Ice Structure Research Articles

Disordered Structure in Ice VII Observed by Neutron Technique

Disordered Structure in Ice VII Observed by Neutron Technique

Confining He Atoms in Diverse Ice-Phases: Examining the Stability of He Hydrate Crystals through DFT Approaches.

In the realm of solid water hydrostructures, helium atoms have a tendency to occupy the interstitial spaces formed within the crystal lattice of ice structures. The primary objective of this study is to examine the stability of various ice crystals when influenced by the presence of He atoms. Presenting a first attempt at a detailed computational description of the whole energy components (guest-water, water-water, guest-guest) in the complete crystal unit cells contributes to enhancing the knowledge available about these relatively unexplored helium-water systems, which could potentially benefit future experiments. For this purpose, two different ice structures were considered: the previously established He@ice II system, and the predicted (but currently nonexistent) He@ice XVII system. One of the main features of these He-filled structures is the stability conferred by the weak van der Waals dispersion forces that occur between the host lattice and the guest atoms, in addition to the hydrogen bonds established among the water molecules. Hence, it is crucial to accurately describe these interactions. Therefore, the first part of this research is devoted examining the performance and accuracy of various semi-local and non-local DFT/DFT-D functionals, in comparison with previous experimental and/or high-level computational data. Once the best-performing DFT functional has been identified, the stability of these empty and He-filled structures, including different number of He atoms within the lattices, is analysed in terms of their structural (lattice deformation), mechanical (pressure compression effects) and energetic properties (binding and saturation energies). In this manner, the potential formation of these structures under zero temperature and pressure conditions can be evaluated, while their maximum storage capacity is also determined. The obtained results reveal that, despite the weak underlying interactions, the He encapsulation has a rather notable effect on both lattice parameters and energetics, and therefore, the guest-host interactions are far from being negligible. Besides, both ice crystals are predicted to remain stable when filled with He atoms, with ice XVII exhibiting a higher capacity for accommodating a larger number of guest atoms within its interstitial spaces.

Stieltjes functions and spectral analysis in the physics of sea ice

Abstract. Polar sea ice is a critical component of Earth’s climate system. As a material, it is a multiscale composite of pure ice with temperature-dependent millimeter-scale brine inclusions, and centimeter-scale polycrystalline microstructure which is largely determined by how the ice was formed. The surface layer of the polar oceans can be viewed as a granular composite of ice floes in a sea water host, with floe sizes ranging from centimeters to tens of kilometers. A principal challenge in modeling sea ice and its role in climate is how to use information on smaller-scale structures to find the effective or homogenized properties on larger scales relevant to process studies and coarse-grained climate models. That is, how do you predict macroscopic behavior from microscopic laws, like in statistical mechanics and solid state physics? Also of great interest in climate science is the inverse problem of recovering parameters controlling small-scale processes from large-scale observations. Motivated by sea ice remote sensing, the analytic continuation method for obtaining rigorous bounds on the homogenized coefficients of two-phase composites was applied to the complex permittivity of sea ice, which is a Stieltjes function of the ratio of the permittivities of ice and brine. Integral representations for the effective parameters distill the complexities of the composite microgeometry into the spectral properties of a self-adjoint operator like the Hamiltonian in quantum physics. These techniques have been extended to polycrystalline materials, advection diffusion processes, and ocean waves in the sea ice cover. Here we discuss this powerful approach in homogenization, highlighting the spectral representations and resolvent structure of the fields that are shared by the two-component theory and its extensions. Spectral analysis of sea ice structures leads to a random matrix theory picture of percolation processes in composites, establishing parallels to Anderson localization and semiconductor physics and providing new insights into the physics of sea ice.

A temperature study of methanol interstellar ice analogues

Methanol ice has been studied in the field of astrochemistry for many years. As a simple organic compound, CH3OH is extremely interesting in the study of ice formation and evolution. There are three forms of methanol ice – amorphous, α-crystalline, and β-crystalline. Although there are studies focused on the comparison of crystalline and amorphous phases in terms of chemical properties, there is a lack of systematic studies on phase transition. Factors such as pressure, temperature, and rate of ice formation have an influence on the process of phase transition. In this study, the influence of temperature on the vibrational properties of methanol ice is considered. For the experimental section, a Portable Astrochemistry Chamber (PAC) with the ability to control deposition pressure and temperature was used. The temperature of phase transition was experimentally determined at 103 K and for analysis of the ice structure, two vibrational modes were chosen – OH stretch and CH3 in-plane rocking. Moreover, depositions at higher temperatures were performed with the result of different vibrational properties depending on ice formation conditions. This study presents the temperature-dependant properties of methanol ice in the mid-infrared spectrum and considers the possibility of thermal history determination.

The effect of magnetic and electric fields on the processes of food freezing

The article summarizes the results of studies based on scientific publications on the effect of magnetic fields (MF) and electric fields (EF) on the kinetics of freezing processes applied onto biological tissue and on their properties. The processes of freezing food media on installations equipped with the Cells Alive System (CAS) magnetic system manufactured by ABI Co., Ltd., Japan are considered in this article. It is shown that the majority of researchers did not confirm the benefits claimed by the CAS system developers in comparison with the processes of fast freezing in the chambers without the magnetic field. In the case of using the alternating magnetic fields (AMF) with high field induction values, the effect is more pronounced. The application of strong static or alternating EF contributes to the creation of a fine-grained structure of ice, reduces the freezing duration and decreases mass loss during the food thawing.

Acoustic transmission loss observed on a tomographic array in the Beaufort Gyre during 2016–2017

The Arctic Ocean is undergoing dramatic changes. The 2016–2017 Canada Basin Acoustic Propagation Experiment (CANAPE) was conducted to assess the effects of the changes in the sea ice and ocean structure in the Beaufort Gyre on low-frequency underwater acoustic propagation and ambient sound. An ocean acoustic tomography array with a radius of 150 km that consisted of six transceivers and a long vertical receiving array measured the impulse responses of the ocean every four hours using broadband signals with center frequencies that ranged from 172.5 to 275 Hz. Ice-profiling sonar data showed a gradual increase in ice draft over the winter with daily median ice drafts reaching maxima of about 1.5 m, suggesting that the ice was first-year ice. The transmission loss of early, resolved ray arrivals from steep ray paths with lower turning depths below 500 m was lowest when open water was present and increased as the ice draft increased. The transmission loss per surface reflection increased with center frequency and surface grazing angle. The values are greater than observed during the 1988–1989 Greenland Sea Tomography experiment, but the ice conditions likely differed significantly.

Puckered Zigzag Monolayer Ice: Does a Confined Flat Four-Coordinated Monolayer Ice Always Have a Corresponding Puckered Phase?

We note that a flat, four-coordinated monolayer ice under confinement always has a corresponding puckered phase. Recently, a monolayer ice consisting of an array of zigzag water chains (ZZMI) predicted by first-principles calculations of water under confinement is a flat four-coordinated monolayer ice. Herein, to investigate whether puckered ZZMI exists stably, we perform molecular dynamics simulations of two-dimensional (2D) ice formation for water constrained in graphene nanocapillaries. We find a novel monolayer ice structure that can be viewed as the ZZMI puckered along the direction perpendicular to the zigzag chain (pZZMI). Unlike ZZMI that does not satisfy the ice rule, each water molecule in pZZMI can form four hydrogen bonds (HBs) via forming two stable intersublayer HBs and two intrasublayer HBs. This work provides a fresh perspective on 2D confined ice, highlighting the intrinsic connections between 2D confined ices.

Investigating the Ice-Induced Fatigue Damage of Offshore Structures by Field Observations

The oil and natural gas resources of the Bohai Sea are mainly marginal oil fields, and there are currently a large number of structures that are approaching or have reached the end of their service life called aging structures. The interactions between ice and offshore structures could lead to significant ice-induced vibration. Ice-induced vibrations may evoke fatigue damage in tubular joints, which results in severe dangers for offshore platforms in the Bohai Sea. Dynamic ice force models and sea ice fatigue environmental parameters have not been well developed in the current design codes. It is not accurate to evaluate the fatigue damage of structures only with numerical simulation. In this paper, a faster method for evaluating fatigue damage on aging structures is proposed. Firstly, the approximate linear relationship between the fatigue hot spot stress and the vibration response of the deck structure has been discovered using dynamic analysis for jacket platform of Bohai Sea. Then, the procedure of the fatigue damage evaluation of the aging structures in the Bohai Sea is established. Finally, the numerical simulation of the structure is carried out considering ice thickness, ice velocity, ice direction, and action height of sea ice. Fatigue damage is calculated by the fatigue hot spot stress and the Palmgren–Miner rule. The measured data on the platform in the Bohai Sea are selected to obtain the fatigue hot spot stress using a mathematical model. The fatigue damage results considering the actual ice conditions of a jacket structure in the Bohai Sea are compared using the proposed method and finite element analysis. The comparison of the results verifies the rationality of the method proposed in this work.

Distribution and dynamics of water in the blended pastes unraveled by thermoporometry and dielectric properties

Water distribution in hardened paste and its dynamics determine many properties related to durability. Moisture distribution was determined by thermoporometry combined with vacuum drying. Dynamics of confined water were measured by broadband dielectric spectroscopy. Water in pores <2.4 nm cannot form tetrahedral ice structure due to geometrical constraints. The volume of unfrozen water (in interlayer and gel pores) decreases after the drying at all relative humidity levels. An evident coarsening of gel pores occurs with drying between 75 % and 55 % RH. 35 % fly ash and slag have limited effects on relaxation processes of silanol hydroxyl groups and interlayer water. However, they slow down the dynamics of water in small gel pores, thereby enhancing interactions between water and the solid interface. This study clarifies the microstructural changes during the drying and reveals the sensitivity of water dynamics to the chemical environment in C-S-H of blended pastes.

Ice structures assembled from cubic water clusters of D2d and S4 symmetry.

The study of self-assembly processes is of key importance for fundamental science and modern technologies. Cubic water clusters of D2d and S4 symmetry show great potential as building blocks for self-assembly. The objective of this paper is to construct possible ice structures formed by hydrogen bonding of these very stable water clusters. A number of such structures are herein presented, including quasi-2D and 3D ices as well as spatial layered and tubular ices. The energetics and structure of many configurations differing in the arrangement of hydrogen atoms in hydrogen bonds have been studied. It was established that the proton disorder of all such ices is of island type. The residual entropy of these ices is equal to ln(3)/4 in dimensionless form. For layered structures formed by the stacking of multiple bilayers, the determining role of the van der Waals interactions is shown. Note that, for all considered ices, the lowest-energy configurations are formed only by clusters of D2d symmetry.

Experimental Evaluation and Validation of Pressure Distributions in Ice–Structure Collisions Using a Pendulum Apparatus

This study introduced an experimental setup designed to predict collision pressure exerted on a structure due to ice impacts. The primary aim was to forecast the pressure distribution and structural behavior following an ice collision on a laboratory scale. The apparatus comprises a double-pendulum system situated within a cold chamber, facilitating the prediction of collision forces by varying both the collision energy and velocity. Experiments were conducted at collision velocities of 5, 7, and 10 knots, representative of conditions in Arctic regions. By altering these velocities, we measured both the strain experienced by a steel plate and the pressure due to the ice collision. The pressure distribution on the steel plate surface was also recorded by using pressure-sensitive film. This setup effectively captured the pressure distribution across the collision contact area. The measured pressure and force were compared with that of previous studies to determine the validity of the ice collision force measurement. This methodology successfully captures the relationship between the increasing collision speed and force, providing valuable insights into ice-induced forces and structural strain. It offers an effective measurement technique beneficial for designing ice-resistant structures. In conclusion, this paper enhances our understanding of ice–structure interactions, particularly in the domains of collision force and strain metrics.

Accurate crystal structures of ices from X-ray and ED with Hirshfeld atom refinement

Accurate crystal structures of ices from X-ray and ED with Hirshfeld atom refinement

In-situ ice strength distribution of anchor ice dams

Ice runs and ice jams can cause significant damage to infrastructure and other human interests. Accurate modelling and prediction of these events rely on data and assumptions about river ice properties. This paper seeks to address the lack of data on ice strength distributions and associated properties in small, steep rivers and to obtain a better understanding of those. To this end, an ice data collection campaign was carried out in the Sokna river in central Norway during the 2020–2021 winter field season. The following types of data were collected for anchor ice dams and level ice sections: Borehole Jack (BHJ) in-situ ice strength, ice thickness, ice density, thin section imagery and associated depth measurements. A total of 27 ice cores and 68 thin sections were successfully collected and processed. Furthermore, a survey was carried out recording GPS coordinates of anchor ice dams in the river. Meteorological and hydrological data was also collated, and large boulder location data was obtained through the analysis of aerial photography. Ice strength distributions and trends on how ice strength varies in small, steep rivers were obtained from these data. A binomial generalized linear model for predicting ice dam locations was developed using field measurements and aerial photography data. This model describes how river width, slope and to a lesser degree large boulder density affect ice dam location. Sinuosity was shown to have no effect on ice dam location. This work highlights the significant variation in microstructure and large-scale structure of ice in small, steep rivers.

Theoretical Prediction of the Anti-Icing Activity of Two-Dimensional Ice I.

Two-dimensional (2D) ice I is atomic-level ice that is composed of two interlocked atomic layers saturated with hydrogen bonds. It has recently been experimentally observed, but its properties have yet to be clarified. Accordingly, we theoretically studied the hydrophobic properties of 2D ice I. On the contrary, a simulation of a hydrogen fluoride molecule on a 2D ice surface manifested that it destroyed the 2D ice structure and connected new hydrogen bonds with water molecules. Investigations of the interfacial effect between 2D and three-dimensional (3D) ice films indicated that the network structure of 2D ice was not destroyed by a 3D ice surface, as the former was saturated with hydrogen bonds. However, the surface of 3D ice reorganized to form as many hydrogen bonds as possible. Thus, the 2D ice film was hydrophobic and inhibited the growth of 3D ice. This shows that if 2D ice can be produced on an industrial scale, it can be used as an anti-3D-icing agent under low temperatures.

From Past to Present The Most Mysterious Olympic Sport: A Review of Curling Sport

The popularity of curling, a target sport played on ice with rocks, has been steadily increasing. The number of World Curling Federation member countries has doubled in the last two decades. Shortly after taking part in the Olympics in 1998, curling became one of the most popular winter sports on TV. The reflections of the interest in the society have found a response in the world of science and an increase has been observed in the number of scientific studies on curling. However, despite the increase in studies, there is currently no comprehensive literature review that provides fundamental information about the sport of curling. The aim of this review is to provide general information about the sport of curling and its rules by filling the gap in the literature examining the scientific studies in this field. In this review the history, organization management, rules, strategy, ice properties, materials used and scientific research on the sport of curling are mentioned. While previous studies, particularly in the field of engineering, have explored aspects such as the structure of ice, sweeping techniques, and the movement of stones on ice, many mysteries still remain to be unrevealed.

Development of a Numerical Ice Tank Based on DEM and Physical Model Testing: Methods, Validations and Applications

The determination of ice loads on polar vessels and offshore structures is important for ice-resistant design, safe operation, and management of structural integrity in ice-infested waters. Physical model testing carried out in an ice tank/basin is usually an important technical approach for evaluating the ice loads. However, the high cost and time consumption make it difficult to perform multiple repetitions or numerous trials. Recently, the rapid development of high-performance computation techniques provides a usable alternative where the numerical methods represented by the discrete element method (DEM) have made remarkable contributions to the ice load predictions. Based on DEM simulations validated by physical model tests, numerical ice tanks can be developed as an effective complement to their counterparts. In this paper, a numerical ice tank based on 3D spherical DEM was established with respect to the small ice model basin of China Ship Scientific Research Center (CSSRC-SIMB). Based on spherical DEM with parallel bond model, the model tests of typical structures (vertical cylinder and inclined plate) in level ice sheets were established in the numerical ice tank, and the ice–structure interaction process under the same initial conditions was simulated. The accuracy of the simulations is verified by comparing the simulated ice loads with the measured ice loads from the model tests in the CSSRC-SIMB. Furthermore, the application of the numerical ice tank was extended to simulate the navigation of a Wass bow in level ice and broken ice conditions. The value of the break resistance of the Wass bow in level ice was evaluated, and the numerical ice tank produced results that were found to be consistent with those obtained from Lindqvist’s formula. The statistical properties of the bow load for different broken ice fields with the same initial physical conditions are analyzed by performing a repeatability test on the broken ice fields.

Mechanical behaviors and elastoplastic damage constitutive model for heterogeneous frozen soil

The significant feature that distinguishes frozen soil from unfrozen soil is the existence of ice structures within it. To investigate the effect of ice lenses on the mechanical properties of frozen soil. A series of tests were conducted on three types of heterogeneous frozen soil under different temperatures and normal stresses. The test results showed that the strength and ductility of frozen soil decrease as the number of ice lenses increase under the same temperature and normal stress. The ice lenses within frozen soil intensify its strength attenuation under loading, the damage variable considering the cutting effect of ice lenses were established based on the fracture mechanics, and an elastoplastic damage constitutive model for heterogeneous frozen soil was proposed. The method was redeveloped in COMSOL Multiphysics, and the rationality was verified based the test results. The variation of damage variable and plastic strains of heterogeneous frozen soil under shear loading were analyzed.​ Finally, a digital model of undisturbed frozen soil was established using X-ray CT, and the failure mechanisms of the undisturbed frozen soil were investigated by the proposed model.

Accurate crystal structures of ices from X-ray and ED with Hirshfeld atom refinement

Accurate crystal structures of ices from X-ray and ED with Hirshfeld atom refinement

Physical properties of methanol (CH3OH) ice as a function of temperature: density, infrared band strengths, and crystallization

ABSTRACT The presence of methanol among the common ice components in interstellar clouds and protostellar envelopes has been confirmed by the James Webb Space Telescope (McClure et al. 2023). Methanol is often detected in the gas phase towards lines of sight shielded from UV radiation. We measured the volumetric density of methanol ice grown under simulated interstellar conditions and the infrared spectroscopy at different deposition temperatures and during the warm-up. The IR band strengths are provided, and the experimental spectra are compared to those computed with a model. The transition from amorphous to crystalline methanol ice was also explored. Finally, we propose new observations of methanol ice at high resolution to probe the methanol ice structure.

Observing ice structure of micron-sized vapor-deposited ice with an x-ray free-electron laser.

The direct observation of the structure of micrometer-sized vapor-deposited ice is performed at Pohang Accelerator Laboratory x-ray free electron laser (PAL-XFEL). The formation of micrometer-sized ice crystals and their structure is important in various fields, including atmospheric science, cryobiology, and astrophysics, but understanding the structure of micrometer-sized ice crystals remains challenging due to the lack of direct observation. Using intense x-ray diffraction from PAL-XFEL, we could observe the structure of micrometer-sized vapor-deposited ice below 150 K with a thickness of 2-50 μm grown in an ultrahigh vacuum chamber. The structure of the ice grown comprises cubic and hexagonal sequences that are randomly arranged to produce a stacking-disordered ice. We observed that ice with a high cubicity of more than 80% was transformed to partially oriented hexagonal ice when the thickness of the ice deposition grew beyond 5 μm. This suggests that precise temperature control and clean deposition conditions allow μm-thick ice films with high cubicity to be grown on hydrophilic Si3N4 membranes. The low influence of impurities could enable in situ diffraction experiments of ice nucleation and growth from interfacial layers to bulk ice.