Peak Temperature Research Articles

A comprehensive analysis of edible and processing quality changes in three whole grain flours induced by dielectric barrier discharge atmospheric cold plasma treatment

SummaryDielectric barrier discharge atmospheric cold plasma (DBD‐ACP) treatment has been used to reduce microbial contamination on the surface of grains, contributing to improved food safety, however, its effect on the edible and processing of whole grain flours is not totally clear. In this study, the effect of DBD‐ACP (5 W, 0–20 min) on the nutritional, physicochemical and structural properties of whole quinoa (WQ), whole highland barley (WHB) and whole triticale (WT) were evaluated. Results showed that the effect of DBD‐ACP treatment on the nutrient composition of different flours differed between grain types. The total polyphenol content of WQ exhibited the most significant changes after 20 min of treatment, decreasing by 62.98%. In addition, DBD‐ACP treatment increased Thr, Phe and Tyr content and accelerated fat oxidation. The results of in vitro simulated digestion experiments indicated that DBD‐ACP treatment significantly reduced (P < 0.05) the final digestibility of three types of whole grain flours. Besides, 20 min of DBD‐ACP treatment significantly changed the physicochemical properties of samples, evidenced by improved hydration and pasting characteristics, increased water absorption index (WAI) and swelling power (SP) and reduced peak temperature (Tp) and gelatinisation enthalpy (∆Hg), especially in WQ20. Further structural analysis showed that DBD‐ACP treatment caused granule cross‐linking and reduced crystallinity of flours. In conclusion, this experiment provided a theoretical basis for the application of DBD‐ACP in grain processing.

Orogen‐scale uniformity of recorded granulite facies conditions due to thermal buffering and melt retention

AbstractGranulite facies metapelitic gneisses collected over a km exposed area of the Kakamas Domain of the Namaqua–Natal Metamorphic Province in southern Namibia all contain similar garnet–sillimanite–cordierite–biotite–quartz–K‐feldspar–ilmenite plagioclase magnetite mineral assemblages. These assemblages are interpreted to have equilibrated at suprasolidus retrograde conditions, and most samples contain distinct biotite‐ or sillimanite‐free peak assemblages. Pseudosection modelling constrains extremely uniform residuum solidus conditions of kbar and °C for the entire Kakamas Domain. Estimated peak metamorphic conditions overlap with these but are more smeared out at between 4 and 7 kbar at 760°C to potentially more than 900°C. The uniformity of residuum solidus conditions is not coincidental, but is a consequence of retrograde re‐equilibration due to minor melt retention after peak metamorphism. Re‐equilibration could only stop once all retained melt had crystallized, which required the concomitant growth of a hydrous mineral to account for its H2O component. Biotite is the most stable hydrous mineral in these rocks, such that the residuum – conditions in the Kakamas Domain reflect the upper‐ stability of biotite, and also corresponds to the intersection of the well‐known biotite–sillimanite melting reaction that consumed all biotite during prograde metamorphism. The calculated melt fertility of the sample suite indicates that the variable amounts of heat consumed to overcome the latent heat of fusion could have caused a 25°C spread in the peak temperature achieved by the most and least fertile samples. Peak temperature in the Kakamas Domain may have been as much as 100°C higher than residuum solidus conditions for specific samples but cannot be confidently constrained as it is obscured by the effects of both thermal buffering during prograde metamorphism and melt retention during retrograde metamorphism. Both processes are an inescapable part of the evolution of all granulite facies rocks, but their effects are most pronounced in fertile rocks like metapelites that are traditionally the preferred lithology for quantifying the – history of exhumed terranes.

Extending a Multiphysics Li-Ion Battery Model from Normal Operation to Short Circuit and Venting

Mitigation of Li-ion battery system fires consists of reliable fault detection and proactive, fast discharge control. Both require modeling of failure modes due to high temperatures and currents between normal operation and thermal runaway. In this work, we present a control-oriented, reduced-order, multiphysics model that captures the electrochemical, thermal, gas generation, mechanical expansion, and venting behavior of NMC pouch cells undergoing an external short circuit (ESC) from different initial state-of-charge (SOC). The model is parameterized through experiments by fitting the solid-electrolyte interphase (SEI) decomposition rate, the cell’s thermal parameters, and the particle solid-phase diffusion parameters to capture the first venting timing, peak temperature, and diffusion-limited electrical behavior at high currents. Using a single parameter set, the multiphysics model can capture behavior during an ESC to predict whether a cell will generate gas and vent, predict the vent timing within 10 seconds of it occurring in the experiment, and maximum cell expansion pressure within 10 kPa for cells that did not vent. The model can also predict the SOC trajectory for cells with a high initial SOC within 6% SOC for the 15-minute discharge or until the cell vents.

Morphological, TGA, and FTIR on Rigid Polyurethane Composite Laminated with Untreated and Treated Bamboo Fiber Roof Insulation

The performance of roof insulation such as polyurethane decreased due to problems such as insufficient absorption and poor thermal insulation performance, especially during rainstorms. The aims of this study are to investigate the physical property and its potential reinforced material such as rigid polyurethane doped with treated and untreated bamboo fiber composite (RPU-BF) at different ratios of 0, 25, 30, 35, and 40% of bamboo fibers as an insulation material for roof applications. The bamboo fibers were treated by using silane coupling agent treatment. The rigid polyurethane composite samples were prepared and then laminated bamboo fiber to overcome the sound problem in roofs. The physical characterization was investigated by Water Contact Angle (WCA), the morphological by Scanning Electron Microscopy (SEM), Thermo-gravimetric Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR) Analysis. The results showed that the treated bamboo fiber had a 192.5° water contact angle as a super hydrophobic property due to the presence of the chemical bonds Si-O-Si and Si-O-C in the silane coupling agent treatment. The morphology showed that 30% ratios of RPU-BF-T30 give the smallest pore diameter size. The peak of thermal degradation temperature of untreated and treated bamboo fiber was increased from 320°C to 350 °C with a weight loss of 80% to 50%. The treated bamboo fiber exhibited peaks at 3010–3040 cm-1 were associated with stronger Si-O-Si bonding, indicating the formation of new chemical bonds between bamboo fiber and silane coupling agent due to the ester bond from the cellulose, lignin, and hemicellulose. Thus, there was a similar trend peak in the functional chemical group in the FTIR spectrum of the RPU-BF composite. This result shows that RPU-BF composite had the potential of the optimum ratio of bamboo fiber as an insulation material for local communities and beneficial to the bamboo industry.

Investigation of microstructure evolution and redox behavior of Ni-GDC cermet by cyclic re-oxidation in CO2

The microstructure and reactivity of Ni-GDC cermet under cyclic oxidation in CO2 conditions were investigated using temperature-programmed reduction (TPR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The XRD results revealed that NiO was formed during the re-oxidation process in CO2. SEM and TPR results demonstrated that nanostructured NiO aggregates were formed on the surface of the sample after being re-oxidized at 400 °C for 1200 min, resulting in an α peak with high reduction activity and a conversion of only 16% from Ni to NiO. In contrast, the samples re-oxidized at 600 °C for 600 min and 800 °C for 240 min were completely oxidized, resulting in reconstructed and sintered NiO with larger particle size, and a β peak with lower reactivity and a conversion of 100%. Redox cycling was further conducted on completely oxidized samples, which showed a decrease in β peak temperature from the first to seventh cycle. The migration and redistribution of sintered NiO towards the exterior were confirmed by comparing SEM images after the first and fourth cycles, which favored an increase in the reactive area. Therefore, this study reveals that lower re-oxidation temperatures (≤400 °C) and an appropriate increase in redox cycles are beneficial for forming surficial nanostructures while hindering the formation of large sintered NiO particles.

Numerical study of combustion flow field characteristics of industrial gas turbine under different fuel blending conditions

Numerous studies have shown that the mixture of fuel and oxidant significantly influences the flow characteristics and pollutant emissions within the combustion flow field. This study investigates the effects of various methane fuel blending ratios (0.19–0.41) on combustion flow, emission characteristics, performance parameters, and field synergies through numerical simulation. Combustion simulation employs the SST k-ω and flame-generated manifold models. The findings indicate that as the fuel blending ratio increases from 0.19 to 0.41, the temperature at the front end of the cyclone gradually rises, resulting in an average outlet temperature increase of 165 K. The outlet temperature uniformity index (γT) shows minimal variation, while the Pattern Factor (PF) and NO emissions at the outlet gradually increase. Additionally, the fuel blending ratio (α) exhibit a limited impact on CO emissions at the outlet. When α ≥ 0.39, the peak temperature is located in the cyclonic region, resulting in an extremely heterogeneous outlet temperature distribution. Under various operational conditions, NO is primarily concentrated in the high-temperature region near the wall, and the pollutant emission merit function (fe) gradually increase with α. The optimum field synergy and overall performance for the low-resistance heat transfer are attained at α = 0.37. Significant velocity shocks are observed in the near-wall regions on both sides of the combustion chamber, when α ≥ 0.35, based on DMD analysis. To achieve low NO emission, uniform outlet temperature, and ensure safe, long-term operation of the gas turbine, the fuel blending ratio of 0.3 to 0.35 is advised.

Exploring enhanced high-temperature resistance: Analyzing the combined impact of fibers and nanoparticles in mortars

This study aims to explore the potential synergistic effect of polypropylene (PP) fiber and different types of nanoparticles to improve the high-temperature resistance of cementitious materials. For that, mortar samples with different PP fiber percentages, 0.6 wt% and 1.2 wt%, were produced. Different percentages of both colloidal nano-silica (CNS), 0.3 %, 0.6 %, and 0.9 %, and nano calcium carbonate (NCC), 0.5 %, 1 %, and 2 %, were used in the study. To test the resistance to elevated temperatures, mortar samples were exposed to different peak temperatures of 300°C, 600°C, and 900°C for 2 h, using unexposed samples as reference. Flexural and compressive strength, water absorption, surface electrical resistivity, and thermogravimetric analysis (TGA) of the heated and unheated samples were conducted. Results showed that, at 300°C heating regime, all samples with 0.6 % PP fiber exhibited an increase in flexural and compressive strength compared to their corresponding reference samples. For instance, specimens containing 0.6 % PP fiber and 2 % NCC content exhibited a 19 % increase in flexural strength compared to the unheated sample, whereas samples with 0.6 % PP fiber and 0.5 % NCC increased 32 % their compressive strength. In contrast, at 600°C, there was a major decline in mechanical properties in all samples, with samples containing NCC exhibiting the lowest amount (average of 61 % reduction in flexural strength and 32 % decrease in compressive strength). In general, a higher dosage of nanoparticles and lower PP fiber content will be better to resist temperatures up to 600 °C.

Projected changes in heat, extreme precipitation, and their spatially compound events over China’s coastal lands and seas through a high-resolution climate models ensemble

China’s coastal lands and seas are highly susceptible to the changing environment due to their dense population and frequent economic activities. These areas experience more significant impacts from climate change-induced extreme events than elsewhere. The most noticeable effects of climate change are extreme high temperatures and extreme precipitation. We employ an ensemble of RCMs (Regional Climate Models) to investigate and project changes in temperature, precipitation, and Compound Heat-Precipitation Extreme events (CHPEs) over selected China’s coastal lands and seas for both historical (1985–2004) and future periods (2080–2099). The multi-model ensemble projects that daily temperature extremes will increase by 2.9 °C to 5.4 °C across China’s coastal lands and seas, with land areas showing a higher temperature increase than marine areas. Extreme precipitation shows a high geographical heterogeneity with a 2.8–3.9 mm d−1 reduction over the 15–25°N marine areas while a 2.2–5.4 mm d−1 increment over the 25°N-35°N land areas. We use the Clausius–Clapeyron relationship to reveal that the peak of daily extreme precipitation will increase by 2–7 mm d−1 and the temperature at which extreme precipitation peaks will increase by 2 °C to 6 °C by warming. The land area of 25–30°N has the highest peak precipitation increase of 9.87 mm d−1 and a peak temperature increase of 6 °C. As precipitation extremes intensify with daily temperature extremes increase, CHPEs are projected to occur more frequently over both land and marine areas. Compared with the historical period, the frequency of CHPEs will increase by 40.9%-161.2% over marine areas, and by 36.2%-163.6% over land areas in the future. The 15–20°N area has the highest frequency increase of CHPE events, and the 25–30°N area has the largest difference in frequency increase under two different scenarios. It indicated that the 25–30°N area will be more easily affected by climate change.

Effectiveness of Ti-in-amphibole thermometry and performance of different thermometers across lower continental crust up to UHT metamorphism

Metabasites are important constituents of deep crustal sections and are the favored rock type for studying lower crustal amphibolite to granulite transitions. However, metapelites may develop a larger number of temperature-sensitive mineral assemblages and are particular useful when extreme ultrahigh temperature (UHT) conditions are envisaged. A recent calibration of the Ti-in-amphibole thermometer by Liao et al. (2021) was supposed to make thermometry on metabasites quick and easy to apply. However, their calibration is based on experiments which were not originally designed to investigate in detail the temperature dependence of Ti in amphibole. In addition, a possible effect of aTiO2 and/or pressure on the Ti content of amphibole was not fully taken into account. This resulted in a calibration uncertainty of ± 70 °C (2σ), much higher than that of other single-mineral thermometers. In this study we firstly test the newly calibrated Ti-in-amphibole thermometer across the mid to lower crustal section of the Ivrea–Verbano Zone (IVZ; NW Italy) and compare the performance of different thermometric techniques across the sequence. Ti-in-amphibole thermometry records increasing peak temperatures from amphibolite (600–700 °C), transition (750–800 °C) and granulite (850–950 °C) zones. Titanium content of amphibole may be modified by retrograde fluid influx returning temperatures c. 200–300 °C lower than in non-altered domains. The comparison reveals that Zr-in-rutile thermometer in pelitic granulites seems to be more prone to post-peak resetting than the Ti-in-amphibole thermometry in nearby mafic rocks. This behavior is also confirmed by amphibole analyses from other UHT localities, where the performance of Ti-in-amphibole thermometry is comparable with that of Al-in-orthopyroxene in pelitic granulites. However, Ti-in-amphibole temperatures are underestimated in rutile-bearing samples and this limitation is not solely restricted to rocks containing high H2O contents as previously thought. Derived constraints on the diffusivity of Ti through amphibole demonstrate the robustness of the Ti-in-amphibole thermometer to later thermal disturbances. However, ad-hoc experiments are still necessary to improve the accuracy and precision of calibration and to extend its applicability. This advance will make mafic granulites routine targets for studies devoted to understanding the regional extent of UHT metamorphism.

Preparation of metal–organic framework-199 (Cu) and their effects on catalytic decomposition of hexahydro-1,3,5-trinitro-s-triazine

In this study, a series of metal–organic framework-199 (MOF-199) products were prepared with copper (Cu) as the metal center and trimesic acid as the organic ligand. The morphological changes of MOF-199 under different preparation conditions and its application in the catalytic thermal decomposition of hexahydro-1,3,5-trinitro-s-triazine (RDX) were studied. The morphological changes of MOF-199 were compared by scanning electron microscopy (SEM), the crystal structures of MOF-199 were analyzed by X-ray diffraction and the effects of MOF-199 with different morphological characteristics on the thermal decomposition behavior of RDX were studied by differential scanning calorimetry. The results showed that MOF-199 with different morphologies could effectively adjust the thermal decomposition process of RDX and reduce the decomposition peak temperature of RDX, and the catalytic effect of MOF-199 was different due to different crystal surfaces exposed. Among them, (110) was a highly active crystal plane with a high catalytic activity. In addition to the crystal plane structure, the defects on the surface of MOF-199 would also affect its catalytic performance. This study provides some theoretical support for the catalytic mechanism of MOFs in the thermal decomposition of nitro compounds.

Application of BPNN algorithm in thermal-hydraulic analysis of unwrapped LFR core

Due to the complex structure of the LFR fuel rod bundle, refined CFD simulation consumes significant computing resources and time, making it difficult to meet the immediate needs of engineering design and research. This paper introduces a method that integrates the sub-channel level thermal-hydraulic analysis code CorTAF-LBE with the BPNN algorithm to analyze the thermal-hydraulic phenomena within the LFR core. The method has been validated by refined simulation results of the THEADES test section, which indicate that the error is within an acceptable range. The feasibility of its application in LFR fuel assemblies was also evaluated. The flow characteristics and temperature distribution in unwrapped LFR rod bundles are investigated. Due to differences in fuel distribution and flow area, the temperature in the central channel is much higher than that in the side and trapezoidal channels. Three accident conditions, including inlet blockage, center blockage, and outlet blockage, were simulated. The corresponding peak temperatures of the fuel cladding were 670 K, 767 K, and 860 K, respectively, representing an increase of approximately 170 K compared to the nominal conditions. The analysis results effectively demonstrate the 3D temperature distribution of the fluid in the rod bundles, which is significant for reactor design and safety analysis of LFRs.

Morphologies of Reactive Nanolayer Stacks Sputtered on Ceramic Low‐Temperature Cofired Ceramic Substrates Having a Micrometer‐Scale Surface Roughness

The deposition of reactive multilayer systems (RMSs) is investigated on low‐temperature cofired ceramic (LTCC) substrates having different surface morphologies. In this study, the morphologies of RMS layers that are deposited on glass‐ceramic LTCC substrates are analyzed. Different surface morphologies are prepared through pretreatments of the LTCC surface. The considered surfaces encompass an untreated natural LTCC surface, a modified sintered LTCC surface by laser ablation, a surface with a deposited metallization layer, and finally, a surface with an additional solder layer put on the deposited metallization layer. The different pretreatments lead to significant differences in the roughness of the LTCC substrates, resulting in different reaction velocities and peak temperatures on the various surface morphologies after the RMS's reaction. As a result, different grades of structural integrity (liftoff, crack formation) between the reacted RMS layer and the LTCC are observed.

Influence of fermentation on the quality of Fijian Theobroma cacao beans over two harvest seasons

ABSTRACT Theobroma cacao beans are cultivated in Fiji by smallholder farms in low volumes, mainly for export. Cocoa beans are often processed under ambient conditions by farmers and cocoa processors. Postharvest processing includes natural fermentation from six to ten days in wooden boxes, followed by sun – drying in the open for up to 14 days. The impact of fermentation conditions on key quality parameters of Fijian cocoa beans, such as temperature profile, pH, and total extractable polyphenol content (TPC) are presented in this study. The quality of fermentation was assessed using a standard method, such as a cut test followed by fermentation index (FI) measurement. A temperature increase to 40°C and variations in the pH of the bean mass were evident during natural fermentation. TPC in the cocoa beans was sensitive to temperature and pH. Fermentation was variable due to weather conditions between harvest seasons. The dry season had the best conditions for fermentation as the peak temperature of the bean mass was 40°C and the FI was high (1.39 ± 0.04) There is a need to improve fermentation during the rainy season. This can be achieved by providing training to Fijian cocoa farmers on using better fermentation techniques.

Multibubble sonoluminescence in supercooled water.

Cavitation in supercooled water has been induced by the short ultrasound pulses of an ultrasonic horn driven at 20kHz. The cavitation during the ultrasonic pulses and occasionally the crystallization events thereafter have been imaged by a high-speed camera. The probability of ice crystallization in dependence on the pulse duration and temperature showed a high chance for the water to remain liquid if sufficiently short bursts of moderate acoustic power were applied. This regime has been used for the assessment of sonoluminescence (SL) from the generated cavitation bubbles in the supercooled liquid state. To this end, light emitting events were summed up over a number of ultrasonic pulses by an image intensifier. SL appeared mostly directly under the tip of the ultrasonic horn and sometimes also a few millimeters below the tip. The intensity of SL events showed a slight rise for a decrease in temperature, i.e., for an increase in supercooling. This behavior is in accord with the SL dependence on temperature above the freezing point and might be attributed to a further lowering of vapor pressure. An increase in the bubble collapse peak temperature for increased supercooling is calculated on the basis of spherical bubble model calculations, which supports the findings. The simulations predict further that the peak temperature will fall off again beyond a certain supercooling level.

Mice with deficiency in Pcdh15, a gene associated with bipolar disorders, exhibit significantly elevated diurnal amplitudes of locomotion and body temperature

Genetic factors significantly affect the pathogenesis of psychiatric disorders. However, the specific pathogenic mechanisms underlying these effects are not fully understood. Recent extensive genomic studies have implicated the protocadherin-related 15 (PCDH15) gene in the onset of psychiatric disorders, such as bipolar disorder (BD). To further investigate the pathogenesis of these psychiatric disorders, we developed a mouse model lacking Pcdh15. Notably, although PCDH15 is primarily identified as the causative gene of Usher syndrome, which presents with visual and auditory impairments, our mice with Pcdh15 homozygous deletion (Pcdh15-null) did not exhibit observable structural abnormalities in either the retina or the inner ear. The Pcdh15-null mice showed very high levels of spontaneous motor activity which was too disturbed to perform standard behavioral testing. However, the Pcdh15 heterozygous deletion mice (Pcdh15-het) exhibited enhanced spontaneous locomotor activity, reduced prepulse inhibition, and diminished cliff avoidance behavior. These observations agreed with the symptoms observed in patients with various psychiatric disorders and several mouse models of psychiatric diseases. Specifically, the hyperactivity may mirror the manic episodes in BD. To obtain a more physiological, long-term quantification of the hyperactive phenotype, we implanted nano tag® sensor chips in the animals, to enable the continuous monitoring of both activity and body temperature. During the light-off period, Pcdh15-null exhibited elevated activity and body temperature compared with wild-type (WT) mice. However, we observed a decreased body temperature during the light-on period. Comprehensive brain activity was visualized using c-Fos mapping, which was assessed during the activity and temperature peak and trough. There was a stark contrast between the distribution of c-Fos expression in Pcdh15-null and WT brains during both the light-on and light-off periods. These results provide valuable insights into the neural basis of the behavioral and thermal characteristics of Pcdh15-deletion mice. Therefore, Pcdh15-deletion mice can be a novel model for BD with mania and other psychiatric disorders, with a strong genetic component that satisfies both construct and surface validity.

Effect of Cubic Crystal Morphology on Thermal Characteristics and Mechanical Sensitivity of PYX

To investigate the influence of the cubic crystal morphology on the thermal properties and sensitivity of 2,6-bis(picrylamino)-3,5-dinitropyridine (PYX), cubic PYX (CPYX) crystals were prepared using the antisolvent method. Scanning electron microscopy (SEM), laser particle size analysis, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the morphology, particle size and structure of the prepared products. The thermal behavior, thermal decomposition kinetics, thermal safety parameters and thermal decomposition mechanism of CPYX were investigated by differential scanning calorimetry–thermogravimetry–mass spectrometry–Fourier transform infrared spectrometry (DSC-TG-MS-FT-IR) and in situ FT-IR experiments. Meanwhile, the mechanical sensitivity of CPYX was determined by means of the explosion probability method. The results showed that the product had a smooth cubic morphology and small crystal aspect ratio with an average particle size (d50) of 10.65 μm, but it had no distinct differences from the crystal structure of raw PYX (RPYX). The thermal decomposition peak temperature, the self-accelerating decomposition temperature and the critical temperature of the thermal explosion of CPYX increased by 7.2 °C, 6.1 °C and 10.4 °C, respectively, compared to RPYX. Similarly, the apparent activation energy increased by 15%. Besides these, the impact sensitivity and friction sensitivity of CPYX decreased by 36% and 20%, respectively, compared to RPYX. The decomposition process of CPYX contains two stages. The first stage involves the breakage of N-H bonds and -NO2 groups with the release of CO2, N2O, NO, HCN and H2O, followed by the thermal decomposition of the resulting intermediate and the release of CO2, N2O and HCN in the second stage.

Efficient Synthesis, Characterization, and DFT Calculation of 4,4’-Azo-1,2,4-triazole

ABSTRACT 4,4’-Azo-1,2,4-triazole (atrz) is a new high nitrogen energetic material with high energy density, high gas yield and wide application prospects, but the low synthesis temperature and long time are the main reasons limiting its application. To achieve efficient synthesis of atrz, the double drop synthesis method was designed to solve the problem of unstable concentration of oxidant (HClO) due to batch feeding. The reaction temperature, reaction time, and molar ratio of reactants of n(4-amino-1,2,4-triazole):n(ClO−) were studied and optimized using the single factor variable method; Characterization and analysis of atrz using theoretical calculations with elemental analysis, infrared spectroscopy, crystal morphology, and nuclear magnetic resonance; The thermal properties and stability of atrz were tested and analyzed using TG-DTA. The results showed that the reaction time of the double drop synthesis method was shortened from 5 hours to 1.5 hours under the conditions of similar yield, and the efficiency was increased by 2.3 times. The optimized process was a reaction temperature of 5°C-10°C, reaction time of 1.5 hours, n(4-amino-1,2,4-triazole):n(ClO−) of 1:2, and the yield reached 73%. The product was white, needle-like crystals, which were determined to be atrz by means of characterization and theoretical calculations. Atrz’s decomposition peak temperature is 309.0°C, and when the temperature is below 271.7°C, atrz is thermally stable. The activation energies of atrz calculated by Kissinger and Flynn-Wall-Ozawa methods were 195.0 kJ·mol−1 and 194.6 kJ·mol−1.

Feasibility study of friction stir joining of aluminium with carbon fibre reinforced thermoplastic composite

During the last decades, environmental concerns and limited resources have set focus of research on lightweight, mechanically high-performing structures for the transportation industry, in order to reduce fuel consumptions and CO2 emissions. Friction Stir Joining (FSJ), as a variant of the Friction Stir Welding (FSW), is an innovative friction-based joining technique for metal-composite hybrid structures. Joining in the plasticized state below the melting temperature of the metal leads to a comparatively small heat-affected zone, so that only minor metallurgical changes occur. Additionally, only a short processing time and no additional weight in form of fasteners is needed. The main objective of this study is to evaluate the feasibility of metal-composite structures via FSJ, intending to enable a macro-mechanical interlocking bonding mechanism. Main focus was given to the integration of an aluminium nub inserted in a carbon fiber-reinforced polyphenylene sulfide (CF-PPS) sheet, to ensure sufficient plasticization of the aluminium part and no degradation in the polymer part. Residual stress arising from the friction stir joining process was also characterised using the Contour method. In this study, aluminium alloy 6082-T6 and CF-PPS composite sheets were used to produce long lap joints. Results have shown that the joints were created at almost constant peak temperature slightly above the melting temperature of the PPS but no physical-chemical changes were detected in the PPS. In addition, the influence of a PPS film as interlayer between the sheets was investigated in order to explore a method for preventing galvanic corrosion. Preliminary results indicate that it is not possible to integrate a metal nub to the CF-PPS without interrupting the PPS film. However, it is possible to create a nub within the PPS film.

Comment on: Carbonaceous matter in ∼ 3.5 Ga black bedded barite from the Dresser Formation (Pilbara Craton, Western Australia) – Insights into organic cycling on the juvenile Earth

Weimann et al. (2024) offer important insights into carbonaceous matter (CM) preserved within bedded barite from the 3.48 billion-year-old Dresser Formation (Pilbara Craton). However, issues in the fitting of CM Raman spectra and the application of Raman CM thermometry cast doubts on the conclusion that 'CM in quartz veins yielded much lower temperatures of ∼ 220 °C, suggesting that quartz-vein associated CM entered the barite after 3.3 Ga' (Weimann et al., 2024). A primary concern is the inaccurate fitting of the CM's D1 band, whose spectral position (typically in the c. 1335–1355 cm−1 range) and full width at half maximum (FWHM) are indicators of thermal maturity (Kouketsu et al., 2014). This commentary emphasizes the implications of misfitting D1 and other issues in fitting the broader CM signals between 1100 and 1700 cm−1. Specifically, the omission of D4 (c. 1250 cm−1) resulted in a systematic overestimation of D1-FWHM and, consequently, unreasonably low thermal maturity estimates. We show that a more precise fitting including D4 – recognizing that CM spectra with a thermal maturity below 300 °C generally display a corresponding shoulder at c. 1250 cm−1 – yields much higher thermal maturity estimates that appear to align closely with the peak temperature (c. 290 °C) of the Dresser Formation's 3.3 Ga metamorphic event. This suggests a (near) syngenetic origin for the quartz-vein-hosted CM, challenging the notion of post-metamorphic infiltration. Consequently, these results also question Weimann et al.'s (2024) interpretation that the much higher thermal maturity (c. 350 °C) of a distinct CM generation, situated within the barite crystal’s growth zonations, stems from metamorphic overprinting. Instead, it can be reconciled with the thermal maturation of the CM during its transportation within the ancient Dresser hydrothermal system, prior to its concentration within the barite.

Modeling heat and mass transfer in metal hydride hydrogen storage systems: Impact of operating parameters and reactor geometry

This work introduces a transient 2D axis-symmetrical model for hydrogen absorption in a cylindrical LaNi5 reactor employing finite volume method with a fully implicit Euler's time integration scheme, coupling equations for heat, mass, and momentum transport. The validated model is used to investigate the impacts of pressure, cooling fluid temperature, and variations in reactor geometry and size on temperature and reacted fraction profiles. The findings reveal that the charging pressure affects both peak temperature and reaction kinetics, whereas cooling fluid temperature predominantly impacts the absorption kinetics. A comparative analysis of two models, one incorporating Darcy's velocity and one without, demonstrates that while Darcy's law introduces numerical instability in the coupled equations, its impact on the model outcomes is negligible. The effect of changing the non-homogeneous Neumann to Dirichlet boundary condition is also demonstrated to anticipate the utilization of phase change materials (PCM) instead of the cooling fluid.