Ringed Seals Research Articles

Seasonal distribution of ringed seal in the White Sea monitored by satellite tagging

Data on the seasonal distribution and ecology of ringed seals (Pusa hispida) were obtained from the results of seal tagging with satellite telemetry transmitters (STT) in the White Sea. STT "Pulsar" worked in the Argos system. Catching and tagging of ringed seals were carried out in the Dvina Bay of the White Sea in autumn 2008 and 2016 and in the summer of 2020. 5 tags were installed on seals of different ages. It was shown in the summer the ringed seals did not make long movements and remained on the littoral. The seals moved long distances in autumn, the average daily distance between observation points was 43 km per day. The ringed seal preferred areas with open water and the sea edge of landfast ice in winter. The ringed seal could stay for more than two months in the pelagic zone above the depth of 20 m. Priority directions of movement haven’t been identified. We suggest this feature of the seals' behavior in the White Sea is associated with the seasonal distribution of food.

Size effect on the cyclic deformation behavior of superalloy ultrathin sheet: Characterization and multiscale modelling

Superalloy ultrathin sheets have high strength, outstanding oxidation resistance, corrosion resistance and fatigue performance, and its thin-walled components occupy a considerable proportion in aeroengines. In the microforming process of aeroengine thin-walled components, the superalloy ultrathin sheet is often deformed under complex loading states and shows obvious springback. However, the forming and springback laws of superalloy ultrathin sheet in the microforming process are not clear and often affected by size effect. In addition, the existing nonlinear kinematic hardening models cannot accurately forecast the deformation and springback of superalloy ultrathin sheets. To address this issue, the cyclic shearing tests were performed to systemically explore the size effect on Bauschinger effect, permanent softening, transient hardening and work hardening stagnation of superalloy ultrathin sheets under cyclic loading states. The mechanism of size effect on cyclic mechanical response was systematically revealed through microstructure evolution combined with surface layer effect. In addition, a new multiscale cyclic hardening model was proposed based on the Y-U model and size effect on cyclic deformation behavior of superalloy ultrathin sheets. The new multiscale cyclic hardening model coupling surface layer effect and grain boundary strengthening effect was constructed by modeling the relationship between the cyclic mechanical response and size effect. Comparisons between the original Y-U model and the new proposed model on the characterization effect of shear stress-strain curves demonstrated that the proposed cyclic hardening model can accurately present the cyclic deformation behavior. To further verify the prediction capability of the proposed cyclic hardening model, the springback behavior of superalloy ultrathin sheet in U-bending test and hydroforming of seal ring was predicted via the proposed model combined with the decrease of elastic modulus and Yld2000–2d yield criterion, and the predicted results were compared with experimental ones. Comparative research revealed that the proposed cyclic hardening model can accurately describe the cyclic deformation behavior and springback of superalloy ultrathin sheets affected by size effect.

The performance of double-layer rubber sealing ring under the action of low temperature environment

Aiming at the sealing failure of a water quality monitoring system in a low-temperature environment, a double rubber O-ring sealing structure was designed, and its sealing performance at low temperatures was studied. Finite element software ANSYS constructed the sealing structure, and the change of sealing performance of rubber O-ring in the process of standard temperature installation and low temperature was studied by a two-dimensional axisymmetric model. The results show that the equivalent strain and stress of the sealing structure show an increasing trend during the installation process. With the effect of the medium pressure, the maximum contact stress of the rubber seal ring increases from 2.6285 MPa at 20 ℃ to 2.6657 MPa at 0 ℃. The contact width decreases gradually with the decrease in temperature. With the initial compression rate increase, the maximum contact stress increases significantly. The simulation results show that the double-layer rubber O-ring structure still has good sealing performance at low temperatures.

Analysis of Sealing Performance of Cone Reamer

When the cone reamer is working, the upper end face of the piston contacts the drilling fluid. The sealing structure is used to isolate the drilling fluid at the upper and lower end faces of the piston, thus ensuring the differential pressure between the upper and lower end faces, so as to realize the axial downward movement of the piston. The sealing between the piston and the body will have a direct impact on the expansion quality of the reamer, and affect the subsequent reaming quality. At the same time, the seal ring may be squeezed into the gap between the body and the piston during the dynamic sealing process, resulting in. Therefore, this section carries out simulation analysis on the sealing structure, discusses its sealing performance and optimizes the structure.

No accumulation of microplastics detected in western Canadian ringed seals (Pusa hispida)

Ringed seals (Pusa hispida) play a crucial role in Arctic food webs as important pelagic predators and represent an essential component of Inuvialuit culture and food security. Plastic pollution is recognized as a global threat of concern, and Arctic regions may act as sinks for anthropogenic debris. To date, mixed evidence exists concerning the propensity for Canadian Arctic marine mammals to ingest and retain plastic. Our study builds on existing literature by offering the first assessment of plastic ingestion in ringed seals harvested in the western Canadian Arctic. We detected no evidence of microplastic (particles ≥80 μm) retention in the stomachs of ten ringed seals from the Inuvialuit Settlement Region (ISR) in the Northwest Territories, Canada. These results are consistent with previous studies that have found that some marine mammals do not accumulate microplastics in evaluated regions.

Design of three-stage sealing structure and investigation of sealing performance for 7000 fracturing plunger pump

As a key component of the drilling mud pump, the plunger seal often has problems such as seal failure in reconstruction of low-permeability sandstone reservoirs and the development of unconventional reservoirs, which, in turn, leads to low efficiency of drilling mud pumps and even great potential safety hazard. Based on this, this paper designs a three-stage sealing device at the hydraulic head for the 7000 fracturing plunger pump, and analyzes the sealing performance of the system. The effects of different working loads of the hydraulic head and axial pre-tightening force on the contact force of the seal ring and the stress distribution in the seal ring are explored, and the sealing effect of the three-stage seal of the fracturing plunger pump is confirmed. The results show that the peak stress and the peak contact pressure of the three rubber rings increases with the increasing of the working load of the hydraulic head; the peak stress and the peak contact stress of the three rubber rings during the installation process increase with the increase of the installation pre-tightening force. But the equivalent stress peak and the contact stress peak are directly related the fluid load under the action of the working fluid load; the maximum contact force of the rubber during the sealing process of the system is greater than that of the system working medium under different working fluid pressures. With internal pressure, the three sealing rubber rings can play a sealing role to varying degrees in sequence, and increasing the total life of the sealing body.

CFD study of transient heating and cooling of a blank mould with a conformal cooling channel for manufacturing glass containers

Narrow Neck Press and Blow is a glass moulding process that produces a lightweight container by pressing the glass in the blank mould, baffle, and neck ring to form a parison. This paper presents a cyclic transient computational fluid dynamics study to evaluate the thermal performance of a novel blank mould (ShellMould) for the glass industry. ShellMould consists of two cast iron parts, an outer shell and a moulding core, and a conformal cooling channel between these parts. Fins placed strategically inside the conformal channel promote heat transfer between the cooling airflow and the blank. A mould with straight cooling channels currently used by the glass industry was considered as the reference case model. The mould thermal performance was assessed based on three parameters: an Index of Temperature Heterogeneity, the heat removal rate, and the average temperature in the moulding surface at the blank, baffle seal, and neck ring. It is shown that ShellMould can reduce the operating temperature by 100 °C and improve the heat removal rate by 190 up to 202 [W]. Results reveal the main challenges for improving the ShellMould cooling and temperature homogeneity, mainly in the neck ring, where the cooling efficiency dropped by 10%.

Genomic evidence uncovers inbreeding and supports translocations in rescuing the genetic diversity of a landlocked seal population

Fragmentation of isolated populations increases the risk of inbreeding and loss of genetic diversity. The endemic Saimaa ringed seal (Pusa hispida saimensis) is one of the most endangered pinnipeds in the world with a population of only ~ 400 individuals. The current genetic diversity of this subspecies, isolated in Lake Saimaa in Finland for ca. 1000 generations, is alarmingly low. We performed whole-genome sequencing on Saimaa ringed seals (N = 30) and analyzed the level of homozygosity and genetic composition across the individual genomes. Our results show that the Saimaa ringed seal population has a high number of runs of homozygosity (RoH) compared with the neighboring Baltic ringed seal (Pusa hispida botnica) reference population (p < 0.001). There is also a tendency for stillborn seal pups to have more pronounced RoH. Since the population is divided into semi-isolated subpopulations within the Lake Saimaa exposing the population to deleterious genomic effects, our results support augmented gene flow as a genetic conservation action. Based on our results suggesting inbreeding depression in the population, we recommend Pihlajavesi as a potential source and Southern Saimaa as a potential recipient subpopulation for translocating individuals. The Saimaa ringed seal is a recognized subspecies and therefore translocations should be considered only within the lake to avoid an unpredictable risk of disease, the introduction of deleterious alleles, and severe ecological issues for the population.

Museum specimens of a landlocked pinniped reveal recent loss of genetic diversity and unexpected population connections.

The Saimaa ringed seal (Pusa hispida saimensis) is endemic to Lake Saimaa in Finland. The subspecies is thought to have originated when parts of the ringed seal population of the Baltic region were trapped in lakes emerging due to postglacial bedrock rebound around 9000 years ago. During the 20th century, the population experienced a drastic human-induced bottleneck. Today encompassing a little over 400 seals with extremely low genetic diversity, it is classified as endangered. We sequenced sections of the mitochondrial control region from 60 up to 125-years-old museum specimens of the Saimaa ringed seal. The generated dataset was combined with publicly available sequences. We studied how genetic variation has changed through time in this subspecies and how it is phylogenetically related to other ringed seal populations from the Baltic Sea, Lake Ladoga, North America, Svalbard, and the White Sea. We observed temporal fluctuations in haplotype frequencies and loss of haplotypes accompanied by a recent reduction in female effective population size. In apparent contrast with the traditionally held view of the Baltic origin of the population, the Saimaa ringed seal mtDNA variation also shows affinities to North American ringed seals. Our results suggest that the Saimaa ringed seal has experienced recent genetic drift associated with small population size. The results further suggest that extant Baltic ringed seal is not representative of the ancestral population of the Saimaa ringed seal, which calls for re-evaluation of the deep history of this subspecies.

Characteristics of ringed seal Pusa hispida (‘natchiq’) denning habitat in Kotzebue Sound, Alaska, during a year of limited sea ice and snow

Sea ice and snow are essential to Arctic ecosystems, playing key roles in the lives of Arctic marine mammals and the Indigenous Peoples who rely on them. Ringed seals Pusa hispida (‘natchiq’ in Iñupiaq) use snow-covered dens on sea ice for pupping, but quantitative information on denning habitat requirements is limited, and it is unknown how changes in snow depth and sea-ice extent will impact ringed seals. Here, an Indigenous Elder Advisory Council and a multidisciplinary group of scientists used knowledge co-production to quantify fine-scale ringed seal habitat selection patterns in Kotzebue Sound, Alaska (USA), during a year of unprecedentedly limited snow and sea-ice availability. Together, we conducted unoccupied aerial vehicle-based surveys during spring 2019 and related seal counts to survey date, bathymetry, and novel proxies for snow depth and surface roughness that we derived from Landsat 8 surface reflectance and validated with on-ice measurements. Generalized additive models showed that counts of seal groups (all age classes) and pups were associated with later survey dates, deeper water, and habitat with bright Landsat 8 pixel values and intermediate pixel variability, which in turn were correlated with deep snow and surface roughness. We observed shallow snow depths, early sea-ice breakup, and high seal densities consistent with the extreme lack of ice available in 2019. Indigenous Knowledge, intentionally woven with scientific data, provided novel and more nuanced understandings of snow and sea-ice conditions for seals. Our results may give a glimpse at future ringed seal habitat and selection in a warming Arctic.

Divergent habitat use and the influence of sea ice concentration on the movement behaviour of ringed seals Pusa hispida in Labrador, Canada

Climate change and industrial activities are leading to significant ecological changes in the Eastern Canadian Arctic, with consequences for top predators, including ringed seals Pusa hispida. However, there remains a limited understanding of habitat use, constraining an understanding of the impacts of change on this culturally valued pinniped. A total of 20 ringed seals from 2 areas in Labrador with different geomorphic attributes (Saglek Fjord in the North, and Lake Melville, an estuarine ‘fjard’ in the South) were equipped with satellite-linked transmitters to characterize behaviour states, home ranges, core use areas and environmental variables. Lake Melville-tagged seals had a smaller home range than Saglek Fjord seals (84968 vs. 196886 km2). There was little spatial overlap in the home ranges (10%) and core use areas (0%) between the 2 areas, which were separated by 572 km. Lake Melville seals spent more time in a transiting state during open water conditions (26%) than during ice-covered periods (9%), probably due to an influence of sea ice concentration; they also spent more time in the area in which they were tagged (72%) than did Saglek Fjord seals (36%), increasing the risk of exposure to local contaminants associated with hydroelectric developments. Our results suggest that ringed seals in Lake Melville have better feeding opportunities but may be more vulnerable to changing ice conditions and contaminants compared to seals in Saglek. These results will support the development of a planned culturally based Marine Protected Area in Nunatsiavut and can inform efforts to remediate contaminant sources in the region.

Maintaining control: metabolism of molting Arctic seals when hauled out and in water.

Seals haul out of water for extended periods during the annual molt, when they shed and regrow their pelage. This behavior is believed to limit heat loss to the environment given increased peripheral blood flow to support tissue regeneration. The degree to which time in water, particularly during the molt, may affect thermoregulatory costs is poorly understood. We measured the resting metabolism of three spotted (Phoca largha), one ringed (Pusa hispida), and one bearded (Erignathus barbatus) seal during and outside the molting period, while resting in water and hauled out. Metabolic rates were elevated in spotted and ringed seals during molt, but comparable in water and air for individuals of all species regardless of molt status. Our data indicate that elevated metabolism during molt primarily reflects the cost of tissue regeneration, while increased haul out behavior is driven by the need to maintain elevated skin temperatures to support tissue regeneration.

Environmental DNA metabarcoding reveals seasonal and spatial variation in the vertebrate fauna of Ilulissat Icefjord, Greenland

Ilulissat Icefjord in Greenland is experiencing the effects of climate change, with the Sermeq Kujalleq glacier being one of the fastest-moving and most productive ice streams in Greenland. This is likely affecting the distribution of species in the fjord, including those important to local fisheries. Due to heavy ice conditions, few studies on environmental and ecological conditions exist from the fjord. However, new techniques such as environmental DNA (eDNA) metabarcoding now allow deeper insight into the fjord system. Here, we combine local ecological knowledge with data on hydrographic conditions, stable isotopes (δ18O), and eDNA metabarcoding to investigate the spatial and seasonal distribution of marine fish and mammals inside Ilulissat Icefjord. Our eDNA results support local observations that Arctic char migrate to the southern fjord during summer, harp seals forage in large herds in the fjord system, polar cod is the dominant prey fish in the area, and Greenland shark likely does not reside in the fjord system. Lower predation pressure in the Icefjord, due to the absence of Greenland shark and polar bears as well as limited fishing/hunting, is presumably one of the reasons why ringed seals and Greenland halibut are larger in the Icefjord. Furthermore, our results indicate that in summer, the southern branch of the fjord system has a more diverse community of vertebrates and different water masses than the northern branch and main fjord, indicating a time lag between inflows to the different branches of the fjord system. Our approach highlights the value of combining local ecological knowledge with scientific research and represents a potential starting point for monitoring biological responses in Ilulissat Icefjord associated with climate-induced changes.

Ішкі Орда (Бөкей Ордасы) хандары мөрлерінің реконструкциясы: мөр символдары мен атрибуттарын анықтау

The seals used by the authorities in the history of Kazakhstan before the twentieth century can be grouped and systematized as follows: seals with archeographic symbols; seals with patterns, 90Т. Картаева, Е. Даубаев, Э. Алтынбекова Turkic Studies Journal 2 (2023) 67-92pictorial signs; seals with a portrait image; coat of arms seals; seals with stamps without the name of the owner; stamps with the name of the owner; relief seals without the name of the owner; relief seals with the name of the owner.Although Kazakh khans and sultans stamped their seals in the form of rings, they did not wear them on their hands every day, and when certifying documents, the pedestal was worn on the finger in the «aynateris» way, i.e. with a pointed head up (a bird’s nose is negative when wearing a «kusmuryn» ring) or certified with holding the pedestal in the hand. But judges, rich people, volost governors, tarkhans, batyrs and elders had round, convex, square or stone seals. The shape, that is the image of the ring seal of the Khans and sultans, corresponded to the image of the top of the military banners. The pommel of the banner and the seal are the attribute of power. The fact that the head part of both attributes of power is directed upwards proves that they were generally recognized in the traditional environment. The originals (originals) of the seals of the Kazakh Khans and sultans have not been preserved under the influence of colonization. The authors share their experience in reconstructing the seal and revealing the mystery of the symbols on the front of the seal.

Research on Dynamic Seal Friction Torque Compensation for a Low-Slow-Small UAV Tracking System

To ensure reliable and accurate operation in a complex field environment for Low-Slow-Small unmanned aerial vehicle (LSS-UAV) tracking systems, a dynamic seal shafting structure consisting of a labyrinthine structure and a magnetic fluid seal ring is designed to protect important equipment, such as the infrared sensor, visible CCD and the laser rangefinder from erosion and oxidation by the external environment. A friction torque model is established for the system’s dynamic seal structure to ensure tracking accuracy of the system. The simulation results show that the closed-loop speed accuracy of the system is improved by nearly 10 fold after adding friction torque compensation. The actual test results show that including friction torque compensation can effectively reduce the start-up delay and speed fluctuation error, and the speed fluctuation error is reduced by more than 80% compared to that without friction torque compensation. The tracking accuracy of the dynamic LSS-UAV is reduced from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$56.44 \mu $ </tex-math></inline-formula> rad to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$14.86 \mu $ </tex-math></inline-formula> rad after adding friction torque compensation, which meets the requirement of smooth and accurate tracking for LSS-UAV tracking systems, and verifies the effectiveness and accuracy of compensation for the dynamic seal friction torque.

Mechanical properties of fluoroplastic seals of axial-piston pumps in relation to the operating conditions of a hydraulic drives

The article considers the issues associated with the elastic and plastic properties of fluoroplastic in the state of delivery and radiation hardened. The statement about the radiation hardening of fluoroplastic improves thermal deformation characteristics is substantiated. The results of kinetic microindentation are studied in comparison with the initial state in the temperature range of 80 - 400 0C. The effect of temperature on the ratio of the work of the elasticity and plasticity forces is analyzed. Particular attention is paid to the elastic properties of fluoroplastic. The assumption is substantiated that it is possible to improve the elastic properties of fluoroplastic by radiation treatment at elevated temperatures, which are typical for high-speed axial piston pumps. On the basis of the study, it was found that the use of radiation hardening treatment of fluoroplastic is promising for increasing the durability of movable seal rings.

Ultrathin Glass-Based Wafer-Level Integration for Miniaturized Hermetic MEMS Application

In this article, a glass-based hermetic structure has been packaged at wafer level with a thickness thinner than 200 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> and a size smaller than 1 mm2, showing the prospective way to realize the miniaturization of microelectromechanical systems (MEMS) with high throughput. For the development of this novel wafer-level packaging platform, material selection of metal wire was studied. Next, the technique of metal patterning on the cavity structure was demonstrated for the fabrication of seal ring and electrical connection simultaneously. At last, the ultrathin hermetic structure was sealed by metal-to-metal bonding at wafer level. These technologies can be widely used in advanced miniaturized packaging applications for next-generation electronic components.

ANALISIS PERAWATAN MESIN POMPA SENTRIFUGAL DENGAN METODE RELIABILITY CENTERED MAINTENANCE

The pump is an energy conversion machine that can move fluid from one place to another through a piping medium by adding energy to the fluid being moved continuously. To find out or minimize the occurrence of pump damage, periodic maintenance is carried out. In the pump type 6P-4021-J which is used in the STG (Steam Turbine Generator) and BB (Coal Boiler) sectors, PT. PUSRI is affected by the dirty condition of the slurry caused by the presence of mud and other so the working efficiency of the pump decreases. Therefore, periodic and routine maintenance or cleaning is required. Maintenance policies that are corrective or reactive, systematic or scheduled, and Condition-Based, all aim to achieve the availability and reliability of equipment and systems by reducing maintenance costs. Reliability Centered Maintenance method is used to analyze the causes of failure with the results of decisions for system maintenance. The critical components of a centrifugal pump include; bearings, seal rings, and impellers. The highest RPN value is the bearing component of 96. The reliability value of the bearing component is 0.468 with an average repair time of 3.32 hours. The recommended maintenance action is to apply lubricant regularly. So that it can reduce wear, prevent corrosion, and control the temperature of the bearing.

Abundance and distribution of the Ladoga ringed seals in anomaly warm winter 2020: results of the arial survey using drones

The aimof this research was to assess the abundance and distribution of the Ladoga ringed seals during anomaly warm winter 2020.The main methodof the research was arial survey of the seals using drones. Taking into account complete absence of ice on the surface of the Ladoga Lake at the time of the survey (April-May, 2020) a new method for assessing the seals abundance was used that was based on the extrapolation of the seals density along the coast line using barrier model in R Statistic Software.As a resultof the research, it was shown that during anomaly warm winter, in the absence of ice fields on the Ladoga Lake, the seals formed rookeries directly on the co0astline of remote islands and hardly accessible rocky inlets in the northern part of the Ladoga Lake. Total number of the seal population, estimated basing on the arial survey data was 5,680 individuals.Conclusion: The study showed that the islands, skerries and rocky inlets in the northern part of the Ladoga Lage act as a kind of refuge for the Ladoga ringed seal during anomaly warm ice-free winters. These environments provide the seals proper substrate suitable for bedding and shelter. Basing on the survey data, the population of the Ladoga seal in the northern part of the Ladoga Lake was amounted to 5,680 individuals which is close to the estimates obtained for the entire Ladoga Lake in 2012–6.5 thousand individuals. Thus, the data of the 2020 air survey allow us to make a preliminary conclusion that the population of the Ladoga seal has not changed significantly over the past 8 years.

Distinct latitudinal community patterns of Arctic marine vertebrates along the East Greenlandic coast detected by environmental DNA

AbstractAimGreenland is one of the places on Earth where the effects of climate change are most evident. The retreat of sea ice has made East Greenland more accessible for longer periods during the year. East Greenland fjords have been notoriously difficult to study due to their remoteness, dense sea ice conditions and lack of infrastructure. As a result, biological monitoring across latitudinal gradients is scarce in East Greenland and relies on sporadic research cruises and trawl data from commercial vessels. We here aim to investigate the transition in fish and marine mammal communities from South to Northeast Greenland using environmental DNA (eDNA).LocationSouth to Northeast Greenland.MethodsWe investigated the transition in fish and marine mammal communities from South to Northeast Greenland using eDNA metabarcoding of seawater samples. We included both surface and mesopelagic samples, collected over approximately 2400 km waterway distance, by sampling from Cape Farewell to Ella Island in August 2021.ResultsWe demonstrate a clear transition in biological communities from south to northeast, with detected fish and mammal species matching known distributions. Samples from the southern areas were dominated by capelin (Mallotus villosus) and redfish (Sebastes), whereas northeastern samples were dominated by polar cod (Boreogadus saida), sculpins (Myoxocephalus) and ringed seal (Pusa hispida). We provide newly generated 12S rRNA barcodes from 87 fish species, bringing the public DNA database closer to full taxonomic coverage for Greenlandic fish species for this locus.Main ConclusionsOur results demonstrate that eDNA sampling can detect latitudinal shifts in marine biological communities of the Arctic region, which can supplement traditional fish surveys in understanding species distributions and community compositions of marine vertebrates. Importantly, sampling of eDNA can be a feasible approach for detecting northward range expansions in remote areas as climate change progresses.