Natural Ice Research Articles

Toward Better Constrained Scattering Models for Natural Ice Crystals in the Visible Region

AbstractIn this work, we introduce a method for constraining the optical scattering models of natural ice crystals based on in‐situ measurements. Specifically the measured angular scattering functions for ice crystals can be used to compute a set of the asymmetry parameter (g) and the corresponding complexity parameter (Cp). It is demonstrated that the g‐Cp relation can give valuable information on the morphology of ice crystal. The validity of the methods is shown from theoretical perspectives and the geometric‐optics ray‐tracing simulations. As an application, we investigate rimed ice crystals from in‐situ measurements and found that (a) the Cp parameter is very well correlated with the surface riming degree and (b) only those models with both roughness and internal scattering can explain the observed g‐Cp relation for rimed particles.

The Effect of Pseudofrazil Particle Entrainment on Salinity Measurements

AbstractSalinity effects of particles entrained into conductivity cells have previously mainly been studied in the context of suspended sediment. Particles influencing conductivity cells can also be small ice crystals (frazil) that may form in supercooled water. The detection of supercooled water depends on accurate, high precision temperature, salinity and pressure measurements. As it is currently not possible to measure salinity in situ, the standard procedure is to measure conductance over a known volume and calculate salinity. Frazil ice entrained into a conductivity cell changes the volume of conductive fluid in the conductivity cell, thus changing the conductivity, salinity and supercooling measurements. We present results on the effect of entraining microplastic into a Sea‐Bird Electronics conductivity cell to simulate the effect of frazil. We show that particle volumes comparable to frazil volumes observed in the ocean change the measured conductivity and led to changes in calculated supercooling between 0.3 and 10 mK, possibly up to the same order of magnitude as naturally observed supercooling in the ocean. Further, we demonstrate that where supercooling is present, natural frazil ice concentrations can have an appreciable effect on parameters calculated with both the Equation of State of Seawater 1980 and Thermodynamic Equation of Seawater 2010 equations of state of seawater. Thus, to ensure accurate measurements in locations of very high frazil concentration, the entrainment of frazil needs to be prevented, which is not possible with methods currently available, or corrected for. An example for such a correction is given and could be modified to be applicable to other particles, for example, sediment.

Упрочнение поликристаллического льда наночастицами диоксида кремния

Ice as a construction material has a number of advantages in Arctics. It is local renewable ecologically safe resource, and it does not require supplying from mainland. However, mechanical characteristics of natural ice is rather low. Potential of known techniques of ice strengthening employing reinforcement by microfibers or macroscopic components is limited. The paper describes strengthening of ice matrix using nanodisperce silica particles. Sixfold reduction of grain size induced by adding 10% wt of SiO2 nanoparticles results in 2.5 times increase in strength limit in uniaxial compression test and more than an order of magnitude increase in fracture energy.

Simulation calculation of 3D electric field and natural flashover analysis of ice‐covered silicone rubber insulator

AbstractThe effects of uneven icing, number of icicles, inclination angle of icicle, ice pallets and arc ignition on the electric field are ignored for the two‐dimensional axisymmetric model of ice‐covered insulator. Therefore, a 3D simulation model was developed in this paper. The average electric field strength of air gap (Eav) and maximum field strength of icicle tip (Emax) were determined to characterize the influence of various factors on the electric field distortion degree. The results show that compared with the insulator without ice and with a dry ice, the supply voltage is almost entirely applied to all icicle air gaps for a wet ice‐covered insulator. Eav is independent of icicle diameter and icicle number but increases with the increment of icicle length and icicle inclination angle. Emax raises with the increase of icicle length, icicle number, icicle inclination angle and icicle diameter. As the source of electric field distortion, the ice pallets on the surface of the sheds rise the field strength of air gap. Based on the simulation analysis and natural icing test, the applied voltage is redistributed in the remaining air gaps when an arc occurs in the gap near the high‐voltage terminal, thereby causing the subsequent flashover.

Universality in azimuthal asymmetry of anisotropic sea-ice reflectance.

We study the azimuthal asymmetry of the spectral bidirectional reflectance distribution function (BRDF) of an optically thick sea-ice layer. From radiative transfer modeling, we find that the azimuth-dependent part of the BRDF ceases to change rather rapidly with an increase in the optical thickness of the layer and tends to a nearly universal angular dependence, insensitive to the specific law of single scattering in the ice. The effect of the scattering phase function manifests itself only in the value of a pre-factor in the azimuth-dependent part of the BRDF. The universality stems from the refractive index mismatch at the air/ice interface and should occur for any natural ice containing large (compared to the wavelength) inclusions. The specified part of the BRDF is governed by sub-diffusive radiation transport and, at large illumination zenith angles, can make a noticeable contribution to the spectral albedo of the layer in the visible range.

Experimental Investigation of Uniaxial Compressive Strength of Distilled Water Ice at Different Growth Temperatures

The existence of ice in nature will threaten the safety of navigation and water operations in cold regions. In order to improve the knowledge system of ice strength, the uniaxial compressive strength of distilled water ice grown at different temperatures is studied in this paper. Distilled water ice samples grown at −5 °C, −10 °C, −15 °C, −20 °C, −25 °C, −30 °C and −35 °C are prepared in the cryogenic laboratory. The density and grain size are measured. The uniaxial compressive strength tests are carried out at −10 °C. The stress-strain curves and the mechanical properties and failure modes of ice are obtained by loading along the vertical direction in the strain rate range of 10−6 s−1 to 10−2 s−1. It is found that the uniaxial compressive strength of ice is a power function of strain rate and a linear relationship with the −1/2 power of grain size. Combined with the relationship between strength and grain size and the relationship between grain size and temperature, it is deduced that the peak compressive strength has a logarithmic relationship with the growth temperature. In addition, it shows that the growth temperature affects the strength of ice by controlling the grain size.

Experimental Study on the Noise Evolution of a Horizontal Axis Icing Wind Turbine Based on a Small Microphone Array

In recent years, the global energy mix is shifting towards sustainable energy systems due to the energy crisis and the prominence of ecological climate change. Wind energy resources are abundant in cold regions, and wind turbines are increasingly operating in cold regions with wet natural environments, increasing the risk of wind turbine blade icing. To address the problem of noise source distribution and the frequency characteristic variation of wind turbines in natural icing environments, this paper uses a 112-channel microphone array to acquire the acoustic signals of a horizontal axis wind turbine with a diameter of 2.45m. Using the beamforming technique, the wind turbine noise evolution law characteristics under natural icing environment were studied by field experiments, and the noise source distribution and noise increase in different frequency bands under different icing mass and positions and different angles of attack were analyzed in detail. The results show that under the leading-edge and windward-side icing, the noise source gradually moves toward the blade tip along the spanwise direction with the increase in ice mass. In addition, the total sound pressure level at 460 r/min, 520 r/min, 580 r/min, and 640 r/min are increased by 0.82 dB, 0.85 dB, 0.91 dB, and 0.95 dB, respectively for the leading-edge icing condition in comparison with the uniform icing over the windward side of the blade.

Dielectric constant of ice in natural rivers

Ground-penetrating radar (GPR) is a non-contact measurement method widely used to determine ice thickness, which is an important hydrological parameter of rivers in winter. The accuracy of GPR measurements of ice thicknesses is highly dependent on the dielectric constant value of ice. Research on the dielectric constant of ice has mainly focused on pure ice; however, pure ice is not commonly found in natural rivers. In fact, hydrodynamic and meteorological factors, as well as boundary conditions, affect ice in natural rivers, which can be treated as a mixture of pure ice, air bubbles, sediment, and pure water. Therefore, the dielectric constant of ice in natural rivers often differs from the theoretical value of pure ice, a fact that has often been neglected in prototype measurements. During eight years of prototype monitoring in the Heilong River and Yellow River (China), it was found that variations in the dielectric constants of ice in the two rivers produced errors in the GPR ice thickness measurements. In this study, we measure the dielectric constant of ice at 158 measurement points across more than 20 river sections, and we present a recommended range of values for the dielectric constant. Regarding media, such as air bubbles, sediment, and water in natural river ice, we analyze sand (both dry and wet) in ice-bound sediment and the effects of air bubbles, sediment, and water upon the ice's dielectric constant. Using temperature and voltage measuring rods installed in the ice, we demonstrate that the water content in the ice differs significantly according to the freeze-up and breakup periods. The present study recommends guidelines including suitable timing, ice-condition, and dielectric-constant reference values for GPR-based ice thickness measurements to improve the measurement accuracy. Thus, this work can serve as a reference for future applications in similar rivers.

Phase Transition between Crystalline Variants of Ordinary Ice.

Water is one of the most abundant molecules on Earth. However, this common and "simple" material has more than 18 different phases, which poses a great challenge to theoretically study the nature of water and ice. We designed two reaction coordinates that can distinguish between water and various ice states and used them to efficiently sample all possible states of the system in all-atom molecular dynamics simulation at ambient temperature and pressure. Various structural and thermodynamics properties, including the water-ice phase diagrams, can thus be calculated. We also present a simple model that successfully explains the thermodynamic stability of different ice states. Our work provides effective methods and data for theoretical studies of different phases of water and ice.

Physical Modeling of Ice Cover Deformation Under the Action of a Moving Load at Low Speed

The current paper considers the possibility of physical modeling of ice cover deformation under the action of a moving load at low speed. Using an equation for elastic plate oscillations on the foundation of a hydraulic type, it is shown that similarity of a stress and strain state (SSS) of model ice can be achieved but within the scope of the approaches based on a classical theory of Nogid-Shimansky modeling of ice cover. Taking into account certain complications connected with practical implementation of the above method, the applicability of a reduced-thickness ice model developed at NNSTU is investigated. This model uses the ice thickness that intentionally does not comply with the similarity requirements, all other requirements being satisfied, thus providing incomplete similarity of the model. Some disagreements with a Nogid-Shimansky model connected with that are revealed and their influence on the end result is evaluated. The applicability of a thin ice model is investigated in natural cooled model tanks of classical shape used for modeling of load movement at low speed. The results of the experimental investigation of ice cover deformation under the action of a moving load using a model for the natural thin ice are given. The modification of a wave shape and maximum ice deflection depending on change of a movement speed and loading are investigated. The connection of decrease of a ratio of the deflection basin profile area to the outward ice bending profile in front of a moving load with increase of speed at the start of the movement is demonstrated, which can be an evidence of a sharp growth of energy expenses for ice cover deformation when the interaction between the technical facility and ice cannot be considered as quasistatic. An exact evaluation of such expenditures is crucial when designing the ice-breaking facilities clearing a path through floe ice.

Sea Ice–Water Classification of RADARSAT-2 Imagery Based on Residual Neural Networks (ResNet) with Regional Pooling

Sea ice mapping plays an integral role in ship navigation and meteorological modeling in the polar regions. Numerous published studies in sea ice classification using synthetic aperture radar (SAR) have reported high classification rates. However, many of these focus on numerical results based on sample points and ignore the quality of the inferred sea ice maps. We have designed and implemented a novel SAR sea ice classification algorithm where the spatial context, obtained by the unsupervised IRGS segmentation algorithm, is integrated with texture features extracted by a residual neural network (ResNet) and, using regional pooling, classifies ice and water. This algorithm is trained and tested on a published dataset and cross-validated using leave-one-out (LOO) strategy, obtaining an overall accuracy of 99.67% and outperforming several existing algorithms. In addition, visual results show that this new method produces sea ice maps with natural ice–water boundaries and fewer ice and water errors.

Icing on Full-Scale Swept Wings in Flight and Icing Wind Tunnel

Inflight ice accretion on aircraft wings has been critically important for development and certification of transport category aircraft. With recent efforts toward certification by analysis, it is becoming increasingly important to characterize ice accretions in icing wind tunnels, the primary source of validation data for higher-fidelity three-dimensional ice shape analysis codes to be used in aircraft certification, in comparison with those in natural icing environments. In this study, a series of natural icing flight tests and icing wind tunnel tests were conducted on a transport category aircraft. The results were compared at similar test conditions on protected and unprotected surfaces of swept wings and empennage. For unprotected surfaces, both tests resulted in scallop ice, with natural icing flight test resulting in significantly smaller ice accretions. For protected surfaces, runback ice was formed on the lower wing surface in both tests, with natural icing flight test resulting in significantly less and sparser runback ice. Differences in scallop ice structures, limitations of icing wind tunnels, and scaling methods are considered the potential contributing factors to the differences. The results indicate a need for further studies on case-to-case comparison of ice accretions in the two test methods focusing on full-scale aircraft conditions.

Laboratory Studies on the Parametrization Scheme of the Melting Rate of Ice–Air and Ice–Water Interfaces

During the melt season, surface melting, bottom melting, and lateral melting co-occur in natural ice floes. The bottom melting rate is larger than the lateral melting rate, followed by the surface melting rate, and the smaller the size of an ice floe, the higher the lateral melting rate. To add the scale index of small-scale ice to the melting parametrization scheme, experiments on the melting process of sea ice and artificial fresh-water ice samples in the shape of a disc were carried out in a low-temperature laboratory, under conditions of no radiation, current, or wind, with controlled air and water temperatures. The variations of diameter, thickness, and mass of the ice discs were measured through the experiments. According to the experimental data, a new indicator was created using the ratio of the diameter to the thickness of an ice sample. Based on physical and statistical analyses, the relationships between the surface/bottom melting rates and temperature gradient were formulated. Additionally, the relationships among the lateral melting rate, temperature difference, and the ratio of the diameter to the thickness were also quantified. The equations can be applied to the melting parametrization scheme of ice for a range of diameters up to 100 m, which covers simulations of the energy and mass balance values of the Arctic sea ice and coastal freshwater ice during the summer melt season.

Optimization of Environmental Parameters of Ice and Snow Sports Venues Based on the BP Neural Network and Wireless Communication Technology

Ice and snow sports have become a scene of attraction nowadays. It not only encourages sports but also earns more revenue through tourism. Tourists love and admire this kind of sport because of its uniqueness, unlike other sports. The Olympic Games also conduct ice and snow sports under the Winter Olympic Sports. This kind of sport is played in ice rinks. Ice rinks are of two types, namely, natural and artificial. Natural ice rinks are formed in snowy regions, whereas artificial ice rinks can be set up anywhere with the help of technology. An artificial or natural ice rink, a sports venue, or a stadium is constructed accordingly. This research focuses on the optimization of environmental parameters of the ice and snow sports venue based on the BP neural network and wireless communication technology. There are various factors to be monitored when an indoor ice and snow sports venue is being considered. They are temperature monitoring, health monitoring of the audience, natural disaster detection and alarm in the case of natural ice rinks, and building safety concerning the climatic conditions. The proposed methodology uses BP neural networks and wireless communication technology to optimize the environmental parameters of the ice and snow sports venue. It has been demonstrated to have numerous advantages over traditional ice and snow sports methods. In this research, the convolutional BP neural network algorithm was implemented to analyse the environmental parameters of the chosen sport. The proposed algorithm is compared with the existing weighted centroid model. The results show that the proposed model has achieved an accuracy of 99.45%.

Observations of Stress‐Strain in Drifting Sea Ice at Floe Scale

AbstractThe mechanical deformation of sea ice has substantial influence over large‐scale (e.g., >10 km) ice properties, such as the ice thickness distribution, as well as small‐scale (e.g., <50 m) features, including leads and ridges. The conditions leading to sea ice fracture are frequently studied in the context of a uniform ice sheet. Natural sea ice, however, is highly heterogeneous and riddled with flaws. Failure occurs primarily as brittle fracture localized in space and time where stresses, and strain rates, locally exceed failure criteria. Here we seek to better understand the mechanical deformation and fracture of sea ice under such typical field conditions. In particular, we aim to characterize how forces propagate across an approximately 1 km2 heterogeneous domain by observing the stress‐strain field in an ice floe at resolutions required to capture pre‐fracture elastic strains. The combination of instruments deployed allow a detailed view of the formation, propagation, parting, and subsequent shearing of a fracture in natural sea ice, providing field evidence of modes of failure in compressive shear. The ability of this system to capture strain concentration zones and to detect initial fracture hours prior to lead formation indicates the potential for predicting areas at high risk for fracture in an on‐ice operational setting.

Robust icephobic nanocomposite coatings with superior abrasion resistance

Icephobic coatings are required for many applications in extremely cold environments, ranging from transport, communications, and infrastructure to energy systems. For practical applications, the ice adhesion strength (IAS) is the most suitable parameter to quantify the icephobicity of a coating, since ice would form on any surface if the conditions are extremely cold. From an engineering view point, an icephobic coating should also be robust, durable, environmentally friendly, and easy to apply over large and complex surfaces at a low cost. Here we report an epoxy based icephobic nanocomposite coating with the typical robustness of epoxy and an IAS as low as 9 ± 3 kPa. The superior icephobicity is provided by the incorporation of silane modified graphene nanoplatelets. Three different silanes are selected based on their low surface energy and their icephobic performance is discussed. The nanocomposite coatings are not only hydrophobic but also their low surface energy have allowed the IAS to be decreased dramatically, below the natural ice detachment threshold. The extraordinary robust icephobic nanocomposite coating reported herein remained icephobic after severe damage through abrasion. This study has demonstrated the potential use of low surface tension silanes for the development of highly robust icephobic coatings to be used in harsh and extreme cold environments.

Product development of ice cream stick from raw banana powder.

This research was focused on using raw bananas in place of natural wooden ice cream sticks. The raw bananas were used in a powdered form and then processed to create a substitute for the wooden sticks. A research operation was carried out, experimenting with different proportions of banana powder in a randomized complete block experimental design (RCBD). The properties of interest for the ice cream sticks were hardness, fracturability, and aw of samples, as well as a sensory evaluation. The research showed that ice cream sticks which contained 50-80% raw banana powder with 40% sugar and 40min of baking resulted in a product with the properties of commonly used wooden ice cream sticks, and that the product also had a good appearance along with positive consumer response. In addition, the maximum shelf life of such ice-cream sticks was 8days. In the future, development of this product can increase the value of bananas and also reduce the waste of single-use wooden ice cream sticks.

Research on the Possibility of Smart Wearable Devices in Ice and Snow Sports Based on Wireless Network

Ice and snow sports are very popular fashion sports in the world. The development of ice and snow sports in China is affected by factors such as climate and natural environment, industrial development, consumption concept, and ice and snow culture. With the advent of the intelligent era, technology has developed rapidly, and the emergence of smart wearable devices has been widely used. The article is based on the recognition of ice and snow movement status, combined with wearable technology, signal processing technology, wireless communication technology, using acceleration sensors, biosensors, bluetooth modules, smartphones, and back-end servers to build a “wearable health monitoring based on recognition of the status of human ice and snow movement system.” Through the daily wear test, on the basis of real-time recognition of the human body motion state, the system issues alarms for dangerous fall actions and abnormal physiological signals in different motion states and can use energy management strategies to save system energy according to the user status, which proves reliability of wearable health monitoring architecture based on human motion state recognition. The paper firstly reviews the related works and literatures of ice and snow sports and smart wearable equipment at home and abroad through literature search and web search and uses questionnaire survey, logic analysis, and interview method to study the development of ice and snow sports. It is feasible to go to the snow and ice. Among them, the proportion of people who think it is expensive is the highest, reaching 65%.

Climate Benefits of Cleaner Energy Transitions in East and South Asia Through Black Carbon Reduction

The state of air pollution has historically been tightly linked to how we produce and use energy. Air pollutant emissions over Asia are now changing rapidly due to cleaner energy transitions; however, magnitudes of benefits for climate and air quality remain poorly quantified. The associated risks involve adverse health impacts, reduced agricultural yields, reduced freshwater availability, contributions to climate change, and economic costs. We focus particularly on climate benefits of energy transitions by making first-time use of two decades of high quality observations of atmospheric loading of light-absorbing black carbon (BC) over Kanpur (South Asia) and Beijing (East Asia) and relating these observations to changing energy, emissions, and economic trends in India and China. Our analysis reveals that absorption aerosol optical depth (AAOD) due to BC has decreased substantially, by 40% over Kanpur and 60% over Beijing between 2001 and 2017, and thus became decoupled from regional economic growth. Furthermore, the resultant decrease in BC emissions and BC AAOD over Asia is regionally coherent and occurs primarily due to transitions into cleaner energies (both renewables and fossil fuels) and not due to the decrease in primary energy supply or decrease in use of fossil use and biofuels and waste. Model simulations show that BC aerosols alone contribute about half of the surface temperature change (warming) of the total forcing due to greenhouse gases, natural and internal variability, and aerosols, thus clearly revealing the climate benefits due to a reduction in BC emissions, which would significantly reduce global warming. However, this modeling study excludes responses from natural variability, circulation, and sea ice responses, which cause relatively strong temperature fluctuations that may mask signals from BC aerosols. Our findings show additional benefits for climate (beyond benefits of CO2 reduction) and for several other issues of sustainability over South and East Asia, provide motivation for ongoing cleaner energy production, and consumption transitions, especially when they are associated with reduced emissions of air pollutants. Such an analysis connecting the trends in energy transitions and aerosol absorption loading, unavailable so far, is crucial for simulating the aerosol climate impacts over Asia which is quite uncertain.

Renewable vs fossil fuel: How a fossil-fuel powered industry pushed a renewable resource out of the ice market in the nineteenth and early twentieth centuries

Artificially produced ice replaced natural ice as a cooling agent in a process of displacement that lasted several decades. This article uses the German market as an example to identify the three main factors that underpinned this process. First, it argues that the displacement process was largely driven by marketing and image campaigns created by the proponents of artificial ice-making technology, together with the general technophilia that prevailed in Imperial Germany. Second, the article shows how Europe's last major cholera outbreak in Hamburg was utilised to promote the transition from natural to artificial ice, and how public opinion and established knowledge disseminated by public authorities were by no means aligned, with natural ice – particularly imported Norwegian natural ice – becoming a victim of adverse public opinion. Third, the article explains why the fisheries, notably the developing steam trawling industry, which was a major and large-scale industrial user of ice in Germany, continued to use natural ice for a relatively long time regardless of public opinion and any perceived pollution of the ice. Rather, decisions to switch from natural to artificial ice in the fisheries were informed by economic and pragmatic reasoning.