The precipitation of energetic heavy ions into the upper atmosphere of Jupiter

Evidence for auroral particle precipitation at Jupiter was provided by the ultraviolet spectrometers onboard the Voyagers 1 and 2 spacecraft and by the International Ultraviolet Explorer (IUE). Magnetospheric measurements made by instruments onboard the Voyager spacecraft show that energetic sulfur and oxygen ions are precipitating into the upper atmosphere of Jupiter. A theoretical model has been constructed describing the interaction of precipitating oxygen with the Jovian atmosphere. The auroral energy is deposited in the atmosphere by means of ionization, excitation, and dissociation and heating of the atmospheric gas. Energetic ion and electron precipitation are shown to have similar effects on the atmosphere and ionosphere of Jupiter

The dynamic mature of the Adams ring arcs - Fraternite, Egalite (2,1), Liberte, Courage

By considering the finite mass of Fraternite, the dynamic nature of the Adams ring arcs is regarded as caused by the reaction of a test body (a minor arc) through the Lindblad resonance (LR). Assumming the eccentricity of the test body is larger than that of Galatea, this generates several locations along the ring in the neighborhood of Fraternite where the time averaged force on a test body vanishes. These locations appear to correspond to the time dependent configuration of Egalite (2,1), Liberte, and Courage, and seem to be able to account for the dynamics of the arcs. Such a configuration is a dynamic one because the minor arcs are not bounded by the corotation eccentricity resonance (CER) externally imposed by Galatea, but are self-generated by LR reacting to the external fields

Oxidation on the Nickel Hydroxide Electrode

It has been shown that in alkaline solution alcoholic hydroxyl is oxidized by the charged nickel hydroxide electrode - similarly as by oxidation in the presence of nickel salt catalysts or by »nickel peroxide« - to carboxylic acid. An electrochemical method has been devised for the study of the reaction rate, based on the potentiometric indication of the depletion of NiOOH. It has been shown that the reaction rate is proportional to the amount of NiOOH and the concentration of the alcohol, but independent of the hydroxide ion concentration and the electrode potential. An electrochemical procedure has been devised for the practical implementation of oxidation on NiOOH. In this way a number of primary alcohols may be oxidized with good yields. It has been shown that the oxidation of the vitamin C intermediate di-0-isopropylidene-sorbose can be performed electrochemically with yields above 950/o and, according to estimates, economically on an industrial scale

Gas-grain energy transfer in solar nebula shock waves: Implications for the origin of chondrules

Meteoritic chondrules provide evidence for the occurrence of rapid transient heating events in the protoplanetary nebula. Astronomical evidence suggests that gas dynamic shock waves are likely to be excited in protostellar accretion disks by processes such as protosolar mass ejections, nonaxisymmetric structures in an evolving disk, and impact on the nebula surface of infalling 'clumps' of circumstellar gas. Previous detailed calculations of gas-grain energy and momentum transfer have supported the possibility that such shock waves could have melted pre-existing chondrule-sized grains. The main requirement for grains to reach melting temperatures in shock waves with plausibly low Mach numbers is that grains existed in dust-rich zones (optical depth greater than 1) where radiative cooling of a given grain can be nearly balanced by radiation from surrounding grains. Localized dust-rich zones also provide a means of explaining the apparent small spatial scale of heating events. For example, the scale size of at least some optically thick dust-rich zones must have been relatively small (less than 10 kilometers) to be consistent with petrologic evidence for accretion of hot material onto cold chondrules. The implied number density of mm-sized grains for these zones would be greater than 30 m(exp -3). In this paper, we make several improvements of our earlier calculations to include radiation self-consistently in the shock jump conditions, and we include heating of grains due to radiation from the shocked gas. In addition, we estimate the importance of momentum feedback of dust concentrations onto the shocked gas which would tend to reduce the efficiency of gas dynamic heating of grains in the center of the dust cloud

Cubesat Electrostatic Dust Analyzer (CEDA) for Measuring Regolith Dust Transport on Airless Bodies

The CubeSat Electrostatic Dust Analyzer (CEDA) is developed by the Dust BUSTER student team at the University of Colorado for exploring electrostatic dust transport processes on the surfaces of airless bodies such as asteroids and the Moon. CEDA is a 6U cubesat that consists of a 2U dust analyzer module and an autonomous repositioning system (ARS). This instrument measures the charge, velocity, and mass of lofted dust particles, and provides the lofting rate in order to estimate the efficiency of electrostatic dust transport in surface processes. The dust analyzer module consists of two Dust Trajectory Sensor (DTS) units with a Deflection Field Electrodes (DFE) unit in between them. A dust particle can enter from either end of the analyzer and its charge and velocity are measured using the wire-electrodes on which the charge is induced as the particle passes through. The charged particle is deflected in the DFE where its mass is determined from the deflection trajectory. The ARS, consisting of the sun sensors, cover doors and tilting mechanisms, repositions the instrument for optimized dust measurement on the surface. The communication needs to be provided by the mother spacecraft

Human attention target estimation and application on images

Most computer vision applications, such as automatic image cropping and attention target estimation, aim to perform or solve a task as humans would. While recent works using Neural Networks showed promising results in numerous research areas, complex and subjective tasks are still challenging to solve by only deriving information from images and videos. Therefore to enhance the ability of the machine to localise a part of an image or to interpret complex social interactions between multiple people in the scene like humans would, explicit or implicit user input could be integrated into the algorithm. This thesis investigates the usefulness of explicit verbal and implicit non-verbal human social clues and their combination in frameworks designed for attention-based computer vision tasks. The proposed computational methods in this thesis aim to better understand the user’s intention through different input modalities. Specifically, this work used natural language and its combination with eye-tracking user inputs for description-based image cropping and visual attention for joint attention target estimation. This work studied how a natural language expression of the users could be directly used to automatically localise the described part of an image and output an aesthetically pleasing image crop. The proposed solution re-purposed existing deep learning models into a single optimisation framework to solve this complex, highly subjective problem. In addition to the explicit language expressions and a semi-direct social clue, the eye movements of the users were integrated into a novel multi-modal framework. Finally, motivated by the usefulness of the user’s semi-direct attention input, a deep neural network was developed for estimating attention targets in images to detect and follow the joint attention target of the subjects within the scene. The presented approaches have achieved state-of-the-art performances in quantitative and qualitative measures on different benchmark datasets in their respective research areas. Furthermore, the conducted studies confirmed that the users favoured the output of the proposed solutions. These findings prove that integrating explicit or implicit user input and their combination into computational methods can produce more human-like outputs

Multi-Modal Gaze Following in Conversational Scenarios

Gaze following estimates gaze targets of in-scene person by understanding human behavior and scene information. Existing methods usually analyze scene images for gaze following. However, compared with visual images, audio also provides crucial cues for determining human behavior.This suggests that we can further improve gaze following considering audio cues. In this paper, we explore gaze following tasks in conversational scenarios. We propose a novel multi-modal gaze following framework based on our observation ``audiences tend to focus on the speaker''. We first leverage the correlation between audio and lips, and classify speakers and listeners in a scene. We then use the identity information to enhance scene images and propose a gaze candidate estimation network. The network estimates gaze candidates from enhanced scene images and we use MLP to match subjects with candidates as classification tasks. Existing gaze following datasets focus on visual images while ignore audios.To evaluate our method, we collect a conversational dataset, VideoGazeSpeech (VGS), which is the first gaze following dataset including images and audio. Our method significantly outperforms existing methods in VGS datasets. The visualization result also prove the advantage of audio cues in gaze following tasks. Our work will inspire more researches in multi-modal gaze following estimation

Scientific Preparations for Lunar Exploration with the European Lunar Lander

This paper discusses the scientific objectives for the ESA Lunar Lander Mission, which emphasise human exploration preparatory science and introduces the model scientific payload considered as part of the on-going mission studies, in advance of a formal instrument selection.Comment: Accepted for Publication in Planetary and Space Science 51 pages, 8 figures, 1 tabl

Solar Wind Electron Interaction with the Dayside Lunar Surface and Crustal Magnetic Fields: Evidence for Precursor Effects

Electron distributions measured by Lunar Prospector above the dayside lunar surface in the solar wind often have an energy dependent loss cone, inconsistent with adiabatic magnetic reflection. Energy dependent reflection suggests the presence of downward parallel electric fields below the spacecraft, possibly indicating the presence of a standing electrostatic structure. Many electron distributions contain apparent low energy (<100 eV) upwardgoing conics (58% of the time) and beams (12% of the time), primarily in regions with non-zero crustal magnetic fields, implying the presence of parallel electric fields and/or wave-particle interactions below the spacecraft. Some, but not all, of the observed energy dependence comes from the energy gained during reflection from a moving obstacle; correctly characterizing electron reflection requires the use of the proper reference frame. Nonadiabatic reflection may also play a role, but cannot fully explain observations. In cases with upward-going beams, we observe partial isotropization of incoming solar wind electrons, possibly indicating streaming and/or whistler instabilities. The Moon may therefore influence solar wind plasma well upstream from its surface. Magnetic anomaly interactions and/or non-monotonic near surface potentials provide the most likely candidates to produce the observed precursor effects, which may help ensure quasi-neutrality upstream from the Moon