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The present work addresses the systematic accurate fabrication and design of biphilic surfaces having superhydrophobic circular islands surrounded by a hydrophilic background by investigating their condensation frosting and defrosting behavior. A significant delay in frost formation is observed on samples with higher superhydrophobicity ratio A*, defined as superhydrophobic area to total area ratio. As the superhydrophobic island diameter D increases from D = 500 µm to D = 700 µm (A* from 19.62% to 38.46%), a 50% improvement/delay is observed in terms of frost formation or densification. Besides delaying icing/frosting, the presence of superhydrophobic areas empowers the formation of porous and nonuniform frost structure, which facilitates ice removal during the defrosting process. To this end, as the surface is recovered the ambient temperature, almost complete passive cleaning performance within only 23 s is observed on the biphilic design having superhydrophobic islands with the diameter of D = 500 µm, that is, a superhydrophobicity ratio A* of 19.62%. This work concludes on the optimum biphilic ratio, which is not only effective as a passive method by hindering frosting but also leads to a slush/water free surface after defrosting eased by the Laplace pressure gradient which is imposed by the different biphilic wettability patterns. [ABSTRACT FROM AUTHOR]

Antifrosting surfaces are critical to the efficient and safe operation of infrastructure in cold and humid environments where deposition of frost (porous ice) is thermodynamically inevitable. Such infrastructure can include above-ground power cables and outdoor heat pumps. Here, we introduce a hybrid surface design that passively controls the diffusion of water vapor over a surface to sustain flat frost-free regions for long periods of time. We report more than 150 hours (~1 week) of frost prevention for a single hybrid unit cell, which is three orders of magnitude longer than reported frosting onset for other state-of-the-art techniques. We then demonstrate the potential for large-area frost prevention by scalable tessellation of unit cells and an intrinsic durability to scratches/cracks and physical contamination. [ABSTRACT FROM AUTHOR]

Frost tolerance has evolved many times independently across flowering plants. However, conservation of several frost tolerance mechanisms among distant relatives suggests that apparently independent entries into freezing climates may have been facilitated by repeated modification of existing traits ('precursor traits'). One possible precursor trait for freezing tolerance is drought tolerance, because palaeoclimatic data suggest plants were exposed to drought before frost and several studies have demonstrated shared physiological and genetic responses to drought and frost stress. Here, we combine ecophysiological experiments and comparative analyses to test the hypothesis that drought tolerance acted as a precursor to frost tolerance in cool-season grasses (Pooideae). Contrary to our predictions, we measured the highest levels of frost tolerance in species with the lowest ancestral drought tolerance, indicating that the two stress responses evolved independently in different lineages. We further show that drought tolerance is more evolutionarily labile than frost tolerance. This could limit our ability to reconstruct the order in which drought and frost responses evolved relative to each other. Further research is needed to determine whether our results are unique to Pooideae or general for flowering plants. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) is an excellent tool to solve certain engineering problems connected to material science (such as sulfate swelling, internal degradation due to freezing, and alkali silicate swelling) and to understand specific processes (frost peeling, acid action). Albeit borne and mostly used in the medical domain, CT is increasingly used in the examination of the internal structure of building materials, where degradation processes occur to the detriment of their mechanical performance and durability. This paper presents five engineering problems concerning concrete freezing and thawing, concrete at high temperatures, timber charring, spalling in asbestos‐cement pipes, and deterioration in prestressed concrete pipes due to the corrosion of metallic inserts. In each case, the degradation processes are monitored via CT, something that may be crucial in the renovation and preservation of historical structures. [ABSTRACT FROM AUTHOR]

This study evaluated the impact of night frost incidents on the biochemical, physiological, and reproductive functions of the olive varieties Manzanillo, Coratina, Koroneiki, and Picual. Certain cultivars were more suited to moderate cold night stress than others, based on the changes in the performance of the stressed plants, including vegetative growth, tree yield, fruit physical characteristics, and fruit chemical characteristics. Compared to other tested cultivars, the biochemical responses of the plants in terms of photosynthetic pigments, relative water content (RWC), total phenolic compounds, total flavonoid, and antioxidant enzyme accumulation demonstrated that some cultivars could withstand the applied stress. The conclusion that some cultivars responded differently to cold stress than others was supported by the plant phenology. This research could be a game-changer for farmers. By understanding how olive trees adapt to cold snaps, a common stressor in open fields, they can make informed decisions about breeding and choosing the best cultivars, ultimately leading to more resilient crops. The results showed that all tested olive tree cultivars differ significantly regarding cold stress conditions. Coratina and Koroneiki were the most resistant tested cultivars in terms of biochemical, physiological, and reproductive functions, followed in ascending order by Manzanello and Picual. [ABSTRACT FROM AUTHOR]

In addition to inducing xylem embolism, freeze–thaw events can cause frost fatigue phenomena. Freezing temperature, freezing times, number of freeze–thaw cycles and frost drought can affect the level of freeze–thaw-induced embolism, but it is unknown whether there is an effect on frost fatigue. We assessed whether these frost-related factors changed frost fatigue in the three diffuse-porous species by simulating freeze–thaw treatments under different conditions. We also proposed a new metric, embolism area, in place of embolism resistance, to more accurately quantify the shift of the vulnerability curve after experiencing freeze–thaw-induced embolism and refilling. Frost fatigue caused vulnerability curves of all species to change from S-shaped to double S-shaped or even R-shaped curves. When exposed to a freeze–thaw event, Acer truncatum showed strong resistance to frost fatigue; in contrast, Populus (I-101 × 84 K) and Liriodendron chinense were more vulnerable. Changing freezing temperature and times did not impact the response to frost fatigue in the three species, but a greater number of freeze–thaw cycles and more severe frost drought significantly exacerbated their fatigue degree. Considering that frost fatigue may be a widespread phenomenon among temperate diffuse-porous species, more work is needed in the future to reveal the mechanisms of frost fatigue. [ABSTRACT FROM AUTHOR]

Spring frosts can cause substantial economic and ecological damage, especially when occurring after the growing season has begun and leading to compound climate events, known as false spring (FS) events. This study examines the recurrence, spatial distribution and intensity of FS events in the eastern part of the Baltic Sea region from 1950 to 2022. These events were identified by determining the dates of the last spring frost (LSF) and the start of the growing season (SGS) for each grid cell annually. FS events were distinguished when the LSF date occurred later than the date of the SGS. The sum of growing degree days (tbase = 5 °C), accumulated until the event, and the minimum air temperature (tmin) during the day of the FS event were used to assess the intensity of FS events. Throughout the study period, LSF and SGS dates shifted earlier by an average of 6.3 and 10.6 days, respectively. In 85.9% of the grid cells, the SGS date changed more rapidly than the LSF date. Although the number of FS events increased over the 73 years in most of the study area, no significant changes were observed according to the Mann–Kendall test. However, comparing 1950–1969 and 2003–2022, 85.9% of grid cells saw more FS events, with the largest increase in the eastern part of the study area and southwestern Lithuania. Significant changes were determined in 30% of cells according to the t-test. [ABSTRACT FROM AUTHOR]

Rapidly changing permafrost landscapes are a potential key terrestrial source of greenhouse gases (GHGs) at a global scale, yet, remain poorly characterized regarding GHG origins and environmental controls on emissions. Subsurface ice wedges, commonly found across many permafrost landscapes, harbor GHG‐rich gas bubbles. Analyzing these bubbles aids comprehension of subzero temperature GHG formation in permafrost. The Batagay megaslump, Earth's largest known thaw slump in northern Yakutia, provides an opportunity to study mixing ratios and isotopic compositions of both GHGs and non‐GHG in ice wedge samples from two stratigraphic units: the Upper Ice Complex (UIC) and the Lower Ice Complex (LIC). The Ar/N2/O2 compositions and bubble shapes indicated that the studied ice wedges were likely formed through dry snow and/or hoarfrost compaction, and microbial activity remained active after ice wedge formation. The high CO2 and CH4 mixing ratios and carbon stable isotope values suggested that CO2 and CH4 primarily originated from microbial sources. N2O showed an "exclusive relation" with CH4—meaning that high N2O is observed only when CH4 is low, and vice versa—and N2O mixing ratios vary at different depths. These findings suggest that GHG formation in ice wedges is not solely controlled by physiochemical conditions, but involves a complex interplay between microbial activity and environmental conditions. Our study contributes to a better understanding of the dynamics involved in GHG formation within degrading permafrost landscapes. [ABSTRACT FROM AUTHOR]

Frosting is a common phenomenon of the ASHP under the heating mode in winter, and the outdoor air flow rate flowing through the evaporator of the ASHP was always thought to be a major contributor. In order to validate its contribution, effects of outdoor fan airflow rate on the performance of air source heat pumps (ASHPs) were investigated under the winter heating condition. The experiment was conducted in a laboratory at the standard 2 °C air dry bulb temperature (DB)/ 1 °C air wet bulb temperature (WB) frosting condition, which enabled the analysis of the operating performance, frosting performance, and heating performance of the ASHP unit by changing the airflow rate of the outdoor fan. Results showed that as the airflow rate of the outdoor fan reduced from 100% to 36%, the operating performance decline and the elevated frosting-defrosting loss were observed. Meanwhile, both the frosting rate and the operating efficiency during frosting-defrosting cycles showed an increasing trend then followed by decreasing tendency. The maximum frosting rate and operating efficiency were 0.92 g/m².min and 2.92, respectively, which were observed at 74% airflow rate of the outdoor fan of the ASHP unit. The observation implied the existence of the "minimum frosting suppression airflow rate ". At 36% airflow rate of the outdoor fan of the ASHP unit, however, the performance of the ASHP unit was attenuated greatly, with the frosting-defrosting efficiency loss coefficient of 0.47, the heating capacity and COP reduction by 51.5 and 38.8%, respectively. These findings provided significant references to the optimization of ASHPs performance with variable airflow rate of the outdoor fan under frosting conditions. [ABSTRACT FROM AUTHOR]

The surface of prune fruit has a thick layer of frosting, which is easily damaged and lost during prunes harvest or postharvest handling, and there is no clear information on the effect of prune surface frost on postharvest storage quality. To investigate the effect of fruit frosting on the softening of prune fruits during storage under vibration stress, prunes were divided into three grades according to fruit frosting in this study and were vibrated for 8 h at a frequency of 5 Hz at 4 °C; then, samples were selected once every 8 d. The results showed that the heavy fruit frosting (HFF) group maintained higher hardness (21.47%), L* (20.85%), and total soluble solids (12.79%) levels at the end of storage and inhibited cell wall-modifying enzyme activities (polygalacturonase, pectin methylesterase, glycosidase, β-glucosidase, and cellulase) compared to frosting-less fruit (FF) group. This group also showed improved expression of key cell wall-modification genes (ADPG2, PME31, CESA1, BGAL3, XTH33, BGLU41) as well as chelate-soluble pectin (72.11%), Na2CO3-soluble pectin (42.83%), and cellulose (36.89%) solubilization and maintained lower water-soluble pectin (34.23%). Microscopic observations showed that the fruit frosting could delay the dissolution of pectin components and protect the cell wall structure. In summary, fruit frosting can effectively inhibit fruit softening and maintain fruit quality. [ABSTRACT FROM AUTHOR]

In this paper, the effect of basalt fiber (BF) on the frost resistance of concrete under different curing conditions was investigated, and its frost resistance mechanism was analyzed. Three different curing conditions (normal curing, short-term curing, and seawater curing) were adopted, and concrete with different BF volume contents was designed. Freeze-thaw (FT) tests were carried out using the rapid freezing method to test the frost resistance of basalt fiber reinforced concrete (BFRC). Additionally, the mass loss rate (MLR), relative dynamic modulus of elasticity (RDME) change, and compressive strength reduction of specimens during the freeze-thaw cycles (FTCs) were evaluated. The results show that when the BF content is 0.15%, under normal curing, short-term curing, and seawater curing conditions, the residual compressive strength of BFRC after FTCs was increased by 5.4%, 28.1%, and 30.9%, respectively, compared to plain concrete. By incorporating BF into concrete, the development of microcracks can be effectively retarded, and damage generation during FTCs can be reduced. In addition, the microscopic morphological characteristics and pore structure characteristics of concrete further elucidate the frost resistance mechanism of BFRC from a microscopic perspective. [ABSTRACT FROM AUTHOR]

Riparian corridors often act as low-land climate refugia for temperate tree species in their southern distribution range. A plausible mechanism is the buffering of regional climate extremes by local physiographic and biotic factors. We tested this idea using a 3-year-long microclimate dataset collected along the Ciron river, a refugia for European beech (Fagus sylvatica) in southwestern France. Across the whole network, canopy gap fraction was the main predictor for spatial microclimatic variations, together with two other landscape features (elevation above the river and woodland fraction within a 300m radius). However, within the riparian forest only (canopy gap fraction < 25%, distance to the river < 150m), variations of up to -4°C and + 15% in summertime daily maximum air temperature and minimum relative humidity, respectively, were still found from the plateau to the cooler, moister river banks, only ~ 5-10m below. Elevation above the river was then identified as the main predictor, and explained the marked variations from the plateau to the banks much better than canopy gap fraction. The microclimate measured near the river is as cool but moister than the macroclimate encountered at 700-1000m asl further east in F. sylvatica's main distribution range. Indeed, at all locations, we found that air relative humidity was higher than expected from a temperature-only effect, suggesting that extra moisture is brought by the river. Our results explain well why beech trees in this climate refugium are restricted to the river gorges where microtopographic variations are the strongest and canopy gaps are rare. [ABSTRACT FROM AUTHOR]

This research work presents a comprehensive experimental study of frost heave in a fine-grained material to investigate the effects of top freezing (TF) and bottom freezing (BF) mechanisms with ice lens formation. A novel test device was built to investigate artificial ground freezing (AGF)-related temperature and load boundary conditions. This paper includes 62 frost heave experiments and test observations up to 10 days. The long test duration allows a precise examination of ice lens growth during thermal steady state when the frost line remains largely stable and the ice lens grows. This state corresponds to the holding phase of a practical in situ AGF implementation where the cooling is used to maintain the frozen body thickness. The freezing observations show that BF heaving is larger than TF heaving in most cases. This is caused by the more favorable hydraulic conditions caused by gravitational effects and vertical cracking that occurs during ice lens formation due to suction. This facilitates water accumulation at the ice lens. An applied load reduces the differences between BF and TF conditions beyond a certain value which corresponds to an overburden capable of preventing the formation of the longitudinal cracks. [ABSTRACT FROM AUTHOR]

Low temperature and frost damage in winter pose a major threat to the production of passion fruit in Fujian Province. Determining the suitability regionalization of cultivation is important. This research combined the methods of historical disaster inversion, orchard positioning observations, and geographical displacement experiments to conduct the regionalization research. Fifty-two samples of passion fruit cold and freezing disasters were obtained, and mathematical statistical methods were used to establish frost damage grade indicators of the main varieties of passion fruit based on the daily extreme minimum temperature (Tmin). The frost damage grade index of Passion Fruit No. 1 and No. 3 was divided into four grades: mild, moderate, severe, and most severe. Verifying the disaster samples taken from the literature and the results of artificial climate chamber disaster experiments, the accuracy rate was 81.8%, so the grade index is of practical significance. According to the results of risk regionalization of cold and freezing injury of the main varieties of passion fruit, the regions with no or mild cold and freezing injury were mainly distributed in the coastal areas of Fujian Province, which is thus the region with the lowest risk of cold and freezing injury for planting passion fruit. [ABSTRACT FROM AUTHOR]

To implement the geographical and future climate adaptation of building moisture design for building projects, practitioners need efficient tools, such as precalculated climate indices to assess climate loads. Among them, the Frost Decay Exposure Index (FDEI) describes the risk of freezing damage for clay bricks in facades. Previously, the FDEI has been calculated for 12 locations in Norway using 1961–1990 measurements. The purpose of this study is both updating the FDEI values with new climate data and future scenarios and assessing how such indices may be suitable as a climate adaptation tool in building moisture safety design. The validity of FDEI as an expression of frost decay potential is outside the scope of this study. Historical data from the last normal period as well as future estimated climate data based on 10 different climate models forced by two emission scenarios (representative concentration pathways 4.5 and 8.5) have been analyzed. The results indicate an overall decline in FDEI values on average, due to increased winter temperatures leading to fewer freezing events. Further, the variability between climate models and scenarios necessitates explicit uncertainty evaluations, as single climate model calculations may result in misleading conclusions due to high variability between models. [ABSTRACT FROM AUTHOR]

This study evaluated the impact of night frost incidents on the biochemical, physiological, and reproductive functions of the olive varieties Manzanillo, Coratina, Koroneiki, and Picual. Certain cultivars were more suited to moderate cold night stress than others, based on the changes in the performance of the stressed plants, including vegetative growth, tree yield, fruit physical characteristics, and fruit chemical characteristics. Compared to other tested cultivars, the biochemical responses of the plants in terms of photosynthetic pigments, relative water content (RWC), total phenolic compounds, total flavonoid, and antioxidant enzyme accumulation demonstrated that some cultivars could withstand the applied stress. The conclusion that some cultivars responded differently to cold stress than others was supported by the plant phenology. This research could be a game-changer for farmers. By understanding how olive trees adapt to cold snaps, a common stressor in open fields, they can make informed decisions about breeding and choosing the best cultivars, ultimately leading to more resilient crops. The results showed that all tested olive tree cultivars differ significantly regarding cold stress conditions. Coratina and Koroneiki were the most resistant tested cultivars in terms of biochemical, physiological, and reproductive functions, followed in ascending order by Manzanello and Picual.

Rapid freeze-thaw (F-T) tests were conducted to study the frost resistance of desert sand concrete (DSC) at different stress levels (SL), desert sand replacement rate (DSRR) and the number of F-T cycles. The impact of the SL, DSRR, and number of F-T cycles on the mass loss rate, ultrasonic wave velocity, and stress-strain curve of DSC was investigated through uniaxial compression tests. Scanning electron microscope (SEM) was used to examine the microstructure of DSC. The constitutive relationship was established considering the influence of the SL and number of F-T cycles. The results indicated that the frost resistance and uniaxial compressive mechanical properties of DSC could be effectively enhanced when desert sand was added at 40%. The peak strain initially decreased and then increased as the DSRR increased. In contrast, the peak stress first increased and reached a maximum value as the DSRR increasing to 40%, followed by a gradual decrease. The F-T cycles gradually deteriorated the macroscopic properties of DSC. The proposed constitutive model of DSC was established by combining the two classical models as the ascending and descending sections, respectively. The model prediction results matched well with the experimental results, which can provide a theoretical basis for the engineering application of DSC under F-T cycles and loading environments. [ABSTRACT FROM AUTHOR]

This study presents a simulation model to predict the nozzle surface freezing phenomenon that causes delays in refueling hydrogen vehicles. Nozzle surface freezing is known to occur when vehicles are refueled consecutively. The developed model allows consecutive refueling of vehicles and incorporates the actual nozzle material to accurately calculate the nozzle surface temperature. The simulation results indicate that, under the applied boundary conditions, the nozzle surface temperature reaches freezing conditions during the third refueling cycle, suggesting the potential suitability of using hot air or nitrogen after the second refueling. Future applications include exploring different boundary conditions in the developed hydrogen refueling model to simulate internal refueling pressure, temperature and nozzle icing conditions. This optimisation could facilitate decision making for the implementation of hot air or nitrogen, which could potentially reduce refueling time and contribute to cost savings at hydrogen refueling stations, depending on specific environmental conditions. • Charging hydrogen vehicles consecutively results in icing, causing delays. • A simulation model is proposed for consecutive vehicle charging, incorporating the nozzle where icing occurs. • Icing occurs during charging of three hydrogen vehicles consecutively (with a waiting time of 90 s). • After the second refueling, purging with heating air or similar means is considered appropriate. [ABSTRACT FROM AUTHOR]

Seeking to promote the earliness traits in apples (Malus × domestica Borkh.), this study evaluated 246 half-sib descendants of their mature trees for pheno-morphology, pomological, and sensory attributes. From a productivity criterion, the gene pool performance ranked in 12 resistance and susceptibility classes to spring frost. The two selected groups comprised five and 23 descendants, assigned by high and moderate tolerance in 2019. In the following season, assessing 246 progenies for bloom intensity led to the selection of 80 outstanding hybrids. The earliness traits showed a high promotion of the appearance of new classes of earliness. The ripening time distribution of the bearing progenies consisted of six categories, namely, four extra-early (June 5 to 17), 18 far-early (June 22 to 30), 22 very early (July 2 to 9), 21 very early-early (July 11), nine early plus to control (July 19), and six progenies (July 25). Subsequent pomological and sensory analyses led to the choice of 18 progenies for high fruit set, well-formed fruits, different colors, and superior organoleptic qualities. The results authenticated the efficiency of breeding methods, supported by heritability and morphological markers to predict the earliness traits. [ABSTRACT FROM AUTHOR]

Background and Aims Reduced snow cover and increased air temperature variability are predicted to expose overwintering herbaceous plants to more severe freezing in some northern temperate regions. Legumes are a key functional group that may exhibit lower freezing tolerance than other species in these regions, but this trend has been observed only for non-native legumes. Our aim was to confirm if this trend is restricted to non-native legumes or whether native legumes in these regions also exhibit low freezing tolerance. Methods First, we transplanted legumes (five non-native species and four native species) into either an old field (non-native) or a prairie (native) and used snow removal to expose the plots to increased soil freezing. Second, we grew plants in mesocosms (old field) and pots (prairie species) and exposed them in controlled environment chambers to a range of freezing treatments (control, 0, −5 or −10 °C) in winter or spring. We assessed freezing responses by comparing differences in biomass, cover and nodulation between freezing (or snow removal) treatments and controls. Key Results Among legume species, lower freezing tolerance was positively correlated with a lower proportion of nodulated plants and active nodules, and under controlled conditions, freezing-induced reductions in above-ground biomass were lower on average in native legumes than in non-native legumes. Nevertheless, both non-native and native legumes (except Desmodium canadense) exhibited greater reductions in biomass in response to increased freezing than their non-leguminous neighbours, both in controlled environments and in the field. Conclusions These results demonstrate that both native and non-native legumes exhibit low freezing tolerance relative to other herbaceous species in northern temperate plant communities. By reducing legume biomass and nodulation, increased soil freezing could reduce nitrogen inputs into these systems. [ABSTRACT FROM AUTHOR]

This study aims to design an early warning system based on machine learning for short-term prediction of nocturnal frosts in Kurdistan Province in the west of Iran. Four models of artificial neural network (ANN), support vector machine (SVM), adaptive neuro-fuzzy inference system (ANFIS), and multiple linear regression were used to achieve this main goal. Hourly data of six variables of dry-bulb temperature, wet-bulb temperature, cloud cover, relative humidity, and wind speed and direction were selected as the inputs of these four models at 18:30 local time, and according to them, nocturnal temperatures were predicted for 21:30, 00:30, 03:30, and 06:30 local time. Comparing the outputs of these four models with observational data, all models predicted nocturnal temperatures both in the early hours (21:30 and 00:30 local time) and in the late hours of the night (03:30 and 06:30 local time) the same or less than the observational temperatures. Considering the different performance criteria of the models, such as mean absolute errors (MAE), mean squares errors (MSE), and root-mean-squares errors (RMSE), ANN with Posline transfer function, and Trainlm training function, has less error and better performance in predicting nocturnal temperatures compared to other models. When the main goal is predicting the temperature extremes, especially frost, it is concluded that ANN did not perform very well compared to other models. In addition, ANFIS and SVM models have a better performance in this area than other models. Finally, an early warning system for nocturnal frost was designed for Kurdistan Province in the west of Iran using these four models, and its ability was tested to make short-term nocturnal frost predictions. The results show that this system is suitable for the short-term prediction of nocturnal frosts. [ABSTRACT FROM AUTHOR]

(1) Background: Spring frost damage is a common phenomenon that occurs in Southern Chile that considerably affects vine productivity and grape quality. (2) Methods: A field trial was conducted in order to study vine phenology and berry physicochemical parameters in Chardonnay, Sauvignon Blanc and Pinot Noir ungrafted and grafted (onto 101-14 Mgt rootstock) grapevines after a spring frost. This event killed the totality of primary bud shoots when the vines reached the phenological stage of unfolded leaves. (3) Results: From budburst, to flowering of secondary bud shoots, ungrafted Sauvignon Blanc grapevines presented an advanced phenology, whereas 101-14 Mgt rootstock tended to advance the maturity of Pinot Noir grapevines from flowering to ripening of berries. At harvest, berries from secondary buds of vines grafted onto 101-14 Mgt rootstock showed higher soluble solids than the ones from ungrafted Chardonnay and Sauvignon Blanc vines. High total phenolic content was found in berries from secondary buds of the grafted vines, compared to the ones from the ungrafted vines. Berry soluble solids variability tended to statistically decrease toward harvest in the studied plant materials, and the maximum coefficient of variation for soluble solids, berry weight, berry firmness and berry size reached 9.5%, 25.9%, 18.6% and 8.9%, respectively. (4) Conclusions: These preliminary results may be interesting for the Southern Chilean viticulturists since it seems that 101-14 Mgt rootstock could affect phenology and grape berry maturity of grapevines established in the Cautín Valley after spring frost damage. [ABSTRACT FROM AUTHOR]

Cryogenic valves play a crucial role in the production and transportation of liquefied natural gas (LNG), and are primarily responsible for efficiently controlling the inflow and outflow of LNG and regulating pressure. However, due to their operation in low-temperature and high-humidity environments, crucial components such as drip trays are susceptible to frosting, which may lead to LNG leakage, thereby causing severe safety incidents. In this study, the user-defined function (UDF) is employed to redevelop Fluent, which integrates the frost growth model with the Eulerian multiphase flow model, to conduct a quantitative analysis of frosting on drip trays of cryogenic valves. The effects of environmental parameters, such as wind speed, ambient temperature, air humidity, and cold surface temperature on the growth of the frost layer were analyzed. This study reveals a limiting wind speed between 1 m/s and 2 m/s. Upon reaching this limit speed, the growth of the frost layer reaches its maximum, and further increases in the wind speed have no significant effect on the growth of the frost layer. Furthermore, the influence of the change in the flow field on droplet impingement and freezing during the growth of the frost layer is considered through the coupling method of the kinematic characteristics of water droplets and the collection coefficient of water droplets. This study identifies the influence of different parameters on the droplet impact efficiency, leading to the modification of the frost layer on the drip tray. [ABSTRACT FROM AUTHOR]

Introduction: Olive cultivation, like other evergreen fruit cropsworldwide, is limited by the occurrence of frost episodes in different times of the year, mainly in winter or early spring. Some contradictory results are reported about cultivars' response to frost, which depends on the physiological stage of the tissues (acclimated or not acclimated) when the cold or frost episode occurs. This work aimed to implement a user-friendly and reliable lab method for discerning frost tolerance. Methods: Our methodology considered both detached leaves and potted plantlets. The optimal temperature at which damage differentiated between cultivars was evaluated, as well as the time of exposure to cold and the recovery time for the correct evaluation of the symptoms. Furthermore, a comparative analysis of damage on both young and mature leaves was conducted. To validate the efficacy of the methodology, assessments were conducted on the cultivars 'Arbequina' (tolerant), 'Picual' (moderately tolerant), and 'Frantoio' (susceptible) under acclimated and non-acclimated conditions. Results and discussion: The results indicated that, when detached leaves were used for frost evaluation, a temperature of -10°C ± 1°C for 30 min and a recovery time at 26°C for 24-48 h after exposure to cold are enough to induce damages on the leaves and discriminate between cultivar susceptibility. Under these conditions, a precise assessment of symptoms can be made, facilitating the categorization of frost tolerance level in various olive cultivars. Notably, no significant differences were observed between young and mature leaves during the evaluation process. On the other hand, the critical temperature to assess damages on potted plantlets was determined to be -7°C ± 1°C. In addition, it was observed that acclimated plants exhibited fewer symptoms compared to non-acclimated ones, with 'Frantoio' being the most affected alongside 'Picual' and 'Arbequina'. Conclusion: The implemented methodology will allow the assessment of frost tolerance in several olive cultivars within a short timeframe, and it is proven to be user-friendly and reliable. [ABSTRACT FROM AUTHOR]

Background: Currently, there is no scientific evidence regarding pain in the anesthetic block of the first toe according to the method of application. However, clinical evidence has highlighted the use of the carpule due to the low pain it causes during the administration of the anesthetic. Most studies on anesthesia and pain, especially using the carpule and distraction methods, belong to the field of dentistry. Objective: To compare the pain and effectiveness between the anesthetic block of the first toe using a carpule and syringe with Frost's H technique and the modified Frost's H technique. Method: A total of 564 subjects were selected and divided into four groups. Subjects were subjected to experimental conditions (randomization through the Random Allocation Software program 2.0), and divided into group 1 = 138 subjects, corresponding to the block with syringe and Frost's H, group 2 = 141 subjects, corresponding to the syringe group and modified Frost's H, group 3 = 141 subjects, corresponding to the carpule group and modified Frost's H, and group 4 = 144 subjects, corresponding to the carpule group and Frost's H. The same researcher generated the random allocation sequence, enrolled the participants, and assigned them to the interventions. Each subject was unaware of the anesthetic procedure assigned by the researcher. Outcome parameters were pain after anesthetic infiltration and its effectiveness. Results: The anesthetic block with carpule showed a lower pain score compared to the anesthetic block with syringe (2.8 vs. 5.3; p < 0.001). However, when analyzing effectiveness, a higher efficacy rate was obtained in the anesthetic blocks performed using the modified Frost's H technique (97.5% vs. 88.1%; p < 0.001). Conclusions: The anesthetic block with carpule and the modified Frost's H technique is less painful and more effective than the traditional anesthetic block. [ABSTRACT FROM AUTHOR]

Permeable concrete has the characteristics of breathability, permeability, and high heat dissipation. To improve its mechanical and frost resistance properties, this study optimized the preparation and performance of permeable concrete by adding materials to improve its performance. The performance analysis validate that epoxy resin owns a filling effect on the pores of permeable concrete. The internal curing agent, high water absorbent resin, has a good water absorption effect. The synergistic effect of these two increases the density and compressive strength of permeable concrete. When the two contents are 0.5%, the maximum compressive strength of modified permeable concrete at 7 and 28 days was 15.62 and 17.97 MPa, respectively. Under the action of freeze-thaw cycles, its mass loss rate show an upward trend By comparison, epoxy resin and high water absorbent resin are beneficial for improving the frost resistance of permeable concrete. The minimum value of relative dynamic modulus of elasticity remains stable at over 80%, and the loss rate of dynamic modulus of elasticity is all below 0.4. However, the influence of epoxy resin and SAP on the mass loss rate is relatively small, and the mass loss of all experimental groups is controlled below 2.5%. The binomial Fourier function model is the best predictive model for permeable concrete under freeze-thaw cycles. This study has positive significance for improving the performance of permeable concrete and maintaining the sustainable development of ecological cities. [ABSTRACT FROM AUTHOR]

Frost is one of the most frequent, intense, and influential agrometeorological disasters that occurs frequently in Northeast China. The study of the spatiotemporal changes of ground frost is of great significance for farmers and policymakers in Northeast China, as it can inform decisions related to crop selection, planting schedules, and the development of regional climate adaptation plans. In this study, the spatiotemporal changes of frost indices (last spring frost (LSF), first fall frost (FFF), and frost-free period (FFP)) in Northeast China were analyzed from 1961 to 2020. Then, we investigated the mutation characteristics of the frost indices and their correlation with geographical factors. The results revealed that (1) the LSF, FFF, and FFP in Northeast China were concentrated at 120–140 DOY, 260–280 DOY, and 110–170 days, respectively. The spatial distribution of frost indices exhibited significant spatial heterogeneity. (2) The LSF, FFF, and FFP showed significant trends of advancement, delay, and extension, with trends of −1.94 days/10 a, 1.72 days/10 a, and 4.21 days/10 a, respectively. (3) More than 80% of the LSF, FFF, and FFP of the sites showed trends of advancement, delay, and extension, with greater variability in the central part of Heilongjiang Province. (4) The FFF and FFP experienced an abrupt change in the late 1990s. (5) The correlation between latitude and LSF, FFF, and FFP was the strongest, with correlation coefficients of 0.77, −0.79, and −0.78, respectively. This study provides a comprehensive understanding of the changing characteristics of ground frost indices that impact agricultural production in Northeast China against the backdrop of climate change. The findings hold significant scientific value in guiding the adaptation of agricultural production layouts in Northeast China to the evolving climatic conditions. [ABSTRACT FROM AUTHOR]

A symposium on Samantha Frost's Lessons from a Materialist Thinker: Hobbesian Reflections on Ethics and Politics offers an opportunity to revisit one of the most original contributions to Hobbes scholarship in the last few decades. The book's originality resides not only in recuperating Hobbes's materialist metaphysics for contemporary ethics and politics, but in making Hobbes's take on matter inform novel conceptual approaches to social and non-social reality, such as new materialism – a philosophical school that conceives matter as vibrant and agentic, rather than inert. [ABSTRACT FROM AUTHOR]

In cold areas, the steel fiber reinforced rubber concrete (SFRRC) pavement is exposed to natural environment and experiences varying degrees of damage from freezing and thawing. This can have a serious impact on the normal usage and safe operation of the pavement structure. This research examines the impact of varying rubber concentrations on multiple variables, such as the rate of mass reduction, relative dynamic modulus of elasticity, compressive strength, and thickness of the damage layer (Hf) during freeze–thaw (F-T) durability testing conducted on SFRRC. Furthermore, an analysis is conducted to determine the degradation pattern exhibited by SFRRC. The internal structure evolution and pore structure characteristics of SFRRC were examined using scanning electron microscopy and mercury intrusion porosimetry techniques, which revealed the underlying damage mechanism in SFRRC during F-T cycles. The results suggest that the addition of an appropriate amount of rubber can effectively enhance the frost resistance of SFRRC in water. A gradual improvement in the frost resistance of SFRRC is observed when increasing the rubber content from 0 to 10%. The optimal frost resistance is observed in SFRRC with 10% rubber content. However, when the rubber content reaches 15%, SFRRC exhibits significant degradation and lower level of resistance to freezing compared to SFRRC without rubber. Microcracks form within SFRRC due to the freezing–thawing forces experienced during the experiment, resulting in the development of a damage layer that extends from the surface to the interior. The compressive strength of the damaged layer significantly decreases as Hf increases. The addition of appropriate rubber in SFRRC improves its pore structure, leading to an increased proportion of harmless or less harmful pores and a reduction in average pore size, thereby significantly enhancing its frost resistance. [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]

To prevent frost damage in fruit trees, growers employ passive and active methods, and one of these second methods is the use of biostimulant compounds against abiotic stress. In this study, two trials were conducted to evaluate the effectiveness of a multi-attribute approach biostimulant—containing α-tocopherol, boron, and glycols, in peach ('UFO-4' cultivar) and almond ('Vairo' cultivar) trees. In a first trial, one-year-old shoots with flowers were collected after 24 h, 48 h, and 96 h of the biostimulant applications. Two different application rates of the product (1000 and 2000 cc ha−1) were tested and compared to an untreated control. In a second trial, one-year-old shoots with fruitlets were collected after 24 h of the biostimulant applications. In this case, only an application rate (2000 cc ha−1) was tested. In the two trials, the collected one-year-old shoots were subjected to different frost temperatures using a controlled environment chamber. The damage level was assessed by a morphological analysis of the flowers and fruitlets 96 h after each frost cycle simulation. The lethal temperatures (LT10, LT50, and LT90) of each treatment were calculated by probit analysis. The product applied 24 h and 48 h before the frost simulations significantly decreased the LT10 and LT50 in 1.5 °C in peach flowers, and 2.5 °C in almond flowers (a temperature reduction of 50% and 75%, respectively). These results were more consistent when the application volume was 2000 cc ha−1, instead of 1000 cc ha−1. Significant differences between treated and non-treated fruitlets were observed only in almond fruitlets, with LT10 and LT50 being 0.5 °C lower in treated fruitlets (20% reduction). In conclusion, the multi-attribute approach biostimulant applied 24 or 48 h before the frost reduced the mortality of peach and almond flowers, but its effectiveness to protect fruitlets after bloom was inconsistent. [ABSTRACT FROM AUTHOR]

This paper compares the performance of a vertical-finned microchannel heat exchanger (VMHX) and a 2-row fin-tube heat exchanger (FTHX) under wet and frosting conditions. The VMHX features vertically oriented fins with an extension at the windward side and parallel microchannel tubes, allowing for efficient water drainage and better performance than conventional microchannel heat exchangers with parallel serpentine fins. However, the performance of the VMHX has not been sufficiently compared to that of FTHX. After conducting experiments under specific operating conditions, the VMHX exhibits better water drainage performance than the FTHX at higher inlet air velocities, higher maximum heat flow, and time-integrating heat flow under certain operating conditions. Although the heating time is relatively shorter than the 2-row FTHX, these results suggest that the VMHX may be a more suitable option for applications requiring efficient water drainage and heat transfer. Additionally, the operating conditions significantly affect the heat exchanger's performance. The performance of VMHX is analyzed under different inlet air velocities, inlet air temperatures, and evaporation temperatures. The results indicate that frost itself had no effect on the heat exchanger performance and that the decrease of the inlet air flow rate was the main factor that decreased the heat exchanger performance. Overall, the results of this study provide valuable insights into the performance of VMHX and FTHX under wet and frosting conditions and the impact of various operating parameters on VMHX performance. These findings can inform the development of more efficient and reliable heat exchangers for various applications. [ABSTRACT FROM AUTHOR]

Heat shock proteins (HSPs) are mainly known to play important roles in plants against high-temperature (HT) stress. Their main function is to act as molecular chaperones for other proteins. It has also been proven that HSPs have a protective effect during other environmental stresses including low temperature (LT). To the best of our knowledge, the expression and role of HSPs in plants that have been exposed to LT have not yet been sufficiently reviewed. The aims of this minireview were (1) to briefly describe the origin, classification, structure, localisation and functions of HSPs, (2) to present the current knowledge about the changes in the accumulation of HSPs in plants that have been exposed to LT, (3) to discuss some of the molecular changes that occur during LT action and that lead to the accumulation of HSPs in plants and (4) to discuss the potential role of HSPs in acquiring tolerance to cold and frost in plants including economically important crop species. Some directions of research on the role of HSPs in plants growing in LT conditions are proposed. [ABSTRACT FROM AUTHOR]

Improvement of hydrophysical properties and corrosion resistance of self-compacting concrete to the effects of alternate freezing–thawing and aggressive soils of Southern and Central Kazakhstan is of interest to a wide range of researchers from the side of practical application of the obtained results in construction practice. It is proposed to form a spatially reinforced fine crystalline structure of a cement matrix with the maximum dense packing by using a complex modifier (hyperplasticizer + polymer + microsilica + fibro fibers) in the composition of self-compacting concretes (SCCs). The introduction of the calculated amount of the above additives increases the operational reliability of the current SCC compositions, increasing the water resistance to W16, frost resistance to F = 500, increasing the compressive strength by 20%, and reducing the mass loss of samples during corrosion leaching to 50%. It has been experimentally established that the proposed addition of the complex modifier (hyperplasticizer + polymer + microsilica + fibro fibers) to the SCC composition allows obtaining self-compacting concrete of high quality with improved performance characteristics (compressive strength, water resistance, frost resistance, and corrosion resistance). Studies have shown that the complex modifier-modified SCC compositions have a high degree of resistance in aggressive environments and leaching corrosion. Based on the results of the conducted tests, it is possible to recommend the obtained SCC compositions for the production of building products working in the zone of alternating freezing–thawing and aggressive soils. [ABSTRACT FROM AUTHOR]

Agro-meteorological disasters are a significant cause of crop yield reduction. Northeast China is a major base for commodity grain production and is also highly sensitive to climate change. Early frost is one of the most significant meteorological disasters in Northeast China. The typical weather system serves as the primary meteorological cause of the occurrence of early frost. The Northeast Cold Vortex is a cyclonic system of certain intensity located in Northeast China, which has the potential to induce severe weather conditions such as extreme low temperatures and intense convection. Despite extensive research on the first occurrence of frost in Northeast China, the evolutionary characteristics under the combined influence of climate change and the Northeast Cold Vortex remain unclear. This limitation hinders the development of effective monitoring and early warning systems for early frost, as well as the formulation of disaster prevention and mitigation plans for crop production. Therefore, this study aims to objectively document the occurrence of early frost in maize crops in Northeast China from 1961 to 2021 under the influence of the Northeast Cold Vortex. It seeks to unveil the climatic characteristics and evolutionary patterns of early frost events in maize crops within this region, considering the impact of the Northeast Cold Vortex. Additionally, it endeavors to analyze the factors contributing to varying degrees of early frost caused by the Northeast Cold Vortex. The results showed that the occurrence of both early frost and frost influenced by the Northeast Cold Vortex exhibited a declining trend. Furthermore, there was also a decreasing proportion of initial frost attributed to the Northeast Cold Vortex, with a decline rate of 2% per decade, indicating a diminishing dominance of initial frost caused by this weather system. The onset date for the early frost under the influence of the Northeast Cold Vortex progressively advanced from southeast to northwest, occurring 4 days earlier than during the period from 1961 to 1990 between 1991 and 2021. While early frost displayed an increasing spatial distribution from southeast to northwest, it is noteworthy that the majority concentration of the Northeast Cold Vortex was observed in central regions, highlighting its predominant role in causing early frost in Northeast China. [ABSTRACT FROM AUTHOR]

The permafrost in Northeast China is experiencing rapid degradation due to the influence of climate change and human activities, profoundly impacting the local ecological environment and engineering construction. Understanding the spatiotemporal dynamics of long-term permafrost in this region is crucial; however, systematic research on this topic remains scarce. This study combines meteorological station data, MODIS land surface temperature (LST) datasets, and borehole locations to apply the surface frost number (SFn) model. This approach enables the simulation and estimation of the spatial distribution and changes in the area of the surface frost number without vegetation effects (SFnv) and permafrost temperature (PT) in Northeast China from 1971 to 2020. The area of the SFnv > 0.49 within the permafrost region decreased substantially from approximately 44.353 × 104 km2 to 19.909 × 104 km2 between 1971 and 2020, with a notable change in 1988. The area of permafrost calculated using PT < 0 was slightly smaller, declining from 39.388 × 104 km2 to 29.852 × 104 km2. There was also a significant increase in the area with PT ranging from −1 °C to 0 °C, indicating a decline in permafrost stability. Approximately 10.926 × 104 km2 of stable permafrost has been transformed into semi-stable and unstable permafrost. Moreover, from 1982 to 2020, the NDVI was negatively correlated with the area of stable permafrost and positively correlated with the area of transitional or unstable permafrost. Vegetation cover decreased as transitional or unstable permafrost degraded. These findings provide valuable information for permafrost research and engineering development in cold regions, as well as for future planning and adaptation strategies. [ABSTRACT FROM AUTHOR]

The effectiveness of apricot cultivation is greatly threatened by frost damage to flower buds during the dormancy period. One of the most important aspects of the evaluation of cultivars is therefore the determination of their frost tolerance. In this paper, the frost hardiness of flower buds of 16 apricot cultivars was investigated in three dormancy periods, applying a standardised artificial freezing test protocol and determining LT50 values. The results showed that both the genotypes and the yearly climatic conditions had a significant effect on frost tolerance. A genotype generally determines the potential maximum of its frost tolerance ('Sweet Red' and 'Primaya' were very sensitive to frost every year, while 'Harlayne' and 'Rózskajszi C.1406' could be considered as frost hardy). Flower buds can reach different levels of frost resistance each year depending on the temperature conditions during the hardening and dehardening periods. From the point of view of yield security, it is essential when planning an orchard, to take into account and harmonise the frost hardiness of the cultivars selected and the growing site conditions. Therefore, it is very important to have adequate information about the frost hardiness of different apricot cultivars, which should be included in cultivar descriptions. This paper is intended to contribute to this goal. [ABSTRACT FROM AUTHOR]

Extreme cold events can have several consequences in different sectors, including human health, infrastructure, agriculture, and the economy. The frost events that affect central and northeastern Argentina are associated with stationary Rossby waves triggered by tropical heat sources and convection, which result in intense polar air advection. However, the processes responsible for these cold events include complex interactions between these wave trains and mechanisms at different atmospheric scales, such as the Madden–Julian Oscillation (MJO), which can alter the temperature patterns. This study investigates the impacts of the MJO on air temperature and associated circulation in years with extreme occurrence frequency of cold events in central southern South America during the winter. The results showed that the MJO convection can enhance or weaken the temperature anomalies during winters with a maximum and minimum frequency of generalized frosts (GF) occurrence due to Rossby wave train propagation triggered in the tropical region. Moreover, the effect on the anomaly patterns in these events depends on the MJO phase. Our analysis shows that individual MJO phases can modulate the temperature anomalies even in an unfavorable basic state (as in winters with an extreme frequency of GF and emphasizes the importance of considering the MJO in the predictions of the temperature anomalies associated with GF over southeastern South America. [ABSTRACT FROM AUTHOR]

Surface damage of concrete induced by freezing and thawing (F-T) cycles in cold regions is characterised by peeling and pits as features of the damaged concrete surface, which needs characterising before repairing. A spot laser ranging system was established with high accuracy, and its ability to detect concrete surface features was evaluated. A 50 mm × 50 mm zone on a surface of C30 concrete specimen, with 2550 measurement points in it, was defined to obtain vertical displacements and other parameters. Mean vertical displacement of measurement points increase with F-T cycles. Effectiveness of the proposed method to characterise concrete surface damage is verified by significant regression relationship between mean vertical displacement and mass of scaling substances per unit area. Analysis of other parameters reveals that frost pit's depth increases within initial 8 F-T cycles, while its cross-sectional area increases in the subsequent 12 F-T cycles. However, in the final 8 F-T cycles, frost pit's cross-sectional area increases more significantly. Thus, the system is well performed in detecting frost pits on concrete surface non-destructively. The insights prolongate application of laser technology, which provides a new perspective to study the evolution of surface damage of concrete subjected to F-T cycles. [ABSTRACT FROM AUTHOR]

Frozen storage of food products is widely accepted not only in the industry but also by households. Frost formation during long-term storage is recognized as a phenomenon that causes changes in product characteristics and quality losses. However, quantitative prediction and control of frost formation remains a challenge. In this study, a mathematical model was developed to predict frost formation inside frozen food products (i.e., frozen minced meat packed in a polyvinylidene chloride (PVDC) film) under fluctuating temperature conditions in a domestic refrigerator. The proposed model is based on heat transfer and energy balance equations, and the amount of frost formation is estimated from the heat generated by condensation. The heat transfer coefficients were experimentally obtained and applied to the developed model. The interactions between the amplitude and frequency of temperature fluctuations and the corresponding amount of frost formation were visualized using contour plots. Both the amplitude and frequency were found to increase frost formation. For the range of fluctuations tested (temperature amplitudes of 0.5–2.5 K and cooling rates of 0.0125–0.2 K/min when connected to the compressor), the simulation predicted that the amount of frost in the packages varied up to approximately 4.5 times (0.48–2.18 g/month for packages containing 300 g of minced meat) depending on the different temperature fluctuation settings. [ABSTRACT FROM AUTHOR]

The article focuses on the discovery of a "Frozen Charlotte" doll in Frost Town, New York, shedding light on family life in this 19th-century logging village. Topics include the history of Frost Town as a logging settlement; the cultural significance and origins of Frozen Charlotte dolls; and the insight this artifact provides into the childhood experiences of the village's residents.

Frost damage on the concrete surface might be aggravated when freezing occurs in the presence of a salt solution, like sea water or de-icing salt. A possible mechanism behind this combination of frost and salt is discussed. When freezing takes place in pure water, ice formed at the surface will block inflow of water to the concrete, but it will cause drying of the concrete. When freezing occurs in salt solution, unfrozen water (brine) can enter the concrete surface and make the concrete completely saturated. When pore water freezes, it exerts pressure. The effect of air-entrainment is favourable since it reduces the stresses. A calculation is made of the air requirement for concrete with w/c-ratio 0.45. [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. [ABSTRACT FROM AUTHOR]

Climatic warming has advanced the spring phenology of plants and disrupted the alignment of phenology with weather patterns. Such misalignments can cause problems as extreme weather events become more frequent and thus impact the survival, growth and reproduction of plants. To prevent freezing within their cells during the growing season, plants adopt a supercooling strategy. However, the weather event severity and seasonal timing may impact the plant's recovery after a freezing event. We conducted experiments to investigate how extreme freezing events of four different severities impacted the supercooling points and senescence of two dominant alpine plant species, Potentilla saundersiana (mid-summer flowering) and Gentiana parvula (late-summer flowering) on the Qinghai-Tibet Plateau (QTP). We also explored how the phenological stage impacted P. saundersiana 's response to freezing events. We found that both species exhibited supercooling upon exposed to frost damage. However, the average supercooling point for P. saundersiana was −6.9°C and was influenced by minimum temperature, duration and phenological stage. Whereas, the average supercooling point for G. parvula was −4.8°C, and neither minimum temperature nor duration had an effect on the supercooling point. In addition, the minimum temperature treatment of −10°C caused death in both plants when held constant for 4 h. Our study provides the first experimental dataset exploring the supercooling points of alpine plants on the QTP. Given the increasing probability of alpine plants encounters frost events, these results are of great significance for understanding the growth and survival strategies of alpine plants to cope with the adverse effects of extreme climate. [ABSTRACT FROM AUTHOR]

Frost is damaging to plants when air temperature drops below their tolerance threshold. The set of mechanisms used by cold-tolerant plants to withstand freezing is called “hardening” and typically take place in autumn to protect against winter damage. The recent incorporation of a hardening scheme in the demographic vegetation model FATES opens up the possibility to investigate frost mortality to vegetation. Previously, the hardening scheme was used to improve hydraulic processes in cold-tolerant plants. In this study, we expand upon the existing hardening scheme by implementing hardiness-dependent frost mortality into CLM5.0-FATES to study the impacts of frost on vegetation in temperate and boreal sites from 1950 to 2015. Our results show that the original freezing mortality approach of FATES, where each plant type had a fixed freezing tolerance threshold—an approach common to many other dynamic vegetation models, was restricted to predicting plant type distribution. The main results emerging from the new scheme are a high autumn and spring frost mortality, especially at colder sites, and increasing mid-winter frost mortality due to global warming, especially at warmer sites. We demonstrate that the new frost scheme is a major step forward in dynamically representing vegetation in ESMs by for the first time including a level of frost tolerance that is responding to the environment and includes some level of cost (implicitly) and benefit. By linking hardening and frost mortality in a land surface model, we open new ways to explore the impact of frost events in the context of global warming.

‘Marquette’ is a cold-hardy hybrid grape cultivar that has received increased attention for its use in wine production in the upper midwestern and northeastern United States since it was released in 2006. However, ‘Marquette’ is an early budburst cultivar susceptible to spring freeze damage. We examined the influence of high wire bilateral flat cane (HWC) and four-arm Kniffin (4AK) training systems on young ‘Marquette’ performance during a year with spring freeze damage (2017) and the subsequent season without frost events (2018). In 2017, there were two consecutive spring frost events at the experimental site approximately 2 weeks after the vines reached 50% budburst, which damaged more than 70% of the shoots. The percentage of freeze-damaged shoots and the severity of freeze damage to green tissues did not differ between training systems, but 4AK vines had higher yield at harvest (5.16 kg/vine or 3.12 tons/acre) than HWC vines (3.45 kg/vine or 2.10 tons/acre) because of the greater number of buds retained at winter pruning. There was no freeze damage close to budburst in 2018, and the yield of 4AK vines was still higher (11.74 kg/vine or 7.08 tons/acre) than that of HWC vines (8.20 kg/vine or 4.98 tons/acre). In 2018, the Ravaz index (yield-to-pruning weight) values were lower for HWC vines (3.41) than for 4AK vines (5.39), but the training system did not consistently affect fruit composition in either vintage. Within the 4AK system, shoots that emerged from the lower cane had more freeze damage than those of the upper cane and produced lower crop yield and fruit with lower soluble sugars in both vintages. Our results suggest that ‘Marquette’ vines can be grown on a training system with high cropping potential, such as a divided canopy system or a single canopy, with a higher number of buds and shoots than that of our study. Among divided canopy systems, 4AK might not be the best option for vigorous ‘Marquette’ vines because, in addition to greater susceptibility to freeze damage, the lower cane of 4AK was highly shaded by the upper highly vegetative canopy, which might have caused its lower productivity and soluble sugars at harvest compared with those of the upper cane.

Fruit tree frost, an agricultural meteorological disaster primarily occurring in spring, severely impacts the growth and development of trees and fruit set. Therefore, exploring the temperature change rules of fruit trees during frost events is of considerable importance. This study used a T40 unmanned aerial vehicle (UAV) as the test vehicle based on the air disturbance frost prevention principle. The airflow field change pattern of the UAV was explored using the computational fluid dynamics simulation method, and the reliability of the multi-rotor UAV in frost prevention was verified using field tests. Setting the UAV height at 6.0 m above the ground and the rotor speed at 1000 r min−1, it was found that under the conditions of the inverse temperature phenomenon, the temperatures of different altitude layers will eventually converge to a stable value when the UAV down-rotating airflow is disturbed, which could be completed rapidly within 20 s. The results of the field test also showed that when the fruit trees reached the critical temperature of frost at the flowering stage, UAV intervention could have a substantial effect on the warming of the near-surface layers, whose warming amplitude was in the range of 2.5 °C–3 °C. This study provides a reliable method for mitigating frost, which serves as an important theoretical and guiding basis for improving agricultural frost disasters in China. • A multi-rotor UAV is used to test frost protection performance on fruit trees. • The temperature field characterizations are obtained. • The anti-frost effectiveness of UAV intervention is confirmed. [ABSTRACT FROM AUTHOR]