Search

Introduction: Improving students' experiences in courses has always been important; one important method for facilitating discussions is an effective icebreaker activity. Statement of the Problem: The move to remote learning during the COVID-19 pandemic presented new challenges for fostering connections among students. Given the constraints in remote learning, teachers need effective and feasible ways to improve student experiences. Literature Review: We reviewed traditional icebreaker activities and highlighted the potential for implementing the Fast Friends procedure in a remotely delivered synchronous class. This procedure involves a discussion guided by a series of increasingly intimate questions meant to enhance connection between unacquainted people. Teaching Implications: Undergraduate and graduate students reported having a positive experience and building connections from the procedure, including enhanced classroom motivation. We share materials so interested readers and teachers can easily implement this. Conclusion: The Fast Friends procedure is a promising icebreaker activity to include at the start of the semester that can help students have a positive experience and build connection with classmates. [ABSTRACT FROM AUTHOR]

For ships navigating in ice floe fields, ship-ice-wave interactions may affect ship performance and ice impact forces. This paper presents an approach to evaluate the cross-coupling added mass and hydrodynamic damping between a passing ship and a free-floating small/medium size ice floe based on the boundary element method (BEM). The influences of added mass and hydrodynamic damping are explored for different wave frequencies and headings. Results are presented for a regular waves scenario whereby a tanker progressing at a slow speed is passing by a free-floating ice floe modeled as a round disk. Radiation and diffraction potentials of the interacting floating bodies are linearly superimposed to reflect the influence of hydromechanical coupling on responses. Parametric analysis of response amplitude operators (RAOs) indicates that the cross-coupling terms of added mass and hydrodynamic damping are of the same order of magnitude as those of the ice floe but smaller by one or two orders of magnitude than those of the ship. It is concluded that hydrodynamic interactions primarily influence the motions of the ice floe and are significant attributes in terms of suitably idealizing ship-ice system dynamics. [ABSTRACT FROM AUTHOR]

This research was conducted to study length–weight relationships (LWR) and condition factors of six Antarctic notothenioidei fish species including blackfin icefish (Chaenocephalus aceratus), single-angle icefish (Chionodraco hamatus), marbled rockcod (Notothenia rossii), black rockcod (Notothenia coriiceps), emerald rockcod (Trematomus bernacchii), and dusky rockcod (Trematomus newnesi) from the King Sejong Station on King George Island and Jang Bogo Station on the Northern Victoria Land. A total of 232 specimens were collected by fishing on the icebreaking research vessel ARAON from December 2020 to February 2021. The LWR parameters and condition factors differed depending on species, which can be affected by their distribution, species characteristics, and gravidity status. The exponent b values in LWR (W = aLb) ranged from 2.593 to 5.184. Four species including C. aceratus, C. hamatus, N. rossii, and T. bernacchii followed positive allometric growth, T. newnesi followed negative allometric growth, and only N. coriiceps showed isometric growth. These results can be helpful in understanding the ecological and growth conditions of six fish species living in the Antarctic Ocean, providing more information for future research on Antarctic fish. [ABSTRACT FROM AUTHOR]

To investigate the driving safety of vehicles travelling on bridges which cross the sea in cold regions, this study presented a dynamic analysis framework for a vehicle–bridge–soil interactive system subjected to stochastic ice loads. Time histories of the stochastic ice loading based on real ice loading spectrum were obtained to consider them as external forces inputs to the vehicle–bridge–soil interaction model. Dynamic responses of a five-span continuous box-girder bridge seated on pile-type foundations under twelve 12-DOF truck vehicles moving are investigated. These numerical analyses revealed that both the bridge and vehicle vertical responses were little affected by lateral ice loads, although their lateral responses were dominated by ice loads. For vehicle driving safety, the front axle tires were more prone to sideslip accidents than rear axle tires were: higher vehicle speed, larger ice loading magnitude, and more slippery pavement adversely affected driving safety. Quantitative analysis was also done using the present dynamic analysis framework. In the worst case studied herein, the front axle tires approached sideslip status, with only 5 kN sideslip force resistance. [ABSTRACT FROM AUTHOR]

Sludge from the wastewater treatment plant of the Argentinean Navy icebreaker ship "Almirante Irizar" was used as inoculum for biohydrogen production. The bacterial community was monitored throughout the fermentation, by sequencing 16S rRNA amplicons, to establish the microbial dynamics of the bioreactor over time. The established operating procedure assured a hydrogen content, along the process, in the range of 59.2–70.0%. The predominant species found were Clostridium sensu stricto and Sporolactobacillus sp. Clostridium showed higher values in the beginning of the fermentation with more than 90% of relative abundance. Conversely, Sporolactobacillus reached values close to 20% at its end. Additional topics discussed are the role of lactic acid bacteria in fermentative biohydrogen production systems and a series of in-process parameters that would allow control of this population. The results obtained allow supporting the use of this type of sludge as a source of hydrogen-producing bacteria. [ABSTRACT FROM AUTHOR]

Ice disasters, such as ice storms, can cause serious damage to power systems. To understand ice disasters' influences on power systems, this paper introduces a resilience evaluation frame for transmission and distribution systems during ice disasters. First, we built a vulnerability model for transmission and distribution systems under ice disaster weather. Then, we established an optimal load power shedding model for transmission and distribution systems. After this, according to the vulnerability model and the optimal power load power shedding model, we generated the fault scenario set of a system in the influence of an ice disaster. According to the curve of system resilience, we propose two resilience evaluation indices of transmission and distribution systems under ice disaster weather. Finally, we verified the efficacy and rationalization of the established resilience evaluation framework with an example in which a transmission and distribution system is coupled with a six-bus transmission system and two distribution systems. This study highlights the necessity of resilience assessment of transmission and distribution systems during ice disasters. [ABSTRACT FROM AUTHOR]

As the most promising alternative to internal combustion engines (ICEs), electric vehicles (EVs) have an excellent development outlook. The charging route scheduling of EVs can simultaneously affect traffic congestion in the transportation network (TN) and power flow distribution in the power distribution network (PDN). The research on TN and PDN coupling networks based on the static traffic flow model is relatively mature; however, it ignores that the traffic flow will spread across periods in a short scheduling period. In this paper, a semi‐dynamic traffic flow model is proposed to represent the dynamic propagation characteristics of EVs and ICEs flow. Furthermore, the cost of carbon emission and system operation are combined as the overall goal of system optimisation. Since the model has become a more complex non‐linear model, this paper proposes to combine the heuristic sequential boundary tightening and binary expansion method to linearise the model. The study compared four cases and found that a 20% penetration rate of EVs can reduce carbon emissions by 4.2% while reducing the system's total cost by 10%. Moreover, the impact of network congestion on the spatiotemporal distribution of traffic flow and power flow in the coupled network is alleviated. [ABSTRACT FROM AUTHOR]

With the effects of global warming, the North Sea Route has become an economic option for cargo transportation because of the shorter distance between East Asia and Europe. Generally, conventional mechanical propulsion systems installed in icecapable tankers suffer from significant drawbacks because of poor fuel efficiency when sailing at low speed, therefore, advanced technologies have been applied such as diesel electric and nuclear-powered propulsion; however, drawbacks still exist. Hybrid propulsion is a more environmental-friendly, economical solution for ships with icebreaking capability, which can address the drawbacks in both diesel electric and nuclear power systems. In this paper, modeling of system components is presented and implemented inMATLAB Simulink. A primary control strategy is applied to the system to ensure system stability, and an advanced secondary strategy is developed and applied to the power sources to minimize fuel consumption. Given two scenarios, the simulation results of the hybrid propulsion systemdeveloped in this research and those of diesel electric propulsion systems with DC and AC distribution systems are compared and indicate that the hybrid system can offer up to 22.4% fuel savings over iceloading condition, and 39.5% fuel reduction over the particular voyage of varying speed in open water is applied in this paper. [ABSTRACT FROM AUTHOR]

Knowledge of the larval ecology of winter‐spawning fish from the Estuary and Gulf of St. Lawrence, Canada, remains scarce due to the seasonal ice cover that prevents ichthyoplankton sampling using conventional methods. Two winter‐spawning species, Atlantic halibut (AH, Hippoglossus hippoglossus) and Greenland halibut (GH, Reinhardtius hippoglossoides), support the most important groundfish fisheries of this area. In March 2020, the authors captured 10 halibut larvae ranging in size from 5 to 14 mm during an opportunistic survey in the GSL onboard an icebreaking vessel. Of these, eight were AH and two GH. Judging by their very small size, the larvae were only a few days old, suggesting that the spawning grounds are close to the capture sites. This effort constitutes a first step in validating the putative spawning areas for these two important GSL stocks. This knowledge is important for the conservation and sustainable management of these fisheries. [ABSTRACT FROM AUTHOR]

To investigate the running safety threshold of trains on the Sichuan-Tibet Railway bridges under the floating ice impact loads, a train-track-bridge dynamics model is established based on the theory of the train-track-bridge dynamic interaction and the design method of tuned mass damper (TMD), which uses the fluid-structure coupling method to calculate the floating ice impact loads. Taking a 5 × 32 m typical simply-supported beam bridge on the Sichuan-Tibet Railway as an example, the critical train speeds corresponding to floating ice impact loads of varying intensity are evaluated, and the effect of TMD on the running safety of the trains under extreme ice loads is investigated. The results show that the fluid effect has a significant influence on the impact loads of ice hitting the bridge pier, which cannot be ignored in the calculation. The ice impact intensities significantly reduce the train's safe speeds. Under the action of floating ice impact loads, the TMD attached to the bridge can effectively reduce the train's derailment factor and wheel unloading rate. The greater the TMD mass ratio, the more pronounced the vibration control effect. [ABSTRACT FROM AUTHOR]

Background: The international community has shown increasing interest in the Arctic and Antarctic due to the value polar regions have in terms of environmental research, natural resources, and national defense. The US Government maintains several permanent research and military facilities in polar regions. Medical evacuation (MEDEVAC) from these facilities can be limited for prolonged periods of time due to their extreme climates. Published data regarding MEDEVACs from these facilities is extremely limited. Methods: Evacuations on military aircraft registered in the Transportation Command Regulation and Command and Control Evacuation System (TRAC2ES) database in a previously de-identified dataset were queried for events from McMurdo, Antarctica. The data was analyzed to determine the number of evacuations, reasons for evacuation, and additional demographic data. Results: There were 31 evacuations from McMurdo Station and Scott Amundsen South Pole Station for 29 unique patients recorded in the available TRAC2ES dataset. Reasons for evacuation included traumatic brain/ head injury, behavioral health concerns, extremity injuries, pregnancy, and various other medical/surgical concerns. Conclusions: MEDEVAC was typically required for advanced diagnostic/treatment modalities or if a patient could no longer fulfill his/her duties. Most evacuations were not directly related to environmental exposure. Given the climate in polar regions can preclude timely evacuation for large periods of time, the need for evacuation must be anticipated and mitigated whenever possible. Better data is needed to guide staffing and mission planning in this remote location. [ABSTRACT FROM AUTHOR]

Similarly, researchers in Canada observed belugas that avoided ice-breaking vessels and altered their behavior for several days. The subcommittee acknowledged that previous work to reduce underwater noise had not succeeded, and approved a work plan to revise the 2014 guidelines and develop comprehensive next steps to better reduce underwater noise from shipping. This can include mandatory noise reduction management plans for ships, setting quantitative noise targets for ships to meet, and onboard monitoring of ship noise to enable real-time adjustments. [Extracted from the article]

Over the years, many publications have been published on planning ship's passage through the NSR and input and output data modeling. Results were not considered in terms of errors of modeled output data. Basic research for the years 2008 - 2020 was carried out in the study on opening and closing dates of ice-free transit corridor on the NSR and probable number of tariff zones where paid assistance of icebreakers would be required. Mathematical relationships of average values and probable errors of navigational, ecological and economic ship voyage performance were developed. For this purpose, partial derivatives of functions were used. The outcomes of the study have shown that changes of total average cost of vessel's transit voyage depends mostly on number of tariff zones where assistance of icebreakers is required. But navigation with icebreakers assistance ensures smaller standard deviation of total voyage time and thus more precise scheduling of ship's voyage timetable through the NSR. The higher probability of meeting requirements set by decision-maker when planning a long-term voyage of ship, the shorter time window for meeting these requirements. Outside the favorable time window, the navigational, ecological and economic results of voyage deteriorate very quickly. [ABSTRACT FROM AUTHOR]

The rapidly increasing concentrations of carbon dioxide lead to a threat of global climate change. As one of the major sources of carbon emissions in the Antarctic region, shipborne tourism in the Antarctic is expanding rapidly. Consequently, the carbon emissions of shipborne tourism in Antarctica are rapidly increasing. However, there is not enough attention being paid to this issue. In this paper, a calculation model was established to calculate the carbon emissions of cruise ships from the 2003/04 season to the 2016/17 season. The evolution of the carbon emissions from Antarctic cruise ships was described. An aggregate energy efficiency index was developed to evaluate the energy efficiency performance of Antarctic vessels. The key drivers were analyzed to find the paths of carbon reduction. The results show that: (1) The emissions per passenger-trip did not show a downward trend. The total carbon emissions increased continuously with the increasing number of tourists. The total carbon emissions in the 2016/17 season was double that in the 2003/04 season. (2) The aggregate energy efficiency index of Antarctic tour vessels has not reached an advanced level yet. It is the main reason for the high value of emissions per passenger-trip. (3) Due to the oversupply of Antarctica tour ships, there is a low rate of occupancy, which accounts for the decline in aggregate energy efficiency from the 2014/15 season to the 2016/17 season. This study suggests that the administrators of Antarctica should strengthen supervision of the tourism market, control the rapid growth in the number of cruise ships, improve the aggregate energy efficiency of cruise ships and form an efficient and green Antarctic tourism management system. [ABSTRACT FROM AUTHOR]

Icebreaker assistance is a common yet intricate operation in ice-covered waters, frequently leading to collisions between ships and icebreakers. This underscores the need for advanced kinematic models to improve safety and coordination in convoy operations. Consequently, this paper introduces a kinematic model for guiding intelligent ships under icebreaker assistance. The model, grounded in the Traffic Factor State Network (TFSN), evaluates the safety state of a fleet in various ice conditions, using data from actual convoy operations. An enhanced Proportional Integral Derivative (PID) algorithm is integrated to formulate a multi-ship following model, which accounts for the kinematic characteristics of ships in ice. The model also incorporates the transmission process of ship maneuvering commands. Its validity is confirmed through application to two ships under icebreaker assistance. The findings show that the model effectively simulates safe speeds and maintains proper inter-ship distances over time, and it generates safe kinematic instructions for the fleet. This model may contribute to navigational safety in ice-covered waters and demonstrates the potential for inclusion in ice navigation support systems. • The paper introduces a kinematic model for the collaborative operation of multiple ships. • This method is grounded in the evaluation of kinematic features of ships in various ice conditions. • The effectiveness is illustrated through actual convoy operations in the Baltic Sea. • The proposed approach has the potential to support intelligent decision-making systems. [ABSTRACT FROM AUTHOR]

To optimize the scheduling scheme of tramp vessels between Asia and Europe, considering the opening of the Arctic route, a vessel scheduling management optimization model is developed from the perspective of shipping companies. Based on meeting the shippers' requirements for transportation between Asian and European ports, minimizing the total cost of multi-period operation of tramp vessels, the specific transport scheduling scheme for ships is obtained. We found that shipping companies building their Vessels with Ice-breaking Ability (VIA) can reduce the total cost of ships operating Asia-Europe routes throughout the year. Furthermore, in the event of a half increase in fuel prices, opting for Arctic routes during the winter season proves to be more cost-effective for shipping companies. • This paper studies the tramp vessel scheduling of the NSR/SCR. • Building vessels with or without ice-breaking ability is considered. • A nonlinear integer programming model is proposed. • A linearization method is developed. • A case study is conducted to analyze the studied problem. [ABSTRACT FROM AUTHOR]

Ships and offshore structures operating in ice-covered waters need to be able to break ice. The hulls of ships and offshore structures are often designed to be inclined so that an out-of-plane force can be incurred to initiate flexural failure. During this process, an in-plane force co-exists as the result of the hull inclination, which can affect the bending process and alter the magnitude of interaction force. Additionally, the loading process can be rapid and incur dynamic effect within the ice sheet, resulting in higher peak loads compared to the scenario of quasi-static loading. The effect of in-plane force and loading speed, however, are often neglected in the modelling of the icebreaking process in order to enable simplified solutions of analytical form, which leads to deviations in the estimation of ice loads. This paper aims to investigate the effects of in-plane force and loading speed on the ice bearing capacity during the icebreaking process. This is conducted via the Finite Element Analysis (FEA) with the Cohesive Element Method (CEM). An anisotropic beam analogy concept is proposed to model a 3D ice wedge with a 2D beam which has varying properties along the axial direction. The analogy enables fast and stable simulation of ice crack propagation through its thickness direction, while maintaining properties of the ice wedge in 3D. The analogy is verified with Nevel's closed-form solution for a narrow wedge resting on an elastic foundation. After that, the beam is loaded with a rigid wall with different inclination angles and loading speeds. The results reveal that the in-plane force and loading speed have significant influence on the icebreaking process, resulting in different bearing capacity and overall energy consumption. Based on the numerical results, a regression study is conducted to derive a correction coefficient accounting for the joint effect of in-plane force and loading speed on the bearing capacity, which can be incorporated into ice-structure interaction simulation models. • An anisotropic beam analogy is proposed to model 3D ice wedge with 2D beam to investigate ice wedge bearing capacity. • The joint effect of the in-plane force and the loading speed on the bearing capacity of the ice wedge is investigated. • A strong coupling effect between the in-plane force and the loading speed exists, which jointly affect the bearing capacity. • A regression formula is obtained to account for the joint effect of in-plane force and loading speed on bearing capacity. [ABSTRACT FROM AUTHOR]

With the increasing number of ships navigating in polar regions, collisions between ships and sea ice are inevitable. The cabin noise problem caused by ship-ice collisions is significantly different from that of ships navigating in open water, and it seriously affects the comfort and safety of shipboard personnel. To explore the transient cabin noise response caused by ship-ice collisions, this paper performs numerical studies of the ice load, compares the ice resistance values of experimental and empirical formulas through the ship-ice-water‒air coupled collision method, and gives the sound source load excitation. Then, in the frequency domain acoustic analysis, the acoustic response of the typical cabin noise under icebreaking excitation and coupling excitation is calculated by using the acoustic-structure coupling analysis model and statistical energy analysis model, respectively. The effect of ship transient cabin noise on personnel comfort is analyzed according to the standard of ship noise. The results show that the transient cabin noise is scattered from the collision position to the stern at a certain angle and decays along the length, width, and superstructure of the ship as the frequency increases. The transient cabin noise under coupled excitation shows an M-shape distribution in the ship ranges. The icebreaking excitation mainly affects the transient cabin noise within 1000 Hz, with strong nonlinearity at a low-frequency band. The sound source excitation has a more obvious effect on the cabin noise in the middle-high frequency bands. The A-weighted sound pressure level of transient cabin noise in accommodation cabins and wheel houses during icebreaking operations of polar ships exceeds 5–20 dB(A) of the standard limit, which seriously affects the comfort of people on board. The research results of this paper can provide a reference for the study of ship-ice collision-induced transient cabin noise and the formulation of relevant standards. [ABSTRACT FROM AUTHOR]

This is a correction to: Irene Rocchi, Alice Tomassini, Matteo Masotta, Maurizio Petrelli, Mónica Ágreda López, Sergio Rocchi, Textures and Chemistry of Crystal Cargo of the Pleiades Volcanic Field, Antarctica: Potential Influence of Ice Load in Modulating the Plumbing System, Journal of Petrology, Volume 65, Issue 4, April 2024, egae027, https://doi.org/10.1093/petrology/egae027.This article has been updated to correct the presentation of author first and family names. [Extracted from the article]

When a ship navigates in ice-covered areas, its hull experiences motion and vibration responses due to ship-ice contact. The magnitude of such responses can be represented well by acceleration, which is easy to measure onboard ice-going ships. The level of acceleration is determined by the environmental and operational conditions through excitation via the ship-ice contact. Conversely, it is possible to infer excitation and environmental conditions using acceleration measurements via appropriate methods. Accelerations associated with such responses can also affect the functionality of the onboard equipment and therefore, should be quantified. Nevertheless, studies on shipborne acceleration measurements in ice fields and their links to prevailing excitations and environmental conditions are rare. This study explores the feasibility of using shipborne acceleration measurements to infer the corresponding excitations (i.e., ship-ice contacts) as a first step towards the inference of ice conditions via acceleration measurements. An automatic identification method for ship-ice contact is proposed that can effectively separate ship-ice contact events from acceleration measurement signals. The acceleration signals are decomposed in the time-frequency map obtained through a short-time Fourier transformation (STFT). An improved detection transformer (DETR) model was used to automatically identify ship-ice contact events and achieved good accuracy in the validation set. This model was then applied to automatically identify ship-ice contacts using acceleration signals under various environmental and operational conditions. The frequency of the identified ship-ice contact reasonably reflects its dependence on prevailing environmental and operational conditions, which confirms the validity of the proposed methodology. • A novel concept is proposed to identify ship-ice contacts from onboard acceleration measurements. • An improved DETR model is applied to the time-frequency map obtained by STFT. • The DETR model is applied to various ice conditions and the ship-ice contact frequencies is analyzed. • Study quantifies ship speed and ice concentration impact on ship-ice contact frequency. [ABSTRACT FROM AUTHOR]

The Northern Sea Route (NSR) is perennially ice-covered. As shipping demand increases, the inherent theoretical following model is difficult to describe the increasingly complex ship-following behavior under icebreaker escort operation. This paper aims to establish an innovative model, employing a hybrid approach that integrates theoretical principles and data-driven methodologies. Key factors of sea ice, such as the thickness and density, are comprehensively considered. The model's foundation is grounded in a backward-looking velocity difference framework, accounting for the motion states of preceding and trailing ships. This framework guides the design of the data-driven model, enhancing its interpretability. A deep learning-based long short-term memory network is employed to formulate a ship-following model, tailored to the challenging ice-infested regions. Moreover, an attention mechanism is introduced to augment the model's capability to focus on and extract critical information from the input sequences of ship-following behaviors. A case study including two-ship and multi-ship following scenarios demonstrates good model performance with a mean absolute percentage error (MAPE) of less than 2 %. This research brings an important advancement for predicting ship-following behaviors in the NSR, which could be used to enhance navigation safety and efficiency in the Arctic region. • A ship following model is proposed to improve navigation safety and efficiency in the NSR. • Theory-driven and data-driven approaches are combined in the proposed model. • Ship speed and course during formation are identified in ice-covered waters. • Case studies in two ships and multi-ships scenarios are conducted to verify the model strength. [ABSTRACT FROM AUTHOR]

The Finnish-Swedish winter navigation system plays an essential role in logistics to the ports surrounded by frozen sea in winter. Coordination of icebreakers is crucial to guarantee sufficient transit speed of merchant ships and minimize the waiting time. Simulation of the winter navigation system provides the opportunity to optimize the system performance and help the planning of future icebreaker fleets. For simulation, estimation of ship performance, such as the actual speed in ice, is essential. Calculation methods to estimate ship performance in such contexts are typically required to be of simple form without the need for heavy computation. Existing ship performance models embedded in route optimization algorithms and winter navigation simulations in the literature are often oversimplified. This paper proposes a systematic ship performance modelling approach which accounts for a wide range of parameters, such as ice condition and parameters, power variation and icebreaker assistance. The approach is validated against real ship voyages. The proposed approach is implemented into a simulation model which simulates the operation of merchant ships and icebreakers on the Baltic Sea. Analyses are conducted on the system level in terms of the waiting time of merchant ships needed for icebreakers as well as the energy consumption. • The coordination of icebreaker operations is crucial to guarantee sufficient traffic flow of merchant ships. • This provides the opportunity to optimize the system performance and help the planning of future icebreaker fleets. • For such simulations, estimation of ship performance, such as the actual speed in ice, is essential. • A ship performance modelling approach accounting for ice condition, power variation and icebreaker assistance is proposed. • The approach is implemented in a winter navigation simulation model to simulate operation of merchant ships and icebreakers. [ABSTRACT FROM AUTHOR]

Maneuverability is a critical aspect of ship navigation performance, particularly during polar navigation, where the presence of ice significantly affects maneuverability compared to open water navigation. By coupling the non-smooth discrete element method (NDEM) with the Maneuvering Modeling Group (MMG) model, this paper proposes a numerical model to simulate the maneuvering motion of full-scale ships in broken ice regions. In the proposed model, the ship-ice interaction was solved through NDEM, while the 3-DOF MMG model was utilized to simulate the autonomous navigation movement of ships. Based on the relationship between ship turning radius and ship speed, the critical relationship between ice moment and ice resistance is derived in this paper, which can be used to verify the rationality of simulation results of maneuvering motion. In addition, the effects of ice concentration, size, thickness, and ship speed and rudder angle on the ship's maneuvering trajectory and steering flexibility are analyzed by simulating turning motion and Zig-Zag maneuvers. This provides an effective numerical model to simulate the maneuvering motion of a ship in a broken ice area with low-medium ice concentration. • A NDEM-MMG numerical coupled model is proposed to effectively simulate maneuvering motions of ships in broken ice areas. • The ice moment and resistance critical relation is derived to judge the change of ship's turning range in broken ice areas. • By simulating the turning and Zig-Zag motions, the effects of ice floes on ship's maneuvering performance have been analyzed. [ABSTRACT FROM AUTHOR]

The capability of an icegoing ship to break out from an ice channel is a main index of its manoeuvrability in ice. Breakout is necessary if a ship needs to change its course when sailing in an ice channel. Breakout can also be used as an evasive action to avoid collision with the leading ship in emergencies during escort and convoy. Although the ice channel breakout test is documented in ITTC guidelines as a standard manoeuvring test, little data is available on the performance of icegoing ships in this context. This paper presents model-scale tests carried out at Aalto Ice Tank with a double-acting vessel with podded propulsion. Parameters including ice thickness and strength, ice channel width, initial speed and propulsive settings are varied between the tests to examine their influence on the capability and distance to break out from ice channels. In addition, stopping tests by reversing propeller revolution were conducted in ice channels to benchmark the breakout operation as an option to avoid collision. The test results reveal the influence of multiple factors on the ship's channel-breakout capability, including channel width, shaft power, initial speed, as well as thickness and strength of ice. With additional complementary numerical simulations at high speeds, it is found that for collision avoidance braking is more efficient at low speed and breakout at high speed. Recommendations on breakout test in model scale are given based on the lessons and experience learnt from the experiments. • Ice channel breakout model-scale tests were carried out at Aalto Ice Tank. • Numerical simulations were simulated to compare with and supplement model tests. • Parameters are varied to study their influences on the ice channel breakout capability. • Ice channel braking is more efficient at low speeds and breakout at high speeds for collision avoidance. • Recommendations on ice channel model-scale tests are given. [ABSTRACT FROM AUTHOR]

In-flight ice accretion may possibly jeopardize the safety of fixed- and rotary-wing aircraft. Icing can possibly occur if supercooled water droplets in clouds impinge on the aircraft surfaces and freeze upon impact. It may result in instrument failures and degradation of the aerodynamic performances. A major problem related to ice accretion is the possibility of ice shedding from the main body and impacting other parts of the aircraft or being ingested by the engines. In fixed-wing aircraft, shedding is caused by the action of the aerodynamic forces or the activation of an Ice Protection System. In the present work, a multi-physics framework is presented to simulate ice accretion and shedding from wings and engine nacelles. The aerodynamics is computed using the open-source toolkit SU2 (Economon et al., 2015) [1]. Cloud droplet trajectories are computed using the arbitrary-precision Lagrangian in-house solver PoliDrop. Then, the in-house ice accretion toolkit PoliMIce (Gori et al., 2015) is used to determine the ice layer. An algebraic level-set approach with iterative volume mesh refinement has been developed to extract the ice shape from the iced wing geometry. A FEM structural analysis is performed on the accreted ice shape by means of the open-source code MoFEM (Kaczmarczyk et al., 2014, 2020) [2]. Internal stresses within the ice geometry due to aerodynamic forces are computed. Three-dimensional ice accretion simulations are performed to check the validity of the present approach. [ABSTRACT FROM AUTHOR]

The Arctic has become an important region due to the possibility of access to hydrocarbon resources and the formation of strategic maritime routes as a result of climate change. In this context, China published its policy document "White Paper" in 2018, expressing its intentions and aspirations about the Arctic. With this document, China has defined itself as a "near Arctic state" and aimed active participation in the Arctic issues. China, which deals with scientific research on the Arctic and the development of Arctic ports and transport corridors, emphasizes the importance of the "Polar Silk Road" as a part of the "Belt and Road Initiative". In doing so, China develops strong diplomatic relations with the Arctic states, enabling new dimensions to the geopolitics of the region. China's recent construction of icebreaker ships proves that it has longterm plans to become an "Arctic Power". This article analyzes whether China's Arctic goal is limited to access to the region or becoming a powerful actor with a decisive role in the region. The study also focuses on how this situation is perceived among other Arctic states. Finally, this article explores China's Arctic policy, China's interests in the Arctic region and its impacts in the light of the Neorealism Theory. [ABSTRACT FROM AUTHOR]

The Arctic has become an important region due to the possibility of access to hydrocarbon resources and the formation of strategic maritime routes as a result of climate change. In this context, China published its policy document "White Paper" in 2018, expressing its intentions and aspirations about the Arctic. With this document, China has defined itself as a "near Arctic state" and aimed active participation in the Arctic issues. China, which deals with scientific research on the Arctic and the development of Arctic ports and transport corridors, emphasizes the importance of the "Polar Silk Road" as a part of the "Belt and Road Initiative". In doing so, China develops strong diplomatic relations with the Arctic states, enabling new dimensions to the geopolitics of the region. China's recent construction of icebreaker ships proves that it has longterm plans to become an "Arctic Power". This article analyzes whether China's Arctic goal is limited to access to the region or becoming a powerful actor with a decisive role in the region. The study also focuses on how this situation is perceived among other Arctic states. Finally, this article explores China's Arctic policy, China's interests in the Arctic region and its impacts in the light of the Neorealism Theory. [ABSTRACT FROM AUTHOR]

Main problem for scheduling vessel transit voyages through the Northern Sea Route is the difficulty in predicting distribution of ice boundaries in regions that cannot be overcome by individual ice classes of vessels. Scheduling of voyage is related to speed that vessels can develop and moment of time when vessels will be able to commence and complete passage safely through areas that are main obstacle and are blocking longest transit passage through the Northern Sea Route. This applies to voyages carried out by vessels navigating on their own and with support of icebreakers. Additional problem is lack of consistency of content of maps of ice cover, which can be used for vessels voyage planning through areas where ice cover occurs. Results of this research on influence of uncertain information related with time window of conditions favorable for navigation of vessels of different ice classes on schedule of theirs voyage on example of summer navigation season 2017 are presented in this work. [ABSTRACT FROM AUTHOR]

Ice often complicates shipping in extremely cold regions, leading to energy-consuming, expensive transportation. Ship performance can be significantly improved with icebreaking assistance that uses specialized ships called icebreakers to create navigable pathways in ice fields. Icebreakers are a critical and expensive resource with high energy consumption that must be judiciously utilized for efficient traffic flow. Optimizing icebreaker usage requires careful consideration of multiple factors related to weather, ships, and regulations. The existing decision support tools for icebreaker management primarily aim to minimize the total waiting time of ships, which may result in allocation of excess icebreakers. The paper presents a novel simulation-based approach for decarbonizing shipping in ice by intelligent icebreaking assistance. The proposed approach optimizes icebreaker assistance for both eco- and cost efficiency, allowing for more sustainable icebreaking policies. A case study representing a simplified configuration of the Finnish-Swedish Winter Navigation System demonstrates this approach to come up with alternate operating strategies that can significantly improve the emission and/or cost (e.g., up to 7 percent less greenhouse gas emission or up to 14.2% lower costs). Results show that the proposed approach is promising, for providing recommendations on environmental and economic policies to decarbonize the Finnish-Swedish icebreaking assistance. • Shipping in ice requires more energy and resources and incurs higher costs compared to open water. • Icebreaker management improves safety and efficiency of shipping in ice, while responding to climate-related challenges. • A simulation-based decision-making approach incorporates environmental factor in centralized icebreaker assistance management. • Case study in the Baltic Sea demonstrates reduction of CO 2 emission by 7% and cost by 14% than the baseline configuration. [ABSTRACT FROM AUTHOR]

Ice often complicates shipping in extremely cold regions, leading to energy-consuming, expensive transportation. Ship performance can be significantly improved with icebreaking assistance that uses specialized ships called icebreakers to create navigable pathways in ice fields. Icebreakers are a critical and expensive resource with high energy consumption that must be judiciously utilized for efficient traffic flow. Optimizing icebreaker usage requires careful consideration of multiple factors related to weather, ships, and regulations. The existing decision support tools for icebreaker management primarily aim to minimize the total waiting time of ships, which may result in allocation of excess icebreakers. The paper presents a novel simulation-based approach for decarbonizing shipping in ice by intelligent icebreaking assistance. The proposed approach optimizes icebreaker assistance for both eco- and cost efficiency, allowing for more sustainable icebreaking policies. A case study representing a simplified configuration of the Finnish-Swedish Winter Navigation System demonstrates this approach to come up with alternate operating strategies that can significantly improve the emission and/or cost (e.g., up to 7 percent less greenhouse gas emission or up to 14.2% lower costs). Results show that the proposed approach is promising, for providing recommendations on environmental and economic policies to decarbonize the Finnish-Swedish icebreaking assistance. • Shipping in ice requires more energy and resources and incurs higher costs compared to open water. • Icebreaker management improves safety and efficiency of shipping in ice, while responding to climate-related challenges. • A simulation-based decision-making approach incorporates environmental factor in centralized icebreaker assistance management. • Case study in the Baltic Sea demonstrates reduction of CO 2 emission by 7% and cost by 14% than the baseline configuration. [ABSTRACT FROM AUTHOR]

The Polar Research Vessel (PRV) must consider both icebreaking and ocean navigation performance, but its hull lines can result in large amplitude roll motion in storms. To address this issue, an anti-roll tank (ART) is fitted to restrain the roll. Using the viscous CFD method, a numerical model is established to couple ship motion with fluid motion in the ART. The simulation accurately captures the fluid motion characteristics in the ART and solves the nonlinearity of fluid motion coupled with roll motion. The study reveals the suppression rule of ART parameters on ship motion and completes the design of ART for polar icebreakers. Investigating the effects of water load, channel height, and installation height of ART on roll motion suppression using an equivalent damping evaluation method provides insight into ART parameter suppression rules on ship motion, facilitating ART design for polar icebreakers. • Numerical simulation is effectively carried out for the hull motion coupled with the ART. • The Polar Research Vessel without any hull appendages has a quite small damping coefficient. • The influence of the parameters of the ART on suppressing roll motion can be well judged by equivalent damping. • The effect of vertical height of the ART on roll motion is extremely obvious, while water load and channel height areare lower. [ABSTRACT FROM AUTHOR]

Under severe Arctic ice conditions, escort operations are the most efficient methods for facilitating shipping. Nevertheless, escort operations are among the most dangerous operations, as they may result in icebreaker–ship collisions and/or ship besetting in ice. To mitigate the risk of collisions, it is essential to understand the event sequences of collisions and the risk control options that can be implemented to reduce the occurrence of undesired events. This paper proposes a hybrid causal logic model to estimate the likelihood of an icebreaker–ship collision while considering human factors during an escort operation along the Northeast Passage. The model relies on inputs from four icebreaker captains. Its applicability is demonstrated for a 2018 summer voyage of a cargo ship assisted by an icebreaker. Risk control options are then proposed based on qualitative and sensitivity analyses of the model. The results of this study can assist shipping companies to better understand the sequence of events prior to icebreaker–ship collisions during escort operations in ice-covered waters. This paper provides information on risk reduction measures. In addition, the proposed model can assist in route planning. • A novel model is presented to analyse the icebreaker-ship collision in escort operations. • A captain-verified collision sequence diagram is presented. • Most dangerous events leading to the collision are derived. • Risk control options in escort operations are proposed. [ABSTRACT FROM AUTHOR]

For over four decades, Cold War politics shaped technology and business developments in European and North American military-industrial businesses. However, Matala shows how Finnish businesses navigated Cold War politics to their advantage and gained substantial leverage. Nevertheless, I recommend Matala's book for anyone with an interest in the dynamics between politics, technology, and business during the Cold War. [Extracted from the article]

Most vessels cannot safely sail in areas with sea ice. In the Northern Baltic Sea area, the presence of sea ice often requires icebreaking ships to open up ice-covered areas so merchant vessels can proceed to their destinations. In this environment there is an increasing number of ships. With growing transport volumes in sea ice environments, icebreaker operations such as convoys have become increasingly important to ensure navigation safety. This paper proposes a model of multi-ship following for icebreaker convoy operations in continuous icebreaking conditions, using modelling principles from earlier proposed car following models combined with considerations of safe distance and safe speed in ship convoy operations in ice conditions. The model parameters are calibrated with empirical data from actual icebreaker convoy operations, using data from the Automatic Identification System (AIS) and sea ice model data. The model determines ice resistance according to ice thickness, type, and bending strength, and the main dimensions of the icebreaker leading the convoy. The maximum safe navigable speed is used to assess the following ships' ability to sail in sea ice. The multi-ship following simulation results were found to be in good agreement with empirical data. The new proposed model can provide a theoretical reference for icebreaker convoy operations, can have practical use in ship simulators to improve training, and could be useful for traffic modelling and planning purposes. • A multi-ship following model for icebreaker escort operations is proposed. • Safety distance, safety speed and the effects of sea ice on the operation are accounted for. • Main intended use of the proposed model is for implementation in maritime simulators. • The model parameters are calibrated using empirical data of icebreaker escort operations. • Case studies show good agreement between the simulation model and real-world operations. [ABSTRACT FROM AUTHOR]

Abstract Offshore development and growing prospects of commercial shipping in the Arctic pose the challenge of optimal ship routing in ice. Route selection in spatially distributed ice conditions significantly affects the voyage time and determines the efficiency of shipping. Most of the applied methods of ice routing solve the problem of a single vessel route selection without considering icebreaker support. At the same time, the real practice of ice navigation is closely connected with icebreaker assistance. It allows reducing the voyage time and fuel consumption, while having additional costs for icebreaker services. Such opposite trends set an optimization task that has not been studied in detail before. In this article, we presented the formulation of a Single Vessel and Icebreaker Assisted Ice Routing optimization problem in non-stationary ice conditions. We considered the icebreaker assistance as an integral part of the overall route optimization problem, and used the economic criterion to optimize both ship route and amount of icebreaker involvement. The article contains the adapted mathematical formulations of classical graph-based and wave-based routing problems in order to consider icebreaker assistance. To prove the practical applicability of these formulations, we developed special subject-oriented research software and implemented there both graph-based (Dijkstra, A*) and the wave-based ice routing methods. Using this developments, we conducted several case studies and made the analysis of strengthens and weaknesses of the alternative routing methods in case of ice operation. The results of the study may serve an additional step to the practical implementation of ice routing technologies and planning of icebreaker resources. [ABSTRACT FROM AUTHOR]

Abstract The modelling of the ice failure including icebreaking pattern and ice bearing capacity is an important issue in numerical simulations of ships going through level ice, in order to predict ship performance and ice loads. Previous studies model the shape of ice cusps assuming a simplified geometry, e.g. circular or triangular. According to the observations during full-scale ship trials, the geometry of the ice cusps is more elliptical rather than circular, with larger breaking length at the edges than that at the center. In this paper, a new ice failure model is developed which results in more realistic cusp shapes compared to existing approaches. The model is based on an analytically-derived differential equation, which is solved numerically via the Finite Difference Method (FDM). The predictions of ice cusps geometry are validated against full-scale measurement of ice cusps, obtained with an on-board stereo camera system. Satisfying agreement is shown. The ice failure model is incorporated into a numerical model for the prediction of ship performance in level ice. The predictions are compared with ship speed record obtained from a full-scale trial. It is shown that the model gives reasonable results for ship speed. Highlights • An engineering ice failure model which gives more realistic icebreaking pattern compared to state-of-the-art is proposed. • This model takes various ship and ice related factors into consideration and therefore is physically sound. • The model is integrated into a numerical simulation model for ships performance in level ice. • Ice photos gathered from full-scale test are measured and analyzed to support and validate the model. [ABSTRACT FROM AUTHOR]

Abstract The effects of the unsteady change of the wind direction on the airwake over the helicopter platform of a Canadian Coast Guard polar icebreaker were studied experimentally. By application of particle image velocimetry on a scaled model of the icebreaker, quantitative flow field data were obtained for several rates of change in the wind direction. This study was conducted in a water channel that featured a simulated atmospheric boundary layer as inflow condition. The rate of change in the incidence angle, α ˙ , varied in the range −0.25 ≤ α ˙ L / U ≤ 0.25, where L and U are the characteristic length and velocity, respectively. In addition to the time-averaged velocity fields, the turbulence intensity was evaluated to investigate the unsteadiness of the flow. Increasing the rate of change of the incidence angle of the incoming flow resulted in an increase of the turbulent intensity for all considered nominal incidence angles of the inflow. A notable exception to this trend was observed at α = 60°, where the direction of the inflow change had a pronounced effect on the structure of the flow over the helicopter deck. Thus, negative values of α ˙ L / U resulted in the wake of the superstructure not affecting the flow over the helicopter platform. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Collision accidents between icebreaker and assisted ship in ice-covered waters are investigated. • The collision risk factors are identified and classified according to HFACS-SIBCI model. • The fault tree model is proposed to analyze collision risk factors under icebreaker assistance. • Risk Control Options (RCOs) are formulated to prevent collision accident occurrence in ice-covered waters. Abstract With the global warming and a large amount of sea ice melting, the available Arctic Sea Route has greatly enhanced the value of Arctic shipping. Ship operations under icebreaker assistance have become an essential way to facilitate the safe navigation of merchant vessels sailing through the Arctic Sea Route in ice-covered waters, but they can also put the crew and the ship in danger caused by a possible collision between the assisted ship and the icebreaker. In this paper, a dedicated Human and Organizational Factors (HoFs) model of ship collision accidents between an assisted ship and an icebreaker is developed and analyzed with the aim to identify and classify collision risk factors. First, a modified model of the Human Factors Analysis and Classification System (HFACS) for collision accidents between a ship and an icebreaker in ice-covered waters is proposed, which helps to analyze ship collision reports. Then, a Fault Tree Analysis (FTA) model is utilized to analyze the fundamental collision risk factors according to the statistical analysis of accident reports and expert judgments based on the HFACS-SIBCI model. Finally, qualitative analysis is carried out to analyze collision risk factors under icebreaker assistance, where Risk Control Options (RCOs) are formulated. An important guidance for the risk control of ship collisions during icebreaker assistance in ice-covered waters is provided for lawmakers and shipping companies. [ABSTRACT FROM AUTHOR]