Elevated Temperatures Research Articles

Reusable adsorbent of magnetite in mesoporous carbon for antibiotic removal.

This study aims to evaluate the feasibility of an innovative reusable adsorbent through adsorption-degradation sequence for antibiotic removal from water. The magnetite/mesoporous carbon adsorbent was prepared using a two-step method of (i) in situ impregnation of magnetite precursor during resorcinol formaldehyde polymerization and (ii) pyrolysis at elevated temperature (800 °C). XRD spectra confirmed that magnetite (Fe3O4) was the only iron oxide species present in the adsorbent, and thermogravimetric analysis revealed that its content was 10 wt%. Nitrogen sorption analysis showed that Fe3O4/carbon features a high fraction of mesopores (> 80 vol.%) and a remarkable specific surface area value (246 m2g-1), outstanding properties for water treatment. The performance of the adsorbent was examined in the uptake of three relevant antibiotics. The maximum adsorption uptakes were ca. 76mgg-1, ca. 70mgg-1, and ca. 44mgg-1 for metronidazole, sulfamethoxazole, and ciprofloxacin, respectively. All adsorption curves were successfully fitted with Langmuir equilibrium model. The regeneration of adsorbent was carried out using Fenton oxidation under ambient conditions. After three consecutive runs of adsorption-regeneration, Fe3O4/carbon maintained its performance almost unchanged (up to 95% of its adsorption capacity), which highlights the high reusability of the adsorbent.

Water‐Assisted Reprocessing and Shape Programming of Epoxy Vitrimer

Water‐Assisted Reprocessing and Shape Programming of Epoxy Vitrimer

Temperature-Induced Luminescence Intensity Fluctuation of Protein-Protected Copper Nanoclusters: Role of Scaffold Conformation vs Nonradiative Transition.

Protein-scaffolded atomically precise metal nanoclusters (NCs) have emerged as a promising class of biofriendly nanoprobes at the forefront of modern research, particularly in the area of sensing. The photoluminescence (PL) intensity of several nanoclusters showed a systematic temperature-dependent fluctuation, but the mechanism remains ambiguous and is poorly understood. We tried to shed some light on this mechanistic aspect by testing a couple of hypotheses: (i) conformational fluctuation of the protein scaffold-mediated PL intensity fluctuation and (ii) PL intensity fluctuation due to the variation in the radiative and nonradiative transition rates. Herein, the PL intensity of the lysozyme-capped copper nanocluster (Lys-Cu NC) showed excellent temperature dependency; upon increasing the temperature, the PL intensity gradually decreased. However, contrasting effects can be seen when the nanocluster is exposed to a chemical denaturant (guanidine hydrochloride (GdnHCl)); the PL intensity increased with the increase in the GdnHCl concentration due to the change in the ionic strength of the medium. This discrepancy clearly suggests that the thermal PL intensity fluctuation cannot be explained by a change in the scaffold conformation. Furthermore, upon closer investigation, we observed a 2-fold increase in the nonradiative decay rate of the Lys-Cu NC at the elevated temperature, which could reasonably explain the decrease in the PL intensity of the nanocluster at the higher temperature. Additionally, from the result, it was evident that the protein scaffold-metal core interaction played a key role here in stabilizing each other; hence, the scaffold structure remained unaffected even in the presence of chemical denaturants.

Efficient Decoupled Electrolytic Water Splitting in Acid through Pseudocapacitive TiO2.

Water electrolysis remains a key component in the societal transition to green energy. Membrane electrolyzers are the state-of-the-art technology for water electrolysis, relying on 80°C operation in highly alkaline electrolytes, which is undesirable for many of the myriad end-use cases for electrolytic water splitting. Herein, an alternative water electrolysis process, decoupled electrolysis, is described which performed in mild acidic conditions with excellent efficiencies. Decoupled electrolysis sequentially performs the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), at the same catalyst. Here, H+ ions generated from the OER are stored through pseudocapacitive (redox) charge storage, and released to drive the HER. Here, decoupled electrolysis is demonstrated using cheap, abundant, TiO2 for the first time. To achieve decoupled acid electrolysis, ultra-small anatase TiO2 particles (4.5nm diameter) are prepared. These ultra-small TiO2 particles supported on a carbon felt electrode show a highly electrochemical surface area with a capacitance of 375Fg-1. When these electrodes are tested for decoupled water splitting an overall energy efficiency of 52.4% is observed, with excellent stability over 3000 cycles of testing. This technology can provide a viable alternative to membrane electrolyzers-eliminating the need for highly alkaline electrolytes and elevated temperatures.

Investigation of the impacts of regeneration temperature and methanol substitution rate on the active regeneration of diesel particulate filter in a diesel-methanol dual-fuel engine

Methanol (CH3OH), a sustainable fuel derived from many renewable resources, simultaneously reduces nitrogen oxides (NOx) and particulate matter (PM) in diesel-methanol dual-fuel engines. This study systematically investigated the effects of regeneration temperature and methanol substitution rate (MSR) on the performance of diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and the temperature characteristics of DPF substrate during active regeneration. The experimental results show that the DOC catalytic oxidation of unburned CH3OH has a conversion rate of more than 97.5 % across various MSR. DPF inlet temperature rose faster with higher MSR. Elevated regeneration temperature reduced effective regeneration times and diesel equivalent consumption. Within active regeneration conditions with MSR increases, both effective regeneration times and diesel equivalent consumption initially decreased and then increased as the MSR rose. At MSR = 30 %, the duration of effective regeneration times during DPF active regeneration was minimized, and diesel equivalent consumption at MSR = 30 % experienced an improvement of 22.52 % compared to MSR = 0 %. The highest DPF substrate temperatures across various MSR levels are consistently observed at T6 position within the DPF. This study can provide a theoretical basis for the active regeneration of DPF in methanol-diesel dual-fuel mode.

Improving heat transfer in indirect liquid-based battery thermal management systems through turbulator-equipped conical flow paths

To guarantee the safe operation of Li-Ion Cells (LICs) in various applications, such as electric vehicles, an efficient Battery Thermal Management System (BTMS) is necessary. The design of BTMSs, as documented in the literature, typically involves the use of cooling channels with uniform and smooth configurations. However, these configurations encounter the challenge of temperature non-uniformity in the battery module, which stems from elevated coolant temperatures along the flow direction. In this study, a 3D numerical analysis is conducted to develop a novel indirect liquid-based cooling system for the BTMS of a module with cylindrical LICs. The study explores the effects of conical cooling channels, both with and without twisted turbulators, across various coolant mass flows during a 2C discharge process of LICs. Within the studied ranges, diverging cooling channels improve the overall thermal and hydraulic performance of the BTMS by an average of 40%, increasing the heat transfer coefficient by a maximum of 32.6%, and decreasing pressure drop by up to 35.1%. The application of turbulators proves effective in reducing the maximum temperature difference within the LICs, demonstrating a decrease of approximately 34.2% at the minimum mass flow rate and 74.4% at the maximum mass flow rate. This emphasizes the more substantial impact of turbulator utilization at higher coolant mass flow rates. An increased coolant flow rate leads to a significant enhancement of the heat transfer coefficient, ranging from 70.5% to 79.0% for the BTMS incorporating turbulators. Moreover, the study highlights a more pronounced impact of increasing mass flow rates in the BTMS designed with converging cooling channels compared to those designed with diverging channels. Finally, the results of this analysis demonstrate that the proposed system is capable of efficiently regulating the temperature of the entire battery module, ensuring that it consistently maintains a normal and safe operational range suitable for vehicular applications (below 40 °C).

Microstructural and Residual Properties of Self-Compacting Concrete Containing Waste Copper Slag as Fine Aggregate Exposed to Ambient and Elevated Temperatures

In recent times, with rapid development in the construction sector, the use of enormous amounts of materials is required for the production of concrete. Fire penetrates concrete, leading to chemical contamination, small cracks, and lightening. These effects can significantly change the properties of concrete’s structure, reduce its strength and durability, and also change the behavior of the structure and lead to effects on the environment. An attempt was made to study the effects of elevated temperature on the mechanical characteristics of self-compacting concrete (SCC) with by-products including fly ash as a partial replacement for cement and waste copper slag as a partial replacement for fine aggregate at 0%, 10%, 20%, 30%, 40%, 50%, 60%, and 70%. The SCC specimens were subjected to elevated temperatures ranging from 200, 400, 600, and 800 °C, respectively, for a steady-state of two hours in a digital muffle furnace. The residual compressive strength, mass loss, ultrasonic pulse velocity, and residual density along with a visual inspection of cracks and color changes were observed. In this study, with over 400 °C temperatures, surface fractures appeared. The residual compressive strength (R-CMS) of all the individual temperatures of the SCC-WCS% mixes exhibited a gain in strength range from 31 to 34 MPa at 400 °C, 26 to 35 MPa at 600 °C, and 22.5 MPa to 33.5 MPa at 800 °C, respectively. Microstructural analysis of SCC-WCS% mixtures subjected to elevated ambient temperatures is carried out with a scanning electron microscope (SEM) and X-ray diffraction (XRD).

High temperature dry sliding wear behaviour of selective laser melted Ti-6Al-4V alloy surfaces

The present study investigates the sparsely documented tribological performance of selective laser-melted Ti-6Al-4V over a wide range of temperatures (room temperature to 450 °C). The evolution of wear mechanism was traced by examining the phase changes, chemical composition, and morphology of wear tracks in the material. The native oxide layer developed on the surface of the material was found to mitigate adhesive wear during dry sliding at room temperature. At elevated temperatures, this oxide layer contributed to oxidative wear, as evidenced by the formation of a tribo-oxide layer with increased oxygen penetration. Further, abrasive wear was found to increase with increasing temperatures, which could be attributed to the presence of entrapped oxidized wear particles (third-body wear) and material softening.

An elastoplastic semi-analytical solution for enhanced geothermal wellbore stability considering temperature-sensitive failure criterion

Temperature alters the rocks’ mechanical behavior and influences the stability and operation of enhanced geothermal wells. The stability of the well is a concern during construction, just after the construction, at the time of production, and injection. Most available analytical and semi-analytical solutions for wellbore stability do not account for rock's temperature-dependent yield behavior. In the present study, we proposed an elastoplastic constitutive model based on the temperature-sensitive yield criterion and a semi-analytical solution for wellbore stability. The applicability of the constitutive model is demonstrated by comparing the experimental results of Comiso limestone with the model output. The model elastic perfectly plastic assumption reasonability captures the stress-strain behavior at elevated temperatures. Temperature-sensitive yield criterion effectively predicts the yield point of Comiso limestone, even the substantial decay in yield stress after the temperature of 400 οC. The semi-analytical solution of wellbore stability analysis is validated using FE (Finite element) analysis. An implementation of the semi-analytical solution is showcased for a vertical wellbore, considering changes in in-situ stresses and temperature. A parametric analysis establishes that external factors, like vertical stress increase, do not consistently decrease the size of the plastic zone. Instead, a specific threshold of vertical stress exists at which the plastic zone radius reaches its minimum value. In the presented case, the least radius of the plastic zone is observed for in-situ vertical stress of 80 MPa. Furthermore, the parametric study examines the impact of horizontal stress, support pressure, temperature, and dilation parameter, which followed the generally reported trends.

Precycling Strategy in Suitable Voltage to Improve the Stability of Interfacial Film and Suppress the Decline of LiNi0.6Mn0.2Co0.2O2 Cathode at Elevated Temperatures.

Layered ternary oxide LiNixMnyCo1-x-yO2 is a promising cathode candidate for high-energy lithium-ion batteries (LIBs). However, the capacity of LIBs is significantly restricted by several factors, including the repeated dissolution-regeneration of the interfacial film at high temperatures, the dissolution of transition metals, and the increase of impedance. Herein, a new precycling strategy in suitable voltage scope at room temperature is proposed to construct a uniform, thermally stable, and insoluble cathode-electrolyte interface (CEI), which helps to maintain stable cycling performances at high temperatures. Specifically, after 5 precycles in the range of 3.85-4.3 V at room temperature, a CEI layer containing numerous inorganic components and oligomers is formed on the surface of LiNi0.6Mn0.2Co0.2O2. Subsequently, the harmful side reactions are effectively suppressed, endowing the cell with an excellent capacity retention of 84.67% after 50 cycles at 0.5C and 55 °C, much higher than that of 65.61% under the conventional film-forming process conditions. This work emphasizes the crucial role of the precycling strategy in regulating the characteristics of CEI layer on the surface of cathode electrode, opening up a new avenue for the high-temperature application of positive electrodes of LIBs.

Boosting acetaminophen degradation in water by peracetic acid activation: A novel approach using chestnut shell-derived biochar at varied pyrolysis temperatures

In this study, biochar derived from chestnut shells was synthesized through pyrolysis at varying temperatures from 300 °C to 900 °C. The study unveiled that the pyrolysis temperature is pivotal in defining the physical and chemical attributes of biochar, notably its adsorption capabilities and its role in activating peracetic acid (PAA) for the efficient removal of acetaminophen (APAP) from aquatic environments. Notably, the biochar processed at 900 °C, referred to as CN900, demonstrated an exceptional adsorption efficiency of 55.8 mg g−1, significantly outperforming its counterparts produced at lower temperatures (CN300, CN500, and CN700). This enhanced performance of CN900 is attributed to its increased surface area, improved micro-porosity, and a greater abundance of oxygen-containing functional groups, which are a consequence of the elevated pyrolysis temperature. These oxygen-rich functional groups, such as carbonyls, play a crucial role in facilitating the decomposition of the O–O bond in PAA, leading to the generation of reactive oxygen species (ROS) through electron transfer mechanisms. This investigation contributes to the development of sustainable and cost-effective materials for water purification, underscoring the potential of chestnut shell-derived biochar as an efficient adsorbent and catalyst for PAA activation, thereby offering a viable solution for environmental cleanup efforts.

Structural Evolution of Liquid Metals and Alloys.

Low-melting liquid metals are emerging as a new group of highly functional solvents due to their capability to dissolve and alloy various metals in their elemental state to form solutions as well as colloidal systems. Furthermore, these liquid metals can facilitate and catalyze multiple unique chemical reactions. Despite the intriguing science behind liquid metals and alloys, very little is known about their fundamental structures in the nanometric regime. To bridge this gap, this work employs small angle neutron scattering and molecular dynamics simulations, revealing that the most commonly used liquid metal solvents, EGaIn and Galinstan, are surprisingly structured with the formation of clusters ranging from 157Å to 15.7Å. Conversely, non-eutectic liquid metal alloys of GaSn or GaIn at low solute concentrations of 1, 2, and 5wt%, as well as pure Ga, do not exhibit these structures. Importantly, the eutectic alloys retain their structure even at elevated temperatures of 60 and 90°C, highlighting that they are not just simple homogeneous fluids consisting of individual atoms. Understanding the complex soft structure of liquid alloys will assist in comprehending complex phenomena occurring within these fluids and contribute to deriving reaction mechanisms in the realm of synthesis and liquid metal-based catalysis. This article is protected by copyright. All rights reserved.

Improving interfacial strength at room and elevated temperatures in ultrasonic welding of pure titanium: Interlayer-induced phase transformation and concentrated plastic deformation

Ultrasonic welding (USW) of Titanium (Ti) sheets presents several challenges, notably crack formation due to sliding friction. To overcome this problem, the present study applied USW to pure α-Ti sheets both with and without different interlayer metals (Al, Ni, and Fe). Al interlayer improved the strength at room temperature significantly to cause base metal fracture (1700 N) by inducing concentrated plastic deformation, facilitating bonding with Ti while minimizing damage. However, its strength decreased significantly at 150–300 °C, suggesting the limitation of using Al interlayer at elevated temperatures. Conversely, the Ni and Fe interlayers led to a two-phase strength development. This enhancement was due to β-phase transformation, which reduces the interfacial defects and generates a more pronounced β-stabilization effect. The Ni interlayer, which has a higher β-transus point (765 °C) and lower molybdenum equivalency, required a higher welding energy (1800 J) and longer diffusion time into Ti, resulting in a gradual increase in strength due to a slower β-Ti transformation. On the other hand, the Fe interlayer with a lower β-transus point relative to Ti (595 °C) achieved peak strength at a lower welding energy of 1200 J. Both Fe and Ni interlayers displayed only a slight decrease in strength (1500–1600 N) at 300 °C with base metal fracture, revealing better joint performance at higher temperatures. These insights suggest a strategical interlayer selection based on the operation temperature, where Al interlayers were advantageous for low-energy welding at room temperature application, Fe and Ni interlayers offer sufficient strength at elevated temperatures by facilitating the β-Ti formation.

Impact of simultaneous increase in CO2 and temperature on soil aggregates, associated organic carbon, and nutritional quality of rice–wheat grains

AbstractBackgroundFood and nutritional security remain a major thrust area in the under developed and developing countries. These problems are exaggerated by the unprecedented challenges of climate change.AimsThe aim of this study was to assess the impact of climate change on grain quality of wheat and rice genotypes as well as their effect on soil aggregate fractions and aggregate associated carbon.MethodologyIn the context, the present study was formulated by considering four predicted climate scenarios, namely, T0C0 (ambient condition), T0C1 (approx. 25% higher CO2), T1C0 (2°C higher temperature) and T1C1 (25% higher CO2 + 2°C higher temperature) and their impact on grain quality of wheat (HD2967, HD2733, DBW17, and HD3093) and rice (IR83376‐B‐B‐24‐2, IR84895‐B‐127‐CRA‐5‐1‐1, R Bhagwati, and IR64) genotypes as well as soil aggregate fractions and aggregate associated carbon.ResultsThe result revealed that T0C1 has a negative impact on grain nitrogen and protein content. On an average, nitrogen content in wheat and rice showed a decrease of about 15.55% (5.52%–25.32%) and 11.44% (3.33%–23.86%), respectively. Interestingly, the concurrent effect of elevated CO2 and temperature resulted in higher nitrogen and protein content as compared to other climate conditions. Further, P (P) content in the wheat and rice grains also improved under the elevated CO2 condition, whereas the content of potassium was not significantly influenced. Apart from major nutrients, micronutrients (Zn and Fe) were significantly influenced by climatic variables. The study revealed that grain Zn and Fe content of both the crops were reduced due to elevated CO2. The data on soil aggregate fractions revealed that elevated CO2 favors the formation of macro‐aggregate, whereas an increase in temperature favors micro‐aggregate fractions in the soil. Further, the elevation of CO2 also resulted in the accumulation of more carbon in the macro‐aggregates.ConclusionWe conclude that elevated CO2 and temperature cause specific changes in soil aggregate formation and grain nutrient quality. Based on molar ratio of P/Zn and P/Fe, we identified varieties of rice (IR83376‐B‐B‐24‐2) and wheat (HD2733) with higher bioavailability to address the nutritional security with changing climate in developing countries.

Investigation of the magnetic and structural properties in the non‐stoichiometric Heusler alloy Ni50Mn25+xSn25‐x; x = 13, 14

AbstractMemory shape magnetic alloys, especially Heusler alloys, are important materials in replacing conventional cooling with magnetic systems. In the present study off stoichiometric Heusler alloys with nominal composition Χ50Υ25+xΖ25‐x (X = Ni; Y = Mn; Z = Sn; x = 13, 14) were prepared by arc melting followed by thermal treatment. Structural properties were analyzed with X‐ray diffraction at room temperature (RT) and at elevated temperatures, above the martensite—austenite transition area, to determine the relevant crystallographic parameters and observe the transition. Martensite stabilization at RT appears to be a challenge, coexistence of martensite—austenite phases were observed and calculated for both 38–12 and 39–11 (16% and 12% austenite, respectively). Magnetization measurements versus temperature and field were recorded in the areas of interest where 1st order transitions were expected (355 K for x = 13 and 408 K for x = 14), and the magnetic entropy's changes (ΔSm) were determined [0.4 (J/kgK) for x = 13 and 0.3 J/(kgK) for x = 14; Hmax = 1 T]. The complex character of the magnetic properties and their dependence on Mn‐Sn ratio and on the distance between Mn atoms is discussed. The structure and the lattice parameters were determined using an anisotropic strain broadening model; stress and strain were detected in the structure due to crystal phase coexistence.

Boosted regeneration of coked SAPO-34 catalyst in MTO fluidized bed reactor by diluted air at elevated temperatures

SAPO-34 zeolite as an excellent catalyst for methanol-to-olefins (MTO) reaction suffers rapid deactivation by prevalent coking. Herein, regeneration of coked-SAPO-34 in a fluidized-bed reactor was successfully intensified by altering temperature (550–650 °C) and oxygen content (7–21 vol.%). Fresh, used, and regenerated catalysts were characterized by different methods to understand the correlation between regeneration conditions, coke content, and catalyst performance. The minor residual coke over the regenerated catalyst comprised active hydrocarbon pool intermediates (like naphthalene, benzaldehyde, phenol, and derivatives), which increased by decreasing regeneration temperature and promoted the selectivity to light olefins at earlier reaction times. The restored microporosity and lifetime of regenerated catalyst were superior by increasing temperature. However, higher attrition at 650 °C, as confirmed by SEM images, caused a partial weight loss of the catalyst and a slight decline in relative crystallinity, hence 600 °C was preferred with additional advantage of less energy consumption. Meanwhile, introducing lower oxygen not only moderated the coke oxidation rate but also enhanced the recovery of beneficial catalytic features for the MTO conversion. Consequently, considering an excellent regeneration as well as lower emission of CO2 detected in the flue gas, diluted air containing 14 vol.% O2 at 600 °C was suggested as the most promising method.

Two-Step Conversion of Metal and Metal Oxide Precursor Films to 2D Transition Metal Dichalcogenides and Heterostructures.

The widely studied class of two-dimensional (2D) materialsknown as transition metal dichalcogenides (TMDs) are now well-poised to be employed in real-world applications ranging from electronic logic and memory devices to gas and biological sensors. Several scalable thin film synthesis techniques have demonstrated nanoscale control of TMD material thickness, morphology, structure, and chemistry and correlated these properties with high-performing, application-specific device metrics. In this review, the particularly versatile two-step conversion (2SC) method of TMD film synthesis is highlighted. The 2SC technique relies on deposition of a solid metal or metal oxide precursor material, followed by a reaction with a chalcogen vapor at an elevated temperature, converting the precursor film to a crystalline TMD. Herein, the variables at each step of the 2SC process including the impact of the precursor film material and deposition technique, the influence of gas composition and temperature during conversion, as well as other factors controlling high-quality 2D TMD synthesis are considered. The specific advantages of the 2SC approach including deposition on diverse substrates, low-temperature processing, orientation control, and heterostructure synthesis, among others, are featured. Finally, emergent opportunities that take advantage of the 2SC approach are discussed to include next-generation electronics, sensing, and optoelectronic devices, as well as catalysis for energy-related applications.

Optimizing the lyophilization of Lumbricus terrestris erythrocruorin

Haemorrhagic shock is a leading cause of death worldwide. Blood transfusions can be used to treat patients suffering severe blood loss but donated red blood cells (RBCs) have several limitations that limit their availability and use. To solve the problems associated with donated RBCs, several acellular haemoglobin-based oxygen carriers (HBOCs) have been developed to restore the most important function of blood: oxygen transport. One promising HBOC is the naturally extracellular haemoglobin (i.e. erythrocruorin) of Lumbricus terrestris (LtEc). The goal of this study was to maximise the portability of LtEc by lyophilising it and then testing its stability at elevated temperatures. To prevent oxidation, several cryoprotectants were screened to determine the optimum formulation for lyophilisation that could minimise oxidation of the haem iron and maximise recovery. Furthermore, samples were also deoxygenated prior to storage to decrease auto-oxidation, while resuspension in a solution containing ascorbic acid was shown to partially reduce LtEc that had oxidised during storage (e.g. from 42% Fe3+ to 11% Fe3+). Analysis of the oxygen equilibria and size of the resuspended LtEc showed that the lyophilisation, storage, and resuspension processes did not affect the oxygen transport properties or the structure of the LtEc, even after 6 months of storage at 40 °C. Altogether, these efforts have yielded a shelf-stable LtEc powder that can be stored for long periods at high temperatures, but future animal studies will be necessary to prove that the resuspended product is a safe and effective oxygen transporter in vivo.

The role of Ti in mitigating thermal expansion of silica from molecular dynamics simulations

AbstractMolecular dynamics simulations are performed to investigate the structural response of titania silicate glass to temperature. The coefficient of thermal expansion is computed for two titania silicate glasses with 0 and 10 mol% titania content, the structures of which are presented in terms of radial and angular distributions. Revealed by the different changing rates of intertetrahedra bond angles and bond lengths with respect to the Ti and Si atoms, the glass structures tend to exhibit a nonvectorized expansion process at elevated temperatures, leading to inconsistent expansion rates of the structures in different scales. While the average length of TiO and Si‐O bonds both increases with temperature, the decrease in the coefficient of thermal expansion by the addition of Ti atoms is associated with the different expansion rate of tetrahedra. Arising from the gradual decrease in atomic overlapping, decrease in free volume inside the glass with temperature is also identified.

Electronic heat conductivity in a two-temperature state

Heat transport in solids is governed by two fundamental contributions, atomic and electronic. The electronic energy transport in transient excited states is a defining factor in the problem of ultrafast material irradiation. Here, we calculate the electronic heat conductivity at elevated electron temperatures up to 40,000 K. We apply the novel combined method of tight binding formalism to calculate the electron-phonon contribution to the electronic heat conductivity, and the linear response theory (in the single-pole Ritchie-Howie loss function approximation) for its electron-electron counterpart, implemented in the hybrid code XTANT-3. It allows us to evaluate the electronic heat conductivity in a wide range of materials – fcc metals: Al, Ca, Ni, Cu, Sr, Y, Zr, Rh, Pd, Ag, Ir, Pt, Au, and Pb; hcp metals: Mg, Sc, Ti, Co, Zn, Tc, Ru, Cd, Hf, Re, and Os; bcc metals: V, Cr, Fe, Nb, Mo, Ba, Ta, and W; other metals: Sn, Ga, In, Mn, Te, and Se; semimetal graphite; semiconductors – group IV: Si, Ge, and SiC; group III-V: AlAs, AlP, GaP, GaAs, and GaSb; oxides: ZnO, TiO2, and Cu2O; and others: PbI2, ZnS, and B4C.