Phyllozoon and Aulozoon: key components of a novel Ediacaran death assemblage in Bathtub Gorge, Heysen Range, South Australia

The recognition of fossiliferous horizons both below and above the classical Ediacara levels of the Flinders Ranges, South Australia, significantly expands the potential of this candidate World Heritage succession. Here we document a small window into the biology and taphonomy of the late Ediacaran seafloor within the new Nilpena Sandstone Member of the Rawnsley Quartzite in Bathtub Gorge, northern Heysen Range. A 1 m2 slab extracted from the gorge, now on permanent display at the South Australian Museum, has a death assemblage dominated by the erniettomorph Phyllozoon hanseni Jenkins and Gehling 1978 and a newly named macroscopic tubular body fossil – Aulozoon soliorum gen. et sp. nov. – on its fine sandstone bed sole. The orientations and juxtaposition of these taxa suggest overprinting of an in situ benthic Phyllozoon community by sand-filled tubes of Aulozoon carried in by a storm wave-base surge. Phyllozoon hanseni is a widespread species that is restricted to the Nilpena Sandstone Member of the Rawnsley Quartzite, whereas Dickinsonia costata ranges from the underlying Ediacara Sandstone Member into the Nilpena Sandstone Member. Fundamental differences in the ways these two vendobiont taxa are constructed and preserved may provide insights into their biology and phylogenetic affinities. In the Nilpena Sandstone Member, D. costata is joined by Dickinsonia rex Jenkins 1992, which appears to be confined to the member, and is here re-described to clarify its taxonomic status and stratigraphic distribution.

The response of zircon to the extreme pressures and temperatures of a lightning strike

Hypervelocity impacts can produce features in zircon that are not normally produced by endogenic processes. However, lightning can also induce extreme pressure–temperature excursions, and its effect on zircon has not been studied. With the aim to recognise features that form in response to extreme pressure–temperature excursions but are not unique to hypervelocity impacts, we imaged and undertook microstructural characterization of zircon in a fulgurite (a tubular body of glass and fused clasts that formed in response to a lightning strike). We document zircon with granular ZrO2 and rims of vermicular ZrO2, features which vary in abundance with increasing distance from the fulgurite’s central void. This indicates that these features formed in response to the lightning strike. Zircon dissociation to ZrO2 and SiO2 is a high-temperature, relatively low-pressure phenomenon, consistent with previous suggestions that lightning strikes involve extreme temperatures as well as pressures greater than those usually generated in Earth’s crust but rarely > 10 GPa. The rims of monoclinic ZrO2 record crystallographic evidence for precursor cubic ZrO2, demonstrating that cubic ZrO2 is not unique to hypervelocity impacts. Given the likelihood that this fulgurite experienced pressures of, at most, a few GPa, evidence for cubic ZrO2 indicates peak temperatures > 2000 °C.

Analysis of methods of manufacturing of differently multi-directional internal twist grooves of tubular body parts and selection of tools for its implementation

Рассматривается возможность интенсификации процесса изготовления разнонаправленных внутренних винтовых пазов трубных корпусных деталей, используемых в судовых энергоустановках и пусковых устройствах для запуска подводных и летательных беспилотных аппаратов, и их элементов, испытывающих многократные нагрузки в период эксплуатации. Для выбора наиболее рационального и эффективного способа изготовления применен функционально-структурный анализ используемого оборудования для изготовления внутренних винтовых пазов трубных корпусных деталей, с помощью которого найдены закономерности процесса. Выявленный способ обработки, оборудования и применяемый инструмент являются наименее затратными и наиболее эффективными для выполнения необходимых технических требований. При проведении анализа зон локальных деформаций выявлен ряд зависимых величин, влияющих на конечное усилие и степень деформации при изготовлении разнонаправленных внутренних винтовых пазов трубных корпусных деталей. The possibility of intensification of the process of manufacturing of multi-directional internal twist grooves of tubular bodyparts used in ship power plants and launching devices for launch of underwater and aerial unmanned vehicles and their elements experiencing multiple loads during operation is considered. In order to select the most rational and efficient method of manufacturing, functional-structural analysis of used equipment for making internal twist grooves of tubular body parts is used, with the help of which process regularities are found. The identified method of processing, equipment and tool used are the least expensive and most effective to meet the required technical requirements. Analysis of local deformation zones revealed a number of dependent values affecting final force and degree of deformation during manufacture of differently directed internal twist grooves of tubular body parts.

Simulations of Tubular UAV With Vectored Thrust in Near-Hovering Regimes in the Presence of Side Winds

An innovative unmanned aerial vehicle with a tubular body and a vectored thruster is considered in this study. In order to optimize the vehicle design and develop effective means for its control, aerodynamic characteristics of this vehicle need to be known. Computational fluid dynamics studies employing STAR-CCM+ software have been carried out for this UAV in near-hovering regimes. Aerodynamic simulations employed the SST k–ω turbulence model, γ transition model, and a virtual actuator disk model. After conducting a validation study with a cylinder in axial flow, modeling of the UAV setup was completed for a range of propulsor orientations and cross winds. The aerodynamic phenomena are found to become more complex with increasing the propulsor angle with respect to the main body axis and in stronger cross winds due to interactions between the incident flow, the propulsor jet, and the body surface. At the propulsor deflection angle of 15°, the horizontal aerodynamic force on the body was augmented by 0.02–0.07 of the propulsor thrust magnitude in various wind conditions, whereas the axial downward force increased by 0.01–0.03 of the thrust. In cross winds with the relative velocity magnitude of 0.65, the horizontal aerodynamic force on the body increased by about 0.25 of the propulsor thrust magnitude, while the axial downward force increased by about 0.05 of the thrust.