This research was aimed
to investigate the role of clay on the combustion and kinetic behavior of
crude oils in limestone matrix. For this purpose, simultaneous TG (thermogravimetry)
and DTA (differential thermal analysis) experiments were performed at three
different heating rates as 10–15 and 20C min–1,
respectively. A uniform trend of decreasing activation energies was observed
with the addition of clay. It was concluded that clays surface area affects
the values of Arrhenius constant, while it is the catalytic properties of
clay, which lower the activation energies of all the reactions, involved in
the combustion process.
Authors:M. Kök, G. Pokol, C. Keskin, J. Madarász, and S. Bagci
In this research thermal analysis and kinetics of ten lignite's and two oil shale samples of different origin were performed
using a TA 2960 thermal analysis system with thermogravimetry (TG/DTG) and differential al analysis (DTA) modules. Experiments
were performed with a sample size of ~10 mg, heating rate of 10C min-1. Flow rate was kept constant (10 L h-1) in the temperature range of 20-900C. Mainly three different reaction regions were observed in most of the samples studied.
The first region was due to the evaporation of moisture in the sample. The second region was due to the release of volatile
matter and burning of carbon and called as primary reaction region. Third region was due to the decomposition of mineral matter
in samples studied. In kinetic calculations, oxidation of lignite and oil shale is described by first-order kinetics. Depending
on the characteristics of the samples, the activation energy values are varied and the results are discussed.
, chemistry, physics, health care, and materials science. In addition to meeting the next generation of technical challenges, thermal analysts face the challenge of attracting and retaining the next generation of the thermalanalysis (TA) community
Authors:N. Sbirrazzuoli, D. Brunel, and L. Elégant
Feedforward neural networks have been used for kinetic parameters determination and signal filtering in differential scanning calorimetry. The proper learning function was chosen and the network topology was optimized, using an empiric procedure. The learning process was achieved using simulated thermoanalytical curves. The resilient-propagation algorithm have led to the best minimization of the error computed over all the patterns. Relative errors on the thermodynamic and kinetic parameters were evaluated and compared to those obtained with the usual thermal analysis methods (single scan methods). The errors are much lower, especially in presence of noisy signals. Then, our program was adapted to simulate thermal effects with known thermodynamic and kinetic parameters, generated electrically, using a PC computer and an electronic interface on the serial port. These thermal effects have been generated by using an inconel thread.
Beypazari lignite was investigated by differential scanning calorimetry (DSC), thermogravimetry (TG), high pressure thermogravimetry
(HPTG) and combustion cell experiments. All the experiments were conducted at non-isothermal heating conditions with a heating
rate of 10°C min−1, in the temperature range of 20–700°C. DSC-TG data were analysed using an Arrhenius-type reaction model assuming a first-order
reaction. For the HPTG data the Coats and Redfern equation was used for kinetic analysis. In the combustion cell experiments
the Fassihi and Brigham approach was used in order to calculate kinetic data. Finally a comparison is made between the kinetic
Authors:Petra Šulcová, Jan Večeřa, and Pavel Bystrzycki
purity of the synthesized samples were characterized by powder X-ray diffraction using conventional powder techniques in diffractometer (D8 Bruker, GB) with Cu K λ radiation.
Thermal gravimetric analysis/differential thermalanalysis was
The purpose of this study was to conduct a thermal analysis of the hydrolysis and degradation behavior of biodegradable polymers
and bio-composites at 50°C and 90% relative humidity (RH). With increasing hydrolysis time, the thermal stability and degradation
temperature of polybutylene succinate (PBS) slightly decreased. The glass transition temperature (Tg) and melting temperature (Tm) of PBS and the anti-hydrolysis agent treated PBS did not vary significantly with increasing hydrolysis time, whereas those
of the trimethylolpropane triacrylate (TMPTA)-treated PBS slightly increased. With increasing hydrolysis time, the storage
modulus (E’) values of the bio-composites decreased, whereas those of the TMPTA treated bio-composites slightly increased. Also, the
tan values of the anti-hydrolysis agent and TMPTA treated PBS-BF bio-composites were slightly lower than those of the non-treated
bio-composites, due to the reduction in their degree of hydrolysis. The tanδmax peak temperature (Tg) of the anti-hydrolysis agent treated bio-composites was not significantly changed, whereas that of the TMPTA treated bio-composites
Authors:Alexander Kozlov, Denis Svishchev, Igor Donskoy, and Alexandre V. Keiko
characteristics, including those directly measured.
An important role in development of new gasification technologies and improvement of known ones belongs to the physicochemical methods of research. Among them thermalanalysis is typical for studies on
Authors:L. M. Federico, S. E. Chidiac, and L. Raki
. Carbonation of the samples in the form of CaCO 3 was generally below 2.0% for low alkali mixtures and below 3.3% for high alkali mixtures. Simultaneous differential thermalanalysis (DTA) was performed on crushed samples using a TA Q600 in nitrogen gas at 100
This review traces the development of thermal analysis over the last 40 years as it was experienced and contributed to by the author. The article touches upon the beginning of calorimetry and thermal analysis of polymers, the development of differential scanning calorimetry (DSC), single run DSC and other special instrumentations, up to the recent addition of modulation to calorimetry. Many new words and phrases have been introduced to the field by the author and his students, leaving a trail of the varied interests one can have over 40 years. It began with “cold crystallization” and most recently the term “oriented, intermediate phase” was coined, creating in-between: “extended chain crystals,” the “irreversible thermodynamics of melting of polymer crystals,” “dynamic differential thermal analysis” (DDTA), “the rule of constant increase ofCp per mobile bead within a molecule at the glass transition temperature,” “superheating of polymer crystals,” “melting kinetics,” “crystallization during polymerization,” the “chain-folding principle, “molecular nucleation,” “rigid amorphous phase,” a “system of classifying molecules,” “macroconformations,” “amorphous defects,” “rules for the entropy of fusion based on molecular shape and flexibility,” “single-molecule single-crystals,” “a system of classifying phases and mesophases,” and “condis phase.”