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Cu alloys have been widely used in the manufacture of liners because of their high density, good plasticity, and excellent thermal conductivity. In order to achieve excellent jet stability and penetration performance, it is necessary to further improve the mechanical properties of Cu-based liners. Nevertheless, the simultaneous enhancement of strength and ductility of the Cu alloys remains a huge challenge due to the strength–ductility trade-off phenomenon of metals/alloys. In this study, the microstructure evolution of rare earth Nd-modified Cu alloy and its effect on mechanical properties were investigated using OM, SEM, EBSD, and TEM techniques. The results show that the ultimate tensile strength (218 MPa) and elongation (50.7%) of sample 1 without Nd are the lowest. With increasing Nd content; the tensile strength and elongation of the samples increase; and the mechanical properties of sample 4 are the best, with a tensile strength of 278.6 MPa and elongation of 65.2%. In addition, with the increase in Nd content, not only is the grain size of the Cu-Nd alloy refined, but also the strength and plasticity are improved so that the strength–ductility trade-off phenomenon is improved. The strength improvement is mainly attributed to grain refinement strengthening, dispersion strengthening, and strain hardening. The increase in ductility is mainly related to the improvement of the microstructure heterogeneity by the Nd element. [ABSTRACT FROM AUTHOR]

• A numerical model for duct-ventilated embankments driven by temperature difference is developed. • The effects of duct structure on its cooling performance are analyzed. • Ducts can greatly reduce the effect of snow thermal insulation on the cooling performance of a crushed-rock layer. In pan-Arctic permafrost regions, longitudinal ventilation ducts are often installed in embankments to cool the underlying permafrost and thereby ensure road stability. However, the current design methods for embankments with longitudinal ventilation ducts (ED) normally simplify the conjugate heat transfer process between the duct wall and air in the duct. In this study, based on the chimney effect and the theory of fluid flow and heat transfer, we propose an improved numerical method for evaluating the cooling performance of the ED. Using this method, we conduct an assessment of the influences of duct configuration on the efficiency of ventilation duct cooling in winter. The results indicate that increasing the diameter of the duct and the height of the duct outlet can effectively improve the radial cooling range of the ventilation duct. However, the cooling performance of the ventilation duct becomes worse when the length of the duct is increased. To address the limited cooling performance of the ED, we design a crushed-rock interlayer embankment installed with longitudinal ventilation ducts (CED). It is found that the CED is more effective at maintaining the long-term thermal stability of the road in a typical pan-Arctic permafrost region when compared to the ED and the crushed-rock interlayer embankment. Furthermore, a cost analysis of the four different embankment designs reveals that the CED is a financially viable option for embankment construction in permafrost regions. [ABSTRACT FROM AUTHOR]

The effects of rare earth Ce on the microstructure and properties of cast pure copper were investigated through thermodynamic calculations, XRD analysis, mechanical testing, metallographic microscopy, and scanning electron microscopy (SEM). The experimental results demonstrate that the reaction between rare earth Ce and oxygen as well as sulfur in copper exhibits a significantly negative Gibbs free energy value, indicating a strong thermodynamic driving force for deoxidation and desulfurization reactions. Ce is capable of removing trace amounts of O and S from copper. Moreover, the maximum solid solubility of Ce in Cu falls within the range of 0.009% to 0.01%. Furthermore, Ce can refine columnar grains while enlarging equiaxed grains in as-cast copper. Upon the addition of rare earth Ce, the tensile strength increased by 8.45%, elongation increased by 12.1%, and microhardness rose from 73.5 HV to 81.2 HV—an increase of 10.5%. Overall, rare earth Ce has been found to enhance both the microstructure and mechanical properties of cast pure copper. [ABSTRACT FROM AUTHOR]

The degradation of permafrost caused by climate change and engineering disturbance significantly affects infrastructure stability and transportation safety. Two-phase closed thermosyphons (TPCTs) were widely used to tackle external disturbances by cooling the permafrost stratum in permafrost engineering. However, existing research mainly focuses on the thermal performance of TPCTs. To evaluate the spatiotemporal thermal-deformation characteristics of a composite embankment with L-shaped two-phase closed themosyphons (LTPCTs) on a permafrost slope, we built the first spatiotemporal thermal-deformation observation system for a permafrost embankment with LTPCTs and insulation along the Gonghe-Yushu Highway in the Qinghai-Tibet Plateau, as well as a contrast embankment only with insulation (as a control). The observation results during the first five-year service period indicate that: (1) The cooling performance of LTPCT is determined by the air temperature, and the exterior wall temperature at the top of the evaporator section is significantly affected by the surface ground; additionally, its maximum effective cooling scope is no more than 2.0 m; (2) The LTPCTs can effectively cool down the underlying permafrost in the middle of the composite embankment, and reduce the settlement of the centerline after the second service year; (3) The deformation in the middle of the composite embankment is mainly from the layer of −3.5 to −6.0 m under the bottom of the asphalt layer in the first three years; (4) The maximum settlement near the long sunny slope of the composite embankment can reach 4 times of that at the centerline, and the continuously increasing deformation difference along the cross section may cause longitudinal cracks of the embankment, and influence the traffic safety. Therefore, it is believed that the research results can promote acknowledge for the composite embankments with LTPCTs used in a permafrost slope. [ABSTRACT FROM AUTHOR]

Objective: In this study, we present our early outcomes of cyanoacrylate ablation (CA) versus endovenous laser ablation (EVLA) for the treatment of great saphenous vein (GSV) insufficiency in the Chinese mainland population. Methods: We retrospectively analyzed 108 patients (53 patients in the CA group and 55 patients in the EVLA group) with GSV insufficiency who were treated with CA and EVLA between May 2020 and May 2021. The Venous Clinical Severity Score and Aberdeen Varicose Vein Questionnaire were used to assess clinical symptoms and quality of life, respectively. Total closure rates and procedure-related adverse events were also recorded in both groups. Results: There was no significant difference between patients treated with CA or EVLA in terms of demographic and clinical characteristics. The average procedure time was 17 min in the CA group and 35 min in the EVLA group (p < 0.001). The CA group had lower pain scores during the procedure and 3 days afterward than the EVLA group (p < 0.001). At month 12, the CA group had a 90.4% closure rate, while the EVLA group had an 83.0% closure rate, with no significant difference between the two groups (p > 0.05). There was no significant difference in the Venous Clinical Severity Score or Aberdeen Varicose Vein Questionnaire score between the groups (p > 0.05). During follow-up, neither group experienced any significant adverse events, such as pulmonary embolism or deep venous thrombosis. The incidence of ecchymosis and paresthesia was significantly lower in the CA group than in the EVLA group (p < 0.05). Conclusions: Cyanoacrylate ablation has a high feasibility profile and is an effective approach to accomplish complete GSV target vein closure at early follow-up in the Chinese patients. Compared to EVLA, the improvement in quality-of-life outcomes is also sustained and similar, with less pain and fewer complications due to the absence of tumescence anesthesia and postprocedural compression stockings. [ABSTRACT FROM AUTHOR]

The energy industry is placing more and more emphasis on the need for effective and affordable electrocatalysts for hydrogen evolution reactions (HER). In this work, an iron-doped NiS/Ni(OH)2/CC composite material was synthesized by simple hydrothermal sulfurization processes of bimetallic Prussian blue analogue (PBAs) precursors grown in situ on three-dimensional (3D) Ni(OH)2 nanosheets. The overpotential can be 103 mV to attain current densities of 10 mA cm−2. The excellent catalytic activity of Fe-NiS/Ni(OH)2/CC is because of the unique 3D structure and the uniform doping of iron caused by the in situ growth of PBA, as well as the high conductivity of the self-supported electrode carbon cloth. [ABSTRACT FROM AUTHOR]

The gut microbiome plays a vital role in host ecological adaptation, especially dietary adaptations. Primates have evolved a variety of dietary and gut physiological structures that are useful to explore the role of the gut microbiome in host dietary adaptations. Here, we characterize gut microbiome transcriptional activity in ten fecal samples from primates with three different diets and compare the results to their previously reported metagenomic profile. Bacteria related to cellulose degradation, like Bacteroidaceae and Alcaligenaceae, were enriched and actively expressed in the gut microbiome of folivorous primates, and functional analysis revealed that the glycan biosynthesis and metabolic pathways were significantly active. In omnivorous primates, Helicobacteraceae, which promote lipid metabolism, were significantly enriched in expression, and activity and xenobiotic biodegradation and metabolism as well as lipid metabolism pathways were significantly active. In frugivorous primates, the abundance and activity of Elusimicrobiaceae, Neisseriaceae, and Succinivibrionaceae, which are associated with digestion of pectin and fructose, were significantly elevated, and the functional pathways involved in the endocrine system were significantly enriched. In conclusion, the gut microbiome contributes to host dietary adaptation by helping hosts digest the inaccessible nutrients in their specific diets. [ABSTRACT FROM AUTHOR]

Solar reflective coating (SRC) offers a method to reduce surface temperature without the need for additional energy consumption, making it highly applicable in permafrost regions. However, many SRCs with high solar reflectance are white, which can cause glare and not meet the aesthetic pavement requirements of high-grade highways. Herein, we developed two non-white SRCs (black and gray) designed to achieve low reflectance in the visible spectrum while maintaining high reflectance in the near-infrared region. We then evaluated the thermal performance of a white SRC, two non-white SRCs and asphalt (as a control) by analyzing surface temperature, ground temperature, and the heat flux between the soil and pavement in a permafrost region of the Qinghai-Tibet Plateau. The results showed that three SRCs reduced the annual mean surface temperature and surface temperature fluctuation compared to the asphalt. The white SRC exhibited annual heat release, whereas the non-white SRCs (black and gray) reduced heat absorption by 34.53% and 69.44%, respectively, compared to the asphalt. By directly reducing the heat absorption of asphalt, the non-white SRCs can potentially slow permafrost degradation beneath asphalt pavements. This study provides a theoretical foundation and technical support for applying non-white near-infrared SRC on high-grade highways in permafrost regions. [ABSTRACT FROM AUTHOR]

The asymmetric heat-water-deformation responses to solar radiation on sunny and shady slopes cause the failure of water conveyance canals in cold regions, threatening water, food, and ecological security. To investigate the influence of solar radiation on differential heat-water-deformation behaviors, a novel model test equipment incorporating solar radiation and freezing-thawing conditions was developed. A canal model was tested under different solar radiation intensities between slopes during freezing-thawing. Results show that solar radiation intensifies heat flux on the canal surface, increasing temperature while enhancing convective heat loss. Frozen soil phase change leads to solar energy storage in the sunny slope, causing a temperature difference between slopes. This leads to increased disparities in freezing depth, water content, deformation, and strain. Additionally, the disparities in freezing depth, deformation, and strain of both slopes are linearly related to the difference in daily solar radiation absorption. Under a 39.2 W/m2 intensity difference at −15 °C ambient temperature, the freezing depth, deformation, and strain of the shady slope can reach 1.4 times those of the sunny slope. Furthermore, the sunny slope has higher surface soil water content, potentially damaging the lining during thawing due to reduced freezing force. These findings enhance our understanding of canal failure mechanisms. • Develop a model test system incorporating freezing-thawing condition and solar radiation. • Test thermal transfer and heat-water-deformation responses of a canal under solar radiation. • Discuss the effect of solar radiation on the sunny-shady slope effect of a canal. • Provide recommendations for mitigating canal frost heave using solar radiation. [ABSTRACT FROM AUTHOR]

The crushed-rock layer (CRL) in permafrost regions frequently deteriorates due to aeolian sand, snow accumulation as well as vibrations induced by traffic loads. This degradation can adversely affect the thermal performance of crushed-rock embankments (CREs), potentially causing deviations from their designed specifications. Therefore, it is imperative to thoroughly investigate the thermal stability of CREs under conditions of CRL degradation. By utilizing the crushed-rock interlayer embankment (CRIE) as a representative case, this study employs numerical simulations to analyze six instances of crushed-rock interlayer (CRI) deterioration, employing a mathematical model incorporating adjusted thermal parameters specific to the CRIE. In addition, a novel methodology for quantitatively analyzing temperature distributions within permafrost embankments is employed to assess the results. The findings indicate that all embankment cases lose their cooling capacity on the underlying permafrost prior to the 35th service year. Therefore, mitigating the rate of CRI degradation is essential to preserving the integrity of its underlying permafrost throughout the entire lifespan of the CRIE. The results of this study contribute to the advancement of a theoretical framework for the construction of CRIEs with significant safety margins in permafrost regions. • An improved model of crushed-rock interlayer (CRI) embankments was proposed. • A quantitative method of permafrost embankment temperature contours was proposed. • Six extreme CRI degradation conditions were proposed. • The thermal stability changes of embankments due to CRI degradation were studied. [ABSTRACT FROM AUTHOR]

Previous RS5 (type 5 resistant starch) research has significantly broadened starch use and benefited society, yet the effects of the molecular weight of amylose on RS5 remain underexplored. In this study, amyloses with different molecular weights were complexed with caproic acid (C6), lauric acid (C12), and stearic acid (C18) to observe the effects of the molecular weight of amylose on the structure and in vitro digestive properties of RS5. Gel permeation chromatography revealed that the peak average molecular weight (Mp) values of high-amylose cornstarch NF-CGK (CGK), high-amylose cornstarch obtained via cornstarch via autoclave (high temperature and high pressure)-cooling combined pullulanase enzymatic hydrolysis (CTE), and high-amylose cornstarch NF-G370 (HCK) were 21,282, 171,537, and 188,084 before fatty acid complexation, respectively. Additionally, their weight average molecular weight (Mw) values of 32,429, 327,344, and 410,610 and hydrolysis rates of 58.12 %, 86.77 %, and 64.58 %, respectively. The hydrolysis rate of low-Mw amylose (GCK) complexes with fatty acids was lower than that of HCK and CTE starch–lipid complexes. However, HCK and CTE having similar molecular weights, there was no significant difference in the hydrolysis rate of starch–lipid complexes. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and complexing index analyses confirmed the formation of these complexes. This study proposed the mechanism of RS5 formation and provided guidance for its future development. [Display omitted] [ABSTRACT FROM AUTHOR]

For concrete used in severely cold regions such as the Qinghai-Tibet Plateau, the Northeast China, and the Arctic region, it will inevitably be subjected to the freeze-thaw (FT) cycles close to -40 ℃. However, the lowest temperatures of the conventional concrete FT cycle tests are not lower than -20 ℃. To investigate the differences in concrete damage between the conventional FT cycle circumstance and the severely cold FT cycle circumstance, there are two kinds of the FT cycle test circumstances in this study: -18 ℃ ∼ +5 ℃ (FTC-18) and -40 ℃ ∼ +5 ℃ (FTC-40). The results indicate that, under both FT cycle circumstances, the deterioration rate of concrete escalates as the increase in the FT cycle number. Based on numerical simulation, after the same FT cycle number and under the same stress, the quantity of cracks formed by the load inside the concrete under FTC-40 exceeds that under FTC-18. The results from multi-scale experiments and numerical simulation consistently show that the damage effect of FTC-40 on concrete is more significant than that of FTC-18. The reason for this is that at -40 ℃, more pore water freezes compared to -18 ℃. In addition, the FT damage constitutive models for concrete exposed to both FTC-18 and FTC-40 are developed. The stress-strain curves obtained from the theoretical models exhibit good alignment with the experimental stress-strain curves, thereby confirming the validity and accuracy of the established models. • The freeze-thaw cycles of −18 °C ∼ +5 °C and − 40 °C ∼ +5 °C were conducted on the concrete. • The damage of freeze-thaw cycles to concrete increases with the cycle number. • The discrete element numerical model of concrete was established. • The freeze-thaw damage constitutive model of concrete was derived. [ABSTRACT FROM AUTHOR]

• The effect of Nd element on the dynamic impact behavior of the Cu alloy was investigated. • The strengthening mechanism of the Cu alloy with different Nd contents was revealed. • The microstructure of Cu alloy during the dynamic impact was characterized. In this study, three kinds of Cu-Nd alloys were prepared. The effect of Nd content on the dynamic impact behavior of the Cu-Nd alloys and its strengthening mechanism were studied. The results show that during the dynamic impact process, nano-scale oxide particles are precipitated in the alloy matrix, and a large number of cracks are formed along the grain boundaries, and the formation of shear bands and thermal grooves are also observed in local areas. With the increase of Nd content, the compressive strength of the alloys increases significantly, the grain size is refined, the number of twins increases, the grooves are much deeper and the number of the precipitated nano-oxide particles also increase significantly. In addition, due to the refinement of the grain size, the crack length is reduced. The increase of the alloy strength is mainly attributed to the nano-scale oxide precipitation strengthening and grain refinement strengthening. [ABSTRACT FROM AUTHOR]

In the permafrost regions, the curing process of bored pile concrete is conducted under negative temperature. This curing condition significantly impedes the development and formation of the concrete performances. 1,2-propanediol (1,2-PPD) is widely recognized as an excellent refrigerant and deicing agent in industrial applications, but its utilization in concrete remains infrequent. To enhance the performances of bored pile concrete in permafrost regions, this study explored the influence mechanism of 1,2-PPD on the mortar performances subjected to the negative temperature curing condition. The results indicate that the addition of 1,2-PPD improves the compressive strength of the mortar samples at 7, 14, 21 and 28 days of curing, and the optimal content of 1,2-PPD is 0.5 %. Through the analysis of the results obtained from the thermogravimetric test and the hydration heat test using the dissolution heat method, it is determined that 0.5 % 1,2-PPD maximizes the hydration degree of cement, leading to increased production of hydration products and the denser pore structure in the mortar samples. After 28 days of curing, the mortar sample demonstrates the highest compressive strength, exhibiting the remarkable increase of 60.6 %. Additionally, the mortar sample presents the smallest rapid chloride ion migration coefficient and the optimal pore characteristics. • 1,2-propanediol is used in mortar cured under the negative temperature condition. • 1,2-propanediol can improve the hydration degree of cement. • The optimal content of 1,2-propanediol is 0.5 %. [ABSTRACT FROM AUTHOR]

Lined canals in cold regions often experience severe frost damage, posing a significant threat to the water supply safety. This paper proposes a modified analytical solution for the response of canal lining under soil frost heave, which is based on a Timoshenko beam on a Pasternak foundation considering tangential contact between the lining and frozen soil. This analytical solution can provide any solution using Timoshenko or Euler–Bernoulli beams on Pasternak or Winkler foundations with or without tangential contact. Then, the modified analytical solution, along with the traditional analytical solutions using Euler–Bernoulli beams on Winkle foundations, is compared against both model test and numerical simulation results. The modified analytical solution performs better than the traditional solution. Finally, the effects of foundation model, beam model, and tangential contact in simulating canal frost heave were discussed, and some measures to mitigate canal frost heave are proposed. The results show that solutions based on Winkler foundation overestimate frost heaves and tensile stresses of canal linings, and solutions without considering tangential contact only obtains overestimated frost heave. In addition, solutions based on Euler–Bernoulli beams underestimate frost heaves slightly and overestimate tensile stresses slightly. Therefore, the Pasternak foundation, Euler–Bernoulli beam, and tangential contact model can be used to simulate canal frost heave. The modified analytical solution directly uses field measurements of soil free frost heave to calculate canal frost heave, thereby enhancing result reliability. This analytical solution provides a simple method for canal frost heave design, and can be applied to frost heave analyses of flat and inclined structures. [Display omitted] • Propose analytical solution considering shear effects of the lining, frozen soil, and their tangential contact. • Perform model test and numerical simulation to verify the accuracy of the analytical solution. • Discuss the applicability of foundation and beam models on simulating canal frost heave. • Factors studied include the shear layer stiffness, and normal and tangential contact conditions. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the burden of kidney dysfunction (KD), assess socioeconomic inequalities, and project trends in the future. Data on deaths, disability-adjusted life years (DALYs), years lived with disability (YLDs), and years of life lost (YLLs) were from Global Burden of Disease Study 2019. The Joinpoint regression model was utilized to analyze the temporal trend by the annual percentage change (APC). The slope index and concentration index were employed to evaluate cross-country disparities. The future trend was predicted using an age-period-cohort analysis. In the past three decades, the death numbers of KD increased from 1,571,720 to 3,161,552, DALYs from 42,090,331 to 76,486,945, YLDs from 5,003,267 to 11,282,484, and YLLs from 37,087,065 to 65,204,461, respectively. The age-standardized rate (ASR) of deaths, DALYs, and YLLs exhibited a declining trend. The ASR of YLDs increased until 2017, then decreased. The slope index and concentration index for DALYs increased from 248.1 to 351.9 and from 40.70 to 57.8. In the future, the ASR of deaths, DALYs, YLDs, and YLLs will remain stable, while their numbers will continue to rise, except for YLLs. The disease burden of KD remained serious. Tailored interventions should be developed based on national contexts. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production rates have been measured from Al‐doped SrTiO3 with a range of controlled shapes and sizes using a high‐throughput parallelized and automated photochemical reactor. It is found that the photocatalytic reactivity is influenced by crystal shape and that crystals with a {1 1 0} to {1 0 0} surface area ratio between 1.3 and 1.8 yield more H2 than crystals with other ratios. Crystals with a {1 1 0}/{1 0 0} surface area ratio of 1.8 generate hydrogen at 550 μmol h−1 g−1 at pH 7, whereas crystals with only {1 0 0} facets exposed generate hydrogen at 300 μmol h−1 g−1 under the same condition. It is likely that the surface area ratio provides the appropriate balance between the photoanodic reaction on the {1 1 0} surface and the photocathodic reaction on the {1 0 0} surface. In the size range of 250–450 nm, larger crystals produce hydrogen at a rate of 400 μmol h−1 g−1 at pH 7, whereas smaller crystals only produce 200 μmol h−1 g−1, suggesting that the larger crystals reduce the rate of electron–hole recombination or back reaction and that the widths of the space charges within the crystal are comparable to the particle radius. [ABSTRACT FROM AUTHOR]

• We propose a method to determine the solar albedo of pavement and embankment slope surfaces. • The solar albedo characteristics of different embankment slopes were evaluated by the proposed method. • A structural solution to improve the thermal stability of permafrost embankment is tentatively proposed. • The applicability of different albedo measurement methods for slopes is analyzed. Roadways built in permafrost regions are more sensitive to the thermal disturbance caused by the natural environment and engineering construction activities. The construction of the embankment changes the albedo characteristics of the natural ground surfaces. Dark asphalt pavement absorbs a huge amount of solar radiation into the permafrost embankment, which leads to the thawing of frozen soil and freezing-thawing diseases of the embankment. Besides, the south-facing slope of the high-fill embankment is exposed to longer and stronger insolation than the north-facing slope annually. It gives rise to the thermal asymmetrical problem and differential settlement across the embankment. To solve above problems and further improve the thermal stability of permafrost embankment, we study the solar albedo characteristics of pavement and embankment slope surfaces in permafrost regions. In this study, an albedo measurement method is proposed for both pavement surface and slope surfaces. The method is validated by in-situ experiments and compared with traditional albedo measurement methods. Meanwhile, we measure the albedo values of the permafrost embankment surfaces along the G109 Highway in high latitude permafrost regions by using the proposed method. The results show that these embankment surfaces absorb a lot of solar radiation for a long time due to the low albedo. Comparing the measured results and remote sensing data, we carry out a comprehensive analysis of the albedo characteristics of permafrost embankment surfaces. Based on these findings, a preliminary solution is put forward to improve the thermal stability of permafrost embankment and decrease embankment diseases. [ABSTRACT FROM AUTHOR]

[Display omitted] Heterojunction can effectively improve oxygen evolution reaction (OER) activity by regulating the interfacial electronic structure of catalysts. However, p-p type heterojunction OER catalysts have obtained less attention, and the corresponding catalytic mechanisms are unclear either. Herein, the self-supported CoP-CoO p-p type heterojunction arrays are fabricated on carbon cloth substrate (CoP-CoO/CC). Band structure analysis shows that the formation of p-p heterojunction can drive the electrons from CoO to flow into CoP. This electronic modulation contributes to positively charged regions on the CoO and enhances the OH− adsorption during OER, proven by X-ray photoelectron spectroscopy and methanol molecular detection, respectively. As a result, the CoP-CoO/CC electrode only needs 210 mV overpotential to drive a current density of 10 mA cm−2 in an alkaline medium, superior to the most reported OER catalysts. Additionally, the CoP-CoO/CC also exhibits an ideal hydrogen evolution reaction response, and a water splitting system has been successfully constructed which can drive a 10 mA cm−2 within 1.65 V. This study supplies insight for catalytic origins p-p type heterojunctions OER catalyst, which provides a reference value for the efficient and reasonable design of heterojunction catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • LiNbO 3 /ZnS core–shell structure is firstly used for photocatalytic nitrate reduction. • ZnS provides surface active sites, while LiNbO 3 outputs plentiful photogenerated electrons to shell. • The unique core–shell structure dramatically improves the light-harvesting ability of the photocatalysts. Photocatalytic NO 3 – reduction in water has been regarded as a promising route due to its high efficiency and green feature. Several limiting factors, such as lack of catalytic sites, insufficient light collection, and spatial charge separation capacity photocatalytic denitrification, still need to be overcome for the practical applications. Herein, an innovative LiNbO 3 /ZnS heterojunction with a unilateral opening core–shell structure was constructed. ZnS was tightly anchored on the surface of LiNbO 3 by modified electrostatic self-assembly method. High nitrate removal rate (98.84%) and N 2 selectivity (98.92%) were achieved with a molar ratio of LiNbO 3 and ZnS of 1:5 (1:5L-ZS) using formic acid as a hole scavenge. The LiNbO 3 /ZnS degradation kinetics of NO 3 – was corresponding to the first-order kinetics equation. The nitrate removal rate and N 2 selectivity remained stable after three cycles in such photocatalytic NO 3 – reduction. The outstanding photocatalyst performance can be ascribed to the improved surface active sites, the well-matched band structure, and the unique core–shell structure. It provides an effective strategy for controllable fabrication of core–shell photocatalyst with strong light-harvesting ability and charge separation efficiency to enhance the removal rate of nitrate in water. [ABSTRACT FROM AUTHOR]

• The spectral reflectances of the CuO and TiO 2 blending coatings are studied. • The cooling performances of selected blending coatings are evaluated. • The spectral reflectance mechanisms of the blending coatings are explained. Reflective coating can be used as an effective technology to cool the pavements in cities and some special regions, e.g., permafrost regions. Given few reflective coatings are single-pigment dispersion, it is necessary to investigate the optical and thermal properties of coatings consisting of more than one pigments. Here we first take three types of particles, i.e., CuO microparticles (MPs), CuO nanoparticles (NPs) and TiO 2 nanoparticles (NPs), as pigments to make 12 types of epoxy-based blending coatings, then study their spectral reflectances and finally evaluate the cooling performances of eight selected coatings. Result shows that all the CuO and TiO 2 blending coatings are near-infrared reflective coatings, more specifically: (1) For a given total mass percentage of CuO and TiO 2 particles, with the increase of TiO 2 NPs, the spectral reflectance of the TiO 2 NPs and CuO NPs blending coating increases slightly, while that of TiO 2 NPs and CuO MPs increases largely; (2) For a given CuO particles mass percentage, the spectral reflectance of the CuO NPs and TiO 2 NPs blending coating is higher than that of the CuO MPs and TiO 2 NPs blending coating when the TiO 2 NPs mass percentage is lower than 15.88%; the situation will be reversed when the TiO 2 NPs mass percentage is equal or higher than 15.88%; (3) the cooling performances of these selected near-infrared coatings are found no matter under the summer or autumn meteorological condition. This study can provide insights and references for fabricating the near-infrared reflective blending coatings, thereby reducing the undesired pavement absorbed energy. [ABSTRACT FROM AUTHOR]

Direct Z-scheme heterojunction is a promising candidate for photocatalysts because it effectively separates the photogenerated electrons-hole pairs with strong redox capacity. In this paper, the MoSTe-MSi 2 N 4 (M = Mo, W) heterostructures are constructed, and their stability, electronic structures and photocatalytic performance are investigated. The results demonstrate that the absorption properties of heterojunctions are significantly better than that of monolayers in both visible and ultraviolet light regions. Expressly, heterojunctions have the direct Z-scheme charge transfer mechanism when S surface of MoSTe contacted with MSi 2 N 4 (namely S-M). Further calculation find that the S-M heterojunctions can perform stable photocatalytic water splitting in both acidic and neutral environments, and have better hydrogen evolution reaction. These theoretical predictions suggest that the MoSTe-MSi 2 N 4 heterostructures are high-performance photocatalysts for the preparation of hydrogen gas. [Display omitted] • Light absorption capacity of heterostructures is increased compared to monolayers. • Direct Z-scheme heterojunctions formed when S surface contacted with MSi 2 N 4. • Heterojunctions exhibit stability under uniaxial strain and acidic environments. • Heterojunctions improve the hydrogen production ability of monolayers. [ABSTRACT FROM AUTHOR]

In this paper, iron phthalocyanine nanowires on a nickel foam (FePc@NF) composite catalyst were prepared by a facile solvothermal approach. The catalyst showed good electrochemical oxygen evolution performance. In 1.0 M KOH electrolyte, 289 mV low overpotential and 49.9 mV dec−1 Tafel slope were seen at a current density of 10 mA cm−2. The excellent electrochemical performance comes from the homogeneous dispersion of phthalocyanine nanostructures on the surface of the nickel foam, which avoids the common agglomeration problem of such catalysts and provides a large number of active sites for the OER reaction, thus improving the catalytic performance of the system. [ABSTRACT FROM AUTHOR]

The stability and performance of loess infrastructure in cold regions are often challenged by seasonal freezing–thawing action. The action of the foundation loess is a complex thermo-hydro-mechanical coupling process, and it is crucial to understand this process for the loess infrastructure in cold regions. A series of controlled tests were conducted to observe the changes in temperature, moisture, and frost heave variations within loess samples under freezing–thawing, and the influences of cycle period, freezing–thawing amplitude, and cycle number on the thermo-hydro-mechanical behavior of loess were investigated. The results reveal that freeze–thaw cycles significantly affect the heat transfer, water migration, and deformation of the loess. The temperatures of sample at different heights periodically vary under freezing–thawing. Water is absorbed to the samples, which undergoes a rapid water intake stage, a water drained stage, and a slow water intake stage under freezing–thawing, resulting in moisture redistribution in loess. Loess undergoes frost heave, thaw settlement, and consolidation processes during freezing–thawing, and a slight wetting collapse may occur after several freezing–thawing cycles. Within the same cycle, frost heave is the largest while consolidation deformation is the smallest. Frost heave and consolidation deformation reach their maximum values at the second cycle, whereas thaw settlement reaches its maximum value during the second or third cycle. Each stage deformation increases with an extended cycle period and almost decreases as the freezing–thawing amplitude increases. Freeze–thaw cycles can induce wetting collapse of loess, resulting in negative residual deformation. Furthermore, the thermo-hydro-mechanical coupling process and the deformation mechanism of loess have been elucidated. These insights contribute to a more comprehensive understanding of the failure mechanisms in loess engineering in cold regions. [ABSTRACT FROM AUTHOR]

• The installing position of the LTPCT can affect its work performance and spatial heat control effect. • Based on the spatial heat control capacity of the LTPCTs, we obtained the optimal installing position. • The optimal installing position can effectively enlarge the cooling depth and reduce the ground temperature difference. The traditional design of TPCTs in embankment can cause differential frost heave due to the differential cooling effect in space. To enhance the control performance of the TPCTs, we numerically evaluated the influence of installing position on the spatial heat control, including the L-shaped TPCTs at shoulders, at slopes, and at toes. The results show that: (1) the position can affect the work performance of the L-shaped TPCTs. The annual accumulated power of the L-shaped TPCT reduces from 115.0 kW at shoulder to 101.2 kW at slope in the 20th year; (2) although the embankment with L-shaped TPCTs at shoulders has the minimum net annual heat absorption of 24.7 MJ, differential temperature exists for the shallow ground; (3) the L-shaped TPCTs at slopes can both reduce the spatial temperature difference and strengthen the cooling capacity for the deep permafrost. The maximum lateral cooling distance can reach 23.0 m; and (4) the cooling depth is weakened when the L-shaped TPCTs were installed at toes. Meanwhile, its cooling effect on the center section is insufficient due to the bimodal temperature distributions. Furthermore, it can cause slightly asymmetrical temperature distribution for the deep permafrost. Therefore, the installing position of L-shaped TPCT should be considered to develop its control performance in permafrost regions. [ABSTRACT FROM AUTHOR]

The effects of crystal orientation and ferroelectric domain structure on the photochemical reactivity of La 2 Ti 2 O 7 have been measured. Electron backscattered diffraction was used to determine the orientations of the surfaces of crystals in a ceramic specimen, piezo-force microscopy was used to determine the domain structure, and the photocathodic reduction of silver from an aqueous silver nitrate solution was used to evaluate the photochemical reactivity. The reactivity is greatest on (001) surfaces (this is the orientation of the layers in this (110) p layered perovskite structure) while surfaces perpendicular to this orientation have the least reactivity. Complex domain structures were observed within the grains, but they appeared to have no effect on the photocathodic reduction of silver, in contrast to previous observations on other ferroelectrics. La 2 Ti 2 O 7 is an example of a ferroelectric oxide in which the crystal orientation has a greater influence on the photochemical reactivity than polarization from the internal domain structure. [ABSTRACT FROM AUTHOR]

Key message: We constructed a homoeologous recombination-based bin map of wheat chromosome 7B, providing a unique physical framework for further study of chromosome 7B and its homoeologues in wheat and its relatives. Homoeologous recombination leads to the dissection and diversification of the wheat genome. Advances in genome sequencing and genotyping have dramatically improved the efficacy and throughput of homoeologous recombination-based genome studies and alien introgression in wheat and its relatives. In this study, we aimed to physically dissect and map wheat chromosome 7B by inducing meiotic recombination of chromosome 7B with its homoeologues 7E in Thinopyrum elongatum and 7S in Aegilops speltoides. The special genotypes, which were double monosomic for chromosomes 7B' + 7E' or 7B' + 7S' and homozygous for the ph1b mutant, were produced to enhance 7B − 7E and 7B − 7S recombination. Chromosome-specific DNA markers were developed and used to pre-screen the large recombination populations for 7B − 7E and 7B − 7S recombinants. The DNA marker-mediated preselections were verified by fluorescent genomic in situ hybridization (GISH). In total, 29 7B − 7E and 61 7B − 7S recombinants and multiple chromosome aberrations were recovered and delineated by GISH and the wheat 90 K SNP assay. Integrated GISH and SNP analysis of the recombinants physically mapped the recombination breakpoints and partitioned wheat chromosome 7B into 44 bins with 523 SNPs assigned within. A composite bin map was constructed for chromosome 7B, showing the bin size and physical distribution of SNPs. This provides a unique physical framework for further study of chromosome 7B and its homoeologues. In addition, the 7B − 7E and 7B − 7S recombinants extend the genetic variability of wheat chromosome 7B and represent useful germplasm for wheat breeding. Thereby, this genomics-enabled chromosome engineering approach facilitates wheat genome study and enriches the gene pool of wheat improvement. [ABSTRACT FROM AUTHOR]

• The length ratio of the TPCT can significantly affect its heat transfer efficiency. • There exists the best length ratio for the TPCT with specific inclination angle. • The best length ratio changes with the inclination angle and inner diameter. Two-phase closed thermosyphons (TPCTs) have been widely used in solar energy utilization. The work presents an optimization of the TPCT used in cooling foundation in permafrost regions. A series of experiments under negative temperature conditions were conducted to investigate the effect of length ratios (LRs, length ratio of the evaporator section to the condenser section) on the cooling performance of the TPCT. Experimental results show that there exists a best LR for each angle, and it varies with the inclination angle. As an example, for the TPCT with 5.0-cm inner diameter, the maximum efficiency can be decreased by 17.3% for the TPCT with the LR of 1.00 compared with the TPCT with the best LR of 1.65. Under the best LR, the efficiency can be raised by 30.2% for the TPCT with the inclination angle of 20° compared with that of 90°. Besides, the best LR also changes with the pipe inner diameter, e.g. the best LR varies from 1.65 to 1.27 when the inner diameter changed from 5.0 cm to 8.1 cm. The results suggest that the equivalent length of the evaporator section should be appropriately lengthened to enhance the cooling performance of TPCTs in permafrost engineering. [ABSTRACT FROM AUTHOR]

In bacteria, the truncated forms of mRNAs, which usually lack a stop codon, are occasionally generated by premature termination of gene transcription and/or endo- or exonucleolytic cleavage events. Ribosomes proceeding on these molecules stall at the 3′ end of the chain and are rescued by a widely distributed mechanism known as trans-translation, which includes two essential elements, ssrA RNA (a special RNA) and SmpB (a small protein). Through this mechanism, the polypeptides translated from truncated mRNAs are marked by a short peptide, known as SsrA tag, at their C-termini and directed to the specific endogenous proteases for C-terminal proteolysis. Based on the deep understanding of the SsrA tagging and degradation mechanisms, recently a series of SsrA-based genetic tools have been developed for gene regulation on the level of post-translation. They are successfully applied for controllable regulation of biological circuits in bacteria. In the present article, we systematically summarize the history, structural characteristics, and functional mechanisms of the SsrA tagging and degrading machineries, as well as their technical uses and limitations. Key Points • SsrA system plays an important role in ribosome rescue in bacteria. • SsrA-based genetic tools are useful for controlling protein levels and activities. [ABSTRACT FROM AUTHOR]

• SiO 2 -TiO 2 composite powders are constructed under milder conditions. • Submicron-sized Ti-rich MWW is prepared via mechanochemical dry gel conversion (MDGC). • Ti-MWW-MDGC improves catalytic activity remarkably than Ti-MWW-DGC. • MDGC route is a promising approach to green synthesis of highly active zeolites. In this research, a novel green mechanochemical dry gel conversion method (MDGC) is reported to obtain submicron-sized Ti-rich MWW zeolite. First, titanium and silica sources were milled under milder conditions in a planetary ball mill to construct the uniform SiO 2 -TiO 2 composite powders with higher Ti contents. Subsequently, submicron-sized Ti-rich MWW zeolite powder was prepared via dry gel conversion (DGC) route using the obtained composite under mixed steam environment consisting of water and piperidine. The physicochemical properties of the SiO 2 -TiO 2 composites before and after calcination and corresponding Ti-MWW-MDGC were investigated by XRD, UV–Vis, FT-IR, SEM, XRF, and N 2 absorption-desorption. Moreover, Ti-MWW (30)-MDGC exhibited a superior catalytic activity during epoxidation with H 2 O 2 compared with the traditional DGC method, and the conversion of 1-hexene increased from 4.2% to 26.3%. The MDGC method is a promising approach for the green production of various zeolites with higher heteroatom contents, such as TS-1, Ti-Beta and Sn-MWW, etc. [ABSTRACT FROM AUTHOR]

Key message: We performed homoeologous recombination-based partitioning and physical mapping of wheat chromosome 3B and Th. elongatum chromosome 3E, providing a unique physical framework of this homoeologous pair for genome studies. The wheat (Triticum aestivum, 2n = 6x = 42, AABBDD) and Thinopyrum elongatum (2n = 2x = 14, EE) genomes can be differentiated from each other by fluorescent genomic in situ hybridization (FGISH) as well as molecular markers. This has facilitated homoeologous recombination-based partitioning and engineering of their genomes for physical mapping and alien introgression. Here, we constructed a special wheat genotype, which was double monosomic for wheat chromosome 3B and Th. elongatum chromosome 3E and homozygous for the ph1b mutant, to induce 3B–3E homoeologous recombination. Totally, 81 3B–3E recombinants were recovered and detected in the primary, secondary, and tertiary homoeologous recombination cycles by FGISH. Comparing to the primary recombination, the secondary and tertiary recombination shifted toward the proximal regions due to the increase in homology between the pairing partners. The 3B–3E recombinants were genotyped by high-throughput wheat 90-K single nucleotide polymorphism (SNP) arrays and their recombination breakpoints physically mapped based on the FGISH patterns and SNP results. The 3B–3E recombination physically partitioned chromosome 3B into 38 bins, and 429 SNPs were assigned to the distinct bins. Integrative analysis of FGISH and SNP results led to the construction of a composite bin map for chromosome 3B. Additionally, we developed 22 SNP-derived semi-thermal asymmetric reverse PCR markers specific for chromosome 3E and constructed a comparative map of homoeologous chromosomes 3E, 3B, 3A, and 3D. In summary, this work provides a unique physical framework for further studies of the 3B–3E homoeologous pair and diversifies the wheat genome for wheat improvement. [ABSTRACT FROM AUTHOR]

In this study, the variations of the temperatures and volumetric unfrozen water contents for two fine-grained soils (i.e., silty clay and silt) with high degrees of saturation during a freezing–thawing process were experimentally studied. Experimental results show that for the two soils, the supercooling phenomenon only happens in the early stage of freezing process, and the supercooling temperature and its duration of the silty clay are both larger than those of the silt under similar temperatures; furthermore, the hysteresis effect of volumetric unfrozen water content exists during the whole freezing–thawing process, and the maximum hysteresis levels both occur at the soil freezing points; however, the maximum value of the hysteresis level of the silt is larger than that of the silty clay. [ABSTRACT FROM AUTHOR]

Microsteel pipe piles are widely used in excavation support owing to their excellent bearing capacity, flexural rigidity, construction speed, and adaptability. In this study based on a project in soil-rock layers in Qingdao, China, a new type of support combining microsteel pipe piles mounted in cement-soil piles and anchors was adopted and studied. The inner force change laws and bearing capacity of microsteel pipe piles were discussed through in situ stress measurement and laboratory antibending tests on three microsteel pipe piles. It was found that the bending moment of the piles gradually increased with the foundation excavation and maximized at the pile head. The bending moment was larger at the upper and smaller at the lower part along the depth direction, indicating it is reasonable to design and calculate microsteel pipe piles by the pile-anchor system. The variation law of the foundation pit displacement with the excavation depth was monitored. The horizontal displacement of the foundation pit is the maximum at the base top, which is 6.5 mm. The flexural strength of the miniature steel tube pile after grouting is 40% higher than that of the miniature steel tube pile without grouting. It was indicated that the grouting microsteel pipe piles could be implanted in cement-soil piles, which improved the flexural rigidity of cement-soil piles and limited the deformation of foundation pits. This study provides reference for the design and construction of soil-rock foundation pit supporting projects. At the same time, it provides reference for the application of miniature steel pipe piles in other fields. [ABSTRACT FROM AUTHOR]

Diffusion limitation caused by microporous molecular sieves has always been a bottleneck problem in liquid phase epoxidation. In this study, several different carbon sources were used as hard templates to prepare hierarchically porous zeolite Ti-MWW (cTi-MWW) successfully. Compared with conventional Ti-MWW, cTi-MWW has an additional hierarchically porous structure and abundant pore structure distribution. Especially, the cTi-MWW prepared with polyethylene glycol1540 (PEG) as the hard template not only has a multiple hierarchically porous structure, but also exhibits small crystal size and good hydrophobicity properties studied by TEM and in situ FT-IR. At the same time, the cTi-MWW prepared with PEG exhibits better activity than the conventional Ti-MWW in the selective epoxidation reaction of allyl alcohol (AAL) with H2O2 as oxidant and the conversion is improved by 11% (Si/Ti = 20). And a higher efficiency and longer catalyst life in fixed-bed catalytic reactor were exhibited by using cTi-MWWPEG as catalyst. The physicochemical properties of cTi-MWW prepared with different hard templates were systematically studied by SEM, XPS, UV–Vis, XRD and N2 absorption–desorption techniques. This method is effective for the synthesis of cTi-MWW and significant for the preparation of hierarchically porous zeolites in industrial production. A hierarchically porous zeolite Ti-MWW prepared with different hard templates successfully. With the hierarchically porous structure, which have better adsorption, diffusion, and reactivity in liquid phase epoxidation, thus improving the catalytic activity. Especially, the hierarchically porous zeolite Ti-MWW prepared with polyethylene glycol exhibits small crystal size and good hydrophobicity properties. [ABSTRACT FROM AUTHOR]

• A method was developed to measure the solar albedo of rough surface layers with large particle sizes. • The albedo of rough surface layers was theoretically studied by the discrete-particle model. • The albedo of rough surface layers was mainly affected by solar conditions and particle properties. • The methods could be used to measure and calculate the albedo of crushed-rock layers or gravel piles. Albedo is an important parameter for many research fields, including solar energy, building energy conservation, road engineering, regional and global climate, environmental protection, and other fields. The solar albedo of rough surface is always lower than the reflectance of homogeneous and flat surface due to the irregular and nonuniform surface properties. It is difficult to determine the solar albedo of rough surface in laboratory, especially for the surface with large particle sizes or cavities. Here a method was developed to measure the solar albedo of rough surface layers based on discrete-particle model in consideration of particle sizes, diurnal variations, and solar and season conditions. Besides, the solar albedo was theoretically studied by the discrete-particle model with and without cavities, which shows good performance. The relationship between the solar albedo of rough surface and the reflectance of flat surface was also studied. This developed methods can be applied to many engineering fields, such as the crushed-rock layers of embankments in permafrost regions and the cool roofing of buildings in tropical regions. The results also showed that the rough surfaces with higher reflective coatings can increase the solar albedo with greater values, which may be expected to raise the cooling performance of above engineering applications. [ABSTRACT FROM AUTHOR]

Genetic recombination is the major mechanism and basis of genetic diversity and crop improvement. Recombination typically occurs between homologous chromosomes. In wheat, however, it can also occur between homoeologous chromosomes if a functional Ph1 (Pairing homoeologous-1) locus is absent (ph1b). Recently, the genes for soft kernel trait on the distal 5DS chromosome of common wheat were transferred into chromosome 5BS of durum wheat through ph1b-mediated recombination. Several independent 5DS–5BS recombination lines carrying the 5DS translocation were obtained. However, the specific size of the translocation and region where the translocation breakpoint occurred was not determined for any of the lines. In the present study, four independent 5DS–5BS recombination lines were investigated and the translocation breakpoints were fine-mapped and sequenced. All the analyzed lines lost a 5BS fragment of ~ 20,742,425 bp and gained a 5DS fragment of ~ 28,163,252 bp. The recombination breakpoint in each line was located within a predicted gene in a conserved 39 bp region, suggesting the presence of a recombination hotspot. The information obtained was then used to develop a KASP marker diagnostic for the 5DS–5BS translocation. Finally, a subset of the soft durum wheat lines exhibiting varying degrees of kernel hardness was analyzed through genomic in situ hybridization (GISH) and scanning electron microscopy (SEM). From both the GISH and SEM analyses no major differences were detected among the lines, indicating that factors other than ph1b-mediated recombination or endosperm morphology were responsible for the variation in kernel hardness. [ABSTRACT FROM AUTHOR]

A vision-based target-following guider for mobile robot is presented in this paper. It consists of three parts: the visual tracking part; the target redetection part; and the visual servo part. In the visual tracking part, the target contour band is proposed for irregular sampling, which can improve the performance of the correlation filter-based methods. In the target redetection part, potential targets are searched by an offline trained detector. Then an online training module is used to determine the real target and achieve accurate positioning. The interaction matrix of point features is used in the visual servo part for motion control to maintain the relative pose between the target and the robot. The visual tracking part and the target redetection part are tested respectively on many videos, which proved to work well. To show the effectiveness of our method, some state-of-the-art methods are also tested. The target-following guider is evaluated on mobile robots. In our experiments, the robot can robustly follow the human target over a long distance, which strongly proved the validity of our target-following guider. [ABSTRACT FROM AUTHOR]

In the quest to improve thermal regulation within permafrost embankments, the permafrost thermosyphons equipped with horizontal evaporators remains underexplored in scholarly discourse in open. This study delineates the design and numerical evaluation of a pressure-driven two-phase closed thermosyphon (PD-TPCT), featuring a horizontal evaporator exceeding 100 m. A half-theory heat transfer model, borne from a synergy of monitoring data and the thermal resistance method, was derived from an outdoor experimentation. Considering the growing global focus on the sustainable development of the Arctic and the Third Pole, we employ this heat transfer model to analyze the long-term thermal stabilities of a PD-TPCT embankment, a PD-TPCT embankment with insulated boards, and an unprotected embankment (as a control) in the Siberian Arctic (SA) and Qinghai-Tibet Plateau (QTP). This study reveals that the horizontal installation of the evaporator can mitigate the shady-sunny slope effect and improve the thermal stability of the underlying permafrost. The SA's climate allows the PD-TPCT embankment to protect permafrost for 50 years, while in the QTP, the PD-TPCT embankment with insulated boards is needed for the same protection. The insights garnered herein offer references to both the theoretical exploration and pragmatic implementation of advanced thermosyphon with ultra-long horizontal evaporators. [ABSTRACT FROM AUTHOR]

In the quest to improve thermal regulation within permafrost embankments, the permafrost thermosyphons equipped with horizontal evaporators remains underexplored in scholarly discourse in open. This study delineates the design and numerical evaluation of a pressure-driven two-phase closed thermosyphon (PD-TPCT), featuring a horizontal evaporator exceeding 100 m. A half-theory heat transfer model, borne from a synergy of monitoring data and the thermal resistance method, was derived from an outdoor experimentation. Considering the growing global focus on the sustainable development of the Arctic and the Third Pole, we employ this heat transfer model to analyze the long-term thermal stabilities of a PD-TPCT embankment, a PD-TPCT embankment with insulated boards, and an unprotected embankment (as a control) in the Siberian Arctic (SA) and Qinghai-Tibet Plateau (QTP). This study reveals that the horizontal installation of the evaporator can mitigate the shady-sunny slope effect and improve the thermal stability of the underlying permafrost. The SA's climate allows the PD-TPCT embankment to protect permafrost for 50 years, while in the QTP, the PD-TPCT embankment with insulated boards is needed for the same protection. The insights garnered herein offer references to both the theoretical exploration and pragmatic implementation of advanced thermosyphon with ultra-long horizontal evaporators. [ABSTRACT FROM AUTHOR]

• We develop a new fractal capillary model accounting for the hysteresis effect. • The immobile water in the pores of frozen soil is considered in the prediction model. • The immobile water has a significant influence on the hydraulic conductivity at lower saturation. • The proposed fractal model can be simplified to a power function. The hydraulic conductivity of frozen soil is crucial for predicting water migration and frozen heave. Many models have been proposed to estimate the hydraulic conductivity, which involves factors such as unfrozen water content, specific surface area, grain size distribution, and pore size distribution. However, the bottleneck effect on the hysteresis of unfrozen water has not been adequately considered. This study proposed a hydraulic conductivity model based on the fractal theory by assuming the capillary tubes with a pore throat. Subsequently, the hydraulic conductivity was expressed as the product of the saturated and relative hydraulic conductivity, both of which can be determined from the microscopic fractal characteristics. Finally, the proposed model was verified using the experimental data and existing models, and a sensitivity analysis of the relative hydraulic conductivity was conducted. The validation showed that the predicted results agree well with the experimental data. Meanwhile, the proposed model can better describe the hysteresis effect of unfrozen water content during the freezing-thawing process than other commonly used models. Relative hydraulic conductivity is sensitive to pore structure characteristics and unfrozen water content. Immobile water saturation evidently influenced the relative hydraulic conductivity when it reached 0.7. The proposed model can be simplified as a power function in which the exponent can be calculated using the fractal dimension. The results help simulate the dynamic process of unfrozen water in frozen soil and may help understand the complex mechanisms of hysteresis and transport processes in frozen soil. [ABSTRACT FROM AUTHOR]

[Display omitted] • TiA 2 P 4 monolayers exhibit excellent electron and lithium/sodium ion transport performances. • High theoretical capacities prove that TiA 2 P 4 monolayers are potential electrode materials for SIBs. • Revealed the reason why TiGe 2 P 4 is more suitable as electrode material for SIBs compared to LIBs. Two-dimensional (2D) materials have shown excellent application prospects in energy storage technologies due to the extraordinary physical and chemical properties. In this work, TiA 2 P 4 (A = Si or Ge) monolayers, that members of MA 2 Z 4 family, are selected as electrode materials for lithium/sodium-ion batteries. Their structural stabilities, mechanical properties, electronic structures, and energy storage performances are investigated by using first-principles calculations. Satisfactorily, TiA 2 P 4 monolayers have good thermodynamic stability and mechanical properties. Meanwhile, low diffusion barriers, suitable open circuit voltages and significant theoretical capacities prove that TiA 2 P 4 are suitable electrode materials for Li/Na storage, except for TiGe 2 P 4 that lack the ability to store lithium. The theoretical capacity of TiSi 2 P 4 monolayer is up to 470.33/705.50 mA h g−1 for Li/Na storage, and that of TiGe 2 P 4 monolayer is 507.24 mA h g−1 for Na-ions, which are better than many metal-like 2D layered materials. Our research indicates that both of TiA 2 P 4 are potential electrode material for sodium-ion batteries, and inspire the future design of other MA 2 Z 4 family in energy storage technologies. [ABSTRACT FROM AUTHOR]

Currently, the lowest temperature for the conventional freeze-thaw (FT) cycles tests of concrete are usually not lower than −20 °C. However, for concrete structures in severely cold regions, the winter temperature is below −20 °C. Compared with the conventional FT cycle test condition, concrete in severely cold regions is bound to suffer more serious FT deterioration, and it is necessary to improve the frost resistance of concrete in severely cold regions. To obtain the influence effect of nano-silica (NS) on the frost resistance of concrete in severely cold regions, a series of multi-scale tests were performed on the concrete added with 2% NS under the FT cycles of −40 °C ∼ +5 °C, as well as the concrete without NS (as a control). The results show that 2% NS can enhance the frost resistance of the concrete in severely cold regions. Namely, when the FT cycle number is the same, the performances of the concrete added with 2% NS are better than those without NS. Meanwhile, the performances of the concrete added with 2% NS after 200 FT cycles are still better than those without NS after only 100 FT cycles. • The freeze-thaw cycles of −40 °C ∼ +5 °C were conducted on the concrete. • The damage of freeze-thaw cycles to concrete increases with the number of cycles. • 2% nano-silica can improve the frost resistance of concrete in severely cold regions. [ABSTRACT FROM AUTHOR]

Seasonally frozen soil (SFS) is a critical component of the Cryosphere, and its heat-moisture-deformation characteristics during freeze-thaw processes greatly affect ecosystems, climate, and infrastructure stability. The influence of solar radiation and underlying surface colors on heat exchange between the atmosphere and soil, and SFS development, remains incompletely understood. A unidirectional freezing-thawing test system that considers solar radiation was developed. Subsequently, soil unidirectional freezing-thawing tests were conducted under varying solar radiation intensities and surface colors, and variations in heat flux, temperature, water content, and deformation were monitored. Finally, the effects of solar radiation and surface color on surface thermal response and soil heat-moisture-deformation behaviors were discussed. The results show that solar radiation and high-absorptivity surfaces can increase surface heat flux and convective heat flux, and linearly raise surface temperature. The small heat flux difference at night under different conditions indicates that soil ice-water phase change effectively stores solar energy, slowing down freezing depth development and delaying rapid and stable frost heave onset, ultimately reducing frost heave. Solar radiation causes a significant temperature increase during initial freezing and melting periods, yet its effect decreases notably in other freezing periods. Soil heat-water-deformation characteristics fluctuate due to solar radiation and diurnal soil freeze-thaw cycles exhibit cumulative water migration. Daily maximum solar radiation of 168 W/m2 and 308 W/m2 can cause heat-moisture fluctuations in SFS at depths of 6 cm and 11 cm, respectively. The research findings offer valuable insights into the formation, development, and use of solar radiation to mitigate frost heave in SFS. • Develop a unidirectional freezing-thawing test system that considers solar radiation. • Test freeze-thaw responses of frozen soil under solar radiation and surface color. • Discuss effects of the above factors on soil heat-moisture-deformation behaviors. [ABSTRACT FROM AUTHOR]

In this study, a series of freezing experiments were carried out to investigate the changes of volumetric unfrozen water contents in freezing soils. The experimental results show that the soil type and the initial volumetric water content have significant effect on the freezing point and volumetric unfrozen water content of freezing soils. On the base of the experimental results and the previous researches, a new model was developed to describe the changes of the volumetric unfrozen water contents in freezing soils. The developed model was validated by comparing the calculated results against the experimental ones. [ABSTRACT FROM AUTHOR]

How to effectively release excess ground heat to cool permafrost by using renewable ambient cool energy is an important issue because many environmental and engineering problems are associated with permafrost degradation. Two-phase closed thermosyphons (TPCTs) are widely used in many heat transfer applications. In this paper, a field experiment was conducted to evaluate the cooling performance of an air-L-shaped TPCT-ground (ALTG) cooling system used in permafrost embankments. We then developed a coupled model to describe the energy process of the ALTG cooling system, including the coupled ALTG heat transfer and the heat conduction with phase change for the permafrost ground. The model was validated by the field experiment. Both experimental and numerical results indicate that the cooling system can improve the heat releasing from ground to atmosphere, especially in the first four years. Finally, an improved ALTG system was proposed to enhance the absorption of ambient cool energy for a wider high-grade highway based on series of numerical simulations. Simulation results showed that the improved system could sufficiently extend the horizontal cooling extent under the embankment. This specially designed ALTG system will contribute to the control of ground heat using ambient cool energy in cold regions. • The air-L-shaped TPCT-ground (ALTG) system can enhance the heat-release process from ground to ambient. • Field experiments show that the cooling performance of the ALTG system is the most significant in the first four years. • A developed model is established to describe the energy process of the ALTG cooling system. • An improved ALTG system is proposed to enhance the absorption of ambient cool energy for a wider embankment. [ABSTRACT FROM AUTHOR]

Abstract Hydro-thermal properties of permafrost and its distribution are sensitive to climate changes and human activities. Accurate and reasonable prediction on aforementioned information is important for eco-environment construction and vital infrastructures development. To model the current and future states of permafrost, it is a key challenge to effectively determine the upper hydro-thermal boundary conditions for permafrost models under changing climate and different underlying surfaces at proper spatial and temporal scales. An approach, combined regional climate downscaling method with model output statistics method, was developed to produce a time series of air temperature, surface temperatures, and surface unfrozen water contents for different underlying surfaces. It provided various climate and surface parameters at a spatial scale on the order of 102 m2 for engineering designs, which was used to predict boundary conditions under possible climate scenarios. The predicted and simulated models were calibrated and validated by the monitored data at an experimental site in Chumar, China, close to the Qinghai-Tibet Railway and the Qinghai-Tibet Highway. Results show that the multiple linear regression model (MLRM) can predict the current states and future changes of upper hydro-thermal boundary conditions for permafrost while the original states of natural surface are modified by natural or human factors on the condition of complicated climatic and complex topography regions. The statistical regression model (SRM) based on the outputs of regional climate model (RCM) and MLRM provides a simple method for the convenience of numerical calculation. These results also indicate the possible applications to other areas and situations. Graphical abstract Unlabelled Image Highlights • The hydro-thermal boundary conditions were modeled at different underlying surfaces for permafrost engineering. • The regional climate downscaling method was combined with multiple linear regression method in the study. • The predicted and simulated models were calibrated and validated by the monitored data. • The developed approach was compared with the other methods for predicting hydro-thermal boundary conditions. [ABSTRACT FROM AUTHOR]

Abstract The hydro-thermal properties of the ground affect the thermal regimes and surface energy balances. A field experiment in the Qinghai-Tibet Plateau was carried out to analyze the hydro-thermal boundaries, and the variations of the ground temperatures, volumetric unfrozen water contents and matric suctions for different surfaces (i.e., asphalt surface, concrete surface and natural gravel surface). The results show that the asphalt surface significantly changes the permafrost table and ground temperature. The mean annual temperature under the asphalt surface is 2.40 °C higher than that under the concrete surface, and 2.77 °C higher than that under the natural gravel surface. Therefore, the permafrost table under the asphalt surface is deeper than that under the natural gravel and concrete surfaces. In addition, the freezing and thawing processes of the ground under different surfaces are significantly different. Moreover, the volumetric unfrozen water content changes quickly near the ice-water phase transition zone, while the matric suction seldom changes until the volumetric unfrozen water reaches a certain value during the cold seasons, and the volumetric unfrozen water content dramatically changes due to the rainfall during the warm seasons. Furthermore, the volumetric unfrozen water content first decreases, and then increases with depth in the cross sections of the embankments during the cold seasons. The minimum volumetric unfrozen water content lies at the depth of 0.40 m for the natural gravel surface, and 0.90 m for the asphalt and concrete surfaces. Highlights • The hydro-thermal boundaries for different surfaces were studied. • The variations of the ground temperatures, volumetric unfrozen water contents and matric suctions under different surfaces were analyzed. • The freezing and thawing processes of the ground under different surfaces were significantly different. [ABSTRACT FROM AUTHOR]

Abstract Some environmental and engineering problems are associated with permafrost thaw or degradation due to the releasing of CO 2 , the reducing of soil strength and the change of hydrologic processes. How to control the geothermal to approach these problems in cold regions is an important issue. Two-phase closed thermosyphons (TPCTs) are simple and efficient energy exchangers that are used in low-temperature refrigeration systems. In this study, a series of experiments were carried out to explore the geotemperature control process of a TPCT in an air-TPCT-soil system by storing renewable ambient cool energy. To enhance the control efficiency of the TPCT, we considered different operating conditions, with inclination angles of 90°, 70°, and 50°. The results indicate that the TPCT can cool the surrounding soil by selectively capturing the ambient energy due to its thermal semi-conductor effect. The inclination angle can change the efficiency of the TPCT, which should be accounted in engineering design. Under the experimental conditions, the geotemperature control efficiency of the TPCT with an inclination angle of approximately 70° was the optimal. The results of this study could provide a basis for the design of TPCTs used in cool energy utilization and other energy storage applications. Highlights • Two-phase closed thermosyphons (TPCTs) are used to store the renewable ambient cool energy in natural ground. • An air-TPCT-soil model test is performed to simulate the geothermal control process of inclined TPCT in cold regions. • Stored cool energy can effectively control the geotemperature in warm seasons. • The geothermal control capacity varies with inclined angles. • The optimal control efficiency of the TPCT are analyzed at different operating conditions. [ABSTRACT FROM AUTHOR]

Abstract Crushed-rock layers have been widely used to cool subgrades in permafrost regions. The convective cooling effect of crushed-rock layers depends not only on the cavities of the layers but also the outmost skin temperature, which is mainly regulated by the solar absorption. Here we experimentally studied the solar reflectance of crushed-rock layers with mean particle sizes of 0.9 cm, 1.5 cm, 2.2 cm, 3.5 cm, 5.4 cm, 8.4 cm, 11.8 cm, 17.3 cm and 26.4 cm, respectively. The experimental results indicate that the solar reflectance of the crushed-rock layers firstly decreases, and then increases with the mean particle size. It is found that the crushed-rock layer with a mean particle size of 5.4 cm reflects the least sunlight. The theoretical analysis indicates that a crushed rock layer absorbs more sunlight as the cavity ratio increases and as the mean intersection angle of crushed-rock surfaces decreases. Our findings imply that the solar reflectance of a crushed-rock layer can be raised by reducing the surface cavity ratio of the crushed-rock layer and/or flattening the crushed-rock layer surface; however, the surface cavity ratio of the crushed-rock layers and the mean intersection angle of the crushed-rock surfaces are uncertain because the crushed-rocks with different shapes were randomly poured into the wood trays; therefore, it is expected that the trend, the macro-reflectance of the crushed-rock layers changes with mean particle sizes, is validated by further refined experiments. Highlights • The solar reflectance of crushed-rock layers was experimentally studied. • The macro-reflectance of crushed-rock layers is theoretically modeled. • The findings can further promote the cooling effect of crushed-rock layers. [ABSTRACT FROM AUTHOR]

Abstract Porous network ZnCo 2 O 4 nanosheets are successfully achieved by a simple hydrothermal process and adjusting the annealing temperature. The electrochemical performance of ZnCo 2 O 4 nanosheets is significantly influenced by different annealing temperatures. It has been discovered that electrode of ZnCo 2 O 4 that has be annealed at 200 °C shows an ultrahigh areal capacitance of 3.19 F cm−2 at a current density of 2 mA cm−2. An asymmetric supercapacitor device was assembled by ZnCo 2 O 4 annealed at 200 °C as positive electrode and activated carbon as negative electrode, which exhibits the energy densities of 50.7 and 37.7 Wh kg−1 at power densities of 187.6 and 2950.4 W kg−1, respectively. Highlights • Porous ZnCo 2 O 4 sheets are achieved by hydrothermal process followed by annealing. • Annealing temperature affects morphology and electrochemical properties. • Asymmetric supercapacitor device was assembled by ZnCo 2 O 4 and activated carbon. • The ZnCo 2 O 4 annealed at 200 °C shows high areal capacitance. [ABSTRACT FROM AUTHOR]