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

2017 ◽  
Vol 97 ◽  
pp. 28-34 ◽  
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

scholarly journals Degradation Kinetics of Anthocyanins in Shalgam Beverage

2019 ◽  
Vol 7 (2) ◽  
pp. 282
Author(s):  
Adnan Bozdoğan ◽  
Kurban Yaşar
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Half Life ◽  
Degradation Kinetics ◽  
Production Method ◽  
Order Reaction ◽  
Different Temperatures ◽  
Traditional Production ◽  
Effects Of Temperature ◽  
Kinetics Of

This research was performed to elucidate the effects of temperature on the degradation kinetics of anthocyanins in shalgam beverage. Shalgam beverage was produced according to traditional production method. Then, it was kept at three different temperatures (65°C, 75°C, and 85°C) for 12 hours, and the relevant quantities of anthocyanins were determined thereafter. The research revealed that degradation of the anthocyanins was well described with a 1st-order reaction kinetics model and the R2 values varied in the range of 0.9059-0.9715. Activation energy of the reaction was determined to be 48537 Joule/mole. The half-lives of anthocyanins at 65°C and 75° C, and 85°C were found to be 138.63, 136.72, and 51.57, respectively. Compared the half-life periods at different temperatures, anthocyanins were found to be more resistant at 65°C and 75°C than at 85°C.

INFLUENCE OF THE CROSSLINK STRUCTURE ON THE ACTIVATION ENERGY CALCULATED UNDER THERMO-OXIDATIVE CONDITIONS

2018 ◽  
Vol 91 (1) ◽  
pp. 205-224 ◽  
Author(s):  
Richard J. Pazur ◽  
T. Mengistu
Keyword(s):  
Activation Energy ◽  
Zinc Oxide ◽  
High Temperature ◽  
Oxidation Process ◽  
Activation Energies ◽  
Structure Stability ◽  
Temperature Oxidation ◽  
Network Chain ◽  
Temperature Activation ◽  
Sulfur Donor

ABSTRACT A series of six carbon black reinforced brominated poly(isobutylene-co-isoprene) (BIIR) compounds has been developed varying only in cure system type: sulfur, sulfur donor, zinc oxide, peroxide, phenolic resin, and ionic. Compounds were aged from room temperature up to 115 °C, and hardness, mechanical properties, and network chain density were measured. Non-Arrhenius behavior was observed due to data curvature from 70 to 85 °C. The oxidation process was adequately described by assigning low (23–85 °C) and high (85–115 °C) temperature regimes. Heterogeneous aging due to diffusion limited oxygen (DLO) occurred for heat aging above 85 °C, and all measured responses except tensile strength were strongly affected, causing lower activation energies. The activation energy for the high temperature oxidation process is in the range of 107 to 133 kJ/mol in the following ascending order: zinc oxide, ionic, sulfur donor, sulfur, peroxide, and resin. The midpoint of the high temperature activation energies is of the same order as the BIIR and poly(isobutylene) elastomers. The low temperature activation energy is in the range of 55–60 kJ/mol and is likely due to a combination of oxidative chain scission (crosslink density loss) and crosslinking recombination (network building) reactions. Apart from the crosslink structure stability, the presence of unsaturation along the polymer chain after vulcanization affects the high temperature activation energy.

scholarly journals Fabrication of Friction Stir Processed Al-Ni Particulate Composite and Its Impression Creep Behaviour

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Prakrathi Sampath ◽  
Vineeth Krishna Parangodath ◽  
Kota Rajendra Udupa ◽  
Udaya Bhat Kuruveri
Keyword(s):  
Activation Energy ◽  
Creep Rate ◽  
Base Metal ◽  
Creep Behaviour ◽  
Particulate Composite ◽  
Base Plate ◽  
Xrd Analysis ◽  
Maximum Temperature ◽  
Impression Creep ◽  
Friction Stir

Nickel powders were troweled on roughened Al base plate using a friction tool made from tool steel. Friction stir processing (FSP) was carried out using a load of 8 kN and with a tool rotation speed of 800 rpm and thus a surface composite was processed. Processed samples were characterized for revealing the microstructural features. SEM and XRD analysis revealed the presence of fine Ni particles in the stir zone which lead to a significant increase in hardness. Using the “refined energy model,” the maximum temperature developed within the processed zone was estimated and found to be around 275°C. Impression creep behaviour was assessed on both the base metal and processed zone at the temperature of 30, 100, and 200°C. Creep curves were generated and steady state creep rate (SSCR) values were found out to determine the activation energy. It is observed that friction stirred regions record higher creep rate values compared to the base metal. Estimated activation energy is in the range of 6 to 16 kJ/mol. Activation energy is marginally lower in the base metal compared to friction stir processed region.

Effect of the Crystallinity on the Electromigration Resistance of Electroplated Copper Thin-Film Interconnections

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Takeru Kato ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Activation Energy ◽  
Grain Boundaries ◽  
Joule Heating ◽  
Current Density ◽  
Constant Current ◽  
Maximum Temperature ◽  
Copper Thin Film ◽  
Electroplated Copper ◽  
Low Crystallinity

Dominant factors of electromigration (EM) resistance of electroplated copper thin-film interconnections were investigated from the viewpoint of temperature and crystallinity of the interconnection. The EM test under the constant current density of 7 mA/cm2 was performed to observe the degradation such as accumulation of copper atoms and voids. Formation of voids and the accumulation occurred along grain boundaries during the EM test, and finally the interconnection was fractured at the not cathode side but at the center part of the interconnection. From the monitoring of temperature of the interconnection by using thermography during the EM test, this abnormal fracture was caused by large Joule heating of itself under high current density. In order to investigate the effect of grain boundaries on the degradation by EM, the crystallinity of grain boundaries in the interconnection was evaluated by using image quality (IQ) value obtained from electron backscatter diffraction (EBSD) analysis. The crystallinity of grain boundaries before the EM test had wide distribution, and the grain boundaries damaged under the EM loading mainly were random grain boundaries with low crystallinity. Thus, high density of Joule heating and high-speed diffusion of copper atoms along low crystallinity grain boundaries accelerated the EM degradation of the interconnection. The change of Joule heating density and activation energy for the EM damage were evaluated by using the interconnection annealed at 400 °C for 3 h. The annealing of the interconnection increased not only average grain size but also crystallinity of grains and grain boundaries drastically. The average IQ value of the interconnection was increased from 4100 to 6200 by the annealing. The improvement of the crystallinity decreased the maximum temperature of the interconnection during the EM test and increased the activation energy from 0.72 eV to 1.07 eV. The estimated lifetime of interconnections is increased about 100 times by these changes. Since the atomic diffusion is accelerated by not only the current density but also temperature and low crystallinity grain boundaries, the lifetime of the interconnections under EM loading is a strong function of their crystallinity. Therefore, it is necessary to evaluate and control the crystallinity of interconnections quantitatively using IQ value to assure their long-term reliability.

scholarly journals Effects of Surface Treatments of Montmorillonite Nanoclay on Cure Behavior of Diglycidyl Ether of Bisphenol A Epoxy Resin

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Alfred Tcherbi-Narteh ◽  
Mahesh V. Hosur ◽  
Eldon Triggs ◽  
Shaik Jelaani
Keyword(s):  
Activation Energy ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Rheological Properties ◽  
Diglycidyl Ether ◽  
Curing Temperature ◽  
Cure Behavior ◽  
Cloisite 30B ◽  
Temperature Activation ◽  
Primary Focus

Diglycidyl ether of Bisphenol A (DGEBA) based SC-15 epoxy resin was modified with three different commercially available montmorillonite (MMT) nanoclay: Nanomer I.28E and Cloisite 10A and 30B. Cure behavior of nanocomposites was studied using a variety of techniques. Primary focus of this study was to investigate influence of different surface modifications of MMT nanoclay on rheological properties and cure behavior of SC-15 epoxy resin. By adding MMT to SC-15 epoxy resin, chemistry of the epoxy is altered leading to changes in rheological properties and ultimately enthalpy and activation energy of reactions. Addition of Nanomer I.28E delayed gelation, while Cloisite 10A and 30B accelerated gelation, regardless of the curing temperature. Activation energy of reaction was lower with the addition of Nanomer I.28E and Cloisite 10A and higher for Cloisite 30B compared to neat SC-15 epoxy composite.

scholarly journals Đánh giá các giá trị năng lượng bẫy từ đường cong nhiệt huỳnh quang để phát hiện bột ớt chiếu xạ

2019 ◽  
Vol 14 (3) ◽  
pp. 140
Author(s):  
Nguyễn Duy Sang
Keyword(s):  
Activation Energy ◽  
Glow Peak ◽  
Powder Samples ◽  
Different Doses

This report presents the estimation of the activation energy (E) values from the thermoluminescence (TL) glow curves showed by the whole glow peak (WGP) method that allows us to distinguish between irradiated and non-irradiated chilli powder samples. The E values of non-irradiated samples maintain 0.65 eV whereas irradiated ones reach 0.84 eV or upper. Furthermore, the E values are obtained from the result of comparison between the chilli powder irradiated with different doses (2, 4, 6 and 8 kGy) stored for 30 days and other unknown chilli powder samples in Vietnam.

Purification and thermostability of β-galactosidase (lactase) from an autolytic strain of Streptococcus salivarius subsp. thermophilus

1989 ◽  
Vol 56 (1) ◽  
pp. 117-127 ◽  
Author(s):  
Byeong-Seon Chang ◽  
Raymond R. Mahoney
Keyword(s):  
Activation Energy ◽  
Half Life ◽  
Reaction Order ◽  
Specific Activity ◽  
Enzyme Stability ◽  
Enzyme Concentration ◽  
Lactose Hydrolysis ◽  
Streptococcus Salivarius ◽  
First Order

Summaryβ-Galactosidase from an autolytic strain of Streptococcus salivarius subsp. thermophilus was purified 109-fold to near homogeneity. The yield of purified enzyme was 41% and the specific activity was 592 0-nitrophenyl β-D-galactopyranoside U/mg at 37 °C. Two isozymes were present, but only one subunit was detected, having a mol. wt of 116000. Enzyme stability was 37–83 times greater in milk than in buffer in the range 60–65 °C. At 60 °C the half-life in milk was 146 min. Denaturation in buffer was first-order, but in milk the overall reaction order with respect to enzyme concentration was ˜ 0·5. The activation energy for denaturation was 453 kJ/mol in milk and 372 kJ/mol in buffer. In milk the activation energy for lactose hydrolysis was 35·1 kJ/mol.

Reactions with half-lives of several years

1964 ◽  
Vol 17 (4) ◽  
pp. 406 ◽  
Author(s):  
GA Bottomley ◽  
GL Nyberg
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Gas Phase ◽  
Virial Coefficient ◽  
Energy Equation ◽  
Second Virial Coefficient ◽  
First Order ◽  
First Order Kinetics ◽  
Reciprocal Temperature ◽  
Temperature Activation

The gas-phase thermal decomposition of dimethyldiazirine, (CH3)2CN2, at very slow rates has been investigated using precision gas-volumetric techniques previously applied to second virial coefficient studies. At 50-70� the first-order kinetics correspond to half-lives about 0.3-3.0 years. The present results, together with data obtained by other workers using conventional apparatus at 124-174�, fit a single log rate-reciprocal temperature activation energy equation.

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