The shift of the thermoluminescence peak maximum temperature versus heating rate, trap filling and trap emptying: Predictions, experimental verification and comparison

Clays are very important raw materials in the manufacturing of traditional ceramic products. The present study was intended to study the phase transformations of smectites submitted to thermal treatment in conventional stove, applying slow and fast cycles. We used three clays, two national and one imported, which were beneficiated and characterized by mineralogical analysis. Later, they were submitted to a thermal treatment at 1100, 1200 and 1250°C, with heating rate of 5 and 30°C/min, remaining under the maximum temperature for 60 minutes. We observed the presence of mullite peaks starting at 1100°C for all samples. It was verified that the sample with the highest alumina/silica ratio presented more intense mullite peaks, and the sample with the high MgO content, besides the mullite phase, also formed cordierite.

Download Full-text

HEATING RATE EFFECTS ON THERMOLUMINESCENCE OF BaSO4:Eu+PTFE PREPARED AT ININ-MEXICO

Modern Physics Letters B ◽

10.1142/s0217984910022834 ◽

2010 ◽

Vol 24 (08) ◽

pp. 717-726 ◽

Cited By ~ 5

Author(s):

P. R. GONZALEZ ◽

C. FURETTA ◽

E. CRUZ-ZARAGOZA ◽

J. AZORÍN

Keyword(s):

Heating Rate ◽

Sequential Quadratic Programming ◽

Glow Curve ◽

Frequency Factor ◽

Glow Peak ◽

Maximum Temperature ◽

Kinetics Parameters ◽

Rate Effects ◽

Higher Temperature ◽

Reading System

In this work, we show the influence of heating rate (H.R.) on the thermoluminescence (TL) signal of BaSO 4 activated by Eu ions. The maximum temperature, the TL integral, the activation energy, the frequency factor and full width at half maximum of the TL glow-peak as a function of the H.R. were studied. The TL reading system used was a Harshaw TL reader model 4000, with constant H.R. in the range from 2 to 12 K/s. The irradiation dose was 0.1 Gy from 60 Co in all cases. The kinetic parameters and their dependence on the H.R. were evaluated using the sequential quadratic programming glow curve deconvolution (SQPGCD). The experimental results showed that as the H.R. increases, the IM shifts to higher temperature; similar behavior of the kinetics parameters were obtained.

Download Full-text

New expressions for half life, peak maximum temperature, activation energy and kinetic order of a thermoluminescence glow peak based on the Lambert W function

Radiation Measurements ◽

10.1016/j.radmeas.2016.12.013 ◽

2017 ◽

Vol 97 ◽

pp. 28-34 ◽

Cited By ~ 3

Author(s):

George Kitis ◽

Vasilis Pagonis

Keyword(s):

Activation Energy ◽

Half Life ◽

Glow Peak ◽

Lambert W Function ◽

Maximum Temperature ◽

Kinetic Order ◽

Peak Maximum ◽

Temperature Activation

Download Full-text

Effect of Heating Rate on the Responses of LiF: Mg, Cu, Na, Si Thermoluminescent Phosphor

Communications in Physics ◽

10.15625/0868-3166/21/1/91 ◽

2011 ◽

Vol 21 (1) ◽

pp. 43 ◽

Cited By ~ 1

Author(s):

Vu Thi Thai Ha ◽

Nguyen Thi Quy Hai ◽

Nguyen Ngoc Long

Keyword(s):

Heating Rate ◽

Peak Height ◽

Glow Peak ◽

Maximum Temperature ◽

Full Width ◽

Half Maximum ◽

Temperature Peak ◽

Heating Rates ◽

First Order ◽

Area Increase

In the current work the glow curves for LiF:Mg,Cu,Na,Si thermoluminescent material were measured and analyzed by using a function approximating to the well-known Randall-Wilkins first-order expression. The influence of different heating rates on thermoluminescent glow-peak maximum temperature, peak height and integrated area of the glow peak was investigated for LiF:Mg,Cu,Na,Si phosphor. The results show that the glow-peak temperature, peak height and glow peak area increase with increasing heating rate, while the full width at half maximum of glow peak almost keeps constant in the range of heating rates studied.

Download Full-text

Experimental Research on Molding Biomass’s Carbonization Homogeneity

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.634-638.759 ◽

2013 ◽

Vol 634-638 ◽

pp. 759-763

Author(s):

Wei Hu ◽

Jian Hang Hu ◽

Hua Wang ◽

Kun Sang ◽

Juan Qin Li ◽

...

Keyword(s):

Mass Transfer ◽

Heating Rate ◽

Temperature Difference ◽

Small Dimension ◽

Carbonization Temperature ◽

Maximum Temperature ◽

Exothermic Effect ◽

Pyrolysis Process ◽

Heating Rates ◽

Maximum Temperature Difference

Molding biomass’s carbonization homogeneity was studied through doing research on temperature difference of surface and inside of biomass by making experiments. Molding biomass’s size is larger than that of small dimension biomass and carbonization in whole biomass is different to some extent. But endothermic and exothermic effect in pyrolysis process and mass transfer of volatile are beneficial to carbonization homogeneity. When biomass average heating rate becomes larger, the maximum temperature difference of surface and inside becomes larger, besides that the temperature of biomass is higher when molding biomass’s carbonization is homogeneous. Maximum temperature differences were 30, 76, 137 °C respectively when biomass average heating rates were 5, 10, 20 °C/min. In order to ensure homogeneity, carbonization should reach the temperature which lignin decomposes strongly at releasing heat violently. Carbonization temperature should be higher than 450 °C. Besides, biomass average heating rate shouldn’t be too high and it should be under 20 °C /min.

Download Full-text

Experimental Investigations on the Temperature Increase of Ultra-High Performance Concrete under Fatigue Loading

Applied Sciences ◽

10.3390/app9194087 ◽

2019 ◽

Vol 9 (19) ◽

pp. 4087 ◽

Cited By ~ 2

Author(s):

Melchior Deutscher ◽

Ngoc Linh Tran ◽

Silke Scheerer

Keyword(s):

Fatigue Strength ◽

Heating Rate ◽

Temperature Increase ◽

High Performance ◽

High Performance Concrete ◽

Fatigue Behavior ◽

Fatigue Loading ◽

Maximum Temperature ◽

Experimental Investigations ◽

Resource Saving

Leaner, more filigree, and resource-saving constructions are the development goal of the in the building industry. In reinforced concrete construction, a ultra-high strength concrete was developed to achieve these goals. Due to its use and requirements, this very pressure-resistant material is no longer only exposed to static loads. In applications such as wide-span bridges, machine foundations and wind turbines, the susceptibility to vibration is also significant. Research into the fatigue behavior of the new building material is therefore very important. In this article we will discuss the effect of heating up of high performance concretes under fatigue stress. The thesis is that warming up, which was already observed by several research groups, has an influence on the fatigue strength. Changes in the strength of the concrete or residual stresses generated by heating can lead to early failure. The aim is to find the reasons for the heating and the grade of influence on the fatigue strength. A systematic test program was developed to investigate the influencing parameters maximum stress level, frequency, and maximum grain size of the concrete. Thirty fatigue tests were carried out; the results will be presented here. The influence on the temperature increase as well as on the heating rate for the individual parameters will be discussed. The results show that all three discussed parameters have a significant influence on the temperature rise. Whereas the maximum temperature reached depends strongly on the frequency, the other two parameters mainly influence the heating rate.

Download Full-text

Exoskeleton may influence the internal body temperatures of Neotropical dung beetles (Col. Scarabaeinae)

PeerJ ◽

10.7717/peerj.3349 ◽

2017 ◽

Vol 5 ◽

pp. e3349 ◽

Cited By ~ 11

Author(s):

Valentina Amore ◽

Malva I.M. Hernández ◽

Luis M. Carrascal ◽

Jorge M. Lobo

Keyword(s):

Body Temperature ◽

Heating Rate ◽

Solar Irradiance ◽

Infrared Radiation ◽

Thermal Control ◽

Dung Beetles ◽

Maximum Temperature ◽

Heating Process ◽

Heat Gain ◽

Internal Body

The insect exoskeleton is a multifunctional coat with a continuum of mechanical and structural properties constituting the barrier between electromagnetic waves and the internal body parts. This paper examines the ability of beetle exoskeleton to regulate internal body temperature considering its thermal permeability or isolation to simulated solar irradiance and infrared radiation. Seven Neotropical species of dung beetles (Coleoptera, Scarabaeinae) differing in colour, surface sculptures, size, sexual dimorphism, period of activity, guild category and altitudinal distribution were studied. Specimens were repeatedly subjected to heating trials under simulated solar irradiance and infrared radiation using a halogen neodymium bulb light with a balanced daylight spectrum and a ceramic infrared heat emitter. The volume of exoskeleton and its weight per volume unit were significantly more important for the heating rate at the beginning of the heating process than for the asymptotic maximum temperature reached at the end of the trials: larger beetles with relatively thicker exoskeletons heated more slowly. The source of radiation greatly influences the asymptotic temperature reached, but has a negligible effect in determining the rate of heat gain by beetles: they reached higher temperatures under artificial sunlight than under infrared radiation. Interspecific differences were negligible in the heating rate but had a large magnitude effect on the asymptotic temperature, only detectable under simulated sun irradiance. The fact that sun irradiance is differentially absorbed dorsally and transformed into heat among species opens the possibility that differences in dorsal exoskeleton would facilitate the heat gain under restrictive environmental temperatures below the preferred ones. The findings provided by this study support the important role played by the exoskeleton in the heating process of beetles, a cuticle able to act passively in the thermal control of body temperature without implying energetic costs and metabolic changes.

Download Full-text

Application of the Artificial Neural Network (ANN) Approach for Prediction of the Kinetic Parameters of Lignocellulosic Fibers

Textiles ◽

10.3390/textiles1020013 ◽

2021 ◽

Vol 1 (2) ◽

pp. 258-267

Author(s):

Heitor Luiz Ornaghi ◽

Roberta Motta Neves ◽

Francisco M. Monticeli

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Kinetic Parameters ◽

Heating Rate ◽

Maximum Temperature ◽

Heating Rates ◽

Science Field ◽

Lignocellulosic Fibers ◽

Artificial Neural ◽

Artificial Neural Network Ann

Lignocellulosic fibers are widely applied as reinforcement in polymer composites due to their properties. The thermal degradation behavior governs the maximum temperature at which the fiber can be applied without significant mass loss. It is possible to determine this temperature using Thermogravimetric Analysis (TG). In particular, when curves are obtained at different heating rates, kinetic parameters can be determined by using Arrhenius-based equations, and more detailed characteristics of the material are obtained. However, every curve obtained at a distinct heating rate demands material, cost and time. Methods to predict thermogravimetric curves can be very useful in the materials science field, and in this sense, mathematical approaches are powerful tools, if well employed. For this reason, in the present study, thermogravimetric curves from curaua fiber were obtained at four different heating rates (5, 10, 20 and 40 °C·min−1) and Vyazovkin kinetic parameters were obtained using free available software. After, the experimental curves were fitted using an artificial neural network (ANN) approach followed by a Surface Response Methodology (SRM) aiming to obtain curves at any heating rate between the minimum and maximum experimental heating rates. Finally, Vyazovkin kinetic parameters were tested again, with the new predicted curves at the heating rates of 7, 15, 30 and 50 °C·min−1. Similar values of the kinetic parameters were obtained compared to the experimental ones. In conclusion, due to the capability to learn from the own data, ANN combined with SRM seems to be an excellent alternative to predict TG curves that do not test experimentally, opening the range of applications.

Download Full-text

Application of the Artificial Neural Network (ANN) Approach for Prediction of the Kinetic Parameters of Lignocellulosic Fibers

10.20944/preprints202105.0561.v1 ◽

2021 ◽

Author(s):

Heitor Luiz Ornaghi Júnior ◽

Roberta Motta Neves ◽

Francisco Maciel Monticeli

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Kinetic Parameters ◽

Heating Rate ◽

Maximum Temperature ◽

Heating Rates ◽

Science Field ◽

Lignocellulosic Fibers ◽

Artificial Neural ◽

Artificial Neural Network Ann

Lignocellulosic fibers are widely applied as composite reinforcement due to their properties. The thermal degradation behavior determines the maximum temperature in which the fiber can be applied without significant mass loss. It is possible to determine these temperatures using Thermogravimetric Analysis (TG). In particular, when curves are obtained at different heating rates, kinetic parameters can be determined and more detailed characteristics of the material are obtained. However, every curve obtained at a distinct heating rate demands material, cost, and time. Methods to predict thermogravimetric curves can be very useful in the materials science field and in this sense mathematical approaches are powerful tools if well employed. For this reason, in the present study, curaua TG curves were obtained at three different heating rates (5, 10, 20, and 40 °C.min-1) and Vyazovkin kinetic parameters were obtained. After, the experimental curves were fitted using an artificial neural network (ANN) approach followed by a Surface Response Methodology (SRM). Curves at any heating rate between the minimum and maximum experimental heating rates were obtained with high reliability. Finally, Vyazovkin kinetic parameters were tested again with the new curves showing similar kinetic parameters from the experimental ones. In conclusion, due to the capability to learn from the own data, ANN combined with SRM seems to be an excellent alternative to predict TG curves that do not test experimentally, opening the range of applications.

Download Full-text