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With the advancement of non-classical light sources such as single-photon and entangled-photon sources, innovative microscopy based on quantum principles has been proposed for traditional microscopy. This paper introduces the experimental demonstration of a quantum polarization microscopic technique that incorporates a quantum-entangled photon source. Although the point that employs the variation in polarization angle due to reflection or transmission at the sample is similar to classical polarization microscopy, the method for constructing the image contrast is significantly different. The image contrast is constructed by the coincidence count of signal and idler photons. In the case that the coincidence count is recorded from both the signal and idler photons, the photon statistics resemble a thermal state, similar to the blackbody radiation, but with a significantly higher peak intensity in the second-order autocorrelation function at zero delay that is derived from the coincidence count, while, when the coincidence count is taken from either the signal or idler photon only, although the photon state exhibits a thermal state again, the photon statistics become more dispersive and result in a lower peak intensity of the autocorrelation function. These different thermal states can be switched by slightly changing the photon polarization, which is suddenly aroused within a narrow range of the analyzer angle. The autocorrelation function g2(0) at the thermal state exhibits a sensitivity that is three times higher compared to the classical coincidence count rate, and this concept can be effectively utilized to enhance the contrast of the image. One of the key achievements of our proposed method is ensuring a low power of illumination (in the order of Pico-joules) for constructing the image. In addition, the robustness without any precise setup is also favorable for practical use. This polarization microscopic technique can provide a superior imaging technique compared to the classical method, opening a new frontier for research in material sciences, biology, and other fields requiring high-resolution imaging. [ABSTRACT FROM AUTHOR]

We performed computer simulations of the screw piercing of titanium-nickelide shells in two- and four-high mills. On the basis of the accumulated numerical results, we compute the parameters of the stress-strain and thermal states of the shells. The distributions of levels of the accumulated strain and the normalized mean stress show that a more homogeneous stress-strain state and a lower hazard of fracture of the shells are detected in the case of four-high piercing. The analysis of the temperature distribution shows that, in the case of four-high piercing, the obtained temperature state is more favorable for guaranteeing higher levels of plasticity of the materials of pierced shells. [ABSTRACT FROM AUTHOR]

In modern quantum information, the associated protocols highly rely upon qubit-qutrit systems which offer enhanced robustness to decoherence and greater encoding capabilities, essential for fault-tolerant quantum computing and cryptography. This study investigates the dynamic behavior of quantum coherence and entanglement in a qubit-qutrit system subjected to diverse interactions and exposed to external magnetic and classical fields influenced by Ornstein-Uhlenbeck (OU)-Static mixed noise. Various system parameters are explored to discern their impact on quantum correlations over time. The dynamics characterized by spin-coupling reveal an initial entangled state, with coherence and negativity exhibiting finite values. However, the entanglement diminishes over time, accompanied by damped oscillations, indicative of coherent dynamics. Contrastingly, the magnetic field demonstrates a diminishing trajectory in coherence and negativity with increasing values, leading to complete vanishing at critical thresholds. Temperature variations display a declining trend in coherence and negativity as temperature rises, highlighting its role as a dampening factor disrupting quantum correlations. The variations in state noise disorder parameters reveal enhanced preservation and reduced oscillations as the noise disorder parameter decreases, emphasizing its crucial role in shaping quantum correlations. In addition, we observe the dynamics to be more fluctuating with increasing field coupling strength. Our findings show that the hybrid setup presented here gives completely varying traits compared to the individual configuration of qubit-qutrit systems, static noise, and OU noise studied previously. The proposed framework can serve as a prototype for studying quantum systems beyond two-level qubits, providing a more comprehensive understanding of multi-level quantum states under realistic noise. [ABSTRACT FROM AUTHOR]

The conformal scalar propagator as an explicit function of the Schwarzschild black-hole space-time has been established in the preceding three projects. The present project examines the precise relation which that propagator has to the amplitude the Schwarzschild black hole emit a scalar particle in a particular mode of positive energy. It is thereby established that the effect of infinite time-dilation on the event horizon results in both, the thermal radiation in the background of a static exterior space-time geometry and the detraction from thermality if energy-conservation is properly imposed as a constraint on scalar propagation. The derivation of the latter signifies an equivalent approach to the result of Parikh and Wilczek from the semi-classical perspective of the distant observer. From that perspective for that matter, Hawking radiation emerges in both contexts as the exclusive consequence of infinite time-dilation on the event horizon. These results are consistent with Hawking radiation as the exclusive consequence of the causal structure of the Schwarzschild black-hole space-time both, in a static exterior geometry and in such dynamical exterior geometry as energy-conservation signifies. The extension of the thermal case to other spin-fields and black-hole geometries is discussed. [ABSTRACT FROM AUTHOR]

This paper explores the behaviour of the normalized emission spectrum within the confines of the atom-photon-magnon regime at its dispersive limit, with a focus on its dependency on various parameters and initial conditions. The investigation reveals several significant findings. Firstly, regarding the mixing angle and detuning, minimal variation in the spectrum is observed with small detuning values, although the influence of the mixing angle becomes more pronounced for the initial squeezed coherent and initial binomial states, particularly notable in the case of the squeezed coherent state. Secondly, concerning the initial state strength, an increase in strength results in a gradual decrease in the spectrum across all states except the binomial state, which finally experiences an increase. However, the squeezed coherent state displays a gradual decay without reaching zero, whereas the thermal state decays completely. Lastly, concerning magnon-cavity coupling, stronger coupling between magnon-and cavity causes a shift in the spectrum towards higher positive detuning, with a more pronounced shift observed in the squeezed coherent state compared to other states. [ABSTRACT FROM AUTHOR]

This paper presents the results of the development of stabilization measures aimed at the removal of zinc with the products of melting and accumulation of titanium in the hearth of a blast furnace. The relevance of the development and use in practice of such measures is due to the unstable fuel and raw materials conditions for the production of cast iron, when their stabilization is a complex and difficult task, as well as the need to extend the campaign of blast furnaces during the overhaul period. The negative effect of zinc oxides on the condition of the blast furnace shaft lining, accompanied by slab formation, and the overconsumption of specific coke consumption, which occurs when zinc circulates in the volume of the blast furnace, require measures to remove zinc from the smelting products. The article proposes such measures, which consist of flushing according to the proposed schedule during the operation of the blast furnace at planned blowing parameters and with the provision of the necessary thermal reserve. In order to lengthen the campaign of a blast furnace, one of the most common methods for protecting the hearth lining is the periodic introduction of titanium‐containing materials into the charge of blast furnaces. The entry of titanium oxides into the furnace, as a rule, is ensured by the use of concentrate or specially prepared ilmenite briquettes with a high titanium content as part of the sinter charge, which can be introduced directly into the composition of the blast furnace charge. The article analyzes the experience of using titanium‐containing materials as part of a blast furnace charge and formulates measures to intensify skull formation in the hearth. [ABSTRACT FROM AUTHOR]

The compositional and thermal state of Earths mantle provides critical constraints on the origin, evolution, and dynamics of Earth. However, the chemical composition and thermal structure of the lower mantle are still poorly understood. Particularly, the nature and origin of the two large low-shear-velocity provinces (LLSVPs) in the lowermost mantle observed from seismological studies are still debated. In this study, we inverted for the 3D chemical composition and thermal state of the lower mantle based on seismic tomography and mineral elasticity data by employing a Markov chain Monte Carlo framework. The results show a silica-enriched lower mantle with a Mg/Si ratio less than ~1.16, lower than that of the pyrolitic upper mantle (Mg/Si = 1.3). The lateral temperature distributions can be described by a Gaussian distribution with a standard deviation (SD) of 120 to 140 K at 800 to 1,600 km and the SD increases to 250 K at 2,200 km depth. However, the lateral distribution in the lowermost mantle does not follow the Gaussian distribution. We found that the velocity heterogeneities in the upper lower mantle mainly result from thermal anomalies, while those in the lowermost mantle mainly result from compositional or phase variations. The LLSVPs have higher density at the base and lower density above the depth of ~2,700 km than the ambient mantle, respectively. The LLSVPs are found to have ~500 K higher temperature, higher Bridgmanite and iron content than the ambient mantle, supporting the hypothesis that the LLSVPs may originate from an ancient basal magma ocean formed in Earths early history.

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Abstract This paper presents the results of the development of stabilization measures aimed at the removal of zinc with the products of melting and accumulation of titanium in the hearth of a blast furnace. The relevance of the development and use in practice of such measures is due to the unstable fuel and raw materials conditions for the production of cast iron, when their stabilization is a complex and difficult task, as well as the need to extend the campaign of blast furnaces during the overhaul period. The negative effect of zinc oxides on the condition of the blast furnace shaft lining, accompanied by slab formation, and the overconsumption of specific coke consumption, which occurs when zinc circulates in the volume of the blast furnace, require measures to remove zinc from the smelting products. The article proposes such measures, which consist of flushing according to the proposed schedule during the operation of the blast furnace at planned blowing parameters and with the provision of the necessary thermal reserve. In order to lengthen the campaign of a blast furnace, one of the most common methods for protecting the hearth lining is the periodic introduction of titanium‐containing materials into the charge of blast furnaces. The entry of titanium oxides into the furnace, as a rule, is ensured by the use of concentrate or specially prepared ilmenite briquettes with a high titanium content as part of the sinter charge, which can be introduced directly into the composition of the blast furnace charge. The article analyzes the experience of using titanium‐containing materials as part of a blast furnace charge and formulates measures to intensify skull formation in the hearth.

In the period of shelling of energy facilities of Ukraine by the enemy, emergency damage to the working blades of the rotors and stators of the turbines occurs. Papers related to the determination of the thermal and stress-strain states of power equipment elements, which have a significant impact in the conditions of the CHPP operation after its damage, are quite relevant. The authors determine the thermal and stress-strain states that occur after damage to the medium-pressure rotor (MPR) of the T-100/120-130 power unit of the CHPP under emergency damage conditions. When calculating the thermal and stress-strain states of the MPR, taking into account the technical audit data on damage, a geometric model of the MPR was created, which takes into account all existing emergency damage and changes in the frame compared to the design one. When starting from the cold state of the T-100/120-130 turbine MPR, the maximum intensities of conditional elastic stresses at the moment of time of 16800 s in the zone of the seal groove behind the third non-regulated stage of the MPR are equal to σі=127 MPa, and in the zone of the axial opening – σі=125 MPa. The maximum intensities of conditional elastic stresses at the moment of time of 18000 s in the zone of the seal groove behind the third non-regulated stage of MPR are equal to σі=123 MPa, and in the zone of the axial hole – σі=125 MPa when starting from an uncooled state. The maximum intensities of conditional elastic stresses during start-ups from the hot state of the T-100/120-130 turbine MPR at the moment of time of 6400 s (3000 rpm) in the zone of the first unregulated stage in the seal groove according to the MPR stage are equal to σі=201 MPa, and in zone of the axial opening they are equal to σі=161 MPa. The intensities of conditional elastic stresses at the moment of time of 7000 s (3000 rpm) in the zone of the first unregulated stage in the seal groove according to the degree of MPR σі=168 MPa and in the zone of the axial hole σі=161 MPa also are significant.

The paper is devoted to the study of temperature and stress distribution in the medium-pressure rotor of the K-200-130 turbine, which are of considerable interest when predicting the durability of this equipment and extending its operation beyond the service life. A geometric model of the most loaded part of the rotor – from the middle of the shaft neck in the thrust bearing area to the 5th stage disc – was developed. The study of the thermal and stress-strain state of the rotor during start-up from a cold state was performed in a two-dimensional formulation using the finite element method. The non-stationary problem of heat conduction during start-up was solved. The obtained results indicate a fairly uniform thermal state during variable operating conditions. The largest temperature gradient (1200–2200 K/m) is observed at the time points from the rotor push to the synchronization of the turbine generator with the power system. After the turbine generator is loaded with up to 30 MW of electric power, a decrease in the temperature field irregularity and its gradual stabilization are observed. It was found that when operating at the nominal steam parameters, the maximum metal temperature is 508 °C in the region of the control stage and decreases when the distance from it increases. The stress-strain state of the rotor was evaluated taking into account the unevenness of temperature fields during start-up, stresses from thermal expansion, and centrifugal forces. The highest stresses are characteristic of the moment when the turbine comes to idle in the area of thermal compensation grooves of the rotor and the control gate and amount to 440–472 MPa. It is noted that these areas are the most likely zones of ring crack nucleation during turbine start-up operations. Subsequently, the stress level gradually decreases as the turbine unit reaches its rated power. It has been established that the most stressed area of the rotor during stationary operation is the area of the axial bore under the control stage and its diaphragm seal (121–134 MPa)

With the advancement of non-classical light sources such as single-photon and entangled-photon sources, innovative microscopy based on quantum principles has been proposed for traditional microscopy. This paper introduces the experimental demonstration of a quantum polarization microscopic technique that incorporates a quantum-entangled photon source. Although the point that employs the variation in polarization angle due to reflection or transmission at the sample is similar to classical polarization microscopy, the method for constructing the image contrast is significantly different. The image contrast is constructed by the coincidence count of signal and idler photons. In the case that the coincidence count is recorded from both the signal and idler photons, the photon statistics resemble a thermal state, similar to the blackbody radiation, but with a significantly higher peak intensity in the second-order autocorrelation function at zero delay that is derived from the coincidence count, while, when the coincidence count is taken from either the signal or idler photon only, although the photon state exhibits a thermal state again, the photon statistics become more dispersive and result in a lower peak intensity of the autocorrelation function. These different thermal states can be switched by slightly changing the photon polarization, which is suddenly aroused within a narrow range of the analyzer angle. The autocorrelation function g2(0) at the thermal state exhibits a sensitivity that is three times higher compared to the classical coincidence count rate, and this concept can be effectively utilized to enhance the contrast of the image. One of the key achievements of our proposed method is ensuring a low power of illumination (in the order of Pico-joules) for constructing the image. In addition, the robustness without any precise setup is also favorable for practical use. This polarization microscopic technique can provide a superior imaging technique compared to the classical method, opening a new frontier for research in material sciences, biology, and other fields requiring high-resolution imaging.

Determining the composition of Earth's lower mantle, which constitutes almost half of its total volume, has been a central goal in the Earth sciences for more than a century given the constraints it places on Earth's origin and evolution. However, whether the major element chemistry of the lower mantle, in the form of, e.g., Mg/Si ratio, is similar to or different from the upper mantle remains debated. Here we use a multidisciplinary approach to address the question of the composition of Earth's lower mantle and, in turn, that of bulk silicate Earth (crust and mantle) by considering the evidence provided by geochemistry, geophysics, mineral physics, and geodynamics. Geochemical and geodynamical evidence largely agrees, indicating a lower-mantle molar Mg/Si of ≥1.12 (≥1.15 for bulk silicate Earth), consistent with the rock record and accumulating evidence for whole-mantle stirring. However, mineral physics–informed profiles of seismic properties, based on a lower mantle made of bridgmanite and ferropericlase, point to Mg/Si ∼ 0.9–1.0 when compared with radial seismic reference models. This highlights the importance of considering the presence of additional minerals (e.g., calcium-perovskite and stishovite) and possibly suggests a lower mantle varying compositionally with depth. In closing, we discuss how we can improve our understanding of lower-mantle and bulk silicate Earth composition, including its impact on the light element budget of the core. The chemical composition of Earth's lower mantle is indispensable for understanding its origin and evolution. Earth's lower-mantle composition is reviewed from an integrated mineral physics, geophysical, geochemical, and geodynamical perspective. A lower-mantle molar Mg/Si of ≥1.12 is favored but not unique. New experiments investigating compositional effects of bridgmanite and ferropericlase elasticity are needed to further our insight. [ABSTRACT FROM AUTHOR]

Currently, when large-scale military actions are taking place on the territory of Ukraine, the inclusion of the domestic energy system in the European one is a reliable component of providing electricity to the country's energy market. However, according to experts, uninterrupted and safe operation of nuclear power plants is still considered a prerequisite for the stable operation of the energy sector of Ukraine. The purpose of the paper is to assess the damageability and individual resource of the rotor of high-pressure cylinder (HPC) of the K-1000-60/3000 turbine power unit of the LMZ after damage to the blades in order to prolong the operation of the power unit in the conditions of a stressed state of the power system. One of the most effective ways to partially solve the problem of replacement of generating capacities is to extend the operating periods of NPP power units after the end of the project operating period, provided that nuclear and radiation safety standards are met. The review of the previously established service life of the energy equipment of NPP power units involves the assessment of the residual resource of the energy equipment in accordance with the regulatory documents. After the accidental damage of the blades of the last stage of the HPC rotor of the K-1000-60/3000 turbine power unit of the LMZ, there was a need to study the cyclic and static damage, the individual residual resource of the HPC rotor. In the process of achieving the goal, studies were carried out for three design options: the original option (five stages of the HPC rotor), the option without the blades of the last stage and the option without the fifth stage (with four first stages). The calculation of the resource indicators of the rotor in the execution of the HPC without blades of the 5th stage shows that the static damage accumulated in the main metal is 52%, the cyclic damage is 5% when applying the standard strength reserves for the number of cycles and for deformations at the level of nN=10 and nε=1.5 according to the recommendations of SOU-N MEV 40.1-21677681-52:2011. Thus, the total damage to the base metal is 57%, which sets the residual resource of the HPC rotor at the level of 88.4 thousand hours. The calculation of the resource indicators of the rotor in the execution of the HPC without entire 5th stage shows that the static damage accumulated in the base metal is 52%, the cyclic damage is 6% when applying the standard strength reserves for the number of cycles and deformations at the above-mentioned level. The total damage to the base metal is 58%, which determines the residual resource of the HPC rotor at the level of 85.6 thousand hours.

We extend the numerical-analytic approach approved for the problems of heat conduction for thermosensitive bodies, which are in perfect contact, to the case of similar nonlinear problems formulated for the case of friction heating. The proposed approach is based on the application of the Kirchhoff integral transform, a version of the method of successive approximations, the Laplace integral transform, and its inversion by the Prudnikov formula. By using this approach, we solve the problems for a tribosystem formed by either contacting thermosensitive half spaces or a half space and a layer subjected to convective-radiative heat exchange. We consider the case of an arbitrary character of changes in the thermal characteristics. On the basis of the constructed solutions, we analyze the thermal state of the corresponding thermosensitive piecewise homogeneous structures under the conditions of friction heating. [ABSTRACT FROM AUTHOR]

In the present paper, we have studied the higher as well as the lower-order nonclassicalities of photon-added-then-subtracted and photon-subtracted-then-added thermal and even coherent states. Different criteria such as Mandel's function ( Q M (l) ), higher-order antibunching ( d h (l - 1) ), sub-Poissonian photon statistics ( D h (l - 1) ), higher-order squeezing ( S (l) ), Husimi function (Q), Agarwal–Tara criteria ( A 3 ) and Klyshko's condition (B(m)) are used to witness the nonclassical feature of these states. Many of these conditions established that the considered states are highly nonclassical. It is also realized that the non-Gaussian photon-addition-then-subtraction operation is preferred over the photon-subtraction-then-addition for developing nonclassicality. [ABSTRACT FROM AUTHOR]

Combining immersive virtual environment (IVE) with a controlled environment is a potential solution for analyzing human thermal experience during building design. Existing studies in this field have not adequately analyzed scenarios involving stabilized comfortable and uncomfortable temperature conditions using both thermal state votes and physiological responses, or the influence of the seasons. By combining IVE with a climate chamber, called mixed IVE (MIVE) in this study, experiments were conducted to test the hypothesis that participants' virtual experience did not significantly alter their thermal experience compared to their in-situ experience. Response variables were the control temperature distribution, the thermal state vote (at temperature steps 18.3 °C, 23.8 °C, and 29.4 °C), and physiological responses (heart rate and skin temperature). The results show that the first two response variables were not significantly different between the MIVE and in-situ settings (except for one case). Due to the heat development of the head mounted display device, the mean forehead skin temperature in the MIVE experiments was significantly higher than that in the in-situ experiments in most cases. However, such difference in skin temperature did not seem to affect general thermal state votes. In addition, significant skin temperature differences at some locations were also observed between the MIVE and in-situ settings.

In practice, during the operation of steam turbines, accidental damage to the blades of the rotors and stators of powerful steam turbines occurs. The main causes of emergency stops of steam turbines were vibration fatigue of the blades material, erosive damage to the blades body, and resonance problems during the power equipment operation. Based on this study, the assessment of changes in the thermal and stress-strain state of power equipment elements, which at nuclear power plants significantly affect the continued operation of the turbine after its damage, are quite relevant. Changes in the thermal and stress-strain state, which may occur after damage to the rotor of high-pressure cylinder (HPC rotor) of the K-1000-60/3000 turbine power unit of the LMZ in the station conditions, have been considered and analyzed and will provide an opportunity to assess the individual resource and continue the power unit operation. In the calculated assessment of changes in the thermal and stress-strain state of the HPC rotor, taking into account the data of the technical audit regarding damage, a geometric model of the rotor was created. Studies were conducted for three options of designs: the original option (five stages of the HPC rotor), the option without the blades of the last stage and the option without the fifth stage (with four first stages). For the project design, when working at the nominal parameters of the steam, the most stressed areas are the unloading holes of the 5th stage (σi=202.8 MPa), axial hole of the rotor in the area of the 5th stage (σi=195.2 MPa), as well as the 5th-degree welding fillet from the side of the end seals (σi=200.3 MPa) and unloading holes of the 4th and 3rd stages with a stress intensity of about 170–185 MPa. The high values of the stress intensity in the area of the 5th stage can be explained by the significant concentration of the mass of both the stage itself and its blades, which provoke significant centrifugal forces when working at the nominal rotation frequency. For a HPC rotor without blades of the 5th stage, there is a shift of the maximum stress intensity to the area of the unloading holes of the 4th and 3rd stages, as well as the axial hole of the shaft under the same stages. The maximum stress value is σi max=184.8 MPa. At the same time, the intensity of stresses in the area of unloading holes of the 5th degree decreased almost by half, to the level of 124 MPa.

Lithium-ion batteries currently represent the dominant energy storage technology due to their superior efficiency and widespread compatibility, especially in Electric Vehicles (EVs). Normally, a Battery Management System (BMS) is used to monitor and optimize the states of these batteries in order to maintain efficient and safe operating performance. However, estimating the state of Li-ion batteries is not a straightforward process. Accordingly, there has been extensive interest in the use of Artificial Intelligence (AI) methods for this purpose.This work is a comprehensive review of Artificial Neural Network (ANN) use in the estimation of Li-ion battery states, including state of charge, state of health, remaining useful life, thermal state and other parameters. The estimation accuracy and robustness are analyzed based on error evaluation metrics alongside study remarks. It was found that feed forward neural networks were the most utilized for estimating Li-ion battery states. Moreover, convolutional neural networks have also shown good estimation performance in number of studies and illustrate huge potential. Finally, this work presents future recommendations to expand the research scope as well as maximize the applicability of ANNs as computational tools for battery technologies.

Endless rolling urgently requires an increase in the casting speed of continuous casting. For the continuous casting process of a high-casting-speed billet, the heat flux of the mold would be much higher, requiring a stronger cooling performance and longer mold life to match the high-speed casting. Mold material, thickness, and slot structure have a great influence on the casting speed. To design a more efficient billet casting mold, a three-dimensional thermal-stress-coupled analysis model of a 150 mm × 150 mm mold was established in this research to analyze the thermal state of a mold with high casting speed; in addition, the material, thickness, and water slot structure, which pertain to the mold cooling performance, were also studied. The results show that the billet mold of Cu-Ag with a thinner thickness and right-corner water slot is better in terms of casting speed. Regarding the material, the Cu-Ag mold has a higher thermal conductivity efficiency; its hot surface temperature is 4.89 °C lower, its equivalent stress is 7 MPa lower, and its longitudinal deformation is 0.0023% lower compared with the deoxidized phosphorus copper mold. Regarding the thickness, the thinner mold has a 60.76 °C lower hot surface temperature, its equivalent stress is 340 MPa lower, and its longitudinal deformation is 0.0443% lower compared with the thicker mold. For the water slot structure, the mold with the right-angled water slot has a 2.895 °C lower hot surface temperature, its equivalent stress is 37 MPa lower, and its longitudinal deformation is 0.0039% lower compared with the mold with a rounded-corner water slot. [ABSTRACT FROM AUTHOR]

During the operation of a steam turbine, its structural elements are subjected to significant thermal and mechanical loads. The consequence of the long-term effect of such a load is the accumulation of scattered fatigue damage to the material of the structural elements of the steam turbine, which is localized over time in the form of fatigue cracks of various types. Evidence of this is several accidents and catastrophic failures of steam turbines due to significant fatigue damage to the shafting. The localization of damage in turbine rotors is facilitated by stress concentration in the gouges and fillets, as well as damage to the surface layer of the rotors during the thermomechanical treatment stage since all metal processing operations (forging, turning and milling, heat treatment) are accompanied by plastic deformation of the material. One of the reasons for the long-term accumulation of fatigue damage in the structural elements of steam turbines is thermal stresses, which can reach dangerous values during turbine startup operations. In certain parts of the rotors, these stresses are sufficient to cause scattered fatigue damage to the material (the so-called thermoplasticity), especially when starting the turbine from a cold state. In the case of crack initiation, the thermal stresses are all the more sufficient for its further intensive development even when starting the turbine from uncooled and hot states, which are less damaging than starting from the cold state. To study the intensity of crack growth in the turbine rotor due to thermal stresses arising during turbine startup, a computational model based on using a finite element model of the shaft of the K-200-130 steam turbine and fracture mechanics approaches is proposed. Studies based on the proposed computational model have demonstrated the ability to predict the process of crack growth in the rotor due to turbine startup from different thermal states and assess its danger to structural integrity. The initial size of the internal annular crack was determined, which has the potential for further intensive growth under the influence of thermal stresses. [ABSTRACT FROM AUTHOR]

In this work we discuss various selected mission concepts addressing Venus evolution through time. More specifically, we address investigations and payload instrument concepts supporting scientific goals and open questions presented in the companion articles of this volume. Also included are their related investigations (observations & modeling) and discussion of which measurements and future data products are needed to better constrain Venus' atmosphere, climate, surface, interior and habitability evolution through time. A new fleet of Venus missions has been selected, and new mission concepts will continue to be considered for future selections. Missions under development include radar-equipped ESA-led EnVision M5 orbiter mission (European Space Agency 2021), NASA-JPL's VERITAS orbiter mission (Smrekar et al. 2022a), NASA-GSFC's DAVINCI entry probe/flyby mission (Garvin et al. 2022a). The data acquired with the VERITAS, DAVINCI, and EnVision from the end of this decade will fundamentally improve our understanding of the planet's long term history, current activity and evolutionary path. We further describe future mission concepts and measurements beyond the current framework of selected missions, as well as the synergies between these mission concepts, ground-based and space-based observatories and facilities, laboratory measurements, and future algorithmic or modeling activities that pave the way for the development of a Venus program that extends into the 2040s (Wilson et al. 2022). [ABSTRACT FROM AUTHOR]

We present an overall summary on a method to deal with quantum dynamics of optomechanical systems. The method is based on the dynamical evolution processes instead of the finally evolved steady states, which are a prerequisite to the standard approach, and well captures the features in optomechanical cooling, entanglement and other scenarios.

The compositional and thermal state of Earth's mantle provides critical constraints on the origin, evolution, and dynamics of Earth. However, the chemical composition and thermal structure of the lower mantle are still poorly understood. Particularly, the nature and origin of the two large low-shear-velocity provinces (LLSVPs) in the lowermost mantle observed from seismological studies are still debated. In this study, we inverted for the 3D chemical composition and thermal state of the lower mantle based on seismic tomography and mineral elasticity data by employing a Markov chain Monte Carlo framework. The results show a silica-enriched lower mantle with a Mg/Si ratio less than ~1.16, lower than that of the pyrolitic upper mantle (Mg/Si = 1.3). The lateral temperature distributions can be described by a Gaussian distribution with a standard deviation (SD) of 120 to 140 K at 800 to 1,600 km and the SD increases to 250 K at 2,200 km depth. However, the lateral distribution in the lowermost mantle does not follow the Gaussian distribution. We found that the velocity heterogeneities in the upper lower mantle mainly result from thermal anomalies, while those in the lowermost mantle mainly result from compositional or phase variations. The LLSVPs have higher density at the base and lower density above the depth of ~2,700 km than the ambient mantle, respectively. The LLSVPs are found to have ~500 K higher temperature, higher Bridgmanite and iron content than the ambient mantle, supporting the hypothesis that the LLSVPs may originate from an ancient basal magma ocean formed in Earth's early history. [ABSTRACT FROM AUTHOR]

High heat generation in the hydrodynamic wedge is one of the main factors limiting application of pad journal bearings as bearings for rotors of aircraft gas turbine engines. The goal of the research is to study the influence of the oil supply method on the bearing thermal state and to determine the design factors reducing the bearing temperature. The study was carried out with the use of bearings with diameters of 100320 mm with different design of the oil supply: through oil dispensing grooves in the pads, through oil nozzles in the inter-pad space, using lead-in chamfers for the pads, with oil bypass channels. The tasks posed were solved by using volumetric geometric models with the tools of computational fluid dynamics in the ANSYS CFX package in which differential equations describing the model are solved by the finite element method. The patterns of temperature and pressure distribution over the surface of the lower, most loaded bearing pad were obtained for various options of oil supply and different geometry of bearing pads; values of the bearing load carrying capacity, maximum pressure in the working gap, the oil mass flow through the elements of the oil supply; dependences of the bearing static performance on the distance between the shaft and nozzles. Oil supply through oil dispensing grooves made in pads is a factor that negatively affects the bearing thermal state, which is associated with so-called locking of the working gap. It is shown that implementation of oil supply through the space between the pads is more efficient. The use of a lead-in chamfer with plain inserts simplifies oil supply to the working gap. The design solutions described make it possible to reduce the maximum oil temperature in the bearing by 36 degrees Celsius.

The operation of a cryogenic fuel system is considered by means of model calculations corresponding to several flight specifications for a civil aircraft fueled by liquefied natural gas. [ABSTRACT FROM AUTHOR]

Vacuum polarization of a scalar field on the short throat wormhole background is investigated. The scalar field is assumed to be massless, having an arbitrary coupling to the scalar curvature of spacetime. In addition, it is supposed that the field is in a thermal state with an arbitrary temperature. [ABSTRACT FROM AUTHOR]

Thermal-state continuous-variable quantum key distribution (CV-QKD) of direct reconciliation with heterodyne detection can improve the robustness of the protocols. However, CV-QKD protocols require outlier detection, optical phase shifters are used to achieve orthogonal differentiation of the modes, but the actual optical phase shifters suffer from measurement angular errors, resulting in the imperfect phase. This kind of error degrades the security of the system. In this paper, we analyze the causes of measurement angular error and its impact on the secret key rate of the thermal-state CV-QKD protocols. We propose a compensation method to compensate for the effects of the measurement angular error and give a more complete secure analysis method under collective attack. The results obtained in this paper further improve the secure analysis under the thermal-state protocol and further enhance the performance of the system using the compensation method.

The well-known N-S-trending fault in the Yangbajing area plays a crucial role in the tectonic evolution of the Tibetan Plateau. Previous researches on a few E-W geophysical profiles suggested that the eastern shear at the base of the upper crust and/or lithosphere deformation brought on by asthenosphere upwelling are the major causes of the Yadong-Gulu rift’s creation. Here we propose a 3-D electrical resistivity model derived from the magnetotelluric (MT) array data spanning the Yadong-Gulu rift (YGR), and the distribution of temperature and melt fraction is estimated by the experimental calibrated relationships bridging electrical conductivity and temperature/melt fraction. The result reveals that the Indian slab subducted steeply in the east of the Yadong-Gulu rift, while Indian slab may have delaminated with a flat subduction angle in the west. The temperature distribution shows that the upper mantle of the northern Lhasa terrane is hotter than that of the southern Lhasa terrane. This is likely the result of mantle upwelling caused by either the subduction of the Indian slab or thickened Tibetan lithosphere delamination. Moreover, the strength of the mid-lower crust is so low that it may meet the conditions of the local crust flow in the west-east direction. The local crustal flow and the pulling force from the upwelling asthenosphere jointly contributed to the formation of the Yadong-Gulu rift. These main factors exist in different stages of the evolution of the Yadong-Gulu rift.

One key issue of the foundation of statistical mechanics is the emergence of equilibrium ensembles in isolated and closed quantum systems. Recently, it was predicted that in the thermodynamic ( N → ∞ ) limit of large quantum many-body systems, canonical density matrices emerge for small subsystems from almost all pure states. This notion of canonical typicality is assumed to originate from the entanglement between subsystem and environment and the resulting intrinsic quantum complexity of the many-body state. For individual eigenstates, it has been shown that local observables show thermal properties provided the eigenstate thermalization hypothesis holds, which requires the system to be quantum-chaotic. In the present paper, we study the emergence of thermal states in the regime of a quantum analog of a mixed phase space. Specifically, we study the emergence of the canonical density matrix of an impurity upon reduction from isolated energy eigenstates of a large but finite quantum system the impurity is embedded in. Our system can be tuned by means of a single parameter from quantum integrability to quantum chaos and corresponds in between to a system with mixed quantum phase space. We show that the probability for finding a canonical density matrix when reducing the ensemble of energy eigenstates of the finite many-body system can be quantitatively controlled and tuned by the degree of quantum chaos present. For the transition from quantum integrability to quantum chaos, we find a continuous and universal (i.e., size-independent) relation between the fraction of canonical eigenstates and the degree of chaoticity as measured by the Brody parameter or the Shannon entropy. [ABSTRACT FROM AUTHOR]

In this paper, thermal entanglement in four and five-qubit spin-star networks evolved by an XXX Hamiltonian model is studied. We examine the effect of temperature, magnetic field and coupling constant on the concurrence. We will show that the entanglement is decreased by increasing the temperature and the number of qubits. Also, we investigate quantum teleportation via a couple of spin-star networks in a thermal state. The average of fidelity as a function of temperature, magnetic field, and coupling constant is analyzed, too. It will be observed that as the temperature increases, the fidelity first decreases and then tends to a constant value. Moreover, with the increase of the external magnetic field, the average fidelity first increases and then gradually decreases, and in a certain amount of magnetic field, the average fidelity becomes zero. In addition, as the number of qubits increases, fidelity decreases with temperature. The results indicate that mean fidelity increases with increasing coupling constant.

The article describes how different friction coefficients under certain cutting conditions and parameters affect the formation of the stress-strain and thermal states of the product when titanium alloy machining. A new research methodology is used for the study. Firstly, in the initial data for simulation, each time a different declared coefficient of friction is proposed, and every such task of the cutting process modelling is solved for various cutting parameters. The second stage analyzes how these coefficients influence the stress-strain and thermodynamic state of the workpiece and tool during cutting, as well as the tool wear dynamics. In the third stage of the study, ways for ensuring these analytically-grounded tribological cutting conditions are proposed. The analysis of different wear criteria in the simulation models of titanium alloys cutting is carried out. Experimental studies confirm simulation results.

[Display omitted] • Develop a model to assess human thermal state based on a multilevel fuzzy integrated assessment. • Explore human thermal state in the local thermal radiation environments. • Well accuracy of human thermal state has validated via the PHS model and PSI Index. • Auditory canal temperature, heart rate, and sweat rate were weighted more heavily. Local thermal radiation in heat treating, glass melting workshops substantially affect the human thermal comfort and thermal responses, causing even the thermal health risks. The accessibility of an effective assessment of human thermal state is crucial for the thermal safety protection. A scoring for thermal state was developed based on the multilevel fuzzy integrated assessment method at three aspects: thermal environment (Air temperature and mean radiant temperature), physiological responses (Heart rate, sweat rate, auditory canal temperature, mean arterial pressure, and skin temperature), and psychological perceptions (Rating of perceived exertion and thermal perception). Scoring of thermal state (STS) was determined to be dependent on the objective weights of each index and the set of nonlinear weights. Twelve experimental cases, including air temperatures of 33 and 36 °C, mean radiant temperatures of 33.6 to 38.3 °C, and metabolic levels of 1.1, 2.9 and 4.3 met, simulated the situations of different work intensities with exposure to local thermal radiation, which were used for the validation of the STS. Results showed that the remarkable contributions of air temperature, radiant temperature, auditory canal temperature, heart rate, sweat rate, and perceived fatigue were the highest in the STS. The STS, validated with the PHS model and the PSI index, allows a well-assessed human thermal state because of its encompassing multifaceted characteristics. This study contributes to the evaluation of hot discomfort in local thermal radiation environments, revisiting the thermal comfort research method. [ABSTRACT FROM AUTHOR]

The contents of the main elements (including Ni) are presented for 1100 garnet and 831 clinopyroxene grains extracted from kimberlite of a diatrem part of the highly-diamondiferous V. Grib highly diamondiferous pipe in the Arkhangelsk diamondiferous province. The interpretation of the chemical composition of minerals and the calculated PT-parameters indicate the main characteristics of the highly diamondiferous lithospheric mantle in the region: (1) its thermal regime corresponding to 35–37 mW/m2 in the central part (120–150 km) and 37–40 mW/m2 in the upper (80–120 km) and lower (deeper than 150 km) areas; (2) the depth of the lower boundary in the range of 210–230 km; (3) the thickness of the "diamond window" of 80–110 km; and (4) the preserved potentially diamondiferous depleted rocks (harzburgites–dunites) in its central and lower parts during kimberlite magmatism. [ABSTRACT FROM AUTHOR]

The effect of shape of shock current pulses on the thermal state of a semiconductor device has been experimentally analyzed. The technological process of changing the parameters of a device under the action of disturbing factors has been described. Based on the heat-balance equation, the analytical expression to estimate the temperature of a semiconductor chip has been obtained. The experimental dependences that characterize a change in the parameters of the device under the influence of shock current pulses with various shapes has been presented. The characteristics of the device when using sinusoidal current pulses and dc pulses have been compared. [ABSTRACT FROM AUTHOR]