An Unpublished Tasso Sonnet

Williamson, Edward

doi:10.2307/2909637

Cited by 3 publications

(4 citation statements)

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“…Note that this phase diagram has a second triple point associated with the disappearance of the cluster crystal phase, as well as the usual one associated with the disappearance of the liquid phase. We have not attempted to consider the effect of other possible phases on the phase diagram, such as the lamellar phase observed for Janus particles 33,37 and the two-dimensional crystalline lamellae 63 seen in simulations of octahedron-forming patchy particles. 32 Secondly, there are also a series of approximations associated with our description of the fluid.…”

Section: Discussionmentioning

confidence: 99%

Re-entrant phase behavior for systems with competition between phase separation and self-assembly

Reinhardt

Williamson

Doye

et al. 2011

The Journal of Chemical Physics

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In patchy particle systems where there is a competition between the self-assembly of finite clusters and liquid-vapor phase separation, re-entrant phase behavior can be observed, with the system passing from a monomeric vapor phase to a region of liquid-vapor phase coexistence and then to a vapor phase of clusters as the temperature is decreased at constant density. Here, we present a classical statistical mechanical approach to the determination of the complete phase diagram of such a system. We model the system as a van der Waals fluid, but one where the monomers can assemble into monodisperse clusters that have no attractive interactions with any of the other species. The resulting phase diagrams show a clear region of re-entrance. However, for the most physically reasonable parameter values of the model, this behavior is restricted to a certain range of density, with phase separation still persisting at high densities.

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Section: Discussionmentioning

confidence: 99%

Re-entrant phase behavior for systems with competition between phase separation and self-assembly

Reinhardt

Williamson

Doye

et al. 2011

The Journal of Chemical Physics

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“…We consider InAs spherical nanocrystals of diameter D = 30.3 and 42.2 Å. The surface dangling bonds are passivated using a large-gap barrier material [19]. Our analysis of the envelope functions extracted for the pseudopotential wave functions shows that the first electron level (e1) is predominantly s-like, while the next 3 electron levels (e2, e3, and e4) are predominantly p-like.…”

mentioning

confidence: 99%

“…The pseudopotential of the quantum dot V ps (r) is obtained from the superposition of screened atomic potentials, which are fitted [19] to reproduce the bulk experimental optical transition energies and effective masses, as well as the surface work function. Spin-orbit coupling is fully included in the solution of the Schroedinger equation.…”

mentioning

confidence: 99%

Addition Spectra of Quantum Dots: the Role of Dielectric Mismatch

2000

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Using atomistic pseudopotential wave functions we calculate the electron and hole charging energies of InAs quantum dots. We find that the charging energies depend strongly on the dielectric constant ǫ out of the surrounding material, and that when the latter is smaller than the dielectric constant of the dot (weak external screening) the electron-electron and hole-hole interactions are dominated by surface polarization effects. We predict the addition energies and the quasi-particle gap as a function of size and ǫ out . We find excellent agreement with recent single-dot tunneling spectroscopy data for ǫ out = 6.

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“…Other process variables that have been demonstrated to contain process information are arc plasma temperature as determined by atomic emission spectroscopy [9], magnetic field distribution around the crucible in the water jacket and outside the furnace [10], arc light emission intensity [11], ion distributions in the arc as determined by monochromatic imaging of the arc [12], and temperature, voltage and current distributions in the crucible [13]. Though of importance in specific applications designed to diagnose and investigate the VAR process, these variables are not currently used on a routine basis for practical reasons and are not represented in the process estimator described below.…”

Section: Important Var Process Variablesmentioning

confidence: 99%

Advancing Alloy 718 Vacuum Arc Remelting Technology Through Developing Model-Based Controls

Williamson

Beaman

Zanner³

et al. 2005

Superalloys 718, 625, 706 and Various Derivatives (2005)

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The Specialty Metals Processing Consortium (SMPC) was established in 1990 with the goal of advancing the technology of melting and remelting nickel and titanium alloys. In recent years, the SMPC technical program has focused on developing technology to improve control over the final ingot remelting and solidification processes to alleviate conditions that lead to the formation of inclusions and positive and negative segregation. A primary objective is the development of advanced monitoring and control techniques for application to vacuum arc remelting (VAR), with special emphasis on VAR of Alloy 718. This has lead to the development of an accurate, low order electrode melting model for this alloy as well as an advanced process estimator that provides real-time estimates of important process variables such as electrode temperature distribution, instantaneous melt rate, process efficiency, fill ratio, and voltage bias. This, in turn, has enabled the development and industrial application of advanced VAR process monitoring and control systems. The technology is based on the simple idea that the set of variables describing the state of the process must be self-consistent as required by the dynamic process model. The output of the process estimator comprises the statistically optimal estimate of this self-consistent set. Process upsets such as those associated with glows and cracked electrodes are easily identified using estimator based methods.

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An Unpublished Tasso Sonnet

Cited by 3 publications

References 0 publications

Re-entrant phase behavior for systems with competition between phase separation and self-assembly

Re-entrant phase behavior for systems with competition between phase separation and self-assembly

Addition Spectra of Quantum Dots: the Role of Dielectric Mismatch

Advancing Alloy 718 Vacuum Arc Remelting Technology Through Developing Model-Based Controls

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