Ice Pieces Research Articles

The use of X-Ray computed tomography for the diagnosis of composite structures in the energy sector

RELEVANCE In modern Russia, an important condition for the development of the Far North and Far Eastern regions is to provide these regions with electricity. In remote areas with increased wind potential, the use of wind power plants, the main structural elements of which are made of polymer composite materials (PCM), is promising. The most dangerous operational defect of the PCM is shock damage: due to hail strikes or pieces of ice that broke off during heating of the blades, as well as lightning strikes. Such defects, which are difficult to detect during visual inspection, can significantly reduce the strength and service life of the structure. At the stages of technology development and design certification, the use of modern methods of non-destructive testing is required.PURPOSE. To evaluate the possibilities of X-ray computed tomography for the diagnosis of structural elements made of PCM with impact damage.METHODS. After applying a low-speed impact to fragments of the blades of the wind turbine, a visual inspection and measurement of the size of internal injuries are carried out on a Phoenix V |Tome|X X-ray computed tomograph.RESULTS The nature of the damage inflicted with different impact energies on the most critical areas of fragments of the airfoil blades and the stringer panel is investigated. The depth and area of damage have been determined. The nature and size of internal injuries were studied using an X-rayCOMPUTED tomograph. conclusion. The results obtained allow us to estimate with high accuracy the size and location of impact damage, which can be used in strength calculations.

Acoustic observations of individual bubble release events from melting glacier ice in an arctic fjord

Melting below the waterline of marine-terminating glaciers and ice sheets has the potential to remove ice that is holding back land-based ice upstream, and increase the rate of global mean sea level rise. It is difficult to observe this melting directly, and the physical processes involved remain an active area of study. As glacier ice melts, the air bubbles trapped in the ice are released into the water. The air bubbles are often at greater pressure than the surrounding hydrostatic pressure in the water, causing them to be released explosively and generate sound through resulting monopole oscillations. Studying this sound at the level of individual bubbles provides an opportunity to learn more about the role of the bubbles in affecting heat flux across the ice-water boundary layer. It is also essential for proposed efforts to use acoustic emissions as a tool to quantify glacier-scale submarine melting. We will present and discuss observations made at the ice-water interface of floating pieces of glacier ice in an Arctic fjord. These observations included measurements of the water thermal structure, velocity, and salinity, as well as ablation of the ice face, made concurrently with acoustic measurements of bubble release pulses from a 2-element hydrophone array.

Brief communication: A technique for making in situ measurements at the ice–water boundary of small pieces of floating glacier ice

Abstract. This paper presents an apparatus and associated methods for making direct in situ measurements of the ice–water boundary of small pieces of floating glacier ice. The method involves approaching ice pieces in a small boat and attaching a frame with instruments on it to them using ice screws. These types of measurements provide an opportunity to study small-scale processes at the ice–water interface which control heat flux across the boundary. Recent studies have suggested that current parameterizations of these processes may be performing poorly. Improving understanding of these processes may allow for more accurate theoretical and model descriptions of submarine melting.

Image analysis methods for the flow of ice pieces on a hull surface in ice tank tests

Image analysis methods for the flow of ice pieces on a hull surface in ice tank tests

Quantifying the ice test in halitosis patients

AbstractObjectivesOdor is in the oral air when halitosis occurs orally. Because oral gases shrink when cooled, oral halitosis disappears when a piece of ice is placed in the patient's mouth. This physical phenomenon provides a basis for distinguishing oral from non‐oral halitosis but has yet to be quantified.Material and methodsThe records of 29 halitosis patients were retrospectively analyzed. Gas concentrations were measured with a portable gas detector (IBRID‐MX6) before and after cooling the mouth with 1 × 1 × 2 cm ice for 30 s. Patients were asked to rate their halitosis. Tongue temperature and oral gas concentrations were compared with paired t‐tests and one‐way ANOVA.ResultsThe tongue cooled by an average of 13.09°C with ice (from 36.0 to 22.4°C). The mean values of the concentrations of VOC, NH3, H2S, and H2 decreased proportionally with cooling: 74.10%, 77.51%, 81.26%, and 96.12%, respectively. The self‐reported halitosis score decreased from 4 to 0 (n = 29, p < 0001).ConclusionsIt can be concluded that the ice test suppresses oral gases in sufficient quantity to detect oral halitosis.

Brash ice macroporosity and piece size distribution in ship channels

Merchant vessels' performance on brash ice plays an important role in navigation in fast ice conditions in Northern Baltic ports. Among many parameters, the piece size distribution and macroporosity of the brash ice influence the accuracy of the model simulations of ship performance in brash ice. These properties also govern the brash ice accumulation and consolidation in ship channels. The current work presents analyses of macroporosity and piece size distribution from three full-scale brash ice channels investigated during winters 2020–21 and 2021–22. The results provide insights into brash ice macroporosity and piece size distribution. Smaller brash ice pieces exhibited higher porosity. On each measured cross-section, the average macroporosity ranged from 1.4% to 23%, with standard deviations of 3.8% and 16%, respectively. Porosity variations were observed in relation to equivalent brash ice thickness, the number of ship passages, and cumulative freezing air temperatures. Total porosity and the channel's brash ice porosity initially increased with breaking events and then stabilized at approximately 23% and 30%, respectively, after 9 passages. In contrast, side ridge porosity increased initially (up to 23%) and subsequently decreased. The initial total, brash ice and side ridge maximal porosities after the breaking event were estimated equal to 25%, 35% and 30%, respectively. The first two channels, which were navigated a total of 9 and 10 times, had an average degree of brash ice consolidation equal to 0.84 and 0.76, and an average degree of side ridge consolidation equal to 1.1 and 1.0, respectively. The third channel, characterized by frequent navigation, exhibited a consolidation degree of 0.82 for brash ice and 1.35 in the side ridges. The average vertical piece size across all cross-sections ranged from 0.28 m to 0.52 m with standard deviations of 0.16 m and 0.25 m. The average horizontal piece size ranged from 0.33 m to 0.4 m with standard deviations between 0.2 m and 0.34 m. The horizontal piece size distribution of brash ice was best described by the probability density function of a three-parameter lognormal distribution.

Arctic naval launch and recovery operations, under ice impact interactions

This study analyses dynamic influence of stochastic vibro-impact ship behaviour on the ship's launch and recovery capability. To deliver cargo and people to the Arctic regions, ships must withstand harsh environmental conditions and interact with large floating ice pieces. This interaction may result in impact-type loading of a ship hull by ice, preventing planned navigation and even causing to abort of some routine launch and recovery operations of delivering cargo or other equipment. The major safety concern is the risk of collision between the payload and the mother ship hull. The ship-based crane, which served for conducting launch and recovery operations, was assumed to be rigid, mimicking the ship dynamics, whereas the payload is modelled as a single-degree-of-freedom pendulum. This study advocates practical engineering approach, applicable to various scenarios with vessels operating in relevant in situ environmental sea and ice conditions. The proposed study intends to contribute to improving launch and recovery operational reliability, as well as motion control, especially in Arctic aquatic regions. When mentioning Arctic and defence technologies, launch and recovery systems have significant relevance for unmanned vehicles onboard ships.

Wind Drift, Breakdown, and Pile Up of the Ice Field

This article contains the analytical model of the drift of a separate ice field under the action of wind and current, in which velocities and directions can vary over time. The model takes into account the mass of ice, added mass of seawater, and the effects of the wind and current on the ice field in forming the friction on its upper and underwater surfaces and the frontal resistance on its end (forward and backward) surfaces. Simulation of the wind drift of the ice field showed the drift velocity exceeds the considerable known velocity of a compact ice cover drift. A drifting ice field has a certain kinetic energy that should be released when a collision occurs with an unmovable obstacle, and spent on brittle breakdown of a quantity of the ice field. The volume of formed small ice pieces (fragments of ice field) was estimated by comparison of the specific energy of the sea ice brittle destruction and the kinetic energy of the drifting ice field. The article presents the results of the estimation of the possible volume of the ice pieces and the scales of formed piles as a result of a collision with an obstacle, depending on the initial dimensions of the ice field and wind speed. Developed models and the results of computer modeling can be used to estimate the ice pile sizes near the stationary platforms and terminals on the Arctic seas.

A two-way coupling method for simulating wave-induced breakup of ice floes based on SPH

In this paper, a new numerical method for simulating the breakup of ice floes in water waves will be presented. The method is based on Smoothed Particle Hydrodynamics (SPH) but several new numerical techniques are developed to address the challenges associated with wave-ice interaction including breakup. One of them is the new interaction model for fluid-ice interaction, which is not only suitable for small density ratio but also for large density ratio. This model may also be employed by other methods for dealing with general fluid-structure integration. In addition, a technique for modelling the separation of broken ice pieces is developed. Apart from these, a treatment is proposed to rectify the problem caused by unequal time steps in simulating ice and fluid, which is necessary for achieving higher computational efficiency. The numerical method is validated by comparing the numerical results with the experimental data available in literature, which shows that the agreement between them is satisfactory. On this basis, the breakup of ice floes induced by solitary waves and focused waves are studied. To the best of knowledge of the authors, it is the first method which can simulate the ice breaking in waves by two-way coupling approach. The results for ice breaking in solitary and focused waves have not been found so far in previous publications available in literature.

Выбор движителя для подводного аппарата судовой энергетической установки

The article considers the problem of improving and providing the ability to regulate motion of the parts of a ship power plant (underwater apparatus) used to eliminate the emergency spills of oil and petroleum products. The problem of emergency spills of oil and their elimination is urgent today. At all stages of oil use, from oil exploration and production to waste disposal, the environment is polluted due to oil spills, emissions of harmful substances into the atmosphere, water and onshore. As the oil product manufacturing develops, the volumes of accidental spills also increase. Emergency spills of oil and oil products lead to irreversible consequences and large resources are allocated for their elimination. Using the underwater apparatus of the ship power plant for elimination of emergency spills of oil and oil products allows sorbent spraying in broken and solid ice. There has been developed a pilot model with a ballasting device under water at a constant depth, which creates difficulties when maneuvering and moving it under thick ice, as well as in broken ice pieces of a large size. Calculations help choose the most optimal engines and propellers to regulate the depth of the apparatus’s lifting and submersing during its operation. It has been recommended to introduce a new technical device for liquidation of emergency spills of oil and oil products, which has no analogues in the world.

Numerical analysis of hydrodynamic forces on an ice piece downstream of floating ice pieces

Numerical analysis of hydrodynamic forces on an ice piece downstream of floating ice pieces

Horizon detection and tracking in sea-ice conditions using machine vision

An automated process is proposed for horizon detection and tracking using machine vision cameras and in polar, sea-ice conditions. These conditions present unique challenges for machine vision applications, such as a large amount of clutter (e.g. icebergs) and secondary edge lines from broken ice pieces. The process is divided in two parts: a more computationally expensive, yet robust detection algorithm in the first stage, based on Convolutional Neural Networks, and used to detect the horizon line in an arbitrary sea-ice image; followed by a tracking algorithm, responsible of efficiently detecting the horizon line in the subsequent images of a sequence. We propose two tracking algorithms, one based on the traditional Canny and Hough line detection methods; and a second novel approach using entropy as a measure of randomness, to segment between sea-ice and sky. Our automated process was compared to manually obtained ground-truth data and the results indicate good agreement, especially for the texture-based tracking algorithm.

Torsional vibrations of Polar-Class shaftlines: Correlating ice–propeller interaction torque to sea ice thickness

During ship operations in ice-covered waters, propellers often collide with sea ice pieces. This phenomenon represents a severe hazard that affects the torsional stress state of shafting systems and, ultimately, the ship propulsion system reliability. Classification Societies provide ship designers with design loads and criteria to simulate these events, but there are still uncertainties on the actual characteristics of the impacts that ice-class propellers undergo. This paper presents the results of a research activity that combines experimental measurements and numerical analysis to identify the correlation between ice-induced propeller loads and sea ice conditions. The Canadian Coast Guard (CCG) icebreaker Henry Larsen is considered a case study; we simulate its propulsion shaftline as a lumped-element system and validate this model against full-scale data. A series of numerical simulations to predict the ice-induced impact loads on the propeller was performed by using measured dynamic torque data as the analysis input. Finally, the resulting values were correlated with the ice thickness data acquired while the ship was operating. We compare this ice–propeller torque distribution with the homologous quantities calculated as per the current Polar Class framework. The results show high torque response values even when the ship operates in thin ice.

Prebiotic Formation of Catalytically Active Dipeptides via Trimetaphosphate Activation.

Short peptides with unique catalytic abilities are regarded as the simplest enzymes possessing great potential as primordial species to take part in the chemical origin of life. However, prebiotic acquisition pathways of catalytically active peptides remain unclear. In this study, a microwave reactor was used to simulate hydrothermal environments, such as hydrothermal vents, either submarine or subaerial environments. A refrigerator freezer was used to make ice pieces that mimic extra-terrestrial ice crystals. Serine (Ser) and histidine (His) were used as examples, and the formation of small functional peptides involving sodium trimetaphosphate (P3 m) activation in an alkaline aqueous solution was investigated under the two typical prebiotic environments mentioned above. The obtained experimental results showed that the targeted small functional peptide Ser-His and its sequence isomer His-Ser could be formed in all simulated environments, even in the presence of disruptive amino acids, such as alanine (Ala), proline (Pro), and aspartic acid (Asp), in the reaction systems. Notably, Pro may have some effect on the chirality of the produced dipeptides by screening the configuration of the amino acids. Owing to the lack of disturbance of N-O migration in the CAPA (His) intermediate, the CAPA intermediate of His is more stable than that of Ser; therefore, His is more easily activated by P3 m to form a dipeptide with His at the N-terminal. The yield of His-Ser is at least about four times that of Ser-His in the two simulated prebiotic environments. Additionally, our work suggests that more types of amino acids can be activated simultaneously by P3 m to produce various dipeptides, which will provide abundant raw materials for the evolution of life molecules.

The optimization method of wing ice shape regulation based on flight dynamics characteristics

Ice on aircraft wing changes the aircraft aerodynamic shape, and has negative effects on flight dynamic characteristics, seriously threatening flight safety. Plasma ice shape regulation is a new de-icing method. Plasma actuator produces an apparent thermal effect, which is designed to dissolve the continuous ice into intermittent ice pieces. How to achieve the optimal regulation ice shape to improve the flight dynamics characteristics under icing conditions is a technical problem restricting the application of this method. A simulation ice shape based on previous ice tunnel experiments and a scale model of swept wing were established. The aerodynamic parameters of no ice, full ice, and two regulation ice schemes were obtained based on wind tunnel. Six degrees of freedom flight dynamics model was established, and flight simulation had been carried out. As the analysis of trim characteristics, dynamic stability, and maneuverability, flight dynamics characteristics were better improved when the ratio of ice width to the mean aerodynamic chord was 0.15. The evaluation method of plasma ice shape regulation schemes was proposed. The proposed method, which can compare and optimize the arrangement of plasma actuators, realized the optimal regulation ice shape on the premise of balancing flight safety and energy consumption.

An investigation on the speed dependence of ice resistance using an advanced CFD+DEM approach based on pre-sawn ice tests

Over the past decades, the underlying mechanism of level ice resistance changing with ship speed has not been fully understood, particularly the resistance component due to ship interactions with broken ice pieces. Pre-sawn ice test can negate icebreaking component from the whole resistance of a ship in level ice, providing an effective approach to decompose ship-ice interactions and investigate the speed-dependent resistance from broken ice pieces. This work has built a computational model that can realistically simulate a ship advancing in a pre-sawn ice channel. The model applies Computational Fluid Dynamics (CFD) to solve the flow around an advancing ship, which is coupled with an enhanced Discrete Element Method (DEM) to model pre-sawn ice pieces. Model-scale experiments have also been conducted at the Aalto Ice Tank to validate the simulations, which shows the computational model can provide a reasonable estimation of the pre-sawn ice's resistance and movement around the ship. Upon validation, the dependence of ice resistance on ship speed was analysed. The simulations enable underwater monitoring of the ice motions, indicating that the speed dependence results from the mass of ice submerged underneath the ship and the displacement of broken ice induced by the ship. The identified relationships are more complex than the widely-used assumption that ice resistance linearly changes with ship speed in all cases, which provides a deeper understanding of ice resistance. As such, the findings from this study can potentially facilitate improvements in relevant empirical equations, useful for ship design, operational strategies and maritime management in polar regions.

Испытательный стенд, результаты проведения испытаний датчика обледенения

The article presents a test bench for studying the characteristics of the sensor for detecting ice or snow on any controlled surface. To conduct a laboratory experiment, a test bench has been developed, consisting of three parts: executive one, which includes a test object and systems, that ensure the impact of various operational factors; informational-control one, which includes control systems and measuring systems that inform on a test object and bench behavior parameters; power supply systems. ATmega2560 microcontroller on ARDUINO Mega 2560 hardware platform with SD card and real-time clock was used as an icing sensor controller. Block diagram of the test bench is given. Testing program and methodology are presented. Based on the test results, dependences of platen working surface temperature from the time passed after heater cut-in were plotted. For to save time, pre-prepared pieces of ice were placed on surface of the platens in order to simulate their icing. To evaluate icing sensor functioning in real weather conditions and to assess method for icing detection on a working surface, a computer simulation model was developed and studied in MATLAB environment. It allows to hold analysis of ongoing thermal processes in the system “object of heating”. The results of the fulfilled tests are discussed.

Ice accretion, shedding, and melting on cable-stayed bridges: A laboratory performance assessment

Ice accretion on cable-stayed bridge surfaces increases loading, affects the structures' aerodynamic behavior, and heightens the risk of ice pieces detaching and falling onto bridge traffic. Here we propose a comprehensive laboratory-based procedure for evaluating materials to reduce ice accretion and prevent ice shedding on cable-stayed bridge. We then assess our laboratory-based procedure by testing four high-density polyethylene sheath configurations for cable-stayed bridges. These sheaths differ in their surface finishes, chemistry, and surface roughness. We present a three-step controlled-environment procedure involving (i) the physical characterization of the surface; (ii) an evaluation of surface behavior under laboratory icing tests; and (iii) an assessment of ice accretion at −10 °C under freezing rain conditions, followed by shedding and melting phases. This testing procedure provides a simple means of evaluating geometric changes and surface modifications, including icephobicity, under repeatable and comparable conditions. Our approach could serve in the design and optimization of materials prior to their deployment under actual operational conditions.

Medium-scale laboratory investigation of the effect of confinement on ice rubble strength and failure behavior

Understanding the deformation and strength of ice rubble is key to estimating ice ridge loads on ships, offshore structures and subsea infrastructure. Medium-scale punch tests were conducted at C-CORE's Cold Room facility to measure and observe the strength and failure behavior of freshwater ice rubble. A custom-built punch box measuring 3.05 m in length and 0.94 m in width and height was used to perform the tests. The box walls were made from Plexiglas so that failure mechanisms could be observed. Ice rubble beams of nominal thickness 50 cm were produced by placing randomly sized ice pieces into the punch box, filled with water at its freezing temperature. Beams were left for a period of 4 h to consolidate under vertical confining pressures ranging from 0 kPa to 40 kPa. The ice rubble beam was deformed by pushing a platen vertically downwards though the center of the beam until failure. Results showed that the failure behavior of the ice rubble beam was controlled by the degree of freeze-bonding/sintering between the blocks, which significantly increases with applied confinement.

Application of Radar Image Fusion Method to Near-Field Sea Ice Warning for Autonomous Ships in the Polar Region

Mastering the real-time dynamics of near-field sea ice is the primary condition to guaranteeing the navigation safety of autonomous ships in the polar region. In this study, a radar image fusion process combining marine radar and ice radar is proposed, which can effectively solve the problems of redundant information and spatial registration during image fusion. Then, using the fused radar images, this study proposes a set of near-field sea ice risk assessment and warning processes applicable to both low- and high-sea-ice-concentration situations. The sea ice risk indexes in these two situations are constructed by using four variables: sea ice area, sea ice grayscale, distance between sea ice and the own-ship, and relative bearing of sea ice and the own-ship. Finally, visualization processing is carried out according to the size of the risk index values of each piece of sea ice to achieve a better near-field sea ice risk assessment and warning effect. According to the example demonstration results, through the radar image fusion process and the set of near-field sea ice risk assessment and warning processes proposed in this study, the sea ice risk distribution in the near-field area of the ship can be well obtained, which provides effective support for the assisted decision-making of autonomous navigation in the polar region.