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Renal transporters (cotransporters, channels, and claudins) mediate homeostasis of fluids and electrolytes and are targets of hormonal and therapeutic regulators. Assessing renal transporter abundance with antibody probes by immunoblotting is an essential tool for mechanistic studies. Although journals require authors to demonstrate antibody specificity, there are no consensus guidelines for kidney sample preparation leading to lab-to-lab variability in immunoblot results. In this study, we determined the impact of sample preparation, specifically freeze-thawed (Frozen) versus freshly processed (Fresh) kidneys (female and male rats and mice) on immunoblot signal detection of 15 renal transporters and the impact of protease inhibitors during homogenization. In female Sprague-Dawley rat kidneys homogenized with aprotinin, Na2EDTA, PMSF, and phosphatase inhibitors, immunodetection signals were ∼50% lower in Frozen versus Fresh samples for most transporters. Inclusion of additional inhibitors (Roche cOmplete Protease Inhibitor, "+") only partially increased transporter immunoblot signals to near Fresh levels. In male Sprague-Dawley rats, immunoblot signal density was lower in Frozen+ versus Fresh+ despite additional inhibitors. In C57BL/6 male mice, immunoblot signals from proximal tubule transporters were lower in Frozen versus Fresh by ∼25–50% and greater in Frozen+. In contrast, immunodetection signal was equivalent in female Frozen+ versus female Fresh+ for claudin 2, villin, AQP1, NKCC2, NCC, ENaCβ, ENaCɣ, claudin 7, AQP2, NKAα1, and NKAβ1. Thus, kidney sample preparation variables, including freeze-thaw and protease inhibition, have substantial transporter-specific effects on quantification of renal transporter abundance by immunoblot. These findings underscore the critical importance of assessing and reporting the impact of sample preparation protocols on transporter recovery to ensure robust rigor and reproducibility. NEW & NOTEWORTHY: Freeze-thawing kidneys before homogenization is widely accepted in renal research. This study demonstrates that if kidneys are freeze-thawed just once before homogenization, immunoblot signals are reduced in a transporter-specific manner in rats and mice dependent on sex and that immunoblot signals can be partially recovered by adding additional protease inhibitors. These findings underscore the critical importance of assessing the impact of sample preparation, including freeze-thaw versus fresh, to ensure robust rigor and reproducibility. [ABSTRACT FROM AUTHOR]

Understanding the triggering factors leading to rockfall is essential in managing their risk to transportation infrastructure. Precipitation and freeze-thaw (FT) are widely studied rockfall triggers, but developing reliable, quantitative methods to forecast rockfall in response to weather events remains challenging. Terrestrial laser scanning (TLS) is a powerful tool for high-accuracy modeling of rock slopes, but the frequency of scanning is often too low to correlate rockfall behavior with weather events or seasonal trends. We conducted a TLS campaign between 2017 and 2022 in Glenwood Canyon, Colorado, to investigate the seasonal variability in rockfall triggering and conditioning mechanisms. A total of 44 scans were collected over 5 years and were processed to allow for consistent detection of rockfalls larger than 0.0036 m3 in volume. Meteorological variables relating to precipitation, snowpack, and temperature were modeled using the National Weather Service SNODAS product and were used to complete an exploratory analysis of the correlation of various weather indices with rockfall rate over time. It was found that the short-term sum of liquid precipitation and snowmelt (averaged over the scanning interval or the max single-day total) was a strong predictor of rockfall volume rate between 2018 and 2020, especially in the spring and summer months; a linear model of max daily liquid was able to explain 65% of the variance (R2adj) in rockfall volume rate in March through August. This implicates springtime snowmelt and rain-on-snow events as strong predictors of rockfall at the study site. We interpret these observations to indicate that snowmelt and rainfall are acting to trigger blocks that have been conditioned (destabilized) over the preceding winter. [ABSTRACT FROM AUTHOR]

In this study, the possibility of using rubber waste particles (RWP) as a substitute for fine aggregate type in mortar, which can provide valuable results in reducing both natural resource consumption and environmental pollution, was evaluated in terms of engineering properties. Due to the dimensional proximity of RWP and fine aggregate and the physical properties of RWP, substitution of these two materials was used in this study. In the mortar produced in this study, 4 different mixtures were produced in which RWP was substituted with fine aggregate and sand at 0%, 5%, 7.5%, and 10% by volume. The binder dosage was kept constant at 550 kg/m3 and the water/cement ratio was 0.532. The changes in the mechanical properties (flexural tensile strength, compressive strength, and stress-strain) of the mixtures were evaluated after freeze-thaw cycles, a natural environmental effect. Prism specimens were subjected to compressive and tensile strength tests after 25, 50, 100, and 200 freeze-thaw (FT)-cycles, while the change in stress-strain behavior was studied on cube specimens after FT-cycles. The results showed that the losses in compressive and flexural tensile strength were in the range of 8%–27% and 5%–49%, respectively. Moreover, the load-displacement behavior varies with varying compressive strengths after different number of cycles. [ABSTRACT FROM AUTHOR]

Freeze-thaw resistance ability of concrete is an important issue when evaluating its durability. In this research, the objective was to predict concrete resistance to such cycles by analyzing water absorption based on the critical water saturation theory. In order to achieve this goal, detailed experiments were conducted, including water absorption, pore structure scanning, and mercury intrusion porosimetry of concrete with air-entraining admixture and different fiber content to obtain critical indicators, such as water absorption, porosity, and air void spacing factor, which formed the basis for predicting the service life of concrete. To predict the service life of concrete under freeze-thaw cycles, the critical saturation theory was utilized, taking into account environmental parameters and experimental indexes. The service life of concrete against freeze-thaw using air-entraining admixture and fibers had been calculated quantitatively in this paper. The results show that the predicted service life of concrete with air-entraining admixture was increased by more than 50 times, and using both air-entraining admixture and fiber could increase the service life by more than 80 times, even reaching 249 years. [ABSTRACT FROM AUTHOR]

Seasonal freeze–thaw (F–T) cycles significantly affect the mechanical properties of soils and the behavior of pile foundations in soils subjected to F–T cycles under different loading conditions. Soils exposed to F–T cycles can impact the performance of pile foundations. Consequently, the effects of F–T cycles should be taken into account when designing piles, particularly in cold regions such as Canada. In recent years, climatic conditions in Canada have changed due to global warming, increasing the number of F–T cycles in many regions each year. This study aimed to investigate the influence of different numbers of F–T cycles on the behavior of piles in sandy soils. Laboratory experiments were conducted on physical models of piles subjected to axial (uplift) and lateral loads combined with F–T cycles. The model was scaled using standard scaling principles, and the test apparatus was equipped with various sensors to measure temperatures, forces, and displacements. The results showed that as the number of F–T cycles increased, the lateral capacities of the piles under individual and combined loads increased steadily. The lateral load capacity increased from 350 to 430 N after five F–T cycles under individual loading and from 225 to 455 N after five F–T cycles under combined loading. However, the pile's uplift load capacity remained constant under individual and combined loads and there was no change due to F–T cycles. The results of this experimental study will be useful for understanding the behavior of piles subjected to seasonal F–T cycles and for improving the design of pile foundations in cold regions. [ABSTRACT FROM AUTHOR]

On February 17 2023, a landslide occurred on a highway slope along the Xiaolangdi Reservoir of the Yellow River, involving approximately 1,200 m3. This event directly resulted in road interruption and had profound social repercussions. This paper researches the landslide using a combination of field investigation, remote sensing imagery, laboratory tests, and numerical simulation. It traces the evolution of landslide occurrences influenced by human engineering activities and investigates the mechanisms by considering climatic factors, water levels fluctuations, and stress changes. The results indicate that: (1) fluctuations in water levels can reduce the stability coefficient of ancient landslides, albeit without directly triggering them. Moreover, alterations in soil stress induced by artificial excavation changes the distribution of the slope plastic zone, consequently altering potential sliding zones. (2) rainfall and temperature emerge as primary factors influencing the occurrence of accumulation landslides, it is particularly susceptible with the transition between winter and spring. (3) freeze-thaw action exerts significant pressure on sandstone bedding, which causes notable expansion deformation. Consequently, it is advisable to consider soil temperature and bedrock deformation when monitoring similar slopes. [ABSTRACT FROM AUTHOR]

Extrusion tests were conducted on recycled coarse aggregate concrete with circular steel tubes (RCCST, 100% replacement of recycled coarse aggregate) to investigate the impact of freeze–thaw cycles on bond properties. RCCST samples were subjected to 0, 25, 50, 75, 100, 125 and 150 freeze–thaw cycles and their bond properties were then compared with those of natural coarse aggregate concrete with circular steel tubes (NCCST) after 0, 100 and 150 freeze–thaw cycles. The experimental results indicate that freeze–thaw cycling damages the internal structure of RCCST, causing a significant decrease in interfacial bond strength with an increase in the number of freeze–thaw cycles. Freeze–thaw RCCST exhibits lower peak load and higher peak slip compared to NCCST, with increases of 25.2%, 73.2%, and 70.3% after 0, 100, and 150 freeze–thaw cycles, respectively. Regression analysis was used to derive an exponential equation that describes the relationship between longitudinal strain and strain gauge position. Additionally, a segmented fitting method was employed to obtain an expression for the bond slip of the freeze–thaw RCCST with a circular steel pipe. [ABSTRACT FROM AUTHOR]

Soil freeze-thaw (FT) cycles over agricultural lands are of great importance due to their vital role in controlling soil moisture distribution, nutrient availability, health of microbial communities, and water partitioning during flood events. Active microwave sensors such as C-band Sentinel-1 synthetic aperture radar (SAR) can serve as powerful tools to detect field-scale soil FT state. Using Sentinel-1 SAR observations, this study compares the performance of two FT detection approaches, a commonly used seasonal threshold approach (STA) and a computationally inexpensive general threshold approach (GTA) at an agricultural field in New Hampshire, US. It also explores the applicability of an interferometric coherence approach (ICA) for FT detection. STA and GTA achieved 85% and 78% accuracy, respectively, using VH polarization. We find a marginal degradation in the performance of STA (82%) and GTA (76%) when employing VV-polarized data. While there was approximately a 6 percentage point difference between STA's and GTA's overall accuracy, we recommend GTA for FT detection using SAR images at sub-field-scale over extended regions because of its higher computational efficiency. Our analysis shows that interferometric coherence is not suitable for detecting FT transitions under mild and highly dynamic winter conditions. We hypothesize that the relatively mild winter conditions and therefore the subtle FT transitions are not able to significantly reduce the correlation between the phase values. Also, the ephemeral nature of snowpack in our study area, further compounded by frequent rainfall, could cause decorrelation of SAR images even in the absence of a FT transition. We conclude that despite Sentinel-1's ~80% mapping accuracy at a mid-latitude site, understanding the cause of misclassification remains challenging, even when detailed ground data are readily available and employed in error attribution efforts. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the usability of the Leeb hardness test in determining changes in strength as a result of atmospheric weathering in works of cultural heritage built with low-strength pyroclastic rocks. To this end, the effects of weathering processes on strength properties were investigated in two building stones commonly used in Niğde province located in the Cappadocia (Turkey) region, which contains the most important works of cultural heritage created using low-strength pyroclastic rocks. The index, strength, mineralogical, and petrographic properties of rocks were first investigated. Then, freeze–thaw (F-T) and salt crystallization (SC) tests, the weathering processes of which consisted of six periods, were performed on samples prepared in cubic form. After the F-T and SC processes, the macro change in the samples and changes in weight loss, uniaxial compressive strength (UCS), and Leeb hardness (HL) values were determined. Highly correlated linear relationships were obtained between the SC and F-T cycles of the samples and the UCS and HL values. The HL test was applied to samples for which the UCS test could not be applied due to the loss of sample integrity after the advancing cycles of the accelerated weathering tests. Linear relationships with high correlation were determined between the UCS and HL values obtained from the samples after the accelerated weathering test. This study revealed that the HL approach could be used as an alternative in modeling the strength parameters of the weathering processes of the structures of cultural heritage built using low-strength rocks. [ABSTRACT FROM AUTHOR]

Copyright of Afyon Kocatepe University Journal of Science & Engineering / Afyon Kocatepe Üniversitesi Fen Ve Mühendislik Bilimleri Dergisi is the property of Afyon Kocatepe University, Faculty of Science & Literature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Soil & Water Conservation (1009-2242) is the property of Institute of Soil & Water Conservation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The timing and progression of the spring thaw transition in high northern latitudes (HNL) coincides with warmer temperatures and landscape thawing, promoting increased soil moisture and growing season onset of gross primary productivity (GPP), heterotrophic respiration (HR), and evapotranspiration (ET). However, the relative order and spatial pattern of these events is uncertain due to vast size and remoteness of the HNL. We utilized satellite environmental data records (EDRs) derived from complementary passive microwave and optical sensors to assess the progression of spring transition events across Alaska and Northern Canada from 2016 to 2020. Selected EDRs included land surface and soil freeze‐thaw status, solar‐induced chlorophyll fluorescence (SIF) signifying canopy photosynthesis, root zone soil moisture (RZSM), and GPP, HR, and ET as indicators of ecosystem carbon and water‐energy fluxes. The EDR spring transition maps showed thawing as a precursor to rising RZSM and growing season onset. Thaw timing was closely associated with ecosystem activation from winter dormancy, including seasonal increases in SIF, GPP, and ET. The HR onset occurred closer to soil thawing and prior to GPP activation, reducing spring carbon (CO2) sink potential. The mean duration of the spring transition spanned ∼6 ± 1.5 weeks between initial and final onset events. Spring thaw timing and maximum RZSM were closely related to active layer thickness in HNL permafrost zones, with deeper active layers showing generally earlier thawing and greater RZSM. Our results confirm the utility of combined satellite EDRs for regional monitoring and better understanding of the complexity of the spring transition. Plain Language Summary: The transition from winter to spring in high northern latitudes coincides with warming and thawing temperatures, the release of soil moisture, and the start of the growing season. The pattern of spring transition events is hard to monitor due to vast size and remoteness of Arctic tundra and boreal forest. Here, we used environmental data records (EDRs) from recent satellite observations (2016–2020) to map spring transition events across Alaska and Northern Canada. The EDRs included surface and soil freeze‐thaw status, soil moisture, vegetation productivity and soil respiration, and evapotranspiration. The EDRs were used to classify the timing and order of spring activation in these processes. Spring thawing was closely linked with increased soil moisture, which coincided with the start of growing season. Rising carbon dioxide (CO2) emissions from thawing soils generally preceded ecosystem uptake of CO2 from photosynthesis, reducing the spring carbon sink for atmosphere greenhouse gas emissions. On average, the spring transition spanned ∼6 weeks between initial and final onset events, with earlier timing in boreal forests than tundra. Earlier spring thawing and greater soil moisture levels also coincided with more extensive permafrost thawing. The satellite EDRs were effective in capturing multiple spring transition events and their climate sensitivity. Key Points: Satellite monitoring of complex of spring transition events in high northern latitudesSpring metrics linked with thaw‐related shifts in soil moisture and respiration, productivity, and water and energy fluxesSpring transition spans almost 6 weeks between initial landscape thaw and final growing season onset [ABSTRACT FROM AUTHOR]

[Objective] To investigate the effects of different straw returning methods on the temperature of black soil during seasonal freeze-thaw period. [Methods] By monitoring the field temperature, the soybean field was selected as the research object, and two types of returning methods were set, namely, straw mulching (FG) and straw mixing(FH). The amount of returned straw was 30% (59 670 kg/hm2), 60% (119 340 kg/hm2) and 90% (179 010 kg/hm2), respectively, and the bare land was designated as the control treatment (CK) in a total of seven treatments. Four soil depths of 5, 10, 20 and 30 cm below the surface along the vertical profile of soil were set to analyze the characteristics of soil temperature changes during the freezing and thawing period under different straw return methods and amounts. [Results] (1) Straw returning to the field resulted in the soil entering various freeze-thaw stages at a time lagging behind that of the bare land, and effectively raised the range of the minimum soil temperature and lowered the maximum temperature, of which both the maximum temperature raising and lowering occurred in the FG90 treatment, which were 3.0~6.1 ℃ and 1.5~5.2 ℃, respectively. (2) Straw returning weakened the soil temperature variability and correlation with air temperature. The maximum coefficient of variation and coefficient of variation and correlation occurred in the bare soil layer of 5 cm, which were 6.54 and 0.82, respectively. The minimum occurred in the 30 cm soil layer of the FG90 treatment, with values of 0.82 and 0.26, respectively. The relationship between soil temperature variability was CK>FG30>FH30>FH60>FG60> FH90>FG90, and the relationship between soil temperature and air temperature was CK>FH30>FG30>FH60>FH90>FG60>FG90>FG90. (3) The freezing and thawing rates of bare land were the highest and the freezing-thawing periods were the shortest, with a freezing rate of 0.19 ℃/h and thawing rate of 0.60 ℃/h. The minimum freezing rate occurred in FH90 treatment (0.04 ℃/h) and the minimum thawing rate occurred in FG90 treatment (0.05 ℃/h). (4) With the increase of soil depth, the soil freezing stage and thawing stage gradually increased, but the freezing duration gradually decreased. The effect of delaying freeze-thawing was most obvious in the FG90 treatment, with the freezing stage and thawing stage of 8 and 10 days, respectively. [Conclusion] The results of the research quantitatively described the temperature characteristics of black soil under different straw return measures during freezing and thawing periods, and clarified the differences in soil temperature effects between different straw return measures, which is of great significance in guiding the rational use of straw resources and conservation tillage in black soil areas.

This study investigates the dynamics of ice crystal growth and stress distribution in nanoconfined spaces using molecular dynamics simulations. First, the interaction between the pore wall and coarse‐grained water is modified, leading to the development of pore models with varying wettability. Subsequently, the process of ice crystal growth within pores of 10 nm diameter is examined under different temperatures and hydrophobicity conditions. Results unveil that ice crystal growth induces substantial energy and enthalpy alterations within the system. Hydrophobic nanopores demonstrate a protective function by limiting ice crystal growth and water transport, thereby mitigating freezing damage. However, hydrophobic nanopores exhibit increased stress levels when saturated with water. The study employs the Zener pinning theory and mass transfer rates to qualitatively scrutinize the thermodynamic and kinetic interplay between the ice crystal interface and the degree of supercooling. These findings offer insights into the mechanisms of ice formation and stress evolution in nanoconfined environments. [ABSTRACT FROM AUTHOR]

A parametric analysis of glue spall stress (concrete surface tensile stress at ice-discontinuities by differential thermal expansion ice-concrete) as affected by internal cracking in concrete in the CEN/TS 12390-9 salt-frost slab-test was made. Increasing differential thermal expansion ice-concrete (∆α) and reduced E-modulus and Poisson ratio (ν) due to internal cracking were used based on data from Part 1 of this study. For the concrete specimens in Part 1 of this study [1] glue spall stress increased by 14 % due to internal cracking whereas reduced ice thickness of 1 – 2 mm due to accelerated Liquid Uptake (LU) in wet freeze/thaw reduced glue spall stress by 34 to 65 %. LU should hence be accounted for in modelling scaling, both due to reduced ice thickness and increased ∆α due to internal cracking. Increased crack penetration depth and its effect on scaled particle size due to internal cracking were also analyzed.

In the development of mineral resources and engineering construction in the western region, sandstone is one of the main engineering geological aquifers, and the freezing and thawing environment affects the mechanical and deformation characteristics of sandstone. In order to study the deterioration and damage characteristics of mechanical properties of loaded rocks under the influence of freeze-thaw environment, red fine sandstone in Shaanxi province was taken as the research object, and freeze-thaw cycle tests and uniaxial compression tests were carried out for 0, 5, 10, 20 and 30 times, and the stress-strain curve and mechanical characteristic parameters of the whole uniaxial compression process of frozen-thawed sandstone were obtained. The mechanical characteristic parameters of frozen-thawed rocks were analyzed, and the deterioration model of rock mechanical properties under freeze-thaw environment was established. Based on the influence of freeze-thaw environment on rock damage, considering the characteristics of rock compaction stage in deformation stage, a modified statistical damage constitutive model considering compaction stage is established. The results show that with the increase of freeze-thaw cycles, the proportion of rock compaction stage is increasing, and the peak value should also increase gradually. Brittle failure occurs in the first 30 freeze-thaw cycles, and the brittleness of rock is obviously weakened after 30 freeze-thaw cycles, and the strain softening stage is obvious. The loss rate of mechanical characteristic parameters increased rapidly in the first 10 times of freeze-thaw cycle, and then slowed down obviously. After 30 freeze-thaw cycles, the peak strength loss rate is 47.27% and the elastic modulus loss rate is 60.35%. Among them, the loss rate of mechanical characteristic parameters increases linearly with the number of freeze-thaw cycles, and the mechanical properties of rocks decrease exponentially after freeze-thaw. The peak strength and elastic modulus of rocks under freeze-thaw environment can be accurately predicted by using the pore characteristics of rocks under freeze-thaw environment. The modified statistical damage constitutive model considering the compaction stage has a higher fitting degree with the test curve, and the modified theoretical model can provide reference for the deterioration of mechanical properties and damage prediction of frozen-thawed rocks.

The failure of rock in cold regions due to repeated freeze–thaw (F-T) cycles and periodic load-induced fatigue damage presents a significant challenge. This study investigates the evolution of the multi-scale structure of fractured granite under combined freeze–thaw (F-T) cycles and periodic loading and develops a constitutive damage model. The results indicate that after F-T cycles, network cracks develop around pre-existing cracks, accompanied by block-like spalling. After applying the fatigue load, the nuclear magnetic resonance (NMR) T2 spectrum shifts to the right, significantly increasing the amplitude of the third peak. The freeze–thaw process induces a "liquid–solid" phase transition, weakening the original pore structure of the rocks and leading to meso-damage accumulation. The pores in fractured granite progressively enlarge and interconnect, reducing the rock's load-bearing capacity and fatigue resistance. The combined effects of F-T cycles and periodic loading induce particle movement and alter fracture modes within the rock, subsequently affecting its macro-damage characteristics. The theoretical curves of the constitutive model align with the experimental data. The findings can serve as a theoretical reference for preventing and controlling engineering disasters in fractured rock masses in cold regions. [ABSTRACT FROM AUTHOR]

The freeze-thaw process is a weathering phenomenon that occurs in rocks and stones when water enters small cracks and pores within the stone. When the temperature drops below freezing, the water inside the rock expands as it freezes, exerting pressure on the rock from within. In this study the effect of freeze thaw on mechanical parameter uniaxial compression strength (UCS) and ultrasonic pulse velocity (UPV) of 47 oolitic samples were considered. At first, capillary absorption for cylindrical and prismatic oolitic samples were measured and then freeze-thaw experiment with 23 cycles were applied to the samples. UPV of samples before and after freeze-thaw was analysed by two ultrasonic devices including Geotron and Pundit. It was observed that freeze thaw decreases primary velocity (Vp) and secondary velocity (Vs) by around 20 and 7% respectively. However, average UCS of 1.6 MPa indicates strength decrease of samples, which represent negative effect of pore expansion due to freeze thaw on strength parameter of samples. [ABSTRACT FROM AUTHOR]

In regions with sandy soft soil strata, the subway foundation commonly undergoes freeze–thaw cycles during construction. This study focuses on analyzing the microstructural and fractal characteristics of frozen–thawed sandy soft soil to improve our understanding of its strength behavior and stability. Pore size distribution curves before and after freeze–thaw cycles were examined using nuclear magnetic resonance technology. Additionally, fractal theory was applied to illustrate the soil's fractal properties. The strength properties of frozen remolded clay under varying freezing temperatures and sand contents were investigated through uniaxial compression tests, indicating that soil strength is significantly influenced by fractal dimensions. The findings suggest that lower freezing temperatures lead to a more dispersed soil skeleton, resulting in a higher fractal dimension for the frozen–thawed soil. Likewise, an increase in sand content enlarges the soil pores and the fractal dimension of the frozen–thawed soil. Furthermore, an increase in fractal dimension caused by freezing temperatures results in increased soil strength, while an increase in fractal dimension due to changes in sand content leads to a decrease in soil strength. [ABSTRACT FROM AUTHOR]

Snake gourd is a seasonal vegetable with a high water content and medicinal value, but the short harvest period limits the large-scale application of snake gourd. Therefore, the effects of freeze–thaw pretreatment (FT) combined with hot air (HD) on the drying characteristics, active ingredients and bioactivities of snake gourd were investigated. The results showed that FT pretreatment reduced browning and shortened the drying time by 44%; the Page model was the best fit for describing the drying process. The polysaccharide contents (21.70% in alcoholic extract (TG1) and 44.34% in water extract (TG2)) and total phenol contents (1.81% in TG1 and 0.88% in TG2) of snake gourd pretreated by FT-HD were higher than those of snake gourd pretreated by the corresponding HD treatment. The FT pretreatment decreased the molecular weight of snake gourd polysaccharides and increased the molar ratio of glucose. The extracts pretreated by FT-HD showed greater chemical, cellular antioxidant capacity and α-amylase and α-glucosidase inhibition than those pretreated by HD. FT-HD can be recommended for achieving a short drying time and high quality of snake gourd and can be used for the drying of other fruits and vegetables. [ABSTRACT FROM AUTHOR]

AbstractFreeze temperature and ice quantity formed inside porous media has been investigated on limestone tilestone samples by Differential Scanning Calorimetry (DSC) measurements. The aim was to determine the role of these stone frost features on limestone damage to Freeze-Thaw (FT) cycles, in relation to the presence of stylolite inside their structure. In fact, the presence of stylolite inside the structure leads to increase locally the pore rate and size, with connected pores. This implies a local increase of ice quantity formed at the surround of stylolite. Damage is thus associated to a heterogeneous nucleation, a rapid growth and ice-front propagation inside pores induced by the presence of stylolite. Specimens exhibiting an increase of quantity of ice formed inside their stylolite – of more than 30% compared to host rock – were damaged by freeze/thaw cycles. Furthermore, stones with freezing temperature lower than the minimum of FT cycles temperature are frost resistant. Finally, low-temperature calorimetry appears to be a practical and cheap method for quickly assessing frost limestone susceptibility. For example, this method can benefit some modest heritage constructions in UNESCO World Heritage site ‘Causse & Cevennes’, made by craftsmen who need to quickly know the frost resistance of the stones they use. [ABSTRACT FROM AUTHOR]

The global challenge faced due to the impact of the construction industry on climate change, along with the issues surrounding sustainable waste disposal, has necessitated various research on using waste products as eco-friendly alternatives in construction. In this study, the avoidance of waste disposal through landfills in Australia was encouraged by incorporating lime kiln dust (LKD) and tire rubber waste (TRW) into masonry mixes to manufacture green bricks. Furthermore, the investigations in this article highlight the use of mercury intrusion porosimetry (MIP) to determine the durability of the LKD-TRW bricks when exposed to freeze–thaw (F-T) cycles by examining the pore size distribution within the bricks. The LKD waste was blended with ground granulated blast furnace slag (GGBFS) at a 70:30 blending ratio and combined with the TRW in stepped increments of 5% from 0 to 20% to produce these eco-friendly bricks. The compressive strength (CS), flexural strength (FS), frost resistance (FR), pore size distribution according to mercury intrusion porosimetry (MIP), and the water absorption (WA) properties of the bricks were assessed. The CS and FS values at 28 days of curing were recorded as 6.17, 5.25, and 3.09 MPa and 2.52, 2, and 1.55 MPa for 0, 5, and 10% TRW contents, respectively. Durability assessments using the F-T test showed that the bricks produced with 0% TRW passed as frost-resistant bricks. Furthermore, the results from the MIP test showed a total pore volume of 0.033 mL/g at 3 µm pore size for the 0% TRW content, further confirming its durability. Hence, the 0% LKD-TRW bricks can be utilized in cold regions where temperatures can be as low as −43 °C without deteriorating. Lastly, WA values of 7.25, 11.76, and 14.96% were recorded for the bricks with 0, 5, and 10% TRW, respectively, after the 28-day curing period. From all of the results obtained from the laboratory investigations, the LKD-TRW bricks produced with up to 10% TRW were within the satisfactory engineering requirements for masonry units. [ABSTRACT FROM AUTHOR]

The inferior mechanical performance and freeze–thaw (FT) resistance of recycled concrete are mostly due to the significant water absorption and porosity of recycled coarse particles. In this study, different dosages of zeolite powder were used in recycled concrete. A series of macroscopic tests were used to evaluate the workability and FT durability of zeolite powder-modified recycled concrete (ZPRC). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to reveal the micro-mechanisms of FT resistance in ZPRC. The results show that the increase in zeolite powder content leads to a decrease in the slump and water absorption of ZPRC. Additionally, ZPRC with 10% zeolite powder has superior mechanical characteristics and tolerance to FT conditions. The higher strength and FT resistance of the ZPRC can be attributed to the particle-filling effect, water storage function, and pozzolanic reaction of zeolite powder, which results in a denser microstructure. The particle-filling effect of zeolite powder promotes the reduction of surface pores in recycled coarse aggregates (RCAs). The water storage function of zeolite powder can provide water for the secondary hydration of cement particles while reducing the free water content in ZPRC. The pozzolanic reaction of zeolite powder can also promote the generation of hydrated calcium silicate and anorthite, thereby making the microstructure of ZPRC more compact. These results provide theoretical guidance for the engineering application of recycled concrete in cold regions. [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]

Copyright of International Journal of Engineering Research & Development (IJERAD) is the property of International Journal of Engineering Research & Development and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Engineering Research & Development (IJERAD) is the property of International Journal of Engineering Research & Development and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The glacial history of Pico de Orizaba indicates that during the Last Glacial Maximum, its icecap covered up to ∼3000 m asl; due to the air temperature increasing, its main glacier has retreated to 5050 m asl. The retraction of the glacier has left behind an intense climatic instability that causes a high frequency of freeze-thaw cycles of great intensity; the resulting geomorphological processes are represented by the fragmentation of the bedrock that occupies the upper parts of the mountain. There is a notable lack of studies regarding the fragmentation and erosion occurring in tropical high mountains, and the associated geomorphological risks; for this reason, as a first stage of future continuous research, this study analyzes the freezing and thawing cycles that occur above 4000 m asl, through continuous monitoring of surface ground temperature. The results allow us to identify and characterize four zones: glacial, paraglacial, periglacial and proglacial. It was found that the paraglacial zone presents an intense drop of temperature, of up to ∼9°C in only sixty minutes. The rock fatigue and intense freeze-thaw cycles that occur in this area are responsible for the high rate of rock disintegration and represent the main factor of the constant slope dynamics that occur at the site. This activity decreases, both in frequency and intensity, according to the distance to the glacier, which is where the temperature presents a certain degree of stability, until reaching the proglacial zone, where cycles are almost non-existent, and therefore there is no gelifraction activity. The geomorphological processes have resulted in significant alterations to the mountain slopes, which can have severe consequences in terms of risk and water. [ABSTRACT FROM AUTHOR]

Cyanobacterial phycocyanin pigment is widely utilized for its properties in various industries, including food, cosmetics, and pharmaceuticals. Despite its potential, challenges exist, such as extraction methods impacting yield, stability, and purity. This study investigates the impact of the number of freeze–thaw (FT) cycles on the extraction of phycocyanin from the wet biomass of four cyanobacteria species (Arthrospira platensis, Chlorogloeopsis fritschii, Phormidium sp., and Synechocystis sp.), along with the impact of five extraction solutions (Tris-HCl buffer, phosphate buffer, CaCl2, deionized water, and tap water) at various pH values. Synechocystis sp. exhibited the highest phycocyanin content among the studied species. For A. platensis, Tris-HCl buffer yielded maximum phycocyanin concentration from the first FT cycle, while phosphate buffer provided satisfactory results from the second cycle. Similarly, Tris-HCl buffer showed promising results for C. fritschii (68.5% of the maximum from the first cycle), with the highest concentration (~12% w/w) achieved during the seventh cycle, using phosphate buffer. Phormidium sp. yielded the maximum pigment concentration from the first cycle using tap water. Among species-specific optimal extraction solutions, Tris-HCl buffer demonstrated sufficient extraction efficacy for all species, from the first cycle. This study represents an initial step toward establishing a universal extraction method for phycocyanin from diverse cyanobacteria species. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of freeze-thaw cycles on the performance of asphalt mixtures containing 60% rejuvenated asphalt pavement (RAP). Two rejuvenation processes, traditional and bio-graded recycling, are compared regarding high-temperature performance, low-temperature performance, dynamic stability, flexural tensile strength, split tensile strength, water stability, and fatigue performance after various freeze-thaw cycles. The results indicate that bio-graded rejuvenation, compared to traditional rejuvenation, effectively enhances the high-temperature performance, low-temperature performance, water stability, and fatigue performance after freeze-thaw cycles. Both rejuvenations initially meet the dynamic stability requirements but show a decreasing trend with increasing freeze-thaw cycles, with traditional rejuvenation exhibiting more severe degradation. The flexural tensile strength initially exceeds that of conventional asphalt mixtures but decreases significantly with freeze-thaw cycles, especially in traditional rejuvenation. Additionally, freeze-thaw action increases the internal void ratio, affecting water stability and anti-freezing ability, particularly in traditional rejuvenated mixtures. These findings underscore the impact of freeze-thaw cycles on rejuvenated asphalt mixtures and emphasize the importance of innovative rejuvenation techniques for sustainable pavement. [ABSTRACT FROM AUTHOR]

In recent years, asphalt pavement has been subjected to varied environmental conditions during its service life, conditions that predispose it to deformation and cracking. To enhance the performance of asphalt pavement, rock asphalt has been selected as a modifier due to its good compatibility with virgin asphalt binder and its ability to improve the fatigue cracking resistance of asphalt mixtures. Although scholars have conducted some studies on rock asphalt mixtures, research on the fatigue and self-healing performance of these mixtures under conditions such as ultraviolet (UV) aging and freeze–thaw remains limited. This paper presents findings from a study that employs a combined fatigue-healing test to assess the impact of such complex environmental factors on the fatigue and self-healing properties of fine aggregate matrix (FAM) mixtures containing three types of rock asphalts, i.e., Buton, Qingchuan (QC), and Uintaite Modifier (UM). The analysis of fatigue-healing test results, grounded in viscoelastic continuum damage (VECD) theory, indicates that rock asphalt can extend the fatigue life of FAM mixtures, albeit with a concomitant decrease in their self-healing capabilities. The study further reveals that UV aging, freeze–thaw, and UV aging–freeze–thaw conditions all led to a diminution in the fatigue and self-healing properties of FAM mixtures. However, FAM mixtures containing rock asphalt demonstrated greater resilience against these reductions. Atomic force microscope (AFM) results indicate that UV aging reduced the number of bee-structures and enlarged their area, whereas the incorporation of rock asphalt enhanced the uniformity of these structures' distribution, thereby improving the fatigue cracking resistance of FAM mixtures. Fourier transform infrared spectroscopy (FTIR) analysis reveals that while UV aging increased the carbonyl and sulfoxide indices within the asphalt binder, rock asphalt is effective in mitigating this effect to a certain degree, thereby enhancing the aging resistance of FAM mixtures. [ABSTRACT FROM AUTHOR]

Red mud (RM) is an industrial waste generated in the process of aluminum refinement. The recycling and reusing of RM have become urgent problems to be solved. To explore the feasibility of using RM in geotechnical engineering, this study combined magnesium oxide (MgO) (or calcium oxide (CaO)) with RM as an RM-based binder, which was then used to stabilize the soil. The physical, mechanical, and micro-structural properties of the stabilized soil were investigated. As the content of MgO or CaO in the mixture increased, the unconfined compressive strength (UCS) of the RM-based cementitious materials first increased and then decreased. For the soils stabilized with RM–MgO or RM–CaO, the UCS increased and then decreased, reaching a maximum at RM:MgO = 5:5 or RM:CaO = 8:2. The addition of sodium hydroxide (NaOH) promoted the hydration reaction. The UCS enhancement ranged from 8.09% to 66.67% for the RM–MgO stabilized soils and 204.6% to 346.6% for the RM–CaO stabilized soils. The optimum ratio of the RM–MgO stabilized soil (with NaOH) was 2:8, while that of the RM–CaO stabilized soil (with NaOH) was 4:6. Freeze–thaw cycles reduced the UCS of the stabilized soil, but the resistance of the stabilized soil to freeze–thaw erosion was significantly improved by the addition of RM–MgO or RM–CaO, and the soil stabilized with RM–MgO had better freeze–thaw resistance than that with RM–CaO. The hydrated magnesium silicate generated by the RM–MgO stabilized soil and the hydrated calcium silicate generated by the RM–CaO stabilized soil helped to improve the UCS of the stabilized soil. The freeze–thaw cycles did not weaken the formation of hydration products in the stabilized soil but could result in physical damage to the stabilized soils. The decrease in the UCS of the stabilized soil was mainly due to physical damage. [ABSTRACT FROM AUTHOR]

Snowmelt runoff and soil freezing have been combined to seriously exert on the rill networks and soil erosion intensity in the black soil region of northeastern China. The dynamic development of rill networks can be used to quantitatively extract the parameters of erosion. Previous studies have focused primarily on the runoff erosion caused by rainfall. Only a few studies were to consider the combined effects of snowmelt runoff and freezing. Currently, available methods cannot fully meet the high precision of rill morphology. Therefore, it is very necessary to systematically investigate the rill erosion under combined effects using high-precision extraction. This study aims to simulate the snowmelt runoff scouring on the frozen (-20°C freezing) and non-frozen slopes (10°C), refilled with black soil from northeastern China. A 0°C ice-water mixture was used to simulate the snowmelt runoff scouring. Meanwhile, three-dimensional laser scanning was employed to obtain the point cloud data of the slope surface after different times of scouring, until the eroded surface stabilized. The Digital Surface Model (DSM) of Difference (DoD) with point cloud reverse engineering was used to detect and parameterize the micro-topographic pattern (e.g., development of rill networks and erosion area, erosion volume, rill length, and rill density). The results show that there was a significant impact of freezing-induced temperature on the development of rill networks: (1) The frozen slope was more prone to develop the rill networks. The erosion rate after each scouring was significantly higher than that on the nonfrozen slopes. Upon reaching stability, the erosion area, erosion volume, and rill length were 291%, 557%, and 437% of those on the non-frozen slopes, respectively; (2) The cumulative erosion volume of the frozen and non-frozen slopes showed similar patterns during the rill development. But there were noticeable differences along the cross-sectional direction of the rills. On the frozen slopes, the width-depth ratio (RW/D) of the rill cross-sections decreased rapidly at the rill intersections with accelerated downcutting, whereas, the width and depth of rills increased linearly and stably. On the non-frozen slopes, the RW/D at the midslope cross-sections increased with the number of scouring events, thus accelerating lateral erosion, while the RW/D at other sections decreased with the number of scouring events with accelerated downcutting; (3) The relative error range was -12.70% to 4.42% for the Differential Digital Surface Model (DoD) with ArcGIS hydrological processing and GeoMagic point cloud reverse engineering models for the frozen slopes, with an absolute mean relative error of 5.48%, and an extraction accuracy of over 94%. The combined extraction with GeoMagic and ArcGIS showed a great contribution to obtain the rill parameters on the freeze-treated slopes. The finding can serve as a promising potential to the rill development under complex eroding settings. [ABSTRACT FROM AUTHOR]

Freeze-thaw cycles significantly impact construction by altering soil properties and stability, which can lead to delays and increased costs. While soil-stabilizing additives are vital for addressing these issues, stabilized soils remain susceptible to volume changes and structural alterations, ultimately reducing their strength after repeated freeze-thaw cycles. This study aims to introduce a different approach by employing magnesium chloride (MgCl2) as an antifreeze and soil stabilizer additive to enhance the freeze-thaw resilience of clay soils. We investigated the efficiency of MgCl2 solutions at concentrations of 4%, 9%, and 14% on soil by conducting tests such as Atterberg limits, standard proctor compaction, unconfined compression, and freeze-thaw cycles under extreme cold conditions (−10 °C and −20 °C), alongside microstructural analysis with SEM, XRD, and FTIR. The results showed that MgCl2 reduces the soil's liquid limit and plasticity index while enhancing its compressive strength and durability. Specifically, soil treated with a 14% MgCl2 solution maintained its volume and strength at −20 °C, with similar positive outcomes observed for samples treated with 14% and 9% MgCl2 solutions at −10 °C. This underlines MgCl2's potential to enhance soil stability during initial stabilization and, most importantly, preserve it under cyclic freeze-thaw stresses, offering a solution to improve construction practices in cold environments. [ABSTRACT FROM AUTHOR]

In order to study the influencing factors of the development of freeze-thaw temperature field in cement improved soil layer, this paper takes the freezing project of a subway tunnel in Guangzhou Metro Line 3 as the background, simulates the freeze-thaw temperature field of the tunnel through the coupling of water and heat, studies the influence law of the whole process development of the freeze-thaw temperature field, and proves the accuracy of the model by comparing with the measured data. The influence of thermal conductivity, volume heat capacity, original ground temperature, cement content and other factors on the freeze-thaw temperature field is analyzed. The results show that during the whole process of freeze-thaw temperature field development, the soil is greatly cooled first, and after forming a stable freezing curtain, the cooling rate slows down, and the thickness of the effective freezing wall increases slowly. After entering the natural thawing stage, the temperature rises rapidly until it reaches the phase transition stage. After a long period of time in this stage, the soil quickly returns to positive temperature. The influence of different factors on the freezing temperature field is analyzed. The volume heat capacity of the soil and the original ground temperature are negatively correlated with the freezing effect of the freezing temperature field, and have little effect on the natural thawing temperature field. The decrease of thermal conductivity of soil will inhibit the development of freezing temperature field, but it can shorten the period of natural thawing. When the cement content is 12 %, the soil freezing effect is the best, and the development rate of the thaw settlement temperature field is the fastest, and the natural thawing period is the shortest. [ABSTRACT FROM AUTHOR]

The freeze–thaw (F-T) cycle is one of the weathering factors that can cause rapid deterioration of the mechanical properties of rocks and threaten the stability and durability of rock engineering in cold regions. To study the influence of F-T action on the mechanical and deformation characteristics of sandstone, triaxial compression tests were performed under four confining pressures (0, 1, 3, and 5 MPa) and five F-T cycles (0, 40, 80, 120, and 160). The experimental results show that the stress–strain curves of the sandstone after F-T cycles can be divided into four phases: compaction, elasticity, strain-hardening, and postpeak failure. According to the deformation behaviors of the sandstone with various F-T cycles, an elastoplastic damage constitutive equation was established considering the compaction effect and F-T action. The model parameters were determined, and the theoretical curves were calculated. The comparisons with theoretical and experimental stress–strain curves demonstrate that the formulated constitutive equation can reflect the key deformation stages and mechanical behaviors of sandstone with different F-T cycles. Because the damage variable is introduced in establishing the model, the proposed model can also provide a quantitative description of the macrodamage, which agrees well with the microdamage of the sandstone after many F-T cycles measured by acoustic emission (AE) technology. The formulated constitutive equation in this paper can well describe the experimental deformation curves of sandstone with various F-T cycles and is easy to embed into numerical analysis software. The results can provide a certain theoretical reference for the evaluation of the durability and stability of rock engineering structures impacted by F-T-induced damage in cold regions. [ABSTRACT FROM AUTHOR]

Soil washing has been widely applied and studied in the remediation of heavy metal contamination soil. However, it proves easily limited by soil texture. To this end, the method of freeze-thaw and washing is used to enhance washing efficiency of clayey soils. An array of experiments of laboratory indirectness washing and freeze-thaw and washing were carried out to investigate the removal effect of single and compound washing on heavy metals. The results showed that the stability of soil aggregates would be destabilized by repeated freezing and thawing, contributing to a sufficient contact reaction between eluents and contaminations. The process can also remove heavy metals under a lower liquid-solid ratio, thus reducing the risk of secondary contamination of the soil environment. The eluent has a certain viscosity, which increases the viscosity of the pore water. Accordingly, the water migration resistance increases and inhibits the soil frost heaving-water intake, resulting in the reduction of removal efficiency. The removal effect of compound washing is preferable to the single washing, proving effectively removing the weak acid extractable fractions, reducible fractions, as well as residue fractions of Cd and the weak acid extractable fractions and reducible fractions of Pb in the soil. The research results provide a novel method of reusing natural cold energy to remedy clayey soil contamination with heavy metals. [ABSTRACT FROM AUTHOR]

Copyright of Water Conservancy Science & Techonlogy & Economy is the property of Water Conservancy Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Disasters occurring at loess slopes in seasonal frozen regions are closely related to changes in the thermo-hydro-mechanical (THM) state in loess by freeze-thaw (FT) action. Current research on FT-induced soil slope failure focuses on frozen stagnant water effects, while the intrinsic connection between the FT-induced stagnant water effect and soil strength deterioration remains unclear. In this study, by taking the FT-induced loess slope failure as an example, field surveys, boreholes, exploratory wells, and 3D topographic mapping were used to reveal the landslide features and stratigraphic information; Furthermore, the temporal and spatial variation of water and heat in loess slope was revealed by on-site monitoring data; A THM coupled model of frozen soil was established using COMSOL Multiphysics simulation software to reconstruct the frozen stagnant water process of shallow loess slope, as well as the influence of THM field on loess landslide. The results show that the effects of FT in the seasonally frozen region occurred in the shallow layer of the loess slope. The water-ice phase transition during FT process broke the phase equilibrium of loess. Numerical calculations and field monitoring indicated a continuous migration of water to the freezing front, creating a water-enriched zone inside the loess. Both the impact of the frozen stagnant water and changes in the stress field led to the degradation of loess structure and reduced the strength properties, thus threatening the stability of the loess slope. The study results can contribute to an in-depth understanding of the mechanism underlying FT loess landslides in seasonal frozen regions, and provide a scientific basis for the evaluation and prevention of FT landslides. [ABSTRACT FROM AUTHOR]

The hydraulic concrete in the alpine region is subjected to alternating actions of freeze–thaw (F) and abrasion (W) during operation, resulting in significant deterioration of concrete durability. In this paper, the water/binder ratio (W/B) was employed as the test variable, the working condition F group and W group were set as the control group, and the working condition F-W group was used as the test group. Fast-freezing and underwater methods are used for the alternating test. By measuring the mass loss, relative dynamic elastic modulus (RDEM), surface morphological characteristics, fractal dimension of concrete in each alternating cycle, and the evolution law of concrete performance under the alternating action of F and W was explored. The results show that compared with the control group, the alternating action will accelerate the mass loss of concrete, reduce the RDEM, and cause the deterioration of surface wear. The maximum increase in mass loss and RDEM of concrete is 1.92% and 20.11%, respectively. During this process, the fractal dimension of the concrete increases as the number of alternating cycles increases, but it still does not exceed the limit of 2.4. In addition, a relationship function between the fractal dimension and the mass loss rate, volume loss, was established. It was found that the experimental group had a good linear correlation, and the correlation was close to 95%, which was about 20% higher than that of the control group. [ABSTRACT FROM AUTHOR]

An indoor accelerated freezing and thawing test of polypropylene fibre-reinforced concrete in chloride and sulphate environments was conducted using the "fast-freezing method" with the objective of investigating the damage law of the post-freezing mechanical properties of hydraulic concrete structures and studying the effects of different mixing amounts of polypropylene fibres on the mechanical properties of concrete. Furthermore, in order to reduce the cost of concrete tests and shorten the time required for conducting concrete tests, a backpropagation neural network based on a Beetle Antenna Search algorithm (BAS-BPNN) was established to simulate and predict the mechanical properties of polypropylene fibre-reinforced concrete. The accuracy of the model was verified. The results indicate that the order of improvement in the macro-physical properties of concrete due to fibre doping is as follows: PPF1.2 exhibited the greatest improvement in macro-physical properties of concrete, followed by PPF0.9, PPF1.5, PPF0.6, and PC. When the freezing and thawing medium and the number of cycles are identical, all four assessment indexes (R2, RMSE, SI, MAPE) demonstrate that the four groups of polypropylene fibre concrete exhibit superior performance to the control group of ordinary concrete. This indicates that polypropylene fibre can enhance the mechanical properties and freezing resistance of the concrete matrix, delay the process of freezing and thawing damage to the matrix, and extend the lifespan of the matrix, yet cannot prevent the ultimate failure of the matrix. The application of intelligent algorithms to optimise the parameters of an artificial neural network model can enhance its capacity to generalise and predict the mechanical properties of concrete. In terms of the coefficient of determination (R2), the Beetle Antenna Search algorithm (0.9782) outperforms the Particle Swarm Optimization (PSO; 0.9676), the Genetic Algorithm (GA; 0.9645), and the backpropagation neural network (BPNN; 0.9460). The improved backpropagation neural network based on the Beetle Antenna Search algorithm not only avoids the trap of local optimality but also improves the model accuracy while further accelerating the convergence speed. This approach can address the complexity, non-linearity, and modelling difficulties encountered during the freezing process of concrete. Moreover, it offers relatively accurate prediction outcomes at a reduced cost in comparison to traditional experimental methodologies. [ABSTRACT FROM AUTHOR]

Crops are often affected by NaCl, giant ragweed (Ambrosia trifida L.) and freeze-thaw stress simultaneously during their growth, and many areas in Northeast China are facing such serious ecological stress problems. In this experiment, the physiological responses of rye seedlings to NaCl and A. trifida extract stressor (AES) in a freeze-thaw environment were studied by artificial simulation technique. Malondialdehyde (MDA) content, soluble protein (SP) content, superoxide dismutase (SOD) activity, catalase (CAT) activity, net photosynthetic rate (Pn) and transpiration rate (Tr) were determined and analyzed. The results showed that: After stress treatment, MDA and SP contents of rye seedlings increased by 19.48%-88.96% and 22.54%-107.30%, SOD and CAT activities increased by 4.42%-26.60% and 23.31%-64.68% and Pn and Tr decreased by 40.00%-71.67% and 20.00%-80.00%. In the face of stress, rye seedlings can reduce the damage caused by stress by increasing osmotic substance and antioxidant enzyme activity, so as to adapt to the environment. The results revealed that combined NaCl, AES and freeze-thaw stress had a significant superposing effect on plants compared with single NaCl, AES and freeze-thaw stress. Net photosynthetic rate (Pn) and transpiration rate (Tr)as photosynthetic indices, are easily affected by the environment, and the photosynthetic physiological characteristics of plants will decrease significantly under external stress. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To investigate the effect of freeze-thaw (FT) process on the yield and quality of tiger nut oil, tiger nuts were subjected to 0–12 cycles of FT treatment. Results indicated that FT treatment ruptured the cell structure of tiger nut, resulting in an increase in oil yield. Acid value (2.09–2.42 mg KOH/g) and peroxide value (0.40–0.42 mmol/kg) increased with the number of FT cycles, but the increments were small. Likewise, slight differences in fatty acid composition and thermal properties between control and FT-treated samples were observed. FT treatment remarkably increased the bioactive components (e.g., vitamin E, sterols, chlorophyll and carotenoids) in the oil and extended the oxidation induction time from 1.2 to 5.57 h. FT treatment altered the volatile composition of tiger nut oil, increasing the relative content of heterocycles and pyrazines such as 2-methoxy-4-vinylphenol, trimethylpyrazine and tetramethylpyrazine. It was suggested that FT treatment prior to oil extraction was beneficial to improve the oil yield and quality.