High Temperature Radiation Research Articles

Navigating climate shifts for an endemic lizard from a semi-arid environment

Ecological niche models (ENMs) are crucial for understanding species distribution and identifying areas maintaining climatic stability over time (i.e., thermal refugia). Human-induced global climate change underscores the importance of such refugia, which directly impacts species distribution, especially for ectothermic species relying on the environmental temperature to keep their metabolism active. Tropidurus cocorobensis is an endemic, heliothermic, and generalist lizard from Caatinga, a heterogeneous semi-arid domain characterized by low and irregular precipitation patterns and high temperature and solar radiation. Despite its endemism, there is no information concerning temporarily stable (refugial) and unstable (recently colonized) regions for its occurrence, nor future predictions of local thermal suitability in different climate change scenarios. Using ENMs, we assessed Caatinga's past, present, and future thermal suitability for T. cocorobensis, identifying potential changes in its thermal refugia over time. Our results indicated Depressão Sertaneja Meridional (DSM) and Campo Maior Complex (CMC) as climatically stable Caatinga Ecoregions, serving as climate refugia for T. cocorobensis. While DSM covers much of the species' current distribution, CMC lacks occurrence data. Contrastingly, the Chapada Diamantina Complex, a known habitat for the species, was not recovered as a climate refugia nor was suitable for future scenarios, therefore representing a climatically unstable area. Future projections indicate a potential expansion of T. cocorobensis' climate refugia, possibly linked to the species' generalist habits. However, the optimistic outlook for this species may not mirror the overall well-being of the Caatinga domain since generalist species often fill niches left by specialists unable to adapt to stressful environments. Future studies should prioritize comparing the climatic refugia of specialist and generalist species envisioning a comprehensive understanding of the ecological dynamics within the Caatinga ecosystem. This approach will be crucial for formulating effective conservation strategies amid the ongoing challenges of climate change in this domain.

High-temperature mechanical properties and radiation resistance properties of reduced-activation high-entropy alloys FeMnCrTi0.1

High-temperature mechanical properties and radiation resistance properties of reduced-activation high-entropy alloys FeMnCrTi0.1

Dependence of the silicon carbide radiation resistance on the irradiation temperature

The effect of high-temperature electron and proton irradiation on the characteristics of devices based on SiC has been studied. For the study, industrial 4H-SiC integrated Schottky diodes with an n-type base with a blocking voltage of 600, 1200 and 1700 V manufactured by CREE were used. Irradiation was carried out by electrons with an energy of 0.9 MeV and protons with an energy of 15 MeV. It was found that the radiation resistance of SiC Schottky diodes under high-temperature irradiation significantly exceeds the resistance of diodes under irradiation at room temperature. It is shown that this effect arises due to the annealing of compensating radiation defects under high-temperature irradiation. It is shown that this effect arises due to the annealing of compensating radiation defects under high-temperature irradiation. The parameters of radiation defects were determined by the method of non-stationary capacitance spectroscopy. Under high-temperature (“hot”) irradiation, the spectrum of radiation-induced defects introduced into SiC differed significantly from the spectrum of defects introduced at room temperature. The radiation resistance of silicon and silicon carbide is compared. The relatively small difference in the rate of removal of carriers in SiC and Si upon irradiation at room temperature is due to the fact that in SiC, in contrast to Si, there is practically no annealing of primary radiation defects during irradiation.

Peak Response Wavelength Tunable 4H-SiC UV Detector Covering Near-Ultraviolet Region With High-Temperature Stability and Radiation Hardness

Peak Response Wavelength Tunable 4H-SiC UV Detector Covering Near-Ultraviolet Region With High-Temperature Stability and Radiation Hardness

Thermodynamic Analysis of the Concentration Process of Solar Radiation

Extremely rarefied but high-temperature solar radiation energy is nowadays commonly concentrated to produce a high-temperature heat source. The article is a contribution to theoretical considerations on the process of concentration of solar radiation. The process of concentration of extraterrestrial solar radiation was subjected to thermodynamic analysis and the energetic, entropic and exergetic points of view were taken into account. An imaginary model of concentration was defined, which allowed the development of thermodynamic analyses of the concentration process. In the model, concentrated solar radiation irradiates the absorbing surface, the temperature of which is controlled by the intensity of cooling. The newly revealed values of temperature (7134 K) of the Sun's surface and its energetic and exergetic emissivity (0.431 and 0426, respectively) were used in the analyses. With the use of model equations, the relationship between the ratio of radiation concentration, temperature and emissivity of the absorption surface, cooling intensity, absorbed heat, ambient temperature, and energy and exergetic efficiency of the concentration process was determined. Entropy analysis confirmed that the concentration limit temperature is equal to the temperature of the Sun's surface. Examples of energy and exergetic balances of the concentration process, illustrated by band diagrams, showed the percentage share of energy and exergy fluxes. In contrast to the energy balance showing no energy loss, the exergy balance showed a significantly large loss of exergy due to the irreversibility of the process. The components of this irreversibility have been identified, which are the absorption of solar radiation and the much lower irreversibility of the emission of the heated surface.

Novel high temperature tritium blanket designs for confined spaces in spherical tokamak fusion reactors

Tritium self-sufficiency is one of the fundamental challenges for commercially viable deuterium–tritium nuclear fusion power stations. The combination of key high temperature radiation shielding materials that possess dense, high neutron absorption cross-section, and moderation properties, and tritium breeding materials could involve interesting design spaces for the central column challenge in spherical tokamaks. Potential tungsten alloys can be used for two functions: radiation shielding and structural material, providing a new design space window for spherical tokamak central column breeding space. In this paper, we present two novel high temperature concepts for the inboard side of the breeder blanket in a confined space, such as a spherical tokamak. A tungsten–rhenium–hafnium-carbide lithium-based design was found to offer the best TBR given a parameter optimisation based on shielding and thermal requirements. A silicon-carbide lead-lithium breeder design was also investigated. The highest TBR was found to be 0.135 in a 3D neutronics calculation with a W-24.5Re-2HfC (structural and shielding, wt%), Li (90% Li-6 enriched breeder), and tungsten pentaboride (W2B5) (shielding) option. Although this TBR is lower than unity, it will contribute to the reactor’s global TBR.

Fabrication of Cost-Effective Carbon-Based Multiporous-Layered-Electrode Perovskite Solar Cells

To be commercialized photovoltaic panels, one of the most important issue is the stability. Normally, thin-film perovskite solar cells have been suffered from it. Contrary, carbon-based multi-porous-layered-electrodes perovskite solar cells (MPLE-PSCs) have enough stability for it. Specially, the porous carbon electrodes have five merits for the stability as below,[1] high stability against halogen in perovskite crystal (Au and Ag can be damaged by the halogen)[2] high conductivity to be the back contact electrodes (the sheet resistance can be around 5 ohm/square)[3] strong hole-extraction ability (in place of organic hole-transporting material)[4] water absorption ability as activated carbon after annealing procedure at 400 °C[5] water blocking ability after making photovoltaic device with perovskite crystalHence, such porous carbon electrodes enhance the stability of MPLE-PSCs. Moreover, the merits for the commercialization of MPLE-PSCs can be listed as,[1] high stability against high temperature and strong radiation against sun illumination1-1 Thermal stability at 100 ֩C over 4500 h in dark (by Univ. of Hyogo, Japan).1-2 Damp-heat stability at 85 ֩C-85%RH over 3,000 h in dark (by Univ. of Hyogo and Kishu Giken Kogyo, Japan).1-3 Light stability at 55 ֩C over 10,000 h (by EPFL, Switzerland ).[2] relatively photoenergy conversion efficiency for the utilization (11.5% as module)[3] cost-effective fabrication process by fully-printing method under ambient air (without glove box and dry room)[4] Recyclable deviceIn the conference, the fabrication technology and the challenging works of high thermal stability at 140 ֩C will be presented.

Decoupling irradiation effects on deformation-induced martensitic transformations in commercial Ni-Cr-Fe alloys

This study deconvolutes the roles of irradiation-induced cavities and dislocation loops on deformation-induced martensitic transformations in Ni-Cr-Fe alloys. Until recently, martensitic transformations were not thought possible in these materials due to their high stacking fault energy. But mechanical martensitic transformations can be activated by nanoindentation, prompting a need to understand the role of defects such as those which would be generated during service in high temperature irradiation environments, on the extent of the transformations. Here, commercial Alloy 625 and Alloy 690 are irradiated with neutrons, protons, or He ions at 400 °C to create microstructures containing loops and cavities, predominantly loops, or predominantly cavities, respectively. Nanoindentation on irradiated {101} grains are dissected, and their deformation microstructures are characterized using post-mortem transmission electron microscopy (TEM). In Alloy 625, all irradiation types either partially or fully suppress the fcc → hcp → bcc transformation, whereas in Alloy 690, irradiation promotes the transformation, with neutron irradiation exhibiting the most mature fcc → hcp transformation. Irradiation defects compete to influence the martensitic transformation through a competition between increasing free energy and increasing hardening. Cavities increase free energy more than they increase hardening, thus promoting transformation, whereas loops hinder transformation because they increase hardening more than free energy. These findings have significant implications on the evolution of mechanical behavior and thus the safety factor of Ni-Cr-Fe alloy components under irradiation.

Stability of stationary solutions for inflow problem on the thermally radiative magnetohydrodynamics

In this paper, the inflow problem for the thermally radiative magnetohydrodynamics in a half line is investigated by using an L2-energy method in the case that we consider the effects of high temperature radiation (pressure p=Rρθ+a3θ4, internal energy e=Cvθ+aρθ4).

An analytical I-V model of SiC double-gate junctionless MOSFETs

Silicon carbide(SiC) double gate junctionless metal oxide semiconductor field-effect transistors(DG JL MOSFETs) have attracted significant attention due to their ideal high temperature characteristics and radiation resistance. Therefore, it is meaningful to exploit an I-V model for SiC DG JL MOSFETs. In this article, we make a linear approximation to describe the relationship between the surface mobile charge density and the surface electron concentration of the device. Based on this approximation and using the one-dimensional Poisson’s equation, we solve for the potential distribution of a SiC DG JL MOSFET in the subthreshold region. From this solution, we derived a functional relationship between the surface mobile charge density in the channel and the channel quasi-Fermi potential. Then we successfully developed a unified I-V model for the SiC DG JL MOSFETs. Based on the drain to source current calculation formula, the calculation expressions for the device’s transconductance and output conductance are derived. By comparing our model with the results from the two-dimensional numerical simulation software Silvaco Atlas, our model’s calculations closely match the two-dimensional numerical simulation results from the subthreshold region to the accumulation region. This model has reference significance for SiC DG JL MOSFETs in the high temperature electronic circuit application field.

Internal stress analysis of irradiated graphite cores in a gas-cooled microreactor

The structural integrity of core graphite under high-temperature irradiation conditions is crucial for the safe operation of the reactor. This paper presents a simulation of the hexagonal core graphite structure, developed using the UMAT program. Design factors, including irradiation, high temperature, dimensional strain, and creep strain, are analyzed separately through the control variable method. The results indicate a positive correlation between the magnitude of the irradiation field gradient and the resulting stress effects. Stress concentration within the temperature field is observed to occur near the inner side of the hexagonal prism. Among the four types of graphite examined, PCIB demonstrates the least stress and deformation, making it more suitable for specific applications. The selection of graphite should consider the particular service period requirements. Choosing a graphite material that exhibits minimal shrinkage and a high turnaround dose is advisable. The primary creep parameter is negligible when compared to the secondary creep parameter; selecting graphite with a larger secondary creep parameter enhances reactor safety. The findings of this study provide a solid foundation for the design of a graphite core and offer recommendations for graphite candidates in the development of microreactors in China.

Co-evolution of M23C6 precipitates and cavities in a boron-free Ni-based alloy GH3617 under high-temperature He ion irradiation: Effects on cavity swelling and mechanical properties

Ni-based alloys are promising materials for advanced nuclear reactors operating at high temperatures due to their exceptional resistance to high temperatures and corrosion. Understanding the synergy of phase stability and helium effects is crucial for assessing the long-term performance and reliability of these alloys in advanced nuclear reactors. This study has investigated the co-evolution behavior of M23C6 precipitates and cavities in a boron-free solid solution strengthened Ni-based alloy GH3617 under high-temperature He ion irradiation, and its impact on alloy swelling and mechanical properties, by He ion irradiation experiments with the highest fluence of 1 × 1017 He/cm2 up to 800 °C. Transmission Electron Microscopy (TEM) and Nanoindentation are employed to investigate microstructural evolution and mechanical properties, respectively. The findings show that at room temperature and 500 °C, cavities and dislocation loops were the dominant irradiation defects, whereas at 800 °C, the density of cavities and dislocations reduced while the formation of M23C6 precipitates increased. These precipitates act as effective trapping sites for He and point defect, leading to cavity formation at the interfaces or within the precipitates. Moreover, increased irradiation fluence accelerates the co-evolution process, resulting in an increase in the density and size of both precipitates and cavities, ultimately leading to enhanced swelling. The {111} planes are favored interfaces between intragranular M23C6 precipitates and the matrix due to their minimal misfit, while the preferred interface planes between cavities with octahedral or cubo-octahedral shapes and the precipitate/matrix are also {111}, owing to their lower surface energy as well. The co-evolution of cavities and precipitates was found to influence mechanical properties, resulting in an irradiation hardening effect at lower fluences, while softening at higher fluences. This study provides novel insights into the degradation mechanisms of Ni-based alloys under coupling effect of He and high-temperature irradiation.

Mathematical study of a double-slope passive solar distiller with water heater condenser

In this article, the inevitable condensation losses from the back-side glass cover of a passive single-basin double-slope distiller (PSDD) were recovered in heating water inside a glass solar water heater (SWH) to produce hot water as an auxiliary product of the distiller. The transient thermal performance of the PSDD-SWH was mathematically modeled and compared to a conventional PSDD in actual weather circumstances. Compared to a conventional PSDD, the results revealed that the thermal efficiency of the PSDD-SWH increased by 18 % to 83 % during the day. In addition, increasing the water mass inside the water heater from 3 kg to 18 kg increased the thermal efficiency of the PSDD-SWH by about 50 % despite decreasing the total distillate by less than 1 %. Moreover, the thermal performance of the PSDD-SWH, in terms of distillate production, hot water temperature, and thermal efficiency boomed in hot climates with high solar irradiation and high ambient temperatures. Furthermore, insulating the glass covers of the PSDD-SWH during off-sun hours significantly enhanced the thermal performance of the PSDD-SWH.

Cloning and function characterization of a UDP-rhamnose synthase from Dendrobium huoshanense

UDP-rhamnose, which is synthesized under the catalysis by the rhamnose synthase(RHM), is an essential sugar donor for the synthesis of rhamnoside in plants. Based on the reported rhamnose synthase, this study screened one RHM gene(DhuRHM) from the localized gene database of Dendrobium huoshanense by sequence alignment. This gene was cloned, and then bioinformatics analysis and in vitro functional verification were carried out. The results revealed that DhuRHM had an open reading frame of 2 016 bp, encoding a protein with 671 residues, a molecular weight of 75.43 kDa, and a theoretical isoelectric point of 6.12. Subcellular localization analysis indicated that DhuRHM was located on the cell membrane. Multiple sequence alignments and the phylogenetic tree showed that DhuRHM possessed the characteristic domains(GxxGxxG/A and YxxxK) of the plant RHM family and presented high homology with the RHMs of other species. DhuRHM had the activity to catalyze the transformation of UDP-glucose into UDP-rhamnose. Furthermore, RT-qPCR results showcased that the expression level of DhuRHM in stems was higher than those in leaves and roots. Among four abiotic stress conditions(high temperature, low temperature, drought, and ultraviolet radiation) and MeJA treatment, ultraviolet radiation, low temperature, and high temperature significantly up-regulated the expression of DhuRHM. This study is the first to obtain a rhamnose synthase from D. huoshanense and identify its functions. The findings enrich the knowledge about the plant RHM family and provide a reference for the research on the UDP-rhamnose biosynthetic pathway in D. huoshanense and the responses of related metabolites to environmental stress.

Influence of Silicon-Based Photoelectric Material Spectral Characteristics on Radiation Spectroscopy Thermometry

To research the influence of the photoelectric response characteristics of radiation thermometry, a high-temperature blackbody radiation spectrum measurement experimental system is built by using the standard blackbody furnace, optical-fiber spectrometer with silicon-based photoelectric detection material. By setting different integration times of the spectrometer, the standard blackbody radiation spectrum measurement at different temperatures is carried out. The influence of the photoelectric response characteristics parameters is analyzed in detail. Therefore, the linear range between fitting band and spectral response intensity of radiation spectrum thermometry parameters is optimized. On this basis, through the standard blackbody radiation temperature measurement, the influence of the optimal parameter fitting band and the linear interval of spectral response intensity on the radiation temperature measurement results are verified. The influence of the mentioned photoelectric detection response characteristics on the spectral radiation thermometry has an important reference value for improving the accuracy of the spectral radiation thermometry.

He irradiation resistance performance in CrNiCo, CrFeNiCo, and CrFeMnNiCo multi-principal element alloys

In this study, the He irradiation resistance of CrFeMnNiCo high-entropy alloy (HEA) and CrNiCo and CrFeNiCo medium-entropy alloys (MEAs), which have better mechanical properties than HEAs, was investigated. Thin-film samples of CrFeMnNiCo, CrNiCo, and CrFeNiCo were irradiated with up to 2 × 1020 He/m2 of 5 keV ions at 673, 773, and 873 K, respectively. In all samples, He bubble formation was observed when irradiated at 1–3 × 1019 He/m2, which depended on the irradiation temperature. At low temperatures of 673 and 773 K, even when as the irradiation dose increased to 2 × 1020 He/m2, the differences in cavity swelling due to He bubble formation among the three alloys were not large. The relative resistance (degree) to cavity swelling for the three investigated alloys was as follows: CrNiCo MEA, CrFeMnNiCo HEA, and CrFeNiCo MEA. First-principles calculation results revealed that the formation of He-di-vacancy clusters was not possible in the CrFeNiCo MEA. This is believed to be the cause of the cavity swelling decrease in the CrFeNiCo MEA. In contrast, after 2 × 1020 He/m2 at 873 K, the cavity swelling of the CrNiCo and CrFeNiCo MEAs, especially CrNiCo, was approximately four times higher than that of the CrFeMnNiCo HEA. It is believed that the He irradiation resistance of the MEAs deteriorated because of element segregation owing to high–temperature irradiation.

Cost-Effective Thermomechanical Processing of Nanostructured Ferritic Alloys: Microstructure and Mechanical Properties Investigation.

Nanostructured ferritic alloys (NFAs), such as oxide-dispersion strengthened (ODS) alloys, play a vital role in advanced fission and fusion reactors, offering superior properties when incorporating nanoparticles under irradiation. Despite their importance, the high cost of mass-producing NFAs through mechanical milling presents a challenge. This study delves into the microstructure-mechanical property correlations of three NFAs produced using a novel, cost-effective approach combining severe plastic deformation (SPD) with the continuous thermomechanical processing (CTMP) method. Analysis using scanning electron microscopy (SEM)-electron backscatter diffraction (EBSD) revealed nano-grain structures and phases, while scanning transmission electron microscopy (STEM)-energy dispersive X-ray spectroscopy (EDS) quantified the size and density of Ti-N, Y-O, and Cr-O fine particles. Atom probe tomography (APT) further confirmed the absence of finer Y-O particles and characterized the chemical composition of the particles, suggesting possible nitride dispersion strengthening. Correlation of microstructure and mechanical testing results revealed that CTMP alloys, despite having lower nanoparticle densities, exhibit strength and ductility comparable to mechanically milled ODS alloys, likely due to their fine grain structure. However, higher nanoparticle densities may be necessary to prevent cavity swelling under high-temperature irradiation and helium gas production. Further enhancements in uniform nanoparticle distribution and increased sink strength are recommended to mitigate cavity swelling, advancing their suitability for nuclear applications.

Towards sustainable living in high radiation cold climates: A two-phase genetic algorithm approach for residential building optimization

The High Radiation Cold (HRC) region's unique climatic conditions, characterized by high solar radiation and low air temperatures, present distinct challenges for optimizing building climate responsiveness. In this study, residential building design is bifurcated into two phases: building geometry (Phase I) and envelope design (Phase II). In Phase II, we propose a heterogeneous vertical envelope (HVE) design to suit HRC climates. This research framework establishes multiple objectives: energy efficiency, indoor comfort, and economy. It aims to identify a balanced and sustainable design by optimizing various parameters and materials using a Multi-Objective Genetic Algorithms（MOGA). The results indicate enhanced building adaptability in HAV climates through MOGA. The optimal solution in phase I results in an annual heating load of 59.12 W/m2, 33.38 % annual indoor visual comfort hours and the adaptive model predicts 35.59 % annual comfort hours. Incorporating phase II optimization, the total annual energy demand is reduced by 34.42 % with an 11.35 % improvement in thermal comfort hours, culminating at 37.8 %.

Determination of thermal conductivity of phase pure 10H-SiC thin films by non-destructive Raman thermometry

The 10 H SiC thin films are potential candidates for devices that can be used in high temperature and high radiation environment. Measurement of thermal conductivity of thin films by a non-invasive method is very useful for such device fabrication. Micro-Raman method serves as an important tool in this aspect and is known as Raman thermometry. It utilises a steady-state heat transfer model in a semi-infinite half space and provides for an effective technique to measure thermal conductivity of films as a function of film thickness and laser spot size. This method has two limiting conditions i.e. thick film limit and thin film limit. The limiting conditions of this model was explored by simulating the model for different film thicknesses at constant laser spot size. 10H SiC films of three different thicknesses i.e. 104, 135 and 156 nm were chosen to validate the thin film limiting condition. Thermal conductivity of these thin films varied from 0.60 – 4.80 (Wm−1K−1).

Experiments on High-Temperature Irradiation of Li2ZrO3/MgLi2ZrO4 Ceramics by He2+ Ions

The key objective of this study is to determine the effect of interphase boundaries, the formation of which is caused by the variation of Li2ZrO3/MgLi2ZrO4 phases in lithium-containing ceramics based on lithium metazirconate, on the resistance to near-surface layer destruction processes associated with irradiation with He2+ ions. During the observation of the deformation effects that have an adverse impact on the volumetric swelling of the near-surface layers of ceramics, the thermal expansion factor caused by high-temperature irradiation was considered, simulating conditions as close as possible to the operating conditions of these materials as blankets for tritium propagation. During the studies conducted, it was established that an elevation in the contribution of MgLi2ZrO4 in the composition of ceramics leads to a rise in resistance to deformation swelling caused by structural distortions of the crystal lattice, due to a decrease in the effect of thermal expansion, alongside the presence of interphase boundaries. The established dependencies of the change in the hardness of the near-surface layer of the studied ceramics made it possible to establish the kinetics of softening caused by the deformation distortion of the crystalline structure, as well as to determine the relationship between volumetric swelling and softening (change in hardness) and a decrease in crack resistance (change in the value of resistance to single compression).