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The effects of different hot air speeds and temperatures on the drying characteristics of half-ripe rice paper were investigated by hot air convection drying experiments. The thin-layer drying experiments were carried out at three different combinations of air speeds of 1.97 m/s, 3.00 m/s, and 3.90 m/s and temperatures of 85 °C, 100 °C and 115 °C. The results show that among the 10 drying kinetic models selected, the Modified Page model is the most suitable model to describe the drying characteristics of the thin layer of half-ripe rice paper; the whole drying process exists obvious ascending, constant and descending processes; the effective moisture diffusion coefficient of half-ripe rice paper is in the range of 1.52656 × 10−9 m2/s–3.15816 × 10−9 m2/s, whose size increases with the increase of the hot wind speed and temperature. Its magnitude increases with the increase of wind speed and temperature; the drying activation energy of half-ripe rice paper is 6.55 kJ/mol calculated by Arrhenius equation. [ABSTRACT FROM AUTHOR]

Tetra Pak® paper and PE (polyethylene) wastes were evaluated to obtain a new composite material with awareness of environmental responsibility. Fillers and coupling agents were used for this joining process. Calcite (CaCO3), boric acid (H3BO3), SPT (Sodium Perborate Tetrahydrate / NaBO3.4H2O), titanate, MAPE (maleic anhydride grafted polyethylene, and vinyltriethoxysilane (C8H18O) composites were produced in 30 x 30 cm plates. A total of 30 samples were prepared as 5 mg flour for thermogravimetric analysis (TGA). Samples were observed in a thermal analyzer at 10, 15, or 20 °C/min heating rate in nitrogen atmosphere. Graphs were obtained as a result of TGA, and the activation energies were calculated using these graphs. The activation energy was calculated using the Flynn-Wall-Ozawa method. The determined activation energies of the composites were close to each other for each temperature group. In the samples using calcite and vinyltriethoxysilane, relatively higher activation energies were observed in comparison to the samples with boric acid and MAPE. [ABSTRACT FROM AUTHOR]

This paper studies the pyrolysis mechanisms of Nomex insulation paper in nitrogen and air atmospheres. The Nomex insulation paper is composed of 93% poly (m-phenylene isophthalamide) (PMIA) fibers and 7% inorganic substances based on elemental analysis. Using the thermogravimetry, it is found that the pyrolysis behaviors in nitrogen and air are similar below 770 K, with large discrepancies identified in the temperature range of 770–1073 K. The peak mass loss rate in air is 9 times higher than that in nitrogen. The kinetic analysis shows that the average activation energy (E ) in air is lower than that in nitrogen by 32% when the temperature is higher than 770 K, indicating a lower thermal stability. The PMIA fibers are found decomposing more seriously in air using SEM. Below 770 K, the functional groups of two atmospheres are mainly produced by the breakage of amide bonds and formation of aromatic nitrile. Unlike nitrogen, the organic substances in the solid residue are mostly oxidized at 1073 K in air. Consequently, the maximum productions of H2O, CO2 and CO in air are nearly 5 times higher than those of nitrogen, and the HCN generated during pyrolysis is further oxidized to NOx in air. Combining with the results of Py-GC/MS, it is inferred that the small molecules generated by the degradation of PMIA molecular chains, especially the benzene rings, will experience oxidization reactions in air atmosphere, with large amounts of H2O, CO2, CO and NOx produced. [ABSTRACT FROM AUTHOR]

In this study, practical application for the industrial-scale hydrogen evolution reaction (HER) process is established using sustainable Cu 2 CoSnS 4 embedded in paper-working electrodes. The Cu 2 CoSnS 4 is produced using a solvent-free solid-phase approach. The effect of a wide pH range of electrolytes on working electrodes for hydrogen evolution reactions is also investigated. The Cu 2 CoSnS 4 embedded paper-working electrodes exhibit goodelectrocatalytic activity for hydrogen evolution reaction with low overpotential values of 233, 310, and 261 mV vs RHE at 10 mA/cm 2 in 0.5 M H 2 SO 4 ,1 M KOH, and 1 M PBS, respectively. These designed electrodes exhibit high double-layer capacitance and electrochemical surface area for a wide pH range. In acidic, alkaline and neutral environments, the catalyst-embedded paper electrodes explicit high turnover frequencies of 2.15 s−1, 2.75 s−1, and 2.11 s−1, respectively. The temperature-dependent hydrogen evolution reaction is studied to calculate the activation energy of the cathodic electrode. Utilising chrono-amperometry for about 118 h in an acidic media, which shows that electrodes have a high degree of stability. In comparison to other previously reported work on catalyst-embedded electrodes, the Cu 2 CoSnS 4 embedded paper-working electrodes offer excellentpotential for HER activity across a wide pH range and are suitable for industrial application. • Cu 2 CoSnS 4 embedded paper working electrodes are developed for hydrogen generation. • The electrodes exhibit universal pH hydrogen evolution reaction. • Electrodes shows excellent stability upto 40hr for continuous hydrogen generation. • The electrode displays good stability at current density more than 200 mA/cm2. [ABSTRACT FROM AUTHOR]

Thermal annealing is a convenient, low-cost, and versatile route to fine-tune the physicochemical properties of graphene oxide paper (GOP) toward various applications. Therefore, a thorough monitoring of the thermal decomposition of GOP is generally required for a precise and safe adjustment of its properties. From this perspective, thermogravimetry analysis (TG-A) is employed to scrutinize the multi-step thermal decomposition process of GOP under a nitrogen atmosphere. GOP is elaborated from modified hummers graphene oxide (GO). Nonisothermal TG-A is carried out for the as-prepared GOP at different heating rates. Activation energy is assessed for the overall decomposition process by several isoconversional models. Derivative thermogravimetry (D-TG) curves are derived numerically from TG-A data. To find the number of reactions involved, D-TG curves are deconvoluted into individual peaks by the well-known Fraser–Suzuki function. The obtained results show that the thermal decomposition of GOP consists mainly of six reactions: physisorbed water dehydration, rearrangement and elimination of oxygen functional groups, disproportionation reaction, chemisorbed water dehydration, desulfonation, and degradation of the carbon framework. Furthermore, kinetic triplets for each of the individual reactions are figured out by coupling the Vyazovkin nonlinear method with the compensation effect. [ABSTRACT FROM AUTHOR]

Organic-rich pulp and paper mill sludge (PPMS) has the potential to become a renewable carbon source for producing alternatives to fossil-based product. In this work, PPMS treated by hydrothermal carbonization (HTC) was investigated based on its pyrolysis properties. The pyrolytic mechanism, kinetics data and product of the sample were studied using TG as well as pyrolysis tests in Py-GC/MS and a bench-scale reactor at 450, 550, and 650 °C. The results show that the thermal decomposition of feedstock is a two-stage reaction. The mean activation energy of the pyrolysis of HTC treated PPMS was estimated as 233.08 kJ/mol, which is higher than that of the pyrolysis of paper sludge reported before. The changes in enthalpies, entropies and Gibbs free energies from the reactants to the activated complex were estimated. The concentration of monocyclic aromatic hydrocarbons in the derived organic liquid fraction shows a positive correlation with the pyrolysis temperature. At 550 °C, the organic liquid fraction reached its highest yield at 13.7% with an oxygen level of 10.7 wt% and a higher heating value of 35.9 MJ/kg. The pyrolytic chars show that a molar ratio of O:C is less than 0.2, which shows potential for use as a carbon sink. • Multi-scale study of pyrolysis behaviour of paper sludge. • Δ H ǂ, Δ G ǂ, and Δ S ǂ of pyrolysis reactions are studied on TG. • Detailed components analysis of the pyrolytic vapor on Py-GC/MS. • Comprehensive evaluation of pyrolysis product from bench-scale reactor. [ABSTRACT FROM AUTHOR]

The diffusion of moisture in the meta-aramid fiber (PMIA) oil-paper insulation system and the thermal decomposition of PMIA insulation paper in different moisture contents were studied via molecular dynamics simulations. The results showed that the PMIA insulation paper had a stronger ability to absorb water molecules than the insulating oil; therefore, water molecules in the insulating oil diffuse to the insulation paper, which further affects the thermal decomposition of the PMIA insulation paper. The activation energy of the water-bearing composite model was 129.96 kJ/mol, which was 5.5% lower than that of the pure PMIA (137.61 kJ/mol). It indicated that moisture could promote PMIA decomposition. The micromechanism of the enhanced thermal decomposition of PMIA with moisture contents could be described as follows: The O–H bond of the water can easily break to generate H atoms and hydroxyl radicals (•OH). The strong activity of H atoms allows it to easily combine with the ammonia base at the end of PMIA to generate NH3. Additionally, the free •OH radical can easily combine with the amido and carbonyl bonds at two ends of PMIA, undergo an oxidation reaction, and generate an oxhydryl. Therefore, it can reduce the chemical stability of the PMIA chain and further drive thermal decomposition. Statistical data on fragments generated by the thermal decomposition of the water-bearing PMIA composite system show that the main products include H2, C/H/O-containing molecules, hydrocarbon molecules, N-bearing molecules, and free radicals. [ABSTRACT FROM AUTHOR]

Frequency Domain Spectroscopy (FDS) is widely used to estimate oil–paper insulation. The high moisture and long aging change the FDS characteristics of the insulating oil–paper, so normalization processing is required. Still, the choice of single activation energy needs further research. This paper studies the FDS characteristic of oil–paper insulation samples with different moisture and aging degrees and improves the traditional temperature correction method. The enhanced Arrhenius model uses the segmented activation energy to make the normalized FDS curve coincide better with the target curve, and the error is reduced. In addition, to verify the method's effectiveness, this paper proposes an iterative correction process. It corrects the tan δ-f curve of the bushing with an aging time of 800 h based on segmented activation energy, and the overall normalization effect is improved. [ABSTRACT FROM AUTHOR]

The thin-layer drying performance for a typical solid waste (paper towel) was evaluated at hot air temperatures of 90–130 °C (0.5 m/s air velocity) and microwave powers of 200–800 W in a bench-scale microwave combined convective drying setup. Influences of hot air and radiation modes (multi-magnetron and mode stirrer) on the temperature distribution uniformity were examined. The effective moisture diffusivities of sample during pure hot air drying ranged from 6.07 × 10−9 to 1.31 × 10−8 m2/s, while those for pure microwave drying were from 3.54 × 10−8 to 1.52 × 10−7 m2/s. The apparent activation energy of sample in pure hot air drying was estimated as 23.17 kJ/mol, while that for pure microwave drying was 22.64 W/g. The effective moisture diffusivities of sample in combined drying ranged from 5.71 × 10−8 to 2.05 × 10−7 m2/s. The heating uniformity for microwave was improved effectively by the combined drying. The application of the mode stirrers and multi-magnetron radiation modes further improved the microwave heating uniformity. Midilli model can well describe moisture content of paper towel over time. [ABSTRACT FROM AUTHOR]

The reuse of waste papers by conversion into valuable carbon materials has received considerable attention for diverse applications such as energy storage and water purification. However, traditional methods for converting waste papers into materials with suitable properties for specific applications are often complex and ineffective, involving consecutive carbonization and activation steps. Herein, we propose a simple one-step microwave (MW)-assisted synthesis for preparing waste paper-derived porous carbons (WPCs) for energy storage and water purification. Through a 30-min synthesis, WPCs with graphitic structure and high specific surface area were successfully produced. The fabricated WPCs exhibited outstanding charge storage capability with a maximum specific capacitance of 237.7 F g−1. Additionally, the WPC demonstrates a high removal efficiency for various dyes, achieving a maximum removal efficiency of 95.0% for methylene blue. The developed one-step MW synthesis not only enables the production of porous carbon from waste paper, but also offers a viable approach to address solid waste management challenges while simultaneously yielding valuable materials. [Display omitted] • Waste paper-derived porous carbons were synthesized by one-step microwave synthesis. • Within 30-min MW synthesis, graphitic and high-surface area WPCs were produced. • WPC exhibits outstanding electrochemical capacitance of 237.7 F g−1. • WPC exhibits high removal of various dyes, with maximum of 95.0% for methylene blue. [ABSTRACT FROM AUTHOR]

In the manuscripts dealing with thermoanalytical kinetics, many flaws, mistakes, and misconceptions are encountered repeatedly. In this paper, frequent flaws encountered in manuscript of kinetic papers are reviewed, mainly those originating in the false interpretation of the general rate equation, improper employment of integral isoconversional methods, conclusions drawn from the values of a single kinetic parameter, absence of error estimation and application of single-heating rate methods. Assessment of the quality of kinetic treatment is also noticed. Some experimental imperfections that could lead to incorrect values of kinetic parameters are mentioned. [ABSTRACT FROM AUTHOR]

This work investigates which acid can mainly lead to the reduction of alcohols contents in insulating oil during transformer oil-paper insulation aging. In terms of the activation free energy barrier theory, the microscopic mechanisms for the preferential reactions of methanol and ethanol with formic, acetic, naphthenic and stearic acids are analyzed. It is revealed that the decrease in alcohols concentrations in the middle and late stages of transformer oil-paper insulation aging is mainly caused by the reaction between alcohols and naphthenic acid. The results are cross-validated by utilizing the frontier molecular orbital theory and accelerated thermal aging experiments. Additionally, it is observed that methanol is more susceptible to the effect of acids than ethanol in the middle and late stages of aging. The obtained conclusions, in this paper, could provide a theoretical basis for using alcohols in oil as aging indicators to characterize the full-stage aging status of transformer paper insulation. [ABSTRACT FROM AUTHOR]

Highlights • Mechanical properties of waste papers are closely correlated with devolatilization. • Start of devolatilization caused a sudden decrease in relative storage modulus ( E ′ r). • Kinetics of storage modulus change is investigated referring to activation energy. • E ′ r can be predicted with mass loss ratio and CO 2 emission. Abstract This article details a correlation study on early devolatilization behaviors (drying & volatile emission at 25–240 °C) and the change in mechanical properties (expressed by viscoelasticity) of four types of waste papers. The early stage of devolatilization was investigated using the TG-FTIR and mechanical properties using the dynamic mechanical analysis (DMA) method. The results show that the elastic and viscous mechanical properties showed obvious correlations with free and bound water evaporation and volatile emission. The storage modulus (E ′) and loss modulus (E ″) of the papers decreased as temperature increased and at the two important temperatures, namely 100 °C, the start of bound water evaporation, and 150 °C, the start of devolatilization in TG & DTG curves, E ′ showed extrema. Especially the relative storage modulus ( E ′ r) exhibited a sudden decrease at around 150 °C, where the activation energy of thermochemical conversion jumps from low values to high values, indicating the start of devolatilization. CO 2 is the major compound of the volatiles and it is well correlated with E ′ r in exponential function model and can be used as an index for predicting the E ′ r of the waste papers in their early devolatilization stage; while during the drying stage, mass loss ratio can be used to predict E ′ r of the waste papers. [ABSTRACT FROM AUTHOR]

In this research, we characterized and discriminated 24 different kinds of writing/printing papers that may or may not have similar compositions by using Thermogravimetric Analysis (TGA). All paper samples were obtained from the local market in and around Chandigarh (Northwest India). Large differences were observed in the estimation of the kinetic parameters of cellulose and hemicellulose. The calculated percentage weight loss and activation energy for Reaction I and II was further used to determine the thermal stability of each sample. Although few differences were observed on visual examination of the samples, significant differences were obtained on the basis of their kinetic parameters. Multivariate analysis was further applied to the results and considerable enhancement of the results was observed. The current study provides 99.28% discrimination among all the possible pairs of paper samples. The technique is cost-effective, involves no sample preparation, consumes less time and provides reproducible results. [ABSTRACT FROM AUTHOR]

Cellulose material is a dielectric with intricate microscopic relaxation processes due to its complex structure. However, conventional models and curve fitting methods used for tracing and analyzing these processes often fail to capture crucial dielectric information. This paper aimed to extract the Distribution of Relaxation Time (DRT), the most fundamental and effective dielectric information providing the time scale and relative contribution of all microscopic relaxation processes. First, a distributed extended Debye model with infinite branches was constructed based on the microscopic nature of dielectric relaxation. Then, an implicit equation of the DRT function was established, inspired by the mathematical principles of infinite subdivision and summation. To obtain the numeral solution of the DRT function, a regularization method was proposed and validated. Finally, the approach was applied to cellulose insulating paper with varying degradation degrees. The relaxation process with a long time constant played a significant role, and variations during the degradation process were attributed to reduced activation energy. With clear physical interpretation and robust mathematical foundation, our method sheds light on the intricate dielectric relaxation processes in cellulose. This not only enhances the theoretical understanding and practical application of cellulose materials but also provides valuable insights for the analysis and application of other materials. [Display omitted] [ABSTRACT FROM AUTHOR]

• A simple and fast method for loading electrocatalyst Ni 2 B on carbon paper. • A simple process that provides ideas for industrial production. • The solution resistance (Rsol) is only 2.68 Ω after electrochemical impedance testing on Ni 2 B/cp. • The mass of catalyst loaded is only (2–2.5) mg per cm2. In this paper, nickel boride (Ni 2 B) was successfully loaded on carbon fiber paper by electrodeposition and high temperature annealing. The activities of the electrode materials were compared at different deposition currents. The results show that the Ni 2 B/CP-2 electrode with a high surface crystallinity and tetrahedral structure exhibits excellent (OER) activity. Specifically, it can drive a current density of 10 mA cm−2 at a low overpotential of 280.4 mV in 1 M KOH solution, and it has the highest TOF value among these four materials. Furthermore, highly electronegative boron reduces the energy barrier of the nickel metal oxidation reaction and contributes to the charge transfer. [ABSTRACT FROM AUTHOR]

Direct observation of the capture cross section is challenging due to the need for extremely short filling pulses in the two-gate Deep-Level Transient Spectroscopy (DLTS). Simple estimation of the cross section can be done from DLTS and admittance spectroscopy data but it is not feasible to distinguish temperature dependence of pre-exponential and exponential parts of the emission rate equation with sufficient precision conducting a single experiment. This paper presents experimental data of deep levels in β-Ga2O3 that has been gathered by our group since 2017. Based on the gathered data, we propose a derivation of apparent activation energy (E a m) and capture cross section (σ n m) assuming the temperature dependent capture via the multiphonon emission model, which resulted in a strong correlation between E a m and σ n m according to the Meyer–Neldel rule, which allowed us to estimate low- and high-temperature capture coefficients C 0 and C 1 as well as capture barrier E b. It also has been shown that without considering the temperature dependence of capture cross section, the experimental values of σ n are overestimated by 1–3 orders of magnitude. A careful consideration of the data also allows to be more certain identifying deep levels by their "fingerprints" (E a and σ n) considering two additional parameters (E M N and σ 00) and to verify the density functional theory computation of deep-level recombination properties. [ABSTRACT FROM AUTHOR]

It is significant to investigate the calcium carbonate (CaCO3) precipitation mechanism during the carbon capture process; nevertheless, CaCO3 precipitation is not clearly understood yet. Understanding the carbonation mechanism at the atomic level can contribute to the mineralization capture and utilization of carbon dioxide, as well as the development of new cementitious materials with high-performance. There are many factors, such as temperature and CO2 concentration, that can influence the carbonation reaction. In order to achieve better carbonation efficiency, the reaction conditions of carbonation should be fully verified. Therefore, based on molecular dynamics simulations, this paper investigates the atomic-scale mechanism of carbonation. We investigate the effect of carbonation factors, including temperature and concentration, on the kinetics of carbonation (polymerization rate and activation energy), the early nucleation of calcium carbonate, etc. Then, we analyze the local stresses of atoms to reveal the driving force of early stage carbonate nucleation and the reasons for the evolution of polymerization rate and activation energy. Results show that the higher the calcium concentration or temperature, the higher the polymerization rate of calcium carbonate. In addition, the activation energies of the carbonation reaction increase with the decrease in calcium concentrations. [ABSTRACT FROM AUTHOR]

As one of the promising room temperature nuclear radiation detection materials, the all-inorganic perovskite CsPbBr3 single crystal has been receiving much attention in recent years. Even though the performance of the CsPbBr3 detector is improving continuously, the disadvantages of detection instability have not been solved fundamentally, and this instability is mainly caused by ionic migration in the CsPbBr3 single crystal itself. In this paper, a reasonable ionic migration model is proposed based on an in-depth study of the current hysteresis phenomenon and ionic migration mechanism in the Ti/CsPbBr3/Ti detector. The model shows that the ions migrate to the anode or cathode under an external electric field, and the accumulated ions subsequently form an inverted internal electric field inside the crystal and carrier transport barriers at the metal–semiconductor interface simultaneously. The photoelectric characteristic and ionic migration activation energy (E a i o n) fitting results also prove the rationality of the ionic migration model. Furthermore, the ionic migration model can also be used to explain the left-shift of the energy response peak and the decrease in the normalized charge collection efficiency in the Ti/CsPbBr3/Ti detector. This paper systematically investigates the intrinsic origin of migrated ions and the influence of ionic migration on detection stability, which will provide a potential solution to improve detection stability by suppressing ionic migration in the near future. [ABSTRACT FROM AUTHOR]

The pyrolysis of waste disposable paper cups (WDPCs) was investigated using a thermogravimetric analyser coupled with a Fourier transform infrared spectrometer. The activation energies of the pyrolysis reactions were obtained by the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods respectively. The kinetic model was determined by the master plots method. Thermogravimetric results showed that the highest weight loss rate occurred from 345 to 365 °C as the heating rate was increased from 10 to 30 °C min-1, indicating the pyrolysis of cellulosic material in the WDPC. The weight loss between 400 and 500 °C can be attributed to the decomposition of polyethylene. By analysing the FTIR spectra, it was found that the absorbance of all the evolved gaseous products had peaks at 360 °C due to the decomposition of cellulose fibres and the cracking of polyethylene at 485 °C led to the emergence of a second hydrocarbon peak. Ketones were the most abundant condensable organic products and CO2 was the dominating gaseous product, which can also be produced via secondary cracking of the small molecule organics above 400 °C. Kinetic analysis revealed that the average activation energy of the pyrolysis of the WDPC was 153.75 kJ mol-1 from the FWO method and 151.43 kJ mol-1 from the KAS method. The reaction mechanism can be described by the R3 model. [ABSTRACT FROM AUTHOR]

Pyrolysis characteristics of Tetra Pak, a paperboard-polyethylene-aluminium foil, were investigated in this study with a focus on the synergistic effect between its individual components. Scanning electron microscopy analysis indicated that molten LDPE coating on cellulose surface led to suppression on mass and heat transfer and the increased activation energy of pyrolysis reaction. Samples of individual components and simulated Tetra Pak packaging were pyrolyzed in a thermogravimetric analyzer at various heating rates. Synergistic effect between cellulose and LDPE on E a and the formation of characteristic products are investigated: Kinetic analysis showed that the cellulose decomposition peak in the simulated mixture exhibited a higher E a than that of pure cellulose at each conversion rate. For LDPE, the free radicals formed from cellulose pyrolysis enhanced the degradation of plastic polymers, resulting that E a of its decomposition peak in the mixture being lower in comparison to pure LDPE, with a discrepancy of around 16–27 kJ·mol−1. The formation of characteristic products including levoglucosan, furfural, 5-hydroxymethylfurfural, and alkanes from pyrolysis of cellulose and LDPE mixture with different mass ratios was further investigated in a micro-pyrolyzer. The results suggested that synergistic effects and physical barrier existed during fast pyrolysis between cellulose and LDPE. The extent of the synergy effect depended on the proportion of cellulose and LDPE in the mixture. • Synergistic effect was investigated during pyrolysis of Tetra Pak. • Molten LDPE coating on cellulose increases E a of cellulose pyrolysis. • The extent of synergy effect depends on the proportion of cellulose and LDPE. [ABSTRACT FROM AUTHOR]

Activation energy is popularly used for the estimation of remaining life of transformer insulation. It is defined as the average rate of all reactions that happen with cellulose. Existing literature shows that the activation energy of oil–paper insulation can be obtained from polarization depolarization current (PDC) and return voltage measurement (RVM) data that are measured at a specific temperature. It is practically difficult to ensure the same measurement temperature for both PDC and RVM data. On the other hand, PDC data and its analysis get influenced by de-trapping current. This de-trapping current is generated by ionic charge carriers that get freed from trap sites during PDC measurement process. Formation of these trap sites is related to physical, chemical reactions that happen at oil–paper interface. This paper proposes a methodology which uses de-trapped charge, dislodged from deep and shallow traps, to assess insulation condition and for the prediction of activation energy. Thus, eliminating the need of RVM data. The proposed method is tested using data collected from various real-life in-service transformers. [ABSTRACT FROM AUTHOR]

The oxygen-rich vacancies and crystalline/amorphous Ru doping CoCu+Ru 10 -LDH/NF were successfully synthesized using MOF as precursor and template. The combination of heteroatom doping, interface engineering, and defect engineering can significantly improve the conductivity, intrinsic activity, and active site utilization of the catalyst to achieve efficient OER performance. This design concept presented in this paper provides a new way to develop high performance OER electrocatalysts. [Display omitted] Reinforcing the development of efficient and robust electrocatalysts is pivotal in addressing the challenges associated with oxygen evolution reactions (OER) in water splitting technology. Here, an amorphous/crystalline low-ruthenium-doped bimetallic layered double hydroxide (LDH) electrocatalyst (a/c-CoCu + Ru x -LDH/NF) with massive oxygen vacancy on nickel foam was fabricated via ion-exchange and chemical etching, facilitating efficient OER. Among the various catalyst materials tested, the a/c-CoCu + Ru 10 -LDH/NF exhibits remarkable performance in the OER when employed in an alkaline electrolyte containing 1 M KOH. Achieving a minimal overpotential at 10 mA cm−2 of 214 mV, exhibiting a low Tafel slope value of 64.3 mV dec−1 and exceptional durability lasting for over 100 h. Theoretical calculations demonstrate that the electron structure and d-band center of CoCu-LDH can be effectively regulated through the utilization of a strategy possessing abundant oxygen vacancies and a Ru-doped crystalline/amorphous heterostructure. It will lead to optimized adsorption free energy of reactants and reduced energy barriers for OER. The construction strategy proposed in this paper for catalysts with amorphous/crystalline heterointerfaces offer a novel opportunity to achieve highly efficient OER. [ABSTRACT FROM AUTHOR]

The sodium aluminosilicate (NAS) glass family is important for many different industrial applications, but glass relaxation has not yet been thoroughly studied in this system. Thermal analysis techniques such as differential scanning calorimetry (DSC) and modulated differential scanning calorimetry (MDSC) can provide insight into the enthalpy relaxation of glass by measuring the glass transition temperature (Tg), activation energy, and enthalpy of relaxation. MDSC is mostly used to study nonoxide and low Tg glasses, and there is much debate about whether the nonreversing heat flow analysis method is accurate. To the authors’ knowledge, this is the first paper using MDSC to study these NAS compositions, and one of few papers to report MDSC on high Tg oxide glasses. We report on one set of modulation conditions that obtain a linear response using Lissajous curves, as well as comparing the activation energy calculated from DSC with the enthalpy of relaxation obtained from MDSC. Our results show that the activation energy and enthalpy of relaxation do not give the same compositional minimum in relaxation, and therefore more work is needed to investigate the validity of the nonreversing heat flow approach for high Tg oxide glasses. [ABSTRACT FROM AUTHOR]

In this paper, the non-isothermal co-pyrolysis of walnut shell (WS), Enteromorpha clathrata (EN), and their blends (WEB) was studied using a thermogravimetric analyzer (TGA). For all the samples, three different decomposition stages were identified by the thermogravimetric analysis. At the same temperature, the mass loss of WEB was always stable between the values of WS and EN. In addition, different heating rates resulted in different TG–DTG profiles. The interaction between WS and EN showed a gradual enhancement with temperature increase, and the most significant interaction was generated when the blending proportion of WS and EN was 7:3. The Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and masterplots methods were used to determine the kinetic triplets. The results show that for different blending ratios, the effective activation energies of WS and EN co-pyrolysis vary from 86.21 to 247.86 kJ mol−1 when the conversion rate is 0.2–0.8. The most appropriate mechanism for the pyrolysis of 70WS30EN is g(α)=[-ln(1-α)]1/2 with kinetic parameters: apparent activation energy 86.21 kJ mol-1 and pre-exponential factor 8.99 × 1016 s−1. The findings in this paper provide a reference for further research on the co-pyrolysis of aquatic and terrestrial biomass. [ABSTRACT FROM AUTHOR]

The undesired ignition of ammunitions during their different stages of life can lead to hazardous situations for goods and people. To tackle these potential issues, low-vulnerability ammunitions (LOVA) have been developed. However, this loss of sensitivity can lead to ignition issues. Therefore, the study of ignition phenomena like thermal decomposition is essential. This paper is about the thermal decomposition of three LOVA gun propellants based on RDX and nitrocellulose. Decomposition is studied by thermogravimetric analysis (TGA) between 303 and 573 K, under argon atmosphere and five heating rates (0.3, 0.5, 0.8, 1.0, 1.2 K min−1). A kinetic analysis method, considering ICTAC recommendations, is developed in this paper and applied to TG results. The latter allows to determine global kinetic parameters (pre-exponential factor, activation energy and reaction model based on the truncated Šesták-Berggren equation) to obtain a decomposition law depending on temperature and extent of conversion. Models with three independent parallel kinetic steps are obtained. Their integration provides mass loss curves in good agreement with the TG results. [ABSTRACT FROM AUTHOR]

Municipal papers and polyethylene terephthalate (PET) wastes are primary constituents of municipal solid waste (MSW) which necessitates effective disposal. Co-pyrolysis is an efficient transformation technology for the production of valuable gas and liquid fuels. Therefore, co-pyrolysis characteristics, kinetics, gas and liquid products of cellulose and PET mixtures were investigated in a two-stage reactor by multiple characterizations coupling with deep learning approach. The results indicated that there exhibited positive interaction for cellulose and PET co-pyrolysis in terms of mass difference (δ m) and mass loss rate difference (δ r) between experimental and calculated values. The thermal decomposition process and synergistic effects (δ m and δ r) were accurately predicted by deep learning approaches (R 2 =0.9823–0.9993) using temperature, catalyst, mixing ratio and heating rate variables. Feature importance revealed that the temperature, catalyst, heating rate and mixing ratio were in the descending order to affect the remaining mass from TG curves. And the temperature played a predominant role in synergistic effects. The Flynn-Wall-Ozawa (FWO) method was more suitable for fitting the pyrolysis process to obtain activation energy (E a) with higher R 2 (0.94714–0.99640) compared with Kissinger-Akahira-Sunose (KAS) method. When the mixing ratio of cellulose and PET was 1:1, the E a was significantly reduced to 80.73 KJ/mol, and further reduced to 73.04 KJ/mol by introducing the catalyst, as compared to E a of individual cellulose (178.95 KJ/mol) and PET (198.34 KJ/mol). Co-pyrolysis of cellulose and PET led to a reduction of carbohydrates, furans, alcohols, ketones, and phenols, while the content of acids was remarkably increased which was consistent with the observation in FTIR that the absorption peak of C＝O became sharp and strong. The introduction of ZSM-11 resulted in an increase in aromatics and a decrease in acids content owing to aromatization and deoxygenation. This work is expected to offer beneficial guidance for the efficient disposal of MSW and the application of deep learning methods. [Display omitted] • The interactive pathway for catalytic co-pyrolysis of cellulose and PET was proposed. • The activation energy reached the lowest 73.04 KJ/mol when the mixing ratio was 1:1. • Optimized convolutional neural network predicted synergistic effects with R 2 > 0.99. • Feature importance for TG was temperature > catalyst > heating rate > mixing ratio. [ABSTRACT FROM AUTHOR]

• Kinetics of paper-laminated phenolic PCB pyrolysis was explored based on the TGA results. • The kinetic parameters were estimated by isoconversional model-free kinetic approaches. • Variation of apparent activation energy indicated the mechanism change during the pyrolysis. • Discrete and gaussian DAEMs were implemented to describe the kinetics of pyrolysis process. • Good agreement was observed between experimental results and data predicted by the DAEMs. This work explores the pyrolysis characteristics and kinetic behavior of paper-laminated phenolic printed circuit boards (PLP-PCBs) using thermogravimetric analysis under non-isothermal linear heating programs. The initial estimation of the kinetic parameters during the pyrolysis was obtained from the analysis of the experimental data by three isoconversional kinetic models, i.e. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) integral methods, as well as the Friedman differential method. For all three methods, the apparent activation energy exhibited a strong dependence on the degree of the reaction conversion. To allow for the complexity of the reactions involved in the PLP-PCB pyrolysis, two distributed activation energy models (DAEMs) with a first-order reaction function were derived by assuming the discrete and multi-Gaussian distributions for the activation energies. A six pseudo-component Gaussian DAEM was able to accurately describe the PLP-PCB pyrolysis. By applying the discrete DAEM algorithm, the pyrolysis of PLP-PCB could be precisely characterized by 37 dominating reactions. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, an analysis of co-pyrolysis municipal solid waste and paper sludge with additive (MgO) were investigated by TG-FTIR and Py-GC/MS. The proportions of paper sludge in the blends were 10%, 30% and 50%, respectively. The pyrolysis characteristics, the yields of pollutants (CO, SO 2 , NO, HCl) and CO 2 , the products and chemical composition, the kinetic behaviors and the distribution activation energy model were investigated. After adding paper sludge, the sums of pollutants reduced, the amount of aliphatic hydrocarbons decreased and oxygenates compounds increased. After adding MgO, the results showed that the residue mass decreased, the emission of pollutants reduced, the ratio of aliphatic hydrocarbons became larger, the ratio of oxygenates compounds became smaller, and the activation energy reduced. According to the beforementioned results, the 30% percentage of paper sludge in the mixture with MgO might be the most suitable ratio for co-pyrolysis. [ABSTRACT FROM AUTHOR]

In a recent paper, Becke et al. [J. Chem. Phys. 158, 151103 (2023)] presented a novel double hybrid density functional, "DH23," whose terms are based on good physics. Its 12 coefficients were trained on the GMTKN55 (general main-group thermochemistry, kinetics, and noncovalent interactions) chemical database of Goerigk et al. [Phys. Chem. Chem. Phys. 19, 32184 (2017)]. The lowest GMTKN55 "WTMAD2" error to date for any hybrid or double hybrid density functional was obtained (1.76 kcal/mol). Here, we make some revisions to DH23 and test its efficacy on reference data beyond GMTKN55, namely, organometallic reaction energies and barrier heights. The results confirm that DH23 is robust outside its training set. In the process, a slightly smaller GMTKN55 WTMAD2 of 1.73 kcal/mol is achieved. [ABSTRACT FROM AUTHOR]

Mechanical strength of insulation paper was the key factor for the life of large oil-immersed transformer. To more accurately assess the life of the insulation paper, the aging mechanisms of transformer insulation paper were analysed and a new method using the activation energy was proposed to access the paper's life. Then the life prediction model was defined. Accelerated aging tests of transformer oil-paper insulation samples were executed under different temperatures. According to the test results, the parameters of life prediction model were found out. So, the life of insulation paper under the working condition could be calculated. In the end, an example of insulation paper life evaluation was given to illustrate the effectiveness of this method. [ABSTRACT FROM AUTHOR]

Although degradation of iron gall ink containing paper has been scientifically studied for almost 250 years, we still do not have a good understanding of the kinetics of the process. While many studies focussed on model samples to avoid the inhomogeneity of real historic samples or the need for sampling, this research was conducted on a selection of real documents. Accelerated degradation experiments were performed at six combinations of temperature and relative humidity (RH) in the intervals 50–80 °C/20–80% RH. The analytical methods were optimised such that sample consumption was minimised and errors and uncertainties were evaluated. The results show that the rate of degradation, measured as change in the degree of polymerisation of cellulose in paper beneath ink, can be described in Arrhenius terms, and that the apparent activation energy for the process depends on the moisture content in the material. The variation is consistent with the process of hydrolysis becoming less prominent at lower moisture content values, although the results indicate that hydrolytic degradation predominates during natural ink-induced degradation. In the context of the historic samples used in the study, the presence of ink accelerated the degradation of paper by a constant factor of 1.59 in comparison to paper without ink, across the range of experimental T and RH. This indicates that a dose-response function could be developed for ink-induced degradation of paper. [ABSTRACT FROM AUTHOR]

The correct form is 5 HT ht Graph Fourth error (serious) The equation (21) in [[1]] is as follows 6 HT ht Graph Equation (6) is a dimensionless equation presented in [[1]] after the non-dimensionalization in equation (17) in [[1]]. [Extracted from the article]

[Display omitted] • Compared to N 2 , the pyrolysis of MSW and PS was more complete under CO 2 atmosphere. • The evolution of six typical pyrolysis products were illustrated by TG-FTIR. • MgO could act as a catalyst to promote the pyrolysis reaction of blends. • Through DAEM, the activation energy in two stages were about 170 and 300 kJ/mol. In order to explore a harmless and resource-based way to treat municipal solid waste (MSW) and paper sludge (PS), the co-pyrolysis MSW and PS was studied in this paper. Firstly, MSW and PS had the lower residue mass, and MSW had higher pyrolysis index under CO 2 atmosphere, compared with the one under N 2 atmosphere. Hence, the CO 2 was used as the carrier gas in the following study. Secondly, under CO 2 atmosphere, the co-pyrolysis of MSW and PS with and without MgO were researched. With the increasing of PS ratio, the pyrolysis performance of the blends decreased constantly. MgO act as catalyst could improve the pyrolysis characteristic index of the blends. However, MgO was an inorganic salt and it would affect the synergistic effect of MSW and PS. The curves of online evolutions of all the gas products and the functional groups had an obvious peak at around 500 ℃. The activation energy of the blends in the first step (<600 ℃) were around 170 kJ/mol and reached more than 300 kJ/mol of the second step (600−1000 ℃). In addition, the adding of MgO could decrease the activation energy of MSW, 50M50P and PS. Finally, 50M50P-M was suitable for treating more sludge. And these results could offer some referential information for designing and optimizing the co-pyrolysis technology for MSW and PS. [ABSTRACT FROM AUTHOR]

The effectiveness of element doping in enhancing the hydrogen storage performance of ZrCo alloys has been well established. However, the impact of single element doping is limited, and research on the synergistic effect of multi-element alloying remains relatively scarce. In this paper, the hydrogen storage properties of Zr 0·75 Ti 0·125 Nb 0·125 Co 0·75 Ni 0.25 (ZTNCN) alloy were investigated using the first-principles method to explore the synergistic effect of Ti, Nb and Ni doping on ZrCo. The results indicate that the (−110) surface of ZTNCN undergoes significant reconstruction, leading to enhanced adsorption and dissociation of hydrogen on the surface. Moreover, there is no apparent dissociation barrier for H 2 , facilitating easier migration of H on the surface. The difference in atomic size leads to a variation in lattice interstices, resulting in a lower diffusion energy barrier for H compared to that of the ZrCoH x system. Through atomic substitution, the space within the 8e site becomes compressed, which makes the alloy exhibit improved resistance against disproportionation. Therefore, the synergistic effect of Ti, Nb, and Ni can greatly enhance hydrogen absorption and desorption kinetics in alloys and improve anti-disproportionation. [Display omitted] • The co-doping of Ti, Nb, and Ni promotes remodeling of the surface, enhancing hydrogen storage. • The co-doping of Ti, Nb, and Ni enhances H 2 dissociation and promotes H migration and diffusion. • The release of hydrogen from ZTNCN hydride is easier than from ZrCoH x system. • The co-doping of Ti, Nb, and Ni improves the ZrCo alloy's anti-disproportionation. [ABSTRACT FROM AUTHOR]

This paper analyzes the heat transport phenomena of two-phase nanofluid within a permeable circular segment with an interaction of Arrhenius activation energy and, examines the interaction of convective boundary conditions affecting the flow characteristics. The pre-exponential factor of the Arrhenius equation deals with the collision between molecules, and it has significant applications for getting the rate of a chemical reaction and is used to estimate material properties with changes in temperature and energy. To a greater extent, the external uniform heat source encourages thermal properties on account of the behavior of Brownian and thermophoresis parameters. The transformation of the standard nondimensional form of the governing equations is obtained for the assumption of appropriate similarity variables and stream function. The set of these transformed equations is tackled numerically with the shooting technique. The characteristics of physical parameters on the flow phenomena are presented graphically and the validation with earlier research displays a strong correlation for the specific case. The special attraction of the present investigation is the regression analysis for the simulated results of heat and solutal transfer rates using Response Surface Methodology considering various characterizing parameters like heat source, thermal radiation, curvature, activation energy, thermal and solutal Biot numbers within certain range. [ABSTRACT FROM AUTHOR]

In recent days, entropy generation has attracted the attention of several researchers due to its applications in manufacturing electronic devices, heat exchangers, conservation of energy, and generation of power. Further, activation energy is an essential requirement in automobile and chemical industries, nuclear reactors, and so on. This paper investigation aims to examine the entropy generation and the mass and energy transfer in the magneto-hydro dynamic movement of convective Carreau-Yasuda nano liquid past a porous stretching sheet with the consequences of activation energy, energy source, and binary chemical reaction. Also, the analysis of the impact of viscous and Joule dissipation in the presence of suction/injection into the Buongiorno model is an essential objective of this study. By introducing a similarity variable, the partial differential equations are altered into a system of ordinary differential equations. Numerical solutions to the modified equations are determined by utilizing a BVP5C MATLAB package. The findings are presented visually for several relevant flow characteristics and explained carefully. The thermophoresis parameter and activation energy parameter optimize the concentration of nanoparticles. These outcomes further indicate that as the larger Brinkmann and permeability parameters the entropy generation is broadened. It is discovered that an augmentation in thermal and solutal Grashof numbers is associated with greater velocity distribution. [ABSTRACT FROM AUTHOR]

Exploring Earth-abundant and efficient electrocatalysts to replace Ir and Ru for the acidic oxygen evolution reaction (OER) is essential to reduce the cost of clean hydrogen production. Here, we show that trace amounts of electronegative non-metallic element fluorine (F)-doped Co3O4 nanoneedles improve the activity and stability of Co3O4. The F-doped Co3O4 nanoneedles supported on carbon paper (F-Co3O4/CP) exhibit an overpotential of 350 mV at 10 mA cm-2 for the acidic OER. In addition, their performance remains consistent after continuous operation for 80 h. Detailed investigations reveal that introducing an anion promotes the enrichment of OH on the surface of Co3O4 and prevents acid corrosion, thereby enhancing the intrinsic OER activity and stability. Theoretical calculations further indicate that F doping can effectively improve electron transfer and optimize the energy barrier for the formation of *OOH intermediates, which significantly improves OER performance. This study provides guidance for designing efficient and stable non-noble metal acidic water oxidation catalysts. [ABSTRACT FROM AUTHOR]

This paper studied the minimum ignition temperature of the dust layer (MITL) of oil-immersed coal and the heat effect and apparent activation energy (Ea) of raw coal and oil-immersed coal. Based upon the results, the addition of crude oil to coal could reduce the MITL, ameliorate the ignition sensitivity, and increase the heat effect of coal dust. The average Ea of oil-immersed coal was lower than that of raw coal. When there was a 10.8 mass% oil-immersed concentration of oil-immersed coal with the most acceptable particle size (≤ 75 μm), the MITL was 24.24% lower than that of raw coal. Furthermore, the exothermic value of oil-immersed coal was 26.67% higher than that of raw coal. Besides, the average Ea of oil-immersed coal was 26.8% lower than that of raw coal. The research herein is expected to improve people's understanding of the thermal hazard characteristics of oil-immersed coal dust, reduce the risk of coal dust fires and explosions, and ensure production safety. [ABSTRACT FROM AUTHOR]

This paper examines the activation energy influence in third-grade nanoparticle flow model (TG-NPFM), which is nonlinear mixed convective flow over a spinning disk under the influence of heat sink/source as well as viscous dissipation by utilizing Bayesian Regulation Method with backpropagated Artificial Neural Networks (BRM-BPANN). Nonlinear thermal radiation is also involved in the considered flow dynamics to obtain the approximated numerical solutions. The nonlinear PDEs of TG-NPFM are then transformed into nonlinear ODEs by implementing the corresponding transformation. We solved these ODEs by Optimal Homotopy Analysis Method (OHAM) to explain the dataset used as a reference for BRM-BPANN for different scenarios of TG-NPFM. This reference dataset is then exported to MATLAB to compute the results. The outcomes of TG-NPFM are figured by adopting the procedures of testing, validation and training. Moreover, approximated solution is compared with standard solution and the efficacy examination of TG-NPFM is authenticated by the studies of MSE, error histogram and regression plots. These soft computation frameworks provide incentive to use an efficient and dependable alternative paradigm built on soft computing environments to solve problems by doing a descriptive analysis to mitigate the impacts of different physical features. It is a new implementation of intelligent computational system of artificial intelligence introduced by incorporating the solver BRM-BPANN for interpreting the TG-NPFM. The absolute error values lie between 10 − 8 to 10 − 5 , 10 − 1 0 to 10 − 5 , 10 − 8 to 10 − 4 , 10 − 9 to 10 − 3 , 10 − 9 to 10 − 5 , 10 − 9 to 10 − 3 , 10 − 9 to 10 − 3 and 10 − 9 to 10 − 3 , which show the reliability and accuracy of the technique. The convergence and precision of the algorithm can easily be seen through the results of performance, training state and fitness plot, along with the regression value of R = 1. [ABSTRACT FROM AUTHOR]

This paper investigates the esterase activity of minimalist amyloid fibers composed of short seven‐residue peptides, IHIHIHI (IH7) and IHIHIQI (IH7Q), with a particular focus on the role of the sixth residue position within the peptide sequence. Through computational simulations and analyses, we explore the molecular mechanisms underlying catalysis in these amyloid‐based enzymes. Contrary to initial hypotheses, our study reveals that the twist angle of the fiber, and thus the catalytic site's environment, is not notably affected by the sixth residue. Instead, the sixth residue interacts with the p‐nitrophenylacetate (pNPA) substrate, particularly through its −NO2 group, potentially enhancing catalysis. Quantum mechanics/molecular mechanics (QM/MM) simulations of the reaction mechanism suggest that the polarizing effect of glutamine enhances catalytic activity by forming a stabilizing network of hydrogen bonds with pNPA, leading to lower energy barriers and a more exergonic reaction. Our findings provide valuable insights into the intricate interplay between peptide sequence, structural arrangement, and catalytic function in amyloid‐based enzymes, offering potentially valuable information for the design and optimization of biomimetic catalysts. [ABSTRACT FROM AUTHOR]

In order to study the use of drying models in vacuum-infrared drying, an experiment was conducted to investigate the drying process of cherry pips at different temperatures of 60°C, 70°C and 80°C, drying characteristic curves were constructed and analysed using 6 types of thin layers, and effective diffusion coefficients, moisture content and activation energy were calculated. The results showed that the drying temperature has a greater influence on the drying rate of cherry pits, and the drying time decreases with increasing drying temperature. The main drying step occurs in the downward drying stage. Comparison of the fitting results of the six thin layer drying models presented in this paper showed that Wang and Singh's model fits better for cherry pips (${{\rm{R}}^2} \gt 0,9996$ R 2 > 0 , 9996) and the predicted values of the model agree well with the experimental values. These values are suitable for describing the drying characteristics of cherry pips under any conditions. T. [ABSTRACT FROM AUTHOR]

The preparation of spherical TATB is a key and challenging research focus in the field of energetic materials. In this paper, microspherical TATB was successfully prepared by the oil-in-oil emulsion method with DMSO and BMIM as solvents for the first time. The optimal process conditions for oil-in-oil emulsions were obtained, and the morphology, structure, particle size distribution, specific surface area, and thermal decomposition performance of the spherical TATB were characterized. The results showed that the optimal process conditions for emulsion stability were as follows: the ratio of continuous to discontinuous phases was 5/5, Tween-80 was used as the surfactant, and the dosage of the TATB raw material was 1%, which could form a stable emulsion. The crystal structure of the TATB samples prepared from the stable emulsion did not change, but only the morphology was changed. The prepared TATB was microspherical with a particle size distribution D50 of 17.5 μm, and the specific surface area was 1.639 m2 g−1. Compared with TATB, spherical TATB exhibited a unique nanostructure on its surface, which caused its thermal decomposition exothermic peak to advance by 8.5 °C and activation energy to decrease by 82.71 kJ mol−1. This method is expected to provide new insights into the spherization of other insoluble explosives. [ABSTRACT FROM AUTHOR]

NH3 is a highly promising zero‐carbon fuel. In this paper, 19 important reactions involving NH3, NH2, and NH in the ammonia system are studied to better establish the combustion reaction mechanism of ammonia. These reactions encompass the reactions of NH3, NH2, and NH with free radicals and inorganic compounds such as O, H, OH, NO, H2O, and O2. Utilizing the transition state theory and Yao‐Lin method, energy barrier diagrams for these reactions are presented, and the harmonic and anharmonic rate constants are calculated over the temperature range from 300 to 4000 K. The calculation results reveal that, in most reactions, the harmonic rate constants exceed the anharmonic rate constants and the experimental results are closer to the anharmonic rate constants. Additionally, the kinetic and thermodynamic parameters are fitted. To summarize, most reactions are significantly influenced by the anharmonic effect. [ABSTRACT FROM AUTHOR]

Hybrid nanofluids have caught the attention of scholars and investigators in the present technological period due to their improved thermophysical features and the desire to boost heat transfer rates compared to those of conventional fluids. The present paper is mainly concerned with heat transmission in cone-disk geometry in the presence of a magnetic field, activation energy, and non-uniform heat absorption/generation. In this work, the cone-disk (CD) apparatus is considered to have a rotating cone (RC) and a stretching disk, along with iron oxide and cobalt ferrite-based hybrid nanofluid. Appropriate similarity transformations are employed to change the physically modeled equations into ordinary differential equations (ODEs). Heat transfer rates at both surfaces are estimated by implementing a modified energy equation with non-uniform heat absorption/generation. The outcomes illustrated that the inclusion of such physical streamwise heat conduction variables in the energy equation has a significant impact on the well-known conclusions of heat transfer rates. To understand flow profile behavior, we have resorted to the RKF-45 method and the shooting method, which are illustrated using graphs. The findings provide conclusive evidence that wall stretching alters the flow, heat, and mass profile characteristics within the conical gap. The wall deformation caused by disk stretching was found to have a potential impact of modifying the centripetal/centrifugal flow characteristics of the disk, increasing the flow velocity and swirling angles. A rise in activation energy leads to an improved concentration field. [ABSTRACT FROM AUTHOR]

Reductive elimination is a key step in Ni-catalysed cross-couplings, which is often considered to result in new covalent bonds. Due to the weak oxidizing ability of Ni(II) species, reductive eliminations from Ni(II) centers are challenging. A thorough mechanistic understanding of this process could inspire the rational design of Ni-catalysed coupling reactions. In this article, we give an overview of recent advances in the mechanistic study of reductive elimination from Ni(II) species achieved by our group. Three possible models for reductive elimination from Ni(II) species were investigated and discussed, including direct reductive elimination, electron density-controlled reductive elimination, and oxidation-induced reductive elimination. Notably, the direct reductive elimination from Ni(II) species often requires a high activation energy in some cases. In contrast, the electron density-controlled and oxidation-induced reductive elimination pathways can significantly enhance the driving force for reductive elimination, accelerating the formation of new covalent bonds. The intricate reaction mechanisms for each of these pathways are thoroughly discussed and systematically summarized in this paper. These computational studies showcase the characteristics of three models for reductive elimination from Ni(II) species, and we hope that it will spur the development of mechanistic studies of cross-coupling reactions. [ABSTRACT FROM AUTHOR]

The explosion characteristics of AlH 3 dust clouds with varying micron particle sizes are investigated in this paper. The explosion mechanism of AlH 3 dust clouds is initially explored. The results indicate that the activation energy for hydrogen evolution shows an increasing trend with the AlH 3 particle size, and both of these values are comparable to the 30 kJ/mol desorption energy of hydrogen from large AlH 3 clusters. Due to the rapid dehydrogenation rate and small-size residual aluminum core, fine AlH 3 particles exhibit a continuous gas-phase flame and fast propagation velocity. With increasing particle size, the lower dehydrogenation rate, reduced specific surface area, and higher volume heat capacity contribute to a higher level of incomplete reaction. Consequently, large micro-sized AlH 3 particles display a discrete flame, slower flame velocity, and lower explosion pressure. The flame delamination phenomenon is not observed in our experiments on AlH 3 dust clouds. [Display omitted] • The explosion characteristics of AlH 3 dust with different particle sizes are studied. • The phenomenon of flame delamination is not observed in the AlH 3 dust clouds. • The activation energy for H 2 release increases with particle size, similar to large AlH 3 clusters' desorption energy. • The explosion mechanism of AlH 3 dust with different particle size is revealed. [ABSTRACT FROM AUTHOR]

Fe(III) has been proved to be a more effective oxidant than dissolved oxygen at ambient temperature, however, the role of Fe(III) in pyrite acidic pressure oxidation was rarely discussed so far. In this paper, in-situ electrochemical investigation was performed using a flow-through autoclave system in acidic pressure oxidation environment. The results illustrated that increasing Fe(III) concentrations led to raising in redox potential of the solution, and decreased passivation of pyrite caused by deposition of elemental sulfur. Reduction of Fe(III) at pyrite surface was a fast reaction with low activation energy, it was only slightly promoted by rising temperatures. While, the oxidation rate of pyrite at all investigated Fe(III) concentrations increased obviously with rising temperatures, the anodic reaction was the rate-limiting step in the overall reaction. Activation energy of pyrite oxidation decreased from 47.74 to 28.79 kJ/mol when Fe(III) concentration was increased from 0.05 to 0.50 g/L, showing that the reaction kinetics were limited by the rate of electrochemical reaction at low Fe(III) concentrations, while, it gradually turned to be diffusion control with increasing Fe(III) concentrations. [ABSTRACT FROM AUTHOR]

An expanding sheet problem is more relevant when the thickness of the sheet is variable and it bears frequent applications in polymer press, paper production, metallic plate cooling, etc. On the other hand, activation energy is an important phenomenon of chemical reaction in flow dynamics of Newtonian and non-Newtonian fluids. The activation energy and chemical reaction have vital applications in food preparing, the mechanism of water and oil emulsions, chemical engineering, and more. So in this project, the impacts of activation energy and binary chemical reaction on MHD two-dimensional boundary layer flow of Williamson nanofluid on an expanding surface of variable thickness embedded in Darcy–Forchheimer porous medium are investigated. Using suitable transformations, the governing equations are transformed into a set of non-linear ordinary differential equations (ODEs). Later, numerical solutions have been achieved by well-known MATLAB inbuilt function 'bvp4c'. Several vital results are explored for variations of involved physical parameters and those are presented in graphical and tabular modes. The achieved results suggest that when wall thickness parameter increases, there is a contrast in behaviors of velocity, temperature and nanoparticle concentration if there is a condition that the shape parameter is greater than or less than unity. For the former case, the above flow properties reduce with wall thickness parameter, whereas, for the latter case, those are showing significant growth. The Brownian motion of nanoparticles causes an increase in temperature and a reduction in nanoparticle concentration, whereas due to thermophoretic force, both temperature and nanoparticle concentration rise. Due to the presence of activation energy in chemical reaction, the nanoparticle concentration enhances, while, temperature decreases(increases) near(away from) the sheet. With increasing reaction rate parameters, nanoparticle concentration diminishes, but temperature increases near the sheet. The surface drag force decreases with Williamson fluid parameter, while it increases with the magnetic parameter, inverse Darcy number, and Forchheimer parameter. On the other hand, the surface heat flux and surface mass flux are decreasing functions of Williamson fluid parameter, magnetic parameter, inverse Darcy number, and Forchheimer parameter. It also reveals that surface heat flux reduces with increasing reaction rate parameters, whereas surface mass flux increases. Finally, for the growth of activation energy parameter, initially surface heat flux rises and surface mass flux declines, but for its larger values, the quantities turn out to be constants. Also, the surface heat and mass fluxes are decreasing functions of thermophoresis parameter. [ABSTRACT FROM AUTHOR]

Hybrid nanofluids are a type of nanofluid that is created by combining two different types of nanoparticles with a traditional fluid. These nanofluids have unique physicochemical properties that make them more effective at transferring heat than traditional nanofluids. This research paper focuses on predicting thermal and energy transport in non-Newtonian biomagnetic hybrid nanofluids that contain gold and silver nanoparticles, using Gaussian process regression (GPR). The study uses blood as the traditional fluid and incorporates the effects of thermal radiation, thermophoresis, Brownian motion and activation energy into the model equation. The governing nonlinear partial differential equations are simplified to a set of ordinary differential equations using similarity replacements. The shooting method, along with the Runge–Kutta-Fehlberg fourth–fifth-order scheme, is used to solve the transformed equations using MATLAB. The results of the study are presented through figures and tables, which include the coefficient of skin friction, Nusselt number, Sherwood number and motile microbe's flux, illustrated with surface plots. The GPR model is developed using four basic function kernels (squared exponential, exponential, rational quadratic and matern32 functions) and evaluated using statistical indicators such as RMSE, MSE, MAE and R. The predicted results and simulated numerical values are in good agreement with the coefficient of determination (R2) of 0.999999 for all parameters. The study also finds that GPR models with exponential kernel functions outperform other kernel functions in both the Oldroyd-B and Casson hybrid nanofluid data sets. However, the findings indicate that nanofluids and hybrid nanofluids have superior thermal qualities and stability, making them promising candidates for various thermal applications including solar thermal systems, automotive cooling systems, heat sinks, engineering, medical areas and thermal energy storage. [ABSTRACT FROM AUTHOR]