Freezing Of Water Research Articles

Internal flow in freezing and non-freezing water droplets at freezing temperatures

By comparing freezing and non-freezing water droplets with Particle Image Velocimetry (PIV), this paper aims to further advance the knowledge of the internal movement in deposited water droplets. The experiments are carried out at substrate temperatures below 0 °C, and the onset of the freezing process is controlled by the structure of the plate. Results show similar flow patterns for the freezing and non-freezing case, indicating that the phase change is not the initial driving force of the internal movement or the directional change phenomena. The phase change will, however, decrease the volume of the liquid and generate a difference in heat transfer and temperature, hence introducing a faster decrease in velocity and sooner directional velocity change. In the non-freezing case, a stagnated period at the beginning of the internal movement is observed before the decrease in velocity.

Phase-Change Stamp with Highly Switchable Adhesion and Stiffness for Damage-Free Multiscale Transfer Printing.

Transfer printing is a technology widely used in the production of flexible electronics and vertically stacked devices, which involves the transfer of predefined electronic components from a rigid donor substrate to a receiver substrate with a stamp, potentially avoiding the limitations associated with lithographic processes. However, the stamps typically used in transfer printing have several limitations related to unwanted organic solvents, substantial loading, film damage, and inadequate adhesion switching ratios. This study introduces a thermally responsive phase-change stamp for efficient and damage-free transfer printing inspired by the adhesion properties observed during water freezing and ice melting. The stamp employs phase-change composites and simple fabrication protocols, providing robust initial adhesion strength and switchability. The underlying mechanism of switchable adhesion is investigated through experimental and numerical studies. Notably, the stamp eliminates the need for extra preload by spontaneously interlocking with the ink through in situ melting and crystallization. This minimizes ink damage and wrinkle formation during pickup while maintaining strong initial adhesion. During printing, the stamp exhibits a sufficiently weak adhesion state for reliable and consistent release, enabling multiscale, conformal, and damage-free transfer printing, ranging from nano- to wafer-scale. The fabrication of nanoscale short-channel transistors, epidermal electrodes, and human-machine interfaces highlights the potential of this technique in various emerging applications of nanoelectronics, nano optoelectronics, and soft bioelectronics.

Effect of wheat flour particle size on the quality deterioration of quick-frozen dumpling wrappers during freeze-thawed cycles

To reveal the effect of wheat flour particle size on the quality deterioration of quick-frozen dumpling wrappers (QFDW) during freeze-thawed (F/T) cycles, the components and physicochemical properties of wheat flours with five different particle sizes were determined and compared, along with the changes in texture and sensory properties, water status, and microstructure of QFDW during F/T cycles. Results showed that as particle size decreased, the damaged starch content and B-type starch content increased, the water absorption increased, and the gluten strength decreased. Furthermore, F/T cycles negatively impacted the quality of QFDW, evidenced by decreased texture properties and sensory evaluation score, water redistribution, higher freezable water content, and disruption of gluten network. Notably, QFDW made from larger particle size wheat flours required the shortest duration when traversing the maximum ice crystal formation zone. The QFDW made from larger particle size wheat flours formed a more stable starch-gluten matrix, which resisted the damage caused by ice recrystallization, demonstrating better water binding capacity and F/T resistance. The results may provide theoretical guidance for the study of QFDW quality and the moderate processing of wheat flour in actual production.

Experimental and numerical investigation of water freezing and thawing in fully saturated sand

Abstract This paper presents an experimental and numerical study of the freezing-thawing behavior of water in fully saturated sand. A relatively inexpensive and easily replicable experimental procedure was developed to simulate the freezing-thawing cycles in a medium-sized sand sample placed in a modified commercial freezer. By insulating the sides and bottom of the sample well, while allowing good thermal conductivity at the top of the sample, a nearly vertical advance of the freezing and thawing front was achieved. A series of freeze-thaw cycles were performed with higher and lower temperature gradients. A numerical multiphysics model, assuming an axially symmetric geometry based on the transient heat transfer during the phase transition, used a parametric approach to estimate the effective thermal properties of the sand-water-ice system. A good agreement between experimental and modelling results was shown, but slightly different parameter sets were obtained for each temperature gradient. The presented method could be a simple way to characterize the freeze-thaw process in natural and artificial porous materials.

Potential Reduction of Spatiotemporal Patterns of Water and Wind Erosion with Conservation Tillage in Northeast China

Conservational tillage (NT) is widely recognized globally for its efficacy in mitigating soil loss due to wind and water erosion. However, a systematic large-scale estimate of NT’s impact on soil loss reduction in Northeast, China’s primary granary, remains absent. This study aimed to investigate the spatial and temporal variability of soil erosion under NT compared to conventional tillage (CT) in the black soil region and to analyze the underlying mechanisms driving these erosions. The Revised Universal Soil Loss Equation (RUSLE) and the Revised Wind Erosion Equation (RWEQ) models were employed, incorporating previously published plot/watershed data to estimate the potential reduction of water and wind erosion by NT in this region. Results indicated that under CT practices, water- and wind-induced soil losses were widely distributed in the arable land of Northeast China, with intensities of 2603 t km−2 a−1 and 34 t km−2 a−1, respectively. Furthermore, the erosive processes of water and wind erosion were significantly reduced by 56.4% and 91.8%, respectively, under NT practices compared to CT. The highest efficiency in soil conservation using NT was observed in the mountainous regions such as the Changbai Mountains and Greater Khingan Mountains, where water erosion was primarily driven by cropland slopes and wind erosion was driven by the wind speed. Conversely, the largest areas of severe erosion were observed in the Songnen Plain, primarily due to the significant proportion of arable land in this region. In the plain regions, water-induced soil loss was primarily influenced by precipitation, with light and higher levels of erosion occurring more frequently on long gentle slopes (0–3°) than on higher slope areas (3–5°). In the temporal dimension, soil loss induced by water and wind erosion ceased during the winter under both tillage systems due to snow cover and water freezing in the soil combined with the extremely cold climate. Substantial reductions were observed under NT from spring to autumn compared to CT. Ultimately, the temporal and spatial variations of soil loss under CT and NT practices were established from 2010 to 2018 and then projected onto a cropland map of Northeast China. Based on this analysis, NT is recommended as most suitable practice in the southern regions of Northeast China for maintaining soil health and crop yield production, while its suitability decreases in the northern and eastern regions.

Effects of curdlan on the quality of frozen steamed bread: quality changes, water state and starch crystallinity

SummaryThe purpose of the study was to explore the effects of curdlan on the textural and sensory qualities of frozen steamed bread (FSB), as well as water state and starch properties during freezing. The results showed that incorporation of curdlan improved the springiness and resilience, while it reduced the hardness and chewiness of FSB. The quality deterioration of FSB was largely caused by the growth and recrystalisation of ice crystals. However, incorporation of curdlan mitigated this adverse impact by regulating water state. Specifically, it increased water content, inhibited water migration, and significantly decreased freezable water content. Additionally, curdlan also decreased starch relative crystallinity, which hindered its retrogradation and thus maintained the overall quality of FSB. Notably, inclusion of 0.5% curdlan exhibited optimal effectiveness in improving quality as evidenced by the highest sensory score obtained.

Contribution of yeast freezing to the quality of frozen dough: Rheological properties, protein depolymerization, gluten conformation and water state

The present study has comparatively investigated the variation in yeast leachates in frozen suspension and dough systems and assessed the effects of leachate released from frozen yeast cells on dough rheology, protein molecular weight distribution, gluten conformation, and water state. The results revealed that yeast in the dough was more susceptible to freezing than that in the suspension and released more low-molecular-weight metabolites (e.g., trehalose, glutathione, and amino acids) into the dough matrix. Dynamic rheological measurements showed that frozen yeasted dough had weaker viscoelastic properties than non-yeasted dough. Fourier transform infrared spectroscopy revealed a high fraction of β-turns and random coils at the expense of α-helices and β-sheets, demonstrating a flexible protein secondary structure and increase in weakened hydrogen bonds in the gluten network. The presence of yeast in the frozen dough facilitated dough depolymerization via the cleavage of interchain disulfide bonds of gluten protein and softened the gluten network structure. Yeast leachates released from frozen yeast cells caused water redistribution in the dough and increased water release from the weakened gluten network, increasing freezable water content. This study has revealed the essential role of yeast freezing in gluten depolymerization and the deterioration of dough quality.

Environmentally stable and rapidly polymerized tin-tannin catalytic system hydroxyethyl cellulose hydrogel for wireless wearable sensing

In recent years, flexible sensors constructed mainly from hydrogels have played an indispensable role in several fields. However, the traditional hydrogel preparation process involves complex and time-consuming steps and the freezing or volatilization of water in the water gel in extreme environments greatly limits the further use of the sensor. Therefore, an ionic conductive hydrogel (SnHTD) was designed, which was composed of tannic acid (TA), metal ions Sn2+, hydroxyethyl cellulose (HEC), and acrylamide (AM) in a deep eutectic solvent (DES) and water binary solvent. It is worth noting that the gel time is shortened to less than 3 min by introducing the Sn-TA redox system. The addition of DES makes the hydrogel have a wide temperature tolerance range (−20 to 60 °C) and the ability to store for a long time (30 days). The introduction of HEC increased the tensile stress of hydrogel from 140.17 kPa to 219.89 kPa. Additionally, the hydrogel also has high conductivity, repeatable adhesion and UV shielding properties. In general, this research opens up a new way for room temperature polymerization of environmentally resistant hydrogel materials and effectively meets the growing demand for wireless wearable sensing.

Peptide incorporation in frozen dough and steamed bread: Characteristics and structure-function relationship

Antarctic krill peptide (AKP), a bioactive compound, has garnered significant attention in recent years. This study aimed to explore the effects of varying levels of AKP addition (ranging from 0% to 2.0%, based on the flour, w/w) and different freezing time (0, 1, 2, 4, and 6 weeks) on the rheological properties, rheo-fermentation properties, water distribution, and microstructure of dough. The results revealed that the addition of AKP led to a reduction in the freezable water content, T2 relaxation time, and free sulfhydryl content of frozen dough. After 6 weeks of freezing, the viscoelastic properties of the dough with AKP were higher than those of the control. Additionally, the fermentation height of dough containing 1.5% AKP increased by 25.85% compared with the control, resulting in increased springiness and specific volume, and decreased hardness in the resulting steamed bread. Pearson correlation analysis showed a positive correlation between freezable water content and free sulfhydryl groups, while a negative correlation was observed with springiness. Furthermore, springiness showed a positive correlation with the DPPH free radical scavenging rate. These findings highlight the potential of AKP as a novel food cryoprotectant capable of significantly enhancing the quality and nutritional value of frozen wheat products.

Mpemba effect in pure spin systems : A universal picture of the role of spatial correlations at initial states.

The quicker freezing of hotter water, than a colder sample, when quenched to a common lower temperature, is referred to as the Mpemba effect (ME). While this counter-intuitive fact remains a surprize since long, efforts have begun to identify similar effect in other systems. We investigate the ME in a rather general context concerning magnetic phase transitions. From Monte Carlo simulations of model systems, viz., the Ising model and the q-state Potts model, with varying range of interaction and space dimension, we assert that hotter paramagnets undergo ferromagnetic ordering faster than the colder ones. This conclusion we have arrived at following the analyses of the simulation results on decay of energy and growth in ordering following quenches from different starting temperatures, to fixed final temperatures below the Curie points. The general observation, in all the considered models, without any element of frustration, is a crucial and important fact of our study. Furthermore, we have obtained an important scaling picture, on the strength of the effect, with respect to the variation in spatial correlation in the initial states. This behavior appears true irrespective of the nature of order-parameter fluctuation and even order of transition. The observations are expected to be relevant to the understanding of ME in a rather general class of systems.

Liquid-free, tough and transparent ionic conductive elastomers based on nanocellulose for multi-functional sensors and triboelectric nanogenerators

Stretchable and transparent ionic conductors have attracted great interest due to their promising applications in flexible wearable electronics. The obvious drawbacks of gel-based ionic conductors such as hydrogels (e.g., evaporation or freezing of water) have driven the demand for liquid-free ionic conductors. This paper reports a new strategy for fabricating transparent, liquid-free ionic conductive elastomers based on renewable nanocellulose. A three-dimensional cellulose skeleton was constructed through ionic cross-linking, and the physically and chemically cross-linked dual network structure was prepared by in situ polymerization of the polymerizable deep eutectic solvent (PDES) therein. The homogeneous three-dimensional cross-linked network provides a site for energy dissipation and ionic migration. Results show that the elastomers retain good transparency and achieve significantly improved mechanical strength, toughness and ionic conductivity. Therefore, they can be applied as multi-functional sensors and triboelectric nanogenerators (TENG). For the optimized TENG, output voltage, current and charge reach 115 V, 6 μA, and 40 nC, respectively. A maximum output power density of 0.35 W/m2 is achieved, and the collected mechanical energy can light up LEDs and power an electronic clock. In addition, the elastomers maintain reliable performance even at low/high temperatures, enabling use in harsh environments. In conclusion, this study developed a promising strategy for the construction of sustainable liquid-free ionic conductors utilizing natural polysaccharides.

Assessment of water quality from different water supply sources in the Kyiv district of the city of Kharkiv

Purpose To evaluate the quality of drinking water from various sources of water supply on the example of the Kyiv district of the city of Kharkiv. Methods. Field (selection of water samples from various sources), laboratory-analytical analysis of water quality, statistical (processing of received data and comparative analysis). Results. Water samples were taken from various sources of water supply: natural spring water, water from wells, from a well, from the city water supply and from drinking water dispensers. In the samples of artesian water of the "Roganska" trade mark (automatic water dispenser), no exceeding of the normative values ​​was determined for any indicator. Water samples from wells and centralized water supply have elevated levels of total hardness, chlorine, nitrate and iron content, which requires the restriction of their use as drinking water without additional treatment. Water samples from private wells have an increased level of general mineralization, salinity and electrical conductivity of water. Methods of purifying tap water from common salts at home were studied: water freezing, filtration, settling, boiling. Conclusions. On the basis of organoleptic, physico-chemical and toxicological parameters of water quality, according to DSTU 4808, water from the machine of TM "Roganska" corresponds to the 1st quality class, spring water - 2nd class, water from wells - 3rd class, and water from a well and centralized water supply - 4th class. In order to improve the quality of tap water from common salts at home, freezing and filtration are recommended.

Effects of Lime Powder on the Properties of Portland Cement-Sulphoaluminate Cement Composite System at Low Temperature.

In order to reduce the risk of early freezing damage to cement-based materials in winter construction, lime powder was used to improve the properties of the Portland cement-sulphoaluminate cement (PC-CSA) composite system at low temperatures. In this study, the effects of lime powder dosage on the properties of a PC-CSA blended system with two proportions (PC:CSA = 9:1 and 7:3) at -10 °C were investigated, and the mechanisms of improvement were revealed. The results showed that the compressive strength of the PC-CSA composite system was effectively improved, and the setting time was shortened by the addition of lime powder. Lime powder could effectively act as an early heating source in the PC-CSA composite system, as the maximum temperature of samples exposed to sub-zero temperatures was increased and the time before dropping to 0 °C was prolonged by the addition of lime powder. The extra CH generated by the hydration of lime powder provided an added hydration path for C4A3S¯, which accelerated the formation of AFt at each stage. Frozen water as well as the early frost damage were effectively decreased by lime powder because of the faster consumption of free water at an early stage. The modification of the hydration products also contributed to the denseness of the microstructure.

Frozen water on Earth

Frozen water on Earth

Freezing rate's impact on starch retrogradation, ice recrystallization, and quality of water-added and water-free quick-frozen rice noodles

The study evaluated the effect of freezing rate on the quality of water-added quick-frozen rice noodles and water-free quick-frozen rice noodles. Results indicated that the retrogradation enthalpy, relative crystallinity, freezable water content, and cooking loss of water-added quick-frozen rice noodles were higher than those of water-free quick-frozen rice noodles with increasing storage time. Furthermore, ice recrystallization accelerated the deterioration of the quality of the rice noodles, resulting in the enlargement of the pores within the rice noodles and the formation of many pores on the surface. This phenomenon was particularly evident in the rice noodles of Y-40 °C (freezing with water at −40 °C) and Y-60 °C (freezing with water at −60 °C). After 28 days of frozen storage, the hardness increased by 83.83 % for rice noodles of Y-20 °C (freezing with water at −20 °C), while the hardness decreased by 51.68 % and 45.80 %, respectively, for rice noodles of Y-40 °C and Y-60 °C. Consequently, the impact of the freezing rate on the quality of water-added quick-frozen rice noodles is more pronounced than that of water-free quick-frozen rice noodles. Moreover, a higher freezing rate can delay the deterioration of the quality of frozen rice noodles by postponing starch retrogradation and inhibiting ice recrystallization.

Effect of water cooling treatment on structure and cooking characteristics of frozen extruded whole buckwheat noodles

SummaryThe effect of 4 °C water cooling treatment after extrusion for different time (0 s, 30 s, 1 min, 3 min, and 5 min) on the structure and cooking characteristics of frozen extruded whole buckwheat noodles were investigated. The cooking time and cooking loss of frozen extruded whole buckwheat noodles significantly decreased after water cooling, and the broken rate was kept constant at 0%, indicating that the quality of frozen noodles was significantly improved. When the time for water cooling was 30 s, the noodles had the lowest cooking loss of 4.07% and the highest hardness and springiness of 3993.19 g and 0.96, respectively. X‐ray diffraction results showed that water cooling treatment increased the crystallinity of starch, and the amylose underwent short‐term ageing. It was also observed from a scanning electron microscope that the gel network structure of the noodles treated with 30 s water cooling was more complete and uniform. Differential scanning calorimetry analysis showed that the water cooling treatment significantly increased the freezable water content. Meanwhile, low‐field nuclear magnetic resonance indicated that the water mobility in the noodles was weakened. The above results showed that 4 °C water cooling treatment for 30 s was beneficial to the formation of starch gel structure and improved the quality of frozen noodles. This study provides a new approach to improve the quality of extruded whole buckwheat noodles.

Effects of fish skin collagen peptide on physicochemical properties of frozen dough and quality and antioxidant activity of steamed bread

Fish skin collagen peptide (FSCP), as a bioactive peptide, holds significant potential in the food industry, particularly in enhancing the quality and nutritional attributes of frozen dough products. This research examined the impacts of FSCP addition and freezing time on water distribution, rheo-fermentation, rheological, and structural properties of dough, as well as the textural properties, internal structure, and antioxidant activity of steamed bread. The results showed that adding FSCP inhibited water migration and reduced freezable water content. After 4 weeks of freezing, the freezable water content of the FSCP-added groups decreased by 0.42%–4.77% compared with the control. Rheo-fermentation analysis indicated that the total CO2 release volume, maximum dough development height, and CO2 retention volume initially increased with FSCP concentration, peaking at 1.5%, before decreasing with further increases in FSCP concentration. Moreover, FSCP effectively mitigated gluten freeze damage, resulting in a slower decline in disulfide bond content and viscoelasticity. Additionally, it improved the textural properties and antioxidant activity of the steamed bread. X-ray micro-CT images revealed that FSCP improved gas pore distribution and network density in the steamed bread. Overall, FSCP proved effective in improving the attributes of frozen dough and the final steamed bread, particularly at a 1.5% concentration. These findings suggest a promising application of FSCP in frozen dough-based products, especially in the development of functional foods.

Quantitative Analysis of the Synergy of Doping and Nanostructuring of Oxide Photocatalysts.

In this paper, the effect of doping and nanostructuring on the electrostatic potential across the electrochemical interface between a transition metal oxide and a water electrolyte is investigated by means of the Poisson-Boltzmann model. For spherical nanoparticles and nanorods, compact expressions for the limiting potentials at which the space charge layer includes the whole semiconductor are reported. We provide a quantitative analysis of the distribution of the potential drop between the solid and the liquid and show that the relative importance changes with doping. It is usually assumed that high doping improves charge dynamics in the semiconductor but reduces the width of the space charge layer. However, nanostructuring counterbalances the latter negative effect; we show quantitatively that in highly doped nanoparticles the space charge layer can occupy a similar volume fraction as in low-doped microparticles. Moreover, as shown by some recent experiments, under conditions of high doping the electric fields in the Helmholtz layer can be as high as 100 mV/Å, comparable to electric fields inducing freezing in water. This work provides a systematic quantitative framework for understanding the effects of doping and nanostructuring on electrochemical interfaces, and suggests that it is necessary to better characterize the interface at the atomistic level.

Complex dynamics of partially freezable confined water revealed by combined experimental and computational studies

We investigate water dynamics in mesoporous silica across partial crystallization by combining broadband dielectric spectroscopy (BDS), nuclear magnetic resonance (NMR), and molecular dynamics simulations (MDS). Exploiting the fact that not only BDS but also NMR field-cycling relaxometry and stimulated-echo experiments provide access to dynamical susceptibilities in broad frequency and temperature ranges, we study both the fully liquid state above the melting point Tm and the dynamics of coexisting water and ice phases below this temperature. It is found that partial crystallization leads to a change in the temperature dependence of rotational correlation times τ, which occurs in addition to previously reported dynamical crossovers of confined water and depends on the pore diameter. Furthermore, we observe that dynamical susceptibilities of water are strongly asymmetric in the fully liquid state, whereas they are much broader and nearly symmetric in the partially frozen state. Finally, water in the nonfreezable interfacial layer below Tm does not exhibit a much debated dynamical crossover at ∼220 K. We argue that its dynamics is governed by a static energy landscape, which results from the interaction with the bordering silica and ice surfaces and features a Gaussian-like barrier distribution. Consistently, our MDS analysis of the motional mechanism reveals a hopping motion of water in thin interfacial layers. The rotational correlation times of the confined ice phases follow Arrhenius laws. While the values of τ depend on the pore diameter, freezable water in various types of confinements and mixtures shows similar activation energies of Ea ≈ 0.43 eV.

Mapping “Brain Terrain” Regions on Mars Using Deep Learning

One of the main objectives of the Mars Exploration Program is to search for evidence of past or current life on the planet. To achieve this, Mars exploration has been focusing on regions that may have liquid or frozen water. A set of critical areas may have seen cycles of ice thawing in the relatively recent past in response to periodic changes in the obliquity of Mars. In this work, we use convolutional neural networks to detect surface regions containing “brain terrain,” a landform on Mars whose similarity in morphology and scale to sorted stone circles on Earth suggests that it may have formed as a consequence of freeze/thaw cycles. We use large images (∼100–1000 megapixels) from the Mars Reconnaissance Orbiter to search for these landforms at resolutions close to a few tens of centimeters per pixel (∼25–50 cm). Over 58,000 images (∼28 TB) were searched (∼5% of the Martian surface), and we found detections in 201 images. To expedite the processing, we leverage a classifier network (prior to segmentation) in the Fourier domain that can take advantage of JPEG compression by leveraging blocks of coefficients from a discrete cosine transform in lieu of decoding the entire image at the full spatial resolution. The hybrid pipeline approach maintains ∼93% accuracy while cutting down on ∼95% of the total processing time compared to running the segmentation network at the full resolution on every image.