Simple models for ice simulation for hydrotechnical engineering

The mechanical behaviour of ice is a complex phenomenon that is influenced by various factors, such as temperature, loading conditions, and structural geometry. To accurately predict the response of ice structures and estimate ice loads, appropriate models are required. In this article, we have reviewed several widely known material models for ice, including elastic, viscoelastic, plastic, damage, and fracture models. Elastic models are simple and easy to use, but they do not account for the time-dependent behaviour of ice. Viscoelastic models, on the other hand, can predict the evolution of damage and failure in ice structures but can be computationally ex-pensive. Plastic models can simulate the ductile behaviour of ice under high stress but do not account for damage and fracture. Damage models can simulate the evolution of damage and failure in ice structures but can also be computationally expensive. Fracture models can simulate the brittle behaviour of ice and predict crack propagation but require accurate input data. In practice, a combination of models is often used to account for different aspects of ice behaviour. With the advances in computer technology and simulation techniques, it is be-coming increasingly possible to simulate more complex ice structures and loading conditions. This could lead to the development of more accurate and efficient ice models that can be used for a wider range of applications, such as predicting the behaviour of ice structures in response to climate change. The effects of climate change on the behaviour of ice and the resulting impact on infrastructure are a growing concern. Therefore, the development of more accurate and efficient ice models is critical for the sustainable development of these regions

Lagrange Anchor and Characteristic Symmetries of Free Massless Fields

A Poincar\'e covariant Lagrange anchor is found for the non-Lagrangian relativistic wave equations of Bargmann and Wigner describing free massless fields of spin $s>1/2$ in four-dimensional Minkowski space. By making use of this Lagrange anchor, we assign a symmetry to each conservation law and perform the path-integral quantization of the theory

Property rights on the underwater harbour hydrotechnical constructions

The Russian Federation has a large number of seas with access to the world ocean. The logical use of this fact is the development of maritime transport infra-structure as one of the cheapest per unit weight of the transported cargo. It is also worth noting that in some northern remote regions, there are still no alternatives to seasonal sea delivery. In recent decades, Russia has planned the construction and reconstruction of a large number of sea ports, including along the Northern Sea Route (NSR). From the open sources it is known that near the main way on the Northern Sea Route are: Murmansk, Dikson, Tiksi, Provideniya, Petropav-lovsk-Kamchatsky, Vladivostok; and also: Arkhangelsk, Naryan-Mar, Dudinka, Igarka, Khatanga, Pevek, Anadyr; among newly designed and planned / recon-structed: Belokamenka, Utrennii, Bukhta Sever, Tanalau. It is common for all port facilities to have an access channel or other facilities on the seabed. The presence of the facilities on the seabed introduces ambiguity in the owner's responsibilities for maintenance and service, since registration of private ownership of these objects is impossible according to the Russian law

Conjugates of 8-[2,2’-bipyridinyl]coumarins as potential chemosensors for Al3+, Cu2+, Cd2+, Zn2+ ions: synthesis and photophysical properties

In this work, we report the synthesis of novel coumarin-bipyridine conjugates using a sequence of C–C coupling reaction between 5,7-dimethoxycoumarins and 3-pyridyl-6-aryl-1,2,4-triazines followed by the Boger reaction with norbornandiene to obtain 8-[2,2'-bipyridyl]-5,7-dimethoxycoumarins. Photophysical properties were investigated for the obtained series of 8-[2,2'-bipyridyl]-5,7-dimethoxycoumarins: absorption and emission wavelength maxima are in the region of 212–296 and 401–410 nm, respectively; Stokes shifts are up to 116 nm, and fluorescence quantum yields are up to 15.0%. It was found that titrating the conjugates with Al3+, Zn2+, and Cd2+ ions results in an increase in the intensity of the emission maxima of the complexes, while the opposite effect was observed in the case of titration with Cu2+ ions. These findings suggest that the studied compounds may be considered as promising chemosensing materials. Finally, a positive solvatochromism of 8-[2,2'-bipyridyl]coumarins and their metal complexes was established. The experimental data are supported by mathematical calculations according to the Lippert-Mataga equation and Kosower diagram

Expedient synthesis of 1,2,4-triazinyl substituted benzo[c]coumarins via double oxidation strategy

Herein, we report a convenient one-pot synthesis of 1,2,4-triazinyl derivatives of benzocoumarins. The proposed approach consists in the nucleophilic addition of tetrahydrobenzo annulated dimethoxycoumarin to 1,2,4-triazines followed by double oxidation of both dihydrotriazine and tetrahydrobenzo groups with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The nucleophilic addition of the dimethoxycoumarin to 1,2,4-triazines was carried out in the presence of three-fold excess of methanesulfonic acid in DCM at room temperature and take place between positions 4 and 5 of coumarin and 1,2,4-triazine, respectively. The double oxidation step was achieved with 3.6 equivalent of DDQ. Selective oxidation of dihydrotriazine moiety, without affecting the tetrahydrobenzo fragment, was achieved using 1.2 equivalent of tetrachlorobenzoquinone (TCQ). The differences in the oxidation with TCQ and DDQ appear to be related to the higher oxidative potential of DDQ in contrast to TCQ. The advantages of the method are the elimination of the use of transition metals, the availability of starting materials, and the simplicity of the procedure. The proposed approach provides a two-step one-pot protocol for the synthesis of triazinyl benzocoumarins, precursors for the preparation of push-pull pyridinyl chromophore

MeV-range velocity-space tomography from gamma-ray and neutron emission spectrometry measurements at JET

We demonstrate the measurement of a 2D MeV-range ion velocity distribution function by velocity-space tomography at JET. Deuterium ions were accelerated into the MeV-range by third harmonic ion cyclotron resonance heating. We made measurements with three neutron emission spectrometers and a high-resolution γ-ray spectrometer detecting the γ-rays released in two reactions. The tomographic inversion based on these five spectra is in excellent agreement with numerical simulations with the ASCOT-RFOF and the SPOT-RFOF codes. The length of the measured fast-ion tail corroborates the prediction that very few particles are accelerated above 2 MeV due to the weak wave-particle interaction at higher energies

New Nanostructured Carbon Coating Inhibits Bacterial Growth, but Does Not Influence on Animal Cells

An electrospark technology has been developed for obtaining a colloidal solution containing nanosized amorphous carbon. The advantages of the technology are its low cost and high performance. The colloidal solution of nanosized carbon is highly stable. The coatings on its basis are nanostructured. They are characterized by high adhesion and hydrophobicity. It was found that the propagation of microorganisms on nanosized carbon coatings is significantly hindered. At the same time, eukaryotic animal cells grow and develop on nanosized carbon coatings, as well as on the nitinol medical alloy. The use of a colloidal solution as available, cheap and non-toxic nanomaterial for the creation of antibacterial coatings to prevent biofilm formation seems to be very promising for modern medicine, pharmaceutical and food industries

Northern Sea route and climate change

The Arctic Sea Route, also known as the Northern Sea Route, is experiencing profound changes due to the effects of climate change. This transformation is opening up new economic opportunities and geopolitical challenges, all while raising significant environmental concerns. The diminishing sea ice, thinning ice cover, and the development of new routes have reduced shipping distances, making this once largely impassable region increasingly accessible for global commerce. Economic implications include reduced shipping distances, expanded trade opportunities, and the potential for resource extraction, particularly for oil, gas, minerals, and fisheries. Geopolitically, the region is witnessing a complex interplay of cooperation and competition among Arctic states, with implications for international relations and territorial claims. Environmental risks, such as oil spills and habitat disruption, are significant, while infrastructure development and technological advancements are reshaping the logistics of Arctic navigation. The Arctic Sea Route's future hinges on how the international community addresses these multifaceted impacts, striking a balance between economic interests, environmental preservation, and peaceful cooperation in the face of shifting global dynamics and the urgent need to combat climate change

Arctic Ice Changes and Global Warming

The Arctic, a region of ecological and climatic significance, is undergoing unprecedented ice changes due to climate change. This transformation, marked by rapid reductions in sea ice extent, thickness, and the persistence of multi-year ice, has far-reaching consequences for ecosystems, biodiversity, and global climate patterns. This article examines the historical perspective of the Arctic's ice dynamics, revealing a oncestable environment now in the throes of rapid change. The current state of Arctic ice is analyzed, emphasizing alarming reductions observed through satellite imagery and the implications for rising sea levels and disrupted ecosystems. Rooted in the causes of Arctic ice changes, primarily driven by the greenhouse gas effect, the article underscores the urgent need for global mitigation efforts. Scientific research and models provide critical insights, enhancing our understanding of the complex interactions driving these changes. Mitigation and adaptation strategies are discussed as essential components of a holistic approach, emphasizing the interconnectedness of the Arctic's fate with global efforts to address climate change. The exploration of Arctic ice changes serves as a call to action for international collaboration, sustainable practices, and a shared commitment to preserving the delicate balance of our planet's climate