Ice Crystals Research Articles

Numerical Investigation of Wind Turbine Airfoil Icing and Its Influencing Factors under Mixed-Phase Conditions

Icing is a popular research area in wind energy, and the icing problem of the supercooled droplet–ice crystal mixed-phase condition is one of the new challenges. A numerical method for analyzing the icing characteristics of wind turbine airfoil under mixed-phase conditions is presented. The control equations for the dynamics of supercooled droplets and ice crystals are formulated using the Lagrangian method. Equations for the conservation of mass and energy during the icing process involving supercooled droplets and ice crystals are constructed. The impact of erosion phenomena on the mixed-phase icing process is examined, and methodologies for solving the control equations are introduced. The numerical method is utilized for modeling mixed-phase icing under a range of conditions. The results of these simulations are then compared with data obtained from icing wind tunnel tests to assess the validity of the method. The influence of various mixed-phase conditions on ice shapes is studied. It is found that higher icing temperatures correspond to a larger icing range and amount. The increase in supercooled droplet content, ice crystal content, and ice crystal diameter all contribute to enhanced ice accretion. However, the effects of ice crystal content and diameter are relatively minor.

Frozen dough steamed products: Deterioration mechanism, processing technology, and improvement strategies.

Fresh dough products lead to instability in product quality, high production costs, and more production time, which seriously affects the industrial production of the food industry. The frozen dough technology mitigates the problems of short shelf-life and easy deterioration of quality during storage and transportation. It has shown a series of advantages in large-scale industrialization, high-quality standardization, and chain operation. However, the further development of frozen dough is restricted by the deterioration of the main components (gluten, starch, and yeast) caused by freezing. This review summarizes the main production process of frozen steamed bread and buns, and the deterioration reasons for the main component of frozen dough. The improvement mechanisms of raw ingredients, processing technology, processing equipment, and additives on frozen dough quality were analyzed from the perspective of improving gluten network integrity and yeast freeze tolerance. From prefermented frozen raw to steamed products without thawing has become the preferred production process to improve production efficiency. Wheat flour mixed with other flour can maintain the gluten network continuity of frozen dough. The freeze tolerance of yeast was improved by treatment with yeast suspension, yeast cell encapsulation, screening hybridization, and genetic engineering. Process optimization and new technology-assisted fermentation and freezing effectively reduce freezing damage. Various additives improve the freeze resistance of the gluten-starch matrix by promoting protein cross-linking and inhibiting water migration. In addition, ice structural proteins and ice nucleating agents have been proven to change the growth morphology and formation temperature of ice crystals. More new technologies and additive synergies need to be further explored.

Effect of starch categories and mass ratio of TA/starch on the emulsifying performance and stability of emulsions stabilized by tannic acid-starch complexes

This study compounded natural corn starch (CS), mung bean starch (MBS) and potato starch (PS) with tannic acid (TA) to stabilize O/W Pickering emulsion. The effect of TA/starch mass ratio (0–0.25) and three starch categories on particle properties, emulsifying properties, lipid oxidation, freeze-thaw stability, emulsion powder and digestive properties were comprehensibly investigated. In detail, the TA/starch complexes size increased gradually (91.14 nm–200.87 nm) and the hydrophobicity first increased and then decreased (TA/CS > TA/MBS > TA/PS) with increasing TA/starch mass ratio. In addition, the emulsifying ability of TA/starch complexes also increased first and then decreased with increasing mass ratio, especially TA/CS system was the best, which was the same as the hydrophobicity conclusion (θow = 80.46°). Moreover, four starch-based emulsion application characteristics were further evaluated to reveal interface structure. Compared to CS and PS system, TA/MBS emulsion had stronger ability to resist the oil oxidation (TBA = 2.54 μg/mL), destruction of ice crystal (whiter emulsion powder) and digestive enzymes (FFAs = 75.33 %). It mainly attributed to the crosslinking network structure and the highest surface load of TA/MBS complexes. This study would provide new ideas for the design and application of emulsifying properties and emulsion stability.

Changes in freezing parameters and temperature distribution of beef induced by AC electric field: Alleviation on freezing damage and myowater loss

In this study, a specialized experimental device integrating infrared thermal imaging, real-visual photography, and a time-temperature data collector was designed to investigate the effects of alternating electric field (AEF) assisted freezing on the temperature histories and freezing parameters in different layers of beef as well as the freezing damage and myowater loss. The findings revealed distinct differences in the freezing curves (e.g., slope) and parameters (e.g., Tnuc, TF, tptand Fmiz) between the surface, middle, and inner layers of beef cubes under both AEF and traditional freezing conditions. AEF treatment regulated the freezing curves and key parameters of middle and surface layers, influencing ice crystallization. The equivalent ice areas for the surface, middle, and inner samples under AEF treatment were 8.16, 14.40, and 20.56%, respectively, significantly lower than those in traditional freezing (15.87, 24.60, and 28.8%). Compared to traditional freezing, AEF-assisted freezing decreased myofibrillar fragmentation index (MFI) of beef muscle, preserving its texture integrity. AEF treatment inhibited water migration and reduced water-holding capacity (WHC) loss. In conclusion, AEF-assisted freezing changed ice formation characteristics and alleviated freezing damage by regulating the freezing curve traits and parameters.

Observation of Electrical Alignment Signatures in an Isolated Thunderstorm by Dual‐Polarized Phased Array Weather Radar and the Relationship With Intracloud Lightning Flash Rate

AbstractThe electrical alignment signatures of ice crystals in the middle and upper parts of a thunderstorm have a physical connection with the strong electric fields within the cloud. By taking advantage of the high spatio‐temporal resolution of an X‐band dual‐polarized multiparameter phased array radar, this paper employs negative KDP signatures to investigate the variation of electric fields in an isolated thunderstorm within its evolution, and the relationship between the negative KDP signatures and intracloud (IC) lightning activity. The results show that the radar‐inferred strong electric fields distributed in a region of about 8.5–10 km during the developing stage, then extended from about 10 km to the cloud top during the mature stage, with an increasing IC lightning flash rate before the end of the mature stage. Subsequently, the electric fields weakened associated with a large amount of IC lightning discharges. The qualitative analysis results indicate that the evolution of the radar‐inferred electric fields associated with the upper charge regions is consistent with the electrification process in the isolated thunderstorm, inferred by the IC lighting activity. In addition, there is a tendency for the increased IC lightning rate as the decrease in average composite KDP in the middle and upper layers of the thunderstorm, with a time lag of about 5.5 min between the minimum average composite KDP and the peak IC lightning rate, while a good correlation between the negative KDP volume and the IC lightning flash rate at a lag of approximately 9 min.

Insight into the structure-activity relationship of thermal hysteresis activity of cod collagen peptides through peptidomics and bioinformatics approaches

To elucidate the correlation between variations in thermal hysteresis activity (THA) and the physicochemical properties and structure, antifreeze peptides (AFPs) of isolated fractions (CCP-1 and CCP-2) were characterized on based peptidomics and bioinformatics. The results revealed a positive correlation between the THA of cod collagen antifreeze peptide (CCAFP) and peptide chain length, isoelectric point, and hydrophobic amino acid content. Notably, the THA of CCP-1, which has higher alkaline amino acid content, was 2.60 °C at a concentration of 10 mg/mL, significantly higher than CCP (1.90 °C) and CCP-2 (2.27 °C). Glycine, proline, and valine were the vital amino acids to the formation of hydrogen bonds. Conversely, aspartic and glutamic acids at terminal regions of AFPs tended to introduce kinks in their structures. This distortion reduced binding sites for ice crystals, thereby decreasing their THA, providing a theory for understanding the physicochemical properties and structure of AFPs that influence their THA.

Relevance of Bacteria in Causing Rain and Snow.

The Earth's climate is influenced by both natural phenomena (solar fluctuations, oceanic patterns, volcanic eruptions, and tectonic movements) and human activities (deforestation, CO and CO2 emissions, and desertification), all of which contribute to ongoing climate change and the resulting global warming. However, human actions are a major factor in exacerbating global warming and amplifying its adverse impacts worldwide. . With rising temperatures, water evaporation from water bodies and soils intensifies, leading to heightened water scarcity, particularly in drought-prone regions. This scarcity compounds rainfall deficits, posing significant challenges. Precipitation, essential for the biosphere's hydrological cycle, replenishes much of the world's freshwater. It occurs when condensed water vapor in the atmosphere falls back to Earth as rain, drizzle, sleet, graupel, hail, or snow due to gravity. Literature highlights the indispensable role of bacterial populations in this process, termed bio-precipitation. This phenomenon begins with bacterial colonization on plant surfaces, with colonies subsequently dispersed into the atmosphere by winds, triggering ice crystal formation. Through their ice nucleating property, these bacteria facilitate the growth of larger ice crystals, which eventually melt and precipitate as rain or snow. This mechanism aids in nutrient transfer from clouds to soil or vegetation. Pseudomonas syringae stands out as the most notable microorganism exhibiting this ice-nucleation property, serving as the primary source of ice nucleators driving bio-precipitation. Despite limited literature on "rain and snow-causing bacteria," this review comprehensively explores the conceptual background of bio-precipitation, the involved bioprocesses, and the critical role of bacteria like P. syringae, offering insights into future research directions.

A bite of death: Anaesthetic challenges in frostbite.

Frostbite is defined as tissue damage that is sustained as a result of prolonged exposures to less than 0°C resulting in ice crystallisation, microvascular occlusion and subsequently thrombosis. A 33-year-old mountaineer with cold burn over 20% of the total body surface area with eschar formation, acute renal failure, upper limb venous thrombosis and bilateral pleural effusion. We hereby report a successful anaesthetic management of this patient undergoing debridement and escharotomy for frostbite injuries and review its perioperative concerns. Frostbite injuries pose a challenge to the anaesthetic team due to the multi-systemic nature of its involvement.

Methodological approaches in vitrification: Enhancing viability of bovine oocytes and invitro-produced embryos.

Cryopreservation of bovine oocytes and embryos is essential for long-term preservation and widespread distribution of genetic material, particularly in bovine invitro embryo production, which has witnessed substantial growth in the past decade due to advancements in reproductive biotechnologies. Among current cryopreservation methods, vitrification has emerged as the preferred cryopreservation technique over slow freezing for preserving oocytes and invitro-produced (IVP) embryos, as it effectively addresses membrane chilling injury and ice crystal formation. Nonetheless, challenges remain and a simple and robust vitrification protocol that guarantees the efficiency and viability after warming has not yet been developed. Furthermore, although slow cooling can easily be adapted for direct transfer, an easier and more practical vitrification protocol for IVP embryos is required to allow the transfer of IVP embryos on farms using in-straw dilution. In addition, the susceptibility of bovine oocytes and embryos to cryoinjuries highlights the need for novel strategies to improve their cryotolerance. This manuscript examines various methodological approaches for increasing the viability of bovine oocytes and IVP embryos during vitrification. Strategies such as modifying lipid content or mitigating oxidative damage have shown promise in improving cryotolerance. Additionally, mathematical modelling of oocyte and embryo membrane permeability has facilitated the rational design of cryopreservation protocols, optimizing the exposure time and concentration of cryoprotectants to reduce cytotoxicity.

Damage to Mitochondria During the Cryopreservation, Causing ROS Leakage, Leading to Oxidative Stress and Decreased Quality of Ram Sperm.

Semen cryopreservation can achieve long-term preservation of sperm. Ice crystal damage, as well as oxidative stress, result in mitochondrial dysfunction and a reduction in sperm motility after thawing. However, limited information exists regarding the impact of reactive oxygen species (ROS) and mitochondria on the cryopreservation of ram sperm. The primary objective of this study was to investigate the relationship between ROS and mitochondria concerning sperm quality during the cryopreservation of ram sperm. This investigation assessed sperm motility, kinematic characteristics, membrane integrity, acrosome integrity, mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) levels, expression of mitochondrial respiratory genes (NDUFV2, SDHA, CYC1, and COXIV), ROS levels, malondialdehyde (MDA) content, phosphatidylserine externalisation rate, sperm ultrastructure, mtDNA copy number, expression of apoptosis-related genes (Bax, Caspase-3, and Caspase-8), Cytochrome C, and Caspase-3 content. The results showed the cryopreservation significantly (p < 0.05) decreased motility, kinetic parameters, membrane integrity, acrosome integrity, MMP, ATP, mRNA expression levels of mitochondrial respiratory-related genes, and significantly (p < 0.05) increased ROS levels, MDA content, phosphatidylserine externalisation rate, damage of sperm ultrastructure, mtDNA copy number, mRNA expression levels of apoptosis-related genes, Cytochrome C and Caspase-3 content compared to the fresh semen group. In conclusion, the cryopreservation causes damage to mitochondria, leading to increased ROS and subsequent oxidative stress. This process also initiates mitochondrial dysfunction and interferes with the electron transport chain, ultimately resulting in decreased MMP and ATP production. Furthermore, the liberation of Cytochrome C prompted the increase in Caspase-3 expression and subsequent sperm apoptosis occurred, ultimately leading to a deterioration in sperm quality after thawing.

Evaluation of the Aggregation Efficiency Modeling at Colder Atmospheric Temperatures in Comparison to Satellite Observations

Abstract Aggregation efficiency in the upper troposphere is highly uncertain because of the lack of laboratory experiments and aircraft measurements, especially at atmospheric temperatures below −30°C. Aggregation is physically broken down into collision and sticking. In this study, theory-based parameterizations for the collision efficiency and sticking efficiency are newly implemented into a double-moment bulk cloud microphysics scheme. Satellite observations of the global ice cloud distribution are used to evaluate the aggregation efficiency modeling. Sensitivity experiments of 9-day global simulations using a high-resolution climate model show that the use of collision efficiency parameterization causes a slight increase in the cloud ice amount above the freezing level over the tropics to midlatitudes and that the use of our new sticking efficiency parameterization causes a significant increase in the cloud ice amount and a slight decrease in the snow amount particularly in the upper troposphere over the tropics. The increase/decrease in the cloud ice/snow amount in the upper troposphere over the tropics is consistent with the vertical profile of radar echoes. Moreover, the ice fraction of the cloud optical thickness is still underestimated worldwide. Finally, the cloud radiative forcing increases over the tropics to reduce the bias in the radiation budget. These results indicate that our new aggregation efficiency modeling reasonably functions even at atmospheric temperatures below −30°C; however, further improvements in the ice cloud modeling are needed. Significance Statement Long-standing biases in the radiative budget in climate models indicate the existence of a missing mechanism to realistically represent the ice cloud growth in the upper troposphere. This study focuses on aggregation efficiency, which has been assumed to be a tuning parameter to optimize the global radiative budget. Therefore, this study employs a theory-based parameterization to calculate the aggregation efficiency. According to the parameterization, aggregation efficiency in high clouds varies by the growth stage of the individual ice particles. As a result, small ice crystals are likely to grow more slowly, and the lifetime of cirrus clouds is prolonged to enhance cloud radiative forcing, particularly over the tropics. These results are promising for reducing the biases observed in climate models.

Influence of low voltage programmed thawing on the quality of frozen pork and its myofibrillar protein

This study explored the effects of low voltage programmed thawing (LVPT) on thawing period, water status, current density as well as physicochemical properties of porcine longissimus dorsi muscle, considering air thawing (AT), water immersion thawing (WT) and cold storage thawing (CST) for the comparison, additionally making fresh meat (FM) as the control. The thawing process used current limiting to gradually reduce the maximum output current to 500, 200 and 100 mA, respectively, by applying a safe voltage of 35 V in a home defrosting apparatus. Using two pairs of foil plate, the thawing (LVPT-2) with dual current loop accelerated the melting of ice crystals than the process with one pair of polar plate (LVPT-1) with one current loop. From −18 °C to −1 °C, the thawing period of LVPT-2 was reduced by 14.54 %, 11.72 %, and 15.95 % compared with that of LVPT-1 for samples within the thickness of 2, 3 and 4 cm, respectively. During the process, the intensity and density of the current loaded on the frozen meat gradually increased. LVPT-1 retained water and reduced its migration inside the meat, and protein solubility was better maintained. As the thickness increased, the effect of LVPT-2 on the moisture distribution and protein solubility of the sample decreased. LVPT-1 treatment resulted in less fat oxidation as well as stable secondary and tertiary structures of myofibrillar proteins compared to other treatments. At low voltage, the ability of LVPT −2 to maintain meat quality was reduced due to the increase in current density. In addition, LVPT-1 reduced muscle damage because of rapid melting of ice crystals. In contrast, LVPT-2 was conductive the formation of hot spots due to dual current loop passed through the pork in final phase of thawing, which would adversely influence the quality of thawed meat. Finally, LVPT could improve the rate of thawing, water binding capacity and meat quality, especially, there was no overheating effect on the meat because of current limiting.

Amine-impregnated elastic carbon nanofiber aerogel templated by bacterial cellulose for CO2 adsorption and separation

Carbon aerogel has become a promising electrode material for CO2 capture and capacitor due to its large specific surface area, well-developed pore structure, adjustable porosity and ultra-high specific power. However, most of the carbon-based materials suffer from poor mechanical properties, low recycling efficiency, and low adsorption capacity, making it difficult to be put into industrial applications on a large scale. Bacterial cellulose (BC) has an ultra-fine reticular structure, a modulus of elasticity that is several to more than ten times that of typical plant fibers, and high tensile strength. In this paper, BC was treated by unidirectional freeze-drying method, and the aerogels with ordered honeycomb pore structure were constructed by unidirectional growth of ice crystals, and the pyrolytic chemical properties of BC were adjusted by using (NH4)2SO4, which effectively prevented the shrinkage and deformation of materials during carbonization, and successfully prepared elastic nanocarbon fiber aerogels. At the same time, the introduction of (NH4)2SO4 made the material realize N doping in the carbonization process, providing more adsorption sites, which was conducive to the adsorption of CO2. Finally, the carbon fiber nanoaerogel was modified by TEPA to further improve its adsorption selectivity for CO2. The prepared elastic carbon nanofiber aerogel (CBCNT) has high CO2 adsorption performance and high selectivity, and its CO2 capture capacity is up to 4.88 mmol/g. At the same time, its capacitance also reached 246F/g.

Enhanced gelation of sturgeon frozen surimi via egg white: Exploring the role of endogenous serine protease inhibition

AbstractThe degradation of frozen sturgeon surimi can be attributed to the endogenous serine protease. This study was first to examine the impact of egg whites on the frozen sturgeon surimi's gel properties from the perspective of inhibiting endogenous serine protease. The protease activity of egg whites group (CA + EW group, consisting of 4% egg whites and cryoprotectants) was 45.15% lower than that of cryoprotectants group (CA group, consisting of 3% sucrose, 3% sorbitol, and 0.3% sodium tripolyphosphate) at 12 weeks. From the results of inhibition kinetics, serine protease was inhibited by both anticompetitive and noncompetitive inhibition modes. Molecular docking analysis indicated that egg white achieves this inhibitory effect through ionic interactions and hydrogen bonding with serine protease. However, this inhibitory effect was absent when the freezing period was extended to 24 weeks. Compared with CA group, the CA + EW group exhibited 54.76% and 4.59% increase in gel strength and water‐holding capacity, and 32.42% reduction in cooking loss after 24 weeks of freezing. Egg whites also impeded water migration and enhanced the density and smoothness of the gel microstructure, reducing protein aggregation. These results indicated that egg whites serve a dual function: inhibiting serine protease and filling the gel network within 12 weeks, mitigating protein aggregation and ice crystal formation over 24 weeks. This study elucidated the mechanism underlying the impact of egg white on endogenous serine protease in sturgeon surimi during long‐term freezing, laying a theoretical foundation for the industrialization of sturgeon surimi.

Adding lignin to bagasse cellulose-based materials increases the wet strength and reduces micro-nano scale wet low-temperature defects

The enhancement of cellulose utilization in agricultural by-products, such as bagasse, holds significant importance in augmenting the value of secondary agricultural products. However, cellulose-based materials have limited application potential owing to their low strengths under wet and wet-low-temperature conditions. Improved mechanical properties of cellulose-based materials at wet and low temperatures can significantly enhance their suitability for application in cold chain processes. Furthermore, the effects of wet cryogenic conditions on cellulose-based materials are not well understood. In this study, composite films composed entirely of biomass are prepared via the co-solubilization of lignin and bagasse cellulose and then cured via hot pressing, which increases the wet and wet low-temperature strengths of the films. Furthermore, the mechanism by which cellulose/ lignin content influences the wet-low-temperature defects of films was investigated. Lignin self-polymerizes and hot pressing causes cross-linking in the cellulose-based films, which improves their performance in wet low-temperature environments. Furthermore, the micromorphologies, specific surface areas, and moisture distribution patterns of the cellulose films after wet -low-temperature treatment were investigated. The results indicate that cross-linking prevents large amounts of micro-nano scale free-water from entering the cellulose-based material, thereby preventing the formation of ice crystals at low temperatures, which can damage the microstructure. The results of this study can be used to develop bagasse cellulose/cellulose-based materials for applications in humid and low-temperature environments.

Comparison of in-vacuum micro-PIXE and in-air micro-PIXE for unfixed plant sample

PIXE analysis is very useful for the simultaneous determination of various elements. Typically, when micro-PIXE analysis of biological samples with high water content is performed in a vacuum, freeze-drying methods are used to fix the structure and remove any ice crystals present in a controlled manner to prevent changes or redistribution of elemental content in the sample. This method is essential for cell size analysis. However, we considered that fixation is not always necessary for macroscopic analysis of plant tissue size. Therefore, we investigated the extent to which elemental density changes with vacuum extraction from elemental density ratios obtained from micro-PIXE analysis of Arabidopsis thaliana leaves in-air and in-vacuum. The deformation caused by beam irradiation and the quantitative changes of C, O, and H in the samples were also evaluated by STIM and RBS analyses of Arabidopsis thaliana petal.

Correlation between Peak Height of Polar Mesospheric Clouds and Mesopause Temperature

Polar mesospheric clouds (PMCs) are ice crystal clouds formed in the mesosphere of high-latitude regions in both the northern (NH) and southern hemispheres (SH). Peak height is an important physical characteristic of PMCs. Satellite observation data from solar occultation for ice experiments (SOFIE) during seven PMC seasons from 2007 to 2014 show that the difference between the height of the mesopause and the peak height of the PMCs (Zmes-Zmax) were inversely correlated with the atmospheric mesopause temperature. The Zmes-Zmax averages for all seasons for the NH and SH were 3.54 km and 2.66 km, respectively. They were smaller at the starting and ending stages of each PMC season and larger in the middle stages. Analysis of the individual cases and statistical results simulated by the PMCs 0-D model also revealed the inverse correlations between the Zmes-Zmax and mesopause temperature, with correlation coefficients of −0.71 and −0.62 for the NH and SH, respectively. The corresponding rates of change of Zmes-Zmax with respect to mesopause temperature were found to be −0.21 km/K and −0.14 km/K, respectively. The formation mechanism of PMCs suggests that a lower temperature around the mesopause can lead to a greater distance and longer time for ice crystals to condense and grow in clouds. Thus, ice crystals sediment to a lower height, making the peak height of the PMCs further away from the mesopause. In addition, disturbances in small-scale dynamic processes tend to weaken the impact of temperature on the peak height of PMCs.

Supercooling-Driven Homogenization and Strengthening of Hydrogel Networks.

By leveraging principles from metal grain refinement, we introduce a transformative technique for fabricating poly(vinyl alcohol) (PVA) hydrogels via supercooling-coupled wet annealing, significantly enhancing their mechanical robustness and isotropy while maintaining their exceptionally high water content. Our methodology involves the dissolving PVA in water at elevated temperatures, mirroring the homogeneity achieved with a molten metal, in order to ensure a uniform distribution of polymer chains. This uniformity facilitates a rapid cooling phase that generates ultrafine ice crystals, setting the stage for a crucial solvent exchange with ethylene glycol (EG). The EG-mediated supercooling technique ensures the polymer homogeneity and structure integrity and induces the PVA chains to aggregate and form high-density hydrogen bonds, leading to a uniformly distributed, interconnected PVA network with high crystallinity. The process is further strengthened by EG-enabled wet annealing, which promotes the formation of densely packed crystalline domains within the polymer network. This rigorous process yields PVA hydrogels with superior mechanical properties, including a tensile strength of 13.65 MPa and a fracture toughness of 35.39 MJ m-3, alongside remarkable water content nearing 80%. These advances not only surpass the capabilities of conventional hydrogels but also broaden their application potential, highlighting the innovative integration of supercooling principles in polymer science.

Estimation of the Uncertainty in Daytime Cirrus Cloud Radiative Forcing and Heating Rates Due to Ice Crystal Optics

Abstract The uncertainties in absolute daytime top-of-the-atmosphere (TOA) net cirrus cloud radiative forcing (CRF) and radiative heating rates are estimated at five Micro-Pulse Lidar Network (MPLNET) sites spanning the tropics to high-latitudes. One year of semi-transparent cirrus cloud (optical depth &lt; 3.0 and cloud top temperature &lt; −37 °C) measurements are subject to spectrally-consistent optical properties for nine different ice crystal habits, thus providing a range of possible forcing values. The annual average absolute daytime TOA net CRF is positive at Barbados, Kanpur, and, Singapore (0.59–0.67, 0.61–0.65, and 1.94–2.09 W∙m−2, respectively), negative at Fairbanks (−0.67 to −0.28 W∙m−2), and can regularly become positive or negative at Goddard Space Flight Center (GSFC) (−0.06 to 0.32 W∙m−2). The TOA CRF depends on ice crystal shape; in particular, plates lead to relatively large absolute values that decreases for bullet rosettes and columns. Uncertainties in daytime cirrus cloud radiative properties are estimated as the standard deviation of all possible outcomes when considering the different particle habits individually. Annually, the average uncertainty of the absolute daytime TOA net CRF ranges from 0.50–1.80 W∙m−2. In-cloud daytime net radiative heating rates are positive, on average, at all five sites (0.25–3.84 K/day) and have an estimated uncertainty of less than 0.30 K/day. The uncertainties in cirrus radiative forcing and heating that are characterized by assumptions regarding the ice crystal optical properties must be considered in downstream applications, including satellite retrievals and numerical weather prediction.

Mechanisms, Applications, and Challenges of Utilizing Nanomaterials in Cryopreservation

Cryopreservation of biological samples, including cells, tissues, and organs, has become an essential component in various biomedical research and applications, such as cellular therapy, tissue engineering, organ transplantation, and conservation of endangered species. However, it faces critical challenges throughout the cryopreservation process, such as loading/unloading of cryoprotective agent (CPA), ice inhibition during cooling, and ultrafast and uniform heating during rewarming. Applying nanomaterials in cryopreservation has emerged as a promising solution to address these challenges in each step due to their unique properties. For instance, in order to deliver nonpermeating CPA into cells, some nanomaterials, such as polymeric nanocapsule, can carry nonpermeating CPA to penetrate into the cells, regulating the intracellular ice crystal. During cooling, some nanomaterials, such as graphene oxide, can bind to basal or prism planes of ice crystals, suppressing the ice growth. During rewarming, some nanomaterials, such as magnetic nanoparticles, can improve the heating performance, preventing devitrification and recrystallization during rewarming. However, challenges in nanomaterials‐assisted cryopreservation remain, including the need for comprehensive studies on nanomaterials toxicity and the development of scalable manufacturing processes for industrial applications. This review examines the role of nanomaterials in cryopreservation, focusing on their mechanisms, applications, and associated challenges.