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B2516 - DSC analysis of human fat tissue in alcohol-induced avascular necrosis of the femoral head. A preliminary study
The osteonecrosis or avascular necrosis of the antero-superior part of the human femoral head (ANFH) often causes incongruity in the hip joint and leads to severe pain and disability in middle aged patients. This abnormality often requires surgical intervention, mainly total hip arthroplasty (THA). The possible pathomechanisms of ANFH are fat embolism, arterial occlusion, fatty necrosis of osteocytes and intraosseous hypertension. Factors have been proposed in the literature that can lead to this condition are alcohol abuse, steroid therapy, metabolic changes, dyslipidaemia. In some case we can not verify any factor; these are the so called idiopathic ANFH cases. We observed macroscopic variation in colour and consistency of the subcutaneous fat tissue in patients with ANFH compared to osteoarthritis or hip fracture during THA procedures. Subcutaneous fat tissues during THA from a patient with ANFH due to alcohol abuse were compared with an otherwise healthy patient who underwent surgery due to traumatic hip fracture. No histological changes were notified in the size; shape of adipocytes and in the cells of the septae of the connective tissue. Gas chromatography showed that the patient with alcoholic ANFH had less long chain fatty acids. DSC revealed, that in case of non-necrotic sample as a reference, during heating between 0Ð100¡C two separable transitions are with Tm=5.7 and 9.9¡C, total ?H= Ð20.8 J gÐ1. In Ð20Ð100¡C range endotherms with Tm= Ð10.9 and 4.95¡C, total ?H= Ð75.8 J gÐ1 could be detected. In case of alcohol-induced avascular necrosis we have found endotherms between 0Ð100¡C with: Tm=7.3¡C, total ?H= Ð26.9 J gÐ1, and heating between Ð20Ð100¡C: Tm= Ð0.25¡C, total ?H= Ð103.3 J gÐ1 thermal parameters. The alteration in the fatty acid profile did not cause histological changes, but we were able to detect it with analytical methods e.g. DSC and gas chromatography.
Cs. Pintr, G. Bognr, B. Horvth, T. Sydo, E. Ligeti, J. Pulai, D. Lrinczy, Journal of Thermal Analysis and Calorimetry, Vol. 95 (2009) 3, 787Ð792
B2515 - DSC analysis of human fat tissue in idiopathic avascular necrosis of the femoral head. A preliminary study
Avascular necrosis of human femoral head (ANFH) causes incongruity in the joint that leads to disability in patients requires total hip arthroplasty (THA). Several etiological factors of ANFH have been proposed in the literature but there are cases of idiopathic origin. We observed macroscopic variation in quality of the subcutaneous fat tissue in patients with ANFH compared to patients with osteoarthritis or hip fracture during THA procedures. The samples were analysed by histology, gas chromatography (GC) and differential scanning calorimetry (DSC). Conclusion: the alteration in the fatty acid profile did not cause histological changes, however we could detect biochemical changes using DSC and GC.
Cs. Pintr, G. Bognr, B. Horvth, T. Sydo, E. Ligeti, J. Pulai, D. Lrinczy, Journal of Thermal Analysis and Calorimetry, Vol. 95 (2009) 3, 781Ð785
B2514 - Intermediate states of myosin head during ATP hydrolysis cycle in psoas muscle fibres by EPR and DSC. A review
Force generation in muscle during contraction arises from direct interaction of the two main protein components of the muscle, myosin and actin. The process is driven by the energy liberated from the hydrolysis of ATP. In the presence of CaATP the energy released from hydrolysis produces conformational changes in myosin and actin, which can be manifested as an internal motion of myosin head while bound to actin. It is suggested that myosin heads attached to actin produce conformational changes during the hydrolysis process of ATP, which results in a strain in the head portion of myosin in an ATP-dependent manner. These structural changes lead to a large rotation of myosin neck region relieving the strain. Paramagnetic probes and EPR spectroscopy provide direct method in which the rotation and orientation of specifically labelled proteins can be followed during muscle activity. In order to find correlation between local and global structural changes in the intermediate states of the ATPase cycle, the spectroscopic measurements were combined with DSC measurements that report domain stability and interactions. In the review a detailed description of the application of EPR and DSC techniques in muscle protein research will be given. The measurements show that the small local structural changes detected by EPR after nucleotide binding influence the global structure of protein system responsible for muscle contraction.
D. Lrinczy, J. Belgyi, Journal of Thermal Analysis and Calorimetry, Vol. 90 (2007) 2, 611Ð621
B2513 - Effect of phalloidin on the skeletal muscle ADP-actin filaments
The effect of phalloidin on the thermal stability of skeletal actin filaments polymerized from ADP-binding monomers was investigated with the method of differential scanning calorimetry. Phalloidin shifted the melting temperature of the ADP-F-actin from 59.1±1.0 to 80.0±1.2¡C. The stabilizing effect of phalloidin propagated cooperatively along the filament. The cooperativity factor according to the applied model was 1.07±0.11. With these measurements it was possible to demonstrate that the binding of phalloidin has lower influence on the adjacent protomers in ADP- (k=1) than in ATP-actin filaments (k=3).
Rka Duds, Tnde Kupi, Andrea Vig, J. Orbn, D. Lrinczy, Journal of Thermal Analysis and Calorimetry, Vol. 95 (2009) 3, 709Ð712
B2512 - Differential scanning calorimetric examination of the human skeletal muscle in a compartment syndrome of the lower extremities
The compartment syndromeÑconditions of elevated intramuscular pressureÑis one of the most serious complications of the injuries of the lower extremities. Early diagnosis is important, as delayed treatment leads to significant complications. The diagnosis of compartment syndrome is most commonly made by clinical examination and direct measurement of the intra-compartmental pressure. Our hypothesis was that in different stages of compartment syndrome there is a clear pathological abnormality in the tissue elements of the affected muscles, which is responsible for seriousness of the disease, and could be monitored besides the classical histological methods by differential scanning calorimetry. The thermal denaturation of different parts of human samples was monitored by a SETARAM Micro DSC-II calorimeter. All the experiments were performed between 0 and 100 ¡C. The heating rate was 0.3 K/min. DSC scans clearly demonstrated significant differences between the different types and conditions of samples (control: Tm = 55.5; 59.9 ¡Cand ?Hcal = 0.52 J/g, Gr. I.: Tm = 58.1; 62.2 ¡C and ?Hcal = 0.28 J/g, Gr. II.: Tm = 57.45; 61.5 ¡C and ?Hcal = 0.24 J/g, VolkmannÕs ischemic contracture Tm = 57.75; 61.8; 65.8 ¡C and ?Hcal = 0.74 J/g). These observations could be explained with the structural alterations caused by the biochemical processes. The heat capacity change between native and denatured states of muscle samples was significant, indicating significant water loosing during denaturation, but independent from the structural alterations.
N. Wiegand, L. Vamhidy, B. Patczai, E. Dmse, L. Kereskai, D. Lrinczy, J Therm Anal Calorim (2009) 98, 177Ð182
B2511 - Calorimetric examination of the human meniscus
Meniscus degeneration is a very frequent disease of human beings mainly in the developed countries. The ability of the meniscus to participate in load bearing, shock absorption, joint lubrication, and joint stability depends on the maintenance of its structural integrity. Therefore the pathology of the degeneration has been subject of many publications before. These studies all agreed that the grade of the degeneration correlated with the patientÕs age, weight, profession, and athletic activity [1]. These reviews also described the biochemical changes in the structure, too [2, 3]. In the current study authors examined degenerated human meniscus with differential scanning calorimetry and demonstrated thermal differences between healthy and intraoperatively removed pathological samples.
G. Blint, P. Than, I. Domn, N. Wiegand, G. Horvth, D. Lrinczy, Journal of Thermal Analysis and Calorimetry, Vol. 95 (2009) 3, 759Ð761
B2510 - Differential Scanning Calorimetry examination of transverse carpal ligament in carpal tunnel disease
The carpal tunnel syndrome Ð compression of the median nerve by the transverse ligament of the wrist Ð is a serious disease of the human hand. The electrophysiological changes in the median nerve can be easily followed by electroneurography (ENG). The degenerative changes in the collagen structures of the carpal ligament cause shrinking of the ligament and compression of the nerve. According to the present study we could demonstrate that DSC is a useful and well applicable method for the investigation of collagen tissue of the human carpal transverse ligament. DSC scans clearly demonstrated significant differences between the different types and conditions of samples (control: Tm=61.3¡C and ?Hcal=4.04 J gÐ1, mild: Tm=62¡C and ?Hcal=4.3 J gÐ1, middle: Tm=61.5¡C and ?Hcal=5.17 J gÐ1 as well as severe: Tm=61.85¡C and ?Hcal=8.44 J gÐ1). After these investigations we can choose the optimal time of surgical therapy of different clinical level carpal tunnel syndrome too.
N. Wiegand, L. Vmhidy, B. Patczai, E. Dmse, P. Than, L. Kereskai, D. Lrinczy, Journal of Thermal Analysis and Calorimetry, Vol. 95 (2009) 3, 793Ð796
B2509 - Effect of phalloidin on filaments polymerized from heart muscle ADP-actin monomers
The effect of phalloidin on filaments polymerized from ADP-actin monomers of the heart muscle was investigated with differential scanning calorimetry. Heart muscle contains a-skeletal and a-cardiac actin isoforms. In the absence of phalloidin the melting temperature was 55¡C for the a-cardiac actin isoform and 58¡C for the a-skeletal one when the filaments were generated from ADP-actin monomers. After the binding of phalloidin the melting temperature was isoform independent (85.5¡C). We concluded that phalloidin stabilized the actin filaments of a-skeletal and a-cardiac actin isoforms to the same extent when they were polymerized from ADP-actin monomers.
Andrea Vig, Rka Duds, Tnde Kupi, J. Orbn, G. Hild, D. Lrinczy, M. Nyitrai, Journal of Thermal Analysis and Calorimetry, Vol. 95 (2009) 3, 721Ð725
B2508 - Thermal transitions of actin
Actin is one of the main components in the eukaryote cells which plays significant role in many cellular processes, like force-generation, maintenance of the shape of cells, cell-division cycle and transport processes. In this study the thermal transitions of monomer and polymerized actins were studied to get information about the changes induced by polymerization and binding of myosin to actin using DSC and EPR techniques. The main thermal transition of F-actin was at 67.5¡C by EPR using spin-labeled actin (the relative viscosity change was around 62¡C), while the DSC denaturation Tms were at 60.3¡C for G-actin and at 70.5¡C for F-actin. Applying the LumryÐEyring model to obtain the parameters of the kinetic process and calculate the activation energy, a ÔbreakÕ was found for F-actin in the function of first-order kinetic constant vs. 1/T. This indicates that an altered interdomain interaction is present in F-actin. The addition of myosin or heavy meromyosin (HMM) in different molar ratio of myosin to actin has changed significantly the EPR spectrum of spin-labeled F-actin, indicating the presence of the supramolecular complex. Analyzing the DSC traces of the actomyosin complex it was possible to identify the different structural domains of myosin and actin.
D. Lrinczy, Zsuzsanna Vrtes, Franciska Knczl, J. Belgyi, Journal of Thermal Analysis and Calorimetry, Vol. 95 (2009) 3, 713Ð719
B2507 - Evaluation of hydrate nucleation trends and kinetic hydrate inhibitor performance by high-pressure differential scanning calorimetry
Due to the large number of tests, fluid volumes, and test times for traditional KHI evaluation; it was desirable to develop a quicker KHI performance-screening tool. This paper discusses a potential new method for evaluating KHI performance, which utilizes a high-pressure differential scanning calorimeter to study the nucleation of hydrates. Although the limits of the DSC method do not allow testing under exact field conditions, nor under shear conditions, it could be used to facilitate quicker initial screening of KHIs and evaluate KHI compatibility trends with other chemicals/fluids. Since hydrate formation is a stochastic event a large number of long traditional experiments are required to account for the dispersion of nucleation times. HP-DSC tests are significantly shorter, resulting in a higher out-put of data in a shorter time frame. Two DSC methods were explored to develop a quicker KHI screening tool. The first method utilized a stable water-in-oil emulsion to provide a large number of primarily independent nucleation events with uniform nucleation probability, in a single test. This method provides a very high statistical out-put in a single test, as each droplet can be treated as an individual nucleation event, analogous to a single rocking-cell or autoclave test. The second method was conducted in 100 % water-cut systems. Both methods reduce the overall test time required for KHI performance evaluation. In parallel studies at Nalco and CSM the hydrate nucleation trends were examined on a HP-DSC, for uninhibited and KHI inhibited fluids. The data from a select number of tests will be presented to illustrate the effectiveness of using the DSC for evaluating hydrate nucleation and KHI performance trends. This paper will also provide comparative data between traditional autoclave testing performed at Nalco, and the HP-DSC experiments, in an effort to develop a faster means to evaluate KHI performance.
Kevin McNamee, Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011), Edinburgh, Scotland, United Kingdom, July 17-21, 2011.
B2506 - Thermodynamic equilibrium data for mixed hydrates of CO2-N2 , CO2-CH4 and CO2-H2 in pure water and TBAB solutions
Mixed hydrates containing CO2 and N2, H2 or CH4 have been studied in this paper. Dissociation temperatures as function of the pressure of these hydrates, as well as the dissociation enthalpies, were determined at different gas proportions in pure water and TBAB solutions at 10, 20 30 and 40% using differential scanning calorimetry under pressure. The addition of TBAB in the solution increases the dissociation temperature of the hydrate and stabilizes it until a certain concentration comprised between 30 and 40 mass percent; after what the temperature decreases. The mixed hydrates of CO2+N2 have a thermodynamic behaviour which is closer to the pure CO2 hydrate at low prerssures; whereas the CO2+CH4 mixed hydrate dissociation temperatures as function of the pressure are quite close when the gas proportion varies. This indicates the selectivity of these mixed hydrates for one gas rather than another which is very useful for separation purposes.
Wassila Bouchafaa, Didier Dalmazzone, Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011), Edinburgh, Scotland, United Kingdom, July 17-21, 2011.
B2505 - The phase behaviours in mixed G + TetraÐN-Butylphosphonium borohydride and G + Tetra-N-Butylammonium hydroxie hydrates (where G = H2, N2)
The use of hydrogen hydrates stabilized by tetra-n-butylphosphonium borohydride (TBPBH4) and tetra-n-butylammonium hydroxide (TBAOH) as media for hydrogen storage was investigated using High Pressure Differential Scanning Calorimetry (HP-DSC) and gas volumetric analysis. In this study the TBPBH4 was obtained by reacting sodium borohydride with tetra-n-butylphosphonium bromide (TBPB). The TBPBH4 solutions were found to form hydrates at low temperature, and HP-DSC was used for determining the dissociation (p, T) points of mixed N2 + TBPBH4 and H2 + TBPBH4 hydrates at various salt concentrations. The results show that the new additive has very efficient stabilizing effect on the hydrate structure, the dissociation temperatures ranging from 280 to 295K, depending on the gas, in a pressure range of 0 to 40 MPa. The amount of chemically stored hydrogen was found to be 1.26 % in mass, using volumetric analysis of the H2 released by hydrolysis of the TBPBH4 compound in presence of acetic acid. The influence of the gas nature on the hydrate stability was investigated. The higher stabilization effect of nitrogen comparing to hydrogen was discovered. The possibility of gas enclathration and stabilizing effect of hydrogen into TBAOH - H2O hydrates was investigated as well. The formation of two hydrates with high dissociation temperatures were found in this system. Analysis of the p-T data of the TBAOH + water + H2 system revealed the quite promising hydrogen absorption properties of one of these hydrates.
Oleksandr Dolotko, Amir Abbas Karimi, Didier Dalmazzone, Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011), Edinburgh, Scotland, United Kingdom, July 17-21, 2011.
B2504 - Multi-scale assessment of the performance of kinetic hydrate inhibitors
The hydrate-inhibiting action of a fish Type III antifreeze protein (AFP), polyvinylpyrrolidone (PVP), and a proprietary, commercial chemical (HIW85281) was investigated at the macro scale using a stirred tank reactor and a high pressure differential scanning calorimeter, as well as at the molecular level using Raman an d NMR spectroscopy. The effect of the inhibitors on the induction time, growth and dissociation of a mixed gas hydrate (methane/ethane/propane) was assessed. Induction times were longer in the presence of all the inhibitors than in controls. Hydrate growth profiles demonstrated that the fastest to slowest growth rates were in order: water controls, PVP, AFP-III and HIW85281. Raman spectroscopic analysis showed that there was an in-homogeneity in guest composition within hydrates formed in the presence of kinetic inhibitors. In such cases, heavier hydrocarbon components tend to participate more in hydrate formation. The hydrate phase composition, cage occupancies of individual gases and hydration number were calculated in the presence of inhibitors using NMR spectroscopy
Nagu Daraboina, John Ripmeester, Virginia K. Walker, Peter Englezos, Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011), Edinburgh, Scotland, United Kingdom, July 17-21, 2011.
B2503 - Characterization of mixed CO2-TBPB hydrate for refrigeration applications
The present work investigates the use of semiclathrate hydrates, formed from CO2 + tetra-nbutylphosphonium bromide (TBPB) + water mixtures, as appropriate media for cold storage and distribution in refrigeration applications. Previous studies show that these hydrates are able to trap molecules of carbon dioxide resulting in mixed hydrates. Calorimetry devices were used for determining the dissociation enthalpies of mixed CO2 + TBPB hydrates under various stability conditions (P, T) and salt concentrations. The results reveal that mixed CO2 + TBPB hydrates can be considered as good candidates for air-conditioning, due to positive melting temperatures (between 282 to 289 K) at moderate CO2 pressures (between 0.5 to 2 MPa). A hydrate solid fraction model was developed based on a CO2 mass balance taking into account CO2 solubility in aqueous tetrabutylphosphonium salt solution. The salt effect parameter was evaluated in order to estimate the influence of TBPB on the CO2 solubility. Finally, in order to characterize the flow behavior of mixed CO2 + TBPB hydrate slurries, a rheological study was carried out in a dynamic loop and an Ostwald-de Waele model was obtained.
Pascal Clain, Anthony Delahaye, Laurence Fournaison, Salem Jerbi, Nadia Mayoufi, Didier Dalmazzone, Walter Frst, Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011), Edinburgh, Scotland, United Kingdom, July 17-21, 2011.
B2502 - Morphological and calorimetric investigation of hydrate-forming water in oil emulsions
Clathrate hydrates generate great interest and concern in the petroleum industry because of the potentially severe consequences of pipeline blockage by hydrate plug formation. A proper analysis of hydrates requires knowledge of their morphological, rheological and solid mechanical properties. This will require an understanding of the dynamic processes of formation and dissociation. This work addresses the issues of hydrate formation in water-in-oil emulsions through direct visualization and thermal analysis. Morphological analysis of hydrate growth at a single water drop immersed in a hydrocarbon phase is presented. Cyclopentane, which can form hydrates under atmospheric conditions, is used as a hydrate former and constitutes part or all of the oil phase in the emulsions studied. A hypothesis for hydrate formation in an emulsion is proposed based on the experimental findings from calorimetric studies. An analysis method is presented based on comparison of the heat flow for samples of hydrate-forming and non-hydrateforming emulsions. The proposed mechanism, supplemented by direct visualization of hydrate growth at single water drops, is that the hydrate formation is an interfacial process taking place at the interface between water drop and the continuous oil phase, leading to formation of a hydrate shell limiting the transport of hydrate former to free (liquid) water which remains trapped inside the hydrate layer. Generally crude oils carry a significant amount of natural surface-active agents (e.g. asphaltenes) and such surface-active agents will affect the hydrate morphology in a manner which increases the potential for hydrate plug formation in pipeline flow of emulsions. Evidence will be presented to show that surface active agents in the oil phase have a great impact on the cyclopentane hydrate morphology. Results are reported for Span 80 surfactant in the oil phase at different concentrations; sufficient levels of this surfactant lead to a hairy, mushy hydrate morphology as compared to an otherwise faceted shell formation. A detailed analysis is presented to explain the role of Span 80 on transport and driving force for the morphological development.
Prasad U. Karanjkar, Jae W. Lee, Jeffrey F. Morris, Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011), Edinburgh, Scotland, United Kingdom, July 17-21, 2011.
B2501 - Flow unit for measuring heats of mixing at subambient conditions
A type of mixing flow unit for BT 2.15D SETARAM calorimeter was designed for measuring heats of mixing of two liquids or a gas and a liquid. A cooling system using a cryostat circulating a cooling agent ethanol through the instrument was proposed and tested for temperatures down to ?50 ¡C. In addition, a special heat exchanger was constructed for cooling down fluids entering the calorimeter when experiments are performed at subambient temperatures. In comparison with cooling by liquid nitrogen, the operation is less expensive and no tedious manipulations with liquid nitrogen are needed. A procedure for measuring with the mixing unit was developed and the assembly was successfully tested in the temperature range from ?30 to 75 ¡C and at pressures up to 14 MPa using several binary systems liquid-liquid where reliable literature data were available. The proposed flow arrangement is much more efficient and convenient to use at subambient temperatures compared to conducting experiment in a batch mode, which is the approach still prevailing at these conditions.
Milo? Poledn'?ek, Vladim'r Majer, Vladim'r Hynek, Jacques Jose, Rev. Sci. Instrum. 76, 074102 2005
B2500 - Calorimetry in Nonstandard Conditions: The Noncrystalline Phases of Linear Polyethylene
A linear Union Carbide PE (UC) has been analyzed by nonstandard calorimetry with a common DSC calorimeter and a Setaram C80 calorimeter. Nonstandard calorimetry entails using a low rate of heating (0.5Ð1 K/min), a small mass (0.5Ð1.5 mg), and an open cell (O-cell) instead of the standard C-cell. Events in Ocells overlap less and occur with a faster kinetics than in C-cells. PE crystals are nascent, solution-grown (S-grown), press-grown (P-grown), and strained by extrusion. In Part A, the traces show that the phase-changes in the melt, previously observed in a C80 calorimeter (slow T-ramp) and characterized by ?Hnetwork, can be observed with a common DSC in nonstandard conditions. In Part B, the difference between the Cand O-cells and the changes in the main peak enthalpy (?Hortho) are of interest. The main result is that, in O-cells, the value of ?Hortho around Tortho, exceeds unambiguously in certain conditions ?Hortho found for perfect orthorhombic crystals. The main endotherm contains then another contribution, namely ?Hnetwork. Crystal reorganization during the slow T-ramp is followed in the C- and O-cells on S-grown crystals. In O-cells, lamellar thickening observed in the slow-ramp is more extensive. The ease of phase-change depends on the sample history. It is as follows: strained-part extruded > nascent > S-grown > P-grown. Co-operative chain motions are more hindered in the standard C-cells than in the O-cells. In Part C, lower values of m succeed in bringing phase-changes in P-grown (O-cells) samples. The origin of the events is discussed: three processes are thought to contribute to the phase-changes namely, melting of strained short-range order, activation of vibrations in the CH2 groups, and fast decay of chain orientation which occurs simultaneously with melting
Ilyes Jedidi, Zohra Ferhat-Hamida, Genevieve Delmas, Journal of Polymer Science: Part B: Polymer Physics, Vol. 45, 1932Ð1949 (2007)
B2499 - Calorimetric study of dissolution kinetics of phosphorite in diluted acetic acid
In this report, we present a thermodynamic and kinetic study of the selective dissolution of calcite from low-grade phosphate ores (Epirus area, Greece) by dilute acetic acid at isothermal conditions. A twin calorimeter with two identical membrane vessels, for the acid dissolution process, and for the reference was used. The curves of rate vs. time of the phosphorite dissolution for various temperatures show that the maximum ( & qmax) was increased, whereas the time (tpeak) to achieve the corresponding & qmax values was decreased, as the experimental temperature was increased. The dissolution enthalpy was increased from 13.1 to 16.7 kJ molÐ1, as the experimental temperature was increased from 10.0 to 28.0¡C. The chemical analysis of the supernatant solutions shows that the main process was the calcite dissolution. The reaction model with general form, ln(1/(1ÐX))=ktm, was found to fitted the experimental data regardless of the experimental temperature. These results were assigned in the presence of two different kinds of particles in the phosphorite. The activation energy of the dissolution process was found 69.7 kJ molÐ1. The SEM micrographs of acid dissolution samples showed two different textures after acid dissolution.
T. C. Vaimakis, E. D. Economou, C. C. Trapalis, Journal of Thermal Analysis and Calorimetry, Vol. 92 (2008) 3, 783Ð789
B2498 - Standard enthalpy of formation of disodium hydrogen phosphate hexahydrate and sodium diphosphate
Commercial disodium hydrogen phosphate dodecahydrate (Na2HPO4 12H2O) was used as a precursor for synthesizing disodium hydrogen phosphate hexahydrate (Na2HPO4 6H2O) and sodium diphosphate (Na4P2O7). The purity of the synthesized products was checked up by IR spectroscopy and X-ray diffraction. The heat of dissolution of these compounds, in acid solutions of several concentrations (w/w) of H3PO4 was measured in a C-80 SETARAM calorimeter. Many dilution and mixing processes were also realized in the calorimeter in order to get the standard enthalpy of formation of these products. The values obtained for the enthalpies of formation are: ( 3210.5) and ( 3516.5) kJ mol 1 for sodium diphosphate (Na4P2O7) and disodium hydrogen phosphate hexahydrate (Na2HPO4 6H2O), respectively.
H. Gmati-Ben Khaled, I. Khattech, M. Jemal, J. Chem. Thermodynamics 43 (2011) 521Ð526
B2497 - Calorimetric study of the reversibility of CO pollutant adsorption on high loaded Pt/carbon catalysts used in PEM fuel cells
A major obstacle to the broader use of fuel cells is the poisoning of supported Pt catalysts by the CO present in virtually all feeds. In this paper, the microcalorimetry technique was employed to study and compare the CO adsorption properties of different commercial carbon-supported platinum catalysts with high Pt loading, aimed to be used in proton exchange membrane fuel cells (PEMFCs) applications. Combined with other techniques of characterization, such as BET, XRD, TPD-MS and TPR, adsorption microcalorimetry has permitted a better understanding of the studied systems. The pore architecture of Pt/C catalysts was found to influence the kinetics of heat release during CO adsorption. The accessibility of CO molecules to the adsorption sites increased with the mesoporosity of the catalyst. The degree of catalyst poisoning by CO upon successive air/H2/CO cycles varied between 2 and 30% for the different studied samples. These results confirm that the surface chemistry of the catalyst, and in particular the Pt deposition method, affects the surface site energy distribution and consequently the adsorptive properties towards H2 and CO. It was found that both H2 and CO are chemisorbed on the investigated samples. Pt/C powders exhibit higher differential heats of carbon monoxide adsorption in comparison with hydrogen adsorption. A reaction between pre-adsorbed H2 and CO from the gas phase takes place on Pt/C catalysts as a result of competitive adsorption
Georgeta Postole, Simona Bennici, Aline Auroux, Applied Catalysis B: Environmental 92 (2009) 307Ð317
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- July 15, 2012 - July 20, 2012
BZA 2012
Chester, EnglandThe 35th Annual British Zeolite Association Meeting15th - 20th July 2012University of Chester in northwest EnglandThe 2012 meeting of the British Zeolite Association will be held at the University of Chester in northwest England. This triennial, Chislehurst-style BZA meeting, organised along the lines of a Gordon Conference, will be limited to 120 participants.The BZA welcomes contributions from all fields of zeolite, microporous and mesoporous materials science, including synthesis, structure, applications, characterisation, catalysis and computational studies.
- June 26, 2012 - June 29, 2012
CTEC 2012
Lyon, FranceCalorimetry and Thermal Effects in CatalysisCalorimetry and thermal analysis methods, alone or linked to other techniques, applied to the characterization of catalysts, supports and adsorbents, and to the study of catalytic reactions in various domains: air and wastewater treatment, clean and renewable energies, refining of hydrocarbons, green chemistry, hydrogen production and storage, CO2 capture...
- June 18, 2012 - June 22, 2012
EU BC&E 2012
Milano, Italy20th European Biomass Conference and Exhibition18 - 22 June 2012 at the Milano Convention Centre in Milano, ItalyWith this event, we will continue the biomass specialist's role as the leading technical platform covering all aspects of biomass from research to industry and markets.
- June 10, 2012 - June 15, 2012
SUMMER SCHOOL OF CALORIMETRY 2012
Lyon, FranceSummer School of Calorimetry 2012 "Calorimetry and thermal methods in catalysis"Calorimetry and thermal analysis methods, alone or linked to other techniques, applied to the characterization of catalysts, supports and adsorbents, and to the study of catalytic reactions in various domains: air and wastewater treatment, clean and renewable energies, refining of hydrocarbons, green chemistry, hydrogen production and storage, CO2 capture...
- June 05, 2012 - June 08, 2012
AICAT 2012
Rome, ItalyAICAT 2012Sapienza University of RomeJune 5-8 2012AICAT 2012 is jointly organized by the Italian Association of Calorimetry and Thermal Analysis (AICAT) and by Interdivisional Group of Calorimetry and Thermal Analysis (GICAT) of the Italian Chemical Society (SCI) and represents the main scientific meeting of these Associations. The Congress aim is to provide to the scientists working in Calorimetry, Thermal Analysis and closely related topics an opportunity for an exchange of scientific information, critical discussion and advanced planning on fundamental and applied research aspects of interest in this field.
- May 28, 2012 - June 01, 2012
2012 Fiery Ice
Sapporo, Hokkaido, Japan2012 Fiery Ice8th International Workshop on Methane Hydrate Research & DevelopmentWith great pleasure, we announce that 8th International Workshop on Methane Hydrate Research & Development (Fiery Ice from the Seas) is being held in Sapporo, Japan at refreshing season, 28th of May to 1st of June, 2012.
- May 27, 2012 - May 31, 2012
BiPoCo 2012
Siófok, Lake Balaton - Hungary BiPoCo 2012,an International Conference onBio-Based Polymers and CompositesMay 27-31, 2012Siófok, Lake Balaton - HungaryDownload the First circular
- May 22, 2012 - May 24, 2012Toulouse, FranceThe 43rd Calorimetry and Thermal Analysis DaysDownload the conference flyer
- May 20, 2012 - May 25, 2012
HTCPM 2012
Les Embiez, FranceHTCPM 20128th International Symposium on High-Temperature Corrosion and Protection of Materials20 - 25 May, 2012Les Embiez, France The goal of this international symposium is to reflect the interests of the major industries dependent on the successful application of high-temperature materials, providing a periodic updating on the current research and understanding in these areas.
- May 16, 2012 - May 18, 2012
INNOSTOCK 2012
Lleida, SpainINNOSTOCK 2012The 12th International Conference on Energy Storage16-18 May 2012Innostock 2012 is part of the Stock conference series sponsored by the ECES IA of the International Energy Agency.Innostock 2012 will gather the world’s leading specialists and academic researchers within the field of energy efficiency through energy storage. Energy storage will present in all its topics:• Underground thermal energy storage• Sensible, latent and thermochemical energy storage• Electrical storage
- May 14, 2012 - May 18, 2012
11th International Hydrocolloids Conference
Purdue University, USA11th International Hydrocolloids ConferenceBiofunctionality and Technofunctionality of Hydrocolloids14-18 May 2012, Whistler Center for Carbohydrate Research, Purdue University, USAThe 11th International Hydrocolloids Conference is organized by the world-renowned Whistler Center for Carbohydrate Research and will be held at The Stewart Center at Purdue University, Indiana, USA.
- April 30, 2012 - May 03, 2012
Carbon Capture Utilization & Sequestration
Pittsburgh, Pennsylvania - United States 11th Annual Conference on Carbon Capture Utilization & Sequestration April 30 - May 3, 2012Pittsburgh, Pennsylvania The 2012 Conference program follows in the footsteps of the past 10 events, with an added emphasis this year on potential utilization of anthropogenic carbon emissions that is reflected in the new name of the conference. The focus is on systems and technologies that are being or could be deployed in the U.S. and North America.
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