scholarly journals Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment

10.3791/61789 ◽  
2021 ◽  
Author(s):  
Ninos Hermis ◽  
Gabriel LeBlanc ◽  
Laura M. Barge
Keyword(s):  
Thermal Gradient ◽  
Early Earth ◽  
Gradient Environment

Fission Gas Bubbles in Fractured UO2

1968 ◽  
Vol 26 ◽  
pp. 286-287
Author(s):  
O. M. Katz
Keyword(s):  
Electron Microscopy ◽  
Thermal Gradient ◽  
Gas Bubbles ◽  
Inert Gas ◽  
Thermal Gradients ◽  
Fission Gas ◽  
Beam Heating ◽  
Limited Application ◽  
Bubble Characteristics ◽  
Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

Making vinegar on the early earth

Nature ◽  
2000 ◽  
Author(s):  
Philip Ball
Keyword(s):  
Early Earth

FIELD FORUM REPORT: Processes on the Early Earth

GSA Today ◽  
2004 ◽  
Vol 14 (11) ◽  
pp. 28 ◽  
Author(s):  
Wolf Uwe Reimold ◽  
Carl R. Anhaeusser ◽  
Ken A. Eriksson ◽  
Axel Hofmann ◽  
Roger L. Gibson ◽  
...  
Keyword(s):  
Early Earth

THERMAL ALTERATION OF PRECAMBRIAN MICROFOSSILS: APPLICATIONS TO THE STUDY OF STABLE CARBON ISOTOPES ON THE EARLY EARTH

2020 ◽  
Author(s):  
Jeffrey Osterhout ◽  
◽  
J. William Schopf ◽  
Anatoliy B. Kudryavtsev ◽  
K.D. McKeegan
Keyword(s):  
Carbon Isotopes ◽  
Stable Carbon Isotopes ◽  
Early Earth ◽  
Stable Carbon ◽  
Thermal Alteration

Toward living nanomachines

2018 ◽  
Author(s):  
Christof Mast ◽  
Friederike Möller ◽  
Moritz Kreysing ◽  
Severin Schink ◽  
Benedikt Obermayer ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Thermal Gradient ◽  
Molecular Level ◽  
Minimal System ◽  
Thermal Gradients ◽  
Temperature Oscillations ◽  
Fluid Convection ◽  
Inanimate Matter ◽  
High Concentrations ◽  
Periodic Temperature

How does inanimate matter become transformed into animate matter? Living systems evolve by replication and selection at the molecular level and this chapter considers how to establish a synthetic, minimal system that can support molecular evolution and thus life. Molecular evolution cannot be explained by starting with high concentrations of activated chemicals that react toward their chemical equilibrium; persistent non-equilibria are required to maintain continuous reactivity and we especially consider thermal gradients as an early driving force for Darwinian molecular evolution. The temperature difference across water-filled compartments implements a laminar fluid convection with periodic temperature oscillations that allow for the melting and replication of DNA. Simultaneously, dissolved molecules are moved along the thermal gradient by an effect called thermophoresis. The combined result is an efficient molecule trap that exponentially favors long over short DNA and thus maintains complexity. Future experiments will reveal how thermal gradients could actively drive the Darwinian process of replication and selection.

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