High Temperature Shock Research Articles

Mn doping improves in-situ H2O2 generation and activation in electro-Fenton process by Fe/Mn@CC cathode using high-temperature shock technique

Fe/Mn@carbon cloth (CC) was successfully fabricated through high-temperature shock (HTS) technique and used as cathode modification in heterogeneous electro-Fenton (hetero-EF) process for methylisothiazolinone (MIT) degradation. The nanocrystalline on Fe/Mn@CC electrode is doped with Fe and Mn oxides and coated with carbon layer, which could markedly enhance the electrocatalysis with high electro-chemical active area and low resistance. Fe/Mn@CC modified cathode can efficiently in-situ produce and activate H2O2, showing high electrocatalytic activity to MIT degradation. The 95.2% MIT degradation with in 100 min were achieved under the condition of 30 mA current, 0.75 L min−1 aeration intensity and initial pH = 3. Based on the CV curves and stability test, the high degradation activity revealed the kinetically beneficial regeneration of FeII/MnII in Fe/Mn@CC and activation of H2O2. The electron transfer between FeII/III and MnII/III, together with the direct FeII/MnII regeneration on the cathode, could markedly promote the H2O2 utilization, and eventually lead to MIT degradation.

Formation of Novel Bimetal Oxide In2V2O7 through a Shock Compression Method.

Bimetal oxides with a chemical formula of A2B2O7 have received much attention from plenty of research groups owing to their outstanding properties, such as electronic, optical, and magnetic properties. Among the abundant element combinations of cations A and B, some theoretically predicted compounds have not successfully been synthesized in experiments, such as In2Zr2O7, In2V2O7, etc. In this study, a novel tetragonal pyrochlore-like In2V2O7 nanopowder has been reported for the first time. In2O3 and VO2 powders mixed through ball milling were reacted to form In2V2O7 by shockwave loading. The recovered sample is investigated to be nanocrystalline In2V2O7 powder through various techniques, such as X-ray diffraction, scanning electron microscopy, X-ray energy spectrum analysis, and transmission electron microscopy. The formed In2V2O7 is indexed as a tetragonal cell with a = b = 0.7417 nm and c = 2.1035 nm. Moreover, the formation mechanism of In2V2O7 through a shock synthesis process is carefully analyzed based on basic laws of shockwave. The experimental results also confirm that a high shock temperature and high shock pressure are the two key factors to synthesize the In2V2O7 nanopowder. Our investigation demonstrates the high potential application of a shock-induced reaction on the synthesis of novel materials, including the preparation of new bimetal oxides.

High temperature shock threatens methane production via disturbing microbial interactions in anaerobic digestion

Operational strategies shape microbial interactions determining anaerobic digesting process, but it is unclear whether and how the microbial network properties impact gas generation, especially in the transitional stage after operations. This research examined how the high temperature shock affected microbial diversity and network traits connected with the biogas production in a swine manure-fed anaerobic digester. Rising temperature (from 35 °C to 50 °C) significantly reduced biogas and methane production (p < 0.001) in the transitional stage due to the syntrophic loss of Methanomicrobiaceae and Firmicutes affiliated families. The high temperature shock reduced network modularity and thus caused the system functioning loss. Furthermore, the methanogenic stability was disrupted by high temperature shock (reduced the abundance of Methanosphaera but increased the abundance of Methanoculleus), which may result in the subsequent dysbiosis with other syntrophic communities. These findings suggest that the increased temperature-induced high network complexity and stability, but microbial communities need more time to restore the microenvironment via establishing the interactions of keystone species.

N-doped graphene film prepared by rapid thermal shock for ultra-sensitive temperature reading

Graphene is restricted by its zero-band gap when applying in functional components. However, its band structure can be adjusted appropriately through nitrogen doping. At present, many nitrogen doping processes have been developed such as chemical vapor deposition, thermal annealing and plasma sputtering, but in general these methods are time-consuming and difficult to control the type of nitrogen atom doped. In this work, an in situ high-temperature thermal shock process, with an extremely fast rate of temperature change of more than 104 K/s, is developed and used to prepare the nitrogen doped graphene (NG) films. This novel N-doped process enables the preparation of NG films within 10 s, which is the fastest to the best of our knowledge. Moreover, the type and content of doped nitrogen atoms can be effectively regulated by controlling the composition of precursor films. Optimally, the nitrogen content of NG film reaches 2.26 %, and the proportion of graphite nitrogen is more than 60 %. The electrical conductivity and the average Seebeck coefficient of the NG film are 13,870 S·m−1 and −46.5 μV/K, respectively. Its thermoelectric power factor reaches 30 μW·m−1·K−1, indicating that the NG film has a good prospect of functional application. Furtherly, A NG film-based temperature reading device is developed, which shows ultra-high accuracy and sensitivity in temperature reading within a rather wide temperature range.

Pt–Ni Alloy Nanoparticles via High-Temperature Shock as Efficient Electrocatalysts in the Oxygen Reduction Reaction

Exploring effective synthetic protocols for electrocatalysts of the oxygen reduction reaction (ORR) is vital to the practical application of alkaline fuel cells. Herein, a high-temperature shock (HTS) method is used to synthesize Pt–Ni alloy nanoparticles with various Pt/Ni ratios on a carbon support. The shock is provided by the Joule effect of current passing through the carbon paper. The ultrafast quenching process after the second-long current endows the as-synthesized alloy with an adjustable size and kinetically trapped dislocation features, which provides a degree of structure tuning toward electrocatalysts with improved ORR performance. Among the series of catalysts with various compositions, catalysts with a Pt/Ni ratio of 1 display a half-wave potential of 0.9 VRHE with a corresponding specific activity of 0.87 mA cm–2, roughly 6-fold that of the commercial Pt/C catalyst. The half-wave potential shows a limited negative shift after 5000 cycles of the durability test, proving the feasibility of fabricating carbon-supported Pt alloy catalysts from HTS with remarkable ORR activity and stability. The influence of composition and strain on the performance is investigated by the density-functional theory calculation.

Mechanical properties and failure characteristics of granite treated with a combined water–air cooling cycle

Granite is the main material used to enhance geothermal reservoirs, and its mechanical properties play a key role in the safe and efficient development of geothermal materials. High temperature and cold shock issues are often encountered during the process of geothermal development. For this reason, numerous studies have been conducted on the mechanical properties of granite treated at different temperatures and with various cooling methods. In addition, granite is often affected by combined water-air cooling, which affects the development direction and stability of reservoir heat transfer channels. However, few studies on the mechanical properties of granite treated with combined water-air cooling have been conducted thus far. In this study, uniaxial compressive tests were conducted on granite to study the effect of localized water cooling at different temperatures and numbers of heating-cooling cycles. The results show that the thermal cracks in granite subjected to combined cooling treatments exhibited regional distribution characteristics with temperature and cycle times; there were no apparent thermal cracks at 200 °C, thermal cracks were mainly distributed in the water-cooling zone between 300 and 400 °C, and thermal cracks were distributed throughout the granite specimens above 500 °C as the number of cycles increased. Within 300 °C, the peak axial stress and Young's modulus of the granite exhibited slow linear decreasing trends with temperature and cycle times, but the peak axial stress and Young's modulus exhibited nonlinear decreasing characteristics when the temperature exceeded 400 °C. The failure mode gradually changed from brittleness to ductility. Above 500 °C, thermal cracks near the interface of the water-cooling and air-cooling zones became denser than those in the other two areas (the water-cooling and air-cooling zones) as the number of cycles increased, and the splitting failure during loading failure shifted from the water-cooling zone to the interface of water cooling and air cooling. The temperature condition for fracture and peeling between the air-cooling and water-cooling zones of the granite was 600 °C.

Ultrafast Porous Carbon Activation Promises High-Energy Density Supercapacitors.

Activated porous carbons (APCs) are traditionally produced by heat treatment and KOH activation, where the production time can be as long as 2 h, and the produced activated porous carbons suffer from relatively low specific surface area and porosity. In this study, the fast high-temperature shock (HTS) carbonization and HTS-KOH activation method to synthesize activated porous carbons with high specific surface area of ≈843 m2 g-1 , is proposed. During the HTS process, the instant Joule heating (at a heating speed of ≈1100 K s-1 ) with high temperature and rapid quenching can effectively produce abundant pores with homogeneous size-distribution due to the instant melt of KOH into small droplets, which facilitates the interaction between carbon and KOH to form controllable, dense, and small pores. The as-prepared HTS-APC-based supercapacitors deliver a high energy density of 25Wh kg-1 at a power density of 582 W kg-1 in the EMIMBF4 ionic liquid. It is believed that the proposed HTS technique has created a new pathway for manufacturing activated porous carbons with largely enhanced energy density of supercapacitors, which can inspire the development of energy storage materials.

A novel FEM-FVM coupled method of evaluating the explosion shock wave of a thermobaric bomb on the internal and external flow characteristics of aircraft

The high-temperature and high-pressure shock waves generated after the explosion of a thermobaric bomb have a considerable impact on the aerodynamic characteristics of aircraft. Taking a typical thermoelastic model as the object, the explosion process was calculated by LS-DYNA software. The obtained pressure–time history curve data were written into a UDF function and coupled with Fluent software. At the same time, the afterburning effect of the combustion agent was considered. The influence of the explosion effect on the flow field characteristics of an M6 wing and the inlet of a turboprop engine was evaluated. Thus, an FEM-FVM co-simulation method was established. The results showed that when affected by the explosion shock wave of a thermobaric bomb, the maximum changes in the lift, drag, and pitch moment of an M6 wing in a very short period of time are 29, 13, and 7 times those of the original, respectively, and the effect is mainly reflected in the first shock wave. For the flow field in the intake duct, the total pressure recovery coefficient of the outlet section is reduced by up to 68%, and the distortion rate is increased by up to 325%. This change may even lead to engine surge and shutdown. Moreover, regardless of internal or external flow, the high-temperature airflow after detonation also affects the thermal protection ability of the wing or the inlet profile. All these factors need to be considered comprehensively in the design phase of the aircraft.

The Los Angeles martian diabase: Phosphate U-Th-Pb geochronology and mantle source constraints

In situ laser ablation inductively coupled mass spectrometry (LA ICP-MS) is used to determine the U-Th-Pb age of the phosphates ferromerrillite and apatite in the Los Angeles shergottitic meteorite. The initial 207Pb/206Pb was refined by analyzing K-rich diaplectic glass. LA ICP-MS mapping was used to document zones of elevated U and Th content and to establish textural controls on isotope ages. By critically assessing dispersion in the U-Th-Pb dataset due to Pb-diffusion in phosphates during high-temperature shock metamorphism, and as a result of subsequent terrestrial contamination, we obtain a best-estimate U-Pb age of 169 ± 5 Ma anchored at an initial 207Pb/206Pb of 0.98390 ± 0.00018. This is statistically indistinguishable from a joint-isochron age of 179 ± 6 with initial 208Pb/206Pb of 2.5151 ± 0.0028. These results complement previously determined Rb-Sr and Sm-Nd isotope ages and provide independent evidence for LA having crystallized as a medium-grained basic rock from a thick lava flow or high-level intrusion in the late Amazonian at ∼170 Ma. In the context of martian mantle evolution, the initial common-Pb values suggest that Los Angeles originated from a source (µ2 ∼ 3.2) that is similar to enriched members of the shergottite meteorite clan. The U-Th-Pb systematics of both ferromerrillite and apatite were locally affected by diffusive Pb-loss in thin U-enriched marginal domains and more profoundly in shock-induced melt pockets where temperatures briefly exceeded 2000 °C. The results reveal: (1) how precise U-Pb ages can be attained from phosphates; (2) the importance of microtextural contextualization of isotope data; (3) that the timescales of cooling from shock conditions were sufficient to promote local diffusive re-equilibration of Pb over 10 s of microns; and (4) that LA ICP-MS mapping can be used to locate domains with the highest U/Pb and Th/Pb, which increases precision on lower intercept ages and isochron regression lines.

Effect of surface brittle-to-ductile transition on high-temperature thermal shock resistance of Al2O3 ceramics

The effect of surface brittle-to-ductile transition (BDT) on the high-temperature thermal shock resistance (TSR) of Al2O3 ceramics was investigated by quenching in a cold compressed-air flow. The brittle-to-ductile transition (BDT) and transition temperature were determined from the transformation in fracture mechanism via measuring flexural strength at elevated temperatures. Effects of cooling rate on the residual strength and microstructural evolution of Al2O3 ceramics were systematically studied. Results showed that the BDT temperature in Al2O3 ceramics was around 1000 °C. The BDT mechanism is associated with the softening of the grain boundary glass phase, which permits a certain degree of crack passivation to reduce thermal stress concentration. Compared with the original strength of 375 MPa, the residual strength of the specimen decreased rapidly to 190 MPa at a final temperature of 700 °C, while the residual strength of the specimen was maintained to 352 MPa at a final temperature of 1000 °C. The appearance of surface BDT in Al2O3 ceramics during the high-temperature thermal shock process produces a favorable impact on improving the residual strength of specimens by blunting the crack tip and reducing the surface thermal stress. Therefore, the surface BDT in Al2O3 ceramics is beneficial to the improvement of the high-temperature TSR of Al2O3 ceramics.

Interface Engineering Between Multi‐Elemental Alloy Nanoparticles and a Carbon Support Toward Stable Catalysts (Adv. Mater. 9/2022)

Hierarchical Catalysts In article number 2106436, Liangbing Hu and co-workers report an interface engineering strategy to improve the stability of multi-elemental alloy (MEA) nanoparticles on a carbon substrate. The MEA-oxide–carbon hierarchical catalysts synthesized by a rapid high-temperature shock method demonstrate excellent thermal and electrochemical stabilities, and hold great promise for various catalytic applications.

Experimental study on the effect of high-temperature oxidation coal mechanical characteristics.

After long-term oxidation and energy storage, broken coal body borehole walls and drainage shaft walls may cause spontaneous combustion during gas extraction. The high-temperature thermal shock caused by the spontaneous combustion of coal incurs thermal damage on adjacent coal, which, in turn, causes changes in the mechanical properties of the coal. However, only a few studies have been conducted in this context, which has limited our understanding of the thermal damage characteristics of coal bodies in such situations. This study aimed to experimentally investigate the correlation between the crack evolution law and the mechanical properties of coal bodies at different temperatures (50-300°C) using heat-force loading considering Ping Mei No. 10 coal mine as the research object. The results suggest that the coal body experiences a large amount of visible damage, and becomes increasingly complex. At 50-300°C, some indexes (such as longitudinal wave velocity, Poisson's ratio, compressive strength, elastic modulus, impact energy index, and pre-peak strain) are positively correlated with temperature. In addition, the dynamic failure time and temperature show a negative correlation, and the overall change slope is small. The relationship between each index and temperature at 200-300°C is opposite to that at 50-200°C, and the overall change slope is larger. Moreover, when the oxidation temperature exceeds 200°C, the destruction of the coal body changes from elastic brittleness to ductility-plasticity. High-temperature oxidation incurs irreversible thermal damage of coal. Hence, it is necessary to focus on the changes in mechanical properties of coal after a spontaneous combustion process is extinguished.

Shock experiments with an l-alanine solution and implications for the cometary delivery of amino acids and dimers with enantiomeric excesses to the early Earth

Shock experiments on an aqueous l-alanine solution were undertaken to examine the significance of cometary impacts in supplying prebiotic compounds to the early Earth. The shock pressures and temperatures ranged from 6.5 to 34.0 GPa and 516 to 963 K, respectively. Alanine in the shocked samples decreases in abundance and has higher d/l ratios as the shock temperature increases. The shocked sample at 963 K contained 33% of the starting alanine, which had a d/l value of 0.51. The shocked samples above 643 K all contained isomers of the alanine dimer Ala–Ala, including l-Ala–l-Ala, l-Ala–d-Ala, d-Ala–l-Ala, and d-Ala–d-Ala. A comparison of our study with previous studies indicates that water inhibits the decomposition of alanine and promotes racemization during shock compression. We calculated the shock temperatures at various impact velocities to determine the impact velocity at which alanine can survive when comets and meteorites impact the land or ocean at different impact angles. This impact velocity was much lower for comets than meteorites. The reduction in alanine decomposition caused by water is compensated for by the high shock temperature produced by the high porosity of comets. However, considering that comets are effectively decelerated by airburst and contain large amounts of organic materials, comets would be more important than meteorites in terms of delivering prebiotic compounds, including amino acid dimers with ll enantiomeric excesses, to the early Earth. Comets are likely to have played a key role in the biogeochemical evolution of the early Earth.

Behaviour of Al, Co, Cr, Ni-based high entropy alloys under high-temperature thermal shock oxidising conditions

This study aims to comprehensively determine the behaviour of Al,Co,Cr,Ni-containing high entropy alloys, i.e. Al25Co25Cr25Ni25, Al20Co25Cr25Ni25Si5 and Al9.1Co18.2Cr18.2Fe18.2Ni36.3 (at%), in high-temperature oxidising atmospheres under thermal shock conditions. In each case, significant mass loss was not determined, indicating very good scaling-resistance. Investigations on the morphology, chemical and phase composition of the alloys after the oxidation process indicate that Cr2O3 is mainly responsible for the good protection, along with Al2O3 in the first two cases. The sample with the highest aluminium content in its scale is Al20Co25Cr25Ni25Si5. Consequently, this material seems to demonstrate the best oxidation properties among the studied alloys.

Ultrafast Regenerating Spent LiCoO2 Lithium‐Ion Batteries into Bifunctional Electrodes for Rechargeable Zn‐Air Batteries

AbstractThe ever‐increasing use of lithium‐ion batteries (LIB) results in piles of spent batteries, which threats the environment and the supply chain of strategic metals. Developing sustainable recycling strategies for the cathode of spent LIB can bring about promising environmental and economic benefits. In this work, we present an ultrafast high temperature shock process for regenerating typical LiCoO2 (LCO) spent cathodes into the carbon layer/Co3O4 composite (C/CO). The nanosized Co3O4 provides large active sties exposure, while the graphitized carbon layer can potentially enhance the electronic conductivity towards oxygen evolution and oxygen reduction (OER and ORR) catalysis. Benefiting from the enhanced active sties exposure, electronic conductivity, and the synergistic effect between the two domains, the C/CO composite shows efficient bifunctional (OER and ORR) electrocatalytic properties. The OER overpotential (at 10 mA cm−2) and ORR on‐set potential reach 245 mV and 0.90 V, respectively. Moreover, the aqueous rechargeable Zn‐air batteries using C/CO composite as air cathodes display high specific capacity (698 mAh g−1), power density (131 mW cm−2), and as well as cycling stability. This work provides a waste to treasure way that is eco‐friendly, low‐cost, and ultrafast for regenerating the spent LIB for further applications in energy storage systems.

A numerical study of carbon dioxide radiation and transmission property in high temperature shock layer

A numerical study of carbon dioxide radiation and transmission property in high temperature shock layer

Inducing High Temperature Shock at Onset of the Anthesis and Its Effect On Grain Quality of Wheat Cultivars

Uncertain heat shock by a rapid increase in temperature particularly at the critical growth stage affects plant productivity. The study aimed to assess qualitative changes in wheat grains when plant exposed to high temperature shock (HTS) at starting anthesis for limited durations (48, 72 and 96h). Selected wheat cultivars (Pirsabak-2005, Pakhtunkhwa-2015, Pakistan-2013, DN-84, P-2, P-12 and P-18) were exposed to extending HTS effective from anthesis in the field covering plants within plastic tents for a limited duration. The experiment was conducted in 2017-18 and 2018-19 at the Research Farm, the University of Agriculture Peshawar, Pakistan in a randomized complete block design, in three replications. Temperatures inside and outside plastic tents were manually noted. Two years mean data showed significant effects of HTS on the wheat grain quality. Imposed HTS for 48, 72 and 96h resulted in a reduction on grain amylose by 23, 39 and 48% and wet gluten by 16, 25 and 36%, respectively when compared with the control (i.e. no HTS). Contrary to this, as compared to the control treatment an increase noted in the grain amylopectin by 7, 11 &amp; 17% and in the grain N-content by 13, 28 &amp; 41% with imposing HTS extending to a duration of 48, 72 and 96h, respectively. The study concluded adverse effects of HTS at the anthesis stage on wheat grain quality disturbing amylose and amylopectin ratios, which latter on brought changes in floor structure and gluten elasticity. However, cultivar did differ to respond to the changes but have the option to choose the best one.

Enhanced lipid productivity coupled with carbon and nitrogen removal of the diatom Skeletonema costatum cultured in the high CO2 level

Rising CO2 is causing noticeable environmental and social problems and thus to reduce CO2 emission is becoming extremely urgent. Biodiesel from microalgae is considered to have immense potential in replacing fossil fuels and reducing CO2 emission, apart from remediating eutrophic waters. How to increase biodiesel yield with low cost is the key for successful application of biofuel. In this study, we used high CO2 concentration (5%) to culture the marine diatom Skeletonema costatum and aimed to enhance lipid productivity through the combination of low temperature shock. High CO2 first inhibited the specific growth rate but then increased it after a 24 h pause of gas supply. High CO2 increased lipid content by 26.8% and lipid productivity by 29.0%; the combination with low temperature shock resulted in a further stimulation (50.0% for lipid content and 42.5% for lipid productivity). High CO2 also stimulated carbon and nitrogen assimilation, leading to the increase of carbon and nitrogen removal rates by 28.9% and 22.7%, respectively; while low temperature shock did not show a significant effect. High CO2 increased maximum photochemical efficiency but reduced non-photochemical quenching, with insignificant effects of low temperature shock on either. Therefore, the stimulating effects of high CO2 on lipid accumulation could be attributed to increased photosynthetic performance because photosynthesis can supply ATP and carbon skeleton for lipid synthesis. These findings indicate the success of the combination of high CO2 and low temperature shock in enhancing algal lipid yield and bioremediation capacity.

Shock synthesis of nanocrystalline La2Ti2O7 powder

Perovskite La2Ti2O7 nanocrystalline powder was obtained through the shock synthesis method. In the study, La2O3 and TiO2 powders were mixed through ball milling and, subsequently, shocked by a flyer at a velocity of 3.2 km/s. After shock treatment, the sample was recovered and characterized via various techniques, such as x-ray diffraction, Raman, scanning electron microscope, transmission electron microscope, and ultraviolet-visible diffuse reflection spectrum analysis, to find the presence of La2Ti2O7 nanocrystalline powder with an average grain size of approximately 30 nm in the recovered samples with different yields. Moreover, the results further confirm that the high shock temperature and long ball milling treatment induce higher activation of precursors to improve the La2Ti2O7 content in the recovered samples. By adjusting the relative density of precursor and the ball milling period, pure La2Ti2O7 nanocrystalline powder was obtained. The formation mechanism of La2Ti2O7 was carefully illustrated. This study presents a new method to synthesize La2Ti2O7 nanocrystalline powder by detonation-driven flyer impact.

One-second synthesis of carbon-supported Pd via Joule heating and enhanced electrocatalytic performance in methanol oxidation through promoting effect of multi-metallic oxides

Developing highly efficient anodic catalyst is important, yet still challenging. Here, hybrid catalyst of Pd with multi-metallic oxides (Pd/MMO) was synthesized in one step on commercial carbon black with one-second high-temperature shock through Joule heating. Thanks to the promoting effect of multi-metallic oxides, the mass activity was enhanced by a factor of 1.8 over pristine Pd. The improvement was caused by the synergistic effect of multi-metallic oxides as its activity also surpassed that of hybrid catalysts of Pd with unary oxides. The superior performance of Pd/MMO was well maintained after a two-hour durability test, which showed the best anti-poisoning capability among all the catalysts evaluated. It demonstrated Joule-heating as a simple, fast, and powerful tool for synthesizing hybrid catalysts with excellent performance.