What is spinodal decomposition?

Favvas, Evangelos P.; Mitropoulos, A.Ch.

doi:10.25103/jestr.011.05

Cited by 89 publications

(88 citation statements)

References 3 publications

(2 reference statements)

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“…For example, a liquid heated at constant pressure from a temperature on the left-hand side of the curve Sp(L) in Figure 16a, toward a temperature on the right-hand side of Sp (L), would undergo a sudden and violent spinodal decomposition back to a more stable biphasic liquid-gas mixture upon intersection of Sp(L) [e.g., Reid, 1978aReid, , 1978bReid, , 1978cFavvas and Mitropoulos, 2008;Thiéry and Mercury, 2009a]. Spinodal decomposition is a spontaneous and explosive phase separation that occurs throughout the fluid [e.g., Favvas and Mitropoulos, 2008;Thiéry and Mercury, 2009a]. Phase changes from metastable or unstable states back to more stable states of water in a hydrothermal crack represent a promising source mechanism for both LPs and subevents at MSH.…”

Section: Lps During the 8 March 2005 Phreatic Explosionmentioning

confidence: 99%

Subevents of long‐period seismicity: Implications for hydrothermal dynamics during the 2004–2008 eruption of Mount St. Helens

Matoza

Chouet

2010

J. Geophys. Res.

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[1] One of the most striking aspects of seismicity during the 2004-2008 eruption of Mount St. Helens (MSH) was the precise regularity in occurrence of repetitive long-period (LP) or "drumbeat" events over sustained time periods. However, this precise regularity was not always observed, and at times the temporal occurrence of LP events became more random. In addition, accompanying the dominant LP class of events during the 2004-2008 MSH eruption, there was a near-continuous, randomly occurring series of smaller seismic events. These subevents are not always simply small-amplitude versions of the dominant LP class of events but appear instead to result from a separate random process only loosely coupled to the main LP source mechanism. We present an analysis of the interevent time and amplitude distributions of the subevents, using waveform cross correlation to separate LP events from the subevents. We also discuss seismic tremor that accompanied the 8 March 2005 phreatic explosion event at MSH. This tremor consists of a rapid succession of LPs and subevents triggered during the explosion, in addition to broadband noise from the sustained degassing. Immediately afterward, seismicity returned to the pre-explosion occurrence pattern. This triggering in relation to the rapid ejection of steam from the system, and subsequent return to pre-explosion seismicity, suggests that both seismic event types originated in a region of the subsurface hydrothermal system that was (1) in contact with the reservoir feeding the 8 March 2005 phreatic explosion but (2) not destroyed or drained by the explosion event. Finally, we discuss possible thermodynamic conditions in a pressurized hydrothermal crack that could give rise to seismicity. Pressure drop estimates for typical LP events are not generally large enough to perturb pure water in a shallow hydrothermal crack into an unstable state. However, dissolved volatiles such as CO 2 may lead to a more unstable system, increasing the seismogenic potential of a hydrothermal crack subject to rapid heat flux. The interaction of hydrothermal and magmatic systems beneath MSH in 2004-2008 thus appears able to explain a wide range of observed phenomena, including subevents, LP events, larger (M d > 2) events, and phreatic explosions.

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Section: Lps During the 8 March 2005 Phreatic Explosionmentioning

confidence: 99%

Subevents of long‐period seismicity: Implications for hydrothermal dynamics during the 2004–2008 eruption of Mount St. Helens

Matoza

Chouet

2010

J. Geophys. Res.

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“…In this figure, phase separation is observed, as regions in which a precipitate of Ti nanocrystals with sizes between approximately 10 and 20 nm in an amorphous matrix of WS 2 can be identified. This phenomenon is attributed to the supersaturation of Ti, and it is known as spinodal decomposition [27,28]. T. W. Scharf et al [8] have deposited WS 2 films doped with Ti using the magnetron co-sputtering technique; in this work, a Ti concentration of approximately 7% was found, accompanied by the observation of a formation of Ti crystals in an amorphous matrix of WS 2 .…”

Section: Transmission Electron Microscopy (Tem)mentioning

confidence: 87%

Structure and Properties of Titanium Doped Tungsten Disulfide Thin Films Produced via the Magnetron Co-Sputtering DC Technique

Carmona

Sequeda

2016

Matéria (Rio J.)

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In this work, titanium doped tungsten disulfide thin films (WS 2 -Ti) were deposited on AISI 304 stainlesssteel substrates using the magnetron co-sputtering DC technique. Films were produced with varying titaniumcathode power from 0 to 25 W. The titanium content of the WS 2 structure was determined using energy dispersive spectroscopy (EDS), thereby obtaining a maximum of 10% for the sample grown at 25 W. X-ray diffraction (XRD) results indicated, for the pure sample, the presence of a hexagonal phase of high intensity on the (103) plane. However, with the addition of titanium, the WS 2 crystallinity was reduced; nevertheless, when the titanium content was equal to 10%, nanocomposite formation was promoted. This effect was observed in TEM (transmission electron microscopy) images. Finally, the tribological behavior was determined using a ball on disk (BOD) test. With this method, friction coefficient curves were obtained with respect to the number of cycles, allowing the measurement of friction coefficient values of 0.1 for the pure sample and 0.15 for the sample grown at 5 W. Because of the low thickness of the samples, all of them failed during the first cycles.

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“…When the composition of the homogenous alloy is between the spinodals and the solubility limits R crit becomes large. In this region, a positive ⌬F requires a large concentration fluctuation 39 which, according to Figs. 2 and 3, corresponds to large ␥ and thus to large R crit .…”

Section: Critical Nucleus Sizementioning

confidence: 93%

First-principles determination of theα−α′interfacial energy in Fe-Cr alloys

Yang

et al. 2010

Phys. Rev. B

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The interfacial energies ͑␥͒ between the Cr-rich ␣Ј-Fe x Cr 1−x and Fe-rich ␣-Fe 1−y Cr y phases ͑0 Ͻ x , y Ͻ 0.35͒ are calculated to be between ϳ0.02 and ϳ0.33 J m −2 for the ferromagnetic state and between ϳ0.02 and ϳ0.27 J m −2 for the paramagnetic state. Although for both magnetic states, the interfacial energy follows a general decreasing trend with increasing x and y, the fine structures of the ␥͑x , y͒ maps exhibit a marked magnetic state dependence. The subtleties are shown to be ascribed to the magnetic interaction between the Fe and Cr atoms near the interface. The theoretical results are applied to estimate the critical grain size for nucleation and growth in Fe-Cr stainless steel alloys.

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What is spinodal decomposition?

Cited by 89 publications

References 3 publications

Subevents of long‐period seismicity: Implications for hydrothermal dynamics during the 2004–2008 eruption of Mount St. Helens

Subevents of long‐period seismicity: Implications for hydrothermal dynamics during the 2004–2008 eruption of Mount St. Helens

Structure and Properties of Titanium Doped Tungsten Disulfide Thin Films Produced via the Magnetron Co-Sputtering DC Technique

First-principles determination of theα−α′interfacial energy in Fe-Cr alloys

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