Comets: pre- and post-Halley

1991 ◽  
Vol 9 (2) ◽  
pp. 219-224
Author(s):  
K. S. Krishna Swamy
Keyword(s):  
Solar Wind ◽  
Intensive Study ◽  
Cometary Plasma ◽  
Comet Halley ◽  
Insight Into

AbstractThe recent intensive study of Comet Halley based on in situ measurements, observations carried out with rockets and satellites and supplemented with co-ordinated Earth based observations has not only confirmed pre-Halley results, but also has given new insight into the nature of the nucleus, dust, gas and the interaction of cometary plasma with the solar wind. These observations also have raised many new questions and problems. Several of these aspects will be discussed. For a better understanding of these problems, the planned future missions to comets will also be discussed.

scholarly journals The Global Interaction of Comets with the Solar Wind

1991 ◽  
Vol 116 (2) ◽  
pp. 1125-1144 ◽  
Author(s):  
K. R. Flammer
Keyword(s):  
Solar Wind ◽  
Heliocentric Distance ◽  
Theoretical Models ◽  
Bow Shock ◽  
Flow Transition ◽  
The Sun ◽  
In Situ Observations ◽  
Comet Halley

AbstractThe global interaction of the solar wind with a comet as it orbits the Sun is reviewed. After a brief survey of the flow transition regions observed at comet Halley is presented, theoretical models are given for the cometocentric distance of the bow shock, the cometopause, and the ionopause. In addition, predictions are made as to what heliocentric distance these boundaries should form at. The results of these models are compared with the in situ observations at comet Halley.

Magnetic fields and charged particles around major planets and their satellites

1981 ◽  
Vol 303 (1477) ◽  
pp. 247-260 ◽  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Small Volume ◽  
Magnetic Moments ◽  
Charged Particles ◽  
The Moon ◽  
Planetary Rotation ◽  
Spacecraft Data ◽  
Insight Into

Jupiter and Saturn have magnetospheres whose large-scale structure can be understood by analogy with Earth, but the ways in which the magnetospheres differ are of great interest. At Earth, large-scale processes are dominated by convective plasma flows driven by the solar wind. At Jupiter, centrifugal effects driven by planetary rotation are critical. Magnetosphere particle sources include not only the ionosphere and the solar wind (as at Earth) but also satellites and rings. The internal planetary magnetic moments that control the scale of the magnetosphere differ by orders of magnitude between Jupiter and Earth. The magnetic moments have been modelled from spacecraft data but the restricted spatial sampling biases the results and limits confidence in details of the models. Because Jupiter is the only accessible protostar, it serves as a laboratory to test how well inferences from ground-based observations accord with in situ measurements. The agreement in some cases examined is reassuringly good but remote observations probe less than 0.1 % of the magnetospheric volume. Within that small volume, strong currents couple the moon lo with Jupiter s ionosphere. Voyager data give new insight into the lo story and suggest that lo may itself be magnetized and surrounded by an entirely unfamiliar type of magnetosphere.

scholarly journals The International Cometary Explorer (ICE) Mission to comet Giacobini-Zinner (G/Z)

1985 ◽  
Vol 83 ◽  
pp. 405-414
Author(s):  
J.C. Brandt ◽  
R.W. Farquhar ◽  
S.P. Maran ◽  
M.B. Niedner ◽  
T. von Rosenvinge
Keyword(s):  
Solar Wind ◽  
September 11 ◽  
Solar Wind Interaction ◽  
Downstream Side ◽  
Pass Through ◽  
Comet Halley

AbstractThe ICE spacecraft will pass through the tail of P/Giacobini-Zinner on September 11, 1985, to make in situ measurements of particles, fields, and waves that will contribute significantly to the knowledge of plasma tails and other aspects of the cometary/solar wind interaction. By obtaining data on the downstream side of G/Z, the ICE will complement the later upstream measurements obtained by the Comet Halley probes.

scholarly journals Development of Fragility Curves for Piping and Slope Stability of River Levees

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 738
Author(s):  
Nicola Rossi ◽  
Mario Bačić ◽  
Meho Saša Kovačević ◽  
Lovorka Librić
Keyword(s):  
Slope Stability ◽  
Fragility Curves ◽  
Safety Margin ◽  
Water Levels ◽  
Flood Event ◽  
Soil Parameters ◽  
Design Code ◽  
A Site ◽  
Insight Into

The design code Eurocode 7 relies on semi-probabilistic calculation procedures, through utilization of the soil parameters obtained by in situ and laboratory tests, or by the means of transformation models. To reach a prescribed safety margin, the inherent soil parameter variability is accounted for through the application of partial factors to either soil parameters directly or to the resistance. However, considering several sources of geotechnical uncertainty, including the inherent soil variability, measurement error and transformation uncertainty, full probabilistic analyses should be implemented to directly consider the site-specific variability. This paper presents the procedure of developing fragility curves for levee slope stability and piping as failure mechanisms that lead to larger breaches, where a direct influence of the flood event intensity on the probability of failure is calculated. A range of fragility curve sets is presented, considering the variability of levee material properties and varying durations of the flood event, thus providing crucial insight into the vulnerability of the levee exposed to rising water levels. The procedure is applied to the River Drava levee, a site which has shown a continuous trend of increased water levels in recent years.

Insight into the enhanced photocatalytic properties of AgBr/Ag4P2O7 composites synthesized via in situ ion exchange reaction

2021 ◽  
Vol 9 (1) ◽  
pp. 104889
Author(s):  
Wyllamanney da S. Pereira ◽  
Fabrício B. Destro ◽  
Cipriano B. Gozzo ◽  
Edson R. Leite ◽  
Júlio C. Sczancoski
Keyword(s):  
Ion Exchange ◽  
Exchange Reaction ◽  
Photocatalytic Properties ◽  
Ion Exchange Reaction ◽  
Insight Into

scholarly journals In situ synthesis of methane using Ag–GDC composite electrodes in a tubular solid oxide electrolytic cell: new insight into the role of oxide ion removal

2021 ◽  
Vol 5 (7) ◽  
pp. 2055-2064
Author(s):  
Saheli Biswas ◽  
Aniruddha P. Kulkarni ◽  
Daniel Fini ◽  
Sarbjit Giddey ◽  
Sankar Bhattacharya
Keyword(s):  
Electrolytic Cell ◽  
Composite Electrodes ◽  
Ion Removal ◽  
Single Temperature ◽  
Methanation Catalyst ◽  
Oxide Ion ◽  
Insight Into ◽  
Electrochemical Phenomenon

In situ synthesis of methane in a single-temperature zone SOEC in the absence of any methanation catalyst is a completely electrochemical phenomenon governed by the thermodynamic equilibrium of various reactions.

In situ loading of well-dispersed silver nanoparticles on nanocrystalline magnesium oxide for real-time monitoring of catalytic reactions by surface enhanced Raman spectroscopy

Nanoscale ◽  
2015 ◽  
Vol 7 (40) ◽  
pp. 16952-16959 ◽  
Author(s):  
Kaige Zhang ◽  
Gongke Li ◽  
Yuling Hu
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Catalytic Reactions ◽  
Reaction Intermediates ◽  
Reaction Conditions ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Nanocrystalline Magnesium Oxide ◽  
Insight Into

The surface-enhanced Raman spectroscopy (SERS) technique is of great importance for insight into the transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions under actual reaction conditions, especially in water.

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