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Abstract A thorough understanding of droplet impact and freezing is vital in preventing ice accretion on many outdoor devices. This simulation-based study investigated the effect of surface morphology on the impacting-freezing process of a supercooled droplet. Also, the variations of Weber number and supercooling temperature were studied numerically. The droplet impact and freezing process were simulated with the volume of fluid method and freezing model. A more accurate simulation was achieved by modeling the supercooled droplet and the dynamic contact angle. At the given ranges of the input parameters, the main factors that guaranteed droplet rebounding after collision were determined. The supercooling temperature and the groove width should be above 266 K and less than 0.21 mm, respectively. The droplet should also maintain its cohesion and integrity during impact. Creating grooves on a surface is novel and paves a new way to understand the impact and solidification of water droplets in supercooled conditions.

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

A thorough understanding of droplet impact and freezing is vital in preventing ice accretion on many outdoor devices. This simulation-based study investigated the effect of surface morphology on the impacting-freezing process of a supercooled droplet. Also, the variations of Weber number and supercooling temperature were studied numerically. The droplet impact and freezing process were simulated with the volume of fluid method and freezing model. A more accurate simulation was achieved by modeling the supercooled droplet and the dynamic contact angle. At the given ranges of the input parameters, the main factors that guaranteed droplet rebounding after collision were determined. The supercooling temperature and the groove width should be above 266 K and less than 0.21 mm, respectively. The droplet should also maintain its cohesion and integrity during impact. Creating grooves on a surface is novel and paves a new way to understand the impact and solidification of water droplets in supercooled conditions. [ABSTRACT FROM AUTHOR]

This study presents a detailed numerical modeling of the freezing within a cold storage unit enhanced by the incorporation of fins and CuO nanoparticles. The presence of fins meaningfully improves the thermal efficiency of the unit, while the addition of nano-powders further accelerates the solidification. Various concentrations (ϕ) and diameters (dp) were considered to evaluate their impact on the solidification rate. The mathematical model for this process was developed under two key assumptions: that the thermophysical properties could be accurately predicted using a homogeneous mixture model and that convective effects within the system were negligible. The FEM molding's accuracy was confirmed through rigorous verification tests. One of the novel aspects of this study is the adaptive grid configuration, which evolves over time to accurately track the advancing ice front during the freezing process. The results indicated that the introduction of CuO nano-powders led to a substantial decrement in the completion time about 41.59 %. In the optimal scenario, full freezing was achieved in just 131.56 s, compared to 225.27 s for the base case with water alone. Additionally, the study found that the performance of the cold storage unit was highly dependent on the size of the nanoparticles. An intermediate nanoparticle diameter provided the best performance, with a 19.93 % reduction in freezing time initially observed as dp increased.

The intensification of freezing rates through the incorporation of nano-sized powders and fins through a cold storage unit was examined. The Galerkin method with special meshing was utilized to solve equations, which were based on the supposition of conduction mode dominance. Additives of varying diameters (dp) and three different concentration levels (ϕ) were implemented. The findings are presented through ice front visualization, contour plots, and scalar curves. The computational code demonstrated high accuracy during the validation phase. The results reveal that as the dp increases, the solidification time initially drops by approximately 20 %, then subsequently increases by about 49.45 %. The optimal solidification time of 2951.17 s was achieved with medium-sized powders. Furthermore, an intensification in (ϕ) leads to a significant decrement in freezing time by about 41.43 %, with the most pronounced effect observed for nano-powders with dp = 40 nm.

Because the thermal conductivity of freezing soil is hard to measure, in order to clarify the influence of temperature on thermal conductivity, a hyperbolic model with three parameters was proposed to describe the relationship between thermal conductivity and negative temperature in this paper. Then, the performance of the new hyperbolic model was verified by the measured thermal conductivity coefficients and three widely used models, and a sensitivity analysis of model parameters was performed. The results show that the hyperbolic model can accurately predict the change pattern of soil thermal conductivity during the freezing process. Among these four models, the proposed hyperbolic model has the smallest root mean square error and relative error. The model parameters are closely related to the fine particle content and decrease as the initial volume moisture content increases. Considering the new model can accurately simulate the variation of thermal conductivity with subzero temperature, it can provide a basis for coupled heat and mass transfer in cold regions. [ABSTRACT FROM AUTHOR]

The most crucial variables that influence the characteristics and quality of cotton fibers during the cotton growth and ginning processes are temperature and moisture regains. Here the cotton fiber samples were generated with pre-treatment using a synergistic strategy of moisture regains and low temperatures, the morphology and structure of the fibers with different pre-treatments were analyzed by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray Photoelectron Spectrometer (XPS), X-ray diffraction (XRD), and Carbon-13 Nuclear Magnetic Resonance Spectrometry (13C NMR). Further, the mechanical properties of the cotton fibers were evaluated using LLY-06E tensile. The results shown that, with 3 days of freezing in -18℃, the linear density variation of the cotton fiber samples reached maximum, and the surface of the fibers showed noticeable fractures, local holes, and folded damage. Moreover, the low temperature and high moisture regain caused the internal water molecules of the cotton fibers interact in complex ways, altering the intermolecular forces but without changing the chemical composition. This research expands the temperature field of cotton fibers, particularly in the ginning process, by investigating the damage to the mechanical characteristics of cotton fibers caused by the combined effect of low temperature and moisture regain. [ABSTRACT FROM AUTHOR]

The changes of freezing curve and moisture uniformity during the freezing process of dough with different water(40%, 45%, 50% and 55%) additions at -18 ~ 25 T were studied, and the effects of ice crystal growth on the network structure of gluten protein and the chemical forces during dough freezing were studied with 45% water addition as an example. The results showed that: the moisture uniformity showed a decreasing trend with different water additions during the dough freezing process. With the increase of water addition, the freezing rate of the dough first increased and then decreased, and the freezing rate was fastest when the water addition was 45%. With the decrease of temperature, the number decreased during the freezing process, the average pore area of ice crystals in the dough with 45% water addition increased, and it increased rapidly in the temperature range of -6 °C to -9 °C; The number of pores decreased continuously, the branching rate of gluten protein network structure parameter gradually decreased from 2.20x10-3 to 1.90x10-3, and the endpoint rate gradually increased from 2.10x10-3 to 2.40x10-3. The hydrogen bonds, ionic bonds, and disulfide bonds between gluten protein network gradually weakened, and the gluten protein network was destroyed. [ABSTRACT FROM AUTHOR]

Adding endogenous antioxidants to the diluent is significantly associated with semen quality during the freezing process. This study aimed to investigate the effects of adding glutathione to AndroMed diluent on the preservation of crucial sperm attributes, namely, intact plasma membrane (IPM), intact acrosome membrane (IAM), and progressive motility of Bali cattle spermatozoa. A completely randomized design was used, and spermatozoa samples were obtained from a Bali cattle and divided into two diluent treatment groups (36 diluent samples in each group with six replications), namely pure AndroMed as the control and a group with the addition of glutathione (1 mmol) to AndroMed. Each treatment was replicated six times and evaluated at three freezing stages, including postdilution, post-equilibration, and post-thawing, for crucial sperm properties. The results indicated that fresh Bali cattle spermatozoa had progressive motility, IAM, and IPM of 75%, 89%, and 88%, respectively. During the freezing process, there was a significant decrease in semen quality, including progressive motility, IAM, and IPM of spermatozoa after dilution to post-equilibration and post-equilibration to post-thawing in both treatment groups. Meanwhile, the addition of 1 mmol of glutathione to AndroMed diluent had a significant difference in increasing progressive motility, IAM, and IPM of Bali cattle spermatozoa at each stage of semen freezing, including postdilution, post-equilibration, and post thawing when compared with controls. Based on the results, it can be concluded that adding 1 mmol of glutathione to the AndroMed diluent enhanced the quality and integrity of Bali cattle semen, including progressive motility, IAM, and IPM during the freezing process. [ABSTRACT FROM AUTHOR]

The effect of frozen storage at a commercial temperature (−30°C) on the nutritional characteristics of the blue swimming crab Portunus segnis for a period of 120 days was investigated. Lipid and protein oxidation was investigated by analyses of peroxide value, thiobarbituric acid reactive substances, free fatty acids, and advanced oxidation protein products. Results showed significant lipid deterioration with extended storage time and changes in fatty acids composition and lipid classes. From a nutritional standpoint, it would be preferable for human consumption to eat frozen crabs for no more than 30 days as they retain a higher nutritional value. [ABSTRACT FROM AUTHOR]

Frozen storage is an important strategy to maintain meat quality for long-term storage and transportation. Lipid oxidation is one of the predominant causes of the deterioration of meat quality during frozen storage. Untargeted lipidomic and targeted metabolomics were employed to comprehensively evaluate the effect of frozen duration on pork lipid profiles and lipid oxidative products including free fatty acids and fatty aldehydes. A total of 688 lipids, 40 fatty acids and 14 aldehydes were successfully screened in a pork sample. We found that ether-linked glycerophospholipids, the predominant type of lipids, gradually decreased during frozen storage. Of these ether-linked glycerophospholipids, ether-linked phosphatidylethanolamine and phosphatidylcholine containing more than one unsaturated bond were greatly influenced by frozen storage, resulting in an increase in free polyunsaturated fatty acids and fatty aldehydes. Among these lipid oxidative products, decanal, cis-11,14-eicosenoic acid and cis-5,8,11,14,17-dicosapentaenoic acid can be considered as potential indicators to calculate the freezing time of unknown frozen pork samples. Moreover, over the three-month frozen storage, the first month was a rapid oxidation stage while the other two months were a slow oxidation stage. [ABSTRACT FROM AUTHOR]

The lakes in cold areas usually undergo a long period of frozen conditions during which the physicochemical environment and biological community will undergo significant changes. To understand the characteristics of the bacterioplankton community in a frozen lake, we collected 28 ice samples and 39 water samples from under the ice sheet (including two ice layers and three water layers) in Dali Lake, an inland closed lake on the Inner Mongolia Plateau, Northern China. Based on 16S-rRNA gene-based high throughput sequencing coupled with comparisons of physicochemical proxies between "ice" and "water" samples, the vertical characteristic of the bacterioplankton community from ice to water were investigated in detail. The results of the analysis show that the contents of total nitrogen, total phosphorus, dissolved inorganic phosphorus, total dissolved phosphorus, electrical conductivity, and dissolved oxygen were visibly higher in water samples than in ice samples. Correspondingly, the ice sample abundance indices (the Chao and Ace proxies) were higher than those in water, but the water sample evenness and diversity indices (the Shannon evenness, Shannon, and Simpson indices) were higher than those in ice. In addition, the Proteobacteria, Actinobacteria, Cyanobacteria, Bacteroidetes, Verrucomicrobia, and Tenericutes were the dominant bacterioplankton phyla both in ice and water samples. However, the Proteobacteria was the most abundant bacterioplankton phylum in ice samples (the average relative contents were 87.8% and 67.8% in surface ice and bottom ice, respectively), and the Actinobacteria was the most abundant bacterioplankton phylum in water samples (the average relative contents were 42.0%, 43.1%, and 45.6% in surface water, middle water, and bottom water, respectively). The ecological network of bacterioplankton was significantly different in five types of samples during the freezing period. The results revealed a higher proportion of positive interactions in the entire lake and a higher connectivity in ice than in water. Actinobacteria was the most connected and most critical phylum for maintaining community function. Finally, the bacterioplankton community composition was evidently controlled by environmental factors. In Dali Lake, the changes in phosphorus had higher correlations with bacterioplankton in ice samples, and the changes in nitrogen had higher correlations with bacterioplankton in water samples. Concomitantly, the genera that played key roles in ice samples were not the same as those in water samples that had experienced the frozen conditions. Taken together, these data will provide evidence as to how a bacterioplankton community responds to environmental changes in a frozen lake. [ABSTRACT FROM AUTHOR]

Research on methane and carbon dioxide emissions mainly focuses on industrial emissions, cultivated land, and wetlands, while few studies have studied freezing-related emissions. This paper presents field experiments conducted during soil freezing to measure carbon dioxide and methane concentrations in the air, near the soil surface, and in the soil. In addition, the influence of precipitation, snowfall, air temperature, and depth of freezing on gas emissions was analyzed. We observed increased concentrations of methane and carbon dioxide in soil and air at soil freezing and snow cover growth. For the first time, an increase in gas flux during soil freezing was found in the absence of permafrost. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to select the appropriate ultrasound parameters that support the freezing process of Bo Chinh ginseng. This process involves placing Bo Chinh ginseng in an open-air environment and ensuring that the transducer does not come into contact with the material. The research results show that the ultrasound power, ultrasound irradiation temperature and intermittency ratio all affect the freezing time, nucleation temperature, color and microstructure of the materials. When the ultrasound continuously operated during the freezing process, at a frequency of 20 kHz, there was a 29.1% reduction in the freezing time at a power level of 100 W as compared to freezing without the help of ultrasound irradiation. The irradiation temperature and nucleation temperature have a linear relationship (y=−0.35x−0.93) which can help to control the nucleation temperature, thereby changing the ice crystal size. Ultrasound-assisted freezing at a 0.6 intermittency ratio had the shortest freezing time. The microstructure of the material changed after ultrasound-assisted freezing and many microchannels and holes were generated. When frozen at a wave rate of 0.4, the microchannels that were created in the material effectively supported the process of water drainage in the drying sublimation stage. At the same time, ultrasound irradiation did not affect the color of the post-freezing material when compared to the color of the frozen material that did not undergo ultrasound irradiation.

To reduce ice adhesion hazards, optimize or develop the anti/de-icing methods, it is necessary to understand the change of freezing parameters during the freezing process, such as thermodynamic, morphological, and mechanical parameters. The present study investigates the freezing characteristics by purpose-built devices to describe the freezing process quantitatively. Morphological parameters were calculated the reverse engineering. The results showed that the inner temperature and morphology of water droplet were obviously changed, and the freezing process could be mainly divided into three stages: initial and spreading, freezing, and steady-state. Moreover, an experimental apparatus that measured the phase swelling force was built on investigating the freezing process of water from the mechanical aspect. It was found that the swelling force generated from the freezing process of 2473 mm3 water could reach 46.38 N. The generation process of swelling force could also be separated into three stages: non-expansive stage, increasing stage, and stable stage. The formation stage of swelling force was similar to that of ice. Combining the measured expansion force with the calculated freezing parameters based on the observed test, the freezing process of water could be better understood. The study would help researchers and engineers understand the freezing process and provide some freezing characteristics parameters for the anti/de-icing research. [ABSTRACT FROM AUTHOR]

Artificial Insemination (AI) programs using qualified semen are designed to revolutionize the poultry farming sector by targeting genetic improvement along with appropriate health strategies. Hence, a prolonged preservation method of quality sperm conserves is important for successful AI outcomes. The objective of this study was to compare the effects of different type of containers; straw, cryovial tubes and pellet on the quality of the frozen-thawed Thai native chicken (Pradu-hangdum) semen. High-quality pooled semen was collected and divided into 4 groups with 12 replicates: semen preserved with BHSV extender in 1) 0.25 mL straw, 2) 0.5 mL straw, 3) 2 mL cryovial tube, and 4) semen pellet in 2 mL cryovial tube. All containers were stored in a liquid nitrogen tank for 1 week and the frozen-thawed sperm were subsequently analyzed. The results indicated that the mean of all motion parameters including total motility, progressive motility, progressive fast motility and progressive slow motility, and some kinetic parameters such as DCL, DSL, ALH, BCF, and HAC of the frozen-thawed sperm preserved in cryovial tube had significantly higher values compared to other groups (P < 0.05). In conclusion, semen freezing process in cryovial tubes had the least effect on decreasing the qualities of frozen-thawed sperm than other methods. Furthermore, fertility rates related to chicken semen preservation should be further evaluated to provide valuable knowledge to farmers. [ABSTRACT FROM AUTHOR]

Frozen storage is an important strategy to maintain meat quality for long-term storage and transportation. Lipid oxidation is one of the predominant causes of the deterioration of meat quality during frozen storage. Untargeted lipidomic and targeted metabolomics were employed to comprehensively evaluate the effect of frozen duration on pork lipid profiles and lipid oxidative products including free fatty acids and fatty aldehydes. A total of 688 lipids, 40 fatty acids and 14 aldehydes were successfully screened in a pork sample. We found that ether-linked glycerophospholipids, the predominant type of lipids, gradually decreased during frozen storage. Of these ether-linked glycerophospholipids, ether-linked phosphatidylethanolamine and phosphatidylcholine containing more than one unsaturated bond were greatly influenced by frozen storage, resulting in an increase in free polyunsaturated fatty acids and fatty aldehydes. Among these lipid oxidative products, decanal, cis-11,14-eicosenoic acid and cis-5,8,11,14,17-dicosapentaenoic acid can be considered as potential indicators to calculate the freezing time of unknown frozen pork samples. Moreover, over the three-month frozen storage, the first month was a rapid oxidation stage while the other two months were a slow oxidation stage.

Freezing processes have long been employed for the preservation of foods, providing minimum nutrition loss with a long shelf life period. Freezing plays an essential role in ensuring the safety of food products in all regions of the world. Nonetheless, slow freezing rates and frequently freezing/thawing lead to permanent physicochemical changes, damage of structure, degradation of nutrition values, and color changes through the formation of large ice crystals in food matrix during the cold storage. The size of ice crystals is highly related to the duration of phase transition and degree of supercooling. This paper reviews that the degree of supercooling and nucleation temperature can be controlled by positive or negative pressure and vibration of the dipole and dipole rotation water molecule techniques. Controlling nucleation temperature and suppression of ice crystals in the food matrix could not be achieved by current freezing methods such as air blast, contact, and immersion freezing in the food industry. These present freezing methods are especially focused on increasing the heat transfer rate in foods. Rapid freezing technology may depend on the size and shape of food. However, the size of ice crystals and the suppression of nucleation could be achieved by alternative freezing technologies to overcome the drawbacks of current freezing technologies in the food industry. Conventional freezing technologies can be replaced by emerging freezing techniques, ultrasound irradiation, high pressure, electric field, magnetic field, and microwave-assisted freezing to control the properties of the nucleation and degree of supercooling in the food industry. [ABSTRACT FROM AUTHOR]

Frost heave experiments on saturated sandstone and tuff with an open crack are conducted under uniform and unidirectional freezing conditions. Frost heave of crack in sandstone with high permeability is more significant under uniform freezing condition than that under unidirectional freezing condition. However, frost heave of crack in tuff with low permeability is more significant under unidirectional freezing condition. To illustrate the reasons for this phenomenon, a numerical model on the freezing processes of saturated rock with an open crack considering the latent heat of pore water and water in crack is proposed and confirmed to be reliable. Numerical results show that a frozen shell that blocks the migration of water in crack to rock develops first in the outer part of the rock before the freezing of water in crack under uniform freezing condition. However, the migration path of water in crack to the unfrozen rock under freezing front exists under unidirectional freezing condition. The freezing process and permeability of rock together determine the migration of water in crack and lead to the different frost heave modes of crack for various permeable rocks under different freezing conditions. The frost heave modes of crack in rock with low or high permeability are similar under uniform freezing condition because water migration is blocked by a frozen shell and is irrelevant to rock permeability. For high permeability rock, the frost heave of crack will be weakened due to water migration under unidirectional freezing condition; however, the frost heave of crack would be more significant for low permeability rock because water migration is blocked under unidirectional freezing condition. Therefore, the freezing condition and rock permeability determine the frost heave of rock with crack together, and this should be concerned in cold regions engineering applications. [ABSTRACT FROM AUTHOR]

The freezing process can be industrially performed to extend shelf life and to improve exportability of Italian high-moisture Mozzarella cheese. This cheese is usually characterized by a non-regular spheroidal shape that may be responsible for local differences of temperature on the surface and that can influence the overall freezing time. In this work, Mozzarella freezing was modelled by coupling the finite element method and a photogrammetric procedure that permitted to reconstruct the three-dimensional domain of the product. Computational models were validated by performing experimental trials, and results were accurate (root mean square error < 1.47°C). With the photogrammetric technique it was possible to estimate volume, surface area, shape and size of the cheeses, and to study temperature-surface distribution that was found to be non-homogeneous. Freezing models highlighted that the surface area-to-volume ratio of the product, that ranged between 1.09 and 1.15 cm-1, is one of the most critical parameters that define the freezing time of the cheese. A geometrical approximation of the cheese based on the surface area-to-volume ratio, showed good accuracy in terms of freezing times. These models can be valuable for Mozzarella cheese freezing optimization and design, to recover efficiency and to improve quality. [ABSTRACT FROM AUTHOR]

We presented both experimental and numerical studies on the freezing of impacting water droplets on a cold surface at different surface temperatures. The numerical model consists of two parts. The first one is to determine the temperature evolution of the droplet prior to the occurrence of freezing by solving the heat conduction equation, and the second one is to simulate the freezing process via an extended phase change model. Experiments were conducted to observe and record the freezing process. The droplet profile and the propagation of moving water–ice interface during freezing were obtained from image analysis. Based on the numerical pre-recalescence temperature of the droplet, the average initial ice fraction and local initial ice fraction were obtained. Then, both the two kinds of initial ice fractions were used to figure out the difference that they brought to the predicted freezing process. Through a comparison of the experimental observations and the numerical predictions, the freezing process predicted by using local initial ice fraction showed a better agreement with the experiment than using average initial ice fraction. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the efficiency of microencapsulated apple polyphenols (MAP) in controlling cathepsin activity and texture, as well as inhibiting protein oxidation and metmyoglobin formation in lamb meat during frozen storage at −18 °C for 40 weeks. The effects of degradation in vitro on cathepsin and the microstructure in lamb were also evaluated. Results indicated that relative to the control group, the lamb treated with MAP exhibited increased cathepsin activity and inhibited metmyoglobin production. Textural characteristics, such as hardness and springiness, significantly changed (p < 0.05). Treatment with 0.2–1.6 mg/mL of MAP effectively reduced the mean particle size, increasing the zeta potential, delaying the conversion of α-helices to random coils, and maintaining the integrity of the tissue structure. However, treatment with 3.2 mg/mL of MAP damaged the protein structure. Degradation in vitro indicated that protein oxidation hindered the effect of cathepsin and was a dominant factor affecting protein during the frozen storage. These results demonstrated that microencapsulation can potentially be used for meat preservation and replace chemical antioxidants in the meat industry.

This study proposes a novel anti-icing model in which silicone rubber with low thermal conductivity is coated at different positions on a material surface to change the continuity of the thermal conductivity of the surface. During the test, the surfaces of aluminum alloy and polymethyl methacrylate (PMMA) are discontinuously coated with silicone rubber. Repeated experiments are conducted to verify the anti-icing effect of the proposed model. Results showed that compared to the conventional surface ice adhesion strength, the rate of reduction of the ice adhesion strength of the aluminum alloy and PMMA could reach 75.07% and 76.70%, respectively, when the novel method is used. Because of the different levels of thermal conductivity at different positions on the material surface, the water attached to the surface locations without the coated silicone rubber had other freezing times. Combined with the heat and phase change of water during the freezing process, changing the stability of the interface between the ice and substrate could act as an active anti-icing power. The ice adhesion strength on the material surface could then be reduced. Compared with the conventional anti-icing methods, the anti-icing method proposed in this study could significantly increase the active anti-icing characteristics of the material and provide a novel anti-icing method for use in engineering applications.

A widely used approach to preserving genetic diversity in birds involves the cryopreservation of semen. In this process, cells are subjected to physical and chemical stresses, but not all cell species respond equally. Many studies have been published on the freezing–thawing of sperm cells from a wide variety of domestic and wild species, on issues ranging from the sperm quality to different protocols, fertilisation success rates, etc. Nevertheless, very little information is available on the common pheasant. To fill this gap, the aim of this study was to describe the pheasant semen collection method, evaluate some qualitative parameters of sperm from males fed an antioxidant-enriched diet, and to test the in vivo fertilising capacity of the cryo-preserved semen. The freezing protocol employed involved pellets thawed by the hotplate method. Dimethylacetamide was used as a cryoprotectant at a final concentration of 6%. A total of six AIs were performed at 3-4-day intervals on a total of 40 females with doses of 35 × 106 of normal live thawed sperm. Males receiving the enriched diet produce more abundant and concentrated ejaculates. Freeze–thawed sperm lost 85% of their initial mobility, and diet influenced neither sperm mobility nor viability. The enriched diet did improve the number of normal freeze–thawed cells and was associated with a lower sperm fracture incidence. Regardless of the dietary group, frozen–thawed sperm resulted in a fertility rate of 30%, with 8-9 chicks hatching for every 100 eggs incubated.

In the current study, a macroscopic lattice Boltzmann model for simulating the heat and moisture transport phenomenon in unsaturated porous media during the freezing process was proposed. The proposed model adopted percolation threshold to reproduce the extra resistance in frozen fringe during the freezing process. The freezing process in Kanagawa sandy loam soil was demonstrated by the proposed model. The numerical result showed good agreement with the experimental result. The proposed model also offered higher computational efficiency and better agreement with the experimental result than the existing numerical models. Lattice Boltzmann method is suitable for simulating complex heat and mass transfer process in porous media at macroscopic scale under proper dimensionless criterion, which makes it a potentially powerful tool for engineering application.

The sperm of each avian species and breed have unique characteristics that render them more or less susceptible to the freezing–thawing process; therefore, a suitable cryopreservation protocol that is specific for the sperm of each type of bird is needed. In this context, little information about the common pheasant’s sperm is available. Therefore, the aim of this study was to test different parameters at each step of the process of freezing into pellets and thawing to detect the least deleterious parameter settings. Sixteen different protocols were tested by studying two levels in each of the four steps (dilution, equilibration at 5 °C, final dimethylacetamide concentration, and dimethylacetamide equilibration time) comprising the freezing process. The pheasant sperm exhibited a high susceptibility to the damage caused by freezing into pellets; however, the survival of the sperm reached 29%, and the greatest recovered mobility was 22%. The mobility of the sperm was affected by the dilution and the dimethylacetamide concentration, and the viability of the sperm was affected by the equilibration at 5 °C and the dimethylacetamide equilibration. The protocols that caused the least damage to the pheasant sperm were found to be those with higher dilution rates, 10 min of equilibration at 5 °C, and 6% dimethylacetamide equilibrated for 1 or 5 min. In the present study, we individualise some applicable parameters for certain critical steps of the freezing–thawing process; however, further investigations are needed in order to improve upon and complete a suitable protocol for the cryopreservation and thawing of pheasant sperm.

In this paper, we investigate the self-propelled particles confined on a spherical substrate and explore the structural and dynamic properties of self-propelled particles by controlling the packing fraction and activity. We find that these self-propelled particles freeze into the crystal with the increase in the packing fraction. We observe the pattern evolution of inevitable topological defects due to the geometric constraints of the spherical substrate. During the process of freezing, there is a transition from twelve isolated grain boundaries to the uniform distribution of defects with the increase in the self-propelled velocity. Finally, we establish a phase diagram of the freezing process. These results may deepen our understanding of active particles in complex and crowded environments. [ABSTRACT FROM AUTHOR]

In cold regions, frozen soil is common and causes various forms of frost damage to engineering projects, particularly canals constructed in seasonally frozen ground. The freezing and frost heave processes are complicated, involving heat transfer, water migration, water–ice phase change, ice accumulation and frost heave deformation. To study the frost heave mechanism of cold-region canals, a centrifuge model of a canal in a freezing environment was constructed and used to simulate canal temperature, water and deformation changes. The experimental and numerical results show that the canal temperature decreases rapidly, forming a substantial temperature gradient in the ground. Driven by the temperature gradient, a portion of the pore water migrates, while other pore water in the freezing zone becomes ice. These phenomena are responsible for the frost heave deformation of the canal model. Generally, the vertical displacement at the top of the canal and the horizontal deformation in the middle-low part of the canal slope are larger than those in other zones, and frost damages occur more easily in these zones. Therefore, to ensure safe operation, these zones should be closely monitored. This study is expected to help the engineer understand the frost heave mechanism of cold-region canals and to design a scientific anti-frost canal. Additionally, the centrifuge and numerical models and results in this study may serve as references for further research. [ABSTRACT FROM AUTHOR]

Many countries in the world are experiencing a severe water crisis with 1.1 billion people living without access to clean and safe drinking water. Fluoride is ubiquitous in nature and an excessive intake of fluoride via the drinking water results in significant health effects, particularly with exposure in utero and in early childhood. Most of the conventional methods for the removal of fluoride from drinking water in water treatment plants require high initial capital and ongoing maintenance costs. The aim of the present study was to investigate the freezing and melting process as an innovative, convenient, and low-cost technology to produce healthy drinking water for people living in areas with high drinking water fluoride concentrations. We found that the freezing and melting process had a proximate fluoride removal performance of 60% when the freezing of water with a high concentration of fluoride proceeded until 10-15% of the initial water volume was frozen. Nevertheless, in order to achieve drinking water with less than 1.5 mg/L of fluoride, from water with a high initial fluoride content, one or two re-freezing steps of the melted ice were required. In the end, it was proven that this method is able to produce enough healthy drinking water for children for households. This process could be used as a cost-effective large scale technology in the community or as a small scale method at home with a minimal capital expenditure and no need for advanced knowledge requirements. With application of liquid natural gas (LNG), solar energy, and wind power as clean and cheap energy sources, it will be possible to build large scale freezing systems for the removal of fluoride from drinking water for communities. [ABSTRACT FROM AUTHOR]

Highlights • Impact freezing for water droplets supercooled deeply is carried out. • The nucleation in different dynamic phases has a significant influence on the final freezing morphology. • There are multiple freezing morphologies under constant conditions due to the uncertain nucleation time. • The relationship between freezing morphology and freezing type is proposed. • Three kinds of impact freezing process for room temperature water droplets are observed. Abstract The freezing morphologies and types for droplets at supercooled (−15 °C) and room temperature (20 °C) to impact onto a cold and polished aluminum substrate are investigated experimentally in this paper. It is found that the nucleation in different dynamic processes has a significant effect on the final freezing morphology and there are multiple freezing morphologies under constant conditions due to the uncertain nucleation time. Thus, based on the final freezing shapes, a basic classification for the different freezing morphologies is presented in terms of basin, pancake and semisphere; and three corresponding freezing types, including instantaneous freezing, non-instantaneous freezing and quasi-static freezing, are proposed based on the nucleation in distinct dynamic phases. Furthermore, the relative number of nucleation drops is taken as a function of time, and then the probability of various freezing morphologies and types in each experimental condition is provided. As a result, for both of the supercooled and room temperature water droplets, although the relative number of nucleation drops have roughly the same variational tendency for impact freezing, the nucleation time and the probability of various freezing morphologies remain different, for example, no basin shapes were attained in the case of room temperature water droplets under the experimental conditions of the current study. Meanwhile, the experimental results show that there are obvious diversities on freezing process. Three kinds of freezing processes, including traditional supercooled water freezing process, are presented for the impact freezing of room temperature droplets, which is mainly determined by the nucleation time. Therefore, for further studies of ice formation, the present results suggest that not only the effect of kinetics and heat transfer but also the influence of the nucleation time should be considered, particularly for the large droplets supercooled deeply. [ABSTRACT FROM AUTHOR]

• The relationship between magnetic field intensity and frost suppression effect is not linear. • As the temperature of the cold surface decreases, the suppressing freezing ability of the magnetic field becomes worse. • The initial freezing time of the droplet decreases as its volume increases from 20 μL to 50 μL. In this study, the effect of magnetic field on droplet freezing was investigated based on a visualization system. Possible influencing factors on droplet freezing, such as magnetic field intensity, cold surface temperature, and droplet volume, were considered in this study. During the two stages of droplet supercooling and freezing process, the changes of the droplet internal temperature, the formation of initial crystal nucleus, and the freezing time were observed. Experimental results show that in comparison with the non-magnetic surface, the supercooling degree of droplets was increased in the range of 150–300 mT magnetic field intensity, thereby prolonging the freezing time of droplets. Particularly, the droplet was best suppressed on a cold surface with 250 mT magnetic field intensity. The freezing time of droplets was prolonged by 132.0 %. However, the droplets were accelerated to freeze on the cold surface with magnetic field intensities of 350 mT and 400 mT. Droplet freezing on cold surfaces was also affected by surface temperature and droplet volume. As the surface temperature of magnetic cooling dropped from −10 °C to −20 °C, the ability of the magnetic field to inhibit droplet freezing would be gradually weakened. With the increase of droplet volume from 20 μL to 50 μL, the initial freezing time of droplets was shortened. These results are related to the influence of magnetic field on the nucleation process and hydrogen bond in the water molecular cluster. [ABSTRACT FROM AUTHOR]

• The S cr of GIC-0, GIC-50 and GIC-100 are about 76–78%, 84–86% and 89–91%. • When S > S cr, the supercooling phenomenon of the adsorbed water is obvious. • S < Scr specimens have virtually no hysteresis curves during freeze–thaw cycles. • Saturation(S) and GHBs content affect the freezing process of water in concrete. • S and GHBs content affect pore size distribution during concrete freezing. This paper uses experimental analysis to understand the freezing law of water to determine the freezing damage mechanism of Glazed Hollow Bead Insulation Concrete (GIC). The critical saturations of GIC with different Glazed Hollow Beads (GHBs) contents were obtained by the relative moving modulus after testing seven saturations of the concrete (70% to 100%, 5% interval). The critical saturation of GIC-0 (i.e., 0% GHBs content) occurred at ∼ 76–78%. GIC-50 occurred at about 86–88%. GIC-100 occurred at about 89–91%. GIC-0, GIC-50, and GIC-100 were then saturated to S 60 , S cr , and S 100 based on their respective critical saturation. Low-field nuclear magnetic resonance (NMR) was used to study the freezing process of different water types in GIC. The results showed that: 1) The water inside GIC was composed of adsorb water, pore water, and free water; 2) The whole freezing process could be roughly divided into four stages: subcooling stage, rapid freezing stage, stable freezing stage, and the end of the freezing phase; 3) During the freezing and thawing process, the change in unfrozen water content of GIC specimens had a hysteresis curve, while the specimens less than the critical saturation had almost no hysteresis curve. Moreover, the saturation significantly influenced the freezing process of different water types, which determined the proportion of them. This study also determined the evolution of the pore size of GIC, which provides a new idea for analyzing the freezing damage mechanism of porous GIC. [ABSTRACT FROM AUTHOR]

There is a widely held belief that the semen of Purebred Spanish Horses (PRE) is of generally poorer quality than that of other breeds, and survives cryopreservation less well. To determine whether this is the case, sperm concentration, viability and morphological abnormalities were examined in a total 610 fresh ejaculates from 64 healthy PRE (N=47) and non-PRE stallions (N=17). Sperm concentration and viability were then re-examined after pre-freezing centrifugation, and once again after freezing-thawing. No differences were observed between the PRE and non-PRE stallions in terms of any sperm quality variable at any observation point. When considering all PRE and non-PRE samples together, differences in sperm viability were observed between fresh and fresh-centrifuged sperm viability (70.1±12.5% compared to 76.3±10.9%; p

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Nowadays a considerable number of people all around the world are affected by severe water scarcity. Nitrate and nitrite are widespread in the environment. Nitrate is the most common chemical contaminant in the world’s groundwater aquifers. Conventional water treatment processes used at municipal water treatment plants such as coagulation, sedimentation, filtration, and chlorination, and even some of the most common tertiary processes like adsorption are not effective for nitrate removal. Among the novel techniques for nitrogen removal from aqueous solutions, the freezing-melting process is of the most convenient and effortless especially for a nonexpert person. The main objective of this study was to evaluate the performance of nitrate removal from aqueous solutions through freezing- melting process. Eight different nitrate concentrations ranged from 50 up to 250 mg/L were used in this study. Nitrate content of these solutions was reduced to its drinking water standard just by a single run or right after the first repetition of the process. [ABSTRACT FROM AUTHOR]

Complex coacervate from whey protein isolate (WPI)- Saccharomyces cerevisiae (Y) was prepared for microencapsulation by spray-drying. The optimum WPI-Y complex coacervate reached the best interaction for a ratio and pH of 1:13 and 3.28, respectively. The complex coacervate was spray-dried with 10% and 20% w/w of total solids content using maltodextrin DE10 (MD) as wall material and subsequently frozen at −18 °C. DSC, FTIR and SEM analyses were carried out to characterize thermal, chemical and structural properties of pure materials and spray-dried WPI-Y complex coacervates. Thermograms of DSC reflected that the spray-dried WPI-Y complex coacervates were better protected when MD concentration increased because the denaturation peak temperature of proteins and enthalpy were higher. These results were confirmed with FTIR analysis since peaks intensity of amino groups was highest in the spray-dried WPI-Y complex coacervate containing 20% w/w of total solids content. After the freezing process, reduced decrease in the peaks intensity of the amides in the spray-dried WPI-Y complex coacervate with 20% w/w of total solids content was observed. Morphology of all spray-dried complex coacervates exhibited particles of spherical shapes with concavities, dents and hollows in the center. However, particles after the freezing process displayed fractures in the surface. Finally, yeast survival was higher in the spray-dried WPI-Y complex coacervate with higher concentration of MD and as well after freezing process. Therefore, WPI-Y complex coacervates were stable after freezing process and can be used to stabilize fermentative microorganisms in order to produce frozen dough with similar characteristics that the dough. [ABSTRACT FROM AUTHOR]

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

The winter operation of all-glass evacuated tube solar water heaters (ETSWH) often encounters the problem of ice damage. Studying their nighttime heat dissipation and freezing characteristics can further reduce the risk of frost damage during winter use. A numerical model for the nighttime heat dissipation of all-glass evacuated tube collectors is proposed in this study. An enthalpy equation is also introduced to analyze the heat dissipation process and freezing conditions of water inside the ETSWH under lower temperature conditions. Based on this, a nighttime heat loss model for solar vacuum tube collectors, including the effects of radiation and phase change factors, is established and validated through nighttime temperature drop experiments, which can effectively predict the temperature distribution and antifreeze performance of ETSWH during the nighttime heat dissipation process. In addition, the independent effects of the initial temperature of the water inside ETSWH, the thickness of the water tank insulation layer, and the absorptive coating emissivity on the heat dissipation process of ETSWH are studied, and the heat dissipation of ETSWH during winter nights in five different climatic zones in China is simulated. Experimental and simulation results show that under cold and clear winter weather conditions in Luoyang, ice forms in ETSWH during nighttime. The icing first occurs at the bottom of the vacuum tube, and the icing length on the wall and the icing thickness at the bottom can reach 1145 mm and 15 mm, respectively. In severely cold areas and cold regions such as Harbin and Beijing, there is a high risk of frost damage to ETSWH during winter. Keeping the initial working fluid temperature in the heater above 50 °C, ensuring a minimum insulation thickness of 50 mm, and reducing the emissivity of the absorptive coating in the heater to below 0.07 can effectively solve the freezing problem and have significant implications for the promotion and application of all-glass evacuated tube collectors. • The enthalpy equation of mathematical model was introduced to predict freezing of SWH. • The heat dissipation and freezing of ETSWH were analyzed by the mathematical model. • The mathematical model of the ETSWH was validated by experiments. • The performance of ETSWH under different climatic conditions in China was predicted. • Factors influencing the antifreeze performance of the collector were investigated. [ABSTRACT FROM AUTHOR]