Temperature Domain Research Articles

An Unpaired Thermal Infrared Image Translation Method Using GMA-CycleGAN

Automatically translating chromaticity-free thermal infrared (TIR) images into realistic color visible (CV) images is of great significance for autonomous vehicles, emergency rescue, robot navigation, nighttime video surveillance, and many other fields. Most recent designs use end-to-end neural networks to translate TIR directly to CV; however, compared to these networks, TIR has low contrast and an unclear texture for CV translation. Thus, directly translating the TIR temperature value of only one channel to the RGB color value of three channels without adding additional constraints or semantic information does not handle the one-to-three mapping problem between different domains in a good way, causing the translated CV images not only to have blurred edges but also color confusion. As for the methodology of the work, considering that in the translation from TIR to CV the most important process is to map information from the temperature domain into the color domain, an improved CycleGAN (GMA-CycleGAN) is proposed in this work in order to translate TIR images to grayscale visible (GV) images. Although the two domains have different properties, the numerical mapping is one-to-one, which reduces the color confusion caused by one-to-three mapping when translating TIR to CV. Then, a GV-CV translation network is applied to obtain CV images. Since the process of decomposing GV images into CV images is carried out in the same domain, edge blurring can be avoided. To enhance the boundary gradient between the object (pedestrian and vehicle) and the background, a mask attention module based on the TIR temperature mask and the CV semantic mask is designed without increasing the network parameters, and it is added to the feature encoding and decoding convolution layers of the CycleGAN generator. Moreover, a perceptual loss term is applied to the original CycleGAN loss function to bring the translated images closer to the real images regarding the space feature. In order to verify the effectiveness of the proposed method, the FLIR dataset is used for experiments, and the obtained results show that, compared to the state-of-the-art model, the subjective quality of the translated CV images obtained by the proposed method is better, as the objective evaluation metric FID (Fréchet inception distance) is reduced by 2.42 and the PSNR (peak signal-to-noise ratio) is improved by 1.43.

Prediction of the tribological properties of a polymer surface in a wide temperature range using machine learning algorithm based on friction noise

A signal processing method based on friction noise is introduced to predict the tribological properties of polymers in a wide temperature domain. Three different machine learning algorithms, XGBoost, LightGBM and CatBoost are used to establish a mapping relationship between the time–frequency domain features of friction noise and the friction coefficient. The friction coefficients of pairs of four polymers and seven metals are predicted at five temperatures and three load/speed conditions of point contacts in a wide temperature domain from − 120–25 ℃. Performance analysis reveals that the machine learning approach satisfactorily predicts the friction coefficients of different polymer–metal pairs in a wide temperature range from tribological test data. This method can be used for in-situ monitoring on tribological properties.

A multifunctional molecular ferroelectric with a high Curie temperature and electrical–thermal double-switch coexistence: (C8H14NO)[FeCl4

We report a new multifunctional organic-inorganic hybrid ferroelectric (C8H14NO)[FeCl4]. It has a high Curie temperature and clear ferroelectric domains.

A critical analysis of the AHRI polynomials for scroll compressor characterization

• Scroll compressor energy and mass flow surfaces with evaporating and condensing conditions. • ARHI polynomials overfit scroll compressor behavior. • Two-degree polynomials are more indicated to scroll compressors. • Less experimental points are required to characterize scroll compressor. • Pressure as polynomial variable is more suitable than temperature. This paper presents the analysis of the energy consumption and mass flow rate of scroll-type compressors. The study has included the data of several AHRI reports (especially AHRI 11 and AHRI 21) and data from other sources. A total of 7 different scroll compressors of different sizes have been considered in the study, some of them tested with various refrigerants (R134a, R32, R410A, R404a…). For all the studied compressors and refrigerants, the compressor energy consumption and mass flow rate values have been analyzed. The main objective is to better understand the dependence of these variables on the operating conditions and the refrigerant used. The analyzed data include tests following different superheat control, i.e., constant superheat or constant return temperature, so the effect of the inlet temperature on these variables is also discussed. As the main novelty of this study, the analysis of the response surfaces has allowed the authors to evaluate the most suitable correlation to use, including an analysis of the necessary experimental tests and where to place them to increase the model's accuracy. It was found that using the condensing and evaporating pressure terms is more universal than the classical temperature domain. In scroll compressors, AHRI polynomials overfits the compressor performance introducing significant deviations in the interpolation and extrapolation capabilities if the experimental data are not properly selected. Finally, it was found that lower degree polynomials are more suitable for this kind of compressor and has also the advantage of requiring fewer experimental point measurements to characterize the compressor with the corresponding cost-savings.

Effect of annealing treatment on the magnetic properties with wide temperature range of Co-doped FeSi soft magnetic composites

Fe-Si-Co soft magnetic composites (SMCs) coated with silicone resin were successfully prepared in this work. The influences of annealing treatment on the temperature/frequency-dependent behaviors of magnetic properties for SMCs were studied by microstructureanalysis and loss separation. Results show that the core loss of Fe-6.5Si-1.0Co SMCs gradually decreases with annealing temperatures rising from 500 °C to 700 °C when measured at 50 kHz, while the core loss of Fe-6.5Si-3.0Co SMCs first decreases then increases. Meanwhile, the effective permeability Fe-6.5Si-1.0Co and Fe-6.5Si-3.0Co SMCs are significantly improved. Simultaneous optimization for core loss and effective permeability benefits from the residual stress relief and defect elimination induced by annealing. Fe-6.5Si-1.0Co SMCs annealed at 700 °C shows excellent comprehensiveperformances with core loss of 766.7 mW/cm3 and effective permeability of 112.3 measured at 0.1 T / 50 kHz. While annealing at excessive temperature causes the phase transition and change in resistance of silicone-resin coatings, leading to the rapid deterioration of the magnetic performances. As for the temperature characteristics, the Fe-Si-1.0Co SMCs also exhibits good stability for effective permeability and negative correlation for core loss with the measuring temperature ranging from −25 °C to 125 °C. This work may provide some theoretical support for the wide temperature domain application of the Co-doped FeSi SMCs.

Rheology of Conductive High Reactivity Carbonaceous Material (HRCM)-Based Ink Suspensions: Dependence on Concentration and Temperature.

The present case study reports a shear rheological characterization in the temperature domain of inks and pastes loaded with conductive High Reactivity Carbonaceous Material (HRCM) consisting mainly of few-layers graphene sheets. The combined effect of filler concentration and applied shear rate is investigated in terms of the shear viscosity response as a function of testing temperature. The non-Newtonian features of shear flow ramps at constant temperature are reported to depend on both the HRCM load and the testing temperature. Moreover, temperature ramps at a constant shear rate reveal a different viscosity-temperature dependence from what is observed in shear flow ramps while maintaining the same filler concentration. An apparent departure from the well-known Vogel-Fulcher-Tamman relationship as a function of the applied shear rate is also reported.

Partial melting and reaction along deformation features in plagioclase

AbstractGeological processes involving deformation and/or reactions are highly influenced by the rock grain size, especially if diffusion‐controlled processes take place such as metamorphic reactions and diffusion creep. Although many processes, inducing grain‐size reduction, are documented and understood at relatively high stresses and low temperatures (e.g., cataclasis) as well as at lower stress and higher temperature conditions (e.g., bulging and subgrain rotation), deformation twinning, a plastic deformation mechanism active in various minerals at lower temperatures, has been neglected as nucleation site for melting and reaction and thus as a cause for grain‐size reduction so far. We conducted experiments on natural plagioclase‐bearing aggregates at 2.5 to 3 GPa confining pressure and temperatures of 700°C to 950°C using two different deformation apparatus, a deformation multianvil apparatus (DDIA) and a Griggs press, as well as a piston‐cylinder apparatus. Regardless of the apparatus type, we observe the breakdown of plagioclase into an eclogite‐facies paragenesis, which is associated with partial melting in the high temperature domain of the eclogite facies. Partial melting mostly takes place along the grain and interphase boundaries. However, several melt patches or plagioclase decomposition products coincide with the occurrence of deformation twins and grain‐scale microcracking in plagioclase indicating intracrystalline melting and reaction in addition to melting and reaction along grain and interphase boundaries. In the present study, we demonstrate how the interplay between brittle microcracking and plastic deformation twinning can cause intracrystalline melting and/or reaction, which has the potential to lower the effective grain size of plagioclase‐rich rocks and thus impacts their reactivity and deformation behaviour.

THERMAL VARIATION OF THE DIFFERENT LAYERS FORTARFAYA DEPOSIT (MOROCCO) IN HYDRODESULPHURIZATION AS WELL AS HYDROGENATION OF CALCIUM Α, ꞵAND MAGNESIUM AT 550°C AND 750°C.

Hydrodesulphurization (HDS), deuteriodesulphurisation, calcium hydrogenation and deuterium treatment are reactions that occur simultaneously when oil shales are treated with hydrogen. In this work, quantitative monitoring of the target elements (sulphur, calcium and magnesium) was carried out using the dispersive X-ray diffraction technique (a technique coupled with a scanning electron microscope). The treatment of oil shale with hydrogen with the objective, either to improve the products preventing oil shale (gas, oil and solid fuel) or in the particular sense to get rid of some undesirable elements having harmful effects on the course of the exploitations of materials we quote the phenomenon of corrosion. An example of this is hydrodesulphurization, which is a reaction that is used to remove sulphur. This hydrogenation reaction was followed in a first work for the different oil shale layers of Tarfaya (M. Hafid and A.Attaoui: 2022) at a temperature of 550°C. However we were able to raise the temperature to 750°C for this study, in the same sense of the continuity of the action by hydrogen on elements such as calcium and magnesium in the temperature domains this study has been continued.

Measuring and Regression Modeling of Gas–Particle Partitioning of Atmospheric Oxidized Mercury at a Coastal Site in Shanghai

Gas–particle partitioning between reactive gaseous mercury (RGM) and particle bound mercury (PBM) controls the fates of atmospheric oxidized mercury (namely reactive mercury, RM). We conducted a long-term observations of gaseous elemental mercury (GEM), RGM, PBM, and auxiliary parameters in Chongming Island, Shanghai, China, to understand the characteristics of speciated mercury and their gas–particle partitioning behaviors. The entire average abundances of GEM, RGM and PBM were 2.12 ± 0.94 ng/m3, 14.75 ± 9.94 pg/m3 and 21.81 ± 30.46 pg/m3, respectively. An observation data dependent empirical gas–particle partitioning relationship of partitioning coefficient and temperature log(1/KP) = −2692.20/T + 10.57 was obtained, and it varied in different season being by the temperature. To further evaluate the influences of temperature, particulate matter (PM), relative humidity on RGM and PBM partitioning process, the particulate fraction (φ = PBM/(PBM + RGM)) was used in this study. High φ values (φ > 0.8) mainly occurred at low temperature domain (<281 K), and high PM concentration enhanced this influence. In addition, high relative humidity shifts RGM from atmosphere partitioning to PBM in response to the diurnal valley φ values at 13:00–16:00 in the summer. Photochemical reactions were proposed to play important roles on partitioning processes between RGM and PBM. This study will benefit for the understanding of oxidized mercury fate and influencing factors in the complex atmospheric pollutants.

Thermal and electrical transport in partly-reduced graphene oxide films: The effect of low temperature and structure domain size

Understanding the effect of grain size on the overall electrical and thermal transport properties of PRGO films on a large scale is not only fundamental but also technologically important in order to tune their properties for wide applications. In this work, by adjusting the annealing temperature, we control the density of the oxygen containing functional groups and thus the structural domain size of PRGO film. The annealing effect on the temperature dependency of thermal and electrical transport is studied. In addition, the linear relationship between thermal diffusivity and electrical conductivity is confirmed from 320 K to 10 K. The temperature dependent thermal diffusivity of the amorphous region in PRGO is reported. In the last, based on the residual thermal reffusivity at 0 K limit, the structure defects induced phonon mean free path against the annealing temperature is obtained, and compared with the cluster size calculated from XRD, TEM and Raman. A linear relationship among the structure domain size, thermal diffusivity, and electrical conductivity is further revealed, which demonstrates the strong effect of structure domain size on the thermal and electrical transport of PRGO.

Thermal equation of states for body-centered cubic tungsten using extended analytic embedded-atom model

Here the thermal equation of states (EOS) for body-centered cubic (bcc) tungsten (W) is evaluated using embedded atom method (EAM). To reproduce the materials properties under high pressure and high temperature reasonably well, we extend EAM by improving the analytic expressions of the functions of electron density and embedding energy based on the quantum-mechanical results of the electron density distribution and the energy variation with respect to the electron density. Then we determine the parameters of the extended analytic model for bcc W. We evaluate volume dependence of structure energy, elastic properties as function of volume, monovacancy and divacancy properties, lattice vibration at various volumes, and variation of the Gibbs free energy with respect to temperature, pressure and volume within the framework of the quasiharmonic approximation. By minimizing the Gibbs free energy, we determine the thermal EOS, variation of volume or lattice parameter with respect to pressure and temperature. The linear thermal expansion coefficient as function of temperature under different pressures is also evaluated. All calculation results fit well to the experimental and other reliable theoretical calculation results, showing the reliability of the extended analytic EAM in the extended domains of electron density, atomic volume, temperature and pressure.

Migration of carbon atoms in irradiated and non-irradiated alpha-iron studied by magnetic after-effect

Magnetic After-Effect (MAE) and magnetic AC susceptibility studies have been performed on high-purity non-irradiated and Fe-ion irradiated, α-Fe foil samples in the high-temperature range, which became experimentally accessible recently. The pronounced difference in the temperature profile of MAE between non-irradiated and irradiated samples has been identified and ascribed to the trapping of carbon in the irradiated sample into structures that are reluctant to decompose by standard temperature cycling. The accurate background of MAE relaxations at 430 and 610 K in non-irradiated α-Fe samples has been scrutinized by the annealing-type studies in temperature and time domains to conclude that it relies on the formation, decomposition, and mutual transformations of carbide nanoprecipitates nucleated in dislocations, grain boundaries, and in the bcc matrix. Long-term trapping of migrating carbon into carbides and in the 100 nm thick surface layer has also been shown to take place.

Evaluation of daily average temperature trends in Kerala, India, using MERRA-2 reanalysis data: a climate change perspective.

Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) data for a period of 40years (1980-2019) was used to detect the trend characteristics of daily average temperature in the state of Kerala, India. Data extracted from a total of fifty locations in the state were statistically processed using Mann-Kendall (MK) and Spearman's Rho (SR) tests to detect the trend, Pettitt test to identify the single change point, and Theil-Sen's method for the calculation of the rate of change. The MERRA-2 product is validated for the study region according to statistical indicators. The daily average temperature in the state during the period of study varies between 16.56 and 32.64°C. The spatial pattern of daily average maximum temperature shows higher temperature domains in the central and southern parts of the state. Trend characteristics of daily average temperature assessed through MK and SR tests show a significant increasing trend in all stations, with maximum values in stations located in the northern part of the state. Change point detected through the Pettitt test divided the sampling stations into three groups based on the change in daily average temperature characteristics in the years 2002 (north zone), 2009 (south zone), and 2012 (central zone), indicating nonunique spatial variability in temperature characteristics in the state. The rate of change in the daily average temperature assessed indicates an increase at the rate of an average of 0.013°C.year-1. During the whole study period, the daily average temperature showed an overall increase of 0.54°C, and for the 100-year futuristic prediction, the daily average temperature in the state shows an average increase of 1.35°C. Among the stations, a higher rate of increase in daily average temperature is shown by stations located in the eastern part of the Pathanamthitta, Idukki, and Kollam districts. Though the rise in daily average temperature is not much higher, its spatial characteristics require more attention because, in recent times, the study area has faced repeated, severe, and long drought conditions along with sunburn incidents. As an agrarian state, a change in the temperature domain will adversely affect the overall agricultural production and will evoke not only a food crisis but also economic as well as water resources issues. The result obtained can be used as holistic basic information for understanding the impending effect of climate change in the state to frame better mitigation as well as management strategies.

Quantifying the effects of dissipation and temperature on dynamics of a superconducting qubit-cavity system

The superconducting circuits involving Josephson junction offer macroscopic quantum two-level system (qubit) which are coupled to cavity resonators and are operated via microwave signals. In this work, we study the dynamics of superconducting qubits coupled to a cavity with including dissipation in a subKelvin temperature domain. In the first step, a classical finite element method is used to simulate the cavities and basic circuit elements to model Josephson junctions. Then, the quantization of the circuit is done to obtain the full Hamiltonian of the system using energy participation ratios of the junctions. Once the parameters of Hamiltonian are obtained, the dynamics is studied via the Lindblad equation for an open quantum system using a realistic set of dissipative parameters and include temperature effects. Finally, we get frequency spectra and/or dynamics of the system with time which have quantum imprints. Such devices work at tens of milliKelvins and we search for a set of parameters which could enable to observe quantum behaviour at temperatures as high as 1 K.

Quantum expression for the electrical conductivity of massless quark matter and of the hadron resonance gas in the presence of a magnetic field

We have studied the classical and quantum expressions of electrical conductivity and their numerical estimation in the presence of a magnetic field for hadron resonance gas (HRG) and massless quark matter. Classical results of transport coefficients of HRG matter in the presence of a magnetic field were studied previously by Dash et al. [Phys. Rev. D 102, 016016 (2020)] using the standard relaxation time approximation in the Boltzmann equation. In the same reference, the transition from isotropic transport coefficients to anisotropic coefficients in the presence of a magnetic field was also estimated for massless and HRG matter. This led to an upper limit or Stefan-Boltzmann (SB) type limit to the nonperturbative domain transition of transport coefficients. In a similar context, the present work has concentrated on the classical to quantum transition of HRG transport from the domain of high temperature and low magnetic field to that of low temperature and high magnetic field. We have also compared the quantum modification of HRG results with that of massless quark matter, where we observed an opposite trend. A similar kind of quantum effect is also noticed between mesons and baryons due to their different particle distribution functions. Despite the fact that HRG contains both mesons and baryons, Landau quantization of its net magnetothermodynamic phase space reveals meson- or boson-dominated quantum modification. That is why the quantum modification of HRG results reveals the opposite trend from that of massless quark matter, which faces fermionic quantum modification.

Conventional Half-Heusler alloys advance state-of-the-art thermoelectric properties

Half-Heusler phases have garnered much attention as thermally stable and non-toxic thermoelectric materials for power conversion in the mid-to-high temperature domain. The most studied half-Heusler alloys to date utilize the refractory metals Hf, Zr, and Ti as principal components. These alloys can quite often achieve a moderate dimensionless figure of merit, ZT, near 1. Recent studies have advanced the thermoelectric performance of half-Heusler alloys by employing nanostructures and novel compositions to achieve larger ZT, reaching as high as 1.5. Herein, we report that traditional alloying techniques applied to the conventional HfZr-based half-Heusler alloys can also lead to exceptional ZT. Specifically, we present the well-studied p-type Hf0.3Zr0·7CoSn0·3Sb0.7 alloys, previously reported to have a ZT near 0.8, resonantly doped with less than 1 atomic percent of metallic Al on the Sn/Sb site, touting a remarkable ZT near 1.5 at 980 K. This is achieved through a significant increase in power factor, by ∼65%, and a notable but appreciably smaller decrease in thermal conductivity, by ∼13%, at high temperatures. These favorable thermoelectric properties are discussed in terms of a local anomaly in the density of states near the Fermi energy designed to enhance the Seebeck coefficient, as revealed by first-principles calculations, as well as the emergence of a highly heterogeneous grain structure that can scatter phonons across different length scales, effectively suppressing the lattice thermal conductivity. Consequently, the effective mass is significantly enhanced from ∼7 to 10me within a single parabolic band model, consistent with the result from first-principles calculations. The discovery of high ZT in a commonly studied half-Heusler alloy obtained through a conventional and non-complex approach opens a new path for further discoveries in similar types of alloys. Furthermore, it is reasonable to believe that the present study will reinvigorate effort in the exploration of high thermoelectric performance in conventional alloy systems.

Investigation of a defect in the β-Ga2O3 substrate material from capacitance transients

The defect ∼0.8 eV below the conduction band edge of β-Ga2O3 wide bandgap semiconductor is investigated using the matched Arrhenius-equation projection technique that offers substantial improvement over the conventional deep level transient spectroscopy technique. An experimental technique is developed to extract activation energy Ea and attempt-to-escape frequency ν0 of defects bypassing both the rate-window treatment and the Arrhenius plot. Only raw capacitance transients in the time domain are needed with this technique. The capacitance transients are projected between the temperature and time domains as well as to Ea and ν0 domains. Extraction of Ea and ν0 is accomplished by matching the projected and experimental capacitance transients to each other.

Strengthening behaviour and failure analysis of hot-rolled Nb+V microalloyed steel processed at various coiling temperatures

The present work investigated the role of thermomechanical processing and coiling temperature on various strengthening mechanisms in a low carbon Nb + V microalloyed steel and its mechanical properties. The sample was subjected to 50 % thickness reduction by hot-rolling at 1100 °C and then air cooling directly to a coiling temperature maintained in the range of 650–500 °C. At the coiling temperature, an isothermal holding period was maintained for 1 h followed by water quenching to room temperature to preserve the sample microstructure. The microstructural characterization reveals a duplex/triplex phase mixture depending on the coiling temperature affecting its mechanical properties. For the coiling temperature range of 650–550 °C, the pro-eutectoid ferrite + pearlite phase mixture is evolved resulting an adequate ductility of ∼28 % with a tensile strength of ∼650 MPa. The strength-ductility combination was not altered much at the coiling temperature of 500 °C (i.e., near the bainitic transformation temperature domain), though a trace quantity (∼5 %) of Widmanstatten ferrite (WF) is nucleated along with the pro-eutectoid ferrite + pearlite microstructure. The isothermal holding further led to the nucleation and growth of niobium and vanadium-rich fine carbides with fcc crystal structure, which are mostly incoherent with the ferrite matrix phase. Though these precipitates were nucleated within the matrix grains due to induction of strain, the volume fraction was too low (∼1 %) to offer a substantial amount of precipitation strengthening (26–35 MPa) as compared to the grain refinement strengthening (126–156 MPa) and dislocation strengthening (115–150 MPa). The SEM analysis indicated that the segregated Mn and S atoms formed MnS inclusion at the phase interface of ferrite and pearlite, which operates as potential nucleation sites for crack initiation during tensile deformation.

Characterization of compatibility of Polypropylene/Poly(butylene succinate) blends: Impact of weight ratios on interfacial polarization

The main focus of the present work is the investigation of the aliphatic polyesters blend’s compatibility from the viewpoint of dielectric and structural properties. Polypropylene/poly(butylene succinate) (PP/PBS) polymer blends with different weight ratios were prepared using a twin-screw extruder and then a molded injection. The impact of blending PP and PBS on the molecular relaxation process and interfacial polarization of PBS was studied via broadband dielectric spectroscopy (BDS) over a large temperature domain varying between 20 °C and 100 °C and a frequency range from 0.1 Hz to 1 MHz. Three significant dielectric processes α-primary relaxation attributed to glass transition, and two interfacial polarizations due to the semi-crystalline character of PBS and the blended PP polymer are revealed and examined using the Havriliak-Negami (HN) fit. The most important point of the HN fit analysis is the study of the interaction of the dipoles trapped at the interfaces PP/PBS that allowed us to understand the state of the PP and PBS blend in terms of adhesion and compatibility. Atomic force microscope (AFM) and its electric mode electrostatic force microscopy (EFM) and differential scanning calorimetry (DSC) were performed as complementary techniques. AFM/EFM analysis and DSC thermograms confirm the poor compatibility and immiscibility between the two phases of the polymer blends (PP/ PBS).

Complementary transient thermal models and metaheuristics to simultaneously identify linearly temperature-dependent thermal properties of austenitic stainless steels

This paper presents an experimental approach for simultaneously identifying the temperature-dependent thermal conductivity (k) and specific heat (c p ) of 304 austenitic stainless steel (ASS) using complementary transient experiments and metaheuristics. Inverse thermal analysis was based on two heat conducting solids with different geometries. In estimation problems in general, one seeks to obtain as much sensitive data as possible using as few sensors as possible. Single thermocouple data were collected for each thermal model. An objective function fitting these complementary measurements to the corresponding numerical temperatures was minimized using the Lichtenberg algorithm. This metaheuristic algorithm takes advantage of more sensitive information provided by using complementary data, enabling for an accurate inverse solution, even when dealing with wide search ranges. The proposed technique provides a cost-effective and robust property estimation from tests conducted at room temperature. Single-step estimation occurred throughout the whole temperature domain to determine the parameters for linear functions representing the temperature dependence of k and c p . The obtained lines agreed well with curves from the literature. The 95% confidence bounds for the parameters of interest indicated deviations below ± 8.5%. Error analysis considering numerical and experimental processes showed an uncertainty close to ± 3%, applied to all estimated parameters.