High Temperature Research Articles

Synthesis and surfactant properties of sulfonate Gemini surfactants

Abstract In this study, a novel high salinity resistant, high temperature tolerant sulfonate Gemini surfactant (CK-3) for enhanced oil recovery was synthesized and is described. The critical micelle concentration (CMC) of CK-3 is 7.3 × 10−5 mol L−1 with a surface tension at CMC, γ CMC , of 30.88 mN m−1, and a pC20 value of 4.80. Moreover, increasing temperature led to delayed micellization, indicating the superior surface activity inherent in Gemini surfactants. When CK-3 was evaluated as an imbibing agent, an interfacial tension of 8.3 × 10−2 mN m−1 was observed between a 0.3 wt% CK-3 solution and crude oil, facilitated by hydrophobic group interactions which allow crude oil detachment. Finally, CK-3 molecules exhibited stable adsorption on rock walls, influencing wetting reversal. Zeta potential measurements exceeding 30 mV indicated stability. In aged capillary tubes, a 0.3 wt% CK-3 solution exhibited a rise height of 2.9 cm. Imbibition experiments on natural core samples showed a water imbibition efficiency of 8.73 %, compared to a significantly improved efficiency of 50.78 % with a 0.3 wt% CK-3 solution. This study also demonstrated the imbibition process and mechanisms of the CK-3, providing novel insights for the efficient development of unconventional oil reservoirs and the enhancement of crude oil recovery rates.

Test of Mechanical Properties of Composite Recycled Concrete After Medium and High Temperature

Compressive strength is one of the important indexes to test the mechanical properties of concrete. The compressive strength of recycled composite concrete after high temperature is studied by single factor experimental analysis and double factor experimental analysis. Combined with variance analysis, the influence of replacement rate of recycled aggregate, volume incorporation amount of polypropylene fiber and volume incorporation amount of nani CaCO3 on compressive strength of recycled concrete after high temperature was systematically studied. The results show that when the replacement rate of recycled aggregate is 50%, the volume incorporation amount of polypropylene fiber is 0.08%, and nani CaCO3 is 1.2%, the compressive strength of composite recycled concrete reaches the maximum value. Nano CaCO3 is the most significant factor affecting the compressive strength of recycled concrete after high temperature. The significant influencing factors are the incorporation amount of polypropylene fiber and the replacement rate of recycled aggregate.

Heat Capacity of Fish Oil at High Temperatures and Pressures

This paper reports new results from studies of the isobaric heat capacities of OMEGA-3 “950” fish oil provided by SOLGAR INC (USA) at high temperatures and high pressures. The measurements were carried out on a differential scanning calorimeter (ITs-400) with an automatic data acquisition system in the temperature range from 298.15 to 473.15 K and at pressures from 0.098 to 39.2 MPa. The coverage factor for the 95% confidence level for a two-way coverage interval is assumed to be 2. The expanded measurement uncertainty of heat capacity is estimated to be 2.4%, pressure is estimated to be 0.05% and temperature is estimated to be 15 mK. Experimental data on the fish oil isobaric heat capacity as a function of temperature and pressure are approximated by the correlation equation proposed in the work. At atmospheric pressure, the deviations between those calculated by the correlation equation and the current measured data on isobaric heat capacity are within the range of average absolute deviations (AAD) = 0.22% (standard deviation St. Dev = 0.28% and maximum deviation Max. Dev = 0.39%). Additionally, a comparison was made of the state parameters obtained during the experiment and the literature data at the studied parameters.

Trehalose metabolism mediates trade-offs between reproduction and survival in beet webworm, Loxostege sticticalis, under heat stress.

Temperature is an important determinant of developmental and reproductive rates in insects. Here, we investigated the physiological responses of adult beet webworm, Loxostege sticticalis L. (Lepidoptera: Crambidae), to three temperatures (16, 23 and 30 °C) focusing on trehalose metabolism. Exposure of moths to 30 °C accelerated eclosion and ovarian development, but shortened the oviposition period and adult longevity, whereas exposure to 16 °C had opposite effects. Transcriptome analysis revealed that vitellogenin (VG) and vitellogenin receptor (VR) genes were up-regulated at 30 °C, as were numerous genes related to energy metabolism, including those involved in the insulin signaling pathway, the tricarboxylic acid (TCA) cycle, and glycolysis. Expression of the trehalose transporter gene TRET1 was also induced at high temperature, primarily in the ovaries, where trehalose content increased, accompanied by lipid degradation in the fat body. Treatment with the trehalase inhibitor validamycin A reduced female fecundity and longevity at 23 °C, but enhanced the expression of genes related to stress resistance and reproduction, mimicking the effect of high temperature. Besides their practical utility for predicting the oviposition behavior and geographic distribution of L. sticticalis in the field, these results elucidate the various physiological roles of trehalose in L. sticticalis during exposure of moths to high temperature and may provide insights into the relationship between stress resistance and reproduction in insects more generally. © 2024 Society of Chemical Industry.

Mechanical Properties and Fatigue Life Evaluation under High Temperature and Shot Peening Application using AA7001

In some applications, AA7001 may be subjected to high temperature and fatigue. This interaction leads to varying the mechanical and fatigue properties of the above alloy. This work deals with the effects of tensile properties and constant fatigue amplitude performance. Aluminum alloys have a low specific strength, are simple to produce, and are lightweight, which has made them popular in the construction, automotive, marine, and aviation industries. The history of stress and temperature applied to the component has a significant impact on the time-dependent process of creep and strain damage. The purpose of this research is to investigate the behavior of AA7001-T6 when two phenomena, high temperatures creep and fatigue, are combined. Compared to the fatigue life interaction employing shot peening thereby, the fatigue lifetimes were The influence of shot peening on the mechanical and fatigue characteristics of AA7001-T6 was investigated utilizing four different temperatures, including RT, SP+RT, 330°C, and SP+330°C. It has been observed The application of 330°C to the tensile process lowered the ultimate tensile strength of UTS and YS by 21.9 % and 22.3 %, respectively. Shot peening improved the aforesaid percentage, lowering it to 19.2 % and 19.7%, respectively. At a stress level of 400MPa, fatigue life was lowered by 18.18 % owing to an increased temperature of 330°C, and this percentage was reduced to 10.16 % due to creating the compressive residual stresses (CRS) (SP). At (RT), the fatigue strength (endurance fatigue limit) was 229 MPa, but after Shot Peening, it improved to 237 MPa. At 330°C, shot peening increased the improved fatigue limit from 217MPa to 229MPa, resulting in a 5.24 % improvement.

Assessment of heat tolerance and identification of miRNAs during high-temperature response in grapevine

With global warming, heat stress has been recognized as a significant factor limiting grapevine development and fruit quality. MicroRNAs (miRNAs) are a class of small non-coding RNAs known to play crucial regulatory roles in stress resistance. Hence, there is an immediate requirement to cultivate and identify grapevine varieties that are resistant to heat and explore miRNA-mediated heat stress defense mechanisms. In this study, we assessed the thermal resistance of 38 grape germplasm resources and identified a series of miRNAs involved in heat stress resistance. The CK (25°C) and HS (45°C) groups of “Shenyue” cuttings of grapes were used as experimental materials for next-generation sequencing and construct libraries of small RNAs. A total of 177 known and 20 novel miRNAs were detected in the libraries. Differential expression analysis identified 65 differentially expressed miRNAs (DEMs) using the DE-Seq procedure. Furthermore, RT-qPCR validation confirmed complementary expression profiles of eight DEMs and their target genes between the HS and CK groups. Heterologous transformation further identified the function of Vvi-miR3633a downregulated under heat stress in Arabidopsis. In the heterologous expression lines, the survival rate was reduced by high temperature treatment indicating the ability of Vvi-miR3633a to regulate heat resistance. Assessing the heat resistance of grape species and the expression patterns of miRNA in response to high temperatures may reveal the molecular processes of heat resistance regulation mediated by miRNA in grapes under heat stress.

Rapid Thermal Drying Synthesis of Nonthiolated Spherical Nucleic Acids with Stability Rivaling Thiolated DNA

AbstractAttaching DNA oligonucleotides to gold nanoparticles (AuNPs) to prepare spherical nucleic acids (SNAs) has offered tremendous insights into surface chemistry with resulting bioconjugates serving as critical reagents in biosensors and nanotechnology. While thiolated DNA is generally required to achieve stable conjugates, we herein communicate that using a thermal drying method, a high DNA density and excellent SNA stability was achieved using nonthiolated DNA, rivaling the performance of thiolated DNA such as surviving 1 M NaCl, 2 month stability in 0.3 M NaCl and working in 50 % serum. A poly‐adenine block with as few as two consecutive terminal adenine bases is sufficient for anchoring on AuNPs. By side‐by‐side comparison with the salt‐aging method, the conjugation mechanism was attributed to competitive adenine adsorption at high temperature along with an extremely high DNA concentration upon drying. Bioanalytical applications of nonthiolated SNAs were validated in both solution and paper‐based sensor platforms, facilitating cost‐effective applications for SNAs.

β‐Cristobalite thermal expansion and stability in environmental barrier coating systems

AbstractSiC‐based ceramic matrix composites (CMCs) for turbine engine applications require environmental barrier coatings (EBCs) to protect against water‐vapor induced corrosion. A significant limiting factor of EBC operating lifetime is the formation of a SiO2 thermally grown oxide (TGO) at the EBC–CMC interface at high temperature. Its rapid growth as well as displacive β→α cristobalite phase transformation upon cooling induces strains at this interface, which can result in coating spallation. Recent work has explored upon the use of modifier oxides in EBCs to reduce oxidizing specie transport and possibly stabilize the SiO2 TGO. This work utilizes EBC–glass mixtures to characterize the properties of modifier‐stabilized SiO2 and assess its impact in future EBC systems.

Predicting potential hard materials in Nb[sbnd]B ternary boride: First-principles calculations

To identify potential superhard materials, we conducted a comprehensive theoretical investigation of the thermodynamic and kinetic stability, mechanical properties, electronic structure, Debye temperatures and melting point of sixteen ternary transition metal borides NbTMBx (x = 1, 2, 4 and TM = Ti, V, Fe, Co, Ni, Zr, Ru, Hf, W, Os) using first-principles methods. Our findings indicate that, with the exception of NbFeB, NbRuB, and NbWB, all other borides exhibit both thermodynamic and kinetic stability. Notably, NbTiB4, NbVB4, NbZrB4 and NbHfB4 demonstrate superior hardness and enhanced resistance to deformation, with NbTiB4 showing an impressive hardness value of 40.84 GPa, positioning it as a promising candidate for superhard materials. Both NbVB4 and NbTiB4 have very high Debye temperatures and melting points and can be used in high temperature environments. We further explored the mechanical properties of NbTiB4 at elevated temperatures by employing a combination of first-principles and quasi-static methods. Our analysis reveals that the elastic constants and moduli of NbTiB4 decrease with increasing temperature. Additionally, bonding analysis indicates that all NbB ternary borides exhibit hybridization involving metallic, ionic, and covalent interactions, resulting in the formation of exceptionally strong covalent bonds between boron atoms.

Preparation and characterization of quartz ceramic proppant replacing natural quartz sand by solid waste silica fume

AbstractThe improper disposal of industrial wastes will cause environmental pollution and economic losses due to the loss of active ingredients. Solid waste silica fume and pyrolusite powder were used to synthesize quartz ceramic proppant by pelleting and sintering to replace natural quartz sand for unconventional oil and gas exploitation. The effects of pyrolusite powder content and sintering temperature on the apparent density, breakage ratio, and acid solubility of the proppant were thoroughly studied. The phase composition and microstructure of the proppant were characterized by X‐ray diffraction and scanning electron microscopy, respectively. The results revealed that the main crystal phase of the proppant prepared without pyrolusite was cristobalite, while that with pyrolusite was cristobalite and quartz, and the content of quartz phase increased gradually with increasing the pyrolusite content. The addition of pyrolusite remarkably increased the density and improved the performance of the proppant due to the resulting glass phase at high temperatures and the presence of andradite. As adding 20% pyrolusite, the apparent density of the proppant sintered at 900°C was 2.26 g/cm3, while the breakage ratio under 28 MPa closed pressure and acid solubility reached the minimum, 9.89% and 5.3%, respectively, meeting the industrial standard requirements.

Performance evaluation of a racetrack high temperature superconductor winding in an HTS levitation platform

Abstract High temperature superconducting (HTS) is a key technology of next generation high-speed railway systems, which guarantees high current and highly efficient traction power supply. HTS devices can reduce system weight and thus improve loads of vehicles. On high-speed maglev trains, HTS windings wound by second-generation (2G) HTS tapes play an important role in suspension and traction. However, in complex ferromagnetic environments, the performances of windings are notably influenced by the varying magnetic fields. In this paper, a new maglev platform is designed and comprised of a winding of six racetrack HTS coils, an E shape iron core and a magnetic guide rail. The air core structure of the winding is modeled，tested and the electromagnetic characteristics are analyzed for three dimensional (3D) finite element analysis of the platform. An A formulation is used to calculate magnetic vectors A and infer magnetic flux densities and current densities for the structures. After the winding is installed on the iron core and the magnetic guide rail is suspended above the iron core, the air gap between the iron core and the rail is varied from 0 mm to 20 mm in models and experiments. The magnetic fields, critical currents and losses of the winding in cases of the air core and the iron core conditions are used for analysis. The comparison between the air core and the iron core conditions confirms the reliability of the proposed models. This study provides means for analysis of complex superconducting maglev systems.

Theoretical analysis of water-droplet condensation and evaporation in prescribed environment with radiation

Abstract A quasi-explicit algebraic solution of the problem of quasi-steady water droplet heat- and mass-transfer with condensation or evaporation in a prescribed environment including radiation has been obtained. The solution is based on the mass-fraction form of Fick’s law of species diffusive mass transport, which allows accounting for variation in gas density through the diffusion layer surrounding the droplet. A new term, the average vapor supersaturation through the diffusion layer, has been included that allows the model to be extended to environmental conditions significantly outside those for which it is theoretically derived (dilute or near-saturation), even to conditions of relatively high temperature, low relative humidity, and low pressure. The latter two have atmospheric significance because evaporative cooling can induce significant decrease in droplet temperature and possibly induce freezing. Basic modeling assumptions are confirmed by comparison with time-dependent temperature and evaporation-rate measurements of a laboratory laser-heated droplet. Accuracy of the new model is assessed by comparison with exact equations. For temperatures between −30 and 0°C and negligible radiation, relative-error magnitudes in droplet temperature and evaporation rate are less than 5%, even for relative humidity down to 10% and pressure down to 60 kPa. This represents an improvement in accuracy over the conventional model, in which property variations of density and supersaturation through the diffusion layer are not taken into account. Differences in predicted evaporation rates between the mass-fraction and the more common partial-density Fick’s laws, which can be significant (>10% above 70% relative humidity) in coupled, implicit equations, are shown to be made negligibly small (<0.5%) by linearizing about the saturation state.

Heat stress causes chromatin accessibility and related gene expression changes in crown tissues of barley (Hordeum vulgare).

Plant responses to stress caused by high temperatures involve changes occurring at the molecular, metabolic, and physiological levels. Understanding the mechanisms by which plants recognize signals to activate this response is a prerequisite for identifying key genes and signaling pathways and for obtaining heat-tolerant plants. We demonstrated the first implementation of an assay for transposase-accessible chromatin to identify open chromatin regions (OCRs) in crown tissues of barley using three genotypes carrying different allelic forms of the sdw1 gene encoding gibberellin 20-oxidase subjected to elevated temperatures. In parallel, we performed gene expression analysis, which allowed us to relate changes in chromatin state to changes in transcriptional activity. The obtained data revealed that the hypersensitive chromatin regions within the genes were more repeatable than those outside the gene intervals. We observed that prolonged exposure to high temperatures increased chromatin accessibility. Genes with OCRs in their regulatory regions were involved in stress signaling and tolerance, including calcium-dependent protein kinase, mitogen-activated protein kinase (MAPK3), receptor-like cytoplasmic kinase (RLK), TIFY domain-containing transcriptional regulator, bZIP transcription factor, and regulatory protein NPR1. The effect of genotype on gene expression was not as pronounced as that of temperature. By combining results from the differential analysis of chromatin accessibility and expression profiles, we identified genes with high temperature-induced changes in chromatin accessibility associated with expression alterations. Importantly, our data revealed a relationship between the loss of chromatin accessibility in response to heat and the downregulation of genes related to gibberellin signaling.

Conductive Polyethylene/Polyester Textiles with Temperature‐Strengthened Electromagnetic Interference Shielding Efficiency

The advancement of electromagnetic interference (EMI) shielding materials provides reliable protection for the communication technology. However, the performance of conventional EMI shielding materials is significantly diminished in high‐temperature conditions. Herein, an efficient method is proposed to prepare conductive fabrics with temperature‐strengthened EMI shielding performance via chemical plating technique. The as‐prepared polyethylene/polyester‐metallized fabric (PMF) coated with Ni–W–P alloy exhibits outstanding EMI shielding effectiveness (SE) in X band, which is strengthened from 16 to 59 dB with temperature raising from room temperature to 130 °C. Particularly, the corresponding temperature‐strengthened shielding behaviors are investigated through simulations in Computer Simulation Technology. Additionally, PMF presents excellent corrosion resistance (corrosion voltage [Ecoor] of −0.324 V and corrosion current [Icoor] of −6.760 A·cm−2) and admirable Joule heating performance, reaching maximum temperature of 74 °C at only 1.5 V. Therefore, the as‐prepared PMF endows enormous potential in EMI protection under high temperature and harsh environments.

Influence of NiCrAlY coating on anti-corrosion of M951 alloy

M951 alloy is a cast nickel-based super-alloy widely used in gas turbines and aircraft engines, thus a suitable high temperature protective coating must be applied on its surface to enhance the corrosion resistance. In this research, NiCrAlY coating was deposited on M951 by arc ion plating. TGA at 1100 °C, cyclic oxidation at 1000 °C and hot corrosion in molten Na2SO4+25 wt% K2SO4 salt at 850 °C of M951 bare alloy and NiCrAlY coating specimens were investigated respectively. After TGA and cyclic oxidation, mixed oxides of NiO, NiAl2O4, Nb2O5 and Al2O3 formed on M951 surface, which spalled seriously during cyclic oxidation process. Thin, continuous and adhesive α- Al2O3 formed on the surface of NiCrAlY coating after both oxidation process. In molten Na2SO4+25 wt%K2SO4 salt at 850 °C, catastrophic corrosion occurred for the M951 alloy only after 10 hours, while thin and continuous θ- Al2O3 film formed on the surface of the NiCrAlY coating. In a word, NiCrAlY coating greatly improved the high temperature oxidation and hot corrosion resistance of the M951 superalloy. This study will further refine the oxidation and corrosion behaviors of M951 superalloy under different high temperature protective coatings and provides theoretical and experimental basis for the application of M951 superalloy in corrosive environments.

Melting Behavior of CaO at High Temperature and Pressure: A Molecular Dynamics Study

Melting Behavior of CaO at High Temperature and Pressure: A Molecular Dynamics Study

Polyethylene Recycling Via Water Activation By Ball Milling.

Polyethylene (PE) is the most prevalent type of plastic waste and also the most challenging to depolymerize because of its inert carbon-carbon (C-C) bonds.[1] High temperature and noble metals are usually required for depolymerization.[2] To avoid using noble metals, costly reagents and harsh reaction conditions, it is worthwhile but challenging to explore new reaction pathways.[3] We report an unprecedented mechanochemical reaction of PE and water to result in shorter-chain alkanes, alkenes, alcohols, and ketones (Cn, where n ≲ 50), with above 80 % of starting carbon converted into these products, which could be a valuable feedstock for re-entering chemical value chains. This reaction is driven solely by ball milling, without heating and pressurizing. No costly catalysts are used. Instead, only earth-abundant Al₂O₃ was milled with reactants.

New constraints to subduction zone arc and backarc mantle temperatures: a test of the corner flow model

The heat source for the hot volcanic arc of subduction zones and the uniformly warm backarc is not well understood, particularly where backarc extension is absent. In the widely studied corner flow model, the traction of the underthrusting plate drags down the overlying viscous mantle, and the induced shallower seaward flow brings in heat from the landward and deeper asthenosphere. However, earlier comparisons with observations, especially backarc heat flow, gave poor agreement. There are several new constraints to the temperatures and structures above the underthrusting plate and in the backarc, especially those in western North America, for comparison with model predictions. Seismic receiver functions map horizontal boundaries, including the lithosphere-asthenosphere boundary (LAB). Seismic shear wave tomography gives mantle velocity-depth that provides an approximate proxy for temperature. Attenuation of seismic wave speed indicates high temperature or partial melting. The presence of recent backarc volcanics and their geochemistry give the depth and temperature of the LAB. From these constraints in western North America, the LAB reflects ponding of partial melt, is consistently at a depth of 65±3 km and temperature of 1350±25°C, and overlies nearly constant temperature (adiabatic) asthenosphere across the backarc from Mexico to Alaska. These depth and temperature estimates are greatly different from corner flow model predictions. An alternative hypothesis more consistent with these constraints is vigorous small-scale convection in the backarc asthenosphere. Whether or how this convection coexists with the large-scale flow patterns inferred from the interpretation of seismic anisotropy analyses, and to what degree it prevails in the arc-forearc region, deserve further research.

Polyethylene Recycling Via Water Activation By Ball Milling

Polyethylene (PE) is the most prevalent type of plastic waste and also the most challenging to depolymerize because of its inert carbon‐carbon (C–C) bonds.[1] High temperature and noble metals are usually required for depolymerization.[2] To avoid using noble metals, costly reagents and harsh reaction conditions, it is worthwhile but challenging to explore new reaction pathways.[3] We report an unprecedented mechanochemical reaction of PE and water to result in shorter‐chain alkanes, alkenes, alcohols, and ketones (Cn, where n ≲ 50), with above 80 % of starting carbon converted into these products, which could be a valuable feedstock for re‐entering chemical value chains. This reaction is driven solely by ball milling, without heating and pressurizing. No costly catalysts are used. Instead, only earth‐abundant Al₂O₃ was milled with reactants.

High temperature co-processing of stainless-steel slag and red mud: Towards a selective Cr immobilization and harmless treatment

Stainless-steel slag and red mud are bulk metallurgical wastes, which are difficult to reuse due to the complex composition and high environmental risk. To realize their harmless and resource utilization, a collaborative treatment of the stainless-steel slag (AOD slag) and red mud at high temperature was proposed in this study. The influence of the stainless-steel slag to red mud ratio on spinel phase precipitation and crystallization, Cr enrichment and immobilization in the mixed slags were systematically investigated. The results demonstrated that when the stainless-steel slag to red mud ratio was 6:4, the enrichment degree of Cr in spinel phase was 94.12 wt%, and the precipitation amount of spinel reached the highest, 20.98 wt%. In this case, only small amounts of other mineral phases existed, the crystal particle size of spinel phase was larger, and the self-wrapped spinel phases were formed in the stage of cooling. The outer Cr-poor spinel could avoid the abrasion and erosion of the inner Cr-rich spinel in the subsequent physical separation process, thus reducing the risk of Cr6+ dissolution. In the toxic leaching test, the total Cr concentration leached from the mixed slag (stainless-steel slag to red mud ratio was 6:4) was far lower than the national leaching concentration limit of Cr-related ions. The Cr and Fe-rich spinel phases separated from the mixed slag of stainless-steel slag and red mud can be used as the raw material for the production of stainless steel, while the residual Cr-poor slag rich in Ca, Si and Al can be applied in the field of construction.