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The formation and evolution of tidal jet vortices over complex bathymetry were investigated using numerical modeling and in situ observation. Delft3D FM simulation on an unstructured grid system, complemented by field measurements using recreational drones captured tidal dynamics in the Uldolmok Strait, known for its strong tidal currents up to 6.0 m/s and turbulent whirlpool formation. This study particularly focused on temporal changes in whirlpools near their narrowest points. Modeling across the entire strait showed current velocity fields consistent with field observations, revealing significant temporal and spatial variability influenced by strait geometry and bathymetry. Whirlpools induced by tides were identified by setting a swirl strength threshold, with their centroids and equivalent spherical diameters pinpointed. It was observed that larger whirlpools, upon reaching critical size, were entrained and shifted with the tidal jet at about half its maximum velocity, while smaller vortices separated from the nearshore boundary layer remained nearly stationary. Focusing on the initiation of whirlpools and their relations with the coastline and bathymetry, a targeted field survey using a recreational drone measured surface flow fields in detail near the strait's narrowing region. During the ebb phase, shallow regions exhibited numerous smaller eddies due to increased energy dissipation, showing a dual power‐law scaling in the size distribution of eddies, contrasting with the single scaling exponent observed during the flood phase. The study underscored the role of coastline and bathymetry in developing whirlpools and shaping their dynamics, providing insights into complex tidal interactions in the natural coast. Plain Language Summary: This study employed Delft3D FM computer simulations and drone‐based field measurements to investigate the formation and evolution of swirling water movements (whirlpools) over complex bathymetry in the Uldolmok Strait, known for its powerful tides reaching up to 6.0 m/s. The computer model accurately regenerated the actual seawater motions observed in the strait, showing that the speed and direction of the water varied a lot based on the shape and depth of the strait. The study identified special swirling patterns called tide‐induced whirlpools by looking at how strong the swirls were and where their center points were located. Some larger whirlpools moved along with the tide, but slower than the fastest tide speed. On the other hand, smaller swirling patterns stayed in one place near the shore. To learn more about how these whirlpools start and their relationship with the coastline and underwater features, we used a drone to take detailed measurements of the water's surface and its movement near the narrowest part of the strait. During the ebb phase, shallow areas were found to have a lot more small eddies because of higher energy loss. This leads to different eddy size distributions during the ebb and flood phases. Key Points: Using numerical modeling and in situ measurements, we analyzed tidal currents and whirlpools to understand small‐scale vortical structuresAnalysis of whirlpools shows that tidal jet vortices' evolution, sizes, and shifts depend on tidal dynamics and strait topographyDrone observations reveal distinct power‐law patterns in whirlpool size distributions during ebb and flood phases, influenced by topography [ABSTRACT FROM AUTHOR]

Modified Korteweg-de Vries equations are used to describe certain phenomena in nonlinear optics, fluid dynamics, plasma physics, ocean physics and gas dynamics. In this paper, we investigate a damped variable-coefficient fifth-order modified Korteweg-de Vries equation for the small-amplitude surface waves in a strait or large channel of slowly-varying depth, width and non-vanishing vorticity. Via the truncated Painlevé expansion, Painlevé-type auto-Bäcklund transformations are obtained. Based on the Painlevé-type auto-Bäcklund transformations, periodic solutions and one-soliton solutions are derived. The soliton-like solutions are constructed via the modified Kudryashov method. We graphically show the kink-type solitons of the soliton solutions. Graphic analysis shows that the shapes, characteristic lines and velocities of the solitons are related to α 1 (t) and β (t) , while the soliton backgrounds and amplitudes just depend on γ (t) , in which α 1 (t) , β (t) and γ (t) are the dispersive, dissipative and line-damping coefficients of the equation we investigated, respectively, where t is the temporal variable. [ABSTRACT FROM AUTHOR]

AbstractAmid United States-led efforts to internationalize and multilateralize support for Taiwan and cross-Strait deterrence in response to mounting coercive pressure from China, the April 2021 and May 2021 U.S.-Japan and U.S.-South Korea summit statements’ unprecedented references to ‘peace and stability across the Taiwan Strait’ triggered global headlines. In the 3 years since, U.S. expectations for treaty allies to do and say more in support of Taiwan and cross-Strait deterrence have surged. But what of the perspectives and policies of key front-line treaty allies Japan and Korea, each host to tens of thousands of forward-­deployed U.S. forces? This study comparatively analyzes the historical and contemporary evolution of Japanese and Korean positions and policies vis-à-vis Taiwan and the role their leaders see for their country and respective alliance with the U.S. in the event of a ‘regional contingency’: a conflict not involving—at least initially—armed attacks on ally-administered territory. After highlighting the similarities between Seoul’s and Tokyo’s intentionally ambiguous positions on Taiwan’s status, it explores important differences in each allies’ willingness to deepen practical engagement with Taiwan, to expand their respective alliance’s focus beyond territorial defense, and to stretch the bounds of the ally’s own potential contributions in a regional contingency. [ABSTRACT FROM AUTHOR]

In the present work, the effects of wind- and tide-induced internal waves in the Rio-Antirio Strait in western Greece were studied by using three-dimensional numerical simulations. For the wind-induced flow in the strait, it emerged that the internal waves' initiation is associated with the direction of the wind. Tidal action, with or without the combined action of wind, also generates internal waves in the strait, with amplitudes higher than 20 m. The action of the internal waves causes a subsurface inflow of colder waters from the Gulf of Corinth to the Gulf of Patras, as has been also simulated for the case of the wind-induced flow, generating strong hypolimnetic currents. The exchange flowrate between the Gulf of Patras and the Gulf of Corinth appeared to undergo significant modification for the wind-induced flow and had little effect for the pure tidal flow (in windless conditions) due to the development and action of the internal waves at the strait. The combined action of the tide and the wind was found to marginally affect the exchange flowrate between the two gulfs compared to the pure tidal flow. The interaction between the Coriolis effect and internal waves, at least away from the strait, forms a characteristic horizontal structure of flow. The structure of turbulence in the near strait area under the action of internal waves generated by the wind and/or tide was also discussed and compared with the corresponding barotropic flow. [ABSTRACT FROM AUTHOR]

Thin, condensed coarse-grained shallow marine successions can be difficult to describe and interpret, especially in the subsurface since the recognition of finer-grained intervals, typically associated with sequence stratigraphic surfaces, is challenging. This lack of mudstones and siltstones means that they also typically make excellent reservoir intervals. The Oxfordian to Volgian intra-Draupne Formation sandstones in the Johan Sverdrup Field, southern Utsira High, represent such a system. This study presents a new sequence stratigraphic model for the Johan Sverdrup Field that unravels the detailed depositional history of the succession and places its formation within a regional Late Jurassic tectonostratigraphic framework. The intra-Draupne Formation sandstones comprise four parasequences deposited following a regional Kimmeridgian marine flooding event. Sediments were mainly supplied through West-derived fan deltas from the Haugaland High and NW-SE-directed tidal currents reworking the Augvald Graben and the Avaldsnes High at the East. The oldest parasequence shows a distinctive suite of facies consisting of fine-grained and mud-rich bioturbated sandstones deposited in a semi-restricted lagoon. Subsequent parasequences lack fine-grained sediments and are dominated by bidirectional cross-stratified, very coarse-to coarse-grained sandstones and gravels deposited in a tidal strait. A progressive reduction of fault-related subsidence in the Middle Volgian along with Late Volgian-Ryazanian sea-level rise and inversion of pre-existing structures promoted backstepping of the feeder systems, sediment starvation and the progressive deposition of the black and green-red shales of the Draupne and Asgard formations. The results of this study account for features previously unidentified in the Johan Sverdrup Field and which have implications for understanding the deposition of coarse-grained shallow marine successions around the Utsira High and other transgressed basement highs. [ABSTRACT FROM AUTHOR]

In compliance with the progress of the Belt and Road (B&R) initiative, there exists a notable and continuous increase in the reliance on maritime and onshore transportation. Therefore, unimpeded transportation has become China's goal to ensure its security of trade and energy resources. This study proposes a useful framework for the quantitative assessment of key Strategic Transport Passages (STPs) to identify and rank China's STPs in the context of the B&R. An evaluation hierarchy consisting of general criteria and sub-criteria is developed to evaluate the strategic value of alternative passages. The Evidential Reasoning method is employed to carry out the synthesis process with the Intelligent Decision System software package as it is effective when combining both qualitative and quantitative criteria of a complex nature. Finally, China's top ten STPs and their ranking are determined by their associated strategic values. The Strait of Hormuz ranks first followed by the Strait of Malacca. Alashankou, located in the Xinjiang Uyghur Autonomous Region, China, is the only onshore passage among the top ten STPs. Though the Panama Canal is not involved with the B&R, it is still within the top ten STPs, due to its economic significance. [ABSTRACT FROM AUTHOR]

In the present work, the effects of wind- and tide-induced internal waves in the Rio-Antirio Strait in western Greece were studied by using three-dimensional numerical simulations. For the wind-induced flow in the strait, it emerged that the internal waves’ initiation is associated with the direction of the wind. Tidal action, with or without the combined action of wind, also generates internal waves in the strait, with amplitudes higher than 20 m. The action of the internal waves causes a subsurface inflow of colder waters from the Gulf of Corinth to the Gulf of Patras, as has been also simulated for the case of the wind-induced flow, generating strong hypolimnetic currents. The exchange flowrate between the Gulf of Patras and the Gulf of Corinth appeared to undergo significant modification for the wind-induced flow and had little effect for the pure tidal flow (in windless conditions) due to the development and action of the internal waves at the strait. The combined action of the tide and the wind was found to marginally affect the exchange flowrate between the two gulfs compared to the pure tidal flow. The interaction between the Coriolis effect and internal waves, at least away from the strait, forms a characteristic horizontal structure of flow. The structure of turbulence in the near strait area under the action of internal waves generated by the wind and/or tide was also discussed and compared with the corresponding barotropic flow.

The Strait of Belle Isle (SBI) is an important pathway for water mass exchanges between the Labrador Shelf and the Gulf of St. Lawrence (GSL), particularly for transport toward the GSL. Seasonal and inter‐annual variability of transport in the SBI are examined using 15 years of moored acoustic Doppler current profiler data. Tidal currents are largely along strait and homogeneous with depth. Transports are toward the GSL on average, lowest (−1.0 ± 0.8 dSv) from April to July, and highest (−4.0 ± 1.1 dSv) from September to January. Averaged seasonal transports are usually within one standard deviation of previously published modeled values. The volume of winter Labrador Shelf water (LShW) entering the GSL is computed by transport integration and compares well with integrated volumes that meet LShW temperature‐salinity criteria during an annual March survey of the GSL. Integrating over the whole year showed that on average 649 ± 397 km3 enters the GSL after the March surveys are conducted, independently of the volume that has entered up to March; this addition represents on average about a third of the total volume. Annual volumes of LShW calculated from transport suggest that flow through the SBI accounts for 12%–18% of the GSL winter surface mixed layer. Cross‐strait current shear may affect transport integration values, but sea surface temperature data suggests this bias is limited to the summer. Corrections are empirically derived to account for cross‐strait shear in our transport calculation. The corrected time series suggests that the average transport may be flowing toward the Labrador Shelf in July (0.6 ± 1.0 CI [0.1 1.1] dSv). Plain Language Summary: The Strait of Belle Isle (SBI) is the waterway at the northeastern end of the Gulf of St. Lawrence (GSL) that connects it to the Labrador Shelf, and where water may move in both directions. Despite its importance, there are not many recent measurements of water movement across this strait. This is because the SBI is remote from most routine oceanographic operations, and strong currents, sea ice, and icebergs complicate mooring design and restrict study site selection. Our study presents 15 years of new measurements obtained using contemporary technologies allowing for a better assessment of the contribution of Labrador Shelf waters to the GSL. In the future, they may also contribute to improving ocean models of the Northwest Atlantic. Key Points: A 15‐year Strait of Belle Isle transport time series is calculated from mooring‐based acoustic Doppler current profiler dataTransport is used to estimate Labrador Shelf Water contribution to the Gulf of St. Lawrence winter cold layerCorrecting for cross‐strait shear suggests that dominant July transport is toward the Labrador Shelf [ABSTRACT FROM AUTHOR]

The continued warming of the Arctic atmosphere and ocean has led to a record retreat of sea ice in the last decades. This retreat has increased the probability of the opening of the Arctic Passages in the near future. The Northwest Passage (NWP) is the most direct shipping route between the Atlantic and Pacific Oceans, producing notable economic benefits. Decadal variations of sea ice and its influencing factors from a high-resolution unstructured-grid finite-volume community ocean model were investigated along the NWP in 1988–2016, and the accessibility of the NWP was assessed under shared socioeconomic pathways (SSP245 and 585) and two vessel classes with the Arctic transportation accessibility model in 2021–2050. Sea ice thickness has decreased with increasing seawater temperature and salinity, especially within the Canadian Arctic Archipelago (CAA) in 1988–2016, which has facilitated the opening of the NWP. Complete ship navigation is projected to be possible for polar class 6 ships in August–December in 2021–2025, after when it may extends to July under SSP585 in 2026–2030, while open water ships will not be able to pass through the NWP until September in mid-21st century. The navigability of the NWP is mainly affected by the ice within the CAA. For the accessibility of the Parry Channel, the west part is worse than that of the eastern part, especially in the Viscount-Melville Sound.

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Three major and very different controversies oppose the countries of the Arctic. First, there is the question of the status of the potential maritime routes of the Northwest and Northeast Passages, while scenarios predict an increase in navigation. Next, there is the question of the extension of economic sovereignty over the continental shelves, beyond the 200 nautical mile line, and the border disputes that overlap could give rise to. Finally, fueled by the concern of the Arctic States to assert their control over the maritime areas that are freeing from the ice, security policies sometimes appear as a militarization of the Arctic, in particular for Russia and, for a time, for Canada. These three controversies differ as much in stakes as in the fact of changing alliance games. But do these phenomena really reflect a surge in geopolitical issues for the Arctic ?

The dynamics of phytoplankton biomass in the vertically mixed south-eastern part of the Bisan Strait, in the Seto Inland Sea of Japan, may be considered to be strongly dependent not only on nutrients but also on light status. This was investigated by examining variations in chlorophyll-a (Chl-a), nutrients, and Secchi-disc depth through high-frequency sampling (a mean of once every 1.7 days) at the same station from April to October 2019. Precipitation during the Japanese rainy season (East Asian monsoon rains) was associated with a decrease in salinity from 32 to 31 in late July. The highest concentration of dissolved inorganic nitrogen (DIN), the most deficient nutrient, also was recorded in late July in association with seasonal precipitation. However, the measured Chl-a peak (max. 4 μg l−1) in early August was not as high as expected, possibly due to low water clarity. A relatively small but substantial peak of DIN (max. 4 μM) was recorded in mid-August, which coincided with the passing of a typhoon. The small peak of DIN coupled with higher water clarity thereafter was followed by a phytoplankton bloom from mid-August to early September, at which the highest Chl-a (7 μg l−1) occurred. It is suggested that increased light penetration enhanced the efficiency of nutrient assimilation and thereby triggered the late-summer phytoplankton bloom. In contrast to the adjacent stratified areas, light rather than nutrient status appears to be the key determinant for the onset of phytoplankton blooms in the Bisan Strait. [ABSTRACT FROM AUTHOR]

This essay examines complex interactions among the nation-state, popular religion, media capitalism, and gendered territorialization as these are inflected across the Taiwan Strait. Relations across the strait have been fraught with political tension and military preparations over the question of whether taiwan is part of China or an independent state. Since the 1999 presidential elections in Taiwan, the new government there has been more vociferous about Taiwan independence, and mainland China's Communist Party has responded with more vigorous claims on Taiwan, including the launching of a warning missile over the island. Under these conditions, it is all the more remarkable that in recent years there has been an increasing number of religious pilgrimages and exchanges across the strait, and that, in 2000, one such pilgrimage by Taiwanese worshippers of the maritime goddess Mazu to her natal home in Fujian Province was broadcast live from China back to Taiwan via satellite television.

Straits and canals have always served as key nodes in shipping networks. The blockage of a strait or canal will lead to ship deviations and increased transportation costs. To measure this impact on the Chinese fleet, our study develops a mathematical model that is based on a programming formulation. Each strait or canal is assumed to be blocked in turn, and the increased transportation costs for the Chinese fleet in different scenarios are calculated and compared using the proposed programming formulation in order to measure the impact of the blocked strait or canal on the Chinese fleet. Larger increases in transportation costs have greater impacts on the fleet. The results show that a blockage of the Strait of Hormuz would have the greatest impact of all straits and canals; it would cause the Chinese fleet to lose a portion of its import and export market, and such a blockage cannot be addressed through ship deviations. Based upon increased transportation costs, the four straits or canals that would have the greatest impact if blocked are the Mandeb Strait, the Suez Canal, the Sunda Strait and the English Channel. [ABSTRACT FROM AUTHOR]

In the 16th–17th centuries, West European navigators made numerous but mostly unsuccessful efforts to open a new way, i.e. the North-East Passage, to China and India. Among three possible routes of that time the basic one ran through straits of the Vaigach Island but it was almost impassable due to heavy ice situation. At the same time Russian merchants regularly went on their ships from Pomorie to Siberian river mouths, and in the opposite direction, though they did also meet complicated ice situations. Russian navigator and geographer F.P. Litke (1797–1882) noticed that the ice situation in one or another region of the Barents Sea seriously changed from year to year. Russian navigation started in the Russian Pomorie (littoral region of the Russian Arctic) not earlier than at end of June – beginning of July but Europeans knew nothing about this. Because of this, their ships came to the Vaigach region either earlier or later of the time when it was possible to go through the straits. Most often, they came here in the first half- and mid-August. Thus, western sailors could not get this quite narrow navigation «window» of pomors (Russian navigators). And if sometimes (rather rarely) they could catch the right time and go through the strait Yugorski Shar they met extremely heavy ice situation in the Kara Sea. Perhaps for this reason, almost all European expeditions of that time failed.

The annual current energy potential of a sea strait, Bosphorus in Turkey, is evaluated by the calibrated and validated three dimensional numerical model results. The numerical approach is based on a number of unstructured flexible meshes (triangle or quadrilateral elements) and uses a cell-centered finite volume solution technique. Three-dimensional incompressible Reynolds averaged Navier-Stokes equations are solved invoking the assumptions of Boussinesq and hydrostatic pressure. The turbulence closure was implemented by using Smagorinsky and k- ε models in the horizontal and vertical domains, respectively. Water level and density differences acting on the model open boundaries combined with the meteorological structure of the region (wind speed, direction and atmospheric pressure difference) are the main forcing mechanisms of the numerical model as inputs. The strait flow is a typical example of a stratified flow among the world's straits, with a possible exception of having a negligible tidal oscillation. The results show that the complex geometry (both horizontally and vertically) of the strait combined with highly variable hydrological and meteorological conditions of the adjacent seas, the Marmara Sea and Black Sea, result in a considerable fluctuation in the kinetic energy potential. Cross-sectional variability of the kinetic energy is also notable both horizontally and vertically with increasing energy upwards and towards the shore. In spatial domain, although it is not the narrowest part of the strait, the highest kinetic energies are calculated at the southernmost part of the strait due to both a decrease in cross-sectional area and the presence of a sill on the bottom, a geometrical feature likely seen in straits that mainly control the flow structure (e.g., flow velocities). For a given cross section taken from a meandering part of the strait, the kinetic energy of the strait is higher at the outer and inner banks of the strait for the upper and lower layer flows, respectively. In time scale, the most energetic time period spans from the late spring to the end of summer related to the increase in water level difference between both ends of the strait due to long-term effects that represent seasonal variations (mainly the river inflows toward the Black Sea) and short-term effects (southward storms in the same direction with the upper layer flow). In winter, however, due to the southerly storms acting opposite to the surface layer flow, the kinetic energy potential of the strait drops to considerably low values occasionally. [ABSTRACT FROM AUTHOR]

Tidal resource assessment is presented for Rathlin Sound, located between Rathlin Island and the north-east coast of Northern Ireland. The flow is simulated in 2D, using the shallow water equations. For an M 2 tide, the natural flow conditions exhibit local spatial mean and maximum flow speeds of 2 and 3 m/s. Upper limits to power extraction are about 298 MW for M 2 and 330 MW for M 2 +S 2 tidal signals (different to undisturbed kinetic power and power naturally dissipated at the seabed). An analytical model of a channel connecting two infinite ocean basins underpredicts maximum power extracted in Rathlin Sound due to changes in head driving the flow and the existence of an alternative flow path. At maximum power extracted, there is substantial reduction in mean flow speeds in the strait and to the south-east of Rathlin Sound. In the strait, maximum power is reduced by 14% and 36% for blockage ratios of 80% and 60%. Power extraction both offshore of the island and in the strait yields higher power generation rates than isolated extraction. Resource assessments for Rathlin Sound are generally in good agreement with those for an idealised strait between an island and landmass. [ABSTRACT FROM AUTHOR]

Renewable energy technologies are undergoing rapid development, the global aim being to achieve energy security and lower carbon emissions. Of marine renewable energy sources, tidal power has inherent predictability and large theoretical potential, estimated to exceed 8000 (TW h)a −1 in coastal basins. Coastal sites in the vicinity of an island near a landmass are prime candidates for tidal stream power exploitation by arrays of turbines. This paper characterizes numerically the upper limit to power extraction of turbines installed at such sites. It is demonstrated that the maximum power extracted from the strait is generally not well approximated by either the power dissipated naturally at the seabed or the undisturbed kinetic power of flow in the strait. An analytical channel model [C. Garrett and P. Cummins, “The power potential of tidal currents in channels,” Proc. R. Soc. A Math. Phys. Eng. Sci., vol. 461, no. 2060, pp. 2563–2572, Aug. 2005] provides lower predictions than the present numerical model of available power in the strait due to the analytical model not accounting for changes to the driving head resulting from power extraction and flow diversion offshore of the island. For geometrically long islands extending parallel to the landmass, the numerically predicted extracted power is satisfactorily approximated by the power naturally dissipated at the seabed, and there is reasonable agreement with the estimate by the channel analytical model. It is found that the results are sensitive to choice of boundary conditions used for the coastlines, the eddy viscosity, and bed friction. Increased offshore depth and lower blockage both reduce the maximum power extracted from the strait. The results indicate that power extracted from the site can be maximum if extraction is implemented both in the strait and offshore of the island. Presence of the landmass and increasing island dimensions both enhance power extraction. [ABSTRACT FROM AUTHOR]

Strait and genesis of the carpathian valley of the Danube. Hypotheses, problems, witnesses. When entering Romania, the Danube forms a transversal valley among the rocks of the Carpathian Chain. First of all, there is a great geodiversity concerning these rocks traversed. Then, the valley dug by the river takes form of a very spectacular defile, one of most important natural tourist attraction of Romania and the surroundings. From a genetic point of view, the valley of the Iron Gates has always posed problems for researchers. Even today the assumptions about the formation of the valley are shared. We try to explain these theories, to confront them and to see in what measure they can be taken into consideration today to better understand the geomorphological evolution of this region.

Wind, flow and wave measurements were performed in November-December in 2008 in the relatively narrowand shallow Suur Strait connecting the waters of the Väinameri and the Gulf of Riga.During the measurement period wind conditions were extremely variable, including a severe storm on 23 November. The flow speedalong the strait varied between ±0.2 m s-1, except for the 0.4 m s-1 that occurred after the storm as a result of the sealevel gradient. The mean and maximum significant wave heights were 0.53 m and 1.6 m respectively. Because of their longer fetch, southerlywinds generated higher waves in the strait than winds from the north. All wave events caused by the stronger southerly windsinduced sediment resuspension, whereas the current-induced shear velocity slightly exceeded the critical value for resuspensiononly when the current speed was 0.4 m s-1. A triple-nested two-dimensional high resolution (100 m in the Suur Strait) circulation model and the SWANwave model were used to simulate water exchange in 2008 and the wave-induced shear velocity field in the Suur Strait respectively. Circulation model simulations demonstrated that water exchange was highly variable, that cumulative transport followed an evident seasonal cycle, and that there was an grossannual outflow of 23 km3 from the Gulf of Riga. The horizontal distribution of wave-induced shear velocityduring the strong southerly wind event indicated large shear velocities and substantial horizontal variability. The shearvelocities were less than the critical value for resuspension in the deep area of the Suur Strait.

This article considers the problematic issue of the prehistory of the Kaliningrad region. The author analyses different approaches to the periodisation of the East Prussian offensive, delimits the periods of its stages and determines the date of the termination of the operation.

This article considers the problematic issue of the prehistory of the Kaliningrad region. The author analyses different approaches to the periodisation of the East Prussian offensive, delimits the periods of its stages and determines the date of the termination of the operation.

Currently, submerged floating tunnel still stays in scientific research stage, while many submerged tunnels have been built by use of borehole-blasting method, shield method, immersed tube method and other traditional construction methods. This paper, through wide literature research and engineering data collection, analyzes construction environment limits and typical operating diseases of submerged tunnels for various traditional construction methods, and, specific to the eight typical major water areas including Taiwan Strait, Qiongzhou Strait, Bohai Strait, Bering Strait, and Messina Strait, discusses and analyzes enlightenment to floating tunnel project of existing submerged tunnel: (1) For submerged tunnels using traditional construction method, only from the point of view of construction environment limits, existing construction experience and technology have already been not suitable for 50∼87.5% of typical major water areas, technical breakthrough or innovation is required, while floating runnel will be one of the effective options for these water areas. (2) For construction of submerged tunnels in part of major water area, combination of traditional construction method+floating method will be one effective method. (3) Water leakage, lining material degradation and rebar corrosion and expansion and other diseases and specific difficulties in maintainability and durability of structure and connection components for submerged tunnels using traditional construction method will be main operating diseases for floating tunnel. [ABSTRACT FROM AUTHOR]

When entering Romania, the Danube forms a transversal valley among the rocks of the Carpathian Chain. First of all, there is a great geodiversity concerning these rocks traversed. Then, the valley dug by the river takes form of a very spectacular defile, one of most important natural tourist attraction of Romania and the surroundings. From a genetic point of view, the valley of the Iron Gates has always posed problems for researchers. Even today the assumptions about the formation of the valley are shared. We try to explain these theories, to confront them and to see in what measure they can be taken into consideration today to better understand the geomorphological evolution of this region. [ABSTRACT FROM AUTHOR]

From the anarchic Persian hordes of Xerxes to the phlegmatic British battalions of Churchill, the attempt to crossing the Dardanelles has resulted not only challenging but costly and deadly. Paradoxically, the only harmless to jump from Europe to Asia was Alexander the Great to begin the victorious conquest of the Achaemenid Empire. [ABSTRACT FROM AUTHOR]

This paper focuses on continuing impacts of 'old' empires and newer geopolitical players on unfolding histories in the Gibraltar region, especially narratives related to the British Overseas Territory of Gibraltar (BOT), and Spain's presence in Ceuta and Melilla in Morocco. Tensions remain between state-centric and evolving people-centric interpretations of international law and decolonization; populations in the respective territories do not wish 'decolonization' of 'their' territories by the states that control them, but rather greater self-determination and democratic relationships with the international community. [ABSTRACT FROM AUTHOR]

The Dover strait is knowwell for its High trafic density. In this context, it is seem as a major strategic Gateway, a node of international flows. On the scale of the territory, Dover strait is a maritime way, where two shores face each other : the Kent Council and the Pas-de-Calais Department, linked by maritime links and a tunnel, which should remind the remaining border between the two shores. However, a recent approach concerns initiatives for increased local communities, a memorandum of understanding, which is an important step for the joint and coordinated management of the strait. The latest actions carried out are initiative indicators of local authorities governance in the strait. The future assessment of NOSTRA project will probably confirm the need of a local management in an international shipping area.

The Strait of Gibraltar is a singular place in which numerous lines, thresholds, and demarcations superimpose and intersect. This strait marks also the border of three States and it represents one of the significant points of entry in Schengen space. Thus it articulates and separates political entities and it establishes a junction between distinct human, social, and religious universes. In this context its analysis appears therefore a heuristic example for border studies. The wealth and the diversity of this border which is at the same time a crossroad and a limit at different scales, involve to develop a reading grid of “in-betweenness” or interface. The modelling of borders and their evolution starting from the concept of in-betweenness are then discussed.