 nm and a crystal structure equivalent to those of TiO2 rutile and SnO2 cassiterite. The local structure was investigated with 119Sn NMR and Sn Mössbauer spectroscopy. The material was cycled with C/20 at voltages between 3.0 and 0.02 V against Li metal. Specific capacities of 300 mAh g?1 were obtained for 100 cycles with voltage profiles very similar to those of pure SnO2. Faster cycling leads to strong decrease of the capacities but after returning to C/20 the initial values are obtained.
Ibrahim Issac, Marco Scheuermann, Sebastian M. Becker, Elisa Gil Bardají, Christel Adelhelm, Di Wang, Christian Kübel, Sylvio Indris, Journal of Power Sources 196 (2011) 9689– 9695

B3124 – Mechano-chemical reactions in LiBH4 + VCln (n = 2 and 3) mixtures

Mechano-chemical routes to the metathesis reaction 4LiBH4 + VCln ? Li4?nV(BH4)4 + nLiCl (n = 2 and 3) are explored at room and liquid nitrogen temperatures. The produced samples consist of crystalline LiCl and unreacted LiBH4. No other crystalline phases are observed directly by powder X-ray diffraction. The highest reactivity was observed when using VCl3. Two possible reaction paths are proposed in order to explain this result: (a) 2LiBH4 + VCl2 ? 2LiCl + VB2 + 4H2, with ?H = ?188 kJ/mol and (b) 3LiBH4 + VCl3 ? 3LiCl + 1/2B2H6 + VB2 + 9/2H2, with ?H = ?258 kJ/mol. The calculated enthalpy values show that reactions with VCl3 have stronger thermodynamical driving forces than with VCl2, corroborating the experimental results. Still, the different experimental methods lead to the same final products, with longer milling times being necessary to remove the precursor traces in the case of VCl2 and cryomilling. The results shed some light on the efficiency of mechano-chemical methods for the synthesis of mixed metal borohydrides based on LiBH4 and V-chlorides.
Isabel Llamas-Jansa, Nadir Aliouane, Stefano Deledda, Jon Erling Fonneløp, Christoph Frommen, Klaus Lieutenant, Sabrina Sartori, Magnus H. Sørby, Bjørn C. Hauback, Journal of Alloys and Compounds 509S (2011) S684– S687

B3123 – Role of pore structure in the deactivation of zeolites (HZSM-5, H? and HY) by coke in the pyrolysis of polyethylene in a conical spouted bed reactor

The deactivation of three different catalysts used in the cracking of high density polyethylene (HDPE) has been compared. The catalysts used are HZSM-5, H? and HY zeolites agglomerated with bentonite and alumina. The reactions have been carried out in a conical spouted bed reactor at 500 °C, and plastic (high density polyethylene) has been fed in continuous mode (1 g min?1) for up to 15 h of reaction. The HZSM-5 zeolite catalyst gives way to high yields ofC2-C4olefins (57 wt%) and, moreover, it is the one least influenced by deactivation throughout the run, which is explained by the lower deterioration of its physical properties and acidity. The results of temperature program combustion and transmission electron microscopy show that coke growth is hindered in the HZSM-5 zeolite pore structure. The high N2 flow rate used in the conical spouted bed reactor enhances coke precursor circulation towards the outside of the zeolite crystal channels.
G. Elordi, M. Olazar, G. Lopez, P. Castano, J. Bilbao, Applied Catalysis B: Environmental 102 (2011) 224–231

B3122 – Cycle stability of sorption materials and composites for the use in heat pumps and cooling machines

Thermally driven adsorption chillers and heat pumps are a very promising approach toward an efficient use of energy as well as an effective climate protection through reduced CO2 emission of conventional heating and cooling devices. With regard to current market entrance of this technology, this paper presents results on the stability of current available materials like silica gels and zeolites, recently developed materials like aluminophosphates (AlPO) and silica-aluminophosphates (SAPO) and novel materials like metal organic frameworks (MOF) under hydrothermal treatment.Seven materials as powders or granules as well as three composite have been analyzed under continuous thermal cycling in a water vapour atmosphere in order to evaluate their suitability for the use in a periodically working heat pump with water as working fluid.The stability of powders has been analyzed in-situ by thermogravimetry in a first stage short-cycle test. In case of the composite, made up of an active sorption material and a support structure, a cycling-test rig has been developed in order to realize a life-cycle stress. The need for a first stage short-cycle test is demonstrated impressively by the dramatic loss of 40% in sorption capacity of a Cu-BTC sample within the first 15 cycles.
S.K. Henninger, G. Munz, K.-F. Ratzsch, P. Schossig, Renewable Energy 36 (2011) 3043-3049

B3129 – Variation of structure and properties of La1?xSrxCo0.2Fe0.8O(3??) with Sr content: Implications for oxidation activity

The bulk structure, surface characteristics and catalytic properties of Fe-based perovskite-type oxides with the formula La1-xSrxCo0.2Fe0.8O(3??) for x=0.2. 0.4, 0.6 and 0.8 have been investigated as potential anode catalysts for solid oxide fuel cells. The properties were found to strongly depend upon Sr-content, temperature, and environment. The bulk structure shifted towards being oxygen deficient and cubic under atmospheric conditions as the Sr content increased. The oxygen activation was found to be a strong function of Sr content with the catalysts being more active and having a lower activation energy for Sr-rich La1-xSrxCo0.2Fe0.8O3-delta. The materials showed good activity for methane oxidation forming only complete oxidation products and showing no propensity to coke formation, making them a stable potential anode catalyst for SOFCs
Nandita Lakshminarayanan, John N. Kuhn, Hyunkyu Choi, Jean-Marc M. Millet, Umit S. Ozkan, Journal of Molecular Catalysis A: Chemical 336 (2011) 23–33

B3128 – More on the reactivity of olivine LiFePO4 nano-particles with atmosphere at moderate temperature

The changes appearing for LiFePO4-C nano-composites exposed to atmosphere at 12°C have been structurally and chemically examined by the use of TGA, XRD, XPS, Mössbauer, 7Li MAS NMR and electrochemical methods. The results conclude that a highly disordered phase resulting from the aging of LiFePO4 appears on the surface of the grains of the material, is assigned to a phosphate phase and can insert lithium around 2.6V with poor reversibility. The essential role of water has been investigated and clearly demonstrated. Thus, the aging mechanism occurring in hot humid air is completely different from a simple oxidation as well as
Jean-Frédéric Martin, Marine Cuisinier, Nicolas Dupré, Atsuo Yamada, Ryoji Kanno, Dominique Guyomard, Journal of Power Sources 196 (2011) 2155–2163

B3127 – Consequences of the iron–aluminium exchange on the performance of hydrotalcite-derived mixed oxides for ethanol condensation

The effect of the partial and total substitution of aluminium by iron on the performance of different hydrotalcite-derived mixed oxides for the condensation of ethanol for obtaining valuable C4 products (mainly butanol and 1,3,-butadiene) has been studied in this work. Ethanol condensation reactions have been performed in a fixed bed reactor at 0.1 MPa, WHSV = 0.215 h?1 and 473–723 K. Three different hydrotalcite-derived mixed oxide with an atomic Mg2+/M3+ ratio of 3 (namely Mg6Al2O9, Mg6AlFeO9 and Mg6Fe2O9) have been prepared by a previously optimized procedure, tested as catalyst for the above mentioned reaction and characterized by TG–DTG, NH3-TPD, CO2 adsorption (calorimetric, TG–DTG and FTIR), Mossbauer Spectroscopy and TPR. The substitution of Al3+ by Fe3+ in the structure of the resulting mixed oxide leads to a slight decrease of the basic sites and a more marked decrease of the concentration of acid sites, being the concentration of these last sites negligible when the Al3+ cation is completely replaced by Fe3+. Accordingly, Mg–Fe mixed oxide is the most selective catalyst for the formation of C4 compounds, especially butanol. The almost total abatement of the acid sites of this material largely decrease the selectivity for ethanol dehydration, resulting in an increase of the formation of the dehydrogenation product (acetaldehyde), key reactant for condensation reactions.
Marta León, Eva Díaz, Aurelio Vega, Salvador Ordónez, Aline Auroux, Applied Catalysis B: Environmental 102 (2011) 590–599

B3126 – A kinetic study of CO2 desorption from basic materials: Correlation with adsorption properties

The kinetics of the CO2 desorption from basic materials has been studied in this work. For this purpose, temperature-programmed desorption of CO2 from different basic materials (hydrotalcite-derived alkaline mixed oxides and enhanced magnesium oxides) has been determined by thermogravimetry, and mathematically analysed by two different approaches: Kissinger and isoconversional methods. We present in this work a modification of the Kissinger Method for taking into account complex desorption profiles. According to this modification, TPD profile is deconvoluted into the sum of Gaussian peaks, Kissinger methodology being applied to these peaks. Both approaches provide kinetic parameters with physical sense, which explains the different behaviour of these adsorbents in terms of the interaction of the CO2 molecule with the active sites of the adsorbents. Obtained values of activation energy (75–90 kJ/mol for the weak sites and 100–160 kJ/mol for the strong sites) and pre-exponential factors (107–1012 min?1) were checked for physicochemical consistence (considering both the order of magnitude and the consistence with adsorption enthalpies), and were correlated with adsorption properties measured by microcalorimetry.
Marta León, Eva Díaz, Aurelio Vega, Salvador Ordónez, Chemical Engineering Journal 175 (2011) 341– 348

B3137 – Co-feeding water to attenuate deactivation of the catalyst metallic function (CuO–ZnO–Al2O3) by coke in the direct synthesis of dimethyl ether

Co-feeding water with syngas in the direct synthesis of dimethyl ether has been studied in order to reduce the deactivation by coke deposition on the CuO–ZnO–Al2O3 metallic function in the CuO–ZnO–Al2O3/?-Al2O3 bifunctional catalyst. The runs (synthesis of methanol and synthesis of DME) have been carried out in an isothermal fixed bed reactor under conditions avoiding catalyst deactivation due to the sintering of the metallic function (<325 °C) and the deactivation of the acid function (with an excess of ?-Al2O3 in the catalyst). The results of long-term experiments evidence that water in the reaction medium attenuates coke deposition during the methanol synthesis step, which is the limiting one. Water is understood to partially inhibit the formation of coke precursor methoxy ions. Furthermore, the formation of paraffins is attenuated by co-feeding water.
Irene Sierra, Javier Erena, Andrés T. Aguayo, José M. Arandes, Martin Olazar, Javier Bilbao, Applied Catalysis B: Environmental 106 (2011) 167– 173

B3136 – The quasicrystalline phase formation in Al–Cu–Cr alloys produced by mechanical alloying

Almost single-phase decagonal quasicrystal with periodicity of 1.26 nm along 10-fold axis was produced in Al69Cu21Cr10 and Al72.5Cu16.5Cr11 alloys using combination of mechanical alloying (MA) and subsequent annealing. Phase transformations of as-milled powders depending on annealing temperature in the range of 200–800 °C are examined. Since the transformations can be explained based on kinetic and thermodynamic reasons it seems that applied technique (short preliminary MA followed by the annealing) permits to produce the equilibrium phases rather than metastable ones.
T.A. Sviridova, A.P. Shevchukov, E.V. Shelekhov, D.L. Diakonov, V.V. Tcherdyntsev, S.D. Kaloshkin, Journal of Alloys and Compounds 509S (2011) S299–S303

B3135 – Nanosized copper ferrite materials:Mechanochemical synthesis and characterization

Nanodimensional powders of cubic copper ferrite are synthesized by two-steps procedure of co-precipitation of copper and iron hydroxide carbonates, followed by mechanochemical treatment. X-ray powder diffraction, Mössbauer spectroscopy and temperature-programmed reduction are used for the characterization of the obtained materials. Their catalytic behavior is tested in methanol decomposition to hydrogen and CO and total oxidation of toluene. Formation of nanosized ferrite material is registered even after one hour of milling time. It is established that the prolonging of treatment procedure decreases the dispersion of the obtained product with the appearance of Fe2O3. It is demonstrated that the catalytic behavior of the samples depends not only on their initial phase composition, but on the concomitant ferrite phase transformations by the influence of the reaction medium.
Elina Manova, Tanya Tsoncheva, Daniela Paneva, Margarita Popova, Nikolay Velinov, Boris Kunev, Krassimir Tenchev, Ivan Mitov, Journal of Solid State Chemistry 184 (2011) 1153–1158

B3134 – Influence of superheat before quench on the structure and stability of NiP metallic glasses studied by neutron scattering techniques

The temperature dependent structure of Ni81P19 metallic glasses, rapidly quenched from melts which have undergone different heat treatments, has been investigated by small angle neutron scattering and neutron diffraction. All samples contain in the as-quenched state particles or clusters of a very wide range of sizes. These are amorphous regions of different compositions in a large composition range and/or crystallites of another Ni composition than the matrix, such as Ni3P, Ni5P2 or Ni12P5, or even “voids”. The results can be interpreted within the concept of a heterogeneous structure existing in eutectic melts in a certain temperature range. Comparison is made with results from the literature on samples from the same ribbons investigated by calorimetry as well as by fractography and Weibull analysis of mechanical properties.
M. Calvo-Dahlborg, U. Dahlborg, J.M. Ruppert, Journal of Non-Crystalline Solids 357 (2011) 798–808

B3133 – Phase transitions in hydrothermal K2HPO4 solutions

A 0.1 M potassium phosphate (K2HPO4) solution was reacted in a flow-through cell pressurized to 22 MPa. Reduced light transmission through the cell windows was observed at a setpoint temperature ?400 °C, along with a decrease in effluent conductivity, but with no effect on flow. These observations suggest solution separation at ?360 °C, with accumulation of a salt-concentrated liquid in the cell body and transition of a dilute liquid to a supercritical fluid at temperature >374 °C. High-pressure differential scanning calorimetry experiments confirm an onset temperature of 354 °C with an endothermic transition at 377 °C and 22 MPa. For apparent density, ? = 150–500 kg/m3, the average transition temperature for 0.1 M solutions, 375 ± 5 °C, is slightly elevated relative to that of water at 371 ± 4 °C. Highest deviation for 1.0 M solutions, 365 ± 15 °C, is attributed to increased K2HPO4 hydrolysis and polymerization reactions
Ashaki A. Rouff, Stefan Rabe, Frédéric Vogel, J. of Supercritical Fluids 57 (2011) 207–212

B3132 – Synthesis and decomposition mechanisms of ternary Mg2CoH5 studied using in situ synchrotron X-ray diffraction

A ternary Mg2CoH5 hydride was synthesized using a novel method that relies on a relatively short mechanical milling time (1 h) of a 2:1 MgH2-Co powder mixture followed by sintering at a sufficiently high hydrogen pressure (>85 bar) and heating from RT to 500 °C. The ternary hydride forms in less than 2.5 h (including the milling time) with a yield of ?90% at ?300 °C. The mechanisms of formation and decomposition of ternary Mg2CoH5 were studied in detail using an in situ synchrotron radiation powder X-ray diffraction (SR-PXD). The obtained experimental results are supported by morphological and microstructural investigations performed using SEM and high-resolution STEM. Additionally, thermal effects occurring during the desorption reaction were studied using DSC. The morphology of as-prepared ternary Mg2CoH5 is characterized by the presence of porous particles with various shapes and sizes, which, in fact, are a type of nanocomposite consisting mainly of nanocrystallites with a size of ?5 nm. Mg2CoH5 decomposes at approximately 300 °C to elemental Mg and Co. Additionally, at approximately 400 °C, MgCo is formed as precipitates inserted into the Mg–Co matrix. During the rehydrogenation of the decomposed residues, prior to the formation of Mg2CoH5, MgH2 appears, which confirms its key role in the synthesis of the ternary Mg2CoH5.
M. Norek, T.K. Nielsen, M. Polanski, I. Kunce, T. P?ocinski, L.R. Jaroszewicz, Y. Cerenius, T.R. Jensen, J. Bystrzycki, International Journal of Hydrogen Energy 36(2011) 10760-10770

B3131 – Synthesis, characterization and catalytic performance of titania supported VPO catalysts for the ammoxidation of 3-picoline

Series of vanadium phosphorus oxide (VPO) catalysts supported over titania (anatase) were synthesised with varying contents of VPO (5–50 wt%). These solids were characterised by ICP-OES, TG/DTA, BET, XRD, FTIR (Py-ads) and XPS. The catalytic activity was evaluated for ammoxidation of 3-picoline (3-pic) to nicotinonitrile (NN) in a fixed bed catalytic reactor. Thermal analysis provided good hints on the phase transformation of VHP precursor into active VPP phase at around 400 °C. BET surface areas and pore volumes are found to depend on VPO loading and varied in the range from 70 m2/g to 133 m2/g. XRD demonstrates the formation of (VO)2P2O7 (VPP) phase. XPS showed that an average oxidation state of vanadium around 4.0, which is found to be unaltered in the spent samples. FTIR (Py-ads) revealed the presence of both Lewis and Brønsted sites with varying proportions, which again depend upon VPO loading. Correlation of acidic properties (Lewis and Brønsted acid sites) of the catalysts with that of performance of catalysts was explored. VPO loading has a clear influence on the acidic properties and thereby catalytic activity and selectivity. Catalytic results showed that the supported catalysts gave better performance compared to bulk VPO. Yield of NN increased up to 20 wt% VPO loading and then decreased with further increase in VPO content. Among all catalysts tested, the 20 wt% VPO/TiO2 exhibited the best performance (X-3-pic = ca. 100% and Y-NN = 83%).
V.N. Kalevaru, N. Madaan, A. Martin, Applied Catalysis A: General 391 (2011) 52–62

B3130 – Effect of additional B-site transition metal doping on oxygen transport and activation characteristics in La0.6Sr0.4(Co0.18Fe0.72X0.1)O3?? (where X = Zn, Ni or Cu) perovskite oxides

The bulk structure, surface characteristics and catalytic properties of perovskite-type oxides with the formula La0.6Sr0.4(Co0.18Fe0.72X0.1)O3?? with X = Zn, Ni and Cu have been investigated. With additional B-site doping with divalent cations, the oxygen vacancy generation properties were significantly enhanced, while still maintaining a stable perovskite structure. The Zn-doped sample showed the best performance and was further characterized for surface structure and properties. CO2 TPD and methane oxidation experiments were conducted to gauge the oxygen activation and oxygen mobility and the Zn-doped catalyst showed improved performance over the baseline La0.6Sr0.4Co0.2Fe0.8O3?? catalyst, making it a potential SOFC cathode catalyst.
Nandita Lakshminarayanan, Hyunkyu Choi, John N. Kuhn, Umit S. Ozkan, Applied Catalysis B: Environmental 103 (2011) 318–325

B3140 – Thermochemical study of three dibromophenol isomers

This work reports the standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, ?fHm?(g), of 2,4-, 2,6-, and 3,5-dibromophenol, at T = 298.15 K, respectively, as (59.6 ± 2.6) kJ · mol?1, (49.1 ± 2.2) kJ · mol?1 and (39.5 ± 2.0) kJ · mol?1. These experimental values were derived from the measurements of the standard molar enthalpies of formation, in the crystalline phase, ?fHm?(2,4-dibromophenol,cr)=-(140.9±2.1)kJ·mol-1, ?fHm?(2,6-dibromophenol,cr)=-(132.5±1.6)kJ·mol-1 and ?fHm?(3,5-dibromophenol,cr)=-(134.5±1.7)kJ·mol-1, at the same reference temperature, achieved from the standard molar enthalpies of combustion, in oxygen, to yield CO2(g) and HBr·600H2O(l), measured by rotating-bomb combustion calorimetry, together with measurements of the standard molar enthalpies of sublimation, at T = 298.15 K, as ?crgHm?(2,4-dibromophenol)=(81.3±1.5)kJ·mol-1, ?crgHm?(2,6-dibromophenol)=(83.4±1.5)kJ·mol-1 and ?crgHm?(3,5-dibromophenol)=(94.3±1.8)kJ·mol-1, obtained using the Calvet high temperature vacuum sublimation technique. The standard molar enthalpy of sublimation, at T = 298.15 K, for the 3,5-dibromophenol was also determined from the temperature–vapour pressure dependence, obtained by the Knudsen mass loss effusion method, ?crgHm?(3,5-dibromophenol)=(95.0±1.1)kJ·mol-1. For this isomer it is also reported the standard (p° = 0.1 MPa) molar entropy and Gibbs energy of sublimation, at T = 298.15 K. The experimental values of the gas-phase enthalpies of formation of each compound were compared with estimates using the empirical scheme developed by Cox and with the calculated values based on density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional at the 6-311++G(d,p) basis set. These two methodologies were also used to estimate the enthalpies of formation in the gas-phase of the 2,3-, 2,5-, and 3,4-dibromophenol
Ana I.M.C. Lobo Ferreira, Manuel A.V. Ribeiro da Silva, J. Chem. Thermodynamics 43 (2011) 227–234

B3139 – Partial oxidation of methane on Pt-supported lanthanide doped ceria–zirconia oxides: Effect of the surface/lattice oxygen mobility on catalytic performance

Partial oxidation of methane into syngas at short contact times (5–15 ms) was studied in both steady-state and transient modes at temperatures up to 850 °C in realistic feeds (CH4 content up to 20%, CH4/O2 = 2) with a minimum impact of mass and heat transfer for structured catalysts carrying Pt/Ln0.3Ce0.35Zr0.35O2?y (Ln = La, Pr, Gd) as thin layers on walls of corundum channel substrates. Oxygen mobility and reactivity of the active phase were characterized by oxygen isotope heteroexchange, temperature-programmed O2 desorption and CH4 reduction, isothermal pulse reduction by methane with wide variation of CH4 concentrations and TAP pulse studies. Experimental data point towards a selective oxidation of methane into syngas via a direct route with oxygen-assisted methane activation. This mechanistic feature is related to the strong Pt-support interaction stabilizing highly dispersed oxidic Pt species less active in CH4 and syngas combustion than metallic Pt clusters. Support activates O2 molecules and supplies active oxygen species to Pt sites. A high rate of oxygen diffusion on the surface and in the bulk of the support and Pt-support oxygen spillover stabilizes Pt in a well dispersed partially oxidized state while preventing coking at high concentrations of CH4 in the feed.
Vladislav A. Sadykov, Nathalia N. Sazonova, Aleksei S. Bobin, Vitalii S. Muzykantov, Elena L. Gubanova, Galina M. Alikina, Anton I. Lukashevich, Vladimir A. Rogov, Eugenia N. Ermakova, Ekaterina M. Sadovskaya, Nathalia V. Mezentseva, Ekaterina G. Zevak, Sergei A. Veniaminov, Martin Muhler, Claude Mirodatos, Yves Schuurman, Andre C. van Veen, Catalysis Today 169 (2011) 125–137

B3138 – Structure and surface chemistry in crystalline mesoporous (CeO2-?)–YSZ

Mesoporous metal oxides (CeO2-?)-YSZ have been synthesized by a versatile direct synthesis method using ionic cetyltrimethylammonium bromide (CTAB) and different nonionic (block copolymers) as surfactants and urea as hydrolyzing agent. The synthesis was realized at pH = 9 using tetraethylammonium hydroxide (TEAOH) as pH mediator. Calcination at 550 °C led to the formation of crystalline metal oxides with uniform mesoporosity. The obtained materials have been characterized by thermogravimetric analysis (TG-DTG), wide and small-angle X-ray diffraction (XRD), Raman spectroscopy, Brunauer, Emmett and Teller (BET) surface area analysis, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). All the obtained materials exhibits mesoporous structure, crystalline structure indexed in a cubic symmetry, showing a high surface area, a uniform and narrow pore size distribution, spherical morphology typical for the mesoporous materials. The crystalline and mesoporous structures, surface chemistry and stoichiometry for the samples synthesized using ionic and nonionic surfactants have been discussed.
Simona Somacescu, Viorica Parvulescu, Petre Osiceanu, Jose Maria Calderon-Moreno, Bao-Lian Su, Journal of Colloid and Interface Science 363 (2011) 165–174

B3141 – Thermochemical study of 2,5-dimethyl-3-furancarboxylic acid, 4,5-dimethyl-2-furaldehyde, and 3-acetyl-2,5-dimethylfuran

The standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous state, at T = 298.15 K, for 2,5-dimethyl-3-furancarboxylic acid, 3-acetyl-2,5-dimethylfuran, and 4,5-dimethyl-2-furaldehyde were derived from the values of the standard molar enthalpies of formation, in the condensed phase, and the standard molar enthalpies of phase transition from the condensed to the gaseous state. The values of the standard molar enthalpies of formation of the compounds in the condensed phases were calculated from the measurements of the standard massic energies of combustion obtained by static bomb combustion calorimetry. The enthalpies of vaporization/sublimation were measured by Calvet high temperature microcalorimetry. For 2,5-dimethyl-3-furancarboxylic acid the standard enthalpy of sublimation was also calculated, by the application of the Clausius–Clapeyron equation, to the temperature dependence of the vapor pressures measured by the Knudsen effusion technique.
Manuel A.V. Ribeiro da Silva, Luísa M.P.F. Amaral, J. Chem. Thermodynamics 43 (2011) 1–8

B3146 – Loading rate dependency of maximum nanoindentation depth in nano-grained NiTi shape memory alloy

We examined the effect of loading rate on maximum nanoindentation depth for nano-grained superelastic NiTi shape memory alloy during stress-induced phase transformation. The depth decreases significantly with increasing loading rate. It is argued that the observed rate dependency is attributed to the release and transfer of latent heat during indentation and the temperature dependence of the material's transition stress. Dimensional analysis further shows that the depth is mainly governed by the normalized average stress in the phase transition zone and the ratio of heat conduction time over loading time. Experimental results support the rationale.
Abbas Amini, Yongjun He, Qingping Sun, Materials Letters 65 (2011) 464–466

B3145 – When theory and experiment hold hands: The thermochemistry of ?-pyrone derivatives

In this work, we have determined the experimental standard (p?=0.1MPa) molar enthalpies of formation, in the gas phase, of 2,6-dimethyl-4-pyrone ?(261.5 ± 2.6) kJ · mol?1 and 2-ethyl-3-hydroxy-4-pyrone ?(420.9 ± 2.8) kJ · mol?1. These values were obtained by combining the standard molar enthalpy of formation in the condensed phase, derived from combustion experiments in oxygen, at T = 298.15 K, in a static bomb calorimeter, with the standard molar enthalpy of sublimation, at T = 298.15 K, obtained by Calvet microcalorimetry. Additionally, high-level density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional with extended basis sets have been performed for these two compounds. Good agreement was obtained between the experimental and computational results. Using the same methodology, we calculated the standard molar enthalpy of formation of gaseous 2-methyl-3-hydroxy-4-pyrone.
Clara C.S. Sousa, M. Agostinha R. Matos, Victor M.F. Morais, J. Chem. Thermodynamics 43 (2011) 1159–1163

B3144 – Experimental study on the thermochemistry of 3-nitrobenzophenone, 4-nitrobenzophenone and 3,30-dinitrobenzophenone

The standard (p° = 0.1 MPa) molar enthalpies of combustion, ?cHm?, for the 3- and 4-nitrobenzophenones and for the 3,3?-dinitrobenzophenone, in the crystalline state, were determined, at the temperature T = 298.15 K, using a static bomb combustion calorimeter. For these compounds, the standard molar enthalpies of sublimation, ?crgHm?, at T = 298.15 K, were determined by Calvet microcalorimetry. For the 3- and 4-nitrobenzophenones the vapour pressures as function of temperature were measured by the Knudsen effusion technique and the standard molar enthalpies of sublimation, ?crgHm?, at T = 298.15 K, were derived by the Clausius–Clapeyron equation.
Manuel A.V. Ribeiro da Silva, Luísa M.P.F. Amaral, Rodrigo V. Ortiz, J. Chem. Thermodynamics 43 (2011) 546–551

B3143 – Thermochemical study of some dichloroacetophenone isomers

The standard (p?=0.1MPa) molar enthalpies of formation in the condensed phase, ?fHm?(cr,l), for 2?,4?-, 2?,5?-, and 3?,4?-dichloroacetophenones were derived from the standard molar energies of combustion, ?cUm? in oxygen, to yield CO2(g) and HCl · 600H2O(l), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of vapourization or sublimation, ?cr,lgHm?, of these compounds, at T = 298.15 K were determined by Calvet microcalorimetry. For the 3?,4?-dichoroacetophenone, the standard molar enthalpy of sublimation, at T = 298.15 K, was derived by the Clausius–Clapeyron equation, from the temperature dependence of the vapour pressures of this compound, measured by the Knudsen effusion technique. From the values of ?fHm?(cr,l) and ?cr,lgHm? the standard molar enthalpies of formation of the three isomers, in the gaseous phase, ?fHm?(g), at T = 298.15 K were derived and compared with the same parameters estimated by the Cox Scheme.
Manuel A.V. Ribeiro da Silva, Luísa M.P.F. Amaral, J. Chem. Thermodynamics 43 (2011) 255–261

B3142 – Experimental and computational study on the energetics of 10,11-dihydro-5H-dibenzo[a,d]cycloheptene (dibenzosuberane)

A study on the molecular structure and energetics of 10,11-dihydro-5H-dibenzo[a,d]cycloheptene (dibenzosuberane) was performed combining experimental calorimetric techniques and high level computational calculations. In the experimental work, the solid phase standard (p?p? = 0.1 MPa) molar enthalpy of formation of 10,11-dihydro-5H-dibenzo[a,d]cycloheptene was derived from its standard massic energy of combustion, at T = 298.15 K, measured by static bomb combustion calorimetry, in oxygen. The respective standard molar enthalpy of sublimation, at T = 298.15 K, was measured by Calvet microcalorimetry enabling the calculation of the standard molar enthalpy of formation (161.4 ± 3.7) kJ · mol?1, in the gaseous phase, at T = 298.15 K. In addition, computational calculations were performed using the density functional theory with the B3LYP hybrid functional and extended basis sets in order to obtain the molecular structure of 10,11-dihydro-5H-dibenzo[a,d]cycloheptene and that of related molecules. Estimates of the standard molar enthalpy of formation, in the gaseous phase, at T = 298.15 K, for 10,11-dihydro-5H-dibenzo[a,d]cycloheptene were performed using three different methods: G3(MP2)//B3LYP, MC3BB, and MC3MPW and appropriate homodesmic reactions. Computational estimates are in very good agreement with the experimental value.
Margarida S. Miranda, M. Agostinha R. Matos, Victor M.F. Morais, Joel F. Liebman, J. Chem. Thermodynamics 43 (2011) 364–370

B3150 – Effects of copper filler sizes on the dielectric properties and the energy harvesting capability of nonpercolated polyurethane composites

Nonpercolated composites based on polyurethane (PU) filled with low concentrations copper (Cu) powders of varying sizes were studied as electrostrictive materials for mechanical energy harvesting. The dispersion of the fillers within the polymeric matrix was investigated by scanning electron microscopy, and results showed a relatively homogeneous dispersion for the microsized fillers and the existence of agglomerates for their nanosized counterparts. Differential scanning calorimetry measurements displayed that there occurred no interaction between the polymeric matrix and the microsized fillers whereas the nanosized fillers slightly enhanced the glass transition of the soft segments of PU and significantly affected the recrystallization temperature. The dependence of the dielectric properties of the composites as a function of the filler volume fraction and filler size was investigated over a broad range of frequencies, showing an increase in the permittivity when fillers were used. This increase was more pronounced for the composites containing nanosized fillers. The measurement of the harvested current and of the harvested power also demonstrated an enhancement of the energy harvesting capability when nanofillers were employed. From the experimental data, it appeared that the electrostrictive coefficient Q was not proportional to the inverse ratio of the permittivity and the Young modulus for the studied composites. Finally, analytical modeling of the harvested current and of the harvested energy offered an accurate description of the experimental data.
C. Putson, L. Lebrun, D. Guyomar, N. Muensit, P.-J. Cottinet, L. Seveyrat, B. Guiffard, J. Appl. Phys. 109, 024104 (2011)

B3160 – Study of the degradation mechanisms of polyethylene during reprocessing

The present work aims at evaluating the behaviour of various grades of high and low density polyethylene subjected to continuous injection moulding operations. It is based on a wide range of experimental techniques that allowed the establishment of relationships between the observed property changes and the structural modifications developed in the polymers. The study confirmed the coexistence of two distinct degradation mechanisms, crosslinking and chain scission, that occur due to thermo-oxidative reactions arising during the different injection moulding stages. The relative importance of these two mechanisms depends on the material structure and on the processing conditions used. It was also possible to confirm that the polyethylenes with lower molecular mass show low sensitivity to degradation during reprocessing. Furthermore, the more branched polymers (as is the case of LDPE) also proved to be less sensitive to thermo-degradation phenomena. Overall, it was concluded that the primary recycling of polyethylene, if performed under well controlled conditions, will lead to only minor material property losses.
A.A. Mendes, A.M. Cunha, C.A. Bernardo, Polymer Degradation and Stability 96 (2011) 1125-1133

B3149 – Experimental study of uranium carbide pyrophoricity

Mixed plutonium and uranium monocarbide (UPuC) is considered as a possible fuel material for future nuclear gas fast reactors. Its safe handling is currently a major concern, because inflammation of this material under the shape of fine powders is easy and highly exothermic (pyrophoricity) even under ambient temperature and partial pressure of oxygen inferior to 0.2 bar. CEA Marcoule is implied in both experimental and numerical studies on the UC powder oxidation exothermic reaction. Experimental tests consist in determining the influence of various parameters (gas composition, heating ramp, specific surface of powders) on the sample inflammation temperature. Two kinds of analytical apparatus are used: The differential thermal analysis (DTA) and the differential scanning calorimetry (DSC) coupled to the thermo gravimetric analysis (TGA). These apparatus are also linked to a gas mass spectrometer to follow the composition of combustion chamber gases. Results obtained with small quantities revealed that UC powder is highly reactive in air in the temperature range of 150–250 °C and showed a strong dependence between powder height in crucibles and inflammation temperature.
C. Berthinier, S. Coullomb, C. Rado, E. Blanquet, R. Boichot, C. Chatillon, Powder Technology 208 (2011) 312–317

B3159 – Investigations of a mechanically failed cable insulation used in indoor conditions

This paper presents the investigation work on different polymeric materials used as insulation materials of conductors in a multicore instrumentation cable. Among differently colored materials, only the white one presented cracks after a few years of use. Isothermal and non-isothermal DSC measurements were performed on initial (non-used) and aged (in service used or laboratory aged) materials as well as on raw materials in order to characterize their stability and the ageing state after storage, use in service or laboratory ageing. As shown by the oxidation induction time values, a pronounced antioxidant loss occurred for all materials during storage or service; plus a strong effect of the ambient light on stability was observed for the white insulation material. Around 3% of filler, consisting mainly of TiO2 particles (as revealed by SEM-XRF elemental analysis), was found in the white material. The higher degradability of the white material can be related to both the photocatalytic effect of the TiO2 particles and rapid loss of stabilizers.
S. Ilie, R. Setnescu, E.M. Lungulescu, V. Marinescu, D. Ilie, T. Setnescu, G. Mares, Polymer Testing 30 (2011) 173–182

B3148 – Physicochemical properties of Cs borosilicate glasses containing CaO

A series of Cs-borosilicate glasses of general formula (mol%): 17.5Na2O–2.5Cs2O–45SiO2–(35-x)B2O3–xCaO, where x varies from 0 to 10, were prepared by conventional melt quenching technique. Physicochemical properties like glass transition temperature, extent of volatilization loss of Cs and chemical durability of these glasses have been investigated in detail. Based on the Tg values obtained from DSC studies, it is confirmed that the glass network remains unaffected with increase in CaO content in the glass at the expense of B2O3. Cs loss as function of duration of heating revealed that the Cs evaporation follows diffusion controlled mechanism and the extent of loss increases with the increase of CaO incorporation in glass. Chemical durability of the glasses has been found to improve significantly with in the increase of CaO content in glass and this has been attributed to the formation of Ca and Si rich layer at the outer surface of the glass, as inferred from SEM with EDX analysis.
D. Banerjee, V. Sudarsan, A. Joseph, I.J. Singh, J. Nuwad, C.G.S. Pillai, P.K. Watta, D. Das, Journal of Nuclear Materials 413 (2011) 177–182

B3158 – Permeation and sorption properties of poly(ether-block-amide) membranes filled by two types of zeolites

The experimental study of transport properties of mixed matrix membranes (MMMs) based on PEBA-4033 with two types of zeolites is reported. Gas (CO2, O2, N2) and vapor (benzene, toluene, methanol, water) permeation measurements were performed using the differential flow permeameter at temperature of 298.15 K and at atmospheric pressure. Gas/vapor permeation was monitored by measuring the changes of the thermal conductivity of carrier gas (H2). Sorption experiments were performed gravimetrically. Determined values of the transport parameters (permeability, diffusion and sorption coefficients) of all studied vapors revealed expected high-order permeability of PEBA based membranes for vapors in comparison with gases whereas increasing of zeolite-filler content up to 30 wt.% in polymer matrix led to higher values of permeability and gas/gas and vapor/gas selectivity in comparison with pure polymer.
Karel Friess, Vladimír Hynek, Milan Šípek, Wojciech M. Kujawski, Ondrej Vopicka, Miroslav Zgazar, Maciej W. Kujawski, Separation and Purification Technology 80 (2011) 418–427

B3147 – Annealing temperature effect on the properties of mercury-doped TiO2 films prepared by sol–gel dip-coating technique

This work presents the annealing temperature effect on the properties of mercury (Hg)-doped titanium dioxide (TiO2). Thin films and polycrystalline powders have been prepared by sol–gel process. The structure, surface morphology and optical properties, as a function of the annealing temperature, have been studied by atomic force microscopy (AFM), Raman, reflectance and ellipsometric spectroscopies. In order to determine the transformation points, we have analyzed the xerogel-obtained powder by differential scanning calorimetry (DSC). Raman spectroscopy shows the crystalline anatase and rutile phases for the films annealed at 400 °C and 1000 °C respectively. The AFM surface morphology results indicate that the particle size increases from 14 to 57 nm by increasing the annealing temperature. The complex index and the optical band gap (Eg) of the films were determined by the spectroscopic ellipsometry analysis. We have found that the optical band gap decreases by increasing the annealing temperature.
R. Mechiakh, N. Ben Sedrine, M. Karyaoui, R. Chtourou, Applied Surface Science 257 (2011) 5529–5534

B3157 – Internal friction, dilatometric and calorimetric study of anelasticity in Fe–13 at.%Ga and Fe–8 at.% Al–3 at.% Ga alloys

This paper investigates the structural transitions associated with different cooling rates from a high temperature disordered state and the effect of substitution of Ga atoms by Al atoms in Fe–Ga binary alloys on the ordering processes. Two iron-based low carbon (about 0.04 at.% C) alloys Fe–13 at.% Ga and Fe–8 at.% Al–3 at.% Ga are studied. Internal friction, dilatometric and calorimetric tests are carried out to check ordering in these alloys and contribution of structural defects to relaxation spectrum. Several thermally activated internal friction peaks have been observed and their activation parameters evaluated by means of temperature and frequency dependent internal friction tests using forced vibration. For most of these peaks physical mechanisms are proposed. Apart from these thermally activated relaxation peaks, a structural, frequency independent relaxation takes place at 250–300 °C. Dilatometric and DSC curves show the appearance of a contraction effect in the same temperature range. This effect was studied in alloys cooled down with different cooling rates. We believe that the frequency independent internal friction peak (denoted as the P3 peak in this paper) and peaks at dilatometric and DSC curves are controlled by the same structural mechanism and therefore the activation energy for this anelastic mechanism is derived from DSC data.
I.S. Golovin, Z. Belamri, D. Hamana, Journal of Alloys and Compounds 509 (2011) 8165– 8170

B3156 – Simultaneous preferential crystallization in a coupled batch operation mode. Part II:Experimental study and model refinement

In the previous part of this series a parametric study was presented to assess theoretically the performance of a novel crystallizer configuration. Complementary, the present work addresses a comprehensive, systematic experimental examination accompanied by an analysis of some relevant process parameters (mass of seeds, CSD of seeds, starting point for the mother liquor exchange, process duration) of two general concepts for preferential crystallization in which the amino acid threonine dissolved in water was used as a model system. In the first step of investigations, the impact of these process parameters was studied for conventional single batch crystallization. The experimental results are discussed and compared with the theoretical ones. Moreover, a configuration consisting of two coupled crystallization vessels was investigated. The specific manipulation of the concentration profiles of each enantiomer in solution as well as of the temperature profiles was found to be suitable to enhance the process performance. This is reflected by higher achievable process productivities and higher product purities.
Martin Peter Elsner, Grzegorz Ziomek, Andreas Seidel-Morgenstern, Chemical Engineering Science 66 (2011) 1269–1284

B3155 – Microstructure and magnetocaloric effects in partially amorphous Gd55Co15Al30?xSix alloys

In order to clarify the phase components and further improve the glass-forming ability of Gd55Co15Al30 alloy, substitution of Al with Si was adopted. Although the X-ray powder diffraction experiment indicated an amorphous structure of the Gd55Co15Al30-xSix (x = 1, 2, 3) alloys, precipitation of crystalline Gd2Al phase was evident from the energy-dispersive spectroscopy, selected-area diffraction, and magnetization measurements. The magnetocaloric effect of Si substituted alloys is lower than that of Gd52.5Co16.5Al31 alloy with a similar composition and full amorphous structure, which is ascribed to the presence of antiferromagnetic Gd2Al phase whose magnetic entropy change is lower
H. Fu, M. Zou, Q. Cao, V.K. Pecharsky, K.A. Gschneidner Jr, L.S. Chumbley, Materials Science and Engineering A 528 (2011) 5219–5222

B3154 – Designing an extended release waxy matrix tablet containing nicardipine–hydroxy propyl ? cyclodextrin complex

The current study aimed to prepare a sustained release tablet for a drug which has poor solubility in alkaline medium using complexation with cyclodextrin. Nicardipine hydrochloride (NC) a weak basic drug was chosen as a model drug for this study.
Hind Al-Zein, Khalil Sakeer, Fars K. Alanazi, Saudi Pharmaceutical Journal (2011) 19, 245–253

B3153 – Solidification behavior, glass forming ability and thermal characteristics of soft magnetic Fe-Co-B-Si-Nb-Cu bulk amorphous alloys

The effect of varying Cu content on the bulk glass forming ability (GFA) of (Fe0.36Co0.36B0.192Si0.048Nb0.04)100?XCuX alloys (X = 0, 0.5, 0.75 and 1.0) is revealed by investigating the thermal behaviors and phase competitions upon solidification. The changes in GFA are interpreted in terms of suppression of consecutive solidification reactions via microstructural and thermal features. Instead of the type of the primary crystallization product originating from the prevalent atomic order in the glass or supercooled liquid, precipitation of faceted binary and higher-order pro-eutectic compounds such as (Fe,Co)2B and (Fe,Co)NbB from the alloy melt and resulting skewed eutectic coupled zone are correlated with the observed GFA. With the employed centrifugal casting method, the (Fe0.36Co0.36B0.192Si0.048Nb0.04)99.25Cu0.75 alloy shows the largest critical thickness of 3 mm and the best soft magnetic properties such as 1.58 T saturation magnetization intensity and 11.7 A/m coercivity after annealing.
Muratahan Aykol, M. Vedat Akdeniz, Amdulla O. Mekhrabov, Intermetallics 19 (2011) 1330-1337

B3152 – The Lu–Ru–O System: Thermodynamic properties and impedance measurements of the pyrochlore Lu2Ru2O7(s)

The Gibbs free energy of formation of Lu2Ru2O7(s) has been determined using solid-state electrochemical technique employing oxide ion conducting electrolyte. The reversible electromotive force (e.m.f.) of the following solid-state electrochemical cell has been measured: Cell:(?)Pt/{Lu2O3(s)+Lu2Ru2O7(s)+Ru(s)}//CSZ//O2(p(O2)=21.21 kPa)/Pt(+)Cell:(?)Pt/Lu2O3s+Lu2Ru2O7s+Rus//CSZ//O2pO2=21.21 kPa/Pt+ The Gibbs free energy of formation of Lu2Ru2O7(s) from elements in their standard state, calculated by the least squares regression analysis of the data obtained in the present study, can be represented by: {f?G°(Lu2Ru2O7,s)/(kJ·mol?1)±2.7}=?2513.7+0.6265·(T/K);943.9£T/K£1230).{?fG°Lu2Ru2O7,s/kJ·mol?1±2.7}=?2513.7+0.6265·T/K;943.9£T/K£1230). Standard molar heat capacity C°p,m(T) of Lu2Ru2O7(s), was measured using a heat flux type differential scanning calorimeter (DSC) in two different temperature ranges, from 127 K to 299 K and 307 K to 845 K. The heat capacity in the higher temperature range was fitted into a polynomial expression and can be represented by: C°p,m(Lu2Ru2O7(s)(J.K?1·mol?1)=294.535+2.0·10?4T(K)?49.00688·105/T2(K).C°p,m(Lu2Ru2O7sJ.K?1·mol?1=294.535+2.0·10?4TK?49.00688·105/T2K. The second law method gave the value of standard enthalpy of formation and entropy, of the compound from elements at 298.15 K. An oxygen potential diagram for the Lu–Ru–O system was computed based on the thermodynamic data obtained. Impedance measurements on Lu2Ru2O7(s), suggests a semiconductor like behavior with low activation energy.
Aparna Banerjee, R. Mishra, Ziley Singh, Solid State Ionics 201 (2011) 42–48

B3151 – Antifouling performance of poly(acrylonitrile)-based membranes: From green synthesis to application

In order to develop clean ultrafiltration membranes able to prevent the fouling of biological compounds in filtration processes, poly(ethylene glycol) methyl ether acrylate (PEGA) was grafted to poly(acrylonitrile) (PAN) by free-radical polymerization in supercritical carbon dioxide (scCO2) and the grafted copolymer was blended with PAN to fabricate porous membranes using scCO2-induced phase inversion method. Fourier transform infrared (FT-IR) analysis, 1H nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC) confirmed that the poly(acrylonitrile)-graft-poly(ethylene oxide) (PAN-g-PEO) was successfully synthesized, for the first time, in scCO2. The effect of increasing PEGA content on the initial monomer feed mixture on graft polymer morphology and average molecular weight was studied. Blended membranes with different PEGA contents were investigated by scanning electron microscopy (SEM), mercury porosimetry and dynamical mechanical analysis (DMA) to characterize their morphological, physico-chemical and mechanical properties. Moreover, water contact angle measurements, pure water permeability and filtration experiments were performed to evaluate membrane hydrophilicity and fouling resistance properties. Permeation experiments of model foulants, bovine serum albumin (BSA) and starch solutions were used to investigate antifouling character of blend membranes at different pHs. PAN:PAN-g-PEO (70:30) showed to be the ultrafiltration membrane with best performance. Furthermore, comparing with conventional technologies blended membranes of PAN:PAN-g-PEO prepared by a scCO2-assisted process showed enhanced hydrophilicity, larger protein and starch solution permeabilities and good resistance to irreversible fouling, indicating that the technology is an efficient process to prepare fouling resistant membranes for biomacromolecule separations.
Telma Barroso, Márcio Temtem, Teresa Casimiro, Ana Aguiar-Ricardo, J. of Supercritical Fluids 56 (2011) 312–321

B3172 – Effect of annealing treatment on microstructure and properties of high-entropy FeCoNiCrCu0.5 alloy

As-cast FeCoNiCuAl high entropy alloys were annealed at various temperatures for a given time. The microstructure and mechanical properties of the annealed FeCoNiCuAl high entropy alloys were investigated using optical microscopy, scanning electron microscopy, X-ray diffraction, compressive and hardness tests. It has been found that the FeCoNiCuAl has high thermal stability. A needle-like Cu-rich FCC phase has been precipitated from the BCC dendrite region when the annealing temperature is higher than 973 K. The higher temperature treatment greatly enhances the plasticity of the alloys, and reduces the hardness of the alloys. The annealing induced change in microstructure and properties could be attributed to a solid phase transformation, which consists of the dissolution of the FCC interdendrite phase into the matrix and the concomitant precipitation of the needle-like shape FCC phase from dendrite region.
Chun-Ming Lin, Hsien-Lung Tsai, Materials Chemistry and Physics 128 (2011) 50–56

B3161 – The effect of Si content on the martensitic transformation temperature of Ni55:5Fe18Ga26.5-xSix alloys

This paper investigates the effects of substitution of Si for Ga on the martensitic transformation behaviours in Ni-Fe-Ga alloys by using optical metallographic microscope and differential scanning calorimetry (DSC) methods. The structure type of Ni55.5Fe18Ga26.5?xSix alloys is determined by x-ray diffraction (XRD), and the XRD patterns show the microstructure of Ni—Fe—Ga—Si alloys transformed from body-centred tetragonal martensite (with Si content x = 0) to body-centred cubic austenite (with x = 2) at room temperature. The martensitic transformation temperatures of the Ni55.5Fe18Ga26.5?xSix alloys decrease almost linearly with increasing Si content in the Si content range of x ? 3. Thermal treatment also plays an important role on martensitic transformation temperatures in the Ni-Fe-Ga-Si alloy. The valence electronic concentrations, size factor, L21 degree of order and strength of parent phase influence the martensitic transformation temperatures of the Ni-Fe-Ga-Si alloys. An understanding of the relationship between martensitic transformation temperatures and Si content will be significant for designing an appropriate Ni-Fe-Ga-Si alloy for a specific application at a given temperature.
Shen Hua-Hai, Yu Hua-Jun, Fu Hao, Guo Yuan-Jun, Fu Yong-Qing, Zu Xiao-Tao, Chin. Phys. B Vol. 20, No. 4 (2011) 046102

B3171 – The role of heat treatment on microstructure and mechanical properties of Ti–13Zr–13Nb alloy for biomedical load bearing applications

The effect of heat treatment on microstructure and mechanical properties of a ferritic heat-resistant steel, 2.25Cr–1Mo, was investigated. The characteristics of carbides, i.e., size, morphology, distribution, and composition, in different stages of heat treatment were examined by using transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). As the heat treatment proceeded from normalizing and tempering (NT, the delivery state), simulated post-welding heat treatment (PWHT), to step cooling (SC), the carbides evolved from M3C, Mo2C to M7C3, M23C6. The uniformly dispersed carbides, e.g., Mo2C, M7C3, and M23C6, are responsible for the excellent mechanical properties and creep resistance of the steel. The result demonstrates that the coarsening of carbides deteriorates impact toughness and the morphology, crystal structure, and chemical composition of carbides are also important influencing factors.
P. Majumdar, S.B. Singh, M. Chakraborty, Journal of the Mechanical Behavior of Biomedical Materials 4 (2011) 1132-1144

B3170 – Experimental characterization of plastic flow initiation in a bulk metallic glass via intermittent compression test

Intermittently plastic compression tests of the Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass were performed under a geometrically constrained condition at different cross-head displacement rates. A flow stress-overshoot phenomenon was observed during the macroscopically plastic deformation. It was found that there is a close correlation between the stress-overshoot intensity and the spatial density of shear bands. The stress-overshoot intensity can be used as a parameter to characterize the ability of plastic flow initiation caused by the spatial nucleation of shear bands in the bulk metallic glass. The micromechanisms of shear band multiplication were discussed.
Z.H. Han, X.P. Li, L. He, W. Chen, F. Jiang, J. Sun, Intermetallics 19 (2011) 942-946

B3169 – Cu22Bi12S21Cl16—A mixed conductor with fast one-dimensional copper(I) ion transport

Melting reactions of Cu, CuCl, S, and Bi2S3 yield black, shiny needles of Cu22(1)Bi12S21(1)Cl16(1). The compound decomposes peritectically at 649(5) K. Oxidation state +I of the copper atoms is supported by Cu–K-XANES. The compound crystallizes in the hexagonal space group P6/m with a=2116.7(7) pm and c=395.17(5) pm. Seven anions coordinate each of the two independent bismuth cations in the shape of mono-capped trigonal prisms. These polyhedra share edges and faces to form trigonal and hexagonal tubes running along [0 0 1]. The hexagonal tubes are centered by chloride ions, which are surrounded by disordered copper cations. The majority of copper cations are distributed over numerous sites between the tubes. The Joint Probability Density Function (JPDF) reveals a continuous pathway along [0 0 1]. The high mobility of the copper cations along [0 0 1] was demonstrated by impedance spectroscopy and DC polarization measurements on single crystals. The ionic conductivity at 450 K is about ?ion=0.06 S cm?1, and the activation energy for Cu+ ion conduction is Ea=0.44 eV. The chemical diffusion coefficient of copper is in the order of Dcu?=1019 cm?3 at 420 K. The electronic band gap (p-type conductor) was determined as Eg=0.06 eV. At room temperature the thermal conductivity of a pressed pellet is about ?=0.3 W K?1 m?1 and the Seebeck coefficient is S=43 ?V K?1.
Andreas Heerwig, Rotraut Merkle, Joachim Maier, Michael Ruck, Journal of Solid State Chemistry 184 (2011) 191–198

B3168 – Large SiO2-substituted GeO2 single-crystals with the ?-quartz structure

Colorless, transparent SiO2-substituted GeO2 single-crystals with the ?-quartz-like structure have been grown by spontaneous nucleation using the slow-cooling method from K2O–3MoO3 flux. The cell parameter values as well as the semi-quantitative chemical analyses confirm the presence of Si-content in the as-grown crystals. Their thermal behavior was studied by means of differential scanning calorimetry and high-temperature X-ray diffraction. The high stability of the ?-quartz-like structure as a function of temperature was confirmed up to 1000 °C. The structural parameter data have been used to estimate the lattice and volume thermal expansion coefficients from room temperature up to 1000 °C.
Pascale Armand, Simon Clément, Denis Balitsky, Adrien Lignie, Philippe Papet, Journal of Crystal Growth 316 (2011) 153–157

B3167 – Effect of cooling rate on solidification of Al-Ni alloys

Particles of Al-Ni alloys with different compositions (Al–50 wt-% Ni and Al–36 wt-% Ni) were produced using a drop tube-impulse system, known as Impulse Atomization. The microstructure of these rapidly solidified particles was compared with those solidified in a DSC at low cooling rates (0.083 and 0.33 K/sec). Also, the microstructure of the sample solidified in microgravity on-board of the TEXUS 44 sounding rocket was analyzed. Neutron diffraction was used to investigate the phases formed during different solidification processes. From SEM micrographs and neutron diffraction it was found that the inner parts of the TEXUS sample and the sample that was cooled at 0.083 K/sec contain almost no eutectic structure. The outer rim of the TEXUS sample showed the highest amount of Al3Ni and lowest amount of Al3Ni2 Increasing the cooling rate from 0.083 to 0.33 K/sec increased the Al3Ni/Al3Ni2 ratio. Opposite trend was observed in the impulse-atomized particles, where increasing the cooling rate decreased the Al3Ni/Al3Ni2 ratio.
A. Ilbagi, P. Delshad Khatibi, H. Henein, R. Lengsdorf, D. M. Herlach, Journal of Physics: Conference Series 327 (2011) 012010

B3166 – Optimization of composition and heat treatment design of Mg–Sn–Zn alloys via the CALPHAD method

This work is focused on the application of the calculation of phase diagrams method for alloy and heat treatment design. We analyzed the influence of Zn content on the precipitation of Mg2Sn in Mg–Sn–Zn alloys. A comparison with previous studies in the Mg–Sn–Zn system was made according to the published results and computational thermochemistry simulations. The phase evolution in the Mg–Sn–Zn system was evaluated for the different compositions, and the simulations were used for precise alloy and heat treatment design. The composition of the ternary alloy was set as Mg–8wt%Sn–1.25wt%Zn. The Sn and Zn content was designed and confirmed to be within the ?-Mg solubility limit at the solution treatment temperature. The addition of Zn and the heat treatment applied resulted in the enhancement and refinement of the Mg2Sn precipitation. Three Vickers micro-hardness maxima were detected: precipitation of metastable Mg–Zn phases, heterogeneous precipitation of Mg2Sn on the Mg–Zn precipitates, and Mg2Sn precipitation in the ?-Mg matrix. The CT simulations were found to be a valuable alloy design tool.
S. Avraham, A. Katsman, M. Bamberger, J Mater Sci (2011) 46:6941–6951

B3165 – Aging and thermal expansion behavior of Si3N4p/2024Al composite fabricated by pressure infiltration method

The aging and thermal expansion behaviors of Si3N4p/2024Al composite fabricated by pressure infiltration method were investigated. The peak-aging time and peak hardness both decrease with the increase of aging temperature for both the 2024Al alloy and Si3N4p/2024Al composite. The calculated activation energies of s? (precursors of the Al2MgCu) phase indicate that the precipitation of s? phase in Si3N4p/2024Al composite occurs easily than in 2024Al alloy. The presence of Si3N4 particles does not alter precipitation sequence, but accelerates the process of aging precipitation in Si3N4p/2024Al composite. The experimental coefficient of thermal expansion (CTE) of Si3N4p/2024Al composite bellow 100°C is more close to the average value of the Kerner model (upper bound Schapery model) and lower bound Schapery model. Aging treated Si3N4p/2024Al composite presents the best dimensional stability due to low internal stress and strong pining effect on dislocations from fine dispersed precipitates (Al2MgCu) and high density tangled dislocations. The good mechanical properties, compatible CTE with steel and high dimensional stability make Si3N4p/2024Al composite very competitive for application in the inertial guidance field.
Chen Guo-qing, Yang Wen-shu, Ma Kang, Murid Hussain, Jiang Long-tao, Wu Gao-hui, Transactions of Nonferrous Metals Society of China, Volume 21, Supplement 2, August 2011, Pages s262–s273

B3164 – Characteristics, chemical composition and utilisation of Albizia julibrissin seed oil

The physicochemical characteristics, fatty acid and triacylglycerol compositions, DSC profile and UV/vis spectrum of oil extracted from Albizia julibrissin seeds were determined in this study. The oil content and the moisture of the seeds were 10.50% and 1.56%. The free fatty acid, the peroxide value, the p-anisidine value, the saponification value, the iodine value were 2.54%, 6.61 mequiv. O2/kg of oil, 1.98, 190.63 (mg KOH/g) and 111.33 (g/100 g of oil), respectively. The specific extinction coefficients K232, K268 were 7.55 and 0.96, respectively. Linoleic acid (C18:2, 58.58%), palmitic acid (C16, 13.86%) and oleic acid (C18:1, 10.47%) were the dominant fatty acids in the A. julibrissin seed oil. LLL (36.87%), OLL (21.62%), PLL (16.69%) and PLO + SLL (8.59%) were the abundant triacylglycerol representing > 83% of the seed oil (L: linoleic, O: oleic, P: palmitic, S: stearic). The DSC melting curves reveal that: melting point = ?14.70° C and melting enthalpy = 54.34 J/g. A. julibrissin seed oil showed some absorbance in the UV-B and UV-C ranges. The results of the present analytical study show that A. julibrissin is a promising oilseed crop, which can be used for making soap, hair shampoo and UV protectors. Furthermore, the high level of unsaturated fatty acids makes it desirable in terms of nutrition.
I. Nehdi, Industrial Crops and Products 33 (2011) 30–34

B3174 – Effect of 1 wt% LiF additive on the densification of nanocrystalline Y2O3 ceramics by spark plasma sintering

Densification of nanocrystalline cubic yttria (nc-Y2O3) powder, with 18 nm crystal size and 1 wt% LiF as a sintering additive was investigated. Specimens were fabricated by spark plasma sintering at 100 MPa, within the temperature range of 700–1500 °C. Sintering at 700 °C for 5 and 20 min resulted in 95% and 99.7% dense specimens, with an average grain size of 84 and 130 nm, respectively. nc-Y2O3 without additive was only 65% dense at 700 °C for 5 min. The presence of LiF at low sintering temperatures facilitated rapid densification by particle sliding and jamming release. Sintering at high temperatures resulted in segregation of LiF to the grain boundaries and its entrapment as globular phase within the fast growing Y2O3 grains. The sintering enhancement advantage of LiF was lost at high SPS temperatures.
Rachel Marder, Rachman Chaim, Geoffroy Chevallier, Claude Estournès, Journal of the European Ceramic Society 31 (2011) 1057–1066

B3163 – Changes in chemical composition of Phoenix canariensis Hort. Ex Chabaud palm seed oil during the ripening process

The aim of this investigation is to compare the physicochemical properties and chemical composition of Phoenix canariensis seed oil at different stages of seed date ripening. It was demonstrated that the saponification number of the oil increases during the maturation from 179.24 to 191.28 (mg KOH/g of oil), whereas the seed oil yield, the iodine number, the p-anisidine value, the peroxide value, the acidity and the unsaponifiable matter decrease from 14.73% to 10.36%, from 89.37 to 76.66 (g/100 g of oil), from 5.51 to 3.67, from 17.66 to 3.62 (mequiv. O2/kg of oil), from 1.49% to 0.59% and from 2.72% to 1.77%, respectively. The tocol content increases as the maturity advanced. The percentages of sterols show continuous changes during ripening. The saturated fatty acid content increases throughout the ripening process. The oleic fatty acid content decreases during the seeds maturation, but increases at the end, whereas linoleic acid content initially shows an increase, and then a decrease. The total phosphorus content decreases during the period of ripening. The three samples of the seed oil show a high kinetic stability during the heating and cooling, as characterised by the differential scanning calorimetry (DSC). The DSC curves reveal an increase in the melting point from ?7.73 °C to 3.71 °C but the melting enthalpy remains the same, 62.06 J/g, during the ripening of the dates.
Imededdine Arbi Nehdi, Hedi Zarrouk, Saud Ibrahim Al-Resayes, Scientia Horticulturae 129 (2011) 724–729

B3173 – Densification and polymorphic transition of multiphase Y2O3 nanoparticles during spark plasma sintering

Multiphase (MP) monoclinic and cubic Y2O3 nanoparticles, 40 nm in diameter, were densified by spark plasma sintering for 5–15 min and100 MPa at 1000 °C, 1100 °C, and 1500 °C. Densification started with pressure increase at room temperature. Densification stagnated during heating compared to the high shrinkage rate in cubic single-phase reference nanopowder. The limited densification of the MP nanopowder originated from the vermicular structure (skeleton) formed during the heating. Interface controlled monoclinic to cubic polymorphic transformation above 980 °C led to the formation of large spherical cubic grains within the vermicular matrix. This resulted in the loss of the nanocrystalline character and low final density.
R. Marder, R. Chaim, G. Chevallier, C. Estournes, Materials Science and Engineering A 528 (2011) 7200– 7206

B3162 – Characteristics and composition of Washingtonia filifera (Linden ex André) H. Wendl. seed and seed oil

Characteristics of seeds and oil extracted from Washingtonia filifera seeds are evaluated. The percentage composition of the W. filifera seeds is: ash 1.37%, oil 16.30%, protein content 3.46%, total carbohydrate 77.19% and moisture 3.22%. The major nutrients (mg/100 g of seeds) found in the seeds are: potassium (67.33), magnesium (34.35), calcium (187.85) and phosphorus (23.26). Physicochemical properties of the oil include: iodine value 67.33 g/100 g of oil; saponification value, 191.63 mg KOH/g of oil; refractive index (25 °C), 1.469; unsaponifiable matter, 0.83%; acidity, 0.41%; p-anisidine value, 0.87; peroxide value, 7.60 mEq O2/kg of oil; carotenoid content 14.8 mg/100 g and the chlorophyll content = 0.13 mg/100 g. W. filifera seed oil shows some absorbance in the UV-B and UV-C ranges with potential use as a broad spectrum UV protectant. The oil contains high levels of oleic acid (40.60%) followed by lauric acid (17.87%), linoleic acid (16.26%), myristic acid (11.43%) and palmitic acid (9.23%). The triacylglycerols (TAGs) with equivalent carbon number ECN 44 (20.47%) are dominant, followed by TAGs ECN 46 (16.71%), TAGs ECN 42 (15.43%) and TAGs ECN 48 (15.41%). The DSC melting curves reveal that: melting point = 2.25 °C and melting enthalpy = 82.34 J/g. ?-Tocotrienol is the major tocol (72%) with the rest being ?-tocotrienol and ?-tocotrienol. The results of the present analytical study show that W. filifera seed oil could be used in cosmetic, pharmaceutical and food products.
Imededdine Arbi Nehdi, Food Chemistry 126 (2011) 197–202

B3182 – Preparation and characterization of nanocomposite, silica aerogel, activated carbon and its adsorption properties for Cd (II) ions from aqueous solution

A novel composite adsorbent, silica aerogel activated carbon was synthesized by sol-gel process at ambient pressure drying method. The composite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Nitrogen adsorption/desorption isotherms (BET). In the present study, the mentioned adsorbent was used moderately for the removal of cadmium ions from aqueous solutions and was compared with two other adsorbents of cadmium, activated carbon and silica aerogel. The experiments of Cd adsorption by adsorbents were performed at different initial ion concentrations, pH of the solution, adsorption temperature, adsorbent dosage and contact time. Moreover, the optimum pH for the adsorption was found to be 6.0 with the corresponding adsorbent dosage level of 0.1 g at 60 C temperature. Subsequently, the equilibrium was achieved for Cd with 120 min of contact time.
M.H. Givianrad, M. Rabani, M. Saber-Tehrani, P. Aberoomand-Azar, M. Hosseini Sabzevari, Journal of Saudi Chemical Society (2013) 17, 329–335

B3181 – Rapid solidification and phase stability evaluation of Ti–Si–B alloys

Ti-rich Ti–Si–B alloys can be considered for structural applications at high temperatures (max. 700 °C), however, phase equilibria data is reported only for T = 1250 °C. Thus, in this work the phase stability of this system has been evaluated at 700 °C. In order to attain equilibrium conditions in shorter time, rapid solidified samples have been prepared and carefully characterized. The microstructural characterization of the produced materials were based on X-ray diffraction (XRD), scanning electron microscopy (SEM-BSE), high resolution transmission electron microscopy (HRTEM), High Temperature X-ray diffraction with Synchrotron radiation (XRDSR) and Differential Scanning Calorimetry (DSC). Amorphous and amorphous with embedded nanocrystals have been observed after rapid solidification from specific alloy compositions. The values of the crystallization temperature (Tx) of the alloys were in the 509–647 °C temperature range. After Differential Scanning Calorimetry and High Temperature X-ray Diffraction with Synchrotron radiation, the alloys showed crystalline and basically formed by two or three of the following phases: ?Ti, Ti6Si2B; Ti5Si3; Ti3Si and TiB. It has been shown the stability of the Ti3Si and Ti6Si2B phases at 700 °C and the proposition of an isothermal section at this temperature.
K.C.G. Candioto, C.A. Nunes, G.C. Coelho, P.A. Suzuki, S.B. Gabriel, Journal of Alloys and Compounds 509 (2011) 5263–5268

B3180 – Fe–Al phase formation around SHS reactions under isothermal conditions

This study investigates the phenomena preceding and accompanying the SHS reaction between Fe and Al elemental powders during sintering. SEM and XRD analysis were used to observe the mechanisms of formation of Fe–Al intermetallic phases. The analysis of sintered material just before the SHS reaction demonstrates that in addition to the well-known Fe2Al5 phase and the low-aluminum solid solution of iron, the high-aluminum phases FeAl2 and FeAl3 are formed. The kinetics of phase transformations under isothermal conditions were investigated by DSC using the JMA (Johnson–Mehl–Avrami) model. This approach allowed us to calculate Avrami coefficients, which characterize the speed and the manner of particular phase transformations.
Ewelina Pochec, Stanis?aw Józwiak, Krzysztof Karczewski, Zbigniew Bojar, Journal of Alloys and Compounds 509 (2011) 1124–1128

B3179 – High-temperature thermal and X-ray diffraction studies, and room-temperature spectroscopic investigation of some inorganic pigments

Inorganic Cr- and Mn-containing pigments of different structural types were investigated by high-temperature and spectroscopic methods. The differential scanning calorimetry in the temperature interval 298–1723 K was applied to measure temperatures of phase transition and melting of the studied compounds. High-temperature X-ray diffraction in the range 298–1173 K was used for the determination of the thermal expansion coefficients for the first time. Factor group analysis was used to predict general vibration modes of pigments and determine the activity of these vibrations in Raman and IR spectra, the Assignment of bands in Raman, IR and diffuse reflectance spectra was undertaken
A.V. Knyazev, M. Maczka, E.N. Bulanov, M. Ptak, S.S. Belopolskaya, Dyes and Pigments 91 (2011) 286-293

B3178 – Shear transformation zone volume determining ductile–brittle transition of bulk metallic glasses

Three-point bending experiments were performed on as-cast and annealed samples of Zr52.5Cu17.9Ni14.6Al10Ti5 (Vit105) bulk metallic glasses over a wide range of temperatures varying from room temperature (293 K) to liquid nitrogen temperature (77 K). The results demonstrated that the free volume decrease due to annealing and/or cryogenic temperature can reduce the propensity for the formation of multiple shear bands and hence deteriorate plastic deformation ability. We clearly observed a sharp ductile-to-brittle transition (DBT), across which microscopic fracture feature transfers from micro-scale vein patterns to nano-scale periodic corrugations. Macroscopically, the corresponding fracture mode changes from ductile shear fracture to brittle tensile fracture. The shear transformation zone volume, taking into account free volume, temperature and strain rate, is proposed to quantitatively characterize the DBT behavior in fracture of metallic glasses.
F. Jiang, M.Q. Jiang, H.F. Wang, Y.L. Zhao, L. He, J. Sun, Acta Materialia 59 (2011) 2057–2068

B3177 – High-temperature X-ray analysis of phase evolution in Sr-doped zinc-silicate glasses

Bone grafts are required in many clinical situations. Autografts are the traditional gold standard for treating conditions requiring bone grafts. However autografts have inherent drawbacks such as donor site morbidity, pain and increased operative time. An alternative for autografts are synthetic grafts. A series of strontium doped zinc silicate glasses were developed which were investigated using high temperature X-ray diffraction (HT-XRD) in order to establish phase transformations, which occur up to the first crystallization temperature, (Tp1), thus identifying the composition–structure relationships which arise during this thermal processing. In analysing BT110 it was observed that all glass material crystallised into 4 phases including strontium zinc silicate, sodium calcium silicate, calcium silicate and strontium silicate, leaving no residual glass phase. BT111 and BT112 were shown to contain a residual glassy phase alongside for BT111, sodium zinc silicate, larnite and silicon oxide and for BT112 strontium silicate, calcium silicate, sodium silicate and silicon oxide. In the case of BT111 the residual glass phase appears to be rich in strontium. The residual glass phase being Sr enriched with respect to the glass-ceramic may offer increased release of Sr2+ from the material; important for the regulation of osteoblastic and osteoclastic activity. BT113 crystallized to form strontium silicate, sodium silicate, and strontium zinc silicate. BT114 crystallized to form strontium silicate and sodium silicate. The biocompatibility of phases formed in BT113 and BT114 is as yet unknown. Further knowledge will be generated by later work examining the biocompatibility of these phases identified in this research. However, on the basis of these results, the materials (BT110–BT112) exhibit potential as a bone graft substitutes, whilst BT113–BT114 give rise to phases with unknown biocompatibility and so warrant further investigation.
Mark Looney, Helen O'Shea, Wynette Redington, Gerard Kelly, D. Boyd, Journal of Non-Crystalline Solids 357 (2011) 2097–2102

B3176 – Sol–gel synthesis of a new composition of bioactive glass in the quaternary system SiO2–CaO–Na2O–P2O5. Comparison with melting method

New sol–gel experimental conditions were tested to prepare a new SiO2-based bioactive glass with high Na2O content. The aim of this work is to investigate the real influence of the synthesis route (sol–gel versus melting) on the glass intrinsic properties and then, later, on the glass behavior and particularly on bioactivity. The obtained glass and its melt derived counterpart were characterized from structural and morphological (porosity, specific surface area) point of view. It could be noticed that the synthesis mode has no significant influence on glass structure. Conversely, the synthesis mode greatly influences the glass texture. The sol–gel derived glass exhibits a greatly higher specific surface area and pore volume than melt derived glass. This parameter may be a key factor of glass bioactivity.
Anita Lucas-Girot, Fatima Zohra Mezahi, Mohamed Mami, Hassane Oudadesse, Abdelhamid Harabi, Marie Le Floch, Journal of Non-Crystalline Solids 357 (2011) 3322–3327

B3175 – Transparent phosphosilicate glasses containing crystals formed during cooling of melts

Effect of P2O5–SiO2 substitution on spontaneous crystallization of SiO2–Al2O3–P2O5–Na2O–MgO melts during cooling was studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and rotation viscometry. Results show that addition of P2O5 leads to amorphous phase separation (APS), i.e., phosphate- and silicate-rich phases. It is due to the tendency of Mg2+ to form [MgO4] linking with [SiO4]. Molar substitution of P2O5 for SiO2 enhances the network polymerization of silicate-rich phase in the melts, and thereby the spontaneous crystallization of cubic Na2MgSiO4 is also enhanced during cooling of the melts. In addition, the sizes of the local crystalline and separated glassy domains are smaller than the wavelength of the visible light, and this leads to the transparency of the obtained glasses containing crystals
S.J. Liu, Y.F. Zhang, W. He, Y.Z. Yue, Journal of Non-Crystalline Solids 357 (2011) 3897–3900

B3185 – The characterization of structure, thermal stability and magnetic properties of Fe–Co–B–Si–Nb bulk amorphous and nanocrystalline alloys

Recently bulk amorphous alloys have attracted great attention due to their excellent magnetic properties. The glass-forming ability of bulk amorphous alloys depends on the temperature difference (?Tx) between glass transition temperature (Tg) and crystallization temperature (Tx). The increase of ?Tx causes a decrease of the critical cooling rate (Vc) and growth of the maximum casting thickness of bulk amorphous alloys. The aim of the present paper is to characterize the structure, the thermal stability and magnetic properties of Fe36Co36B19Si5Nb4 bulk amorphous alloys using XRD, Mössbauer spectroscopy, DSC and VSM methods. Additionally the magnetic permeability ?i (at force H ? 0.5 A/m and frequency f ? 1 kHz) and the intensity of disaccommodation of magnetic permeability ??/?(t1) (?? = ?(t1 = 30 s) ? ?(t2 = 1800 s)), have been measured, where ? is the initial magnetic permeability measured at time t after demagnetisation, the Curie temperature TC and coercive force Hc of rods are also determined with the use of a magnetic balance and coercivemeter, respectively. Fe–Co–B–Si–Nb bulk amorphous alloys were produced by pressure die casting with the maximum diameters of 1 mm, 2 mm and 3 mm. The glass transition temperature (Tg) of studied amorphous alloys increases from 807 K for a rod with a diameter of 1 mm to 811 K concerning a sample with a diameter of 3 mm. The crystallization temperature (Tx) has the value of 838 K and 839 K for rods with the diameters of 1 mm and 3 mm, respectively. The supercooled liquid region (?Tx = Tx ? Tg) has the value of about 30 K. These values are presumed to be the origin for the achievement of a good glass-forming ability of the Fe–Co–B–Si–Nb bulk amorphous alloy. The investigated amorphous alloys in the form of rods have good soft magnetic properties (e.g. Ms = 1.18–1.24 T). The changes of crystallization temperatures and magnetic properties as a function of the diameter of the rods (time of solidification) have been stated.
S. Lesz, R. Babilas, M. Nabia?ek, M. Szota, M. Dospia?, R. Nowosielski, Journal of Alloys and Compounds 509S (2011) S197–S201

B3184 – A study of electroless copper–phosphorus coatings with the addition of silicon carbide (SiC) and graphite (Cg) particles

Copper composite coating with graphite (Cg) and/or silicon carbide (SiC) particles were deposited by electroless plating. The surface morphology of the coatings that were analysed using scanning electron microscopy (SEM) showed that Cu particles were uniformly distributed. The obtained coating thickness was approximately ± 5 ?m. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques were used to characterise the structure and to study the phase transition of the coatings, respectively. Phases such as Cu, Cu2O, Cu3P, Cu3Si, SiC and Cg were observed from X-ray diffraction patterns and the presence of Cu2O, Cu3P and Cu3Si was confirmed by differential scanning calorimetry (DSC) studies. The results demonstrated that SiC and Cg particles have little influence on the phase transition of the coating. The hardness and wear resistance of Cu–P composite coatings were improved with the incorporation of SiC particles. The friction coefficient of Cu–P composite coatings decreased with the incorporation of Cg particles. Atomic force microscopy (AFM) results of coatings showed that the roughness of the coatings increased with the incorporation of SiC to the Cu–P coatings and decreased with the incorporation of Cg. Cu–P–Cg–SiC composite coatings showed a moderate roughness, hardness between Cu–P–SiC and Cu–P–Cg coatings, had low friction and good anti-wear properties. The anti corrosion resistance of the electroless Cu–P composite coatings on carbon steel were studied in 3.5% NaCl and 1 M HCl solutions by the potentiodynamic polarisation technique. The study revealed that the corrosion resistance increased with the incorporation of SiC particles in the Cu–P and Cu–P–Cg matrix but reduced with the incorporation of graphite.
Soheila Faraji, Afidah Abdul Rahim, Norita Mohamed, Coswald Stephen Sipaut, Surface & Coatings Technology 206 (2011) 1259–1268

B3183 – Manufacture of fibrous reinforcements for biocomposites and hemicellulosic oligomers from bamboo

Autohydrolysis of bamboo (treatments with hot, compressed water) resulted in liquors containing mainly hemicellulose-derived products (oligo- and mono-saccharides), and in spent solids (enriched in cellulose and lignin) with potential utility as a reinforcement for composites. Autohydrolysis of bamboo was carried out under a variety of operational conditions, and the resulting solid and liquid phases were assayed for composition. Kinetic models (based on pseudo-homogeneous, first-order, and irreversible reactions) were developed for data interpretation. Under selected conditions, 62.6% of the initial hemicelluloses present in the raw material were converted into oligosaccharides. The solid phase from the treatment leading to the maximal concentration of oligomeric compounds derived from hemicelluloses was employed as a fibrous reinforcement for polylactic acid (PLA)-based biocomposites. For comparative purposes, other three types of reinforcements from bamboo were also employed for making PLA-based composites: bamboo flour, short bamboo fibers, and large bamboo fibers. Compared to neat PLA, reinforcement with bamboo-derived materials resulted in increased stiffness and lower strain at break, whereas little effects were caused in tensile strength. Additional information on thermal analysis and surface morphological characteristics of biocomposites is also provided.
Daniel González, Valentín Santos, Juan Carlos Parajó, Chemical Engineering Journal 167 (2011) 278–287

B3193 – Development of a Low Cost CO2 Capture System with a Novel Absorbent under the COCS Project

The COCS (Cost Saving CO2 Capture System) Project had been carried out by RITE in collaboration with four Japanese companies from April 2004 to March 2009. It was the R&D project to reduce CO2 capture cost by half compared to the cost of a conventional technology for CO2 removal from a blast furnace gas in an integrated steel works. One of the main research issues in this project was to develop a novel absorbent which could be regenerated with a low thermal energy. RITE especially led the development of new absorbents. Initially amine solvents were investigated through laboratory-scale experiments, and then some selected solvents were evaluated at the 1t-CO2/d test plant. RITE successfully developed innovative amine absorbents, which have high absorption rate and low desorption energy of about 2.5–2.65 GJ/t-CO2 for CO2 capture from a blast furnace gas.
Kazuya Goto, Firoz Alam Chowdhury, Hiromichi Okabe, Shinkichi Shimizu, Yuichi Fujioka, Energy Procedia 4 (2011) 253–258

B3192 – Development and characterization of advanced 9Cr ferritic/martensitic steels for fission and fusion reactors

This paper presents the results on the physical metallurgy studies in 9Cr Oxide Dispersion Strengthened (ODS) and Reduced Activation Ferritic/Martensitic (RAFM) steels. Yttria strengthened ODS alloy was synthesized through several stages, like mechanical milling of alloy powders and yttria, canning and consolidation by hot extrusion. During characterization of the ODS alloy, it was observed that yttria particles possessed an affinity for Ti, a small amount of which was also helpful in refining the dispersoid particles containing mixed Y and Ti oxides. The particle size and their distribution in the ferrite matrix, were studied using Analytical and High Resolution Electron Microscopy at various stages. The results showed a distribution of Y2O3 particles predominantly in the size range of 5–20 nm. A Reduced Activation Ferritic/Martensitic steel has also been developed with the replacement of Mo and Nb by W and Ta with strict control on the tramp and trace elements (Mo, Nb, B, Cu, Ni, Al, Co, Ti). The transformation temperatures (Ac1, Ac3 and Ms) for this steel have been determined and the transformation behavior of the high temperature austenite phase has been studied. The complete phase domain diagram has been generated which is required for optimization of the processing and fabrication schedules for the steel.
S. Saroja, A. Dasgupta, R. Divakar, S. Raju, E. Mohandas, M. Vijayalakshmi, K. Bhanu Sankara Rao, Baldev Raj, Journal of Nuclear Materials 409 (2011) 131–139

B3191 – Optical and spectroscopic properties of germanotellurite glasses

In this work, new glass compositions in the TeO2–GeO2–Nb2O5–K2O system have been prepared and studied. The germanotellurite glasses were prepared by melt-quenching and their density, refractive index and characteristic temperatures have been determined. The structure of these glasses has been studied by infrared and Raman spectroscopies. The progressive replacement of TeO2 by GeO2 led to an increase of the glass transition and crystallisation temperatures of the glasses and a simultaneous decrease of their density and refractive index. Typical density and refractive index values of these glasses ranged from 4.98 to 3.85 g cm? 3 and 2.08 to 1.79, respectively, with increasing GeO2 content. The infrared spectra are dominated by a band ~ 640 cm? 1 in the tellurite glass and ~ 800 cm? 1 in the germanate glass. The Raman spectra of the germanotellurite glasses present an intense boson peak between ~ 34 and 47 cm? 1, together with high frequency peaks at ~ 670 cm? 1 and ~ 470 cm? 1 for high tellurite and high germanate glass compositions, respectively. The vibrational spectra of these germanotellurite glasses indicate that the glass network consists basically of TeO4 and [TeO3]/[TeO3 + 1] units, mixed with GeO4 and NbO6 polyhedra
Gonçalo Monteiro, Luís F. Santos, J.C.G. Pereira, Rui M. Almeida, Journal of Non-Crystalline Solids 357 (2011) 2695–2701

B3190 – Characteristic free volumes of bulk metallic glasses: Measurement and their correlation with glass-forming ability

A convenient method is proposed for the measurement of the characteristic free volumes, viz., the amount of excess free volume annihilation in structural relaxation Vf-sr and the amount of new free volume production in glass transition Vf-gt of bulk metallic glasses (BMGs) by thermal dilation (DIL) test. Through the DIL tests, the characteristic free volumes are found to be sensitive to the change of glass forming ability (GFA). The Pd40Cu30Ni10P20 BMG has a quite small Vf-sr. For a series of Fe–Cr–Mo–C–B–(Er) BMGs, Fe48Cr15Mo14C15B6Er2 with the largest GFA is identified to have the largest Vf-gt and smallest Vf-sr. The correlation between Vf-sr and the squares of critical diameters of these iron-based BMGs can be fitted as a negative exponential function with high accuracy.
Qiang Hu, Xie-Rong Zeng, M. W. Fu, Journal of Applied Physics 109, 053520 (2011)

B3189 – Interactions between silica sand and sodium silicate solution during consolidation process

This work is based on the knowledge of the consolidation of silica sand with an alkaline solution in order to determine the mechanisms that occur during the drying of sand and various alkaline solution mixtures. The investigations concern effects of sand distribution size, dilution of sodium silicate solutions and drying temperature of the mixtures on consolidation behaviour. The thermal analysis performed on fresh mixtures show a release of free-water from diluted silicate solution during the consolidation. SEM observations and compressive strength tests results indicate that interactions between sodium silicate binder and silica sand depend on drying temperature. Consequently two consolidation mechanisms are proposed: at low drying temperature (70 °C), sodium silicate acts as a thin layer of glue covering sand grains and bind them to each other, while at high temperature (150 °C), dissolution–precipitation reaction occurred in the mixture consolidating more strongly the granular system. The increase of Si/Na molar ratio in a sodium silicate solution containing silica sand is in accordance with the proposed mechanism.
S. Lucas, M.T. Tognonvi, J-L. Gelet, J. Soro, S. Rossignol, Journal of Non-Crystalline Solids 357 (2011) 1310–1318

B3188 – Effect of (Mo, W) substitution for Nb on glass forming ability and magnetic properties of Fe–Co-based bulk amorphous alloys fabricated by centrifugal casting

In this study, effects of simultaneous Mo and W substitution for Nb additions on the stability and magnetic properties of Fe–Co-based bulk metallic glass (BMG) alloys fabricated by centrifugal casting are investigated. The saturation magnetization (Js) and coercivity (Hc) for the as-cast Fe36Co36B19.2Si4.8X4 (X = Nb or Mo0.5W0.5) BMG alloys and melt-spun Fe36Co36B19.2Si4.8Mo2W2 were in the range of 1.02–1.57 T and 11.13–1685 A/m, respectively. The Fe36Co36B19.2Si4.8X4 (X = Nb or Mo0.5W0.5) BMG alloys in the shape of wedge with the maximum thickness of 1.5–2 mm were obtained successfully by means of conventional centrifugal casting. Replacing Nb with Mo0.5W0.5 deteriorates magnetic properties in bulk form and reduces the GFA of the alloy due to promoting the precipitation of non-magnetic compounds, while it results in good soft magnetic properties in melt-spun ribbon form.
Ilker Kucuk, Muratahan Aykol, Orhan Uzun, Mehmet Yildirim, Mehmet Kabaer, Nagehan Duman, Fikret Yilmaz, Kadir Erturk, M. Vedat Akdeniz, Amdulla O. Mekhrabov, Journal of Alloys and Compounds 509 (2011) 2334–2337

B3198 – Lead-free soldering: Investigation of the Cu–Sn–Sb system along the Sn:Sb = 1:1 isopleth

The Cu–Sn–Sb system has been experimentally investigated by a combination of optical microscopy, differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). DSC was used to identify a total number of five invariant ternary reactions and the Sn:Sb = 1:1 isopleth section up to 65 at.% Cu was constructed by combining the DSC data with the EPMA analyses of annealed alloys and literature information. The composition limits of the binary phases were detected.
Y. Yuan, G. Borzone, G. Zanicchi, S. Delsante, Journal of Alloys and Compounds 509 (2011) 1595–1600

B3187 – The reactive stabilization of Al–Zn foams using a powder metallurgy approach

The Al–Zn binary system was chosen in order to study the possibility of generating a reactive foam system within the semi-solid region. The idea is to create foam at lower temperatures than the melting point of pure aluminum using a transient liquid phase that softens the matrix prior to bulk expansion. This minimizes crack formation, collapse, drainage and deformation generated during processing. The Al–Zn foams were fabricated via the powder metallurgy route by hot compaction and subsequently foamed using TiH2 as a blowing agent. The investigated systems consist of low, medium and high concentrations of Zn (10 wt%, 33 wt% and 50 wt%) in an Al based matrix containing 0.8 wt% TiH2. High temperature in situ confocal microscopy was used to study the formation of the transient liquid phase of the compacted elemental powders. As the percentage of Zn was increased, the liquidus temperature of the melt was lowered along with an increase in the volume of transient liquid phase. This reduces the mismatch between the hydrogen release temperature of the blowing agent and the liquidus temperature of the melt, thus increasing foaming stability. Reasonable foam structures near 300 vol% expansion and fair pore distributions were achieved at low concentrations of Zn (10 wt%) only above the alloy liquidus point. The mechanical compressive strength properties of the alloyed foam systems were also assessed.
M. Lafrance, M. Isac, F. Jalilian, K.E. Waters, R.A.L. Drew, Materials Science and Engineering A 528 (2011) 6497– 6503

B3197 – CO-free hydrogen production over Au/CeO2–Fe2O3 catalysts: Part 1. Impact of the support composition on the performance for the preferential CO oxidation reaction

Ce–Fe mixed oxides were prepared by urea gelation coprecipitation method and used as supports of gold catalysts. The impact of the support composition on the catalytic performance for the preferential CO oxidation (PROX) was studied by varying the Ce/(Ce + Fe) ratio. A deep characterization study by different tools such as XRD, HRTEM, TPR and FTIR spectroscopy was undertaken in order to correlate the structural characteristics of the catalysts and the gold oxidation state and dispersion with the catalytic properties. The results revealed that the variation of the support composition led to significant differences in the gold particles size (in the range 1–25 nm), which affected strongly the CO oxidation activity of Au/CeO2–Fe2O3 catalysts under PROX conditions. The following activity order was observed: Au/CeO2 ? Au/Ce50Fe50 > Au/Ce75Fe25 > Au/Ce25Fe75 > Au/Fe2O3. The support with composition 50 wt.% CeO2–50 wt.% Fe2O3 appeared beneficial not only for nucleation and growth of highly dispersed gold particles (1–1.8 nm), but also for activation of oxygen and its mobility. Moreover, the presence of Fe2O3 in the supports composition improved the resistance towards deactivation by CO2. The CeO2–Fe2O3 supports comprised different amount of two phases: cubic CeO2-like solid solution and hematite. The analysis of the characterization data suggested that the solid solution formation probably proceeded via a dopant interstitial compensation mechanism.
T. Tabakova, G. Avgouropoulos, J. Papavasiliou, M. Manzoli, F. Boccuzzi, K. Tenchev, F. Vindigni, T. Ioannides, Applied Catalysis B: Environmental 101 (2011) 256–265

B3186 – Phase equilibrium of Bi2O3–Fe2O3 pseudo-binary system and growth of BiFeO3 single crystal

Thermodynamic decomposition of BiFeO3 (BFO) powder has been investigated and its peritectic transition temperature was determined to be 852±5 °C. Other typical characteristic temperatures in Bi2O3–Fe2O3 pseudo-binary phase diagram were reevaluated with high-purity starting materials. Based on the precision knowledge of improved Bi2O3–Fe2O3 pseudo-binary phase diagram, 1–2 mm sized single crystals BFO have been grown and characterized, showing ferroelectric transition temperature near 825 °C and remanent polarization about 70 ?C/cm2 along its polar axis.
J. Lu, L.J.Qiao, P.Z.Fu, Y.C.Wu, Journal of Crystal Growth 318 (2011) 936–941

B3196 – The energetics of nanophase calcite

Calcium carbonate (CaCO3) is an important component of the near-surface environment. Understanding the nature of its precipitation is important for a variety of environmental processes, as well as for the geologic sequestration of anthropogenic carbon dioxide. Calcite is the most thermodynamically stable bulk polymorph, but energy crossovers may exist that could favor the precipitation of vaterite or aragonite with decreasing particle size. The purpose of this study is to determine the surface energy of calcite, which is the first step towards understanding the effect of particle size on thermodynamic stability in the calcium carbonate system. The enthalpies of five well-characterized calcite samples (four nanophase and one bulk) were measured by acid solution isothermal and water adsorption calorimetric techniques. From the calorimetric data, the surface energies of calcite were determined to be 1.48 ± 0.21 and 1.87 ± 0.16 J/m2 for hydrous and anhydrous surfaces. These values are similar to those measured for many oxides but larger than predicted from computational models for idealized calcite surfaces. The surfaces of synthetic CaCO3 particles contain a range of planes and defect structures, which may give rise to the difference between the experimental and modeled values.
Tori Z. Forbes, A.V. Radha, Alexandra Navrotsky, Geochimica et Cosmochimica Acta 75 (2011) 7893–7905

B3195 – Thermal analysis and in vitro bioactivity of bioactive glass–alumina composites

Bioactive glass–alumina composite (BA) pellets were fabricated in the range 95/5–60/40 wt.% respectively and were heat-treated under a specific thermal treatment up to 950 °C. Control (unheated) and heat-treated pellets were immersed in Simulated Body Fluid (SBF) for bioactivity testing. All pellets before and after immersion in SBF were studied by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM-EDS) and X-ray Diffraction (XRD) analysis. All composite pellets presented bioactive response. On the surface of the heat-treated pellets the development of a rich biological hydroxyapatite (HAp) layer was delayed for one day, compared to the respective control pellets. Independent of the proportion of the two components, all composites of each group (control and heat-treated) presented the same bioactive response as a function of immersion time in SBF. It was found that by the applied methodology, Al2O3 can be successfully applied in bioactive glass composites without obstructing their bioactive response.
Xanthippi Chatzistavrou, Nikolaos Kantiranis, Eleana Kontonasaki, Konstantinos Chrissafis, Labrini Papadopoulou, Petros Koidis, Aldo R. Boccaccini, Konstantinos M. Paraskevopoulos, Materials Characterization 62 (2011) 118-129

B3194 – C- and N-truncated antimicrobial peptides from LFampin 265 – 284: Biophysical versus microbiology results

Lactoferrin is a glycoprotein with two globular lobes, each having two domains. Since the discovery of its antimicrobial properties, efforts have been made to find peptides derived from this protein showing antimicrobial properties. Most peptides initially studied were derived from Lactoferricin B, obtained from the protein by digestion with pepsin. More recently, a new family of antimicrobial peptides (AMPs) derived from Lactoferrin was discovered by Bolcher et al, and named Lactoferrampin (LFampin). The original sequence of LFampin contained residues 268 - 284 from the N1 domain of Lactoferrin. From this peptide, the Bolscher's group synthesized a collection of peptides obtained by extension and / or truncation at the C or N-terminal sides, in order to unravel the main structural features responsible for antimicrobial action. Here, we present results for three of these peptides, namely LFampin 265 - 284, LFampin 265 - 280, and LFampin 270 - 284. The peptides were tested against bacteria (E. coli and S. sanguinis), fungi (C. albicans), and model membranes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dimyristoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DMPG), and their mixtures at a ratio of 3 : 1 (DMPC : DMPG (3 : 1)). The ability to adopt a helical conformation was followed by a circular dichroism (CD), and the perturbation of the gel to the liquid-crystalline phase transition of the membrane was characterized by differential scanning calorimetry (DSC). Distinct behavior was observed in the three peptides, both from the microbiology and model membrane studies, with the biophysical results showing excellent correlation with the microbiology activity studies. LFampin 265 - 284 was the most active peptide toward the tested microorganisms, and in the biophysical studies it showed the highest ability to form an ?-helix and the strongest interaction with model membranes, followed by LFampin 265 - 280. LFampin 270 - 284 was inactive, showing marginal secondary structure and no interaction with the pathogen model membranes.
Regina Adão, Kamran Nazmi, Jan G.M. Bolscher, Margarida Bastos, J Pharm Bioallied Sci. 2011 Jan-Mar; 3(1): 60–69.

B3204 – Effect of shear on vesicle and lamellar phases of DDAB/lecithin ternary systems

The influence of shear flow on bilayer structures (vesicle and planar lamellar phases, L?), formed in DDAB/lecithin ternary systems, is studied by means of conventional rheology, Rheo NMR, and optical microscopy. The vesicles in the diluted (Lam,) phase are polydisperse multilamellae which turn into smaller monodisperse vesicles under shear. The concentrated (Lam2) phase is formed by non-oriented lamellae that do not surprisingly exhibit any pronounced shear-induced alignment prior to the transition into giant multilamellar vesicles. The biphasic region (Lam, + Lam2) shows a mosaic texture with a powder pattern indicating the prevalence of lamellae that transform into onions under shear.
Mohamed Youssry, Luigi Coppola, Isabella Nicotera, Gönül Ar, Claudia Schmidt, Journal of Colloid and Interface Science 358 (2011) 506–512

B3215 – Step-by-step design of novel biomimetic nanoreactors based on amphiphilic calix[4]arene immobilized on polymer or mineral platforms for destruction of ecological toxicants

The effective supramolecular catalysts based on amphiphilic calix[4]arene functionalized by iso-nonyl groups at the upper rim and polyoxyethylene groups at the lower rim (9CO9) are developed for the destruction of toxic phosphorus acid esters. In the microheterogeneous 9CO9–polyethyleneimine (PEI)–lanthanum salt systems, a step-by-step enhancement of the catalytic activity was accomplished and a ca. 200-fold acceleration of hydrolysis is reached. The effect is contributed by the superposition of the factors of micellar catalysis (the concentration of reagents and changes in their microenvironment) and homogeneous catalytic mechanisms, in particular the general basic catalysis by aminogroups of PEI and the electrophilic catalysis by the La(III) ions. A further increase in the catalytic performance is achieved through the covalent immobilization of 9CO9 on the mesoporous silica. An inhibition/catalysis inversion occurs upon transferring from the single 9CO9 solution to the supported 9CO9@SiO2 particles.
Lucia Zakharova, Yuliana Kudryashova, Alsu Ibragimova, Elmira Vasilieva, Farida Valeeva, Elena Popova, Svetlana Solovieva, Igor Antipin, Yulia Ganeeva, Tatiana Yusupova, Alexander Konovalov, Chemical Engineering Journal 185– 186 (2012) 285– 293

B3203 – The composites of magnesium hydride and iron-titanium intermetallic

Hydride-intermetallic composites MgH2 + X wt.% FeTi (X = 10, 30, 50) were synthesized by Controlled Mechanical Milling (CMM) in a magneto-mill. Their thermal behavior was investigated by Differential Scanning Calorimetry (DSC) and Temperature Programmed Desorption (TPD). It is found that the DSC hydrogen desorption peak temperature as well as the activation energy of hydrogen desorption of the MgH2 constituent in composites decreases linearly with increasing volume fraction of FeTi with a coefficient of fit R2 = 0.98. A doping of the MgH2 + FeTi composites with 5 wt.% of nanometric-size nickel (n-Ni) produced by Vale Inco Ltd. further reduces the DSC hydrogen desorption peak temperature of MgH2 to the temperature range below 300 °C for the MgH2 + 10 and 30 wt.% FeTi composites. The most effective reduction of the DSC hydrogen desorption peak temperature of the MgH2 constituent by as much as 60 °C due to the catalytic effect of n-Ni is observed for the MgH2 + 10 wt.% FeTi + 5 wt.% n-Ni composite. At this composition the composite also has hydrogen capacity slightly higher than 5 wt.%.
Robert A. Varin, Zbigniew Zaranski, Tomasz Czujko, Marek Polanski, Zbigniew S. Wronski, International Journal of Hydrogen Energy 36 (2011) 1177-1183

B3214 – Octane number enhancement studies of naphtha over noble metal loaded zeolite catalysts

An Indian industrial naphtha containing mixture of various hydrocarbons belong to n-paraffins, isoparaffins, naphthenes and aromatics falling in C5 to C9 carbon range has been studied for its octane boosting through the production of isoparaffins over various Pt loaded zeolite catalysts possessing different acidity and porosity properties. Optimum balance of acid and metal functionalities in 0.6 wt.% Pt loaded on BEA zeolite helped in achieving highest increase in research octane number (RON) from 44 to 80, suitable for gasoline applications, through the production of lower isoparaffins (iC4-iC6) along with C7+ isoparaffins.
Nagabhatla Viswanadham, Sandeep K. Saxena, M.O. Garg, Journal of Industrial and Engineering Chemistry 19 (2013) 950–955

B3202 – Water sorption and plasticization of an amorphous galacto-oligosaccharide mixture

Food-grade galacto-oligosaccharides (GOS) are commercially available as transparent syrups or dried powders. Food powders can be found in an amorphous metastable state which is very sensitive to changes in temperature and moisture content. In this work the impact of water content on thermal behavior and relative humidity on water sorption behavior of amorphous GOS powders were studied. Results from differential scanning calorimetry (DSC) and sorption isotherms suggest that GOS mixture studied, with high content of oligosaccharides, has low ability to crystallize. A dramatic decrease in the stability of GOS powders occurred above critical water content (12–14 g/100 g) and corresponding critical water activity (0.55–0.62). Above these conditions GOS powder lost its amorphous character, collapsed and shrank, as the powder became a transparent “solution-like” material. The knowledge about the physicochemical changes, acquired during the present study, should be used to a proper control of processing and storage conditions to achieve and maintain optimum powder quality with desired properties.
Duarte P.M. Torres, Margarida Bastos, Maria do Pilar F. Gonçalvese, Carbohydrate Polymers 83 (2011) 831–835 José A. Teixeirab, Lígia R. Rodrigues

B3213 – Effect of aluminium incorporation by the ‘‘pH-adjusting’’ method on the structural, acidic and catalytic properties of mesoporous SBA-15

A series of Al-SBA-15 catalysts in a wide compositional range (Si/Al = 130-5.2) was prepared by “pH-adjusting” aiming to evaluate the effect of aluminium incorporation on their structural, acidic and catalytic properties. The calcined materials were characterized by ICP, XRD, N2 adsorption/desorption, TEM, 27Al MAS NMR, microcalorimetry of ammonia adsorption and FTIR of adsorbed pyridine. It was found that the progressive incorporation of aluminium in SBA-15 has a positive effect on the structural and textural characteristics of catalysts as well as on the number of Brönsted and Lewis acid sites, whereas no net effect was observed on the relative distribution of acid sites according to their nature or strength. The catalytic properties of mesoporous SBA-15 aluminosilicates were finally evaluated by test-reactions in the liquid phase tert-butylation of phenol and isomerization of styrene oxide, under mild conditions. The catalytic results showed that the progressive incorporation of aluminium results in higher reaction rates in the O- and C-alkylation of phenol as well as isomerization of styrene oxide, providing evidence that the number of acid sites controls the catalytic activity of Al-SBA-15. On the other hand, the incorporation of aluminium had no effect on the selectivity to the reaction products, indicating that selectivity levels are controlled by the relative distribution of acid sites. It was also reported that Al-SBA-15 prepared by “pH-adjusting” are highly active catalysts in the isomerization of styrene oxide and very selective to phenylacetaldehyde.
A. Ungureanu, B. Dragoi, V. Hulea, T. Cacciaguerra, D. Meloni, V. Solinas, E. Dumitriu, Microporous and Mesoporous Materials 163 (2012) 51–64

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

B3211 – Hydration of Proteins: Excess Partial Enthalpies of Water and Proteins

Isothermal batch calorimetry was applied to study the hydration of proteins. The hydration process was analyzed by the simultaneous monitoring of the excess partial enthalpies of water and the proteins in the entire range of water content. Four unrelated proteins (lysozyme, chymotrypsinogen A, human serum albumin, and ?-lactoglobulin) were used as models. The excess partial quantities are very sensitive to the changes in the state of water and proteins. At the lowest water weight fractions (w1), the changes of the excess thermochemical functions can mainly be attributed to water addition. A transition from the glassy to the flexible state of the proteins is accompanied by significant changes in the excess partial quantities of water and the proteins. This transition appears at a water weight fraction of 0.06 when charged groups of proteins are covered. Excess partial quantities reach their fully hydrated values at w1 > 0.5 when coverage of both polar and weakly interacting surface elements is complete. At the highest water contents, water addition has no significant effect on the excess thermochemical quantities. At w1 > 0.5, changes in the excess functions can solely be attributed to changes in the state of the proteins.
Vladimir A. Sirotkin, Aigul V. Khadiullina, J. Phys. Chem. B 2011, 115, 15110–15118

B3199 – On the dependence of the properties of glasses on cooling and heating rates I. Entropy, entropy production, and glass transition temperature

The glass transition is theoretically described in terms of a generic non-equilibrium thermodynamics approach employing De Donder's structural order parameter method, appropriate expressions for the relaxation behavior of glass-forming systems and a simplified but qualitative correct model of glass-forming melts with one order parameter related to the free volume of the system. Employing this approach the behavior of a variety of thermodynamic quantities describing glass-forming systems in vitrification and devitrification processes is interpreted theoretically. The present paper is devoted to the computation of the entropy, the entropy production and the glass transition temperature in dependence on the cooling and heating rates, varying latter parameter in a broad interval. A comparison with experimental results is given and some further consequences and possible extensions are discussed briefly.
Timur V. Tropin, Jürn W.P. Schmelzer, Christoph Schick, Journal of Non-Crystalline Solids 357 (2011) 1291–1302

B3221 – Energetic and structural properties of 4-nitro-2,1,3-benzothiadiazole

The energetic study of 4-nitro-2,1,3-benzothiadiazole has been developed using experimental techniques together with computational approaches. The standard (p° = 0.1 MPa) molar enthalpy of formation of crystalline 4-nitro-2,1,3-benzothiadiazole (181.9 ± 2.3 kJ · mol?1) was determined from the experimental standard molar energy of combustion ?(3574.3 ± 1.3) kJ · mol?1, in oxygen, measured by rotating-bomb combustion calorimetry at T = 298.15 K. The standard (p° = 0.1 MPa) molar enthalpy of sublimation, at T = 298.15 K, (101.8 ± 4.3) kJ · mol?1, was determined by a direct method, using the vacuum drop microcalorimetric technique. From the latter value and from the enthalpy of formation of the solid, it was calculated the standard (p° = 0.1 MPa) enthalpy of formation of gaseous 4-nitro-2,1,3-benzothiadiazole as (283.7 ± 4.9) kJ · mol?1. Standard ab initio molecular orbital calculations were performed using the G3(MP2)//B3LYP composite procedure and several working reactions in order to derive the standard molar enthalpy of formation 4-nitro-2,1,3-benzothiadiazole. The ab initio results are in good agreement with the experimental data.
M.D.M.C. Ribeiro da Silva, V.L.S. Freitas, M.A.A. Vieira, M.J. Sottomayor, W.E. Acree Jr., J. Chem. Thermodynamics 49 (2012) 146–153

B3210 – Novel high-temperature, high-vacuum, all-metal sample cells for microcalorimetric measurements of solids

The design of a novel microcalorimetric sample cell which allows rapid transfer of heat from the sample to the cell wall is described. The solid sample is dispersed around the internal walls of the cell. Since the thermopiles of the microcalorimeter are in contact with the outer surface of the cell, the new design of the cell allows rapid recording of the heat generated by the sample. The robust all-metal cell allows in situ sample activation under conditions of high vacuum and at temperatures up to 500?°C. The dispersion of the sample avoids any “deep bed” effects where gas may not be able to diffuse freely to the surface of all of the sample, which may be the case when a thick layer or plug of the sample is used. The cell enables faster acquisition of heat data and minimizes effects of self-heating of the sample. A simple tool, which assists the introduction of the solid sample into the cell and a compact resistor-element, which fits inside the cell for calibration, are described
Eric N. Coker, Hellmut G. Karge, Rev. Sci. Instrum. 68 „12…, December 1997

B3220 – Correlation and prediction of mixing thermodynamic properties of ester-containing systems: Ester + alkane and ester + ester binary systems and the ternary dodecane + ethyl pentanoate + ethyl ethanoate

Excess thermodynamic properties and , have been measured for the ternary mixture dodecane + ethyl pentanoate + ethyl ethanoate and for the corresponding binaries dodecane + ethyl pentanoate, dodecane + ethyl ethanoate, ethyl pentanoate + ethyl ethanoate at 298.15 K. All mixtures show endothermic and expansive effects. Experimental results are correlated with a suitable equation whose final form for the excess ternary quantity ME contains the particular contributions of the three binaries (i–j) and a last term corresponding to the ternary, all of them obtained considering fourth-order interactions. The fit goodness for all mixtures is good and comparable to others equations taken from the literature. In this work the dissolution model for the binaries and ternary is analyzed with a special attention to ester–ester binaries whose behaviour is discussed. The application of the UNIFAC group contribution model to estimate the yields acceptable results for the binaries (with the exception of ester–ester) and for the ternary mixture.
Noelia Pérez, Luís Fernández, Juan Ortega, Francisco J. Toledo, Jaime Wisniak, J. Chem. Thermodynamics 54 (2012) 41–48

B3208 – Half-Heusler phase related structural perturbations near stoichiometric composition FeZnSb

Half-Heusler phases XYZ (Pearson symbol cF12) are chemically versatile and rich in physical properties. The half-Heusler phase in the Fe–Zn–Sb ternary system was reported in the year 2000. In this work, two new ternary phases are identified in the vicinity of the equiatomic composition FeZnSb in the same system: Fe1?xZnSb (tetragonal, space group P4/nmm, Pearson symbol tP6??, Z=2: a=4.1113(6) Å, c=6.0127(12) Å for x=0.08 (1), and a=4.1274(6) Å, c=6.0068(12) Å for x=0.12 (2)); and Fe7.87Zn6.72Sb8 (Fe0.98Zn0.84Sb) (3) (cubic, space group Fm-3m, Pearson symbol cF96??, Z=4, a=11.690(13) Å). 1 and 2 crystallize in the PbFCl-type structure, and 3 adopts a unique 2×2×2 supercell of a normal half-Heusler structure. The structures of both the tetragonal and cubic phases can be described as assemblies of half-Heusler structure related subunits. Electrical resistivity measurement on the pure sample of 2 shows it has metallic-like behavior, and its thermal and magnetic properties are also characterized.
Ding-Bang Xiong, Yufeng Zhao, Journal of Solid State Chemistry 184 (2011) 1159–1164

B3219 – CO2 adsorption on carbon molecular sieves

The effect of the textural properties of a series of commercial carbon molecular sieves (CMS), prepared from different polymeric precursors, on their ability for CO2 adsorption at different temperatures has been studied. The adsorbents have been characterized by N2 and CO2 adsorption at 77 and 273 K, respectively, together with measurements of immersion calorimetry into liquids of different molecular dimensions. The studied CMSs cover a wide range of porosity, from purely microporous carbons to samples containing wide micropores as well as a certain proportion of mesoporosity. Studies of CO2 adsorption, at atmospheric pressure (1 bar) and three different temperatures (273, 298 and 323 K), have shown that a high CO2 adsorption capacity requires the presence of a well-developed microporosity, as well as a high volume of narrow micropores. On the other hand, narrow micropores seem to be the key factor leading to a maximum capacity of CO2 adsorption, even at temperatures close to that of anthropogenic emissions of CO2.
A. Wahby, J. Silvestre-Albero, A. Sepúlveda-Escribano, F. Rodríguez-Reinoso, Microporous and Mesoporous Materials 164 (2012) 280–287

B3207 – Effects of short-time heat treatment and subsequent chemical surface treatment on the mechanical properties, low-cycle fatigue behavior and corrosion resistance of a Ni–Ti (50.9 at.% Ni) biomedical alloy wire used for the manufacture of stents

Cold-drawn and straight-annealed NiTi wires (50.9% Ni) with a tensile strength of 1650 MPa were subjected to heat treatments at 450, 510 and 600 °C for 10 min in air to simulate the shape-setting process in the manufacture of stents. Afterwards, the wires were chemically etched in acidic baths containing HF, HNO3 and H2O, followed by boiling in water. Variations in the internal structure, surface state and chemistry and transformation behavior of the wires due to these treatments were examined in detail by scanning and transmission electron microscopy, energy dispersion spectrometry, glow discharge spectrometry, X-ray photoelectron spectroscopy and differential scanning calorimetry. Mechanical properties were determined by tensile tests, and low-cycle fatigue behavior was measured by bend-type cyclic loading tests. Corrosion behavior was assessed by immersion tests and potentiodynamic measurements. A high tensile strength of the wire was shown to be attributable to a very fine-grained structure and work hardening. Heat treatment at 450–510 °C/10 min did not significantly affect the tensile strength of the wire. At 600 °C/10 min, the strength decreased by about 600 MPa due to recrystallization. The transformation temperatures first slightly increased after heat treatment at 450 °C and then reduced after treatments at higher temperatures due to changes in the composition of the B2 phase. The fatigue life was observed to prolong with both heat treatment and chemical etching. In contrast, the corrosion resistance worsened with heat treatment, but it improved significantly upon chemical etching. The observed behaviors are discussed in relation to the structural and chemical characteristics of the wires subjected to various treatment regimes.
D. Vojtech,?, M. Voderová, J. Kubásek, P. Novák, P. Sedáa A. Michalcová, J. Fojt, J. Hanus, O. Mestek, Materials Science and Engineering A 528 (2011) 1864–1876

B3218 – Structure–activity relationships of simple molecules adsorbed on CPO-27-Ni metal–organic framework: In situ experiments vs. theory

In this work we review experimental XRPD, EXAFS, Raman, IR, microcalorimetric data on the adsorption of H2O, NO, CO, CO2, N2, C2H4 and H2 molecules on CPO-27-Ni material, a metal–organic framework (MOF) showing a coordination vacancy at the Ni2+ site in its desolvated form. Literature data are complemented by few new experimental results. A systematic theoretical study performed at the B3LYP-D*/TZVP level of theory (using a periodic boundary conditions) allowed us to reach a complete understanding of the structural, vibrational and energetic features of the material in interaction with the different molecules obtained from the different experimental techniques. From both experimental and theoretical set of data, interesting trends have been obtained for the framework distances (Ni–O and Ni–Ni) and frequency shifts of the framework vibration modes as a function of the adsorption energy (enthalpy) of the different probe molecules. This multitechnical approach, already applied for UiO-66 MOF is of general validity and can be straightforwardly extended to all MOF materials.
L. Valenzano, J.G. Vitillo, S. Chavan, B. Civalleri, F. Bonino, S. Bordiga, C. Lamberti, Catalysis Today 182 (2012) 67– 79