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Structure formation under non-equilibrium steady state conditions is poorly understood. A non-equilibrium steady state can be achieved in a system by maintaining a temperature gradient. A class of cross-linked microgel particles, such as poly-N-iso-propylacrylamide, is reported to increase in size due to the adsorption of water as the temperature decreases. Here, we study thermo-responsive particles with a temperature sensitive diameter in the presence of a temperature gradient, using molecular dynamics simulations with the Langevin thermostat. We find long-ranged structural order using bond order parameters in both cold and hot regions of the system beyond a certain diameter ratio of the cold and hot particles. This is due to an increase in packing and pressure in both regions. Our observations might be useful in understanding ordered structures under extreme conditions of a non-equilibrium steady state. [ABSTRACT FROM AUTHOR]

• This study investigates the differences in nutritional values and diosgenin content between lesser yams cultivated in a sub-tropical climate (Okinawa) and those cultivated in a cold region (northern Kyoto) within a plastic greenhouse. • Most of the analyzed nutritional ingredients demonstrated comparable values between plants cultivated in the sub-tropical region and within the plastic greenhouse in the cold region. The diosgenin content was 0.12 g/100 g for tubers cultivated in the sub-tropical region and 0.1 g/100 g for those cultivated in the cold region within a plastic greenhouse. • Nutritional ingredients and diosgenin contents were comparable between the two growing conditions. Dioscorea esculenta can be cultivated in sub-tropical regions and in cold regions within plastic greenhouses. The lesser yam (Dioscorea esculenta) is a phytochemical tuber that contains substantial amounts of diosgenin. Dioscorea esculenta is normally cultivated in tropical/sub-tropical regions such as African countries, and Okinawa in Japan. However, it remains unknown whether it can be successfully cultivated in cold regions within a plastic greenhouse. This study investigated the differences in nutritional values and diosgenin content between lesser yams cultivated in a sub-tropical climate (Okinawa) and those cultivated in a cold region (northern Kyoto) within a plastic greenhouse. The tubers were planted in March 2021 and harvested in January 2022. The temperature of the plastic greenhouse was 25.6 °C throughout the cultivation period. Additionally, the soil properties were potting soil with 8 % nitrogen potassium phosphate. Samples of dioscorea esculenta from both regions were used to produce 1 kg of sliced tubers from six tubers, were dried with the peel, then pulverized. The diosgenin content was analyzed for each sample, and nutritional ingredients such as moisture, carbohydrates, protein, fat, ash, sodium, and energy were measured. Most of the analyzed nutritional ingredients demonstrated comparable values between plants cultivated in the sub-tropical region and within the plastic greenhouse in the cold region. The diosgenin content was 0.12 g/100 g for tubers cultivated in the sub-tropical region and 0.1 g/100 g for those cultivated in the cold region within a plastic greenhouse. Nutritional ingredients and diosgenin contents were comparable between the two growing conditions. Dioscorea esculenta can be cultivated in sub-tropical regions and in cold regions within plastic greenhouses. [ABSTRACT FROM AUTHOR]

Freezing and thawing (F/T) is an important occurrence in cold regions influencing soil geotechnical characteristics. Current study investigates effects of lime, Rice Husk Ash (RHA) and Nano-clay on unconfined compressive strength and F/T of loess under open and closed schemes. Loess was treated with 2, 4, 6 and 8% lime and RHA and 0.5, 1.0, 1.5 and 2% Nano-clay and compacted at optimum conditions. Samples were cured for 1, 7, 14 and 28 days at 35 °C before freezing at −23 °C and thawing at room temperature for 24 h intervals. Tests conducted on untreated and RHA and Nano-clay treated samples showed total loss of strength after one F/T cycle with noticeable weight and volume changes by samples subjected to open F/T. Exposing samples to closed F/T resulted in smaller changes in volume and strength. Samples treated independently with lime or concurrently with RHA and Nano-clay showed significant resistance to F/T particularly with curing time. Formations of chemical compounds bind particles, reduce void ratio resulting in a solid durable structure resisting freezing. Open F/T proved more detrimental than closed F/T scheme exhibiting moisture accessibility to be a dominant factor on F/T process. [ABSTRACT FROM AUTHOR]

Low-temperature curing significantly affects the performance of concrete. This study explored the mechanical and microstructural characteristics of concretes modified with three kinds of nanoparticles [i.e., nano-CuO (NC), nano-SiO2 (NS), and nano-TiO2 (NT)] at curing temperatures of −6°C, −2°C, 2°C, and 6°C. The results indicated that the compressive strength of concrete cured at positive temperatures was higher than that of concrete cured at negative temperatures. Variations in the stress–strain relationships for the specimens were similar, of which the strain of concrete modified with NT was higher than those modified with NC and NS. At positive curing temperatures, the peak stress of concrete specimens modified with NC and NT first increased and then decreased as the nanomaterial content was raised, and the peak stress reached its maximum value when the nanomaterial content was 2%. However, at negative curing temperatures, the peak stress reached a maximum value when the NC content was about 3%. Besides, in terms of the compressive strength of nanoconcretes, the optimum contents of the nanomaterials to resist external loads and the optimal contents for NC, NS, and NT cured at negative temperatures were 3.0%, 1.0%, and 3%, respectively. Moreover, compared with the controlled group of ordinary portland cement without nanomaterials, for concretes with added nanomaterials, the nanomaterials can significantly fill the internal pores of the concrete, which can inhibit the development of cracks. Furthermore, low-temperature curing can inhibit hydration reactions, and the resistance to negative temperatures for concretes modified with NT was better than that for concretes modified with other nanoparticles. This study will help us better understand the influence mechanism and degree of low-temperature curing on the behavior of nanoconcrete and provide guidance for engineering construction in cold regions. [ABSTRACT FROM AUTHOR]

This study focuses on the investigation of the electromagnetic properties of multiphase inorganic materials (i.e., soils) in changing subsurface environmental conditions that are induced by climate warming. Subsurface warming in cold regions exacerbates the spatial and temporal evolution of frozen soil properties; therefore, an accurate characterization of the unfrozen water and ice content of frozen soils under different thermal conditions has become a pressing need. Several studies focused on the effect of the initial hydraulic properties on the electromagnetic properties of soils. However, detailed systematic studies on the influence of the combined effects of temperature, initial degree of saturation, applied frequency fields, and experiment scales are limited. This study aims to characterize the dielectric and electrical behavior of ice-bearing inorganic soils under the coupled effects of thermal, hydraulic, and electromagnetic conditions. A series of laboratory experiments were performed on soil samples that had different initial degrees of saturation and dry density values by electromagnetic impedance spectroscopy (EIS) and time domain reflectometry (TDR) between −10°C and 5°C. The results from the experiments revealed that the dielectric constant of the inorganic soils decreased with increasing frequency, decreasing initial volumetric water content (VWC), and temperature. The electrical resistivity values decreased with increasing frequency values, initial water content, and temperatures. In addition, the unfrozen water contents at different temperatures were calculated using a modified power law that accounts for the temperature-dependent dielectric permittivity of water and was compared with the TDR measurements. The outcomes of this study could help elucidate the intricate mechanisms of the particle–water–ice interface and their influence on the behavior of frozen soils that are needed for sustainable built and natural environments in cold regions. [ABSTRACT FROM AUTHOR]

In cold regions, the frequent occurrence of frost damage seriously affects the safety and stability of tunnel projects during construction and service time. Analyzing the formation mechanism of ice congestion in the drainage channel is of great significance for reducing the risk of frost damage. For this purpose, a mathematical model was proposed in the present work to investigate the freezing properties of water flow in the drainage channel. In this model, the latent heat of the water–ice phase change was taken into account to describe the formation process of frazil ice. Combined with the method of energy conservation, the critical distance of water freezing was derived theoretically. The field experiment and computational fluid dynamics (CFD) simulation were carried out to verify the accuracy and effectiveness of the proposed model. It showed that the estimated critical position of water freezing agreed well with the experimental and simulation results. Subsequently, the effects of hydraulic and thermodynamic factors on the freezing process of water flow were further discussed. As a practical application, the proposed mathematical model is utilized to evaluate the safety of the drainage channel of a railway tunnel in cold regions. The results demonstrate that when the flow discharge is smaller than 2,600 m3/day, there is a risk of ice congestion in the drainage channel within a range of about 960 m from the water outlet. Therefore, freeze-proof measures such as (1) thermal insulation cover plate, (2) electric heat tracing system, and (3) ground-source heat pump system should be employed in this range. [ABSTRACT FROM AUTHOR]

For evaluating the resistance performance of cement-stabilized soils in cold regions, the variation of the strength of the cemented sand–gravel (CSG) mixture concerning the hydration process should be explored. This paper aims to study the effect of freeze–thaw (F–T) cycles on the strength and microstructure of a CSG mixture with 10% cement that is subjected to 12 cycles of freezing at a temperature of −23°C for 24 h and then melted at room temperature of 24°C for the next 24 h. The uniaxial compressive strength (UCS), California bearing ratio (CBR), and weight volume loss of the samples were measured after individual F–T cycles. Furthermore, the change in the microstructure of the CSG mixture in various F–T cycles was explored. The results showed a considerable reduction in the UCS up to Cycle 3, then a slight increase for Cycles 3–6, and finally a gradual decrease for further cycles. However, the CBR and weight loss slightly fluctuated up to Cycle 6, and then gradually decreased for subsequent cycles. The majority of compounds of hydrated cement were damaged in the first three cycles. In the following cycles, between Cycles 3 and 6, the portlandite compound was dissolved and recrystallized within the microvoids. Depending on the environmental conditions, carbonation may be generated from the hydrated cement fraction, which fills the microvoids and improves the strength and structure of the mixture. During further cycles after the sixth cycle, the mechanical action of the ice lenses coupled with the disintegration of the hydrate compounds imposed many new microvoids and cracks with considerable length and width, which intensified the strength reduction of the moisture and weakened the adhesion between grains. Since cement is widely used in pavement and dam engineering for stabilizing soils, the durability of cemented soils is of prime concern. This study may help improve the durability and resistance of cemented soils in cold climates. The F–T action not only influences the macrostructure of cement-stabilized soils by imposing a wide crack and ice lens but also induces a considerable change in the complexes existing in the hydrated cement paste of the mixture. Three patterns govern the change of the mixture microstructure in various F–T cycles that correspond to the observed trend in strength. The mentioned trend for the microstructure change and, consequently, the strength variation of the CSG mixture are associated with many factors such as pH, cement content, CO2 content, moisture content within the mixture, and relative humidity within the environment. Accordingly, the pattern of microstructural changes in the CSG mixture after the middle F–T cycles may vary depending on environmental conditions. [ABSTRACT FROM AUTHOR]

Seasonal variation of soil surface temperature, such as freezing and thawing, can induce increases in the water permeability in clay by mobilizing clay pore structure. This kind of weather-induced change in clay behavior may worsen the water-sealing performance during the construction and after closure operation of engineered structures such as soil barriers for tailings or man-made slopes. There is limited knowledge towards the influence of freezing–thawing cycles on clay microstructure and saturated permeability (Ksat). This study investigated the saturated permeability of clay under freezing–thawing cycles and explored the uses of biochar as eco-friendly amendment to manipulate the permeability of compacted clay. Clay specimens were compacted with different initial water contents (30%, 34%, and 38%). The biochar application rates of 0%, 2%, 4%, 8% (by dry weight) were applied to measure their effects on the permeability of clay specimens. Saturated permeability was measured by the falling head tests. Any variation of biochar amended clay microstructure after freezing–thawing cycles was captured by the scanning electron microscope. The Ksat was reduced by about one order of magnitude when the biochar application rate was larger than 4%. This may be attributed to the increase in the filling of the biochar particles in the clay intra-aggregate pores upon the transport of liquid water during the repeated freezing–thawing processes. The biochar may thus be recommended to minimize the Ksat of geo-environmental structures in cold regions when sufficiently large application rate was used to facilitate the pore-filling process. [ABSTRACT FROM AUTHOR]

Context. Cosmic rays (CRs) heavily impact the chemistry and physics of cold and dense star-forming regions. However, the characterisation of their ionisation rate continues to pose a challenge from the observational point of view. Aims. In the past, a few analytical formulas have been proposed to infer the cosmic-ray ionisation rate, ζ2, from molecular line observations. These have been derived from the chemical kinetics of the involved species, but they have not yet been validated using synthetic data processed with a standard observative pipeline. In this work, we aim to bridge this gap. Methods. We performed a radiative transfer on a set of three-dimensional magneto-hydrodynamical simulations of prestellar cores, exploring different initial ζ2, evolutionary stages, types of radiative transfer (for instance assuming local-thermodynamic-equilibrium conditions), and telescope responses. We then computed the column densities of the involved tracers to determine ζ2, employing a recently proposed method based on the detection of H2D+. We compared this approach with a previous method, based on more common tracers. Both approaches are commonly used. Results. Our results confirm that the equation based on the detection of H2D+ accurately retrieves the actual ζ2 within a factor of two to three in the physical conditions explored in our tests. Since we have also explored a non-local thermodynamic equilibrium (non-LTE) radiative transfer, this work indirectly offers insights into the excitation temperatures of common transitions at moderate volume densities (n ≈ 105 cm−3). We also performed a few tests using a previous methodology that is independent of H2D+, which overestimates the actual ζ2 by at least two orders of magnitude. We considered a new derivation of this method, however, we found that it still leads to high over-estimations. Conclusions. The method based on H2D+ is further validated in this work and demonstrates a reliable method for estimating ζ2 in cold and dense gas. On the contrary, the former analytical equation, as already pointed out by its authors, has no global domain of application. Thus, we find that it ought to be employed with caution. [ABSTRACT FROM AUTHOR]

Polyploidization is hypothesized to improve the freezing resistance of plants in cold regions. However, adaptive strategies and key physiological mechanisms involved in the freezing resistant ability of polyploids remain unclear. In Actinidia chinensis (kiwifruits), the tetraploids and hexaploids occupy higher altitude habitats with colder climates than the diploids, providing a study system to investigate mechanisms responsible for differentiation in freezing resistance between cytotypes. We characterized environmental conditions of their natural distribution areas, and measured leaf‐level traits of cold damages and water relations at typical sites of each cytotype along an altitudinal gradient. Polyploids showed lower semi‐lethal temperature (LT50) than ice nucleation temperature (INT), reflecting a tolerance strategy to cope with freezing events in the plateau regions. More negative turgor loss points and larger cell elastic modulus of polyploids could help to alleviate damages from freezing‐induced cell dehydration, thus strengthening their tolerance to lower subzero temperatures (lower LT50). The increased supercooling capacity of polyploids (lower INT) might correlate with less extracellular ice formation due to lower osmotic potential at full turgor, apoplastic water fraction and tissue capacitance. Our study uncovers a greater cold tolerance in polyploid kiwifruits than diploids, and suggests the potential linkage between freezing tolerance and water relations. Taken together, such a divergence in stress resistance may underlie the niche shift of polyploid plants towards harsh environments. [ABSTRACT FROM AUTHOR]

Saturation flow rate (SFR) variations were analyzed using the video data collected at a signalized intersection in Winnipeg, Canada, to investigate the implications of adverse road-weather (RW) conditions for SFR distributions and characteristics. Survival analysis was implemented to develop stochastic SFR distribution functions considering censored data and a statistical analysis method was developed for determining the optimal critical vehicle (CV) for measurement of saturation headway. The analysis findings suggest that adverse RW conditions decrease SFR significantly and moves CV to the front of the queue while having little impact on SFR considering heavy vehicles. Furthermore, the findings imply that the conventional SFR estimation method overestimates the probability of saturation at a given flow rate. The proposed analysis method reveals stochastic characteristics of SFR and provides a method to estimate SFR distributions under different RW conditions, which is essential for improving the operation of signalized intersections, particularly in cold regions. [ABSTRACT FROM AUTHOR]

Thermal cracking significantly impacts the structural integrity of flexible pavements, particularly in colder regions like Canada. Limited studies investigated the impact of plastic modification of asphalt binders and mixtures using the wet method on the low-temperature performance of asphalt materials. The plastic material utilized in this project is multilayer plastic packaging (MPP). This study aims to determine whether MPP can be integrated to enhance the performance of the MPP-modified binder and MPP-modified mixtures, especially considering that MPP accounts for just over 40% of total plastic usage, making it the largest end-use market segment. This research evaluates the impact on rheological and mechanical behaviour when introducing MPP additives to conventional hot mix asphalt. This study used the wet method to test MPP-modified asphalt materials at 2%, 4%, and 8% (by weight of the asphalt binder). Test results demonstrate that the MPP modification percentage should ideally not exceed 2% as blends with 4% MPP or higher exhibited lower performance at low temperatures. The use of a softer binder as a base binder would help increase the MPP modification rates, but this hypothesis needs to be validated experimentally. [ABSTRACT FROM AUTHOR]

The phenomena of freezing damage in the cold regional tunnels have happened frequently. Therefore, in order to precisely calculate frost heaving force ( σ 1 ), based on the displacement method, a new analytical solution was proposed. The analytical solution presented in this paper was verified by the results of the model test and field measurement of σ 1 , the imperfect contact effect between frozen and unfrozen zones of surrounding rock was considered and the influence of the interaction between any two factors on frost heaving force was studied by means of orthogonal experiment and analysis of variance. The results show that: (1) the inner radius of lining ( r a ), excavation radius ( r 1 ) and freezing radius ( r f ) are highly significant for σ 1 and the interaction between the inner and outer radiuses of lining (i.e., changes of the size in inner and outer radius of lining) is also highly significant for frost heaving force ( σ 1 ); (2) the analytical solution presented in this paper can avoid the frost heaving force ( σ 1 ) with tensional property under the condition of the circular tunnel under hydrostatic pressure; and (3) sensitivity function shows that the larger Young's modulus of lining ( E I ), inner radius of lining ( r a ), freezing radius ( r f ), linear frost heaving rate ( β 0 ) and Young's modulus of frozen surrounding rock ( E II ) are, the more sensitive the factors E I , r a , r f , β 0 and E II are to σ 1 . It is expected that the results of this paper can give some novel insights for the anti-freezing design of tunnels. Highlights: Inner radius of lining is the more sensitive to frost heaving force. The interaction between the inner and outer radiuses of lining is highly significant. The ra, r1 and rf are highly significant for frost heaving force. The analytical solution can avoid frost heaving force ( σ 1 ) with tensional property. [ABSTRACT FROM AUTHOR]

A long‐standing debate exists among ecologists as to how diversity regulates infectious diseases (i.e., the nature of diversity‐disease relationships); a dilution effect refers to when increasing host diversity inhibits infectious diseases (i.e., negative diversity‐disease relationships). However, the generality, strength, and potential mechanisms underlying negative diversity‐disease relationships in natural ecosystems remain unclear. To this end, we conducted a large‐scale survey of 63 grassland sites across China to explore diversity‐disease relationships. We found widespread negative diversity‐disease relationships that were temperature‐dependent; non‐random diversity loss played a fundamental role in driving these patterns. Our study provides field evidence for the generality and temperature dependence of negative diversity‐disease relationships in grasslands, becoming stronger in colder regions, while also highlighting the role of non‐random diversity loss as a mechanism. These findings have important implications for community ecology, disease ecology, and epidemic control. [ABSTRACT FROM AUTHOR]

Freeze–thaw-cycle damage is one of the main aging problems of concrete engineering in cold regions, and the analysis of its damage mechanism has become a focus in the field of concrete aging. In this paper, on the basis of the rapid indoor freeze–thaw tests designed and carried out on concrete, computed tomography (CT) tests were carried out on concrete samples with different numbers of freeze–thaw cycles. Using CT image recognition and three-dimensional reconstruction technology, the pores, aggregates, cement matrix, and other components within the material were extracted during the freeze–thaw process. A detailed analysis for the size distribution of pores on a microscopic scale was conducted. The damage evolution law of the interfacial transition zone under the freeze–thaw action was analyzed, providing strong support for checking the validity of rapid freeze–thaw test results. [ABSTRACT FROM AUTHOR]

As an ideal candidate for the next generation of large‐scale energy storage devices, sodium‐ion batteries (SIBs) have received great attention due to their low cost. However, the practical utility of SIBs faces constraints imposed by geographical and environmental factors, particularly in high‐altitude and cold regions. In these areas, the low‐temperature (LT) performance of SIBs presents a pressing technological challenge that requires significant breakthroughs. In LT environments, the electrochemical reaction kinetics of SIBs are sluggish, the electrode/electrolyte interface is unstable, and the diffusion of sodium ions in electrode materials is slow, leading to a decrease in battery performance. Therefore, the reasonable design of electrolyte and electrode materials is of great significance for optimizing the LT performance of SIBs. In this review, the research progress of LT SIBs electrolytes, cathode, and anode materials, as well as sodium metal batteries and solid‐state electrolytes is systematically summarized in recent years, aiming to understand the design principles of LT SIBs, clarify the basic research and development of high‐performance SIBs in practical applications, and promote the development of SIBs technology in the full temperature range. [ABSTRACT FROM AUTHOR]

As construction projects in cold regions continue to increase, it has become necessary to understand the performance of concrete at low temperatures. Conducting uniaxial compressive tests on non-standard prismatic concrete specimens under low-temperature conditions and analyzing the test results allows for a comprehensive understanding of the strength variations of concrete with different strength grades at temperatures of 20 °C, 0 °C, −20 °C, −30 °C, and −40 °C. When the temperature decreases from 20 °C to 0 °C, the compressive strength of the specimens decreases, while the elastic modulus and peak strain increase. As the temperature continues to decrease, the compressive strength of the specimens increases, the elastic modulus continues to grow, and the peak strain decreases. The rising segments of the curves can be fitted using a cubic polynomial, and as the temperature decreases further, the parameters of the fitting curve gradually decrease. For concrete, being the most widely used material in the construction field, understanding its performance in low-temperature environments has become a significant research topic in the field of materials engineering and construction. [ABSTRACT FROM AUTHOR]

• Generalized Kelvin-Voigt model was able to simulate waste settlement. • Increase in stiffness with applied stress in GKV springs captured field observations. • Coupled temperature and settlement field data are essential for model validation. • Waste disposal under freezing temperatures delays waste stabilization. In Northern climates, waste placed curbside the evening before waste collection can lead to partially frozen waste at placement, which delays biodegradation and biodegradation-induced settlement. A 12-year settlement dataset collected during the filling and post-closure phases at a landfill in Québec, Canada was analyzed. The dataset showed a delay in biodegradation-induced settlement due to the first three waste lifts being placed in the winter months and exhibited an increase in the settlement rate at later times when the waste temperatures increased to values that support biodegradation. The field data also demonstrated that the stiffness of MSW increased in response to confined stress as subsequent waste lifts were added. A thermal–mechanical-biological (TMB) model was developed, in COMSOL Multiphysics, to simulate the settlement dataset. TMB integrates a Generalized Kelvin-Voigt (GKV) model, simulating instantaneous and mechanical creep settlements, with a biodegradation-induced settlement model that relates heat/gas generation with time to biodegradation-induced settlement. The thermal model simulates heat transfer through conduction and includes a biodegradation heat generation source term. The GKV stiffness parameters are expressed as a function of the applied stress to account for waste compressibility effects on mechanical response, which is consistent with field data and the research literature. The paper focuses solely on the MSW settlement field data and model predictions, with thermal response analysis presented in a separate publication. The TMB model effectively predicted waste behaviour, including resistance to compressibility under higher stress and the delay in waste settlement for waste placed in winter. The temperature and settlement data provide a valuable dataset to validate different models that can be used to predict waste settlement in cold regions. [ABSTRACT FROM AUTHOR]

This study focuses on energy conservation, reducing the amount of energy consumed to heat a room, and decreasing the intensity of carbon emissions. The research object is a room heated by a floor with a built-in finned Trombe wall (TW) located in Lanzhou, Gansu Province. ANSYS software was employed to conduct a simulation study on parameters such as fin height, transverse spacing, longitudinal spacing, arrangement mode, and fin apex angle. The simulation results were used to determine the fin parameters' thermal impact on the TW's thermal performance, including with respect to a room's thermal environment (TE). The results show that the heat transfer performance of a TW with respect to the thermal environment of a room is the greatest when the height of the heat-absorbing surface is 20 mm, the transverse spacing is 0.20 m, the longitudinal spacing is 0.533 m, and in-line 90° top-angle fins, that is, isosceles right triangle fins, are used. The average Nu number of the fin-type TW is 154.75. Compared with the average Nu number of the finless TW, which is 141.43, the average Nu number increases by 13.32 due to the addition of fins. The optimized fin-type TW has 7.77% higher convective heat supply efficiency than the finless TW. Although the PMV-PPD results of the two TW-type rooms are not very different, the comfort period of the fin-type TW room is longer. At the same time, the LPD3 of the non-finned TW and the finned TW rooms is less than 10%, the wind speed at the head and ankle is less than 0.12 m/s, the air gust sensation is not strong, and the thermal comfort is good, indicating that the addition of fins is beneficial to the improvement of indoor thermal comfort. Compared to standard rooms, finless TW rooms and fin-type TW rooms have energy-saving rates of 36.38% and 44.63%, respectively. Thus, fin-type TW rooms' energy saving rate is 8.25% higher, resulting in effective savings in heating energy consumption. Therefore, the indoor TE and auxiliary heating conditions are improved, and the integration of solar building technology can be facilitated, which offers significant reference value for energy transformation. [ABSTRACT FROM AUTHOR]

Chilling sensitivity is one of the greatest challenges affecting the marketability and profitability of sweet basil (Ocimum basilicum L.) in the US and worldwide. Currently, there are no sweet basils commercially available with significant chilling tolerance and traditional aroma profiles. This study was conducted to identify quantitative trait loci (QTLs) responsible for chilling tolerance and aroma compounds in a biparental mapping population, including the Rutgers advanced breeding line that served as a chilling tolerant parent, 'CB15', the chilling sensitive parent, 'Rutgers Obsession DMR' and 200 F2 individuals. Chilling tolerance was assessed by percent necrosis using machine learning and aroma profiling was evaluated using gas chromatography (GC) mass spectrometry (MS). Single nucleotide polymorphism (SNP) markers were generated from genomic sequences derived from double digestion restriction-site associated DNA sequencing (ddRADseq) and converted to genotype data using a reference genome alignment. A genetic linkage map was constructed and five statistically significant QTLs were identified in response to chilling temperatures with possible interactions between QTLs. The QTL on LG24 (qCH24) demonstrated the largest effect for chilling response and was significant in all three replicates. No QTLs were identified for linalool, as the population did not segregate sufficiently to detect this trait. Two significant QTLs were identified for estragole (also known as methyl chavicol) with only qEST1 on LG1 being significant in the multiple-QTL model (MQM). QEUC26 was identified as a significant QTL for eucalyptol (also known as 1,8-cineole) on LG26. These QTLs may represent key mechanisms for chilling tolerance and aroma in basil, providing critical knowledge for future investigation of these phenotypic traits and molecular breeding. [ABSTRACT FROM AUTHOR]

Climate warming and anthropogenic disturbances result in permafrost degradation in cold regions, including in the Qilian Mountains. These changes lead to extensive hillslope thermokarst (HT) formation, such as retrogressive thaw slumps, active-layer detachment slides, and thermal erosion gullies. These in turn cause, e.g., degradation of local vegetation, economic losses, infrastructure damages, and threats to human safety. However, despite its importance, there is currently no thermokarst inventory for the Qilian Mountains. Through manual visual interpretation and field validation, we therefore produce the first quantification of HT features. We count a total of 1064 HT features, with 67 % located in the upper reaches of the Heihe River basin, which encompasses ∼ 13 % of the Qilian Mountains region. We further identified that 187 HT features (18 %) existed before 2010, while the remaining 874 (82 %) were initiated in the recent period. More specifically, 392 sites (37 %) were initiated during 2010–2015 and 482 (45 %) after 2015. Thermokarst terrain is observed primarily in areas with shallow active-layer depths (average thickness 2.98 m) on northern shaded slopes of 3–25°, with low solar radiation and moderate elevations ranging from 3200 to 4000 m. This first inventory of HT features is an important and missing piece in documenting changes on the Qinghai–Tibetan Plateau, and this new dataset also provides an important basis for further studies, such as automated extraction of HT features, susceptibility analysis of HT, and estimation of losses caused by HT. The datasets are available from the National Tibetan Plateau/Third Pole Environment Data Center and can be downloaded from 10.11888/Cryos.tpdc.300805 (Peng and Yang, 2023). [ABSTRACT FROM AUTHOR]

A series of K3YSi2O7:xTm3+,yDy3+ (0 ≤ x ≤ 0.13, 0 ≤ y ≤ 0.13) white emitting phosphors were synthesized by high temperature solid state method. The crystal structure, crystal lattice occupation and luminous properties of the prepared phosphors were characterized and analyzed by XRD, Rietveld refinement, SEM and fluorescence spectra. The results show that two kinds of Y sites exist in the lattice structure, Y3+ (II) has smaller crystal field strength and better symmetry than Y3+ (I). K3YSi2O7:Dy3+ shows the characteristic emission of Dy3+ with emission peaks at 481, 573 and 665 nm. The chromaticity coordinates of K3YSi2O7:Tm3+,Dy3+ phosphors migrate from the blue region to cold white to natural white region with the increase of Dy3+ doping amount. K3YSi2O7:0.09Tm3+, 0.03Dy3+ phosphor can maintain 90% emission of the initial intensity (300 K) at 450 K. Its corresponding chromaticity coordinates (0.3367, 0.3415) are close to the standard white light (0.333, 0.333). The samples K3YSi2O7:Tm3+,Dy3+ have potential application for ultraviolet excited white-LEDs. [ABSTRACT FROM AUTHOR]

To better understand the mechanical property issues of in-service concrete-filled steel tube (CFST) bridges susceptible to natural environmental temperatures, 13 CFST stub columns were assessed under axial compression with different ambient temperatures and steel ratios, with the strength of the core concrete as the main parameters. The influence of ambient temperature on the peak strain and joint elastic modulus of the CFST stubs was investigated. The influence mechanism of steel content and core concrete strength on the residual toughness of the CFST at different ambient temperatures was revealed. In this study, we proposed a modified constitutive equation for CFST, taking into account the ambient temperature. We demonstrated that the peak strain, residual toughness ratio, and elastic modulus of the CFST stubs significantly decreased when the temperature decreased. The calculated values of the modified constitutive equation for CFST, taking into account the ambient temperature, were in good agreement with the test results and could be used to predict the trends in stress properties of the CFST stubs at different temperatures. The results could serve as a critical reference for the design and calculation of CFST structures in very cold regions. [ABSTRACT FROM AUTHOR]

The investigation on damage creep properties of rock under freeze–thaw conditions are essential for assessing the long‐term stability of rock mass engineering in cold regions. This research analyzed the damage characteristics of rock under the coupled effect of freeze–thaw cycles and loading; the damage variable under the coupled effect of freeze–thaw cycles and loading was proposed. A damage creep constitutive model was developed, and the determination method for the model parameters was proposed. The rationality of the model was calibrated using test data, and the calculation results of the proposed model were compared with classical Nishihara model. Additionally, the research analyzed the variation of model parameters with the number of freeze–thaw cycles and discussed the damage creep mechanisms of rock under the coupled effect of freeze–thaw cycles and loading. Highlights: The creep mechanism of rock under the coupled effect of freeze–thaw cycles and loading was proposed.The damage variable under the coupled effect of freeze–thaw cycles and loading was proposed.A damage creep constitutive model was established based on nonlinear rheological and damage theory.The variation of model parameters with the number of freeze–thaw cycles were analyzed. [ABSTRACT FROM AUTHOR]

To effectively reduce building energy consumption and enhance indoor thermal comfort, this study developed a sensitivity analysis and multi-objective optimization method for an office building in Hangzhou considering the effects of parameter interactions. We utilized Latin hypercube sampling (LHS) to sample the parameters and subsequently simulated the energy consumption and discomfort hours for the building's four orientations. Following this, Gaussian process regression models were established, and the feature importance ranking method (FIRM) alongside an interaction effects method were employed to quantify the sensitivity of 10 parameters. Lastly, a multi-objective optimization was performed for total energy consumption and discomfort hours, yielding a set of Pareto-optimal solutions. Through the VIKOR method, the optimal solution within the Pareto set was identified, resulting in three sets of optimal solutions. [ABSTRACT FROM AUTHOR]

As the impact of climate change intensifies, meeting the energy demand of buildings in China's cold regions is becoming increasingly challenging, particularly in terms of cooling energy consumption. The effectiveness of integrating phase change material (PCM) into building envelopes for energy saving in China's cold regions is unclear. The aim of this study is to assess the effectiveness of PCM integration in building enclosures for energy efficiency in these regions. The research monitored and recorded indoor temperature data from typical residential cases from May to September. This measured data was then used to validate the accuracy of EnergyPlus22-1 software simulation models. Subsequently, the calibrated model was utilized to conduct a comparative analysis on the effects of PCM on indoor temperatures and cooling energy consumption across these regions. The results of these comparative analyses indicated that PCM can alleviate indoor overheating to varying degrees in severe cold regions of China. Focusing on north-facing bedrooms, applying PCMs reduced the duration of overheating in non-air-conditioned buildings in severe cold regions of China by 136 h (Yichun), 340 h (Harbin), 356 h (Shenyang), and 153 h (Dalian). In terms of cooling energy consumption, the energy saved by applying PCMs ranged from 1.48 to 13.83 kWh/m2. These results emphasize that the performance of PCM varies with climate change, with the most significant energy-saving effects observed in severe cold regions. In north-facing bedrooms in Harbin, the energy-saving rate was as high as 60.30%. Based on these results, the study offers guidance and recommendations for feasible passive energy-saving strategies for buildings in severe cold and cold regions of China in the face of climate change. Additionally, it provides practical guidance for applying PCMs in different climatic zones in China. [ABSTRACT FROM AUTHOR]

The rice production system in China is facing challenges, including declining soil fertility and a stagnant rice yield. This study aimed to test whether integrating the return of straw to fields with less power puddling could simultaneously enhance soil fertility and rice yields. Therefore, field experiments were conducted in Heilongjiang Province, a key rice-growing region in China, from 2017 to 2021, using three different planting methods: control group (CK), straw return (SR) and straw return integrated with less power puddling (SR + LP). The results showed that small soil aggregates (particle diameter < 0.25 mm) and soil bulk density were significantly decreased when straw return was integrated with less power puddling. These changes contributed to the preservation of soil structure. Simultaneously, this approach significantly increased soil ammonium nitrogen content from 9.9 to 10.9 mg kg−1, organic matter content from 35.0 to 36.2 g kg−1, available nitrogen content from 140.5 to 147.0 mg kg−1 and available potassium content from 128.6 to 136.8 mg kg−1 at mature stage on average. Consequently, the post-heading stored assimilates accumulation of rice was increased from 6.12 to 6.43 t ha−1, and the nitrogen, phosphorus and potassium accumulation of rice were increased by 7.85 kg ha−1, 1.13 kg ha−1 and 5.68 kg ha−1, respectively. These changes ultimately resulted in a higher 1000 g weight and filled grain rate, providing the foundation for higher yields (an increase from 9.31 t ha−1 to 9.55 t ha−1). Furthermore, this approach also increased the net income for farmers by USD 14 t ha−1. In summary, this study demonstrates that integrating straw return with less power puddling can enhance soil's nutrient supply and retention capacity. This enhancement may boost the absorption and transportation of nutrients, ultimately establishing the groundwork for higher yields and economic benefits by enhancing the 1000 g weight and filled grain rate. Future research should delve deeper into its applicability across different ecosystems and investigate the yield-increasing mechanisms. [ABSTRACT FROM AUTHOR]

Background: Low-temperature stress significantly restricts maize germination, seedling growth and development, and yield formation. However, traditional methods of evaluating maize seedling quality are inefficient. This study established a method of grading maize seedling quality based on phenotypic extraction and deep learning. Methods: A pot experiment was conducted using different low-temperature combinations and treatment durations at six different stages between the sowing and seedling phases. Changes in 27 seedling quality indices, including plant morphology and photosynthetic performance, were investigated 35 d after sowing and seedling quality grades were classified based on maize yield at maturity. The 27 quality indices were extracted, and a total of 3623 sample datasets were obtained and grouped into training and test sets in a 3:1 ratio. A convolutional neural network-based grading method was constructed using a deep learning model. Results: The model achieved an average precision of 98.575%, with a recall and F1-Score of 98.7% and 98.625%, respectively. Compared with the traditional partial least squares and back propagation neural network, the model improved recognition accuracy by 8.1% and 4.19%, respectively. Conclusions: This study provided an accurate grading of maize seedling quality as a reference basis for the standardized production management of maize in cold regions. [ABSTRACT FROM AUTHOR]

Terrestrial ecosystem resilience is crucial for maintaining the structural and functional stability of ecosystems following disturbances. However, changes in resilience over the past few decades and the risk of future resilience loss under ongoing climate change are unclear. Here, we identified resilience trends using two remotely sensed vegetation indices, analyzed the relative importance of potential driving factors to resilience changes, and finally assessed the risk of future resilience loss based on the output data of eight models from CMIP6. The results revealed that more than 60% of the ecosystems experienced a conversion from an increased trend to a declined trend in resilience. Attribution analysis showed that the most important driving factors of declined resilience varied regionally. The declined trends in resilience were associated with increased precipitation variability in the tropics, decreased vegetation cover in arid region, increased temperature variability in temperate regions, and increased average temperature in cold regions. CMIP6 reveals that terrestrial ecosystems under SPP585 are expected to experience more intense declines in resilience than those under SSP126 and SSP245, particularly in cold regions. These results highlight the risk of continued degradation of ecosystem resilience in the future and the urgency of climate mitigation actions. [ABSTRACT FROM AUTHOR]

Frost heave susceptibility is a key index for designing the subgrade fillings of high-speed railways in cold regions. The existing methods for assessing frost heave susceptibility are mainly empirical or semi-empirical, and most of them are defined based on the fine content of soils. This study attempts to propose a new criterion based on the analytical solution of frost heave in the soil. A number of experiments are used to validate the proposed analytical model, which shows that the computed value of frost heave matches well with the measured data. The proposed model indicates that frost heave is a proportional function of the square root of time. Thus, the slope R named frost heave classification index of the proportional function is defined as a new index for frost heave susceptibility classification. A value of R less than 0.21 corresponds to a non-frost heave susceptibility condition, a value greater than 1.18 corresponds to a high frost heave susceptibility condition, and a value in the range of 0.21 and 1.18 means a frost heave susceptibility condition. R is directly related to the boundary temperatures and soil–water and soil-freezing characteristics. The parameter study shows that reducing the values of SWCC fitting parameter α and cold end temperature Tc or increasing the values of permeability of frozen soil kf, the saturated volumetric water content θs, the unfrozen water content at the frost front θu and the residual volumetric water content θr increases the possibility of frost heave. Compared with the existing method, the new index has a clear theoretical basis, and the parameters are easily obtained. It may be a rational method for assessing frost heave susceptibility. [ABSTRACT FROM AUTHOR]

An understanding of the rheological characteristics of surrounding rock is key to predicting the large deformations of tunnels in soft rock in cold regions, particularly due to freeze–thaw (F–T) damage of the surrounding rock. Therefore, in this study, a series of F–T cycle and triaxial creep tests of surrounding rocks were conducted on the basis of typical tunnel projects in cold regions, and the parameters of the test data were identified by the fractional-order creep damage constitutive equation. Then, a constitutive model was embedded into the Fast Lagrangian Analysis of Continua in 3 Dimensions software to analyze the coupled creep deformations of the surrounding rock and supporting structure in response to F–T cycles while excavating the Ningchan tunnel. The calculated results accurately reflected the creep deformation characteristics of the surrounding monitoring points after tunnel excavation under different numbers of F–T cycles. Finally, a tunnel operation model was derived and used to analyze the creep deformation characteristics of a tunnel during operation in a cold area. The calculation results showed that with increasing time, the lining structure and surrounding rock at different monitoring points in the tunnel underwent various degrees of creep deformation. Additionally, the creep deterioration effect of the surrounding rock was more severe after the F–T cycles, which endangered traffic safety. [ABSTRACT FROM AUTHOR]

Degrading rock wall permafrost was found responsible for the increase in rockfall and landslide activity in several cold mountain regions across the globe. In Greenland, rock wall permafrost has so far received little attention from the scientific community, despite mountains being a predominant feature on the ice-free coastline and landslide activity being significant. In this study, we aim to make a first step towards a better understanding of rock wall permafrost in Greenland by modelling rock wall temperatures in the mountain area around the town of Sisimiut, which is 68° N on the west coast of Greenland. We first acquire rock surface temperature (RST) data for the period September 2020–September 2022 to model rock surface temperatures from weather forcing. The model is then applied to weather data from 1870 to 2022, generating rock surface temperatures to force transient heat transfer simulations over the same period. By extrapolating this method at the landscape scale, we obtain permafrost distribution maps and ad hoc simulations for complex topographies. Our model results are compared to temperature data from two lowland boreholes (100 m depth) and geophysical data describing frozen and unfrozen conditions across a mid-elevation mountain ridge. Finally, we use regional carbon pathway scenarios 2.6 and 8.5 to evaluate future evolution of rock wall temperatures until the end of the 21st century. Our data and simulation describe discontinuous permafrost distribution in rock walls up to roughly 400 m a.s.l. Future scenarios suggest a decline of deep frozen bodies up to 800 m a.s.l., i.e. the highest summits in the area. In summary, this study depicts a picture of warm permafrost in this area, highlighting its sensitivity to ongoing climate change. [ABSTRACT FROM AUTHOR]

An extended ordinary state-based peridynamic model was developed to investigate the crack propagation of surrounding rock due to tunnel excavation. The frost heave effect on the crack surface was described by an equivalent pressure density. Two numerical examples were conducted to verify the effectiveness and robustness of the proposed model. Moreover, the influence of frost heave pressure, buried depth and rock elastic modulus on damage characteristics of the surrounding rock was investigated. The results demonstrate that massive microcrack damage will be formed at the invert when the tunnel is excavated in a deeply buried rock mass or soft rock stratum. A peridynamic model of rock mass under excavation and frost heave was constructed. Damage characteristics of surrounding rock could be simulated efficiently. Frost heave load was exerted on the crack surface by an equivalent pressure density. The effects of frost heave load, buried depth and rock elastic modulus were studied. [ABSTRACT FROM AUTHOR]

Cold stimulation is the most common stressor in cold regions. Continuous cold stimulation can cause a series of pathophysiological changes in the body, such as aggregated neutrophils, macrophage activation, and increased inflammatory factors, which is also a risk factor for erectile function impairment. In addition, necroptosis is an important form of programmed cell death. However, the mechanisms of necroptosis in erectile function impairment due to cold stimulation have been very poorly studied. Therefore, we explored the mechanism of tumor necrosis factor-α (TNF-α)-mediated receptor interacting protein kinase 1 (RIP1)/receptor interacting protein kinase 3 (RIP3) necroptosis pathway on erectile function among cold-stressed rats. First, we established a cold-stressed rat model using cold stimulation and selected those rats that had developed erectile function impairment. Then, we used Necrostatin-1 (RIP1 specific inhibitor, Nec-1), Etanercept (TNF-α inhibitor, Ent), and Sildenafil (Sil) to intervene for 14 days and subsequently assessed their erectile function by apomorphine test and sexual behavioural test. Lastly, we performed various molecular studies and histopathological analyses of penile tissues collected from these rats after the experiments. We found that erectile function was impaired in cold-stressed rats, with increased penile tissue fibrosis and elevated levels of TNF-α and necroptosis. Contrastingly, intervention with Nec-1 and Ent restored erectile function, reduced penile tissue fibrosis, and decreased TNF-α and necroptosis levels, consistent with the results of intervention with Sil. Based on these results, we confirmed that the TNF-α-mediated RIP1/RIP3 necroptosis pathway was significantly altered in cold-stressed rats. In conclusion, inhibition of the TNF-α-mediated RIP1/RIP3 necroptosis pathway improved erectile function, suggesting that the specific downstream mechanisms need to be further explored. [ABSTRACT FROM AUTHOR]

The distribution of brGDGT lipids produced by soil bacteria has been used to reconstruct temperatures in marine and terrestrial settings as far back as the Cretaceous period. However, modern calibrations of this proxy have primarily relied on air rather than in situ soil temperatures, which can differ by more than 10 °C. Furthermore, the influence of other parameters such as temperature seasonality and soil chemistry on brGDGT lipids is not fully understood. We measured brGDGT distributions, in situ soil temperatures, pH, soil water content, and electrical conductivity on soils from the Eastern Canadian Arctic and Iceland. We compiled our results with those of published soil brGDGT studies that also provide in situ soil temperatures and ancilliary measurements and generated global temperature and pH calibrations from the resulting dataset. Soil temperatures outperformed air temperatures in these calibrations, with mean summer soil temperature providing the highest-performing fit among the 10 tested soil temperature parameters. When applied to a loess/paleosol sequence from the Chinese Loess Plateau, these new calibrations produced paleotemperature and paleo-pH histories consistent with the results of previous studies, encouraging the application of our new calibrations on a broader scale. We also detected 7-methyl and IIIa" brGDGT isomers in our Eastern Canadian Arctic and Iceland soils, which have been shown in lakes to relate to salinity and anoxia, respectively. While neither correlated with bulk soil properties such as conductivity, soil water content, or pH, these brGDGT isomers did correlate with seasonality and winter soil temperature. We hypothesize that these compounds are generated in winter by bacteria in habitable niches of more saline, sometimes anoxic liquid water in the otherwise frozen soil matrix. Finally, we report the presence of overly branched GDGTs with m / z = 1064 and suggest that these heptamethylated tetraethers should be investigated as a potential tool for improving brGDGT calibrations. Overall, our results expand our understanding of the seasonality of brGDGT production, especially at high latitudes, and provide in situ soil temperature and pH calibrations for global use. [ABSTRACT FROM AUTHOR]

Despite the long-term implementation of air pollution control policies in northeast China, severe haze pollution continues to occur frequently. With the adoption of a megacity (Changchun) in northeast China, we analysed the vertical characteristics of aerosols and the causes of aerosol pollution throughout the year using multisource data for providing recommendations for controlling pollution events (i.e., straw burning and fireworks). Based on a ground-based LiDAR, it was found that the extinction coefficient (EC) of aerosols at a height of 300 m in Changchun was highest in winter (0.44 km−1), followed by summer (0.28 km−1), with significant differences from those in warmer regions, such as the Yangtze River Delta. Therefore, it is recommended that air pollution control policies be differentiated between winter and summer. On Chinese New Year's Eve in Changchun, the ignition of firecrackers during the day and night caused increases in the EC at a height of 500 m to 0.37 and 0.88 km−1, respectively. It is suggested that the regulation of firecracker ignition should be reduced during the day and strengthened at night. Based on the CALIPSO and backward trajectory analysis results, two events of dust–biomass-burning composite pollution were observed in March and April. In March, the primary aerosol component was dust from western Changchun, whereas in April, the main aerosol component was biomass-burning aerosols originating from northern and eastern Changchun. Hence, reducing the intensity of spring biomass burning can mitigate the occurrence of dust–biomass-burning composite pollution. These findings can provide emission policy suggestions for areas facing similar issues regarding biomass-burning transmission pollution and firework emissions. [ABSTRACT FROM AUTHOR]

The performance of lithium-ion batteries may decline at cold temperatures, leading to reduced capacity and electrolyte freezing. To ensure proper operation of energy storage stations in cold regions, heating methods must be designed to maintain batteries at 283.15 K while limiting the temperature difference to less than 5 K. Theoretical analysis and simulation of a battery heating method were conducted using a 22 Ah lithium iron phosphate battery as the research object at 253.15 K. A heating method was designed using Positive Temperature Coefficient (PTC) aluminum plate heaters. Results showed that under the condition of an ambient temperature of 253.15 K and a discharge rate of 1 C, five 120 W PTCs could increase the peak temperature to 283.46 K at 1000 s. The heating method was further optimized by changing the PTC number (2, 3, and 4) and size (corresponding to 120%, 100%, 80%, and 60% of the lithium-ion battery dimensions), and it was found that by using 3 PTC heating plates with 80% size, the maximum temperature could be increased to 289.85 K and the average temperature difference was 4.82 K at 1000 s, meeting the needs of battery operation. The heating method was shown to be effective in rapidly increasing the battery temperature at lower ambient temperatures (243.15, 253.15, and 263.15 K), increasing the rate of temperature increase by 32.4% at 243.15 vs 253.15 K and 45.2% at 263.15 K. [ABSTRACT FROM AUTHOR]

In cold regions, the flow of outside air into a tunnel often causes freeze–thaw damage to the surrounding rock, and insulation methods are usually adopted to avoid this damage. In this study, the heat transfer in a multilayer tunnel structure that includes a rock layer, an initial lining, an insulation layer, and a secondary lining was investigated, and convection between the tunnel air and the inner surface of the tunnel lining was considered. A mathematical model describing the heat transfer process was established, and an analytical solution for the temperature field was developed using Duhamel's principle and the separation-of-variables method. The model and the solution were verified by comparing the computational results of the analytical solution with the computational results and in situ measurements available in the literature. By treating the minimum temperature of the inner surface of the surrounding rock as a function of the insulation thickness, a procedure to determine the minimum insulation thickness that ensures no freeze–thaw damage to the surrounding rock was developed based on the analytical solution using the bisection method. Computational examples were presented, and the effects of different factors on the minimum temperature of the inner surface of the surrounding rock and minimum insulation thickness were investigated. [ABSTRACT FROM AUTHOR]

• A 2 kW-class FPSHP prototype was designed, built and tested. • The analysis of the distribution of acoustic field and exergy loss were carried out. • The influence of key parameters was studied by simulation and experiment. • The prototype can provide 2253 W of heating with a COP h of 2.76. Compared with conventional vapour-compression heat pump technology, the free-piston Stirling heat pump technology attracts wide attention for its high efficiency, reliability, and environmental friendliness. In this work, a free-piston Stirling heat pump prototype with a two-kilowatt capacity, which can operate with an outside ambient temperature ranging from -20 to 10 °C, was designed, built and tested. First, numerical simulations were carried out to explore the distributions of the acoustic field and exergy loss. Second, the effects of several operating parameters on the heating performance were numerically investigated in detail. Finally, to validate the accuracy of the simulation results, verification experiments were conducted on the experimental platform of a free-piston Stirling heat pump driven by a dual-opposed linear compressor. Experimental data show that with a hot-end temperature of 45 °C and outside ambient temperature of 0 °C, the prototype achieved a heating capacity of 2253 W with a corresponding COP h of 2.76 (based on PV power input) and a relative Carnot efficiency of 39.1 %; in particular, the prototype was able to achieve a COP h of 2.5 when pumping heat from -20 °C to 45 °C for 3.25 MPa mean pressure. The simulation and experimental results demonstrated that the free-piston Stirling heat pump system has good potential to achieve high efficiency as a heating supply in a cold region. [ABSTRACT FROM AUTHOR]

Natural pumice concrete (NPC) is a building material with the advantages of light weight and high thermal resistance. In cold regions, NPC undergoes damage from freeze–thaw cycles. Freeze–thaw damage is closely related to changes in the pore structure of concrete. Therefore, it is meaningful to investigate the evolution characteristics and damage threshold of pore structure for NPC under freeze–thaw cycles. In this study, freeze–thaw cycle tests and nuclear magnetic resonance (NMR) tests were designed. The characteristics of the evolution of the pore structure during freeze–thaw cycles were discussed. The results showed that the porosity in NPC specimens increases with the number of freeze–thaw cycles and the main evolution of the pores showed the degradation of fine capillary pores (10 nm < r < 100 nm) into coarse capillary pores (100 nm < r < 1000 nm) and non-capillary pores (r > 1000 nm). After freeze–thaw cycles, the proportion of coarse capillary pores and non-capillary pores increased by 4.83–10.59%. This evolutionary feature directly leads to the degradation of the mechanical properties of NPC. Additionally, a pore damage model was established, and the pore damage threshold was also calculated based on the experimental results. The obtained damage threshold of pore structure can provide the theoretical foundation for the application of NPC in cold regions. [ABSTRACT FROM AUTHOR]

Understanding the mechanism of disasters and designing protection systems for cold region tunnels require a fundamental analysis of the constitutive model of rock under freeze–thaw (FT) cycles and loading. In this paper, a novel freeze–thaw damage model that can describe the damage evolution of rock materials subjected to different freeze–thaw cycles is proposed. The advantage is that it is in good agreement with the experimental damage evolution with different damage variables. Combining with the FT damage model, a coupled FT and loading constitutive damage model is developed. We perform freeze–thaw cycle tests on Sichuan sandstone to validate the coupled model. The coupled model is also compared with the experimental data of granite under triaxial compression to further check the performance of the proposed model. Our findings suggest that the model is able to consider the void compaction and the influence of confining pressure. The model effectively captures the nonlinear mechanical behavior of rocks under different freeze–thaw cycles. We establish a coupling effect by analyzing the correlation between model parameters, deformation, and failure mechanism of the developed model. Highlights: A novel freeze–thaw damage model is proposed, which accurately describes the damage evolution of rock materials under different freeze–thaw cycles. A coupled freeze–thaw and loading constitutive damage model of rock is developed, which takes into account the void compaction and the influence of confining pressure. The model effectively captures the nonlinear mechanical behavior of rocks under different freeze–thaw cycles and provides insights into the deformation and failure mechanisms of rocks. [ABSTRACT FROM AUTHOR]

Groundwater is a valuable resource in northern Canada, which is used as a primary drinking water source for many residents and ensures the health of ecosystems. However, no groundwater vulnerability assessment methods have been specifically developed for these cold regions. The extreme seasonal climate and frozen ground conditions present unique challenges in assessing groundwater and well vulnerability. Climate warming and permafrost thaw, population density, contaminant threats, and Indigenous knowledge are key features to integrate within adapted assessment approaches. [ABSTRACT FROM AUTHOR]

Global warming firstly influences the permafrost regions where numerous and rich world hydrocarbon deposits are located. Permafrost thawing has caused severe problems in exploring known hydrocarbon deposits and searching for new targets. This process is also dangerous for any industrial and living regions in cold regions. Knowledge of permafrost's ice and unfrozen water content is critical for predicting permafrost behavior during the water–ice transition. This is especially relevant when ice and permafrost are melting in many regions under the influence of global warming. It is well known that only part of the formation's pore water turns into ice at 0 °C. After further lowering the temperature, the water phase transition continues, but at gradually decreasing rates. Thus, the porous space is filled with ice and unfrozen water. Laboratory data show that frozen formations' mechanical, thermal, and rheological properties strongly depend on the moisture content. Hence, porosity and temperature are essential parameters of permafrost. In this paper, it is shown that by combining research in three fields, (1) geophysical exploration, (2) numerical modeling, and (3) temperature logging, it is possible to estimate the porosity of permafrost in situ. Five examples of numerical modeling (where all input parameters are specified) are given to demonstrate the procedure. This investigation is the first attempt to quantitatively analyze permafrost's porosity in situ. [ABSTRACT FROM AUTHOR]

Ice chemistry in the dense, cold interstellar medium (ISM) is probably responsible for the formation of interstellar complex organic molecules (COMs). Recent laboratory experiments performed at T ∼ 4 K have shown that irradiation of CO:N2 ice samples analog to the CO-rich interstellar ice layer can contribute to the formation of COMs when H2 molecules are present. We have tested this organic chemistry under a broader range of conditions relevant to the interior of dense clouds by irradiating CO:15N2:H2 ice samples with 2 keV electrons in the 4–15 K temperature range. The H2 ice abundance depended on both, the ice formation temperature and the thermal evolution of the samples. Formation of H-bearing organics such as formaldehyde (H2CO), ketene (C2H2O), and isocyanic acid (H15NCO) was observed upon irradiation of ice samples formed at temperatures up to 10 K, and also in ices formed at 6 K and subsequently warmed up and irradiated at temperatures up to 15 K. These results suggest that a fraction of the H2 molecules in dense cloud interiors might be entrapped in the CO-rich layer of interstellar ice mantles, and that energetic processing of this layer could entail an additional contribution to the formation of COMs in the coldest regions of the ISM. [ABSTRACT FROM AUTHOR]

The freezing damage of rock tunnels in cold region involves ice-water phase change and complicated interaction of Thermo–Hydro–Mechanical (THM) field. Taking the fractured rock mass of cold region tunnels as research subject, the THM coupling model of cold region tunnels was established, which is based on the seepage mechanics, heat transfer theory, damage mechanics and equivalent continuum theory. This model could reflect the anisotropic properties of deformation, water migration and heat transfer caused by the initial fracture of rock mass. The construction and operation processes of a rock tunnel in cold region were simulated, and results were compared with the measured value and predecessor's achievements. It shows that proposed model could reflect the anisotropic property of surrounding rock and the simulated deformation and stress are not symmetrical. Compared with the literature, the calculated results in this paper are closer to the measured values. The insulating layer has a significant effect on the stress of the supporting structures. The maximum tension stress of the lining is 4.5 times as that without insulating layer, and the lining will be destroyed for the overlarge tension stress. [ABSTRACT FROM AUTHOR]

Micronutrients play a crucial role in enabling crops and vegetables to achieve optimum productivity, improve storage quality, and overcome physiological disorders. The present study focuses on evaluating the effects of the foliar application of Zinc, Borax, and their combined application in enhancing onion yield and shelf life of Allium cepa L. (cultivars Red coral and Liberty). An experimental study was conducted for two years at Agriculture Research Unit, DIHAR Leh (34.1383˚N, 77.5725˚E) to assess the impact of different doses of ZnSO4, Borax, and their combination on onion yield and shelf-life improvement. Four treatments of ZnSO4 and Borax (T1: 0.5% ZnSO4; T2: 0.25% Borax; T3: 0.5% ZnSO4 + 0.25% Borax and T4: control) were applied twice, once at 30 DAT and again after 45 DAT. Among four treatments, T3 showed a significant impact on growth parameters, yield, and onion shelf-life followed by T1 and T2 compared to the control T4 treatment. Foliar sprays of ZnSO4 and Borax, rather than only ZnSO4 or Borax application, significantly improved plant height, leaves number, leaf area index, chlorophyll content, and onion yield. The storage examination revealed an important correlation between the concurrent application of ZnSO4 and Borax on onion, demonstrating a significant reduction in weight loss, an increase in Total Soluble Solids (T.S.S), and an extension of the onions' shelf life. These findings hold the potential for significant implications in elucidating the optimal utilization of micronutrients for improving onion cultivation and preservation practices in cold desert regions of Ladakh. [ABSTRACT FROM AUTHOR]

Concrete constructed using recycled aggregates in place of natural aggregates is an efficient approach to increase the construction sector's sustainability. To improve recycled aggregate concrete (RAC) technologies in permafrost, it is essential to certify the stability in frost‐induced conditions. The main goal of this study was to use support vector regression (SVR) methods to forecast the frost durability (DF) of RAC on the basis of durability agent value in cold climates. Herein, three optimization methods called Ant lion optimization (ALO), Grey wolf optimization (GWO), and Henry Gas Solubility Optimization (HGSO) were employed for indicating optimal values of SVR key parameters. The results depicted that all developed models have capability in predicting the DF of RAC in cold regions. The values of OBJ as a comprehensive index depicted that the GWO−SVR model has the higher value at 0.0571 as the weakest model, then ALO−SVR at 0.0312 recognized as the second‐highest model, and finally the HGSO−SVR system at 0.0224 mentioned as outperformed model. ALO−SVR and GWO−SVR approaches were likewise capable of accurately forecasting the DF of RAC in cold regions, but the created HGSO−SVR method outperformed them all when taking into account the explanations and justifications. [ABSTRACT FROM AUTHOR]

The process of icing and the resulting layered ice masses, called aufeis, are caused by the freezing of overflow originating from groundwater or surface water. Aufeis can directly impact infrastructure and property, most commonly through winter ice formation and spring flooding within, against, and on the surface of hydraulic structures and transportation infrastructure. They also represent a safety concern for drivers. This geohazard often needs to be managed proactively and efficiently to mitigate associated risks. This paper provides an overview of the consequences of aufeis in northwestern Canada. A total of 50 existing and novel icing and aufeis mitigation approaches are described and classified. The context of applicability for each approach is identified, considering the source of water, the type of infrastructure, and its role in the formation of aufeis. Finally, future research avenues to support the development or improvement of aufeis risk reduction techniques are presented. [ABSTRACT FROM AUTHOR]

The process of icing involves the freezing of overflow layers, on ground or within streams, and results in ice bodies called "aufeis" that are common in most northern landscapes. Knowledge about aufeis is still limited despite the cold region engineering challenge they represent. Understanding the causes of overflow events leading to aufeis development represents a key for the prediction, mitigation, and management of this geohazard and can also support the planning and design of infrastructure in the North. This paper introduces a practical classification for the diverse range of overflow processes that generate aufeis, including under-represented processes, such as the instability of winter streamflow. Importantly, it distinguishes flow conveyance from water supply overflow processes and describes the temporal aspect of icing intensity. Finally, research topics are proposed to improve our understanding of aufeis, including their predictability, the impact of climate change on their occurrence and extent, and stream morphology–aufeis interaction. [ABSTRACT FROM AUTHOR]

After the repeated freezing and dissolution of fractured rock masses in cold regions, the liquid present in the pores undergoes a water–ice phase transition, resulting in frost heave forces and damage to the internal structure of the rock mass. This causes the rock masses to continuously develop new cracks, which further expand and connect, leading to rock mass failure and ultimately reducing the overall stability of the rock mass in engineering projects. In this study, uniaxial compression tests, direct shear tests, and Brazilian splitting tests were conducted on rock after freeze–thaw cycles (FTCs), and the changes in the physical and mechanical properties of the rock under freeze–thaw conditions were obtained (this study used raw rock from an engineering project and processed it into symmetrical jointed rock samples). The roughness of the shear fracture surfaces was analyzed through 3D cross-sectional scanning experiments. Using statistical damage theory, the mechanism of freeze–thaw damage was analyzed, and a constitutive model for freeze–thaw rock damage was established. The research results can provide a theoretical basis and support for engineering safety and stability in cold regions. [ABSTRACT FROM AUTHOR]