INVESTIGATION OF HULL STRENGTH OF RIVER SEA CONTAINER VESSEL

River sea vessels are ships for inland navigation and suitable for restricted navigation at sea in regions where, - significant wave height does not exceed 2m, according to Bureau Veritas Rules for the classification of inland vessels. In a container vessel structure, almost the entire deck space is occupied by hatches, leaving a narrow strip of deck plating outboard. This calls for a topside structure of heavy plating or a double hull to provide material in tension, stiffness against lateral and torsional loads, and resistance to buckling in compression when the vessel is in sagging condition. For sea going open deck vessels, torsional loading plays a predominant part to the hull girder strength and for inland navigation open deck vessels; the effect of torsion is rather negligible. Keeping this scenario in mind, the aim of this project is to investigate the hull strength of a river sea container vessel under combined bending and torsional loading to study the effect of torsion on river sea open deck vessel. To perform the strength analysis, firstly, a finite element model is created using Femap with NX Nastran software for the investigated vessel. Therefore, still water and wave loads are calculated using direct calculation. To find out the still water loads Argos software is used and for the wave induced loads potential flow software Hydrostar is used. Next, Finite element model is verified with classical beam theory and thin wall girder theory. Then the effect of various loading conditions on structural response is investigated. After, structural response of different hull configurations are scrutinized under combined bending and torsional loading. Finally, some recommendations are proposed for structural response of river sea container vessel subjected to combined bending and torsional loading.

Hypercubes of AGN Tori (HYPERCAT). II. Resolving the Torus with Extremely Large Telescopes

Recent infrared interferometric observations revealed sub-parsec scale dust distributions around active galactic nuclei (AGNs). Using images of Clumpy torus models and NGC 1068 as an example, we demonstrate that the near- and mid-infrared nuclear emission of some nearby AGNs will be resolvable in direct imaging with the next generation of 30 m telescopes, potentially breaking degeneracies from previous studies that used integrated spectral energy distributions of unresolved AGN tori. To that effect we model wavelength-dependent point spread functions from the pupil images of various telescopes: James Webb Space Telescope, Keck, Giant Magellan Telescope, Thirty Meter Telescope, and Extremely Large Telescope. We take into account detector pixel scales and noise, and apply deconvolution techniques for image recovery. We also model 2D maps of the 10 μm silicate feature strength, S 10, of NGC 1068 and compare with observations. When the torus is resolved, we find S 10 variations across the image. However, to reproduce the S 10 measurements of an unresolved torus a dusty screen of A V > 9 mag is required. We also fit the first resolved image of the K-band emission in NGC 1068 recently published by the GRAVITY Collaboration, deriving likely model parameters of the underlying dust distribution. We find that both (1) an elongated structure suggestive of a highly inclined emission ring, and (2) a geometrically thin but optically thick flared disk where the emission arises from a narrow strip of hot cloud surface layers on the far inner side of the torus funnel, can explain the observations.

Free vibrations of a thin-walled curvilinear section of an oil-trunk pipeline during ground laying

In this article authors obtained solutions to determine the ground curved sections free vibrations of thin-walled large-diameter pipelines with a liquid flow, based on a geometrically nonlinear version of the semi-momentless toroidal shells medium bending theory by V.Z. Vlasov and V.V. Novozhilov. The pipeline is a toroidal shell, the design scheme is presented in the form of a half torus. Angle β = 1800. The shell is laid on an elastic foundation and makes contact with the ground along a narrow strip. The problem of the soil pressure influence on the shell along a narrow strip is solved as a contact problem, using Fourier's series and an impulse function. The shell is exposed to the cooperative effect of the internal operating pressure, the liquid flowing pressure, the elastic soil foundation, and changes in the geometric characteristics. Motion equations of the middle shell surface are obtained taking into account the geometric and mechanical characteristics, and all the components of the shell material inertial forces. The hinged fastening of the shell ends is taken as the limiting condition. Using the semi-momentless shell theory assumptions, displacements in the longitudinal and circumferential directions are obtained. The solution to the problem of determining the free vibrations comes down to solving the problem of determining AB matrix values. The solutions obtained make it possible to determine the free vibrations frequencies at various wavenumbers values in the longitudinal and circumferential directions, and also make it possible to determine the internal operating pressure contribution, the soil bed coefficient, and geometric characteristics to the pipeline free vibrations frequencies.

Echinoderm research perspectives: A Central American bibliometric review

Introduction: Central America, a narrow strip of land dividing the Atlantic and Pacific oceans, has a high diversity of marine and terrestrial species. Echinoderms are one of the most diverse marine groups with 420 reported species. Objective: To summarize echinoderm research in Central America. Methods: We compiled the literature from SCOPUS, Web of Science, SciELO, Google Scholar, Biodiversity Heritage Library, the Internet Archive and the Smithsonian Library. Results: We found 324 publications dating from 1840 to 2020; the early studies had a strong taxonomic focus, but after the 1970s, ecology, evolution and reproduction gained prominence. Echinoidea is the most studied class (38% of publications) due to its use in evolutionary studies as well as the importance of the genus Diadema in reef ecology and dynamics. Conclusion: We recommend more research on fisheries management, conservation and environmental education; and greater integration of local and international research.

DESERT AND SEMI-DESERT VEGETATİON OF GARAGUSH MOUNTAIN

Desert and semi-desert vegetation It is observed in the form of a narrow strip from north to south, and local spots in the direction of Ordubad region after the Araz Lake. It covers the areas of 600-1000 meters in the plains of Sadarak, Sharur, Boyukduz, Nakhchivan, Gulustan, Yayji, Desta and Ordubad. Some of the typical desert elements have been found in the foothills of Mountain Garagush, especially in the Gendara zone. Of these species, Amaranthaceae Juss. , (Chenopodiaceae Vent.) Suaeda dendroides Mog, belonging to the genus Chenopodiaceae. - Woody herb, Halocnemum strobilaceum (Pall.) Bieb. - Condensed sorrel and Seidlitzia florida (Bieb.) Bunge are examples of flowering marigold species. However, it is possible to claim that the desert vegetation was not fully formed, but that the desert vegetation formed a transition to semi-desert vegetation. Demiler, Gendera, Sariagil, Ramlar and Lizbird valleys of Garagush Mountain have local salinity, ephemeral-gallant (colored soil), gamma (gypsum soil) and sandy areas. The latter sandy area is more noticeable in the Lisbird Valley.

New Zero-Density Results for Automorphic L-Functions of GL(n)

Let L(s,π) be an automorphic L-function of GL(n), where π is an automorphic representation of group GL(n) over rational number field Q. In this paper, we study the zero-density estimates for L(s,π). Define Nπ(σ,T1,T2) = ♯ {ρ = β + iγ: L(ρ,π) = 0, σ<β<1, T1≤γ≤T2}, where 0≤σ<1 and T1<T2. We first establish an upper bound for Nπ(σ,T,2T) when σ is close to 1. Then we restrict the imaginary part γ into a narrow strip [T,T+Tα] with 0<α≤1 and prove some new zero-density results on Nπ(σ,T,T+Tα) under specific conditions, which improves previous results when σ near 34 and 1, respectively. The proofs rely on the zero detecting method and the Halász-Montgomery method.

Fine structure of spatial diode photoresponse profiles measured while scanning a narrow strip-shaped illumination spot with FPA diode

The three-dimensional Monte Carlo simulation of charge-carrier diffusion in a mercury-cadmium-tellurium based focal plane array (FPA) was used to calculate the spatial diode photoresponse profiles measured while scanning a narrow strip-shaped illumination spot with a selected FPA diode in the limit of largest and lowest diode photocurrents. The simulation was performed for a standard 2D n-on-p FPA with square photodiodes. Fine features in measured spot-scan profiles due to the presence of FPA structure were identified, and the de-pendence of these features on the boundary conditions for diffusing charge carriers at the n-type diode regions was demonstrated. An explanation to the shape of the profiles, fully con-sistent with the computational procedure of the problem, is given.

Interplay of seismic and a-seismic deformation during the 2020 sequence of Atacama, Chile.

An earthquake sequence occurred in the Atacama region of Chile throughout September 2020. The sequence initiated by a mainshock of magnitude Mw6.9, followed 17 hours later by a Mw6.4 aftershock. The sequence lasted several weeks, during which more than a thousand events larger than Ml 1 occurred, including several larger earthquakes of magnitudes between 5.5 and 6.4. Using a dense network that includes broad-band, strong motion and GPS sites, we study in details the seismic sources of the mainshock and its largest aftershock, the afterslip they generate and their aftershock, shedding light of the spatial temporal evolution of seismic and aseismic slip during the sequence. Dynamic inversions show that the two largest earthquakes are located on the subduction interface and have a stress drop and rupture times which are characteristics of subduction earthquakes. The mainshock and the aftershocks, localised in a 3D velocity model, occur in a narrow region of interseismic coupling (ranging 40%-80%), i.e. between two large highly coupled areas, North and South of the sequence, both ruptured by the great Mw~8.5 1922 megathrust earthquake. High rate GPS data (1 Hz) allow to determine instantaneous coseismic displacements and to infer coseismic slip models, not contaminated by early afterslip. We find that the total slip over 24 hours inferred from precise daily solutions is larger than the sum of the two instantaneous coseismic slip models. Differencing the two models indicates that rapid aseismic slip developed up-dip the mainshock rupture area and down-dip of the largest aftershock. During the 17 hours separating the two earthquakes, micro-seismicity migrated from the mainshock rupture area up-dip towards the epicenter of the Mw6.4 aftershocks and continued to propagate upwards at ~0.7 km/day. The bulk of the afterslip is located up-dip the mainshock and down-dip the largest aftershock, and is accompanied with the migration of seismicity, from the mainshock rupture to the aftershock area, suggesting that this aseismic slip triggered the Mw6.4 aftershock. Unusually large post-seismic slip, equivalent to Mw6.8 developed during three weeks to the North, in low coupling areas located both up-dip and downdip the narrow strip of higher coupling, and possibly connecting to the area of the deep Slow Sleep Event detected in the Copiapo area in 2014. The sequence highlights how seismic and aseismic slip interacted and witness short scale lateral variations of friction properties at the megathrust.

To the Question about the Functions of Rural Settlements in the Economic System of the Golden Horde

The study posed a question – nomadic steppe or rural settlements provided the cities of the Golden Horde with meat food. In the meat consumption of all the studied cities, the most important place was occupied by beef – the products of mainly rural settlements, lamb and horse meat – the products of steppe cattle breeding, played an auxiliary role. In the cities around which there were unlimited areas for grazing cattle, the proportion of beef in the diet was significantly, 10–20% higher than in steppe and semi-desert cities along the lower reaches of the Volga and Akhtuba, where a narrow strip of azonal landscapes significantly limited grazing. In cities that functioned in the 13th and 14th centuries, the proportion of beef increased significantly in the 14th century. This is due to the formation of rural districts by the 14th century and the establishment of regular supplies of the main meat product from them. The study of archaeozoological collections from five rural settlements of the Volga region and the Crimea revealed a high – 80–85%, the proportion of beef in their meat diet. This means a very high number of cattle kept in rural settlements in relation to other types of domestic ungulates. The villagers of the Golden Horde were engaged in specialized cattle breeding and were the main suppliers of meat products to the Golden Horde cities. In addition, they were important participants in the export of animal skins in the economic system of the state.