Thermochimica Acta最新文献_第2页

DSC to explore activation energy landscape of glass relaxation

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-15 DOI: 10.1016/j.tca.2025.179985

Sergey Vyazovkin

{"title":"DSC to explore activation energy landscape of glass relaxation","authors":"Sergey Vyazovkin","doi":"10.1016/j.tca.2025.179985","DOIUrl":"10.1016/j.tca.2025.179985","url":null,"abstract":"<div><div>This review paper discusses the methods of estimating the activation energy of the glass relaxation from DSC experiments that include heating through the glass transition, short time annealing (physical aging) far below <em>T<sub>g</sub></em>, and annealing into equilibrium just below <em>T<sub>g</sub></em>. Isoconversional analysis of the data obtained on heating through the glass transition yields large (hundreds kJ/mol) activation energy that decreases with increasing temperature as expected for the alpha relaxation. Short time annealing runs conducted around 0.8<em>T<sub>g</sub></em> give rise to small (tens kJ/mol) activation energies, whose values are similar to those of the beta relaxation. Increasing the annealing temperature in the region 0.8<em>T<sub>g</sub></em> – <em>T<sub>g</sub></em> causes the activation energy to rise toward the values characteristic of the alpha relaxation that suggests that the overall relaxation in the respective temperature region is driven by the mixed dynamics that comprises the alpha and beta processes. As temperature rises from well below to well above <em>T<sub>g</sub></em> the activation energy passes through a maximum around <em>T<sub>g</sub></em>. The mixed relaxation dynamics is also observed on annealing into equilibrium that demonstrates that with the progress of relaxation the activation energy increases between the values characteristic of the beta and alpha relaxation.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"748 ","pages":"Article 179985"},"PeriodicalIF":3.1,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Isoconversional kinetic analysis of bisphenol A benzoxazine cure

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-15 DOI: 10.1016/j.tca.2025.179984

Vyacheslav V. Shutov, Ekaterina A. Gorbunova, Irina Yu. Gorbunova, Igor S. Sirotin

引用次数: 0

Thermal parameter investigation of nanocrystalline BN particles under the neutron irradiation

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-15 DOI: 10.1016/j.tca.2025.179982

Elchin M. Huseynov , Tural G. Naghiyev , Nijat R. Abbasov

{"title":"Thermal parameter investigation of nanocrystalline BN particles under the neutron irradiation","authors":"Elchin M. Huseynov , Tural G. Naghiyev , Nijat R. Abbasov","doi":"10.1016/j.tca.2025.179982","DOIUrl":"10.1016/j.tca.2025.179982","url":null,"abstract":"<div><div>The thermal properties of nanocrystalline boron nitride (BN) particles are crucial for their use in high-temperature and radiation-resistant applications. However, the effects of neutron irradiation on these properties remain poorly understood. This study aims to investigate the thermal behavior of nanocrystalline BN particles before and after exposure to neutron irradiation, with a focus on changes in key thermo-physical parameters. To achieve this, we employed differential scanning calorimetry (DSC) to determine the Gibbs free energy of BN nanoparticles across a temperature range of 300 K to 1270 K. Differential thermal analysis (DTA) was also used to examine phase transitions and potential amorphization processes that occur in the particles post-irradiation. Both enthalpy and entropy were calculated for the nanocrystalline BN system before and after neutron irradiation, with the results supported by theoretical models. Our findings reveal significant changes in the thermal properties of BN nanoparticles induced by neutron irradiation, including shifts in phase behavior and alterations in the thermodynamic parameters. These results provide a deeper understanding of the material's behavior under neutron irradiation, which is critical for optimizing the use of BN in nuclear and other high-radiation environments.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"748 ","pages":"Article 179982"},"PeriodicalIF":3.1,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of gas phase products and free radical formation mechanism in anthracite spontaneous combustion process

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-14 DOI: 10.1016/j.tca.2025.179981

Dan Zhao , Yumo Wu , Jinzhang Jia

{"title":"Analysis of gas phase products and free radical formation mechanism in anthracite spontaneous combustion process","authors":"Dan Zhao , Yumo Wu , Jinzhang Jia","doi":"10.1016/j.tca.2025.179981","DOIUrl":"10.1016/j.tca.2025.179981","url":null,"abstract":"<div><div>Understanding the microstructure of coal is fundamental to elucidating the reaction pathways involved in spontaneous combustion. In this study, we employed simultaneous thermal analysis (TG-DSC), thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR), in-situ FTIR, and EPR(Electron Paramagnetic Resonance) to investigate the combustion behavior of anthracite. A molecular model for anthracite (C<sub>200</sub>H<sub>132</sub>O<sub>14</sub>N<sub>2</sub>S<sub>1</sub>) was developed through characterization and analytical experiments, followed by ReaxFF molecular dynamics simulations of combustion at varying temperatures. The results indicate that the oxidation reactions of active functional groups serve as the primary contributor to the oxidation and thermal storage processes of anthracite. The sequence of gas phase products generation is H<sub>2</sub>O > CO<sub>2</sub> > CO, with CO<sub>2</sub> being produced in the highest quantity, followed by H<sub>2</sub>O, while CO is generated in the least amount. Furthermore, the reaction pathways for gas phase products are significantly influenced by free radicals such as ·CHO, ·HO, and ·H.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"748 ","pages":"Article 179981"},"PeriodicalIF":3.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143645094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Henkin-McGill critical temperature test for explosives revisited: An overview of historical and modern method development

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-10 DOI: 10.1016/j.tca.2025.179980

Jason J. Phillips

{"title":"The Henkin-McGill critical temperature test for explosives revisited: An overview of historical and modern method development","authors":"Jason J. Phillips","doi":"10.1016/j.tca.2025.179980","DOIUrl":"10.1016/j.tca.2025.179980","url":null,"abstract":"<div><div>Many overarching standards, regulations, or other requirements necessitate that the critical temperature (T<sub>crit</sub>) of an energetic material be known or estimate prior to operations such as heating. However, they rarely, if ever, provide a specific method for doing so. While other methods exist to calculate T<sub>crit</sub>, such as the Frank-Kamenetskii equation, computer simulation, etc., these cannot be readily utilized for energetics that are physical mixtures (i.e. most pyrotechnics) or materials where detailed material properties required for such calculations are lacking.</div><div>In this study, a COTS (commercial off-the-shelf) SBAT (Simulated Bulk Auto-ignition Test) apparatus is modified to perform Henkin cookoff tests. This creates a simple, efficient, and cost-effective solution to estimate required T<sub>crit</sub> values for energetic materials. After a historical overview of the evolution of the Henkin test, several common energetic materials (PETN, RDX, etc.) for which T<sub>crit</sub> has been readily calculated, and historical data is available, were analyzed for comparison and verification purposes. This was followed by a variety of pyrotechnic mixtures and other materials to where calculation methods cannot be readily used. The modified apparatus, as well as an updated sample shell sealing method, produced results that aligned well with historical data. It also produced reasonable T<sub>crit</sub> estimates for those materials where the Frank-Kamenetskii equation cannot be applied.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"748 ","pages":"Article 179980"},"PeriodicalIF":3.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143645093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Insight into the solid-liquid equilibrium behavior and apparent thermodynamic analysis of polymorphic pregnenolone (Form Ⅰ) in thirteen neat solvents

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-08 DOI: 10.1016/j.tca.2025.179979

Jixiu Deng , Pengshuai Zhang , Han Sun, Rongrong Wang, Binbin Wu, Yuemei Li, Beibei Feng, Haowei Sun, Shuoye Yang

{"title":"Insight into the solid-liquid equilibrium behavior and apparent thermodynamic analysis of polymorphic pregnenolone (Form Ⅰ) in thirteen neat solvents","authors":"Jixiu Deng , Pengshuai Zhang , Han Sun, Rongrong Wang, Binbin Wu, Yuemei Li, Beibei Feng, Haowei Sun, Shuoye Yang","doi":"10.1016/j.tca.2025.179979","DOIUrl":"10.1016/j.tca.2025.179979","url":null,"abstract":"<div><div>This study aimed to investigate the solubility and dissolution thermodynamics of pregnenolone (Form I) in <em>n</em>-propanol, N-Methyl-2-pyrrolidone (NMP), ethyl acetate, 2-methoxyethanol, ethyl formate, <em>n</em>-butanol, 2-butoxyethanol, N, N-Dimethylformamide (DMF), 2-propoxyethanol, <em>i</em>-propanol, ethanol, 2-ethoxyethanol and methanol from 283.15 K to 323.15 K by a laser dynamic method. The experimental solubility of pregnenolone (Form I) was successfully fitted using five thermodynamic models (Jouyban, Apelblat, NRTL, van't Hoff, UNIQUAC), and the van't Hoff equation provided the best prediction effect with a minimum average <em>RAD</em> (relative average deviation) of 1.00 × 10<sup>–2</sup> and <em>RMSD</em> (root mean square deviation) of 6.58 × 10<sup>–5</sup>. Hansen solubility parameter (HSPs) was used to evaluate the dissolution behavior including the solubility order of pregnenolone (Form I). The apparent thermodynamics were evaluated, and results showed that entropy was the main driving force during the dissolution process of pregnenolone (Form I).</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"748 ","pages":"Article 179979"},"PeriodicalIF":3.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143681448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental study on the oxidation characteristics of coal under the action of water and MgCl2

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-07 DOI: 10.1016/j.tca.2025.179978

Zongxiang Li , Cheng Wang , Cong Ding , Lin Li , Shuoran Huang , Ji Wu

引用次数: 0

Research progress and prospects of CO2 fire prevention and extinguishing technology in mine goafs 矿井巷道二氧化碳防灭火技术的研究进展与展望

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-06 DOI: 10.1016/j.tca.2025.179977

Liwen Guo , Huizhu Du , Xiao Cui , Jiayong Zhang , Kai Wang , Jianguo Wu , Haijun Guo

{"title":"Research progress and prospects of CO2 fire prevention and extinguishing technology in mine goafs","authors":"Liwen Guo , Huizhu Du , Xiao Cui , Jiayong Zhang , Kai Wang , Jianguo Wu , Haijun Guo","doi":"10.1016/j.tca.2025.179977","DOIUrl":"10.1016/j.tca.2025.179977","url":null,"abstract":"<div><div>As coal mining continues to deepen, the issue of goaf fires has become increasingly prominent, posing a significant threat to mine safety and the ecological environment. Understanding carbon dioxide (CO<sub>2</sub>) fire prevention and extinguishing technology is crucial for preventing and controlling goaf fires. This paper explores the mechanisms of CO<sub>2</sub> fire prevention and extinguishing, including inertization and asphyxiation, adsorption inhibition, cooling, and explosion suppression. Additionally, it analyzes the impact of CO<sub>2</sub> injection locations and volume on fire prevention and extinguishing effectiveness, and outlines the advantages of using CO<sub>2</sub> for fire prevention and extinguishing. Furthermore, the paper proposes future research directions, such as optimizing CO<sub>2</sub> injection parameters, utilizing the Internet of Things to achieve intelligent management of CO<sub>2</sub> fire prevention and extinguishing, and exploring the synergistic application of CO<sub>2</sub> fire prevention and extinguishing technology with other technologies. These efforts aim to drive innovation and development in CO<sub>2</sub> fire prevention and extinguishing technologies, providing more efficient and sustainable solutions for coal mine safety.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"747 ","pages":"Article 179977"},"PeriodicalIF":3.1,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143594092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermophysical properties of Co–Si melts measured by an electrostatic levitation technique

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-06 DOI: 10.1016/j.tca.2025.179976

Manabu Watanabe , Yuki Watanabe , Takehiko Ishikawa , Chihiro Koyama

引用次数: 0

Experimental study on thermokinetic characteristics of multiple coal seams in Xinjiang open pit mine using thermogravimetric–Fourier transform infrared spectroscopy and thermogravimetric–mass spectrometry

IF 3.1 2区化学

Thermochimica Acta Pub Date : 2025-03-01 DOI: 10.1016/j.tca.2025.179973

Jianling Zang , Wei Sun , Zhenkai Yang , Zhijie Ding , Meng Dong , Shengjie Jiang , Yongheng Gui , Hailin Jia

{"title":"Experimental study on thermokinetic characteristics of multiple coal seams in Xinjiang open pit mine using thermogravimetric–Fourier transform infrared spectroscopy and thermogravimetric–mass spectrometry","authors":"Jianling Zang , Wei Sun , Zhenkai Yang , Zhijie Ding , Meng Dong , Shengjie Jiang , Yongheng Gui , Hailin Jia","doi":"10.1016/j.tca.2025.179973","DOIUrl":"10.1016/j.tca.2025.179973","url":null,"abstract":"<div><div>This study focuses on the coal spontaneous combustion in the open-pit mining of multiple coal seams in Dananhu No.2 Mine. Experimental research was conducted on the characteristics and thermokinetics of coal spontaneous combustion oxidation. A synchronous thermal analysis thermogravimetric (TG)-differential scanning calorimetry(DSC)- Fourier transform infrared spectroscopy (FTIR), thermogravimetric(TG)-mass spectrometry (MS) combined system was used to analyze the mass variation, gaseous product, functional group and other parameters of coal spontaneous combustion. The results of TG-DTG-DSC analysis indicate that different heating rates affect the characteristic temperature points and thermal weight loss process of coal spontaneous combustion. A significant change in the reaction kinetics mechanism of the coal spontaneous combustion process. The relationship between the apparent activation energy and the pre-exponential factor in coal spontaneous combustion indicates that the pre-exponential factor positively correlates with the apparent activation energy. These findings are crucial for a deeper understanding of the coal spontaneous combustion process.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"747 ","pages":"Article 179973"},"PeriodicalIF":3.1,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0