Hot State Research Articles

Excited-State Decay and Photolysis of O-Nitrophenol before Proton Transfer. I: A Theoretical Investigation in the Microsolvated Atmospheric Environment.

As a potential source of the hydroxyl (OH) radical and nitrous acid (HONO), photolysis of o-nitrophenol (ONP) is of significant interest in both experimental and theoretical studies. In the atmospheric environment, the number of water molecules surrounding ONP changes with the humidity of the air, leading to an anisotropic chemical environment. This may have an impact on the photodynamics of ONP and provide a mechanism that differs from previously reported ones in the gas phase or in solution. Herein, the high-level MS-CASPT2//CASSCF method was performed to elucidate the excited-state decay and the generation of the OH radical for ONP before proton transfer in the microsolvated surrounding. We found that the varying number of water molecules affects the ground-state structures and alters the energy levels of nπ* and ππ* at the Franck-Condon (FC) region. Nevertheless, this is not the case for the excited-state minima, which exhibit very similar adiabatic excitation properties. In addition, the presence of water molecules also significantly influences the intersection structures since hydrogen bonds will hinder or alleviate the rotation or pyramidalization of the nitro (NO2) group. This will, in turn, change the excited-state relaxation mechanism of ONP. Finally, we speculated that the OH radical might be formed in the hot ground state of ONP in the microsolvated surrounding after exploring all possible electronic states.

Intramolecular benzene excimer formation in 13,14-diphenyldibenzo[b,j][4,7]phenanthroline.

13,14-diphenyldibenzo[b,j][4,7]phenanthroline (DBP3) in various solvents was studied by time-resolved fluorescence and fs transient absorption (fs-TA) spectroscopy. An intramolecular benzene excimer is demonstrated to form within DBP3; it exhibits strong redshifted emission with maximum at 540-640nm. "Intrinsic" fluorescence from DBP3 is dramatically quenched down to τ = 50-400fs in all the solvents studied. Fs-TA and time-resolved fluorescence spectra have proved that relaxed intramolecular benzene excimer is formed from S1 state via hot excimer state with three lifetime components: 50fs, ∼3.5ps, and ∼25ps, which are of the inertial (electronic) and diffusive parts of the relaxation due to solute-solvent interaction. Formation of triplet states via intersystem crossing was observed directly from the upper excited electronic states of DBP3.

Simulation of Inhomogeneous Refractive Index Fields Induced by Hot Tailored Forming Components

For effective quality control in hot forming applications, it is imperative that optical geometry reconstruction is conducted while the workpiece remains in its hot state to ensure the early detection of material distortion effects. This requirement is especially vital in the fabrication of hybrid bulk metal components with locally adapted properties, which are essential to address current challenges and demands on components, as well as to conserve resources. The utilization of hybrid materials results in differing thermal expansion coefficients, which significantly impact the shrinkage behavior of the component. Furthermore, the formation of these components involves exposure to high‐temperature gradients up to 1100 °C, causing the surrounding air to heat up and result in density variations. These variations generate an inhomogeneous refractive index field (IRIF), which substantially affects the surface reconstruction capabilities of optical measurement systems. Understanding the formation and dynamics of these refractive index fields is crucial to minimize uncertainties in optical measurements. This study aims to provide a comprehensive simulation model for the IRIF generated by hot‐forged tailored forming components. Utilizing this model, a priori information on the propagation characteristics of the IRIF can be obtained, thereby facilitating optimized positioning of the measurement system and minimizing reconstruction errors.

Highly Sensitive Two‐Dimensional Ruddlesden‐Popper Perovskites for Thermochromic Smart Windows

AbstractWith the growing demand for high‐performance smart windows, the discover of a class of thermochromic materials with reversible cycling and rapid response characteristics has become urgent. In this work, we have uncovered a two‐dimensional (2D) Ruddlesden‐Popper (RP) phase halide perovskite, (PMA)2MAPb2I7−xClx, where PMA=C6H5CH2NH3 and MA=CH3NH3, exhibiting exceptional reversible thermochromic properties. The 2D RP phase perovskite thin film features a low transition temperature (Tc=30 °C from the hydrated state to the hot state, along with a fast transition time of 40 s. Furthermore, the addition of 0.5 times excess MAI significantly enhances the visible light transmittance of the hydrated state. Characteristic hydration peaks in X‐ray diffraction patterns and O−H bond absorption peaks Fourier‐transform infrared spectra are observed in the thin film in its hydrated state, which disappear in the hot state, validating its reversible thermochromic properties. Additionally, a solar cell based on the thermochromic 2D RP phase thin film achieves a power conversion efficiency of 2.31 %, offering a promising solution for advanced smart window technologies.

Competing Nonadiabatic Relaxation Pathways for Near-UV Excited ortho-Nitrophenol in Aqueous Solution.

Nitrophenols are atmospheric pollutants found in brown carbon aerosols produced by biomass burning. Absorption of solar radiation by these nitrophenols contributes to atmospheric radiative forcing, but quantifying this climate impact requires better understanding of their photochemical pathways. Here, the photochemistry of near-UV (λ = 350 nm) excited ortho-nitrophenol in aqueous solution is investigated using transient absorption spectroscopy and time-resolved infrared spectroscopy over the fs to μs time scale to characterize the excited states, intermediates, and photoproducts. Interpretation of the transient spectroscopy data is supported by quantum chemical calculations using linear-response time-dependent density functional theory (LR-TDDFT). Our results indicate efficient nonradiative decay via an S1(ππ*)/S0 conical intersection leading to hot ground state ortho-nitrophenol which vibrationally cools in solution. A previously unreported minor pathway involves intersystem crossing near an S1(nπ*) minimum, with decay of the resulting triplet ortho-nitrophenol facilitated by deprotonation. These efficient relaxation pathways account for the low quantum yields of photodegradation.

Optimization of fluorinated phenyl azides as universal photocrosslinkers for semiconducting polymers

Fluorinated phenyl azides (FPA) enable photo-structuring of π-conjugated polymer films for electronic device applications. Despite their potential, FPAs have faced limitations regarding their crosslinking efficiency, and more importantly, their impact on critical semiconductor properties, such as charge-carrier mobility. Here, we report that azide photolysis and photocrosslinking can achieve unity quantum efficiencies for specific FPAs. This suggests preferential nitrene insertion into unactivated C‒H bonds over benzazirine and ketenimine reactions, which we attribute to rapid interconversion between the initially formed hot states. Furthermore, we establish a structure‒activity relationship for carrier mobility quenching. The binding affinity of FPA crosslinker to polymer π-stacks governs its propensity for mobility quenching in both PM6 and PBDB-T used as model conjugated polymers. This binding affinity can be suppressed by FPA ring substitution, but varies in a non-trivial way with π-stack order. Utilizing the optimal FPA, photocrosslinking enables the fabrication of morphology-stabilized, acceptor-infiltrated donor polymer networks (that is, PBDB-T: ITIC and PM6: Y6) for solar cells. Our findings demonstrate the exceptional potential of the FPA photochemistry and offer a promising approach to address the challenges of modelling realistic molecular interactions in complex polymer morphologies, moving beyond the limitations of Flory‒Huggins mean field theory.

Метод поєднання ливарного та термічного процесів виготовлення виливків із залізовуглецевих сплавів

With the help of innovations at an industrial enterprise, it is possible to increase labor efficiency and reduce the resource intensity of production. The relevance of the development of the technology of metal casting in sand molds, as the most common casting process, is justified by the fact that up to 80 % of the tonnage of castings is produced in such molds, including special types of casting in molds from sand materials. 60-70 % of the equipment capacities, areas, and personnel of foundry shops are attributed to molding processes, including mixing and rod production. Pollution "due to the mold" can reach up to 80%. A significant potential for the development of foundry mold technology is the improvement of the processes of casting metal into molds made of loose sand without a binding component, in particular, according to the Lost Foam Casting Process (LFC). The authors present the concept of improving the processes of casting metal into molds made of loose sand by the method of dual application of molding materials and give examples of such application. The use of loose molding sand for rapid cooling of the casting, including heat treatment, is able to strengthen its metal and reduce the duration of cooling of the casting in the mold, which leads to an increase in the productivity of foundries without increasing the number of furnace equipment and loose mold filler. The applied method of isothermal hardening (austempering) from the hot state of castings from iron-carbon alloys excludes heating with exposure for austenization of castings, which reduces the cost, time and energy consumption of obtaining products with a strengthened bainite structure, which, in fact, corresponds to the concept of realizing internal reserves as a foundry sand mold, and cast metal. Some foundry enterprises of the Vinnytsia region also use LFC or have concluded contracts, planning to reconstruct their shops for this ecological and economically beneficial foundry technology.

Polyurethane Based Smart Composite Fabric for Personal Thermal Management in Multi-Mode.

Textiles with thermal/moisture managing functions are of high interest. However, making the textile sensitive to the surrounding environment is still challenging. Herein, a multimodal smart fabric is developed by stitching together the Ag coated thermal-humidity sensitive thermoplastic polyurethane (Ag-THSPU) and the hybrid of polyvinylidene fluoride and polyurethane (PU-PVDF). The porous PU-PVDF layer is used for solar reflection, infrared emissivity, and water resistance. The Ag-THSPU layer is designed for regulating thermal reflection, sweat evaporation as well as convection. In cold and dry state, the Ag domains are densely packed covering the crystalline polyurethane matrix, featuring low water transmission (102.74gm-2·24h-1), high thermal reflection and 2.4°C warmer than with cotton fabric. In the hot and humid state, the THSPU layer is swollen by sweat and expands in area, resulting in the formation of micro-hook faces where the Ag domains spread apart to promote sweat evaporation (2084.88g/m-2·24h-1), thermal radiation and convection, offering 2.5°C cooler than with cotton fabric. The strategy reported here opens a new door for the development of adaptive textiles in demanding situations.

Aggregation promotes charge separation in fullerene-indacenodithiophene dyad

Fast photoinduced charge separation (CS) and long-lived charge-separated state (CSS) in small-molecules facilitate light-energy conversion, while simultaneous attainment of both remains challenging. Here we accomplish this through aggregation based on fullerene-indacenodithiophene dyads. Transient absorption spectroscopy reveals that, compared to solution, the CS time in aggregates is accelerated from 41.5 ps to 0.4 ps, and the CSS lifetime is prolonged from 311.4 ps to 40 μs, indicating that aggregation concomitantly promotes fast CS and long-lived CSS. Fast CS arises from the hot charge-transfer states dissociation, opening up additional resonant channels to free carriers (FCs); subsequently, charge recombination into intramolecular triplet CSS becomes favorable mediated by spin-uncorrelated FCs. Different from fullerene/indacenodithiophene blends, the unique CS mechanism in dyad aggregates reduces the long-lived CSS dependence on molecular order, resulting in a CSS lifetime 200 times longer than blends. This endows the dyad aggregates to exhibit both photoelectronic switch properties and superior photocatalytic capabilities.

Mitochondrial DNA-boosted dendritic cell-based nanovaccination triggers antitumor immunity in lung and pancreatic cancers

Low migratory dendritic cell (DC) levels pose a challenge in cancer immune surveillance, yet their impact on tumor immune status and immunotherapy responses remains unclear. We present clinical evidence linking reduced migratory DC levels to immune-cold tumor status, resulting in poor patient outcomes. To address this, we develop an autologous DC-based nanovaccination strategy using patient-derived organoid or cancer cell lysate-pulsed cationic nanoparticles (cNPs) to load immunogenic DC-derived microvesicles (cNPcancer cell@MVDC). This approach transforms immune-cold tumors, increases migratory DCs, activates Tcells and natural killer cells, reduces tumor growth, and enhances survival in orthotopic pancreatic and lung cancer models, surpassing conventional methods. Invivo imaging reveals superior cNPcancer cell@MVDC accumulation in tumors and lymph nodes, promoting immune cell infiltration. Mechanistically, cNPs enrich mitochondrial DNA, enhancing cGAS-STING-mediated DC activation and migration. Our strategy shifts cold tumors to a hot state, enhancing antitumor immunity for potential personalized cancer treatments.

Горячее деформирование корпусных заготовок в изотермических условиях

Core operations with hollow products, having a periodically changing internal profile, consists in the final machining of press forgings. However, at the same time, metal rejects are high, and despite the high quality of the products obtained, their mechanical characteristics do not always meet the requirements of functioning. For the equipment units, when subjected to heavy loads, the parts are usually made of high-strength materials. Due to the complexity of the work on a workpieces made of high-strength alloys, operations are carried out with heating of the deformed zone of the in-process part or with a total heating. The use of slow deformation in the hot state under certain speed conditions is promising. The process of the internal pattern formation for hollow shells made of titanium alloy VT6 is viewed. These products are mainly used as various airframes and are made using special methods of mechanical engineering. Due to the use of high-strength billet materials, there are difficulties with the mechanization of the production methods. The article evaluates force conditions for generation of geometry on the shells based on CAE modeling. The simulation was performed in the deform complex. The focus of the research was on the assessment of deformation forces and stress intensities. The influence of deformation ratio, strain rates, punch geometry on the strength of the process and stress intensity has been revealed. A regression equation to estimate the forces of the process is deduced. Recommendations on the design of fillets forming operations have been obtained. Deformation modes aimed at achieving rational power modes, respectively, loads on the tool, which indirectly affects its durability, as well as the stress condition in the product, have been found.

О классификации и обусловленности факторов самонагревания углепородного отвала Донбасса

A classification of self-heating factors of the Donbass coal dump and a schematic model of their interrelation-ships are proposed in relation to the analysis of search criteria and signs of a man-made coal-type object suit-able for long-term heat extraction. The presented classification makes it possible to distinguish between simple, complex and particularly complex, spatial, temporal and spatio-temporal, external and internal, accelerating and slowing factors of self-heating of dump masses, as well as to systematize the specified factors by the levels of their influence on the thermal state of coal rock dump. The classification is useful in establishing simultaneously acting dominant self-heating factors inherent in the warm, burning and extremely hot states of the coal dump. In the course of study, it was established that factors of self-heating are determined by the mining-geological, mining-technical and natural-climatic conditions of mining and also often mutually agreed. The greatest degree of mutual agreement is possessed by meso-level factors, which include the vital activity of thionic bacteria, oxidative reactions and unsolved heat of coal mining waste. The presented schematic model of the relationships and relationships of the self-heating factors will be useful for analyzing the thermal state of the dump and predicting the dynamics of the geological and ecological situation around the dump, potentially suitable for long-term heat extraction.

Low-loss vanadium dioxide-enabled mmWave tunable reflective electromagnetic surface with complementary unit cells for wave manipulation

This study presents a novel implementation of vanadium dioxide (VO2) phase change material in an electromagnetic (EM) surface with beam steering capabilities. For the first time, we present the design, fabrication, and measurement of a globally actuated, VO2-based beamforming reflective EM surface. We propose a design featuring complementary unit cells that enable beam steering with a single excitation, marking a pioneering use of low-loss VO2 in creating a complementary EM surface for the mmWave band. The unit cells incorporating VO2 exhibit low-loss characteristics, with −0.92 and −1.9 dB in the hot state and −0.49 and −0.25 dB in the cold state, respectively. We incorporate both positive and negative phase variants alongside two temperature-independent phase unit cells. The complementary design enables us to utilize two beam operating states, effectively exploiting the otherwise unused cold state. We experimentally demonstrated beamforming at ±5° and ±10° from the broadside. In the case of ±10°, the measured gains at 35 GHz in the cold and hot states were 19.4 and 20.3 dB, respectively, which aligned well with the simulated gains of 20.9 and 21.5 dB. Manipulation of the electromagnetic wave direction with a single excitation has the potential for imaging, sensing, and communication applications. The complementary unit cell design methodology can be further adapted for mmWave beamforming, absorbing, and cloaking reconfigurable EM surfaces. Furthermore, the use of VO2 can be extended up to sub-THz frequencies due to the wideband, low-loss characteristics compared with conventional reconfigurable devices, such as PIN diodes or MEMS switches.

Influence of aerodynamic valve structural parameters on detonation initiation and back pressure characteristics of air-breathing pulse detonation engine

In order to enhance the stability of detonation initiation in air-breathing pulse detonation engines (APDE), while simultaneously mitigating the non-stationary back pressure disturbance due to the huge pressure gain in the APDE, a central blunt body aerodynamic valve (aero-valve) was developed and tested with a single-tube pulse detonation combustor (PDC). The detonation initiation and back pressure characteristics of PDC were then discussed. In order to reveal the influence of the aero-valve's structural parameters on the cold-state filling, detonation initiation, and back pressure characteristics of PDC, numerical simulations were carried out based on the experimental setup. The numerical results indicated that the cold-state flow characteristics within the aero-valve was predominantly influenced by the inner diameter of the aero-valve shell (Das), while the cold-state flow inside the combustor was primarily dominated by the axial distance from the thrust wall to the aero-valve shell (Lx) and the inner diameter of the aero-valve outlet (dout). And dout has a larger impact on the cold-state flow inside the combustor. During the hot state, reducing Lx or dout is beneficial for both the generation of detonation and the suppression of back pressure, with the most significant gain effect coming from decreasing dout. The optimal combination scheme for the aero-valve is identified as Das/R = 4.5, Lx/R = 0.25 and dout/R = 0.7, where R is the detonation combustor radius. The PDC equipped with this optimized aero-valve not only has better detonation initiation characteristics, but also a smaller pressure oscillation ratio.

Deciphering yield modification of hadron-triggered semi-inclusive recoil jets in heavy-ion collisions

In relativistic heavy-ion collisions, a hot and dense state of matter, called the Quark-Gluon Plasma (QGP), is produced. Semi-inclusive jets recoiling from trigger hadrons of high transverse momenta (pT) can serve as an effective probe of the QGP properties, as they are expected to experience jet quenching when traversing the QGP. Recent experimental results on the ratio of recoil jet yields normalized by the trigger counts in heavy-ion collisions to that in p+p collisions (IAA) pose an unexpected challenge in its interpretation. It is observed that IAA rises with the jet pT and possibly exceeds unity at high pT, while traditionally it is expected that jet quenching would lead to IAA<1. To address this challenge, we utilize the Linear Boltzmann Transport (LBT) model to simulate jet transport in the QGP, and study the effect of jet quenching for high-pT triggers and recoil jets separately on IAA. We find that the quenching of the colored triggers alone is responsible for the rising trend and larger-than-unity value observed experimentally.

Reconfigurable intelligent surface and switchable electromagnetic interference shield based on dynamically adjustable composite film of cellulose nanofibers and VO2 nanoparticles

The emerging fields of 5G and 6G telecommunication networks, Internet of Things, and artificial intelligence have intensified the demand for green nanostructured materials with adjustable and intelligent features that respond to external stimuli. By leveraging the insulator-to-metal transition of VO2 nanoparticles, responsive composite films were developed by integrating these nanoparticles within a biopolymeric network of cationic cellulose nanofibers (CNF+). These films exhibit a reversible change in GHz permittivity upon exposure to thermal or optical stimuli, facilitating dynamic control of their electrical properties. The layered structure of the films further enhances their robustness, featuring a VO2 nanoparticle core encased within CNF+ layers. This design not only strengthens the structure but also significantly boosts light-induced conductivity, particularly in layered variant, underscoring its potential in optoelectronic applications. Simulation studies reveal that the nonuniform, reconfigurable intelligent surface (RIS) of the developed mixed film adeptly manipulates incident electromagnetic waves, making it suitable for 5G/6G wireless signals. Conversely, the layered film serves as a switchable electromagnetic interference (EMI) shield, demonstrating notable differences in shielding efficiency between its hot and cold states. Consequently, CNF+/VO2 composite films designed in this work emerge as a versatile, adaptable platform for intelligent electronics, particularly in the realm of 5G/6G wireless communications.

Thermal deformation behavior and microstructural evolution of the rapidly-solidified Al–Zn–Mg–Cu alloy in hot isostatic pressing state

Isothermal uniaxial compression experiments were performed in the temperature range of 340–460 °C and the deformation rate range of 0.001–1 s−1 to analyze the hot deformation behavior of the rapidly-solidified Al–Zn–Mg–Cu alloy in hot isostatic pressing state. A strain-compensated constitutive model was established to determine the flow stress in the alloy (based on the true stress-true strain data), and the average activation energy for the hot deformation was calculated as Q = ∼146 kJ/mol. The proposed model exhibited a high predictability with an average absolute relative error of 2.68% and a correlation coefficient of 0.99724. The processing map revealed that the alloy in the hot isostatic pressed state offers better workability than the spray-deposited alloy, and its optimal workable ranges at a strain of 0.78 are 370–390 °C/0.004–0.01 s−1 and 400–460 °C/0.005–0.06 s−1, respectively. The microstructural evolution shows that the main dynamic softening mechanism changes from dynamic recovery to continuous dynamic recrystallization with the increase in temperature and the decrease in strain rate.

A large population of neutron star low-mass X-ray binaries with long outburst recurrence time?

ABSTRACT Low-mass X-ray binaries (LMXBs) with neutron stars show quite different features that depend on the rate of mass transfer from the donor star. With a high transfer rate, the Z sources are in a persistent soft spectral state, and with a moderate transfer rate the transient Atoll sources have outburst cycles like the black hole X-ray binaries. The observations document very long outburst recurrence times for quite a number of sources. We follow with our computations the evolution of the accretion disc until the onset of the ionization instability. For sources with a low mass transfer rate, the accumulation of matter in the disc is essentially reduced due to the continuous evaporation of matter from the disc to the coronal flow. Different mass transfer rates result in nearly the same amount of matter accumulated for the outburst, which means that the outburst properties are similar for sources with short outburst cycles and sources with long outburst cycles, contrary to some expectations. Then, for systems with long recurrence time, less sources will be detected and the total population of LMXBs could be larger than it appears. This would relieve the apparent problem that the observed number of LMXBs as progenitors of millisecond pulsars (MSPs) is too small compared to the number of MSPs. Concerning the few quasi-persistent sources with year-long soft states, we argue that these states are not outbursts, but quasi-stationary hot states as in Z sources.

Engineering Metal Halide Perovskite Nanocrystals with BODIPY Dyes for Photosensitization and Photocatalytic Applications.

The sensitization of surface-anchored organic dyes on semiconductor nanocrystals through energy transfer mechanisms has received increasing attention owing to their potential applications in photodynamic therapy, photocatalysis, and photon upconversion. Here, we investigate the sensitization mechanisms through visible-light excitation of two nanohybrids based on CsPbBr3 perovskite nanocrystals (NC) functionalized with borondipyrromethene (BODIPY) dyes, specifically 8-(4-carboxyphenyl)-1,3,5,7-tetramethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BDP) and 8-(4-carboxyphenyl)-2,6-diiodo-1,3,5,7-tetramethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (I2-BDP), named as NC@BDP and NC@I2-BDP, respectively. The ability of I2-BDP dyes to extract hot hole carriers from the perovskite nanocrystals is comprehensively investigated by combining steady-state and time-resolved fluorescence as well as femtosecond transient absorption spectroscopy with spectroelectrochemistry and quantum chemical theoretical calculations, which together provide a complete overview of the phenomena that take place in the nanohybrid. Förster resonance energy transfer (FRET) dominates (82%) the photosensitization of the singlet excited state of BDP in the NC@BDP nanohybrid with a rate constant of 3.8 ± 0.2 × 1010 s-1, while charge transfer (64%) mediated by an ultrafast charge transfer rate constant of 1.00 ± 0.08 × 1012 s-1 from hot states and hole transfer from the band edge is found to be mainly responsible for the photosensitization of the triplet excited state of I2-BDP in the NC@I2-BDP nanohybrid. These findings suggest that the NC@I2-BDP nanohybrid is a unique energy transfer photocatalyst for oxidizing α-terpinene to ascaridole through singlet oxygen formation.

Ізотермічне гартування залізовуглецевих сплавів, суміщене з їх виливанням

Isothermal hardening (Austempering) of iron-based alloys with medium and high carbon content, which creates a metallic structure called bainite, is used to increase the strength and impact toughness of the metal. The parts are heated to a temperature approximately 200-300 °C below the solidification temperature of the metal, then cooled (hardened) fairly quickly to the temperature of the beginning of the bainite transformation, avoiding the martensitic transformation, and kept for a time sufficient to obtain the given bainite microstructure. IG is particularly advantageous for castings from high-strength cast iron (HC), adding to the high foundry performance of the growth of the mechanical characteristics of this alloy to the level of steel strength at a lower cost, density and energy consumption of HC casting compared to steel. The article examines methods of heat treatment of castings removed in a hot austenitic state from a sand mold, as a type of heat treatment of iron-carbon alloys combined with their casting. For this, casting according to gasification models was used, in which, due to the high fluidity of the dry sand of the casting mold, it is not difficult to remove hot castings from the mold for tempering. A number of IG methods previously patented by the FTIMS Institute of the National Academy of Sciences of the Russian Academy of Sciences have been supplemented by a new method of such hardening in a dosed amount of water, taking into account the effect of its film boiling. The new method includes the calculation of the optimal mass of quenching liquid - water with the aim of heating this mass of water to its boiling point at the time of cooling of the casting to the given temperature of the bainite transformation of the metal. The method saves the quenching liquid, simplifies the control of the duration of cooling, during which it allows the transportation of castings between the foundry and heat-treatment sections, which, in general, saves time, energy resources and the area of the workshop for obtaining heat-treated castings. Keywords: isothermal hardening, heat treatment, castings, austenite, lost foam casting.