Maximum Peak Temperature Research Articles

Improved thermoluminescence and kinetic parameters of new strontium/copper co-doped lithium borate glass system

We report the modified thermoluminescence (TL) response of a new melt-quench synthesized strontium (Sr) doped lithium borate (LBSr) glass system co-doped with copper (Cu). Both Sr (0.5–2.5 mol%) and Cu (0.005–0.1 mol%) concentrations are varied to determine the optimum TL properties by exposing them to 6 and 10 MeV electrons irradiations. A single broad TL peak with the maximum peak temperature around 180–220 °C is evidenced. Glass sample with 2 mol% of Sr and 0.01 mol% of Cu content revealed the optimum TL response in addition to superior linearity in the dose range of 0.5–4 Gy. The dose dependent minimum detectable dose, fading, and reproducibility are determined. Samples displayed higher sensitivity to 10 MeV electron irradiations than to 6 MeV. Furthermore, this new composition showed easy annealing, excellent reproducibility, minimal fading and obeyed second order kinetics. These attractive features make the achieved glass system prospective for radiation dosimeter fabrication.

Investigation of Physico Chemical Properties and Characterization of New Natural Cellulosic Fibers from the Bark of Ficus Racemosa

ABSTRACT The objective of this examination is to characterize the fibers from the bark of Ficus racemosa fibers (FRF). FRF is composed of cellulose (72.36 wt. %), hemicellulose (11.21wt. %), lignin (10.45 wt. %), and has a density of 895 Kg/m3. The Differential thermogravimetry (DTG) shows that the maximum degradation peak temperature was attained at 310.56°C. The presence of a chemical group in the fibers was revealed through Fourier transform (FT-IR) analysis. The crystalline structure was characterized by X-ray diffraction (XRD). For surface morphology, Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) were used. The obtained results indicated that FRFs are suitable fibers for polymer composite as reinforcement.

Suitable temperature assignment for liquidus line in SLE investigation by DSC

The solid–liquid equilibria (SLE) of two binary mixtures of organic stabilizers for energetic materials, viz. N-(2-methoxyethyl)-p-nitroaniline + 2-nitrodiphenylamine (S1) and N-(2-methoxyethyl)-p-nitroaniline + 1,3-diethyl-1,3-diphenylurea (S2), have been determined using differential scanning calorimetry at three heating rates β (0.5, 1, and 2 K min−1). The liquidus line has been predicted using four characteristic points of the mixture melting curve as follows: the maximum peak temperature (Ttop), the temperature proposed by the German Society of Thermal Analysis (TGEFTA), the inflection point temperature (Tinf), and the endset temperature (Tendset) obtained at β= 1 K min−1 and by extrapolating the three heat flow curves at β= 0 K min−1. The melting temperatures of pure compounds and the eutectics have been identified from the onset temperature obtained at β= 0 K min−1. The quality of the prediction has been evaluated by the computation of the global quality factor from SLE consistency tests and by the estimation of the uncertainty associated with each investigated temperature. It was found that the inflection point displays the highest quality factors and the lowest uncertainties. Moreover, and for practical purposes, the inflection temperature obtained at β= 1 K min−1 generated more consistent data and lowest uncertainties than the other temperatures obtained even at β= 0 K min−1.

SOL-GEL α-Al2O3 samples: Analysis of the TL kinetics

The analysis of the thermoluminiscence (TL) kinetics parameters of SOL-GEL α-Al2O3 with several different concentrations of impurities prepared through the solgel process is reported. A TL glow curve measured at 0.2 K/s after beta irradiation to 0.5 Gy revealed one peak at approximately 447 K. TL spectra were acquired and showed luminescent emission bands around 420 nm and 750 nm. The activation energies, the frequency factors, and the kinetic order involved in the TL emission were evaluated using the maximum peak temperature response, the peak shape of the TL glow curve, the TL glow curve area, and the glow curve fitting methods. The order of kinetics of the peak was evaluated as first order using TM dependence on the radiation dose. The (TM–Tstop) technique was used for determining the number of peaks in the glow curve. The activation energies obtained are in agreement with all the applied methods. The activation energy calculated by various methods varied from 0.885 ± 0.008 eV to 1.05 ± 0.10 eV. The frequency factor determined by all methods was of the order of 109 s−1. The dosimetric peak is affected by thermal quenching. The following thermal quenching parameters were estimated: the activation energy of the thermal quenching W = 1.05 ± 0.15 eV and the constant C = 8.27 × 1010 s−1. The trapping parameters of SOL-GEL α-Al2O3 detectors are reported in the present work for the first time.

Effect of heating rate on thermoluminescence characteristics of Y2O3 nanoparticles

The present paper reports the results of heating rate dependencies of thermoluminescence (TL) peaks observed for Y2O3 nanoparticles in the below room temperature region. TL glow curve presented six peaks around 62.5, 91.3, 114.5, 162.7, 196.0 and 214.9 K for heating rate of 0.4 K/s. The increase of heating rate resulted in increase in peak maximum temperature and decrease in peak maximum intensity as expected according to theoretical information. Peak maximum temperature-heating rate dependencies of observed peaks were analysed according to exponential dependency relation. Curve fit and initial rise methods were applied on thermally cleaned individual peaks and activation energies of associated trap centers, frequency factors and order of kinetics were obtained from the analyses. Activation energy values of the revealed trapping centers found from both methods were in good agreement with each other. Moreover, lattice parameters, crystalline size and micro-strain of nanoparticles were investigated by means of x-ray diffraction measurements.

Co-pyrolysis of binary and ternary mixtures of microalgae, wood and waste tires through TGA

Degradation behavior and kinetics of microalgae chlorella vulgaris, wood, scrap tire and binary and ternary mixtures were investigated by using thermogravimetry analysis method. Experiments were carried out at different heating rates of 10−20and40°C/min from ambient temperature to 600 °C. The results showed that decomposition of microalgae, wood and tire take place in three stages and the second stage is the main thermal decomposition step. Besides, heating rate enhancements shift the maximum peak temperature of microalgae, wood and scrap tire from 300 °C, 350 °C and 380 °C to 340 °C, 390 °C and 420 °C, respectively. In the case of the ternary mixture, the maximum peak temperature of the mixture was approximately equal to the maximum peak temperature of the tire. The interaction between materials was studied and the results showed that the interaction is inhibitive rather than synergistic. The results of kinetic investigation showed that the tire and the wood have the highest (273.64 kJ/mol) and the lowest (120.96 kJ/mol) activation energy, respectively. The presence of wood and microalgae increased the total weight loss of binary mixture of microalgae-tire and wood-tire, while tire presence did not improve the degradation of microalgae-wood mixture.

Effects of Excavation Damaged Zone on Thermal Analysis of Multi-layer Geological Repository

As the present single-layer repository concept requires too large an area for the site of the repository, a multi-layer repository concept has been suggested to improve the disposal density. The effects of the excavation damaged zone around the multi-layer repository constructed in the deep host rock on the temperature distribution in the repository were analyzed. For the thermal analysis of the multi-layer repository, the hydrothermal model was used to consider the resaturation process occurring in the buffer, backfill and rock. The existence of an excavation damaged zone has a significant effect on the temperature distribution in the repository, and the maximum peak temperatures of double-layer and triple-layer repositories can rise to 7℃ and 12℃, respectively depending on the size of the excavation damaged zone and the degree of decrease of the thermal conductivity. The dominant factor affecting the peak temperature in the multi-layer repository is the decrease of thermal conductivity in the excavation damaged zone, and the excavation damaged zone formed around the deposition hole has more significant effects on the peak temperature than does the excavation damaged zone formed around the disposal tunnel.

Traps distribution in sol-gel synthesized ZnO nanoparticles

The distribution of shallow traps within the sol-gel synthesized ZnO nanoparticles was investigated using thermoluminescence (TL) experiments in the 10–300 K temperature range. TL measurements presented two overlapped peaks around 110 and 155 K. The experimental technique based on radiating the nanoparticles at different temperatures (Texc.) between 60 and 125 K was carried out to understand the trap distribution characteristics of peaks. It was observed that peak maximum temperature shifted to higher values and activation energy (Et) increased as irradiating temperature was increased. The Et vs. Texc. presented that ZnO nanoparticles have quasi-continuously distributed traps possessing activation energies increasing from 80 to 171 meV.

Low temperature thermoluminescence of Gd2O3 nanoparticles using various heating rate and Tmax − Texc. methods

Abstract Thermoluminescence (TL) measurements for Gd2O3 nanoparticles were carried out for various heating rates between 0.3 and 0.8 K/s at low temperatures (10–280 K). TL spectrum exhibited two observable and one faint peaks in the temperature region of 10–100 K, and four peaks in the temperature region of 160–280 K. Heating rate analysis was achieved to understand the behaviors of trap levels. It was seen that the peak maximum temperatures and TL intensities of all peaks increase with increasing heating rate. This behavior was ascribed to anomalous heating rate effect. Tmax − Texc. analysis was accomplished for TL peaks at relatively higher temperature region to reveal the related traps depths. Tmax − Texc. plot presented a staircase structure indicating that the TL glow curve is composed of well separated glow peaks. Mean activation energies of trapping centers corresponding to these separated peaks were found as 0.43, 0.50, 0.58 and 0.80 eV.

Effect of particle size on thermal decomposition and devolatilization kinetics of melon seed shell

Thermogravimetric analysis (TGA) and devolatilization kinetics of melon seed shell (MSS) at different particle sizes (150 µm and 500 µm) and at different heating rates (10, 15, 20, and 25 °C/min) were investigated with the aid of TGA. The results of the TGA analysis show that the TGA curves corresponding to the first and third stages for 150 µm particle sizes exhibited some bumps that developed at the first and third stages of pyrolysis. It was also observed that at constant heating rate, the maximum peak temperature increases as the particle sizes increase from 150 to 500 µm, whereas 500 µm particle sizes exhibited higher peak temperatures compared to 150 µm particle sizes. The resulting TGA data were applied to the Kissinger (K), Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) methods and kinetic parameters (activation energy, E and frequency factor, A) were determined. The E and A obtained using K method were 74.27 kJ mol−1 and 3.84 × 105 min−1 for 150 µm particle size, whereas for 500 µm particle size were 97.12 kJ mol−1 and 3.74 × 107 min−1, respectively. However, the average E and A obtained using KAS and FWO methods were 82.35 kJ mol−1, 1.29 × 107 min−1, and 88.50 kJ mol−1, 1.32 × 107 min−1 for 150 µm particle sizes. While for 500 µm particle sizes, the E and A were 108.46 kJ mol−1, 3.14 × 109 min−1, and 113.05 kJ mol−1, 7.56 × 109 min−1, respectively. It was observed that E and A calculated from FWO and KAS methods were very close and higher than that obtained by K method. It was observed that the minimum heat required for the cracking of MSS particles into products is reached later at higher peak temperatures since the heat transfer is less effective as they are at lower peak temperatures.

Влияние скорости тепловой акклимации на жирнокислотный состав и фазовые переходы гликолипидов Saccharina japonica (J.E. Areschoug)

Saccharina japonica is a valuable commercial species and the most common object of mariculture. Temperature is a powerful factor determining the growth and development of macroalgae. Rational mariculture and an understanding of the dynamics of marine ecosystems require the study of the physicochemical basis of temperature adaptation. The key mechanism of this process is the redistribution of the fatty acid (FA) composition of polar lipids, maintaining the optimal liquid-crystalline state of the biomembrane lipid matrix. In the conditions of increasing ambient temperature variability, the rate of changes aimed at the thermal adaptation of ectothermic organisms, which include plants, becomes particularly important. However, to date, the effect of the temperature acclimation rate on ectothermic organisms has been little studied. The present paper aims to study the ability of S. japonica to adapt the physicochemical properties of the main polar lipids to elevated ambient temperature at different rates of seawater heating. Algae were collected in the Sea of Japan in winter at a water temperature of 4 °C and warmed to a summer temperature of 20 °C at rates of 16 °C/d (rapid acclimation) and 2 °C/d (slow acclimation). We isolated glycolipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and sulfoquinovosyldiacylglycerol (SQDG) from acclimated algae as well as their thalli, collected in winter and summer, and studied their FA composition, the composition of molecular species and thermal transitions from crystalline state to liquid crystalline state, which is optimal for functioning of biomembranes, by GLC, HPLC-MS and differential scanning calorimetry (DSC), respectively. Statistical significance was analyzed using Student’s t-test (p ≤ 0.05). The results of this study showed that rapid thermal acclimation caused an increase in the unsaturation index (UI) and the ratio of unsaturated/saturated FA of the main lipid of thylakoid membranes MGDG (See Table 1), in contrast to both acclimatization and acclimation changes in the FA composition of the remaining glycolipids DGDG and SQDG when a season changes from winter to summer (See Tables 2-3). The opposite character of changes in the unsaturation of the FA composition of MGDG compared with DGDG and SQDG was also preserved during slow thermal acclimation. Slow warming only strengthened this feature in MGDG, contributed to increasing the unsaturation of FA composition of DGDG as opposed to the effect of rapid acclimation or weakened its effect in SQDG. The ratio of n-3/n-6 polyunsaturated fatty acids (PUFAs), the decrease of which, that is, increase in the share of n-6 PUFAs in polar lipids of marine macrophytes during thermal acclimatization is important both for regulating the viscosity of membrane lipids, and for strengthening mediators derived from PUFAs in the physiologically active season. However, during thermal acclimation, the n-3/n-6 ratio of PUFAs changed a little in MGDG and SQDG of S. japonica regardless of the acclimation rate. Only in DGDG, the n-3/n-6 ratio of PUFAs decreased in accordance with the seasonal trend, especially at rapid acclimation. These changes in the FA composition of glycolipids were accompanied by equally ambiguous changes in their thermotropic behavior. Thermal acclimation caused the phase separation of MGDG, which was characterized by splitting of the peak of crystal – liquid crystal thermal transition of the glycolipid into the low and high temperature peaks, while the seasonal effect contributed to a decrease in the peak maximum temperature (Tmax) to the low temperature region by 20°C (See Fig. 1a). Phase separation of MGDG was accompanied by an increase in the percentage of molecular PUFA/PUFA forms, as well as monounsaturated FA (MUFA)/PUFA, and a decrease in saturated FA (SFA)/ PUFA (See Table 4). However, the warming up of sea water at a rate of 16°C/d and 2°C/d was not enough to bring the profile of the thermogram acclimatization and acclimation closer to that of the summer sample. Similar acclimation changes, which had a character of the emerging trend of fitting the profile of thermograms, were observed in the DGDG and SQDG calorimetric transitions (See Fig. 1b, c), which were based not so much on the FA composition as a whole but on the composition of their molecular species/forms (See Tables 5-6). Consequently, an increase in seawater temperature from 4 °C to 20 °C at rates of 16 °C/d or 2 °C/d showed an ambiguous, stressful nature of the FA composition and calorimetric transitions of glycolipids from S. japonica during thermal acclimation. The low efficiency of molecular mechanisms underlying maintenance of the liquid crystalline state of the main polar lipids of S. japonica that is optimal for functioning of the membranes is probably due to cold-loving nature and absence of sharp temperature fluctuations in the natural habitats of this species of marine macroalgae.

Numerical analysis of the effect of gap-filling options on the maximum peak temperature of a buffer in an HLW repository

The gaps around the buffer in a high-level waste (HLW) repository have a significant influence on the temperature of the buffer and its long-term performance. This study carried out numerical simulations to analyze the effect of void and filling options on the peak temperature in the buffer. The presence of void inner and outer gaps around the buffer greatly raised the peak temperature of the buffer. However, this high peak temperature was lowered by fillings (bentonite pellets) into the outer gap, and it also decreased with the increase in the dry density and degree of saturation of fillings and the decrease in outer gap spacing. On the other hand, for the inner gap, it was advantageous to leave it empty in lowering the peak temperature of the buffer. The peak temperature compared to the void inner gap, when also considering the effect of radiation, showed only a very minor reduction when the average temperature in the gap, gap spacing, and the emissivity of the copper canister surface decreased. Based on the results of the above numerical simulations, this study also proposed a buffer-gap system that minimizes the peak temperature of the buffer.

Compatibility and thermokinetics studies of octahydro- 1,3,5,7-tetranitro-1,3,5,7-tetrazocine with polyether-based polyurethane containing different curatives

ABSTRACTA compatibility of energetic compound with polymeric matrices is of prime importance in the pre-formulation stage for developing of new energetic composite formulations. In the present work, the compatibility of octahydro-l,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) with polyether (PET) polyol (trade name SP-755)-based polyurethanes (PUs) containing different curatives such as 4,4ʹmethylene diphenyl diisocyanate (MDI), isophorone diisocyanate (IPDI), 2,2,4-trimethylhexamethylene diisocyanate (TMDI), and toluene diisocyanate (TDI) has been studied by using a differential scanning calorimetry method. The PET-based PUs were prepared by polymerization between PET polyol and different curatives, then these PUs were further mixed with HMX to study the compatibility and kinetic parameters. Results show that the compatibility and thermal stability are significantly influenced by the different curatives, and suggested thermals stability by thermal data follow the order for a mixture of HMX/SP-755/MDI > HMX/SP-755/TDI > HMX/SP-755/IPDI > HMX/SP-755/TMDI. The thermal degradation kinetics has also been investigated through non-isothermal conditions using the Kissinger and the isoconversional ASTM E689 kinetic methods. The finding shows that there was a significant variation in the apparent activation energy for a mixture of HMX/SP-755/MDI, HMX/SP-755/IPDI, HMX/SP-755/TMDI, and HMX/SP-755/TDI, which were 365.8, 257.7, 134.9, and 241.1 kJ mol−1, respectively. The apparent activation energies obtained from the Kissinger method at maximum peak temperature are in reasonable agreement and consistent with isoconversional ASTM E689 kinetic method.

Magnetic and magnetocaloric properties of the Co2-xMnxB system by experiment and density functional theory

The Co2B system shows a significant magnetovolume effect around its Curie temperature which makes it potentially attractive for magnetocaloric applications or thermomagnetic power generation, as a large coupling between the lattice and spin degrees of freedom is expected. We report on the synthesis of a series of Co2-xMnxB alloys and the investigation of their properties. The structural analysis indicates a single phase behavior up to x = 0.8 with no structural symmetry changes throughout the series. Measurements of both, macroscopic and local magnetic properties, reveal an anomalous behavior of the spontaneous magnetization, Curie temperature, and element-specific magnetic moments as a function of manganese concentration. The elemental contributions to the magnetization are analyzed using nuclear magnetic resonance (NMR) studies. Density functional theory (DFT) calculations guide us in the understanding of the origin of the observed anomaly, which is due to a complex magnetic coupling behavior between Mn atoms, which significantly affects the corresponding exchange interactions. The magnetocaloric properties of the Co2-xMnxB alloys show that the maximum entropy change peak temperature can be shifted between room temperature and 450 K upon variation of the manganese concentration without significant impact on the magnetocaloric response. The highest entropy change of −1.37 Jkg−1K−1 at 442 K is obtained for x = 0.1 for a field change of 2 T. This value is, however, quite low for any possible magnetocaloric or thermomagnetic power generation applications. Nevertheless, the good agreement between the advanced characterization and theory gives a deeper understanding of the Co2-xMnxB material system which can in the future be extended to other systems.

Gd-doped ZnO nanoparticles: Synthesis, structural and thermoluminescence properties

Structural and thermoluminescence (TL) properties of Gd-doped ZnO nanoparticles were investigated in the present study. TL glow curves recorded in the 10–300 K range presented three overlapped peaks around 56, 110 and 155 K for undoped ZnO nanoparticles. The Gd-doping to the ZnO nanoparticles resulted in shift of peak maximum temperatures to lower values and decrease of activation energies associated with the observed peaks. Activation energies of trapping centers were also reported. Taking into account the previously reported studies on defect characterization of ZnO compound, revealed centers were associated with interstitial defects. Structural characteristics of the synthesized nanoparticles were investigated by x-ray diffraction and scanning electron microscopy measurements.

Modelling convective heat transfer to non-spherical particles

A powder is a composition of many unique particles in almost all cases. The grains have different shapes and sizes which influence drag and heat transfer, so in multiphase flows, each particle also interacts differently with the continuous phase. In this work, a practical approach to calculate the convective in-flight heating of differently shaped, non-spherical particles, is presented. A model from literature, which uses the same parameters for the calculation of particle drag coefficients and Nusselt numbers, was selected. The model parameters were determined by simply measuring the settling velocity of multiple particles in still air. A novel method for particle classification, which has already been proven to be essential for precise drag calculations of powders with differently shaped grains, was extended for heat transfer calculations. The approach was validated by numerical calculations and experimental data of a simple test rig where the particles were heated from room temperature in free fall through hot air. After a drop height of 1.7 m, the mean particle temperature was measured with a specially developed device. The particle temperature in the test rig increased in the order of 300 K. The commercial CFD-code Ansys Fluent 17.0 in combination with an Euler-Lagrangian approach for multiphase flow calculations was used for the simulations. The numerically and experimentally determined particle temperatures agreed very well in the case of spherical and as well for non-spherical particles. In comparison to the standard model of the CFD code, which only considers spherical particles, the error in calculating the mean particle temperature was reduced from −59 K to just 2 K. Moreover, it was shown that the standard deviation of the particle temperature distribution increases significantly when the different particle shapes are included in the calculation. It was concluded that the particle classification improves the calculation of maximum and minimum particle peak temperatures. The proposed approach is fully independent of the particle type and it can be used to determine the heat transfer characteristics of various different powders. Further, the customized model can be added to nearly every CFD-code on the market and improve the results considerably while computational cost remains low due to the numerically efficient Euler-Lagrangian approach.

Experimental and numerical simulation study of the thermal hazards of four azo compounds.

Azo compounds (azos) possess diverse exothermic properties that enable their application in numerous industrial processes, but these properties also engender a corresponding diversity of thermal hazard profiles. This study employed an innovative approach to determine the specific thermal reactions and decomposition hazard profiles of azos. Four typical azos (AIBN, AMBN, ABVN, and AIBME) were assessed using three thermal calorimetry techniques, and results were subsequently analyzed using a nonlinear optimization model. Thermal hazard analysis of small-scale experiments indicated that AIBN had a heat decomposition of 1247 J/g and a maximum pressure increase of 367 psig and thus exhibited more hazardous characteristics than did AMBN, ABVN, and AIBME. This study also obtained the relevant process safety parameters, time to maximum rate, onset and peak temperature, adiabatic temperature rise, and rate of pressure increase to use for later scaled-up applications. The findings of this study can be used to develop a predictive model for the thermal behavior of azos and to provide the necessary basis for the design and selection of precise treatment and appropriate safety systems.

Comparative Study on the Microstructural and Mechanical Properties of WC-Co/AISI 1020 Steel Brazed Joint Obtained by TIG and Oxyacetylene Process

In this work, the microstructural evolution and the mechanical properties of WC-Co / AISI 1020 steel brazed joint obtained by oxyacetylene and Tungsten Inert Gas (TIG) brazing process are investigated. The maximum peak temperature induced by TIG process and the introduction of a shielding gas cause a remarkable diffusion of Co and rearrangement of WC particles along the interface with the filler alloy. The Energy Dispersive Spectroscopy (EDS) analysis reveals that the inter-diffusion activity of elements across the interfaces especially Co and Ni is more important using TIG process compared to oxyacetylene process The mechanical behavior is carried out through micro-hardness measurements and toughness tests using Vickers Indentation fracture method on the WC-Co along the parallel line of the interface with the filler alloy. The results show that the brazed joint issued from TIG process becomes increasingly hard and brittle when approaching the WC-Co/braze interface and loses its toughness (7 MPa/m1/2 compared to 15 MPA/m1/2 for oxyacetylene process) with increasing the brazing temperature.

Thermal decomposition behaviors and kinetics of carrageenan-poly vinyl alcohol bio-composite film

Pyrolysis characteristics of carrageenan-polyvinyl alcohol (CG-PVA) composite films were studied on a thermo gravimetric analyzer in N2 atmosphere. A stepwise procedure based on model-free Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Friedman-Reich-Levi (FRL) methods were applied to calculate the apparent activation energies (E). The range of E for CG-PVA/LBP/K film was 16.92∼171.53 kJ/mol. Coats-Redfern and master-plots methods were utilized to investigate the most probable mechanisms for CG-PVA/LBP/K film. Further kinetic analysis was performed and revealed that five independent parallel reactions were supposed reasonably by deconvoluting DTG curves. Kinetic parameters of the corresponding five pseudo-components for CG-PVA/LBP/K film were separately calculated via Kissinger’s method using the peak maximum temperature. It’s concluded that lignin derivatives contributed the major part of degradation process. The orders of activation energy for pseudo components are E (PVA) >E (carrageenan) >E (biomass derivatives). The comprehensive analysis of pyrolysis kinetics may expand application fields of carrageenan based biocomposite films.

Temperature lag effect on TL glow peaks: Corrections on kinetic parameters

Analyses on TL glow curves recorded with various heating rates for some ternary and quaternary crystals were accomplished using peak maximum temperatures (Tmax) which are experimentally obtained and corrected according to temperature lag effect proposed by Kitis and Tuyn. Curve fitting, initial rise, peak shape and variable heating rate methods were applied to experimental and corrected TL peaks. In spite of the fact that heating rate does not affect activation energy of a TL peak, analyses performed on the experimentally obtained TL curves resulted in an increment of the activation energy with increasing heating rate. However, as the corrected TL data were used for the analyses, the activation energy values of each TL peak recorded with different heating rate were in good agreement with each other. The detailed analyses on studied samples were given in the present paper.