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Seasonally frozen ground regulates groundwater–surface water interactions in saline lake basins, altering water balance, salinity gradients, and biogeochemical processes. Using density‐dependent reactive transport simulations in the Badain Jaran Desert, China, we evaluate how freeze–thaw cycles affect groundwater flow, salt dynamics, and nutrient fluxes under varying salinity conditions. Our results show that seasonal freezing suppresses evaporation and enhances down‐gradient groundwater flow, shifting the fresh–saline interface lakeward and limiting inland saltwater intrusion. During the cold season, both fresh and recirculated groundwater to lakes increase, offsetting evaporative losses and enhancing lake water storage. Simultaneously, nutrient fluxes to lakes intensify, reflecting enhanced mobilization from groundwater reservoirs. These findings emphasize the hydrogeological and biogeochemical significance of seasonal freezing in saline basins.

The effect of low voltage electrostatic field (LVEF, 2500 V, 0.2 mA) on oxidative denaturation of myofibrillar proteins (MPs) in repeatedly freeze–thaw (F-T, both 24 h) lamb was investigated in this study. F-T cycles intensified MP oxidative denaturation and structural destruction, with the influences becoming more severe after 1, 3, and 5 F-T cycles. The samples of the LVEF-assisted F-T cycles (LFT) exhibited lower carbonyl/dityrosine content, “r” value, and surface hydrophobicity, higher sulfhydryl content, solubility, Ca 2+ -ATPase activity, α -helix content, and fluorescence intensity under the identical F-T cycles ( P  < 0.05) in comparison with the common F-T cycles (CFT). Although the suppression of LVEF on protein oxidation decreased with the boost in the amount of F-T cycles, the effectiveness was still remarkable compared to samples without LVEF treatment. These original study findings would assist supply theoretical proof for the usage of LVEF in the freezing, storing, and transporting of frozen meat.

The mechanics of rock masses in cold regions have attracted the attention of researchers from all over the world, and the concern here is that the mechanical properties of rock masses are inevitably weakened under freeze–thaw cycles. In this paper, first, granite samples were subjected to different freeze–thaw cycles, and then treated in four different states, such as saturated and frozen states, saturated and normal temperature states, dry and frozen states, as well as dry and normal temperature states. The impact compression test was carried out using the Split Hopkinson Pressure Bar (SHPB) device. Results show that the impact strength of granite samples deteriorates with the increase of freeze–thaw cycles in the same state; for samples in different states, although the number of freeze–thaw cycles is equal, the degree of deterioration of the impact strength is different. For freeze–thawed granite samples in the same state, the dynamic elastic modulus decreases with the increase of freeze–thaw cycles, and its degree of decrease is different for different states. Under the same freeze–thaw cycles, the deterioration of mechanical properties of granite samples is different in four different weather states; for example, the dynamic elastic modulus from large to small is generally as follows: saturated and frozen states, saturated and normal temperature states, dry and frozen states, as well as dry and normal temperature states. Finally, the freeze–thaw influence factor is proposed to describe the damage of granite samples. All in all, it can be concluded that water and low temperature strengthen the influence of freeze–thaw cycles on the dynamic mechanical properties of granite.

Changes in the freeze–thaw cycles of shallow soil have important consequences for surface and subsurface hydrology, land–atmosphere energy and moisture interaction, carbon exchange, and ecosystem diversity and productivity. This work examines the shallow soil freeze–thaw cycle on the Tibetan Plateau (TP) using in–situ soil temperature observations in 0–20 cm soil layer during July 1982–June 2017. The domain and layer averaged beginning frozen day is November 18 and delays by 2.2 days per decade; the ending frozen day is March 9 and advances by 3.2 days per decade; the number of frozen days is 109 and shortens by 5.2 days per decade. Altitude and latitude combined could explain the spatial patterns of annual mean freeze–thaw status well. Stations located near 0 °C contour line experienced dramatic changes in freeze–thaw cycles as seen from subtropical mountain coniferous forest in the southern TP. Soil completely freezes from surface to 20-cm depth in 15 days while completely thaws in 10 days on average. Near-surface soil displays more pronounced changes than deeper soil. Surface air temperature strongly influences the shallow soil freeze–thaw status but snow exerts limited effects. Different thresholds in freeze–thaw status definition lead to differences in the shallow soil freeze–thaw status and multiple-consecutive-day approach appears to be more robust and reliable. Gridded soil temperature products could resolve the spatial pattern of the observed shallow soil freeze–thaw status to some extent but further improvement is needed.

The stability of rock masses in regions is significantly affected by freeze–thaw and load, so it is necessary to study the mechanical characteristics of rock under freeze–thaw conditions. To investigate the strength degradation characteristics of water-saturated red sandstone, the mechanical properties and damage mechanisms were analyzed under freeze–thaw and triaxial load conditions. The results shows: The damage caused by freeze–thaw cycles is mainly concentrated on the side and edge area of rock samples. With the increase of the number of freeze–thaw cycles, the more serious and obvious is the failure and strength degradation. The number of secondary cracks after failure increases significantly and multiple groups of conjugate shear cracks are formed. With the increase of confining pressure, the damage accumulation rate of rock decreases with the increase of strain, and the rock gradually appears hardening characteristics. The failure mode of saturated sandstone gradually changes from splitting type to multi shear type and \"X\" conjugate shear type. The damage evolution equation considering the coupling effect of freeze–thaw and load is established, and the parameters of the model are identified and analyzed using the test data, which verifies the correctness of the model. The results of the study provide important reference for the evaluation of geotechnical stability in cold regions.

This study was to evaluate the effect of antifreeze peptides from pigskin collagen hydrolysates (CoAPPs) on the fermentation properties, texture properties, water distribution and water mobility of dough during freezing and freeze–thaw cycles. The fermentation properties of the frozen dough were more stable in the CoAPPs groups than those of control groups. The texture profile analysis showed that the hardness, gumminess and chewiness of the CoAPPs breads were significantly smaller ( P  < 0.05) than controls. The NMR showed that addition of CoAPPs weakened the influence of the freeze–thaw treatment on water mobility and influenced the water distribution in frozen dough. The results suggest that CoAPPs could potentially serve as a food-origin cryoprotectant in the conventional dough products.

Herein, we discuss changes in the emulsifying properties of myofibrillar protein (MP) because of protein denaturation and aggregation from quick-frozen pork patties with multiple fat levels and freeze–thaw (F–T) cycles. Protein denaturation and aggregation were confirmed by the significantly increased surface hydrophobicity, turbidity, and particle size, as well as the significantly decreased solubility and absolute zeta potential, of MPs with increases in fat levels and F–T cycles (p < 0.05). After multiple F–T cycles, the emulsifying activity and emulsion stability indices of all samples were significantly reduced (p < 0.05). The emulsion droplets of MP increased in size, and their distributions were dense and irregular. The results demonstrated that protein denaturation and aggregation due to multiple F–T cycles and fat levels changed the distribution of surface chemical groups and particle sizes of protein, thus affecting the emulsifying properties.

The solidification/stabilization (S/S) method is a common technique for the remediation of soils polluted by heavy metal. This study, thus, evaluated the long-term effectiveness, in term of the stabilization of lead in the solidified/stabilized soils, under freeze-thaw cycles, which are important physical processes that lead to material weathering. Three types of compound binders were obtained by mixing the three most commonly used binders (cement, quicklime, and fly ash) in varying proportions for the remediation of lead-contaminated soils. The leachability, chemical forms, and microstructure characteristics of the solidified/stabilized samples after various numbers freeze-thaw cycles (i.e., 0, 30, 90, and 180 times) were examined by utilizing the toxicity characteristic leaching procedure (TCLP) test, chemical speciation analysis, and scanning electron microscopy (SEM). The results showed that the long-term freeze-thaw cycles lead to decreased leachate pH and increased lead concentration in the leachate. The larger the total mix quantities of cement and quicklime, the lower the concentration of lead was presented in the leachate, however, indicating that cement and quicklime are more effective in immobilizing lead ions than fly ash. Chemical speciation analysis revealed that the long-term freeze-thaw cycles did, however, reduce the content of carbonate-bound form lead while the quantity of the ion-exchange forms. SEM further confirmed the observed leaching characteristics and chemical speciation characteristics. In addition, it indicated that, at the same number of freeze-thaw cycles, high initial lead concentrations substantially delayed the hydration process of cement in solidified lead-contaminated soil.

Granular materials in high-latitude cold and high-altitude areas are susceptible to damage and deterioration by freezing and thawing, which is directly caused by a change in microscopic pore structure, and moisture is the key factor. To investigate the unfrozen water change and storage characteristics of granular materials under freeze–thaw action, samples based on the soil–rock content were prepared, and freeze–thaw cycle tests were conducted. The evolution law of the unfrozen rate under freeze–thaw cycles was studied by low-field nuclear magnetic resonance (LF-NMR), and the evolution of pore and fissure spatial structure in granular samples was studied by three-dimensional X-ray microscopy (3D-XRM). The results show that nuclear magnetic signal intensity in the positive temperature region satisfies the linear fitting relation, and the average decrease in the unfrozen rate in the negative temperature region from − 1 to − 4 °C is more than 15%/°C. The freezing characteristic curve shows an exponentially decreasing trend and an overall left-bottom shift of the curve with increasing number of freeze–thaw cycles, implying that the pore space is more developed. The freeze–thaw cycle intensifies the hysteresis phenomenon. The slope of the unfrozen rate curve of the freeze–thaw process in the temperature range of 0 to − 10 °C is significantly greater than that in the temperature range of − 10 to − 35 °C and reaches a maximum in the temperature range of 0 to − 4 °C. The degree of freeze–thaw hysteresis increases significantly after the first five freeze–thaw treatments. The pore parameters of the dense sections decrease first and then increase, and the pore and fracture sections show a consistent trend with respect to the variation in the number of pore fractures, pore–fracture area, equivalent diameter, and surface porosity. The parameter values of the fracture sections are slightly higher than those of the pore sections under the same number of freezing–thawing cycles. The pore expansion effect is significant in the early freeze–thaw period; the average and maximum pore volumes increase first and then decrease slightly, and new micropores are mainly formed in the late freeze–thaw period. The freeze–thaw cycle effect destroys the weak surface of the internal structure through water–ice phase change frost heave and water migration erosion, causing granular accumulation instability.

To meet the requirements of durability design for concrete suffering frost damage, several test standards have been launched. Among the various damage indexes such as deteriorated compressive strength, relative dynamic elastic modulus (RDEM), residual deformation, etc., the concept of a “Durability Factor” (DF) is proposed by many standards to define the frost resistivity of concrete against frost action based on the experimental results from standard tests. Through a review of the literature, a clear tendency of strength/RDEM decay and residual deformation increase is captured with increasing cycles of freezing and thawing. However, tests following different standards finally derive huge scattering quantitative responses of frost resistance. Based on the large database of available laboratory experiments, this study presents a statistical analysis to propose a predictable model to calculate the DF with respect to other material factors. The statistical model is believed to be more convenient for engineering applications since the time-consuming experiment is no longer needed, and it is more precise compared with that developed according to only single experimental results to cover the uncertainties and unavoidable errors in specific tests. Moreover, the formula to calculate the DF is revised into a more general form so as to be applicable for all the laboratory experiments even for those cases without fully following the standards to derive a DF value.