scholarly journals Pickup ion measurements by MAVEN: A diagnostic of photochemical oxygen escape from Mars

2014 ◽  
Vol 41 (14) ◽  
pp. 4812-4818 ◽  
Author(s):  
A. Rahmati ◽  
T. E. Cravens ◽  
A. F. Nagy ◽  
J. L. Fox ◽  
S. W. Bougher ◽  
...  
Keyword(s):  
Oxygen Escape

scholarly journals Atmospheric loss from the dayside open polar region and its dependence on geomagnetic activity: implications for atmospheric escape on evolutionary timescales

2017 ◽  
Vol 35 (3) ◽  
pp. 721-731 ◽  
Author(s):  
Rikard Slapak ◽  
Audrey Schillings ◽  
Hans Nilsson ◽  
Masatoshi Yamauchi ◽  
Lars-Göran Westerberg ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Polar Region ◽  
Geomagnetic Storms ◽  
Atmospheric Oxygen ◽  
Atmospheric Escape ◽  
Order Of Magnitude ◽  
Ancient Times ◽  
Oxygen Escape ◽  
Atmospheric Loss ◽  
Activity Condition

Abstract. We have investigated the total O+ escape rate from the dayside open polar region and its dependence on geomagnetic activity, specifically Kp. Two different escape routes of magnetospheric plasma into the solar wind, the plasma mantle, and the high-latitude dayside magnetosheath have been investigated separately. The flux of O+ in the plasma mantle is sufficiently fast to subsequently escape further down the magnetotail passing the neutral point, and it is nearly 3 times larger than that in the dayside magnetosheath. The contribution from the plasma mantle route is estimated as  ∼ 3. 9 × 1024exp(0. 45 Kp) [s−1] with a 1 to 2 order of magnitude range for a given geomagnetic activity condition. The extrapolation of this result, including escape via the dayside magnetosheath, indicates an average O+ escape of 3 × 1026 s−1 for the most extreme geomagnetic storms. Assuming that the range is mainly caused by the solar EUV level, which was also larger in the past, the average O+ escape could have reached 1027–28 s−1 a few billion years ago. Integration over time suggests a total oxygen escape from ancient times until the present roughly equal to the atmospheric oxygen content today.

Structure and electrical properties of the new pyrochlore-type protonic solid electrolyte K0.88Nb2O7.58H4.28

2010 ◽  
Vol 66 (6) ◽  
pp. 594-602 ◽  
Author(s):  
O. Smirnova ◽  
N. Kumada ◽  
T. Takei ◽  
Y. Yonesaki ◽  
M. Yashima ◽  
...  
Keyword(s):  
Water Solubility ◽  
Ambient Air ◽  
Structural Formula ◽  
Water Molecules ◽  
Potassium Ions ◽  
The Novel ◽  
X Ray Diffraction ◽  
Stability Range ◽  
Pyrochlore Type ◽  
Oxygen Escape

Single-crystal, synchrotron powder X-ray diffraction and neutron powder diffraction studies of the novel pyrochlore-type compound with the structural formula K0.88(OH)0.54H1.66(H2O)1.04Nb2O6 suggests that the water molecules are located in 32e sites, and the hydroxide ions and potassium ions are located in 16d sites with a significant amount of `free' protons in 96g sites. The total weight loss at temperatures up to 773 K is only about 8%, suggesting the oxygen escape from 48f sites can be excluded and `free' protons must be preserved in the structure. The bulk conductivity in ambient air reaches 10−2 S cm−1 at 623 K. Owing to the extended stability range and resistance to water solubility, the compound can be considered as a candidate for intermediate temperature solid-oxide fuel-cell applications.

scholarly journals Flooding tolerance: suites of plant traits in variable environments

2009 ◽  
Vol 36 (8) ◽  
pp. 665 ◽  
Author(s):  
T. D. Colmer ◽  
L. A. C. J. Voesenek
Keyword(s):  
Plant Traits ◽  
Anoxia Tolerance ◽  
Submergence Tolerance ◽  
Low Oxygen ◽  
Adaptive Traits ◽  
Soil Waterlogging ◽  
Long Duration ◽  
Variable Environments ◽  
Different Depths ◽  
Oxygen Escape

Flooding regimes of different depths and durations impose selection pressures for various traits in terrestrial wetland plants. Suites of adaptive traits for different flooding stresses, such as soil waterlogging (short or long duration) and full submergence (short or long duration – shallow or deep), are reviewed. Synergies occur amongst traits for improved internal aeration, and those for anoxia tolerance and recovery, both for roots during soil waterlogging and shoots during submergence. Submergence tolerance of terrestrial species has recently been classified as either the Low Oxygen Quiescence Syndrome (LOQS) or the Low Oxygen Escape Syndrome (LOES), with advantages, respectively, in short duration or long duration (shallow) flood-prone environments. A major feature of species with the LOQS is that shoots do not elongate upon submergence, whereas those with the LOES show rapid shoot extension. In addition, plants faced with long duration deep submergence can demonstrate aspects of both syndromes; shoots do not elongate, but these are not quiescent, as new aquatic-type leaves are formed. Enhanced entries of O2 and CO2 from floodwaters into acclimated leaves, minimises O2 deprivation and improves underwater photosynthesis, respectively. Evolution of ‘suites of traits’ are evident in wild wetland species and in rice, adapted to particular flooding regimes.

scholarly journals Venus Express observations of atmospheric oxygen escape during the passage of several coronal mass ejections

2008 ◽  
Vol 113 ◽  
Author(s):  
J. G. Luhmann ◽  
A. Fedorov ◽  
S. Barabash ◽  
E. Carlsson ◽  
Y. Futaana ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Atmospheric Oxygen ◽  
Venus Express ◽  
Oxygen Escape

scholarly journals Addressing voltage decay in Li-rich cathodes by broadening the gap between metallic and anionic bands

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jicheng Zhang ◽  
Qinghua Zhang ◽  
Deniz Wong ◽  
Nian Zhang ◽  
Guoxi Ren ◽  
...  
Keyword(s):  
Low Voltage ◽  
Lattice Oxygen ◽  
Oxygen Release ◽  
Voltage Decay ◽  
Redox Active ◽  
Cation Migration ◽  
Voltage Fade ◽  
Oxygen Escape ◽  
Oxygen Bond ◽  
Oxygen Band

AbstractOxygen release and irreversible cation migration are the main causes of voltage fade in Li-rich transition metal oxide cathode. But their correlation is not very clear and voltage decay is still a bottleneck. Herein, we modulate the oxygen anionic redox chemistry by constructing Li2ZrO3 slabs into Li2MnO3 domain in Li1.21Ni0.28Mn0.51O2, which induces the lattice strain, tunes the chemical environment for redox-active oxygen and enlarges the gap between metallic and anionic bands. This modulation expands the region in which lattice oxygen contributes capacity by oxidation to oxygen holes and relieves the charge transfer from anionic band to antibonding metal–oxygen band under a deep delithiation. This restrains cation reduction, metal–oxygen bond fracture, and the formation of localized O2 molecule, which fundamentally inhibits lattice oxygen escape and cation migration. The modulated cathode demonstrates a low voltage decay rate (0.45 millivolt per cycle) and a long cyclic stability.

scholarly journals Oxygen escape from the Earth during geomagnetic reversals: Implications to mass extinction

2014 ◽  
Vol 394 ◽  
pp. 94-98 ◽  
Author(s):  
Yong Wei ◽  
Zuyin Pu ◽  
Qiugang Zong ◽  
Weixing Wan ◽  
Zhipeng Ren ◽  
...  
Keyword(s):  
Mass Extinction ◽  
The Earth ◽  
Oxygen Escape

scholarly journals Estimating the fate of oxygen ion outflow from the high-altitude cusp

2020 ◽  
Vol 38 (2) ◽  
pp. 491-505 ◽  
Author(s):  
Patrik Krcelic ◽  
Stein Haaland ◽  
Lukas Maes ◽  
Rikard Slapak ◽  
Audrey Schillings
Keyword(s):  
High Altitude ◽  
Geomagnetic Activity ◽  
Plasma Sheet ◽  
Geomagnetic Storms ◽  
Strong Dependence ◽  
Activity Levels ◽  
Ion Outflow ◽  
Oxygen Ions ◽  
Magnetic Field Model ◽  
Oxygen Escape

Abstract. We have investigated the oxygen escape-to-capture ratio from the high-altitude cusp regions for various geomagnetic activity levels by combining EDI and CODIF measurements from the Cluster spacecraft. Using a magnetic field model, we traced the observed oxygen ions to one of three regions: plasma sheet, solar wind beyond a distant X-line or dayside magnetosheath. Our results indicate that 69 % of high-altitude oxygen escapes the magnetosphere, from which most escapes beyond the distant X-line (50 % of total oxygen flux). Convection of oxygen to the plasma sheet shows a strong dependence on geomagnetic activity. We used the Dst index as a proxy for geomagnetic storms and separated data into quiet conditions (Dst>0 nT), moderate conditions (0>Dst>-20 nT), and active conditions (Dst<-20 nT). For quiet magnetospheric conditions we found increased escape due to low convection. For active magnetospheric conditions we found an increase in both parallel velocities and convection velocities, but the increase in convection velocities is higher, and thus most of the oxygen gets convected into the plasma sheet (73 %). The convected oxygen ions reach the plasma sheet in the distant tail, mostly beyond 50 RE.

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