scholarly journals Light elements in the core: Effects of impurities on the phase diagram of iron

2008 ◽  
Vol 35 (5) ◽  
Author(s):  
Alexander S. Côté ◽  
Lidunka Vočadlo ◽  
John P. Brodholt
Keyword(s):  
Phase Diagram ◽  
Light Elements ◽  
The Core

Inefficient compaction in small planetary cores -- application to the Moon

2021 ◽  
Author(s):  
Marine Lasbleis
Keyword(s):  
Magnetic Field ◽  
Latent Heat ◽  
Energy Budget ◽  
Inner Core ◽  
Light Elements ◽  
The Moon ◽  
Small Bodies ◽  
Typical Size ◽  
The Core ◽  
Planetary Cores

<div> <p>Growth of the solid inner core is generally considered to power the Earth's present geodynamo. Cristallisation of a solid central inner core has also been proposed to drive the lunar dynamo and to generate a magnetic field in smaller bodies. In a previous work, we estimated the compaction of planetary cores for different scenarios of growth (with or without supercooling) and different sizes of the inner core. Our main results indicated that small inner cores are unlikely to compact efficiently the liquid trapped during the first steps of the growth.</p> <p>This is especially true for small bodies for which the typical size of the core is similar to the compaction length. The light elements are thus trapped during the cristallisation, reducing the release of latent heat and of light elements. We present here a model to include the effect of an inefficient compaction in the energy budget of a planetary core and investigate the implications for the dynamo evolution in small bodies. We apply this model for the evolution of the core of the Moon. </p> </div>

scholarly journals Tumor invasion as non-equilibrium phase separation

2020 ◽  
Author(s):  
Wenying Kang ◽  
Jacopo Ferruzzi ◽  
Catalina-Paula Spatarelu ◽  
Yu Long Han ◽  
Yasha Sharma ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Phase Separation ◽  
Tumor Invasion ◽  
Single Cells ◽  
Equilibrium Phase ◽  
Three Dimensional ◽  
Ample Evidence ◽  
The Core ◽  
Material State ◽  
Non Equilibrium

ABSTRACTTumor invasion depends upon properties of both cells and of the extracellular matrix (ECM). Despite ample evidence that cancer cells can modulate their material state during invasion, underlying biophysical mechanisms remain unclear. Here, we show the potential for coexistence of – and transition between – solid-like, fluid-like, and gas-like phases in invading breast cancer spheroids. Epithelial spheroids are nearly jammed and solid-like in the core but unjam at the periphery to invade as a fluid-like collective. Conversely, post-metastatic spheroids are unjammed and fluid-like in the core and – depending on ECM density – can further unjam and invade as gas-like single cells, or re-jam to invade as a fluid-like collective. A novel jamming phase diagram predicts material phases that are superficially similar to inanimate systems at thermodynamic equilibrium, but here arising in living systems, which exist far from equilibrium. We suggest that non-equilibrium phase separation may provide a unifying physical picture of tumor invasion.TWO-SENTENCE SUMMARYUsing tumor spheroids invading into an engineered three-dimensional matrix, we show here that the cellular collective exhibits coexistent solid-like, fluid-like, and gas-like phases. The spheroid interior develops spatial and temporal heterogeneities in material phase which, depending upon cell type and matrix density, ultimately result in a variety of phase separation patterns at the invasive front, as captured by a jamming phase diagram.

Metal-silicate fractionation in the deep magma ocean and light elements in the core

2006 ◽  
Vol 70 (18) ◽  
pp. A455
Author(s):  
E. Ohtani ◽  
T. Sakai ◽  
T. Kawazoe ◽  
T. Kondo
Keyword(s):  
Light Elements ◽  
Magma Ocean ◽  
The Core ◽  
Metal Silicate

scholarly journals Constraints on Earth’s inner core composition inferred from measurements of the sound velocity of hcp-iron in extreme conditions

2016 ◽  
Vol 2 (2) ◽  
pp. e1500802 ◽  
Author(s):  
Tatsuya Sakamaki ◽  
Eiji Ohtani ◽  
Hiroshi Fukui ◽  
Seiji Kamada ◽  
Suguru Takahashi ◽  
...  
Keyword(s):  
Sound Velocity ◽  
Inner Core ◽  
Earth Model ◽  
Light Elements ◽  
Earth’S Core ◽  
Heated Sample ◽  
Earth's Core ◽  
The Core ◽  
Core Composition ◽  
Earth’S Inner Core

Hexagonal close-packed iron (hcp-Fe) is a main component of Earth’s inner core. The difference in density between hcp-Fe and the inner core in the Preliminary Reference Earth Model (PREM) shows a density deficit, which implies an existence of light elements in the core. Sound velocities then provide an important constraint on the amount and kind of light elements in the core. Although seismological observations provide density–sound velocity data of Earth’s core, there are few measurements in controlled laboratory conditions for comparison. We report the compressional sound velocity (VP) of hcp-Fe up to 163 GPa and 3000 K using inelastic x-ray scattering from a laser-heated sample in a diamond anvil cell. We propose a new high-temperature Birch’s law for hcp-Fe, which gives us the VP of pure hcp-Fe up to core conditions. We find that Earth’s inner core has a 4 to 5% smaller density and a 4 to 10% smaller VP than hcp-Fe. Our results demonstrate that components other than Fe in Earth’s core are required to explain Earth’s core density and velocity deficits compared to hcp-Fe. Assuming that the temperature effects on iron alloys are the same as those on hcp-Fe, we narrow down light elements in the inner core in terms of the velocity deficit. Hydrogen is a good candidate; thus, Earth’s core may be a hidden hydrogen reservoir. Silicon and sulfur are also possible candidates and could show good agreement with PREM if we consider the presence of some melt in the inner core, anelasticity, and/or a premelting effect.

The Earth's core and the phase diagram of iron

1982 ◽  
Vol 306 (1492) ◽  
pp. 21-35 ◽  
Keyword(s):  
Shock Wave ◽  
Phase Diagram ◽  
Inner Core ◽  
Temperature Drop ◽  
Melting Curve ◽  
Outer Core ◽  
Melting Point Depression ◽  
The Core ◽  
Wave Measurements ◽  
Thermally Driven

The phase diagram of iron is presented for P < 330 GPa. The melting curve is derived from Stevenson’s generalized form of Lindemann’s law, successfully connecting the low-pressure (5-20 GPa) measurements to the new shock-wave measurements of 250 GPa. The isothermal equation of state of e-iron (h.c.p.) and y-iron (f.c.c.), indicate that the inner core density is that of pure solid iron. The present experiments cannot distinguish between the e or y phase for the inner core, but preference is given to y-iron. From these constructions, it is concluded that the melting temperature of iron at the inner core - outer core boundary pressure, T (i.c.b.), is 5200-6600 K. A likely model of the outer core temperature is presented by taking 5800 K as the probable value of T (i.c.b.), and assuming a temperature drop of 1000 K due to chemically induced melting point depression. This yields 3620 K for the T of the core side of the core-mantle boundary (c.m.b.). This model results in a large AjT(D"), (700 K), at the c.m.b., but the shock-wave data also allow other models where A!T(D") is less. A numerical experiment reveals that the value for A T(D") of 700 K does not lead to distortion of the density profile. The (y-8-liquid) triple point is beyond the i.c.b. Thus, diluted y-iron in the liquid phase constitutes the outer core. The experiments support a thermally driven model of the geomagnetic dynamo, and further support a model of a slowly freezing inner core for the energy source.

scholarly journals Фазовый переход в цилиндрических изинговых нанопроволоках и нанотрубках: приближение теории молекулярного поля

2019 ◽  
Vol 61 (4) ◽  
pp. 694
Author(s):  
В.А. Танрывердиев ◽  
В.С. Тагиев ◽  
М.Н. Абдуллаев ◽  
Г.Г. Керимова
Keyword(s):  
Field Theory ◽  
Phase Diagram ◽  
Transition Temperature ◽  
Exchange Interaction ◽  
Critical Behavior ◽  
Exchange Coupling ◽  
Molecular Field ◽  
Physical Parameters ◽  
Surface Exchange ◽  
The Core

AbstractWithin the approximation of the molecular field theory, the critical behavior of cylindrical Ising nanowires and nanotubes is studied. The model considered in this work consists of ferromagnetic spins S _c situated in the core of the system and ferromagnetic spins S _s situated on the surface wall; they are interconnected by the exchange coupling J _1. The transition temperature T _c for such systems has been calculated as a function of exchange interaction parameters. The influence of the surface exchange interaction and surface coupling on the magnetodynamic behavior of the system have been studied. Some characteristic properties obtained on the phase diagram are related to the ratio of characteristic physical parameters on the surface and core of the abovementioned nanostructures.

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