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  • Articles  (203)
  • kinetics  (133)
  • DSC
  • Springer  (203)
  • American Association for the Advancement of Science
  • American Meteorological Society
  • 1995-1999  (119)
  • 1990-1994  (84)
  • 1999  (119)
  • 1992  (84)
  • 1
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of MnO2 dissolution in H2SO4 in the presence of pyrite (1999)
    Springer
    Journal of applied electrochemistry 29 (1999), S. 191-200 
    Details
    ISSN: 1572-8838
    Keywords: cyclic redox reaction ; dissolution ; kinetics ; manganese dioxide ; mechanism ; pyrite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper describes a study of the kinetics and mechanism of MnO2 dissolution in H2SO4 in the presence of pyrite through leaching and electrochemical parameters. Manganese(iv) was found to dissolve mainly through reduction by the ferrous ion generated during oxidation of pyrite by the ferric ion. The oxidation which is slower and rate controlling may proceed through two different reactions, one producing S0 and the other SO42−. Manganese dissolution runs at the same rate as that of pyrite oxidation by maintaining ferrous ion concentration at a much lower level than that of ferric. Kinetic equations based on corrosion coupling principles are developed to explain the observed leaching behaviour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003490810114
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of ionic interactions on the rates of reduction of Cu(II) with H2O2 in aqueous solutions (1992)
    Springer
    Journal of solution chemistry 21 (1992), S. 1271-1287 
    Details
    ISSN: 1572-8927
    Keywords: Cu(II) ; kinetics ; reduction ; temperature dependence ; H2O2, NaCl, NaBr, NaClO4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The rates of reduction of Cu(II) with H2O2 have been measured in NaCl and NaBr solutions and mixtures with NaClO4 as a function of pH (6 to 9), temperature (5 to 45°C) and ionic composition (0.1 to 6M). The effect of pH on the rates was found to be independent of temperature and ionic composition. The rates increased as a function of [H+] raised to the power of 1.3 to 1.6. Speciation calculations indicate that this pH dependence can be attributed to Cu(OH)2 being the reactive species. The rate constants in NaCl and NaBr and mixtures with NaClO4 were independent of ionic strength, but proportional to the halide concentration raised to the power of 2.0 (0.2 to 2.6M). These results can be attributed to Cu(OH)2Cl 2 2− being the reactive species to reduction with H2O2. The Cu(I) halide complexes formed from the reduction are not easily oxidized with O2 or H2O2. The faster rates in Br− solutions, which form stronger complexes with Cu+, support this contention. Measurements made in NaCl with added NaHCO3, NaB(OH)4 EDTA, NTA and glycine were also made. These measurements indicate that the CuL complexes (L=B(OH) 4 − , CO 3 2− , EDTA, NTA, and glycine) are not very reactive to reduction with H2O2. The addition of Mg2+ or Ca2+ caused the rates to increase due to the formation of MgL or CaL complexes and the resultant release of reactive Cu2+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00667222
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  • 3
    Electronic Resource
    Electronic Resource
    Factors affecting bioleaching kinetics of sulfide ores using acidophilic micro-organisms (1999)
    Springer
    BioMetals 12 (1999), S. 1-10 
    Details
    ISSN: 1572-8773
    Keywords: acidophilic ; strain ; oxidation ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Recovery of metal values from sulfide ores by use of acidophilic microorganisms is gaining importance. A number of commercial/pilot plants are setup to find out the techno-economic feasibility of the overall process. The main drawback in the process is the slow kinetics of dissolution of metal values from the sulfide ores. To make the technology e attractive the kinetics should be improved considerably. There are various factors which determine the overall kinetics such as bacterial activity and concentration, iron and sulfur oxidation, oxygen consumption, reactor design and nature of ore. A brief review has been made dealing with the above parameters
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009228210654
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  • 4
    Electronic Resource
    Electronic Resource
    Study on thermal transitions of toluene diisocyanate-based polyurethane elastomers with poly (tetramethylene oxide) as the soft segment by TSC/RMA, DSC and DMA thermal analyzers (1999)
    Springer
    Journal of polymer research 6 (1999), S. 67-78 
    Details
    ISSN: 1572-8935
    Keywords: TDI-based polyurethane elastomers ; Tg ; Tglobal transition ; DSC ; TSC/RMA ; DMA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Thermal transitions of TDI-based polyurethane elastomers with PTMO as the soft segment were characterized by the depolarization technique in TSC and by using with the thermal windowing technique on selected specimens in the RMA measurements. Results indicate that the broadened thermal transition in the glass transition region as observed in the DSC thermogram is related to the combined Tg transition and the Tglobal transition in the TSC spectrum. This Tglobal transition is associated with the macromolecular property as detected by tan δ in DMA measurement. The increase in the Tg with a high NCO content may be explained by the structural modification found on the urethanic chain with the additional linkage of the hard segment that affects the cooperative motion of the molecular chain. Data measured from DSC, TSC/RMA and DMA with simulated DEA and wide angle X-ray data are presented for the characterization of the polyurethanes. The RMA measurement leads to a compensation search on Tg transition and provides pertinent thermokinetic data that correlates the NCO content with changes in enthalpy and entropy on the relaxation behaviors in the Tg transition of polyurethane elastomers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0073-4
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  • 5
    Electronic Resource
    Electronic Resource
    Degradation of Cellulosic Materials Under the Alkaline Conditions of a Cementitious Repository for Low- and Intermediate-Level Radioactive Waste. II. Degradation Kinetics (1999)
    Springer
    Journal of polymers and the environment 7 (1999), S. 41-51 
    Details
    ISSN: 1572-8900
    Keywords: Cellulose ; alkaline degradation ; peeling off ; degree of polymerization ; kinetics ; (gluco)isosaccharinic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The degradation of cellulosic materials, differing mainly in the degree of polymerization and the number of reducing end groups, was studied under the alkaline conditions similar to those existing in a cementitious repository for low- and intermediate-level radioactive waste (pH 13.3, T = 25°C). The kinetics of alkaline degradation (peeling-off reaction) were studied and the data analyzed by the model of Haas et al. [13]. The observed kinetic parameters for the propagation reaction and overall stopping reaction were compared with literature data. Although measured under different experimental conditions, literature data and data from this study show a consistent picture. Differences in the extent of degradation observed for the different cellulosic materials could be satisfactorily explained by differences in reducing end group content and, consequently, by differences in the degrees of polymerization. Besides the number of reducing end groups, the degree of amorphousness also plays an important role. The main degradation products formed under the experimental conditions used are α- and β-(gluco)isosaccharinic acid. This is in agreement with many other studies on alkaline degradation of cellulose. The two isomers are formed in roughly equal amounts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021894102937
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  • 6
    Electronic Resource
    Electronic Resource
    Sorption Equilibria and Kinetics of Hydrocarbons onto Activated Carbon Samples Having Different Micropore Size Distributions (1999)
    Springer
    Adsorption 5 (1999), S. 25-37 
    Details
    ISSN: 1572-8757
    Keywords: micropore size distribution ; activated carbon ; adsorption ; desorption ; equilibrium ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract This paper deals with the prediction of adsorption equilibrium and kinetics of hydrocarbons onto activated carbon samples having different micropore size distribution (MPSD). The microporous structure of activated carbon is characterised by the distribution of slit-shaped micropores, which is assumed to be the sole source of surface heterogeneity. The interaction between adsorbate molecule and pore walls is described by the Lennard-Jones potential theory. Different adsorbates have access to different pore size range of activated carbon due to the size exclusion, a phenomenon could have a significant influence on both multicomponent equilibria and kinetics. Activated carbons with three different MPSDs are studied with ethane and propane as the two model adsorbates. The Heterogeneous Macropore Surface Diffusion model (HMSD) is employed to simulate adsorption kinetics. The simulation results show that the MPSD is an important factor affecting both the multicomponent equilibria and kinetics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026481704926
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  • 7
    Electronic Resource
    Electronic Resource
    Furfural hydrogenation over carbon‐supported copper (1999)
    Springer
    Catalysis letters 60 (1999), S. 51-57 
    Details
    ISSN: 1572-879X
    Keywords: furfural hydrogenation ; Cu/carbon catalysts ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Furfural hydrogenation over copper dispersed on three forms of carbon – activated carbon, diamond and graphitized fibers – were studied. Only hydrogenation of the C=O bond to form either furfuryl alcohol or 2‐methyl furan occurred at temperatures from 473 to 573 K. Reduction at 573 K gave the most active catalysts, all three catalysts had activation energies of 16 kcal/mol, and turnover frequencies were 0.018–0.032 s-1 based on the number of Cu0 + Cu+ sites, which were counted by N2O adsorption at 363 K and CO adsorption at 300 K, respectively. The Cu/activated carbon catalyst showed no deactivation during 10 h on stream, in contrast to the other two catalysts. A simple Langmuir–Hinshelwood model invoking two types of sites was able to fit all kinetic data quite satisfactorily, thus it was consistent with the presence of both Cu0 and Cu+ sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019090520407
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  • 8
    Electronic Resource
    Electronic Resource
    Study of the ammonia decomposition over iron catalysts (1999)
    Springer
    Catalysis letters 60 (1999), S. 167-171 
    Details
    ISSN: 1572-879X
    Keywords: ammonia decomposition ; iron catalyst ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The decomposition of ammonia is a reaction associated with the process of the nitriding of metals. The kinetics of the ammonia decomposition on iron catalysts has been studied using a differential reactor with internal mixing. The balance between the inlet and outlet ammonia quantity has been used to determine the degree of conversion. The rate of ammonia decomposition could be described by the following expression: r = k0 exp (Ea/RT)pNH3. The activation energy of the ammonia decomposition process has been found for samples with potassium as E a= 96 kJ/mol, for samples without potassium as E a= 87 kJ/mol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019007024041
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  • 9
    Electronic Resource
    Electronic Resource
    Pure and Binary Gas Adsorption Equilibria and Kinetics of Methane and Nitrogen on 4A Zeolite by Isotope Exchange Technique (1999)
    Springer
    Adsorption 5 (1999), S. 145-158 
    Details
    ISSN: 1572-8757
    Keywords: kinetics ; isotope-exchange ; nitrogen ; adsorption ; methane ; zeolite ; equilibria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The Isotope Exchange Technique (IET) was used to simultaneously measure pure and binary gas adsorption equilibria and kinetics (self-diffusivities) of CH4 and N2 on pelletized 4A zeolite. The experiment was carried out isothermally without disturbing the adsorbed phase. CH4 was selectively adsorbed over N2 by the zeolite because of its higher polarizability. The multi-site Langmuir model described the pure gas and binary adsorption equilibria fairly well at three different temperatures. The selectivity of adsorption of CH4 over N2 increased with increasing pressure at constant gas phase composition and temperature. This curious behavior was caused by the differences in the sizes of the adsorbates. The diffusion of CH4 and N2 into the zeolite was an activated process and the Fickian diffusion model described the uptake of both pure gases and their mixtures. The self-diffusivity of N2 was an order of magnitude larger than that for CH4. The pure gas self-diffusivities for both components were constants over a large range of surface coverages (0 〈 θ 〈 0.5). The self-diffusivities of CH4 and N2 from their binary mixtures were not affected by the presence of each other, compared to their pure gas self-diffusivities at identical surface coverages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008917308002
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  • 10
    Electronic Resource
    Electronic Resource
    The detailed kinetics of the desorption of hydrogen from polycrystalline copper catalysts (1999)
    Springer
    Catalysis letters 59 (1999), S. 143-149 
    Details
    ISSN: 1572-879X
    Keywords: hydrogen ; desorption ; copper ; activation energy ; kinetics ; order of desorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics of desorption of hydrogen from the copper component of an alumina-supported polycrystalline copper catalyst has been studied in detail by temperature-programmed desorption (TPD). Line-shape analysis of the hydrogen TPD spectra shows: (i) that the desorption is second order, (ii) that the desorption activation energy is in the range 64–68 kJ mol−1 in the coverage range 7–44% of a monolayer, and (iii) that the desorption pre-exponential term has a value ∼10−5 cm2 s−1 atom−1 consistent with the desorption being second order, involving mobile adsorbates and a mobile desorption transition state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019080823616
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  • 11
    Electronic Resource
    Electronic Resource
    Increased sensitivity of an enzyme immunoassay (ELISA) for the determination of triazine herbicides by variation of tracer incubation time (1992)
    Springer
    Microchimica acta 108 (1992), S. 29-40 
    Details
    ISSN: 1436-5073
    Keywords: atrazine ; terbuthylazine ; sequential binding ; kinetics ; cross-reactivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Immunoassays for triazine herbicides were tested for their reaction to the variation of the tracer incubation time. By application of a sequential technique the measuring range of atrazine could be expanded to five decades and the total duration of the test could be reduced to about 30 min. In an optimized version a lower detection limit of 9 pmol/l (2 ng/l) was achieved. The detection limit of a sensitive immunoassay for terbuthylazine is also below the concentration limit demanded of the German drinking water regulation (100 ng/l) and reaches 130 pmol/l (30 ng/l). Short tracer incubation times did not lead to increased cross-reactivities in contrast to theoretical models [1, 2]. Different mechanisms, which could cause a shift of the center point of the calibration curve, are discussed, including kinetic considerations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01240369
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  • 12
    Electronic Resource
    Electronic Resource
    Growth of Ordered Domains in a Computer Model Alloy with Lattice Misfit (1999)
    Springer
    Journal of statistical physics 95 (1999), S. 23-43 
    Details
    ISSN: 1572-9613
    Keywords: model alloy ; Monte Carlo ; elastic interactions ; phase separation ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study via Monte Carlo simulations the influence of elastic interactions on the ordering and decomposition of a two-dimensional model binary alloy with antiferromagnetic nearest and ferromagnetic next nearest neighbor type interactions following a quench into the coexistence region. The elastic interaction leads to the development of a platelet morphology for the segregated ordered and disordered regions. A length scale characterizing the coarsening process follows a law of the type R=a+bt 1/3 with the growth b decreasing with the amount of ordered phase; this appears to be due to the presence of anti-phase boundaries between neighboring domains ordered on different sublattices which are difficult to eliminate. The application of uniaxial external stress results in “rafting” of the domains. Many of the simulation results are in agreement with experimentally observed effects in nickel-base superalloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004569209618
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  • 13
    Electronic Resource
    Electronic Resource
    Absorption of intramuscular phenobarbitone in children with severe falciparum malaria (1992)
    Springer
    European journal of clinical pharmacology 42 (1992), S. 107-110 
    Details
    ISSN: 1432-1041
    Keywords: Phenobarbitone ; Cerebral malaria ; P.falciparum ; kinetics ; drug absorption ; children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of intramuscular phenobarbitone 7 mg·kg−1 was studied in 11 Karen children aged between 1.7 and 11 y with severe falciparum malaria. Eight of the children were comatose. Clinical findings were compared with those in 9 further children with severe malaria of similar age range (four of whom were unconscious), who received an identical placebo. One child, who had received placebo, had repeated convulsions and died 1 h after admission to hospital. The remainder made an uncomplicated recovery. There were no convulsions subsequent to treatment, although the study was too small to assess anticonvulsant efficacy. There was no observable toxicity, but phenobarbitone recipients had a significant tendency to deepen in their level of coma or to become sleepy within the 4 h after drug administration. Phenobarbitone was rapidly absorbed, reaching a mean (range) peak concentration of 34.2 [29.3–42.6] μmol·l−1 in a median (range) of 4 (2.5–12) h. These values are comparable to those previously reported in healthy children and in children with febrile convulsions. Intramuscular phenobarbitone is well absorbed in children with severe malaria; the optimum prophylactic anticonvulsant dose remains to be determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314929
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  • 14
    Electronic Resource
    Electronic Resource
    Kinetics of atrial natriuretic peptide in young and elderly subjects (1992)
    Springer
    European journal of clinical pharmacology 42 (1992), S. 449-452 
    Details
    ISSN: 1432-1041
    Keywords: Atrial natriuretic peptide ; kinetics ; ageing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To study the influence of age on the kinetics of atrial natriuretic peptide (ANP) in man, human (99–126) ANP 2.0 μg·min−1 was infused IV for 60 min in 8 healthy young (18 to 25 y) and 9 healthy elderly (71 to 84 y) subjects. Both baseline ANP values and the levels at the end of infusion were higher in the elderly subjects. The mean residence time of ANP in the two age groups was not significantly different, whereas total body clearance (CL) was markedly diminished in the elderly as compared to the young subjects (mean±SD 3.1±1.0 l·min−1 and 6.2±4.1 l·min−1, respectively). The apparent volume of distribution at steady state was lower in the elderly than in the young, but the difference was not significant (mean±SD 44±19 and 103±111, respectively. The decrease in CL largely explained the higher ANP levels found in the elderly subjects. The MRT and the plasma half-life of the terminal phase did not differ between the two groups. In the elderly but not in the young subjects the calculated endogenous creatinine clearance was closely correlated with the CL (r=0.90, P〈0.001), thereby emphasizing the importance of the kidney in the metabolic clearance of ANP in the elderly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280134
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  • 15
    Electronic Resource
    Electronic Resource
    Interaction of talinolol and sulfasalazine in the human gastrointestinal tract (1992)
    Springer
    European journal of clinical pharmacology 42 (1992), S. 461-462 
    Details
    ISSN: 1432-1041
    Keywords: Talinolol ; Sulfasalazine ; β-adrenoceptor-blocking drugs ; absorption ; drug interaction ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The absorption of talinolol (TA) 50 mg was investigated without and together with the co-administration of sulfasalazine (SASP) 4 g in 11 healthy young volunteers, in order to clarify gastrointestinal transit of TA. Without SASP, the tmax of TA was 2.8 h, Cmax was 112 ng·ml−1 and the half life was 12 h; the AUCo-t was 958 ng·ml−1·h. In the case of concomitant administration of SASP, TA was found only in serum from 3 individuals, with a Cmax of 23 ng·ml−1 and a mean AUCo-t of 84 ng·ml−1·h. TA was not detectable in 5 subjects and it was at the limit of detection (2 ng·ml−1) in 3 subjects. Pharmacokinetic analysis was not possible in any of those individuals. The reason for the interaction appears to be the adsorption of TA by SASP. An interval of 2–3 h should elapse between giving SASP and other drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280137
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  • 16
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    Electronic Resource
    Dantrolene inhibits halothane-induced membrane reorganization A study using 31P-NMR and differential scanning calorimetry (1992)
    Springer
    European biophysics journal 21 (1992), S. 13-19 
    Details
    ISSN: 1432-1017
    Keywords: Halothane ; Dantrolene ; DPPC ; 31P-NMR ; DSC ; Model membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The action of the relaxing agent dantrolene on dipalmitoylphosphatidylcholine (DPPC) model membranes in the presence and absence of the general anesthetic halothane has been investigated by DSC and 31P-NMR. Dantrolene has a weak effect on both the thermodynamic and NMR parameters of the pure model membrane. When halothane is present in the system, the relaxing agent acts to counterbalance the strong anesthetic-induced membrane pertubation. This is reflected in DSC experiments by a change of the enthalpy variation (ΔH) and of the main gel-to-fluid phase transition temperature (Tc) towards the values of the pure lipid system. The amount of halothane-induced small tumbling vesicles, as detected by 31P-NMR by the superposition of an isotropic line on a lamellar-type powder spectrum, is considerably reduced upon dantrolene addition. This means that the relaxing agent “cures” the membrane de-structuring action promoted by halothane. Membranes first treated with dantrolene are also protected from the halothane perturbation. So, the relaxing agent is both “curative” and “preventative” against halothane. The optimum effect is obtained for 1 dantrolene molecule per ca 34 halothane molecules. The mechanisms of action were discussed in relation to membrane fluidity.
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    URL: http://dx.doi.org/10.1007/BF00195439
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  • 17
    Electronic Resource
    Electronic Resource
    Somewhere between fiction and reality (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 51-70 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; solid-state reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurde der Einflu\ verschiedener experimenteller Bedingungen (z.B. Probenmasse, Atmosphäre, Aufheizgeschwindigkeit) auf die Zersetzung von NH4VO3, CaCO3 und V2O5 untersucht. Die Ergebnisse zeigen eindeutig, da\ Reaktionsweg und kinetische Parameter in Wirklichkeit nicht die einzelne Verbindung charakterisieren, sondern eher die Kombination von experimentellen Bedingungen und untersuchter Verbindung. Hierdurch ist es meistens unmöglich, “Standardbedingungen≓ zur Berechnung kinetischer Parameter zu wählen, da unter verschiedenen Umständen ganz andere Reaktionswege beschritten werden können.
    Notes: Abstract The influence of various experimental conditions such as sample weight, atmosphere and heating rate on the decomposition of NH4VO3, CaCO3 and V2O5 has been investigated. Results obtained clearly indicate that the course of the reactions and — in turn — the kinetic parameters, are not intrinsic to the particular compound and that they characterize rather the combination of experimental conditions and investigated compound. Such a situation makes it almost impossible to choose ‘standard conditions’ for the calculation of kinetic parameters, because under different circumstances quite different reaction-pathways can occur.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02109108
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  • 18
    Electronic Resource
    Electronic Resource
    Possibilities of two non-isothermal procedures (temperature- or rate-controlled) for kinetical studies (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 71-87 
    Details
    ISSN: 1572-8943
    Keywords: CRTA ; kinetics ; TA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird die Anwendbarkeit von herkömmlicher Thermoanalyse (TA) und geschwindigkeitsgesteuerter Thermoanalyse (CRTA) bei kinetischen Untersuchungen diskutiert. Die TA Technik kann eine zuverlässige kinetische Information und sinnvolle kinetische Parameter besonders bei Feststoffumsetzungen liefern. Die CRTA Technik ist andererseits mehr für Zersetzungsprozesse geeignet, bei denen ein oder mehrere Gase freigesetzt werden. Für beide Techniken wird eine einheitliche und geeignete Methode zu kinetischen Analyse vorgeschlagen. Als Beispiel wird diese Methode zur Analyse des Kristallisationsprozesses von Chalkogenidgläsern sowie der Zersetzung von Dolomit angewendet.
    Notes: Abstract The applicability of both conventional Thermal Analysis (TA) and Controlled Rate Thermal Analysis (CRTA) for kinetic analysis is discussed. It is shown that TA method can give a reliable kinetic information and meaningful kinetic parameters especially for solid state transformation. On the other hand the CRTA method is more suitable for decomposition process where one or more gasses are evolved. A consistent and reliable method of kinetic analysis is proposed for both techniques. This method is illustrated to analyze the crystallization process of chalcogenide glass and the decomposition of dolomite.
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    URL: http://dx.doi.org/10.1007/BF02109109
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  • 19
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    Thermodynamic and kinetic properties of hydrogen adsorption on thin iron layers (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 1999-2003 
    Details
    ISSN: 1572-8943
    Keywords: calorimetry ; hydrogen adsorption ; kinetics ; thermodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels kalorimetrischer und volumetrischer Messungen im Temperaturbereich von 298 bis 363 K wurden die thermodynamischen Eigenschaften der Wasserstoffadsorption an Eisenschichten untersucht. Die kinetischen Eigenschaften wurden mit Hilfe der Dekonvulotion kalorimetrischer Thermogramme ermittelt und mit Literaturangaben zum Haftkoeffizienten verglichen.
    Notes: Abstract Thermodynamic properties of hydrogen adsorption on iron layers evaporated under UHV conditions have been determined from calorimetric and volumetric measurements over the temperature range from 298 K to 363 K. Kinetic properties have been determined with the help of deconvolution of calorimetric curves and compared with the literature data on the sticking coefficient.
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    URL: http://dx.doi.org/10.1007/BF01979610
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  • 20
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    Thermogravimetric analysis of ZnCl2 catalyzed degradation of PVC (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2349-2357 
    Details
    ISSN: 1572-8943
    Keywords: dehydrochlorination process ; kinetics ; PVC ; ZnCh catalyzed degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels TG wurden die kinetischen Parameter des Dehydrochlorierungsprozesses (DHCL) von PVC und von mit verschiedenen Mengen von ZnCl2 versetztem PVC bestimmt. Diese Werte wurden mit denjenigen verglichen, die man bei der spektroskopischen Analyse der Zersetzung von ZnCl2-haltigen PVC-Filmen bei verschiedenen Temperaturen im sichtbaren UV-Bereich erhalten hatte. Die Werte der scheinbaren Aktivierungsenergie (E a) sinken mit zunehmendem ZnCl2-Gehalt und die hier erhaltenen Werte sind vergleichbar gut mit denen der vorangehenden Arbeit. Der katalytische Effekt von ZnCl2 auf PVC DHCL-Vorgänge wurde erklärt.
    Notes: Abstract The kinetic parameters of dehydrochlorination (DHCL) process of PVC and PVC mixed with different amount of ZnCl2 have been determined by using thermogravimetric analysis. These values have been compared with those obtained by using UV-visible spectroscopic analysis of PVC film containing ZnCh degraded at different temperatures. The values of apparent activation energy (E a) decreases with the increase of the amount of ZnCl2 and the values obtained in the present work are in reasonable comparison with previous works. The catalytic effect of ZnCl2 on PVC DHCL process is explained here.
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    The use of differential scanning calorimetry in chemical education (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 455-462 
    Details
    ISSN: 1572-8943
    Keywords: chemical education ; DSC ; polyethylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird ein überblick über die Leistungsfähigkeit von DSC in der Chemieausbildung, sowohl in der Hochschul-als auch in der Postgraduate-Phase vermittelt. Es wird ein Weg aufgezeigt, wie die Einführung von DSC in der Chemieausbildung erleichtert werden kann. Die ausführliche Beschreibung eines Hochschulexperimentes, das Schmelzverhalten von ultrahochmolekularem Polyethylenfiber wird gegeben. Es wird gezeigt, da\ derartige Experimente geeignet sind, verschiedene chemische und physikalische Vorgänge leicht demonstrieren zu können.
    Notes: Abstract An overview is given of the potential of DSC in chemical education, both in the under-graduate and in the graduate phase. The way in which the introduction of DSC in chemical education is facilitated, is outlined. A comprehensive description is given of a graduate experiment, the melting behaviour of ultra-high molecular weight polyethylene fiber. It is shown that, using such an experiment, various chemical and physical processes in substances can be easily demonstrated.
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    Hydration studies of modified OPC pastes by differential scanning calorimetry and thermogravimetry (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 495-504 
    Details
    ISSN: 1572-8943
    Keywords: cement hydration ; DSC ; TG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Bei der Untersuchung von Zement und des Einflusses von Additiven auf das Hydratationsverhalten von Zement finden thermoanalytische Methoden eine breite Anwendung. Der effektivste und meistbenutzte Beschleuniger für die Hydratation von Zement ist Calciumchlorid, aber die Ergebnisse hängen stark von der Dosiergeschwindigkeit ab. In vorliegender Studie wird mittels DSC-, TG- und Röntgendiffraktionsmethoden der Einflu\ der Dosierung von Calciumchlorid auf das Hydratationsverhalten von verschieden alten OPC-Zementbreiproben untersucht. Die Ergebnisse wurden in Bezug auf die relativen Mengen Calciumhydroxid und das gebildete Gesamtreaktionsprodukt gewertet. Bei Dosen von mehr als 1% Calciumchlorid konnte als Hydratationsprodukt Chloraluminat festgestellt werden. Sind Monochloraluminat und das Calciumaluminathydrat C4AH13 in geringen Mengen vorhanden, kann man zwischen den beiden mittels Röntgendiffraktion nicht unterscheiden. Thermoanalytische Methoden erwiesen sich als effektives Hilfsmittel bei der Charakterisierung der Produkte der Hydratation in Gegenwart von Chlorid.
    Notes: Abstract Thermal methods are used extensively in investigating cements and effects of additives on their hydration behaviour. Calcium chloride is the most effective and widely used accelerator for cement hydration, but the result is largely dependent on the rate at which it is added. In this study the influence of calcium chloride dosage on the hydration behaviour of OPC pastes aged for different periods has been investigated by means of differential scanning calorimetry (DSC), thermogravimetry (TG) and X-ray diffraction (XRD) methods. The results are discussed in relation to the relative amounts of calcium hydroxide and total reaction product formed. Chloroaluminate was a product of hydration in the samples dosed with greater than 1% calcium chloride. XRD was unable of itself to differentiate between monochloroaluminate and the calcium aluminate hydrate C4AH13 when present in small amounts. Thermal methods proved effective in characterising the products of hydration in the presence of chloride.
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    Isothermal bulk polymerization ofp-alkylaryl methacrylates by DSC (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 709-713 
    Details
    ISSN: 1572-8943
    Keywords: enthalpy of polymerization ; free radical polymerization ; kinetics ; p-alkylphenyl methacrylates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels DSC wurden im Temperaturbereich 348–373 K Reaktionsweg und Kinetik der radikalischen Raumpolymerisation vonp-Alkylphenylmethacrylaten mit AIBN Initiator untersucht. Dabei wurden die Polymerisationsenthalpie, der Monomerrest-gehalt als auch die Geschwindigkeitskonstanten und die Aktivierungsenergien der Gesamt-reaktion bestimmt. Ähnliche Werte für die Gesamtgeschwindigkeitskonstanten weisen darauf hin, daß die relativ kleinen Alkylsubstituenten inp-Stellung des Phenylringes die Polymerisationsgeschwindigkeit nur in sehr kleinem Maße — wenn überhaupt — beeinflussen.
    Notes: Abstract The course and kinetics of free radical polymerization in bulk ofp-alkylphenyl methacrylates with AIBN initiator were studied by DSC, in the temperature range 348–373 K. The enthalpy of polymerization, the residual monomer content, as well as the overall reaction rate constants and the activation energies were determined. The similar values of the overall rate constants indicate that the relatively small alkyl substituents inp-position of the phenyl ring affect the polymerization rate to a very small, if any, extent.
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    The determination of a complex kinetic expression of oil shale pyrolysis using combined non-isothermal and isothermal TG (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 729-738 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; oil shale pyrolysis ; TG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die im allgemeinen benutzte Kinetikgleichung in der Thermoanalyse von Ölschieferpyrolyse wurde auf der Grundlage einer einfachen kinetischen Gleichung erster Ordnung der Kerogenzersetzung erhalten. Mittels nichtisothermer (NI) oder isothermer (I) TG kann sowohl die Aktivierungsenergie als auch die Reaktionsgeschwindigkeitskonstante der Ölschieferpyrolyse bestimmt werden. Die unter Anwendung von NI oder I ermittelten kinetischen Parameter ermöglichen jedoch keine gute Voraussage des Kerogenumsatzes bei anderen Bedingungen. Es werden hier die Vergleichsergebnisse aus NI- bzw. I-TG von verschiedenen Ölschiefern als auch die Auswirkungen auf die sogenannte kombinierte nichtisotherme und isotherme TG (NI/I) besprochen. Die erhaltenen Ergebnisse zeigen, daß ein Mechanismus angenommen werden muß, der auf einem komplexen Reaktionsschema aus mehr als aus einer einfachen Reaktion basiert.
    Notes: Abstract The kinetic expression commonly used in the thermal analysis of oil shale pyrolysis was derived on the basis of a simple first order kinetic equation of kerogen decomposition. The activation energy, as well as the reaction rate constant of oil shale pyrolysis could be determined by using non-isothermal (NI) or isothermal (I) TG. However, the kinetic parameters determined by using either NI or I did not enable the good prediction of the kerogen conversion at other conditions. The comparative results of the NI and I-TG of different oil shales are discussed in the study, as well as the effects of the so-called combined non-isothermal and isothermal TG (NI/I). The obtained results indicate that a mechanism must be postulated based on a complex reaction scheme which involves more than one simple reaction.
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    Thermal decomposition of silver cyano complex and characterization its decomposition products by ETA, DSC, DTA and TG (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 789-796 
    Details
    ISSN: 1572-8943
    Keywords: ETA ; DSC ; DTA ; silver cyano complex ; TG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels DTA und TG wurde [Phenyl2I][Ag(CN)2] untersucht in im festen Zustand bei Erhitzen in einer Argonatmosphäre bis 160°C als thermisch stabil befunden. Beim Erhitzen auf höhere Temperaturen erfolgt eine Zersetzungsvorgang, wobei flüchtige Produkte wie z.B. [Phenyl]I, [Phenyl]NC und (CN)2 entstehen. Bei Erhitzen auf 500°C erhält man metallisches Silber. Die festen Zwischen- und flüchtigen Produkte wurden mittels IR-Spektroskopie untersucht. Anhand der DTA- und ETA-Untersuchungen konnte festgestellt werden, daß bei Erhitzen und Abkühlen unterhalb 100°C reversible Einphasenumwandlungen stattfinden. Bei Erhitzen über 100°C schmilzt die Probe (SchmelzpunktT m=135°C). Die Schmelzenthalpie wurde mittels DSC ermittelt (H=−28 kJ/mol). Mit Hilfe von ETA wurde der Unordnungsgrad des Zersetzungsendproduktes geschätzt. Der Wert der Aktivierungsenergie für die Radondiffusion im Temperaturbereich 720°–500°C beträgt 32,6 kJ/mol.
    Notes: Abstract It was found by DTA and TG that [Phenyl2I][Ag(CN)2] in the solid state is chemically stable on heating in argon up to 160°C. During heating to higher temperatures it decomposes, forming volatile products such as [Phenyl]I, [Phenyl]NC and (CN)2 [1]. After heating the sample to 500°C metallic silver resulted. The volatile and intermediate solid products were analysed by IR-spectroscopy. It was found by means of DTA and ETA that an isophase reversible transition takes place when the sample is heated and cooled, not higher than 100°C. At heating higher than 100°C the sample melts (melting pointT m=135°C). The enthalpy melting was determined by means of DSC (ΔH=−28 kJ·mol−1). By means of ETA the disorder degree of the final decomposition product was estimated. The value of the activation energy of radon diffusion in the temperature range 720°–500°C equals 32.6 kJ·mol−1.
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    On the maximum reaction rate and inflexion points on the DTG curve (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 721-728 
    Details
    ISSN: 1572-8943
    Keywords: kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es werden einige theoretische Überlegungen bezüglich des Einflusses der Form der Konversionsfunktionf(α) auf die Werte der Konversionsrate bei maximalen Reaktionsgeschwindigkeiten (αmax) sowie auf Inflexionspunkte (α∞) der DTG-Kurve angestellt. Die erhaltenen Gleichungen sind unabhängig von der Form vonf(α) durch eine all-gemeine Gültigkeit charakterisiert.
    Notes: Abstract The authors present some theoretical considerations concerning the influence of the form of the conversion functionf(α) on the values of the degree of conversion corresponding to the maximum value of the reaction rate (αmax) as well as on the inflexion points (αinf) of the DTG curve. The obtained equations are characterized by a general validity no matter the form off(α).
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    DSC and X-ray study of structure and phase transitions of low molecular compounds incorporated into crazes (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 1311-1322 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; low molecolar compounds ; phase transitions ; polymers ; X-ray
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels DSC- uns SAXS-Techniken wurden die Orientierung, Phasenzusammensetzung und Phasenumwandlungen einer Reihe von langkettigen niedermolekularen Verbindungen (LMC) wie z.B. Heneikosan, Zetylalkohol und normalen Fettsäuren untersucht, die in porösen Strukturen (Haarrissen) von in flüssigem Medium ausgerichteten polymeren Matrizen eingebracht wurden. Es konnten verschiedene LMC-Kristallit-TVpen in Haarrissen von polymeren Matrizen beobachtet werden. Es wurde gezeigt, daß der LMC-Phasenzustand in Haarrissen durch eine höhere Stabilität der Hochtemperatur-Polymermodifikationen charakterisiert ist. Die LMC Schmelztemperatur in Haarrissen nimmt im allgemeinen ab, genauso wie die Schmelzenthalpie (Wärme) und die Entropie. Der Grund für die beobachteten Veränderungen der LMC-Eigenschaften liegt in der großen Dispersität (40–100 nm) der LMC-Partikel in den Haarrissen, woraus sich ein sichtbarer Anstieg der Polymer/LMC Grenzflächeneinwirkung auf die grundlegenden thermodynamischen Parameter des untersuchten Systemes ergibt.
    Notes: Abstract Orientation, phase composition and phase transitions of a series of long chain low molecular weight compounds (LMC), such as heneicosane, cetyl alcohol, normal fatty acids, introduced into porous structure (crazes) of polymeric matrices oriented in liquid medium have been studied by means of DSC and SAXS techniques. Different types of LMC crystallites orientation in crazes of polymeric matrices have been observed. LMC phase state in crazes is shown to be characterized by higher stability of high-temperature polymer midifications. LMC melting temperature in crazes usually decreases as well as melting enthalpy (heat) and entropy. The origin of LMC properties changes observed is high dispersity (40–100nm) of LMC particles in crazes resulting in a marked growth of polymer/LMC interface influence on principal thermodynamic parameters of the systems studied.
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    The effect of water vapour pressure on the thermal dehydration of yttrium formate dihydrate (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 1793-1799 
    Details
    ISSN: 1572-8943
    Keywords: hydrated salts ; kinetics ; thermal dehydration ; yttrium formate dihydrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels isothermer Gravimetrie und bei verschiedenen Wasserdampfdrücken zwischen 5×10−4 und 8 Torr wurde die Kinetik der thermischen Dehydratation von Yttriumformiat-Dihydrat untersucht. Die Dehydratation wird als dreidimensionale Phasengrenzreaktion R3 beschrieben. Dabei wurde ein ungewöhnlicher Einfluß des athmosphärischen Wasserdampfdruckes auf die Dehydratationsgesch windigkeit beobachtet: mit steigendem Wasserdampfdruck wächst die Geschwindigkeit zunächst ebenfalls an, durchquert ein Maximum und sinkt dann nach und nach auf einen konstanten Wert ab. Diese Erscheinung ähnelt dem Smith-Topley-Effekt. Der Mechanismus dieser Erscheinung kann auf der Grundlage der Kristallinität der dehydratierten Produktephase diskutiert werden.
    Notes: Abstract The kinetics of the thermal dehydration of yttrium formate dihydrate was studied by means of isothermal gravimetry under various water vapour pressures from 5×10−4 to 8 torr. On the whole, the dehydration was described as the three dimensional phase boundary reaction, R3. An unusual dependence of the rate of dehydration on the atmospheric water vapour pressure was observed: with increasing water vapour pressure, the rate increased at first, passed through a maximum, and then decreased gradually to a constant value. These phenomena were similar to the Smith-Topley effect. The mechanism of the phenomena can be described on the basis of the crystallinity of the dehydrated product phase.
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    URL: http://dx.doi.org/10.1007/BF01974674
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    Flash calcination of kaolinite studied by DSC, TG and MAS NMR (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2053-2065 
    Details
    ISSN: 1572-8943
    Keywords: calcination ; high temperature reactions ; kaolinite ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Strukturelle Veränderungen bei der Dehydroxylierung von Kaolinit wurden durch die Anwendung einer Blitz-Kalzination untersucht, um kinetisch eingefrorene Kalzinationsprodukte zu erhalten. Der Prozentsatz der Dehydroxylierung wurde durch Veränderung der Verweilzeit im Ofen, durch Ofentemperatur und/oder Heizgeschwindigkeit modifiziert. Diese Kalzinationsbedingungen beeinflußten zwar die Reaktionskinetik, aber die Produkte hingen nur vom Ausmaß der Dehydroxylierung ab. Abweichungen bei Lage und Enthalpie der endothermen Umwandlung zu Metakaolinit und die exotherme Hochtemperaturreaktion von Metakaolinit wurden mittels DSC der Blitz-Kalzinationsprodukte verfolgt und in Beziehung zur Thermogravimetrie gebracht. 27Al Magic-Angle-Spinning NMR Spektren bei hohen magnetischen Feldstärken und Drehgeschwindigkeiten erlauben es, die Reaktion von Kaolinit zu verfolgen und liefern neue Informationen über die Natur der bei der Dehydroxylierung gebildeten Substanzen.
    Notes: Abstract The structural changes occurring during the dehydroxylation of kaolinite have been followed using flash calcination to produce kinetically frozen calcines. The percentage of dehydroxylation was varied by changing the furnace residence time or temperature and/or heating speed. These calcination conditions affected the reaction kinetics, but the products depended only on the extent of dehydroxylation. Changes in the position and enthalpy of the endothermic transformation to metakaolinite and the high temperature exothermic reaction of metakaolinite have been followed using Differential Scanning Calorimetry of the flash calcines and related to Thermogravimetry. 27Al magic-angle-spinning NMR spectra, at high magnetic fields and spin rates, enabled the reaction of kaolinite to be monitored and provides new information on the nature of the species formed in the course of dehydration.
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    Simultaneous thermal analyses for thermal dissociation studies on ZrO2 (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2129-2135 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; thermal dissociation ; ZrO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Im Temperaturintervall von 300 K bis 2670 K wurde im Hochvakuum und bei verschiedenen Aufheizgeschwindigkeiten das thermische Verhalten von Zirkoniumoxid ZrO2 untersucht. Die Experimente wurden mit Hilfe eines schweizer Universal Mettler Thermoanalysators, ausgerüstet mit einem SHT Super-Hochtemperatur-Ofen, ausgeführt. Flüchtige Produkte wurden simultan dazu mit einem Massenspektrometer QMG-101 der Balzers-Company analysiert. Die Auswertung der durch aufgezeichneten TG-, DTG-, DTA- und EGA-Kurven zeigt den komplexen Charakter des untersuchten Prozesses. Die Elementarschritte der Gesamtreaktion wurden definiert und berücksichtigt. Weiterhin wurde der Mechanismus der Thermodissoziation von ZrO2 auch in Abhängigkeit von der Aufheizgeschwindigkeit diskutiert.
    Notes: Abstract The behaviour of zirconium oxide ZrO2 during its heating in the temperature range 300–2670 K under high-vacuum conditions and at different heating rates has been studied. The experiments were performed with a Swiss made Universal Mettler thermoanalyser equipped with a super-high-temperature furnace SHT. Volatile products were analyzed simultaneously by means of a Balzers QMG-101 mass spectrometer. An analysis of the TG, DTG, DTA and EGA curves recorded simultaneously has shown the complex character of the studied process. The elementary steps of the overall process were defined and taken into consideration. The mechanism of the thermal dissociation reaction of ZrO2 as function of the hearing rate was discussed too.
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    Lattice energy of organic ionic crystals and its importance in analysis of features, behaviour and reactivity of solid-state systems (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2195-2210 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; lattice energy ; solid-state systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird eine allgemeine Methode zur theoretischen Ableitung der Kristallgitterenergie von ionischen Verbindungen, insbesondere von Verbindungen mit einatomigen Ionen beschrieben. Anschließend werden die Möglichkeiten einer theoretischen Voraussage der Gitterenergie komplexer organischer und anorganischer Ionenverbindungen diskutiert. Zuletzt wird die Bedeutung der Gitterenergie bei der Untersuchung der Eigenschaften und des Verhaltens von Feststoffsystemen im Zusammenhang mit der Aussicht auf die Entwicklung eines Modelles zur Beschreibung der Kinetik von Feststoffprozessen gezeigt.
    Notes: Abstract A general approach to the theoretical evaluation of the crystal lattice energy of ionic substances, particularly those composed of monoatomic ions, is outlined in detail. Subsequently, the possibilities of theoretical prediction of the lattice energy of complex organic and inorganic ionic substances are discussed. Lastly, the importance of the lattice energy in examinations of the properties and behaviour of solid-state systems, is treated, together with the prospects of developing a model describing the kinetics of solid-state processes.
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    Thermal Analysis Studies on Isopropylnitrate (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 9-19 
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    ISSN: 1572-8943
    Keywords: ARC ; DSC ; HFC ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Isopropylnitrate (IPN) is described as a detonable material used in propellants and explosives. While there is considerable information available on its sensitivity and compatibility with other materials, very little is known about its thermochemical properties. This paper will describe the results obtained from some DSC, heat flux calorimetry (HFC) and accelerating rate calorimetry (ARC) measurements. The ASTM DSC method using a hermetic aluminum pan having a lid with a laser-produced pin hole was used to determine the vapour pressure of IPN1. Results calculated from an Antoine equation are in substantial agreement with those determined from DSC measurements. From the latter measurements, the enthalpy of vaporization was determined to be 35.32±0.62 kJ mol−1. Attempts to determine vapour pressures above about 0.8 MPa resulted in significant decomposition of IPNg. The enthalpy change for decomposition in sealed glass systems was found to be -3.43±0.09 kJ g−1 and -3.85±0.03 kJ g−1, respectively from DSC and HFC measurements on IPN1 samples loaded in air. Slightly larger exotherms were observed for the HFC results in air than those in inert gas, suggesting some oxidation occurs. In contrast, no significant difference in the observed onset temperature of about 150°C was observed for both the HFC and ARC results. From DSC measurements, an Arrhenius activation energy for decomposition of 126±4 kJ mol−1 was found. These measurements were also conducted in sealed glass systems and decomposition appeared to proceed primarily from the liquid phase.
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    Apparent Activation Energies of the Non-isothermal Degradation of Eva Copolymer (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 67-76 
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    ISSN: 1572-8943
    Keywords: activation energy ; DSC ; ethylene-vinyl acetate copolymer ; TG ; TG/IR ; thermal degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract When ethylene-vinyl acetate copolymer, EVA, is heated, a two-stage thermal degradation occurs following its melting. The vinyl acetate content of the copolymer was determined to be 43.8% by using TA 2950 and TA 2050 thermogravimetric instruments. TG/FTIR was used to detect the evolved gas. Acetic acid and trans-1-R-4-R'-cyclohexane were the main products evolved from EVA in the first and second stage, respectively. The apparent activation energies were determined for both stages by differential methods.
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    Crystallization Kinetics of Polypropylene-polyethylene-based Copolymers (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 57-65 
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    ISSN: 1572-8943
    Keywords: artificial ageing ; DSC ; dynamic crystallization ; isoconversional method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A crystallization kinetics analysis of several polypropylene-polyethylene (PP-PE), PP-rich copolymers was made by means of differential scanning calorimetry. The crystallization was studied via calorimetric measurements at different cooling rates. Several additives were added to the base material. Some test samples were subjected to artificial ageing processes. A modified isoconversional method was used to describe the crystallization process under non-isothermal conditions. The value of the Avrami parameter was determined for primary and secondary crystallization.
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    URL: http://dx.doi.org/10.1023/A:1010123819994
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    Kinetics of Thermal Decomposition of Mixed Ligand Trinuclear Compound of Cadmium(II) (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 233-241 
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    ISSN: 1572-8943
    Keywords: cadmium(II) atom ; kinetics ; non-isothermal decomposition ; Schiff-base compound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal C81H78N12O6Cd3 was synthesized and its structure was determined by single crystal X-ray diffraction method. The complex crystallizes in the monoclinic system space group P21/n with cell parameters, a=15.959(4) Å, b=26.222(3) Å, c=25.907(6) Å, β=101.60(2)°. The non-isothermal kinetics of the crystal was studied by use of non-isothermal TG and DTG curves. The kinetic parameters were analyzed by means of integral and differential methods, and mechanism functions of the thermal decomposition reaction for its second step were proposed. The kinetic equation of thermal decomposition is expressed as: dα/dt=Aexp(-E/RT)1.5(1-α)4/3[1/(1-α)1/3-1]−1. The average values of E(kJ mol−1) and lnA/s−1 are 339.25, 43.95, respectively.
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    Re-examination of the Kinetics of the Thermal Dehydroxylation of Goethite (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 301-309 
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    ISSN: 1572-8943
    Keywords: dehydroxylation ; goethite ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics of thermal dehydroxylation of aluminuous goethites [1] synthesised from a ferrous salt has been re-examined using the general reaction order kinetic law. The utilised data processing was based on the procedures employed by dissolution kinetics. Recalculation of the activation energies EA of the dehydroxylation yielded the values 130, 132, 128, and 123 kJ mol−1 for pure goethite, goethite with 10, 20, and 30 mol% Al substitution, respectively. The values of EA are in a good agreement with those given for goethite in literature. The EA values are linearly related with the chemically bound excess H2O/OH− in the crystal lattice that is apparently influenced by Al substitution.
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    Kinetic Analysis of Thermogravimetric Data XXXII. DSC Study of Some [Co(Diox·H)2(amine)2]X and H[Co(Diox·H)2(N3)2] Type Complexes with Alicyclic α-dioximes (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 311-320 
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    ISSN: 1572-8943
    Keywords: dioximine complexes of Co ; DSC ; kinetic compensation effect ; kinetic parameters of thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract 14 mixed Co(III) dioximine chelates of the types [Co(Diox·H)2(amine)2]X (X = Br, I, NO3, ClO4) and H[Co(Diox·H)2(N3)2], respectively (Diox·H2-1,2-cyclohexane dione dioxime (nyoxime), 1,2-cycloheptane dione dioxime (heptoxime) 1,2-cyclooctane dione dioxime (octoxime) were obtained and their thermal decompositions were studied in an argon atmosphere. After the dehydration of the crystallohydrates, both types of complexes exhibit 3 decomposition stages. For the [Co(Diox·H)2(amine)2]X type complexes (X = Br, I) the first endothermal stage is the substitution of an amine molecule for the external sphere anion and this process is followed by two exothermal decomposition stages. With H[Co(Diox·H)2(N3)2] type complexes the first and third processes are relatively slow, but the second process is very fast, corresponding to a vertical portion of the TG curves. From the TG curves kinetic parameters were derived for 11 processes and the validity of a non-linear compensation law was observed.
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    Thermogravimetric Analysis of Cobalt(II)-dothiepin Complexes (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 841-849 
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    ISSN: 1572-8943
    Keywords: cobalt(II)-dothiepin ; kinetics ; TG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The complexes of cobalt(II) with dothiepin (DOT) hydrochloride have been studied for kinetics of thermal degradation by thermogravimetric analysis (TG) and derivative thermogravimetric studies (DTG) in a static nitrogen atmosphere at a heating rate of 10° C min−1. A general mechanism of thermal decomposition is advanced involving dehydration and decomposition process for both organic and inorganic ligands. The thermal degradation reactions were found to proceed in three steps having an activation energy in the range 6.75–170 kJ mol−1. Thermal decomposition kinetics parameters were computed on the basis of thermal decomposition data.
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    Calorimetric Investigations of Some Phases in the System Sodium Fluoride - Aluminium Fluoride (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 51-57 
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    ISSN: 1572-8943
    Keywords: DSC ; enthalpies ; NaAlF4 ; Na5Al3F14
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Beside the two well-known minerals cryolite, Na3AlF6, and chiolite, Na5Al3F14, the binary system NaF-AlF3 also contains a third compound, NaAlF4, sodium tetrafluoroaluminate. Solid NaAlF4 has been prepared from its vapour under controlled conditions. The stability of NaAlF4 has been investigated by differential scanning calorimetry. It is shown that the disproportionation of the compound: 5NaAlF4(s)=Na5Al3F14(s)+2AlF3(s) takes place at considerable rate between 700 and 900 K. The enthalpy of this reaction is calculated and found to be -66.9 kJ. Enthalpies of the two solid state transitions α-Na3AlF6 → β-Na3AlF6 and α-AlF3 → β-AlF3 have also been measured and new values are reported. The enthalpy of formation of chiolite, Na5Al3F14, at 900 K has been recalculated from enthalpy increment data obtained by drop calorimetry. A value of ΔH900 o = -7513.6±12.0 kJ mol-1 has been obtained. This value is in disagreement with the recommended value given in JANAF Thermochemical Tables given at 900 K ΔHf o = -7559.2 kJ mol-1.
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    Gegeneration of Deactivated β-Zeolite by Coke Oxidation (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 297-303 
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    ISSN: 1572-8943
    Keywords: β-zeolite ; coke ; cumene ; kinetics ; regeneration ; TG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An accurate description of coke burn off is obtained from a catalyst based on β-zeolite and used for benzene alkylation with propylene giving cumene by using the thermogravimetric technique. A simple empirical kinetic model was successfully applied to interpolate the data of thermogravimetric analysis performed on samples after partial burn off. Different temperatures, partial pressures of oxygen and gas flow rates were the variables studied in order to calculate the apparent rates and the activation energy for the coke oxidation reaction and to outline the best conditions for the industrial regeneration procedure of our proprietary catalyst PBE-1 for cumene synthesis. Combining the unusually long lifetime per reaction cycle with the optimized regeneration procedure leads to an outstanding overall catalyst life.
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    The Fe-Ni Distribution Between Pentlandite and Monosulfide Solid Solution Equalized at Low Temperature (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 925-929 
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    ISSN: 1572-8943
    Keywords: DSC ; equilibrium ; Fe-Ni distribution ; monosulfide solid solution ; pentlandite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two mixtures of pentlandite and the monosulfide solid solution (mss) have been synthesized. The bulk compositions of the samples are Fe6Ni3S8 and Fe3Ni6S8. Differential scanning calorimetry detected exothermic process in the samples under heating. The process takes place in temperature range between phase transition in the mss (near 400 K) and 690 K and is governed by diffusion. X-ray powder diffraction has showed that equilibrium Fe-Ni distribution between pentlandite and the mss is achieved after short-time heating up to 670 K.
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    Non-Isothermal Pyrolysis and Kinetics of Oil Shales (1999)
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    Journal of thermal analysis and calorimetry 56 (1999), S. 953-958 
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    ISSN: 1572-8943
    Keywords: differential scanning calorimeter ; kinetics ; oil shale ; pyrolysis ; thermogravimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In this research, non-isothermal pyrolysis behavior and kinetics of three oil shales were studied by thermal analysis methods. All the thermal effects were endothermic and no exothermic region was observed in DSC curves. When oil shales are heated in nitrogen atmosphere in TG/DTG, two different mechanisms causing loss of mass were observed. The region between ambient temperature and 500 K was distillation. The second mechanism was visbreaking and cracking and it was observed between the region 500 and 800 K. Kinetic parameters of all the samples are determined by Coats and Redfern method and the results are discussed with regard to their accuracy and the ease of interpretation.
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    Cure Kinetics of Amine Cured Tetrafunctional Epoxy Blends with Poly(Styrene-Co-Acrylonitrile) (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1033-1040 
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    ISSN: 1572-8943
    Keywords: cure kinetics ; DSC ; epoxy resin ; SAN ; thermoplastic blends
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Cure kinetics using a differential scanning calorimetry (DSC) technique were analyzed for a thermoplastic modified tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) epoxy resin cured with diaminodiphenylsulphone (DDS), an aromatic diamine. The neat resin and its blends with the poly(styrene-co-acrylonitrile) (SAN) of various compositions were studied by applying a phenomenological model proposed by Kamal. Kinetic parameters were determined by fitting experimental data. This model gives a good description of cure kinetics up to the onset of vitrification. Diffusion control was incorporated to describe the cure in the latter stages of cure. The results showed that the addition of SAN did not alter the nature of the reaction, but the reaction rates and final conversions decreased when SAN contents increase, due to reduction of mobility of the reacting species.
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    Thermal Analysis, Microcalorimetry and Combined Techniques for the Study of Pharmaceuticals (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1285-1304 
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    ISSN: 1572-8943
    Keywords: amorphous state ; combined techniques ; drug design ; drug product development ; drug substance ; drug technology ; DSC ; excipients ; failure investigations ; hydrates ; MDSC ; microcalorimetry ; pharmaceuticals ; polymorphism ; polymers ; preformulation ; process optimization ; purity ; quality control ; solvates ; stability ; sub-ambient DSC ; TG ; temperature resolved X-ray diffraction ; water interactions ; thermal microscopy ; water sorption-desorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Modern thermal analysis, microcalorimetry and new emerging combined techniques which deliver calorimetric, microscopic and spectroscopic data offer a powerful analytical battery for the study of pharmaceuticals. These techniques are very useful in all steps of development of new drug products as well as methods for quality control in production. The characterization of raw materials enables to understand the relationships between polymorphs, solvates and hydrates and to choose the proper development of new drug products with very small amount of material in a very short time. Information on stability, purity is valuable for new entities as well as for marketed drug substances from different suppliers. Excipients which vary from single organic or inorganic entity to complexes matrixes or polymers need to be characterized and properly controlled. The thermodynamic phase-diagrams are the basis of the studies of drug-excipients interactions. They are very useful for the development of new delivery systems. A great number of new formulations need proper knowledge of the behaviour of the glass transition temperature of the components. Semi-liquid systems, interactions in aqueous media are also successfully studied by these techniques.
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    Thermal Analysis, Microcalorimetry and Combined Techniques for the Study of the Polymorphic Behaviour of a Purine Derivative (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 61-73 
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    ISSN: 1572-8943
    Keywords: amorphous ; combined techniques for polymorphism ; DSC ; MKS 492 ; polymorphism ; purine ; quantitative determination ofamorphous and polymorphs ; solvent mediated transitions ; temperature resolved X-ray diffraction ; TG ; thermodynamic relation between polymorphs ; xanthine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The polymorphic behaviour of the purine derivative MKS 492 was studied with investigations of suspensions of selected samples in different solvents and of samples obtained by crystallizations. The samples were analyzed by DSC, TG and X-ray diffraction. Six different crystalline modifications called A, B, B’, C, D and E and an amorphous form were identified. Four pure crystalline modifications, A, B, C and D have been manufactured and characterized by DSC, X-ray, IR, solubilities, densities, hygroscopicity and dissolution measurements. The four forms A, C, D and E are monotrop to the form B. The form B is enantiotrop to the form B’, which revealed the highest melting point of all known polymorphs. This form B’ is only stable at high temperature. Temperature resolved X-ray diffraction was very helpful for proper interpretation of the thermal events. The melting peaks of the forms A and C and the endothermic peak corresponding to the enantiotropic transition B into B’ occur in a narrow range of temperature. The form B which is the most stable one at room temperature has been chosen for further development. Quantitative methods to determine the content of the forms A, C and D in samples of form B or to determine the content of form A, B and D in form C have been developed by using X-ray diffraction. Limits of detection are 1 or 2%. For the quantitative determination of the amorphous fraction, X-ray diffraction and microcalorimetry are compared. For high amounts of the amorphous fraction, the X-ray diffraction method is preferred because it is faster. Microcalorimetry is very attractive for levels below 10% amorphous content. The lowest limit of detection is obtained by microcalorimetry, about 1%.
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    Pre-Eutectic Densification of Calcium Carbonate Doped with Lithium Carbonate (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1461-1473 
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    ISSN: 1572-8943
    Keywords: CaCO3 ; densification ; kinetics ; Li2CO3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Pressureless sintering of CaCO3 was carried out, with Li2CO3 (from 0.5 to 8 wt%) as an additive, under different pressures of CO2. Densification occurs between 600 and 700°C. Sintering above the eutectic temperature (T〉662°C) leads to the decomposition of calcium carbonate and the materials become expanded. At 620° under 1 kPa of CO2, a relative density of 96% is reached. Li2CO3 enhances the densification process and grain growth of calcium carbonate. CO2 pressure slows down densification and grain growth kinetics. These results are explained by the influence of carbonate and calcium ion vacancies on the sintering mechanisms.
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    Comparison of Experimental Methods and Theoretical Calculations on Crystal Energies of ‘Isoenergetic’ Polymorphs of Cimetidine (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 7-22 
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    ISSN: 1572-8943
    Keywords: crystal modifications ; DSC ; Gibbs free energy function ; molecular modelling ; solution calorimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermodynamic energy relationship between two crystal modifications of cimetidine was investigated and compared with differences in their processing properties with respect to transformation from one modification to the other. The crystal energies of the two modifications A and D were found to be almost identical and therefore the polymorphs are regarded as virtually isoenergetic crystals. This statement is based on DSC measurements of the melting points and of the enthalpies of fusion for the two crystal forms, which enable the calculation of the Gibbs free energy functions. Furthermore, the statement is supported by measurements of the enthalpies of solution in two different solvents. Both DSC and solution experiments reveal a slightly higher stability of the D modification with respect to the A form. In addition, tribomechanical treatment also indicates modification D to be the more stable one, as well as the higher density of the D form. No transformation during DSC at low heating rate was found which could be used in a stability consideration. As the explicit crystal structures of the two modifications are resolved, it was possible to calculate crystal energies theoretically as well. The theoretical results showed a remarkable difference in the crystal energies at zero degree Kelvin. Furthermore, they were just contradicting experimental findings by stating A being more stable than D. Possible reasons for this discrepancy and the feasibility of today's calculation methods with respect to prediction of stability properties are discussed.
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    Polymorphism of Acrylic and Methacrylic Acid Esters Containing Long Fluorocarbon Chains and Their Polymerizability (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 631-642 
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    ISSN: 1572-8943
    Keywords: DSC ; fluorocarbon chain ; polymerizability ; polymorphic behaviors ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The molecular aggregation of acrylic and methacrylic acid esters containing long-fluorocarbon chains: 2-(perfluoroalkyl)ethyl acrylate (FFnEA) and 2-(perfluoroalkyl)ethyl methacrylate (FFnEMA) (F(CF2)nCH2CH2OCOC(X)=CH2, where X=H, CH3 and n=6, 8, 10) was investigated by differential scanning calorimetry (DSC) and temperature controlled X-ray powder diffraction measurement. These compounds exhibited some characteristic polymorphic behaviors depending on the length of fluorocarbon chain and the α-position methyl group. The solid-state polymerization by γ-ray irradiation was studied for these compounds in the various crystal forms. In the solid-state polymerization, highest polymerizability was observed in the crystal form that exists in the highest temperature region for each compound.
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    Study of Ethyl Cellulose—Benzoic Acid Interactions in Matrices for Controlled Drug Release by DSC (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 29-38 
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    ISSN: 1572-8943
    Keywords: benzoicacid ; controlled release ; DSC ; ethyl cellulose ; FTIR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The physical state of benzoic acid (BA) and its interaction with ethyl cellulose (EC) were examined in ethyl cellulose—benzoic acid matrices by Differential Scanning Calorimetry (DSC). The glass transition temperature (Tg) of EC of various matrices having BA in solid solution form (upto 27.7%) was reduced. The BA in matrices containing more than 38.9% drug exhibited distinct melting endotherms due to crystalline form. The peak temperatures of these endotherms were lowered and they broadened as the concentration was lowered. The solubility of BA increased at its melting point as compared to ambient temperature. The melting enthalpy of BA, when plotted as a function of its concentration yielded a straight line with intercept of 330 mg g−1 of matrix. This is the solubility of BA in EC at its melting temperature. Fourier Transform Infra Red Spectroscopy (FTIR) investigations confirmed that hydrogen bonding occurred between EC and BA through hydroxyl groups.
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    Thermal Behaviour and Decomposition Kinetics for Two Palladium(II) Complexes with 1-aminopyrene and its Derivative (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 383-391 
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    ISSN: 1572-8943
    Keywords: 1-aminopyrene (apyr) ; N-(2-pyridylmethylene)-1-pyrenylamine (pmpa) ; kinetics ; palladium(II)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermal decomposition studies for two palladium(II) complexes Pd(apyr)2Cl2 and Pd(pmpa)Cl2 (apyr=1−aminopyrene and pmpa=N−(2−pyridylmethylene)−1−pyrenylamine) were carried out in pure nitrogen using TG-DTG techniques. The non-isothermal kinetic parameters for the two complexes were evaluated employing the method suggested by Málek, Šesták, Koga et al. Based on the above results, thermal behaviour of the complexes were carefully discussed, which showed that not only the parameters value, but also the decomposition pattern and mechanism for complex 1 are different from complex 2.
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    Studies on the Kinetics of the First Order Autocatalytic Decomposition Reaction of Highly Nitrated Nitrocellulose (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 403-411 
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    ISSN: 1572-8943
    Keywords: first order autocatalytic reaction ; HNNC ; kinetics ; TG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics of the first order autocatalytic decomposition reaction of highly nitrated nitrocellulose (HNNC, 14.14%N) was studied by using thermogravimetry (TG). The results show that the TG curve for the initial 50% of mass-loss of HNNC can be described by the first order autocatalytic equation $$\frac{{{\text{d}}y}} {{dt}} = - 10^{16.4} \exp \left( { - \frac{{210380}} {{RT}}} \right)y - 10^{16.7} \exp \left( { - \frac{{171205}} {{RT}}} \right)y(1 - y)$$ and that for the latter 50% mass-loss of HNNC described by the reaction equations $$\frac{{dy}} {{dy}} = - 10^{16.3} \exp \left( { - \frac{{169483}} {{RT}}} \right)y\quad (n = 1)$$ and $$\frac{{dy}} {{dt}} = - 10^{16.8} \exp \left( { - \frac{{165597}} {{RT}}} \right)y^{2.61} \quad (n \ne 1)$$
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    Combination of DSC and X-ray Diffraction in the Study of the Phase Behaviour of Lipids: Mini-review (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 363-368 
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    ISSN: 1572-8943
    Keywords: DSC ; lipid ; phase behaviour ; synchrotron radiation ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The phase behaviour and phase stability of lipids are of importance in an understanding of the biological functions of cell membranes. Among a variety of physical techniques employed to study the phase behaviour and structural properties of polar lipids, differential scanning calorimetry and X-ray diffraction have proved to be successful and are the most frequently used methods. Applications involving a combination of the two techniques, particularly when synchrotron radiation is used as the light source of X-ray diffraction, are reviewed in this article.
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    Measurements of Heat of Zeolite Dehydration by Scanning Heating (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 653-662 
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    ISSN: 1572-8943
    Keywords: dehydration ; DSC ; TG ; water ; zeolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A procedure for measurement of the heat of zeolite dehydration by scanning heating has been designed. Simultaneous data on heat flow (DSC) and mass loss (TG) are required for evaluation. The heating rate depends on the experimental conditions (point-spread function, sample mass, crucible design, and calorimetric reproducibility). Dehydration measurements have three advantages as compared with the sorption procedure: i) one can investigate samples with irreversible dehydration; ii) no approximation model is needed for calculation of the partial molar heat of dehydration; and iii) the procedure is not labor-consuming. The procedure was tested on the natural zeolites heulandite, chabazite and mordenite. The results are close to those measured by the sorption procedure. The partial molar heat of dehydration was found to depend on the water content. It increases from 50 to 87 J mol−1 K−1 for heulandite, from 53 to 81 J mol−1 K−1 for chabazite, and from 51 to 71 J mol−1 K−1 for mordenite. The approximation of the heat of sorption by linear regression was found to be wrong. Detection of a ‘phase transitioN’ after this approximation has no meaning.
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    Transformation-Governed Heating Techniques in Thermal Analysis II. (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 725-739 
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    ISSN: 1572-8943
    Keywords: DDC ; DSC ; DTA ; transformation-governed TA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The described instrumental method makes it possible that the quasi-static heating technique, well applicable to thermogravimetric measurements, (see Part I of this paper) can be used in the case of DTA and DSC examinations, too. Based on the new type of curves the characteristic transformation temperatures, the whole course of the transformation in dependence of sample temperature, the extent of the enthalpy change caused by the transformation or by its partial processes can accurately be determined. The essentially greater accuracy of the measurements — in comparison to the conventional ones — is due to the quasi-static heating technique which ensures that the transformations should take place under quasi-equilibrium conditions.
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    Thermische Analyse binärer Systeme Organischer Verbindungen, die induzierte smektische Phasen bilden (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 1607-1626 
    Details
    ISSN: 1572-8943
    Keywords: binary systems of cholesteryl ; DSC ; esters ; induced smectic phases ; thermomicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Acht binäre Systeme einer homologen Reihe von Cholesterylestern (Cholesterylpropionat bis Cholesteryldecanoat) mit trans-4-Propylcyclohexyl-4-(trans-4-pentylcyclohexyl) benzoat (Licristal 1223, Merck, Darmstadt) wurden thermomikroskopisch und DSC-analytisch untersucht. In sechs Fällen wurden induzierte smektische A-Phasen mit Umwandlungspunktmaxima festgestellt. Die cholesterischen bzw. nematischen Phasen bilden kontinuierliche Reihen von cholesterischen Mischkristallen, während die festkristallinen Phasen bei allen Systemen einfache Eutektika aufweisen.
    Notes: Abstract Eight binary systems of a homologous series of cholesteryl esters (from cholesteryl propionate to cholesteryl decanoate) with trans-4-propylcyclohexyl-4-(trans-4-pentyl-cyclohexyl) benzoate (Licristal 1223, Merck, Darmstadt) were examined by thermomicroscopy and DSC analysis. In six cases induced smectic A phases with transition point maxima were observed. The cholesteric resp. nematic phases form continuous series of cholesteric mixed crystals, while the solid phases show simple eutectics.
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    Zersetzung von Phosphor-Rohrstoffen durch Säuren (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 1683-1690 
    Details
    ISSN: 1572-8943
    Keywords: kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Auf Grund der bestimmten thermokinetischen Kurven der Zersetzung von Phosphor-Rohstoffen mit Säuren wurde die Abhängigkeit des Umwandlunsgrades der einzelnen Reagenten von solchen Faktoren wie Zeit, Enthalpie u. konstante Zerlegungeschwindigkeit bestimmt.
    Notes: Abstract On the basis of the thermokinetic curves of the phosphor deposits with acids the dependence of the conversion degree upon the time, the enthalpy and the reaction rate constant were determined.
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    URL: http://dx.doi.org/10.1007/BF01979364
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    Spectroscopic and Thermal Studies on 2,4,6-trinitro Toluene (TNT) (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 173-185 
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    ISSN: 1572-8943
    Keywords: IRS ; kinetics ; mechanism ; nitro aromatic ; TA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics and mechanism of the initial stage of thermal decomposition of 2,4,6-trinitro toluene (TNT), a widely used high explosive, have been studied, together with its morphology and evolved gaseous products using thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy (IR) and hot-stage microscopy. The kinetics of the thermolysis has been followed by IR after suppressing volatilisation by matrixing and by isothermal TG without suppressing volatilisation to simulate actual user conditions. The best linearity was obtained for Avrami-Erofeev equation for n=1 in isothermal IR and also in isothermal TG. The activation energy was found to be 135 kJ mol−1, with logA (in s−1) 12.5 by IR. The effect of additives on the initial thermolysis of TNT has also been studied. Evolved gas analysis by IR showed that CO2, NO2, NO and H2O are more dominant than N2O, HCN and CO. The decomposition involves the initial rupture of the C-NO2 bond, weakened by hydrogen bonding with the labile hydrogen atom of the adjacent CH3 group, followed by the abstraction of the hydrogen atom of the methyl group by NO2, generated in the initial step.
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    Effects of Added Urea and Alkylureas on Gel to Liquid-Crystal Transitions in Doab Vesicles (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 29-35 
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    ISSN: 1572-8943
    Keywords: alkylureas ; DOAB vesicles ; DSC ; gel-liquid transitions ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The gel to liquid-crystal transition for vesicles in aqueous solution formed by dimethyldi-n-octadecylammonium bromide (DOAB) occurs at 44.7°C. Moreover, the shapes of the scans recorded by a sensitive DSC microcalorimeter are very similar when the vesicular solutions are prepared starting with solid DOAB and comparable amounts of either solid urea or solid alkylureas. Therefore, the DOAB vesicles in aqueous solution accommodate this class of solutes without marked changes in the melting temperature and the enthalpy of the transition. The contrast with effects of added surfactants and simple organic solutes such as THF and ethanol is particularly significant.
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    Thermal Decompositions of (RE)Ba2Cu3O6 (RE=Y, Nd, Er) (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 691-698 
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    ISSN: 1572-8943
    Keywords: activation energy ; kinetics ; solid-state reactions ; superconductors ; thermogravimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Thermogravimetric in situ measurements of oxygen loss from (RE)Ba2Cu3O6 samples (RE=Y, Nd, Er) heated isothermally in a relatively high dynamic vacuum were made with a Cahn RG electrobalance. Single-phase orthorhombic samples of composition (RE)Ba2Cu3O7-x (highest oxygen content) were synthesized from stoichiometric (1:2:3) mixtures of high-purity (RE)2O3, BaCO3 and CuO. The original 1:2:3 mixture was prepared by the two-stage procedure described earlier. The crystal structure of the sample in the original orthorhombic phase was controlled by the X-ray powder method (CuKα radiation) using a Stadi P Stoe diffractometer with a position-sensitive detector. The decomposition curves are described by the sum of exponential terms corresponding to rapid and slow first-order processes in which differently sized grains of the powder samples are involved. The activation energies are estimated from appropriate Arrhenius plots.
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    Thermal and Spectroscopic Study of Dehydration of Lithium Formate Monohydrate Single-crystals (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 807-816 
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    ISSN: 1572-8943
    Keywords: DSC ; hydrogen-bond ; IR ; lithium formate monohydrate ; Raman spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) of lithium formate monohydrate (LiHCOO·H2O) were performed in the temperature range 300–700 K. The DSC/TG measurements show that the dehydration process to anhydrous lithium formate (LiHCOO) is complex and occurs in two stages. The data are correlated to the structure and to the arrangement of the molecules in the crystal, including the hydrogen-bonding. Infrared transmittance and Raman spectra of this crystal are reported and commented on.
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    URL: http://dx.doi.org/10.1023/A:1010125631748
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    Thermal Decomposition of Strontium and Barium Malonates (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 789-796 
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    ISSN: 1572-8943
    Keywords: alkaline earth malonates ; DSC ; DTA ; kinetic parameters ; TG ; thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermal decomposition of strontium and barium malonates has been studied isothermally and non-isothermally employing simultaneous TG-DTG-DTA, DSC, XRD and IR spectroscopic techniques. DSC of these malonates has been recorded both in oxygen and nitrogen atmospheres. The decomposition is a single step process and the end product formed is carbonate. The energy of activation and frequency factor values for the decomposition of strontium malonate are 547 kJ mol−1 and 1041 s−1 respectively. The activation energy and frequency factor values for isothermal dehydration of barium malonate sester-hydrate are 57–111 kJ mol−1 and 107–1012 s−1 respectively and the corresponding values for decomposition from DSC are 499.5 kJ mol−1 and 1044 s−1 respectively. The higher thermal stability of strontium malonate as compared to that of barium salt is ascribed to its being anhydrous so that decomposition proceeds without restructuring. Their thermal stabilities have also been compared with that of respective oxalate salts.
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    Thermal Decompositions of the Molybdotellurates of Nickel(II) and Cobalt(II) (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 779-788 
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    ISSN: 1572-8943
    Keywords: cobalt ; dynamic and isothermal methods ; kinetics ; molybdotellurates ; nickel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Molybdotellurates [M(H2O)6]3·[TeMo6O24], with M=Ni(II) and Co(II), were synthesized and characterized by single-crystal X-ray diffraction for compound 1 and X-ray powder diffraction for compound 2, EDAX, IR, electronic spectra in the solid phase and in solution, and magnetic properties. Thermogravimetry and differential scanning calorimetry of both compounds revealed a loss of 11 water molecules through an endothermal process with ΔH=800 kJ mol−1 for the nickel compound and ΔH=833 kJ mol−1 for the cobalt compound. The residual compounds were characterized by chemical analysis, IR and XPS spectroscopy
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    Physicochemical Studies and Thermal Decomposition Kinetics of Co(II), Ni(II), Cu(II) and Zn(II) Complexes of Citronellal Anthranilic Acid (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 817-831 
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    ISSN: 1572-8943
    Keywords: kinetics ; Schiff-bases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Cobalt(II), nickel(II), copper(II) and zinc(II) complexes of two new Schiff-bases, citronellal anthranilic acid and citronellal-5-bromoanthranilic acid have been synthesized. On the basis of spectral, magnetic and thermal data, octahedral structure was assigned to all complexes [ML2(H2O)2]. Thermal decomposition of these complexes was studied by TG. Kinetic parameters, viz activation energy, E, pre-exponential factor, A, and order of reaction, n, were calculated from the TG curves using mechanistic and non-mechanistic integral equations.
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    From Precursors to Thin Films - Thermoanalytical Techniques in the Thin Film Technology (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 7-15 
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    ISSN: 1572-8943
    Keywords: ALE ; CVD ; DSC ; DTA ; EGA ; EL display ; solar cell ; sol-gel ; spray pyrolysis ; super-conductor ; TG ; thin films
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Processing thin films for advanced applications, for instance in electronics and optoelectronics, involves several steps starting from precursor synthesis and ending up with the devices. Especially when optimizing the first steps of this chain of processes, thermoanalytical techniques play an important role. The review will focus on the main chemical deposition methods (CVD, ALE, spray pyrolysis, sol-gel) giving selected examples of problem-solving by thermal analysis. The techniques discussed are TG, DTA/DSC, EGA and their combinations. High-temperature X-ray diffraction (HTXRD) is also a powerful tool for in situ studies of thin films. The examples are taken from solar cell, superconductor and flat panel electroluminescent display technologies.
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    α-β Phase Re-Transformation Kinetics in Nickel Sulphide (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 429-435 
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    ISSN: 1572-8943
    Keywords: DSC ; nickel sulphide ; TG ; toughened glass ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Nickel sulphide (NiS) was characterised using X-ray diffraction, thermal gravimetric analysis (TG) and differential scanning calorimetry (DSC). The 'as received' Millerite, stoichiometric NiS, observed to be slightly nickel deficient, was found to readily decompose in a nitrogen atmosphere at elevated temperatures (450°C max.) to the sulphur deficient Godlevskite, Ni7S6. DSC and X-ray measurements demonstrated that the high temperature form of the Godlevskite was readily stabilised at room temperature. The kinetics of the α-β re-transformation in Godlevskite were then investigated using DSC and were observed to be first order.
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    RCTA Techniques Used in Studies of Solid State Reactions in Inorganic Compounds (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 17-26 
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    ISSN: 1572-8943
    Keywords: kinetics ; reaction controlled thermal analysis ; stepwise isothermal analysis ; thermogravimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The Reaction Controlled Thermal Analysis techniques, RCTA, are very useful both in thermogravimetric and dilatometric studies. In the present paper this big family of techniques is divided into three main classes: Quasi-Isothermal techniques (QIA); Controlled Reaction Rate Thermal Analysis (CRTA) and Reaction (Event) Controlled Heating Rate Adaption. After a short presentation of these techniques and the general advantages of RCTA, two examples of kinetic studies on thermal decomposition of Ba- and Ce oxalates by using Stepwise Isothermal Analysis, SIA, introduced by the author is presented and discussed.
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    Thermochemistry of the Decomposition of Some Cobalt Compounds (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 547-552 
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    ISSN: 1572-8943
    Keywords: cobalt oxysalts ; DSC ; enthalpy of decomposition ; enthalpy of dehydration ; thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Differential scanning calorimetry (DSC) was used to determine the molar enthalpies of dehydration and decomposition of CoC2O4·2H2O, Co(HCOO)2·2H2O and [Co(NH3)6]2(C2O4)3·4H2O. The first stage of dissociation of each compound is a single-step dehydration both in air and argon atmospheres. The next stages are decomposition processes influenced by experimental parameters. The enthalpies of dehydration and decomposition vary from compound to compound in each atmosphere. The obtained data have been related to the macromechanisms proposed for the thermal decomposition and the parallel-consecutive decomposition-oxidation processes.
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    Isothermal and Non-Isothermal Kinetics When Mechanistic Information Available (1999)
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    Journal of thermal analysis and calorimetry 56 (1999), S. 783-792 
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    ISSN: 1572-8943
    Keywords: complex process ; DSC ; isoconversional methods ; kinetics ; model-free kinetics ; peak maximum evolution methods ; simulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In the case of a complex mechanism of two parallel independent reactions, peak maximum evolution methods and model-fitting methods give only a mean value of the kinetic parameters, while isoconversional methods are useful to describe the complexity of the mechanism. Isothermal and non-isothermal isoconversional methods can be used to elucidate the kinetics of the process. Nevertheless, isothermal isoconversional methods can be limited by restrictions on the temperature regions experimentally available because of duration times or detection limits.
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    Feasibility Study of Crude Oil Fields by Thermal Analysis Techniques (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 947-951 
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    ISSN: 1572-8943
    Keywords: combustion ; crude oil ; DSC ; TG/DTG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper investigates the minimum oil content necessary for self-sustained combustion, which is introduced as a criterion for the selection of suitable reservoirs for in-situ combustion processes. Differential scanning calorimetry was used to determine the heat values of oil-limestone mixtures. The minimum temperature required for the total consumption of the fuel was obtained by thermogravimetry (TG/DTG). The minimum amount of oil necessary to sustain combustion was calculated from these two parameters and compared with the oil content of the reservoir. Reservoirs with an oil content greater than or equal to this minimum value were considered feasible. It was seen that the fields examined are generally not suitable for in-situ combustion processes.
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    Kinetic Study of Thermal Decomposition of the DMIT Complex of Cobalt (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 805-810 
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    ISSN: 1572-8943
    Keywords: cobalt ; dmit ligand ; kinetics ; non-linear method ; Zsakó method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In this work, a cobalt complex with dmit (1,3-dithiol-2-thione-4,5-dithiolate) as ligand was prepared and its thermal stability was studied by thermogravimetric analysis and kinetics by means of the Zsakó method and a non-linear method. For both methods, numerical binomial and polynomial filters were used, where points in the central interval were utilized.
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    Isothermal Crystallisation of PCL Studied by Temperature Modulated Dynamic Mechanical and TMDSC Analysis (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1155-1161 
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    ISSN: 1572-8943
    Keywords: crystallisation ; DMA ; DSC ; PCL ; polymer ; temperature modulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Temperature modulated dynamic mechanical analysis (TMDMA) was performed in the same way as temperature modulated DSC (TMDSC) measurements. As in TMDSC TMDMA allows the investigation of reversible and non-reversible phenomena during crystallisation of polymers. The advantage of TMDMA compared to TMDSC is the high sensitivity for small and slow changes in crystallinity, e.g. during re-crystallisation. The combination of TMDMA and TMDSC yields new information about local processes at the surface of polymer crystallites. It is shown that during and after isothermal crystallisation the surface of the individual crystallites is in equilibrium with the surrounding melt.
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    DSC Analysis of the Induction Period in the Vulcanisation of Rubber Compounds (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1107-1113 
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    ISSN: 1572-8943
    Keywords: differential scanning calorimetry ; induction period ; kinetics ; vulcanisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Vulcanisation of rubber compounds was studied by DSC under isothermal and non-isothermal conditions. The parameters of an Arrhenius-like equation describing the temperature dependence of induction period have been obtained both from isothermal and non-isothermal measurements. A new method for obtaining the kinetic parameters from non-isothermal measurements, based on the dependence of onset temperature of vulcanisation peak on heating rate, is presented. Also, a procedure for the evaluation of temperature difference between the furnace and sample is proposed. It has been shown that the treatment of non-isothermal DSC measurements gives the kinetic parameters free of systematic errors. The new method can also be used for studying other reactions exhibiting the induction period.
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    The Influence of Annealing and Heavy Ion Irradiation of Multiple Melting and Crystallization in PBT Films (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1141-1146 
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    ISSN: 1572-8943
    Keywords: crystallization ; DSC ; heavy ion irradiation ; melting ; PBT films ; poly(butyleneterephthalate) films
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The influence of heavy ion-irradiation (Ar 5.5 MeV amu-1, 5·1011 ion cm-2) on the melting and crystallization of two PBT films subjected to different modes of thermal treatment was investigated. Differences were observed between the processes occurring in both initial films, due to differences in crystalline phase content. The course of melting and crystallization in heavy ion-irradiated films during first heating, cooling and second heating differs from that in the initial films. The density data and DSC results indicate a decreased crystalline phase content in the PBT films after irradiation.
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    Thermal Behaviour of Some Terpenoids (1999)
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    Journal of thermal analysis and calorimetry 56 (1999), S. 1353-1357 
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    ISSN: 1572-8943
    Keywords: DSC ; terpenoids ; TG ; thermal behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The terpenoids acetyl sitosterol, lupeol, acetyl diosgenin and stigmasterol were studied. Comparison of the thermogravimetric curves and the activation energies of the terpenoids suggested the following sequence of thermal stability: acetyl sitosterol 〈 acetyl diosgenin 〈 lupeol 〈 stigmasterol. The DSC curves allowed determination of the melting points and the degrees of purity. Comparison of the TG and DSC curves revealed the presence of phase transitions without mass loss that were attributed to rearrangements in the terpenoid molecules.
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    Lipid-similar Thermal Transition of Polyethylene Glycol Alkyl Ether Detergents (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 371-375 
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    ISSN: 1572-8943
    Keywords: C14E8 ; detergent ; DSC ; polyethylene glycol tetradecyl ether ; thermal transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A narrow, reversible endothermic main transition is found in the aqueous micellar phase of octaethylene glycol tetradecyl ether (C14E8) by DSC, characterized by a transition temperature of 41°C and a ΔH value of 0.5 kcal mol−1, which is not observed by light scattering. This transition is assigned to a cooperative conformational rearrangement of the assembled amphiphilic detergent molecules and not to a micelle aggregation process. It is suggested that the detergent’s polar head group is primarily involved in this rearrangement.
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    On the Oximine Complexes of Transition Metals: Part 110: Spectroscopic and DSC study on some [Fe(Diox·H)2L2] and [Fe(Diox)3(BOR)2] type chelates and clathrochelates (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 433-445 
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    ISSN: 1572-8943
    Keywords: DSC ; iron(II)-oxime complexes ; kinetic parameters ; Mössbauer spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A number of 15 [Fe(Diox#x00B7;H)2L2] type chelates and [Fe(Diox)3(BOR)2] clathrochelates (Diox#x00B7;H2 — dimethylglyoxime, glyoxime, propoxime, nyoxime, furyl-dioxime; L-pyridine, alkyl-pyridine derivatives, diethyl-phenyl-phosphine, diethyl-p-tolyl-phosphine) were obtained and characterized by means of far and middle FTIR and Mössbauer spectroscopic methods. Some structural problems were discussed on the basis of the optical data. The DSC measurements show the higher thermal stability of the clathrochelates without O—H⋯O intramolecular hydrogen bonds (with asymmetric octahedral structure), as compared to the [Fe(Diox#x00B7;H)2L2] trans, symmetric chelates containing O—H⋯O bonds. The kinetic parameters of the thermal decomposition of the complexes have been derived using the nomogram method.
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    Decoupled Molecular Dynamics of Glass-forming Liquids Confined in Nano-meter Pores (1999)
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    Journal of thermal analysis and calorimetry 57 (1999), S. 745-752 
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    ISSN: 1572-8943
    Keywords: confinement effects ; DSC ; dynamic light scattering ; finite-size effects ; glass transition ; o-terphenyl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Calorimetry is the method first used by Jackson and McKenna to study the effect of finite-size on the molecular dynamics of glass-formers confined in nano-meter scale pores. It was found that the glass transition is shifted to lower temperature as pore size decreases. Since then, other spectroscopic techniques have corroborated this finding and given more information on the molecular dynamics. These results are used to compare with the predictions of several theories of glass transition, and in particular the coupling model of the author.
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    URL: http://dx.doi.org/10.1023/A:1010169519847
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    Identification of Polyethylene by Differential Scanning Calorimetry: Application to forensic science (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 847-851 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; linear low-density polyethylene(LLDPE) ; low density polyethylene (LDPE) ; polymer blend ; thermal properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A forensic sample consisting of melt-recrystallized polymers that was recovered from the scene of a fire in a factory was identified by differential scanning calorimetry. The factory commonly used two kinds of film sheets, A and B, made by different manufacturers. It was necessary to decide whether the forensic sample related to material A or B. The forensic sample and reference samples of materials A and B were subjected to infrared spectroscopy and pyrolysis gas chromatograph mass spectrometry measurements, which revealed their polyethylene nature. The thermal behaviour of the samples was examined by differential scanning calorimetry (DSC) and they were found to be blends of two kinds of polyethylenes, low-density polyethylene and linear low-density polyethylene. The samples could be identified and distinguished from each other via the DSC measurements.
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    URL: http://dx.doi.org/10.1023/A:1010106612095
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    Estimation of the Critical Temperature of Thermal Explosion for the Highly Nitrated Nitrocellulose Using Non-isothermal DSC (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 369-373 
    Details
    ISSN: 1572-8943
    Keywords: critical temperature ; DSC ; HNNC ; non-isothermal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two methods for estimating the critical temperature (Tb) of thermal explosion for the highly nitrated nitrocellulose (HNNC) are derived from the Semenov's thermal explosion theory and two non-isothermal kinetic equations, dα/dt=Af(α)e−E/RT and dα/dt=Af(α)[1+E/(RT)(1–To/T)]e−E/RT, using reasonable hypotheses. We can easily obtain the values of the thermal decomposition activation energy (E), the onset temperature (Te) and the initial temperature (To) at which DSC curve deviates from the baseline of the non-isothermal DSC curve of HNNC, and then calculate the critical temperature (Tb) of thermal explosion by the two derived formulae. The results obtained with the two methods for HNNC are in agreement to each other.
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    URL: http://dx.doi.org/10.1023/A:1010155221958
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    Role of heat and gas transport processes in thermal analysis (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 197-211 
    Details
    ISSN: 1572-8943
    Keywords: gas/heat transport ; kinetics ; quasi static-methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Beim Verlauf von Feststoffreaktionen spielen Wärme- und Gastransport eine wesentliche Rolle. Eine Standardisierung der experimentellen Bedingungen wäre deshalb erforderlich, was jedoch bisher nur bezüglich der Erarbeitung von Simultantechniken gelang. Au\erdem sind diese beiden Transportprozesse dafür verantwortlich, da\ man ausgehend von nichtisothermen Kurven keine kinetischen Parameter berechnen kenn. Quasistatische Methoden scheinen geeignet zu sein, um den störenden Einflu\ dieser Transportprozesse zu eliminieren.
    Notes: Abstract In the course of solid phase reactions heat and gas transport processes play a dominant role. Therefore, it would be necessary to standardize the experimental conditions which succeeded only in part with the elaboration of the simultaneous techniques. Likewise the two transport processes are responsible for the fact that on the basis of non-isothermal curves one cannot calculate kinetic parameters of the reactions. The quasi static-methods seem to be suitable for the elimination of the pernicious effect of these transport processes.
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    URL: http://dx.doi.org/10.1007/BF02109119
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    Single run heat capacity measurements (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2257-2272 
    Details
    ISSN: 1572-8943
    Keywords: heat capacity ; data analysis ; differential scanning calorimeter ; DSC ; single run
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es werden die Grundzüge für die Datenanalyse von Wärmekapazitätsmessungen durch Doppelproben- DSC mit Einfachdurchgängen beschrieben: 1. Korrektion des Wärmeflusses durch Subtraktion des Beitrages des Probenbehälters, einschließlich der Korrektion nicht angeglichener Behältermassen. 2. Korrektion des Wärme flusses und der Temperatur mit einer nichtlinearen Temperaturkalibrierung, Korrektion von Temperaturverzögerung und Aufheizgeschwindigkeit. 3. Berechnung der Zellen-konstanten für beide Zellenpositionen und Ermittlung des Asymmetriefaktors zwischen den Zellenpositionen A und B. 4. Kalibrierung der Wärmekapazität und Berechnung mit Anstiegs- und Asymmetriekorrektion. 5. Berechnung der Wärmekapazität für Mehrfachdurchgänge. 6. Kurvenanpassung für die Wärmekapazität.
    Notes: Abstract An outline for the data analysis of single-run heat capacity measurments by dual sample DSC is presented with the following features: 1. Heat flow correction by subtracting the contribution due to the sample pan, including correction for mismatched pan masses. 2. Heat flow and temperature correction with a nonlinear temperature calibration, temperature lag correction, and heating rate correction. 3. Calculation of the cell constants for both cell positions and evaluation of the asymmetry factor between cell positions A and B. 4. Heat capacity calibration and calculation with slope and asymmetry correction. 5. Calculation of heat capacity for multiple runs. 6. Data curve fitting for heat capacity.
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    Derivatographic investigations of polycarbonates (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2211-2219 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; polycarbonates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Derivatographische, nichtisotherme Untersuchungen der Zersetzung von Polycarbonaten in Luft liefern nutzbringende Informationen über die charakteristischen Zersetzungstemperaturen und die scheinbaren Aktivierungsenergien der untersuchten Zersetzungsschritte. Dabei wurde folgende Reihenfolge der scheinbaren Aktivierungsenergie der Pyrolyseschritte beobachtet: PC-M PC-C PC-A. Wegen der Abschirmung der Esterketten durch ortho-Methylsubstituenten sind die Werte E für PC-M am höchsten.
    Notes: Abstract Derivatographic non-isothermal investigations of the decomposition of PC in air provide useful information on the characteristic decomposition temperatures and the apparent activation energies of the observed steps of decomposition. The following sequence of apparent activation energies of the pyrolysis step was obtained: PC-M〉PC-C〉PC-A. The values ofE for PC-M are the highest, due to shielding of the ester linkages by the ortho-methyl substituents.
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    URL: http://dx.doi.org/10.1007/BF01979635
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    Kinetics of isothermal decomposition of γ-irradiated and unirradiated Co(II) succinato complex (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2377-2383 
    Details
    ISSN: 1572-8943
    Keywords: Co(II) succinate complex ; isothermal decomposition ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Unter Anwendung von isothermen und dynamischen thermogravimetrischen Methoden wurde eine kinetische Untersuchung der Dehydratation und der Zersetzung von γ-bestrahltem und unbestrahltem Na2[Co(C4H4O4)2]·7H2O durchgeführt. Die thermische Dehydratation erfolgt in einem Schritt, bestimmt durch ein Random-Keimbildungsmodell (A3), während die Zersetzung der wasserfreien Salze durch ein phasengrenzenkontrolliertes Modell bestimmt wird (R3). Die bei drei Aufheizgeschwindigkeiten erhaltenen kinetischen Parameter stehen in guter Übereinstimmung; jedoch weichen die isotherm geschätzten kinetischen Parameter etwas von den dynamisch ermittelten ab. Bestrahlung mehrt sowohl die Dehydratations- als auch die Zersetzungsreaktionen, beläßt deren Mechanismus jedoch unverändert. Die Aktivierungsenergie sinkt mit zunehmender Strahlungsdosis.
    Notes: Abstract A kinetic study of the dehydration and decomposition of γ-irradiated and unirradiated Na2[Co(C4H4O4)2]·7H2O has been studied using isothermal and dynamic thermogravimetric methods. The thermal dehydration occurs in one step regulated by a random nucleation model (A3), while the decomposition of anhydrous salt is controlled by a phase boundary controlled model (R3). The kinetic parameters obtained at three heating rates are in good agreement; however, the values of the kinetic parameters estimated isothermally are slightly different from those estimated dynamically. Irradiation enhanced both the dehydration and the decomposition reactions but did not modify their mechanisms. The activation energy decreases as the irradiation dose increases.
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    URL: http://dx.doi.org/10.1007/BF02123991
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    Thermal and calorimetric studies of M(IO3)2·6H2O and M(IO3)2·6D2O forM 2+=Ca2+ and Sr2+ (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2491-2499 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; DTA ; M(IO3)2· 6H2O ; M(IO3)2·6D2O
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels DTA- und DSC-Methoden wurden Me(IO3)2·6H2O und Me(IO3)2·6D2O (mitMe 2+=Ca2+ und Sr2+) thermisch und kalorimetrisch untersucht. Es wird ein Überblick über das thermische Verhalten ordentlicher und deuterierter Hydrate gegeben, in dem auch die Unterschiede zwischen beiden diskutiert werden. Die Enthalpien der untersuchten Phasenumwandlungen wurden bestimmt. Aus den Daten für Hdeh wurde Hf von Ca(IO3)2·6H2O, Ca(IO3)2H2O(D2O) und Sr(IO3)2·6H2O(D2O) berechnet und Bemerkungen zum beobachteten Isotopeneffektes gemacht.
    Notes: Abstract Thermal and calorimetric studies were carried out on M(IO3)2·6H2O and M(IO3)2·6D2O forM 2+=Ca2+ and Sr2+, using DTA and DSC methods. The thermal behaviour of the ordinary and deuterated hydrates is outlined and the differences observed between them are discussed. The enthalpies of the phase transitions were determined. The ΔH f o for Ca(IO3)2·6H2O, Ca(IO3)2·6H2O(D2O) and Sr(IO3)2·6H2O(D2O) were calculated from the ΔH deh data and comments are made on the isotope effect observed.
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    On the fractional conversion α in the kinetic description of solid-state reactions (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2553-2557 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; solid-state reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract For the kinetic description of the solid-state reactions, the dependence of the apparent kinetic parameters on the sample mass and/or particle size is discussed mathematically in relation to some problems on the fractional conversion a. As for the reaction proceeding according to the contracting geometry model, the use of the specific rate constant, independent of the sample mass and particle size, is recommended to obtain the sample mass-independent Arrhenius parameters. It is also pointed out that the distribution of α within the assembly of sample particles disturbs the successful use of α in the kinetic description of the solid-state reactions.
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    URL: http://dx.doi.org/10.1007/BF01974632
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    Kinetic study of surface nucleated MgO-CaO-Al2O3-SiO2 glasses (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2639-2647 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; MgO-CaO-Al2O3-SiO2 glasses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Vorliegende Arbeit untersucht mittels thermoanalytischen Untersuchungen die Berechtigung von drei verschiedenen Methoden zur Ermittlung der Aktivierungsenergie der Kristallisation bei Gläsern mit Oberflächen-Kristallisationskeimen im System MgO-CaO-Al2O3-SiO2, wobei Anorthit- und Diopsidkristalle ausgeschieden werden. Die anhand der Kissinger-Gleichung erhaltenen Werte für die Aktivierungsenergie der Kristallisation sind vergleichbar mit denen, die von anderen Autoren für ähnliche Glassysteme erhalten wurden: 90–150 kcal/mol. Die Ergebnisse der kinetischen Analyse mittels der Einfach-Kristallisationspeak Methode sollten korrigiert werden, indem man die Dimensionalität des Kristallwachstums berücksichtigt.
    Notes: Abstract The paper investigated, by means of thermal analysis measurements, the validity of three different methods for the evaluation of the activation energy of crystallization for surface nucleated glasses belonging to the MgO-CaO-Al2O3-SiO2 system, separating anorthite and diopside crystals. The values obtained from Kissinger equation of the activation energy for crystallization are comparable with those obtained by other authors for similar glassy systems, 90 to 150 kcal/mol. The results of the kinetic analysis using single-crystallization-peak method should be corrected taking into account the dimensionality of crystal growth.
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    URL: http://dx.doi.org/10.1007/BF01979740
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    Thermal analysis and kinetic study of decomposition processes of some pesticides (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 2669-2682 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; pesticides ; thermodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels simultanen TG-DSC-Messungen und kinetischen Berechnungen bei der DTG-Technik wurde eine thermische Analyse einiger Pestizide durchgeführt. Mit dieser Methode wurde versucht, Verbindungen mit ähnlichen Strukturen anhand der Form und Anzahl von Peaks ihrer thermoanalytischen Kurven zu gruppieren und ihre Eigenschaften mittels thermodynamischen und kinetischen Mengen zu charakterisieren. Geringe Änderungen in der Struktur der Komponenten einer Klasse verursachen größere Veränderungen der thermodynamischen und kinetischen Größen, was in enger Übereinstimmung mit den beobachteten Unterschieden ihrer biologischen Aktivität steht.
    Notes: Abstract The thermal analysis of some pesticides using simultaneous TG-DSC measurements and kinetic calculations by the dynamic TG technique have been carried out. With this technique it was attempted to group compounds with similar structures according to the shape and number of peaks of their thermoanalytical curves and to characterize their features by means of thermodynamic and kinetic quantities. Small variations in the structure of the components of a class make larger variations in the thermodynamic and kinetic values being in close agreement with the observed differences in their biological behaviour.
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    (RS)-, (R)- and (S)-3-benzyl-3-ethyl 2-oxetanone polymerization with chiral and achiral initiators (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 303-311 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; polyester ; polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Polymerisation von 3-benzyl-3-ethyl 2-oxetanon führt zu drei Polymer Typen: PolyRS (überschuss des Enantiomers,EE=0), PolyR oder PolyS (REE 〉 SEE) und Polyracemate. Alle Polymere sind kristallin und die thermischen Eigenschaften (T g, SchmelzeT M und δH M) hängen wesentlich vonEE des Polymers ab. Die Fortpflanzung der Polymerisation ist nicht stereospeeifisch. Die Verwendung von Aufheitzen Abkühl Zyklen führt zu einer reinen kristallinen Form, die bei der höchsten Temperatur schmilzt. Das Polyracemat verhält sich wie ein reines Polymer, das bei niedrigeren Temperatur schmilzt; es racemisiert im Laufe einer verlängerten Erhitzung im Schemlzfluss.
    Notes: Abstract The polymerization of 3-benzyl-3-ethyl 2-oxetanones leads to three types of polymers: polyRS (enantiomer excess,ee=0), polyR or polyS (Ree 〉See) and polyracemate. All these polymers are crystalline and the thermal properties (T g, meltingT M and δH M) depend mainly on theee of the polymer. The propagation of the polymerization is not stereospecific. The use of heating-cooling cycles leads to a pure crystalline form melting at the highest temperature. The polyracemate has the behaviour of a pure polymer which melts at a lower temperature, a prolonged heating in the melt induces a strong racemization.
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    The limit of detection in differential scanning calorimetry (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 277-287 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; limit of detection ; polymorphic transitions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Anhand von sehr kleinen Signalen von spontanen polymorphen übergängen bei CsCl, K2Cr2O7 und Na2SO4 wird ein Verfahren zur Bestimmung der Nachweisgrenze von DSC-Geräten beschrieben. Es wird gezeigt, wie derartige Signale gut aufgelöst in DSC-Diagrammen von Pulverproben erhalten werden können. Um sie vom Rauschen der Basislinie zu unterscheiden, sollten sie eine Höhe von mindestens dem Doppelten der Basislinienbreite aufweisen. Für das angewendete Gerät beträgt die entsprechende geringste Wärmemenge, d.h. die Nachweisgrenze 0.1 mJ.
    Notes: Abstract A procedure is described to determine the limit of detection of DSC instruments by using tiny signals from spontaneous polymorphic transitions of CsCl, K2Cr2O7 and Na2SO4. It is shown how such signals can be found well-resolved in DSC diagrams of powder samples. To distinguish them from the baseline noise they should exhibit a height at least twice that of the baseline width. For the instrument employed the corresponding smallest amount of heat, i.e., the limit of detection, was found to be 0.1 mJ.
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    The thermal degradation kinetics of poly(chlorethylmethacrylates) (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 267-275 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; poly(chlorethyl methacrylates)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels TG wurde in Gegenwart und in Abwesenheit von Sauerstoff die Kinetik des thermischen Abbaues von Poly(2-mono, 2,2-di- und 2,2,2-trichlorethylmethacrylat) und des nichtchlorierten Poly(ethylmethacrylat) untersucht. Die mit der Flynn-Wall Methode bestimmte Gesamtenergie des thermischen Abbaues steigt mit wachsendem Chlorgehalt des Polymers, wenn der Abbau ohne Sauerstoff erfolgt. In Gegenwart von Sauerstoff wird dieser Trend genau umgekehrt. Mittels DTG konnten die zwei wichtigsten nichtoxidativen Thermolysereaktionen, Depolymerisierung und Vernetzung, als kompetitive Reaktionen nachgewiesen werden. Ganz allgemein wird die thermische Stabilität der untersuchten Polymere durch Sauerstoff herabgesetzt.
    Notes: Abstract The thermal degradation kinetics of poly(2-mono-, 2,2-di- and 2,2,2-trichlorethyl methacrylate) and of the non-chlorinated poly(ethyl methacrylate) were studied by TG in the absence and presence of oxygen. The overall thermal degradation energy, determined by the Flynn-Wall method, increases with increasing chlorine content of the polymer when the degradation is performed in the absence of oxygen, while the trend is reversed in the presence of oxygen. Competition between the two major non-oxidative thermolysis reactions, depolymerization and crosslinking, could be monitored by DTG. Generally, the thermal stability of the investigated polymers is reduced by oxygen.
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    High-speed versatile device for investigating thermal decomposition processes (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 391-396 
    Details
    ISSN: 1572-8943
    Keywords: intensive heating and cooling method and technique ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird eine neue Methode und ein neues Verfahren von thermoanalytischen Versuchen zur Untersuchung thermischer Zersetzungsprozesse sowie auch zur Bestimmung kinetischer und thermophysikalischer Eigenschaften von Feststoffen und Flüssigkeiten bei intensivem Erhitzen oder Abkühlen beschrieben.
    Notes: Abstract A new method and technique of TA-experiment are suggested for investigating thermal decomposition processes, as well as for determining kinetic and thermophysical characteristics of solid and liquid substances under conditions of intensive heating or cooling.
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    URL: http://dx.doi.org/10.1007/BF01915503
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    Thermomechanical analysis (TMA) correlated to differential scanning calorimetry (DSC) for ageing study of some metallic glasses (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 409-420 
    Details
    ISSN: 1572-8943
    Keywords: metallic glasses ; DSC ; TMA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Zur Charakterisierung des Alterns einiger metallischer Gläser wird in einer Vergleichsstudie der DSC-Methode und der thermomechanischen Analyse (TMA) die Spezifität letzterer hervorgehoben. Es wurden metallische Gläser untersucht, die entweder mittels chemischer Verfahren oder durch Schmelzverdüsen hergestellt wurden. Mittels DSC und TMA wurde festgestellt, da\ die Entspannung der metallischen Gläser stark von der Behandlungsweise abhängt, d.h. ob es sich um eine thermische oder mechanische Vorgeschichte handelt. Im Gegensatz dazu konnten bei der Kristallisation keine gro\en Unterschiede zwischen DSC und TMA gefunden werden. Anhand experimenteller Daten wurde versucht, das Verhalten derartiger Materialien unter den Betriebsbedingungen zu modellieren.
    Notes: Abstract To characterize the ageing of some metallic glasses, a correlated study of the differential scanning calorimetry method (DSC) and of the thermomechanical analysis (TMA) emphasizes the specificity of the latter. We analyzed metallic glasses which have been produced either by chemical methods or by melt spinning techniques. Using TMA and DSC, we have established that the relaxation of metallic glasses is strongly dependent on treatment applied: either thermal or mechanical history. Conversely, we do not observe large differences between DSC and TMA analysis for the crystallisation. From experimental data, we try to modelize the behaviour of this type of materials under operating conditions.
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    A kinetic study of water evolution from a molten hydrated salt (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 421-428 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; meso lithium potassium tartrate dihydrate ; molten hydrated salt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Meso-Lithiumkaliumtartrat-Dihydrat schmilzt noch vor der Dehydratation, eine kinetische Untersuchung dieser Reaktion wurde vollzogen. Dieses System ist interessant für die Abschätzung kinetischer Parameter von Prozessen mit gleichbleibender Geschwindigkeit ohne Gegenwart zugesetzter Lösungsmittel. Die Ergebnisse sind von Interesse bei überlegungen zu Mechanismen von Feststoffreaktionen oder Reaktionen im kondensierten Zustand, bei denen Schmelzen als Möglichkeit auftritt. Die Freisetzung der ersten 1.2 H2O aus den Einkristall-Dihydratreaktanden ist eine Reaktion nullter Ordnung, anschlie\end wird die Geschwindigkeit verlangsamt und unterliegt bis 1.6 H2O einem Ausdruck erster Ordnung. Der Vorgang weist eine hohe Aktivierungsenergie auf: 23010 kJ/mol (bei 350–380 K). Die Freisetzung des restlichen Wassers erfolgt in einer langsameren Reaktion erster Ordnung, man erhält das wasserfreie Salz. Die Dehydratation von zerkleinerten pulverisierten Reaktanden verlief anfangs relativ schneller, verlangsamt dann jedoch ganz und gar und unterliegt einer ersten Reaktionsordnung. Es wird geschlu\folgert, da\ die Dehydratation des Salzes durch die Freisetzungsgeschwindigkeit des Wassers an der Oberfläche kontrolliert wird, wobei das Wasser innerhalb der Reaktionsschmelze relativ beweglich ist.
    Notes: Abstract Meso lithium potassium tartrate dihydrate melted before dehydration and a kinetic study of this reaction has been completed. This system is of interest in establishing the kinetic characteristics of a homogeneous rate process in the absence of added solvent. Results are of interest in considering the mechanisms of solid or condensed state reactions where melting is a possibility. The evolution of the initial 1.2H2O from the single crystal dihydrate reactants was zero order, the rate then became deceleratory and the first order expression was obeyed to 1.6H2O. The activation energy of the process was high, 230±10 kJ mol−1 (350–380 K). Evolution of the remaining water occurred by a slower first-order process to give the anhydrous salt. The dehydration of crushed powder reactant was initially relatively more rapid but was deceleratory throughout, obeying the first order equation. It is concluded that salt dehydration is controlled by the rate of surface release of water that is comparatively mobile within the reactant melt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01915506
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    Significance of the kinetics of thermal decomposition of NaHCO3 evaluated by thermal analysis (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 429-435 
    Details
    ISSN: 1572-8943
    Keywords: compensation effect ; experimental conditions ; kinetics ; NaHCO3 ; thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels TG wurden sowohl bei konstanter als auch bei linear ansteigender Temperatur die Arrheniusschen Konstanten und das Kinetikgesetz der thermischen Zersetzung von Natriumhydrogencarbonat bestimmt. Dabei wurde der Einflu\ der Probengrö\e (0.5–10mg) und der Partikelgrö\e auf das Geschwindigkeitsverhalten untersucht. Mit Proben kleiner als etwa 5 mg ist der Einflu\ der Aufheizgeschwindigkeit nicht so gro\, wie bei grö\eren Proben. Die ermittelten Arrheniusschen Parameter und das ermittelte Kinetikgesetz, bestimmt mittels der Methode von Ozawa, stehen in ausgezeichneter übereinstimmung mit den isotherm ermittelten Resultaten. Die Aktivierungsenergie E bei einer Probe mit einer Masse von etwa 1 mg war nahezu konstant, unabhängig vom Reaktionsgrad. Jede änderung des Arrheniusschen Parameters infolge von veränderten Versuchsbedingungen wurde in Verbindung mit dem kinetischen Kompensationseffekt diskutiert.
    Notes: Abstract The Arrhenius parameters and kinetic obedience were determined by TG at constant temperatures as well as at linearly increasing temperatures for the thermal decomposition of sodium hydrogencarbonate. Effects of the sample size (0.5–10 mg) and the particle size on the rate behavior were examined. With such a sample size smaller than ca. 5 mg, an effect of the heating rate was not so critical as is the case with the larger sample size. The Arrhenius parameters and kinetic obedience determined by use of the Ozawa method were in excellent agreement with those determined isothermally. The activation energyE determined with ca. 1 mg of sample was nearly constant independently of the fractional reactiona. Any change in the Arrhenius parameters with different experimental conditions was dicussed in connection with the kinetic compensation effect.
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    URL: http://dx.doi.org/10.1007/BF01915507
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  • 95
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    New reference materials for the calibration (temperature and energy) of differential thermal analysers and scanning calorimeters (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 855-863 
    Details
    ISSN: 1572-8943
    Keywords: calibration materials ; DSC ; DTA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Als neue Referenzsubstanzen für Temperatur- und Energiekalibrierung von DTA- und DSC-Geräten wurden im Temperaturbereich 300–600 K einige organische Verbindungen, wie z.B. Phenanthren, Benzanilid, Anissäure, Triphenylen, 2-Chloranthrachinon, Hexachlorbenzol, Karbazol, 4-Jodbenzoesäure, Perylen und Anthrachinon untersucht.
    Notes: Abstract Several organic compounds like phenanthrene, benzanilide, anisic acid, triphenylene, 2-chloroanthraquinone, hexachlorobenzene, carbazole, 4-iodobenzoic acid, perylene, anthraquinone, as new reference materials for temperature and energy calibration of DTA and DSC apparatuses were studied in the range 300—600 K.
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    URL: http://dx.doi.org/10.1007/BF01979417
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  • 96
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    Factors affecting the experimentally resolved shapes of TG curves (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 575-582 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; shapes of TG curves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Unter theoretischen Aspekten bezüglich derjenigen Faktoren, die die experimentelle Auflösung thermogravimetrischer Kurven beeinflussen, wird ein möglicher Weg zur Steigerung der Genauigkeit thermogravimetrischer Untersuchungen diskutiert.
    Notes: Abstract From a theoretical consideration concerning the factors affecting the experimentally resolved shapes of thermogravimetric curves, the possible way to increase the accuracy of the thermogravimetric measurements were discussed.
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    URL: http://dx.doi.org/10.1007/BF01979384
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  • 97
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    Modelling of diffusion-controlled solid-solid reactions (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 935-941 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; solid-solid reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird ein Modell zur Beschreibung des einleitenden Schrittes von diffusionskontrollierten Feststoffreaktionen beschrieben. Die erhaltene kinetische Gleichung wurde zur Bestimmung der Aktivierungsenergie der Reaktion LiCl(s) + NaF(s)=LiF(s) + NaCl(s) aus DTA-Daten angewendet.
    Notes: Abstract A model describing the initial step of diffusion-controlled solid-solid reactions is presented. The kinetic equation obtained was used to evaluate the activation energy of the reaction LiCl(s)+NaF(s)=LiF(s)+NaCl(s) from DTA data.
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    URL: http://dx.doi.org/10.1007/BF01979426
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    A comparison of some integral methods (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 929-933 
    Details
    ISSN: 1572-8943
    Keywords: integral methods ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Integrationsmethoden zur Berechnung kinetischer Parameter von heterogenen Reaktionen unter nicht isothermen Bedingungen werden im allgemeinen nach der Methode der kleinsten Quadrate erarbeitet und der ermittelte Korrelationskoeffizient dient als ein Kriterium für die Auswahl der besten Integrationsmethode. Mittels drei verschiedenen Integrationsmethoden wurde eine Analyse verschiedener experimenteller Daten durchgeführt. Die Ergebnisse zeigen, daß dieses Kriterium allein nicht ausreicht, um ausreichende Informationen über die kinetischen Parameter zu liefern. Es scheint deshalb, daß die Verwendung der einen oder anderen Integrationsmethode einfach eine Wahl des Anwenders darstellt.
    Notes: Abstract The integral methods proposed to compute the kinetic parameters of heterogeneous reactions under non-isothermal conditions are usually worked by the help of the least squares method and the obtained correlation coefficient is taken as a criterion to choose the best integral method. An analysis of several experimental data by mean of three different integral methods was performed by us and the results pointed out that this criterion, by itself, is not enough to provide reliable information on the kinetic parameters. It appears, thus, that the use of an integral method or another is a simple matter of researcher's choice.
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    URL: http://dx.doi.org/10.1007/BF01979425
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  • 99
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    The thermal degradation kinetics of poly(di-n-alkylitaconates) (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 953-959 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; poly(di-n-alkyl itaconates) ; thermal stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels nichtisothermer und auch isothermer TG wurde die nichtoxidative thermische Zersetzungskinetik von Poly(di-n-alkylitakonaten) untersucht, dabei bewegt sich die Länge der Alkylkette von Methyl bisn-Oktyl. Die Aktivierungsenergie der thermischen Zersetzung und die charakteristischen Masseverlusttemperaturen nehmen mit steigender Substituentlänge ab. Aussehen der DTG-Kurven hängt von der Größe der Alkylkette ab. Die verschiedenen DTG-Maxima wurden verschiedenen Initiierungs schritten der Depolymerisierung zugeschrieben. Man fand, daß im Intervall Mw zwischen 104 und 107 g·mol die thermische Stabilität der Poly(di-n-hexylitakonate) unabhängig von der anfänglichen molaren Masse der Probe ist.
    Notes: Abstract The non-oxidative thermal degradation kinetics of poly(di-n-alkyl itaconates), ranging from the methyl to then-octyl derivatives, were studied by non-isothermal and isothermal TG. The thermal degradation activation energy and characteristic mass loss temperatures were found to decrease with increasing substituent size. The shapes of the DTG curves were dependent on the size of the alkyl substituent. The different DTG maxima were ascribed to various modes of initiation of depolymerisation. The thermal stability of poly(di-n-hexyl itaconate) was found to be independent of the initial molar mass of the sample in the range ofM w from 104 to 107 g/mol.
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    URL: http://dx.doi.org/10.1007/BF01979428
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  • 100
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    Rapid thermal analysis of processes of thermal decomposition of mineral salts (1992)
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 981-988 
    Details
    ISSN: 1572-8943
    Keywords: kinetics ; mineral salts ; rapid TA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Für thermische Zersetzung und Synthese von Mineralsalzen wurden die kinetischen Kurven unter den Bedingungen schnellen Aufheizens in Annäherung der Aufheizbedingungen in einem Niedertemperatur-Plasmastrom ermittelt. Die kinetischen Eigenschaften wurden zur Berechnung der Umwandlungen bei einem chemischen Plasmareaktor verwendet.
    Notes: Abstract Kinetic curves of thermal decomposition and synthesis of mineral salts are obtained in the conditions of rapid heating approaching the heating conditions in a low-temperature plasma flow. The kinetic characteristics are used in calculations of transformations in the path of a chemical plasma reactor.
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    URL: http://dx.doi.org/10.1007/BF01979431
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