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We collated available satellite telemetry data for six species of ice-associated marine mammals in the Pacific Arctic: ringed seals (Pusa hispida; n = 118), bearded seals (Erignathus barbatus, n = 51), spotted seals (Phoca largha, n = 72), Pacific walruses (Odobenus rosmarus divergens, n = 389); bowhead whales (Balaena mysticetus, n = 46), and five Arctic and sub-arctic stocks of beluga whales (Delphinapterus leucas, n = 103). We also included one seasonal resident, eastern North Pacific gray whales (Eschrichtius robustus, n = 12). This review summarized the distribution of daily locations from satellite-linked transmitters during two analysis periods, summer (May–November) and winter (December–April), and then examined the overlap among species. Six multi-species core use areas were identified during the summer period: 1) Chukotka/Bering Strait; 2) Norton Sound; 3) Kotzebue Sound; 4) the northeastern Chukchi Sea; 5) Mackenzie River Delta/Amundsen Gulf; and 6) Viscount Melville Sound. During the winter period, we identified four multi-species core use areas: 1) Anadyr Gulf/Strait; 2) central Bering Sea; 3) Nunivak Island; and 4) Bristol Bay. During the summer period, four of the six areas were centered on the greater Bering Strait region and the northwestern coast of Alaska and included most of the species we examined. The two remaining summer areas were in the western Canadian Arctic and were largely defined by the seasonal presence of Bering-Chukchi-Beaufort stock bowhead whales and Eastern Beaufort Sea stock beluga whales, whose distribution overlapped during both summer and winter periods. During the winter period, the main multi-species core use area was located near the Gulf of Anadyr and extended northwards through Anadyr and Bering Straits. This area is contained within the Bering Sea “green belt”, an area of enhanced primary and secondary productivity in the Bering Sea. We also described available telemetry data and where they can be found as of 2017. These data are important for understanding ice-associated marine mammal movements and habitat use in the Pacific Arctic and should be archived, with appropriate metadata, to ensure they are available for future retrospective analyses.

Fusion welding of steel pressure vessels provides one of the most economic methods for creating such structures. However, the highly localised heat distribution, at the fused region gives rise to non-uniform heating / expansion and cooling / contraction of the weld and the surrounding base material, consequently giving rise to residual stresses and distortion. Several techniques are available to minimize welding distortions and residual stresses [1]. One feasible and efficient mitigation technique, that alters the inherent residual stresses developed during welding, includes the use of low transformation start temperature welding wire [2e4]. By altering the filler material and metallurgical transformations developed at the fusion zone and heat affected zone, wielded regions at the weld line can give rise to compressive residual stresses [2]. Consequently by establishing the appropriate chemical composition of the welding wire, a significant reduction in welding distortions can be achieved. This study focuses on establishing the merits of using different filler materials to minimize welding residual stresses and distortion through a thermal-metallurgical-elasto-plastic numerical parametric study. Numerical modelling of butt welded structures using three different filler materials is considered and the applicability of using low transformation temperature welding wire is investigated. The predicted residual stresses and distortions give a significant advance in understanding and control of welding distortion in welded fabrications. The chemical composition of the filler material and ultimately fused zone composition, leading to reductions in residual stresses and distortions is identified.

Fusion welding is the most common and convenient method used for the fabrication of large, thin-plate welded structures. However, the resulting tendency to out-of-plane distortion exacts severe design and fabrication penalties in terms of poorer buckling performance, lack of fairness in external appearance, poor fit-up and frequent requirements for expensive rework. This study forms part of a long-term project that has the aim of modelling welding and related fabrication processes computationally with particular emphasis on the out-of-plane distortion outcomes. Throughout the present work the computational models have been cross-referenced to realistic experimental test cases. A repeated finding of the trials was that minor variations in fabrication procedures, were found to have significant effects on distortion. In particular, the pre-fabrication procedures, including spot and tack welding, have a significant effect on the initial out-of-plane distortion leading to differences in distortion of the post-welded structures. The support and clamping conditions during welding and cooling of welded thin-plate structures were also found to have a considerable influence on the final predicted out-of-plane distortion. The outcomes often result in different buckling instability behaviour. This paper concentrates on these aspects and draws on studies of buttwelding between plates of thicknesses 3-8 mm.

This study presents a number of finite-element (FE) models aimed at illustrating the effect of using different modelling strategies for the simulation of the thermo-elasto-plastic stages of the welding process. The main challenge with computational approaches is to model the complex and at times indeterminate nature of the welding process, preferably in a simple and transparent manner. The study uses the example of butt welding thin rectangular plates, the results of main interest being the out-of plane distortion and longitudinal residual stresses. The FE model results are compared to experimental data and simplified analytical algorithms that have been developed and validated in the context of a project to improve the prediction and control of welding distortion in thin welded structures.