Distribution, morphology and magnetic characteristics of near-axis seamounts along the KR1, the easternmost segment of the Australian-Antarctic Ridge

<p>The Australian-Antarctic Ridge (AAR) is the spreading boundary between the Australian and the Antarctic plates, and extended from the Southeast Indian Ridge (SEIR) to the Macquarie Triple Junction (MTJ) of Australian-Antarctic-Pacific plates. The KR1 is the easternmost segment of AAR, with a quite large variation in axial morphology. In this study, we identified 3-volcanic seamount chains aligned linearly parallel to the spreading direction of the KR1. The spatial distribution, morphology and summit types for the isolated volcanic structures composing the seamount chains were determined. Eastern seamount chain has the 3-isolated volcanoes which are significantly steep and located at a considerable distance away from the ridge-axis. The central seamount chain is morphologically connected to the ridge-axis, and relatively small and less isolated compared to the other seamount chains. Western seamount chain shows a massive volcanic eruption with significantly large volcanic structures. In usual, a seamount is formed on pre-existing seafloor, and the observed magnetic signal of the seamount is correspond to that of the underlying seafloor when the seamount formation occurs nearly simultaneously with the formation of the underlying seafloor. However, if the observed magnetic anomalies of the seamount have a large misfit or/and reversed geomagnetic polarities with respect to the modeled magnetic anomalies of the underlying seafloor, it implies that there is a sufficiently large temporal gap between the formations of the seamount and the underlying seafloor. Applying this assumption, we forced the relatively younger geomagnetic history to move into the seamount having such misfits, and finally reduced the misfits. As a result, our magnetic model for the seamount chains shows that the isolated volcanoes were mostly originated from off-axis volcanisms of 7~20 km, and have a time span of less than ~600 kyrs to build. In particular, it is assumed that the seamount formations were intensively active during four-periods of 0.3~0.8 Ma, 0.9~1.1 Ma, 1.6~2.1 Ma and 2.2~2.7 Ma.</p>

The structure of dislocations in hemp (Cannabis sativa L.) fibres and implications for mechanical behaviour

Elementary fibres isolated from mechanically processed technical hemp were axially sectioned and imaged with transmission electron microscopy (TEM) to reveal details of the axial morphology of dislocations in the fibre. The overall aim was to investigate the detailed axial structural changes that the fibres undergo during processing, to help better understand the alterations in the deformation behaviour the fibres undergo following processing. The images showed the structure and morphology of dislocations as well as the different forms of damage that processing produced in the fibre structure, such as misalignment of the microfibrils, delamination, and buckled cellulose microfibrils. Furthermore, the results of this work show the ability that axial sectioning of the fibre has to reveal new details of the cell wall structure of hemp to offer new insights in the study of the fibre structure. In turn, the results of this work may help explain the mechanical behaviour of the fibres when they are loaded, as well as help explain the greater chemical accessibility of dislocations, for example, when the fibre is acid hydrolysed.

Vertebral morphometrics and lung structure in non-avian dinosaurs

The lung-air sac system of modern birds is unique among vertebrates. However, debate surrounds whether an avian-style lung is restricted to birds or first appeared in their dinosaurian ancestors, as common osteological correlates for the respiratory system offer limited information on the lungs themselves. Here, we shed light on these issues by using axial morphology as a direct osteological correlate of lung structure, and quantifying vertebral shape using geometric morphometrics in birds, crocodilians and a wide range of dinosaurian taxa. Although fully avian lungs were a rather late innovation, we quantitatively show that non-avian dinosaurs and basal dinosauriforms possessed bird-like costovertebral joints and a furrowed thoracic ceiling. This would have immobilized the lung's dorsal surface, a structural prerequisite for a thinned blood-gas barrier and increased gas exchange potential. This could have permitted high levels of aerobic and metabolic activity in dinosaurs, even in the hypoxic conditions of the Mesozoic, contributing to their successful radiation.

Study on Influence of Crimping Performance of PET/PTT Self-Crimp Yarn Treated with Moist Heat

PET/PTT conjugate yarn has a three-dimension spiral and permanent crimp, which endow the yarn and loomage with excellent performances of crimp extension and crimp recovery. The residual deformation and internal stress of the self-crimp yarn can be eliminated after the moist heat treatment, in order to develop the favorable crimp extension and crimp recovery of the self-crimp yarn, and to give the loomage soft handle and good dimension stability. Crimp shrinkage, crimp module, etc, of the different types of PET/PTT yarn, were tested, and the axial morphology of the yarn was observed, to investigate the effect of linear density, moist heat temperature on PET/PTT yarn.