Thermodynamic Regime Research Articles

Local structure, thermodynamics, and phase behavior of asymmetric particle mixtures: Comparison between integral equation theories and simulation.

We study the structural pair correlations, thermodynamics, and fluid-fluid demixing phase behavior of dense binary sphere mixtures as predicted by integral equation theories with diverse closure approximations. The focus is on mixtures with a large size asymmetry over a wide range of compositions and strengths of interparticle attractive interactions with an emphasis on the nonperturbative strong bridging or network forming regime. Quantitative comparisons with simulations are carried out. At high volume fractions of the larger species, we find that all studied closures are reasonably good. However, large quantitative or even qualitative discrepancies compared with simulations emerge when the large species is the volumetrically minority component, under both entropic depletion and strong enthalpic bridging conditions. Overall, we find that using the modified-Verlet (MV) closure approximation for all three correlation functions leads to good predictions for structure, phase behavior, and the equation-of-state, along with assuring pair correlation functions which are rigorously positive. This symmetric or "triple MV" approximation has the advantage that the same closure can be used for any size ratio in all thermodynamic state regimes, in contrast to asymmetric closures. The good accuracy of the triple MV closure for particle mixtures provides as basis for developing improved theoretical descriptions of polymer nanocomposites and will serve as a crucial input to microscopic theories of slow dynamics in glass and gel forming systems.

Thermodynamic Capacity of Quantum Processes.

Thermodynamics imposes restrictions on what state transformations are possible. In the macroscopic limit of asymptotically many independent copies of a state-as for instance in the case of an ideal gas-the possible transformations become reversible and are fully characterized by the free energy. In this Letter, we present a thermodynamic resource theory for quantum processes that also becomes reversible in the macroscopic limit, a property that is especially rare for a resource theory of quantum channels. We identify a unique single-letter and additive quantity, the thermodynamic capacity, that characterizes the "thermodynamic value" of a quantum channel, in the sense that the work required to simulate many repetitions of a quantum process employing many repetitions of another quantum process becomes equal to the difference of the respective thermodynamic capacities. On a technical level, we provide asymptotically optimal constructions of universal implementations of quantum processes. A challenging aspect of this construction is the apparent necessity to coherently combine thermal engines that would run in different thermodynamic regimes depending on the input state. Our results have applications in quantum Shannon theory by providing a generalized notion of quantum typical subspaces and by giving an operational interpretation to the entropy difference of a channel.

Dependence of Entropy Production Density on the Rate of Temperature Change in Linear Thermodynamics

Experimental thermograms obtained on samples of different shapes and sizes under spontaneous cooling, pulsed resistive heating, or laser surface heating of the solid phase of high-temperature metals are analyzed. It is shown that all the thermograms can be ascribed to a linear thermodynamic regime. A linear dependence of the entropy production density on the rate of variation of the temperature is found on analyzing the thermograms. This means that the rate of variation in the temperature can be regarded as an additional variable for the entropy production density in the linear regime and can be used for representing properties measured in a nonstationary thermal regime.

Generation and Parametrization of Mean Plasma Radiative Properties Databases for Astrophysics and Nuclear Fusion Applications

In plasmas found in nuclear fusion energy and astrophysics, radiative properties play a pivotal role and they are needed in radiation hydrodynamic simulations of these plasmas. However, their calculation is a very complex problem involving very long computational times. One of the solutions is to perform parametrizations of the plasma radiative properties as a function of the plasma conditions which leads to considerable reductions in computational costs. In this work, we present models to generate and parametrize radiative properties databases as a function of plasma conditions which are valid for any plasma thermodynamic regime.

Biologically inspired far-from-equilibrium materials

Abstract

Harmonic Analysis in Phase Space and Finite Weyl\u2013Heisenberg Ensembles

Weyl–Heisenberg ensembles are translation-invariant determinantal point processes on mathbb {R}^{2d} associated with the Schrödinger representation of the Heisenberg group, and include as examples the Ginibre ensemble and the polyanalytic ensembles, which model the higher Landau levels in physics. We introduce finite versions of the Weyl–Heisenberg ensembles and show that they behave analogously to the finite Ginibre ensembles. More specifically, guided by the observation that the Ginibre ensemble with N points is asymptotically close to the restriction of the infinite Ginibre ensemble to the disk of area N, we define finite WH ensembles as adequate finite approximations of the restriction of infinite WH ensembles to a given domain Omega . We provide a precise rate for the convergence of the corresponding one-point intensities to the indicator function of Omega , as Omega is dilated and the process is rescaled proportionally (thermodynamic regime). The construction and analysis rely neither on explicit formulas nor on the asymptotics for orthogonal polynomials, but rather on phase-space methods. Second, we apply our construction to study the pure finite Ginibre-type polyanalytic ensembles, which model finite particle systems in a single Landau level, and are defined in terms of complex Hermite polynomials. On a technical level, we show that finite WH ensembles provide an approximate model for finite polyanalytic Ginibre ensembles, and we quantify the corresponding deviation. By means of this asymptotic description, we derive estimates for the rate of convergence of the one-point intensity of polyanalytic Ginibre ensembles in the thermodynamic limit.

Strain-controlled shell morphology on quantum rods

Semiconductor heterostructure nanocrystals, especially with core/shell architectures, are important for numerous applications. Here we show that by decreasing the shell growth rate the morphology of ZnS shells on ZnSe quantum rods can be tuned from flat to islands-like, which decreases the interfacial strain energy. Further reduced growth speed, approaching the thermodynamic limit, leads to coherent shell growth forming unique helical-shell morphology. This reveals a template-free mechanism for induced chirality at the nanoscale. The helical morphology minimizes the sum of the strain and surface energy and maintains band gap emission due to its coherent core/shell interface without traps, unlike the other morphologies. Reaching the thermodynamic controlled growth regime for colloidal semiconductor core/shell nanocrystals thus offers morphologies with clear impact on their applicative potential.

Study on energy extraction assisted with quantum correlated coherence in bath

Based on a hybrid model of a single-mode microcavity system plus an ensemble of two-level atoms (TLAs), we investigate the effect of quantum correlated coherence (QCC) [Tan K C, <i>et al.</i> 2016 Phys. Rev. A 94, 022329] of bath on the dynamic behaviors of system. The dynamic equations of system for a general bath with QCC have been derived. With the help of the GHZ-like state with QCC and its reference state, the role of QCC as a thermodynamic resource has been clearly shown where QCC could be used to enhance the system's energy. Meanwhile, combining with the analytical and numerical simulation methods, the influences of effective temperature of <inline-formula><tex-math id="M3">\begin{document}$ GHZ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20181525_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20181525_M3.png"/></alternatives></inline-formula>-like bath and the coupling strength between the system and the bath on the energy effect of QCC have been studied. We find that the energy contribution of QCC to the cavity field relies not only on the effective temperature of bath but also on the coupling strength. That is completely different from the case of traditional thermal bath where the energy captured by the cavity from the bath only depends on the bath temperature, i.e., the thermal distribution of TLAs. Moreover, several interesting phenomena, in the paper, have been shown: 1) the higher of the effective temperature of bath, the larger of the cavity's energy extracted from the QCC of bath; 2) under the fixed effective temperature of bath, the smaller of the coupling strength the larger of the maximal extractable energy from QCC of bath; 3) there exists the trade-off between the cavity's energy and the capability of cavity capturing the energy of TLAs entering the cavity, i.e., the cavity's energy extracted from each TLA crossing the cavity always decreases as the energy of cavity increases; 4) the energy contribution of QCC of bath to cavity is beyond the one of the thermal distribution of TLAs in bath, and it could become more prominent when the coupling strength is taken the smaller value, which also means that in the case of weak coupling strength it is the QCC of bath not the thermal distribution of bath dominating the cavity's energy. Thus, the QCC of bath could be viewed as a kind of high quality thermodynamic resource. It has the potential applications in the design of a quantum engine with high output power or efficiency, and the enhancement of charging speed of quantum battery. Our investigation is beneficial to the further understanding of quantum coherence in quantum thermodynamic regime.

Monochromatic and mean radiative properties of astrophysical plasma mixtures in nonlocal thermodynamic equilibrium regime

Radiative‐hydrodynamics and radiative transfer simulations of astrophysical plasmas require the determination of radiative properties. However, most of the plasma radiative properties are calculated assuming the plasma in coronal equilibrium or local thermodynamic equilibrium regimes that is often not the case for many scenarios. In this work, we present nonlocal thermodynamic equilibrium calculations of radiative opacities of Fe and S and of an astrophysical plasma mixture for temperatures larger than 100 eV. We also analyze the departure from local thermodynamic equilibrium simulations.

Strong Law of Large Numbers for Betti Numbers in the Thermodynamic Regime

We establish the strong law of large numbers for Betti numbers of random \v{C}ech complexes built on $\mathbb R^N$-valued binomial point processes and related Poisson point processes in the thermodynamic regime. Here we consider both the case where the underlying distribution of the point processes is absolutely continuous with respect to the Lebesgue measure on $\mathbb R^N$ and the case where it is supported on a $C^1$ compact manifold of dimension strictly less than $N$. The strong law is proved under very mild assumption which only requires that the common probability density function belongs to $L^p$ spaces, for all $1\leq p < \infty$.

The effect of surface roughness on dynamic behaviour of the successive multiple droplets impacting onto aluminium hot surfaces

The effects of hot surface roughness on dynamic behaviour of multiple droplets impacting hot solid surfaces were investigated in this research. The test material is Aluminium 6061 with surface roughness variation of 0.08 μm, 0.18 μm and 0.52 μm. The surface temperatures were 100 °C, 120 °C and 140 °C. The droplet dynamics during the impact have been observed using high-speed video camera then the results were characterized by using image processing technique. It could be concluded that each temperature shows different thermodynamic impact regime. The results also reveal that at surface temperature lower than 140 °C, the increase of surface roughness leads the increase of spreading diameter. In contrast, the spreading factor decreases with the increasing of surface roughness at 140 °C due to incomplete wetting of droplet on the surface. Meanwhile, the maximum spreading factor is relatively independent to the change of surface roughness.

Radiative properties for astrophysical plasma mixtures in nonlocal thermodynamic equilibrium

Radiative properties play a pivotal role in astrophysical plasma flows and are needed in radiation-hydrodynamic simulations in order to understand their behavior and also to interpret the plasma emission spectra, which are valuable diagnostic tools. Radiative properties of astrophysical plasma mixtures have been commonly calculated for low-density optically thin plasmas assuming coronal equilibrium and for high density assuming local thermodynamic equilibrium. However, there are wide ranges of conditions in which these thermodynamic regimes are not achieved and the plasma is in the nonlocal thermodynamic equilibrium regime. In the present work, a study of the plasma radiative properties of oxygen and iron and an astrophysical plasma mixture in nonlocal thermodynamic steady-state equilibrium is carried out. The ranges of electron temperatures and densities considered are 1--1000 eV and ${10}^{11}\text{--}{10}^{20}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$, respectively. In the study, departures from coronal and local thermodynamic equilibria in terms of the density and temperature are also analyzed. Large differences in the radiative properties that can reach two orders of magnitude when the plasma is far from these thermodynamic regimes are obtained. These analyses are done assuming the plasma to be optically thin. A brief study of the influence of the plasma self-absorption in the radiative properties of oxygen and iron is made. For that purpose, the plasma is assumed with planar geometry and the study is performed in terms of the width of the plasma slab and electron temperature and density.

Solvation and Entropic Regimes in Ion-Containing Block Copolymers

The phase behavior of ion-containing block copolymers is studied using a field-theoretic model consisting of fully mobile ions immersed in a heterogeneous dielectric medium. Two distinct thermodynamic regimes are found to emerge, resulting from the competition between ion translational entropy and solvation free energy. In the regime dominated by entropy, the disordered phase is stabilized by the addition of ions. In the regime dominated by solvation free energy, the disordered phase is destabilized, leading to a “chimney”-like channel of stable ordered phases at sufficiently large ion concentrations. The two regimes are demarcated by the parameter λB, which quantifies the variation in solvation energy upon transferring ions between different dielectric domains. Estimates of λB for experimental systems suggest that the majority of block copolymer electrolytes fall within the solvation regime.

Coulomb log for conductivity of dense plasmas

The Coulomb log (log Λ) approximation is widely used to approximate electron transport coefficients in dense plasmas. It is a classical approximation to the momentum transport cross section. The accuracy of this approximation for electrical conductivity in dense plasmas is assessed by comparing to fully quantum mechanical calculations for realistic scattering potentials. It is found that the classical approximation is accurate to ±10% when log Λ &amp;gt; 3, irrespective of the plasma species. The thermodynamic regime (density and temperature) for which log Λ &amp;gt; 3 corresponds to does, however, strongly depend on the material. For increasing Z, log Λ is greater than 3 for increasingly high temperatures and lower densities.

Polar stratospheric cloud climatology based on CALIPSO spaceborne lidar measurements from 2006 to 2017

Abstract. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite has been observing polar stratospheric clouds (PSCs) from mid-June 2006 until the present. The spaceborne lidar profiles PSCs with unprecedented spatial (5 km horizontal×180 m vertical) resolution and its dual-polarization capability enables classification of PSCs according to composition. Nearly coincident Aura Microwave Limb Sounder (MLS) measurements of the primary PSC condensables (HNO3 and H2O) provide additional constraints on particle composition. A new CALIOP version 2 (v2) PSC detection and composition classification algorithm has been implemented that corrects known deficiencies in previous algorithms and includes additional refinements to improve composition discrimination. Major v2 enhancements include dynamic adjustment of composition boundaries to account for effects of denitrification and dehydration, explicit use of measurement uncertainties, addition of composition confidence indices, and retrieval of particulate backscatter, which enables simplified estimates of particulate surface area density (SAD) and volume density (VD). The over 11 years of CALIOP PSC observations in each v2 composition class conform to their expected thermodynamic existence regimes, which is consistent with previous analyses of data from 2006 to 2011 and underscores the robustness of the v2 composition discrimination approach. The v2 algorithm has been applied to the CALIOP dataset to produce a PSC reference data record spanning the 2006–2017 time period, which is the foundation for a new comprehensive, high-resolution climatology of PSC occurrence and composition for both the Antarctic and Arctic. Time series of daily-averaged, vortex-wide PSC areal coverage versus altitude illustrate that Antarctic PSC seasons are similar from year to year, with about 25 % relative standard deviation in Antarctic PSC spatial volume at the peak of the season in July and August. Multi-year average, monthly zonal mean cross sections depict the climatological patterns of Antarctic PSC occurrence in latitude–altitude and also equivalent-latitude–potential-temperature coordinate systems, with the latter system better capturing the microphysical processes controlling PSC existence. Polar maps of the multi-year mean geographical patterns in PSC occurrence frequency show a climatological maximum between longitudes 90∘ W and 0∘, which is the preferential region for forcing by orography and upper tropospheric anticyclones. The climatological mean distributions of particulate SAD and VD also show maxima in this region due to the large enhancements from the frequent ice clouds. Stronger wave activity in the Northern Hemisphere leads to a more disturbed Arctic polar vortex, whose evolution and lifetime vary significantly from year to year. Accordingly, Arctic PSC areal coverage is distinct from year to year with no “typical” year, and the relative standard deviation in Arctic PSC spatial volume is &gt;100 % throughout most of the season. When PSCs are present in the Arctic, they most likely occur between longitudes 60∘ W and 90∘ E, which is consistent with the preferential location of the Arctic vortex. Comparisons of CALIOP v2 and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) Antarctic PSC observations show excellent correspondence in the overall spatial and temporal evolution, as well as for different PSC composition classes. Climatological patterns of CALIOP v2 PSC occurrence frequency in the vicinity of McMurdo Station, Antarctica, and Ny-Ålesund, Spitsbergen, are similar in nature to those derived from local ground-based lidar measurements. To investigate the possibility of longer-term trends, appropriately subsampled and averaged CALIOP v2 PSC observations from 2006 to 2017 were compared with PSC data during the 1978–1989 period obtained by the spaceborne solar occultation instrument SAM II (Stratospheric Aerosol Measurement II). There was good consistency between the two instruments in column Antarctic PSC occurrence frequency, suggesting that there has been no long-term trend. There was less overall consistency between the Arctic records, but it is very likely due to the high degree of interannual variability in PSCs rather than a long-term trend.

Carbothermal Shock Synthesis of Multimetallic, Solid Solution Electrocatalysts for Air-Based Batteries

Multicomponent nanomaterials are extremely difficult to synthesize by conventional methods. Accordingly, nanoparticles composed of immiscible elemental combinations tend to phase-separate rather than form singe-phase solid solutions, which limits the compositional space. A synthetic technique that facilitates kinetic control over thermodynamic mixing regimes is therefore advantageous and offers untold scientific and technological opportunities. Here, we present a general route to alloy up to eight dissimilar elements into high entropy alloy nanoparticles (HEA-NPs) through a facile and tunable synthesis method: carbothermal shock (CTS).1 CTS employs flash heating and cooling of metal precursors on carbon to produce multimetallic nanoparticles with tailored elemental compositions, particle sizes, and structural complexity. Uniform mixing of nearly any metallic combination is achieved through high temperature exposure (~2000 K) during the thermal shock (55 ms) process, while rapid quenching (~105 K/s) retains this high-entropy state to form single-phase solid solutions. This new synthetic technique promotes materials discovery and design for a wide range of applications, including catalysis and energy storage. Inspired by the performance of quinary HEA-NPs as ammonia oxidation catalysts, novel solid solution nanoparticles (with 2 or more metallic elements) are synthesized and evaluated as electrocatalysts in air-based batteries, such as lithium-oxygen (Li-O2) and Li-CO2. In this way, HEA-NPs composed of catalytically active elements may impart synergistic electrocatalytic effects to improve overall battery performance. This talk will describe the process and underlying mechanism to synthesize HEA-NPs, the overall capabilities of the CTS method, and recent results on electrocatalyst development towards Li-air battery applications.

Electrochemical and Mechanical Driving Forces for Lithium Electrodeposition

It is well documented in the scientific literature that lithium electrodeposits grow into elongated "dendritic" structures from the top (tip-controlled) at high current densities and into mossy structures from the base (base-controlled) under low current densities [1,2]. In order to physically understand base-controlled growth, first an analytical model has been developed to incorporate the thermodynamic and kinetic driving forces of lithium to describe the multiphysical electrodeposition kinetics of lithium. Given the charging current density, the following regimes of lithium growth behavior are readily predicted from the analytical framework: (i) thermodynamic suppression regime, (ii) incubation regime, (iii) tip-controlled regime, (iv) base-controlled regime, and (v) mixed growth regime. These regimes explain the experimental observations and provide the kinetic boundaries between tip- and base-controlled growth [3]. Further, numerical calculations demonstrate that high von Mises stresses in localized regions of the lithium whisker extrude lithium and lead to base-controlled growth. In addition, the complex multiphysical dendrite-dendrite electro-chemo-mechanical interactions are rationalized through local electric fields, electrodeposition rates, mechanical stresses, and plastic velocities that are otherwise difficult to visualize in-situ in experiments. Overall, the combined analytical and the numerical frameworks provide multiphysical insight and serve as a design guideline for dendrite-free rechargeable batteries. [1] O. Crowther, A. C. West. “Effect of electrolyte composition on lithium dendrite growth.” Journal of the Electrochemical Society, 155, A806-A811 (2008). [2] P. Bai, J. Li, F.R. Brushett, M.Z. Bazant. “Transition of lithium growth mechanisms in liquid electrolytes.” Energy & Environmental Science, 9, 3221-3229 (2016). [3] A. Jana, R.E. García. “Lithium dendrite growth mechanisms in liquid electrolytes.” Nano Energy, 41, 552-565 (2017).

Influence of Particle Physical State on the Uptake of Medium-Sized Organic Molecules.

The uptake of medium-sized levoglucosan and 2,4-dinitrophenol to organic particles produced by α-pinene ozonolysis and to ammonium sulfate particles was studied from 10% to >95% relative humidity (RH). For aqueous sulfate particles, the water-normalized gas-particle partitioning coefficient of levoglucosan decreased from (1.0 ± 0.1) × 10-3 to (0.2 ± 0.1) × 10-3 (ng μg-1)particle/(ng m-3)gas from 40% to >95% RH, suggestive of a salting-in mechanism between levoglucosan and ionic ammonium sulfate solutions. For the organic particles, the levoglucosan partitioning coefficient increased from 10% to 40% RH and became invariant at (2.0 ± 0.4) × 10-3 (ng μg-1)/(ng m-3) above 40% RH. A kinetic limitation on uptake below 40% RH was implied, compared to a thermodynamic regime above 40% RH. The estimated diffusivity was 10-19±0.05 m2 s-1 at 40% RH. By comparison, the uptake of 2,4-dinitrophenol onto the organic particles was below detection limit, implying an upper limit on the partitioning coefficient of 6.8 × 10-6 (ng μg-1)/(ng m-3) at 80% RH. The results highlight that the molecular uptake of gases onto particles can be regulated by both kinetic and thermodynamic factors, either of which can limit the uptake of medium-sized organic molecules by atmospherically relevant particles.

Amino proton donors in excited-state intramolecular proton-transfer reactions

Proton transfer involving site-specific hydrogen-bonding interactions is one of the most fundamental and important reactions in chemistry and biology. Deliberately triggering this reaction by photoexcitation enables unique and insightful mechanistic analyses. This Review describes a particularly effective method that involves exciting a photoacid containing both an amine and a basic residue and monitoring the ensuing excited-state intramolecular proton-transfer (ESIPT) reactions. Replacing a H atom on the amine with another substituent R modulates the acidity of the amine and allows for the excited-state hydrogen-bond strength to be tuned over a very broad range. In this way, one can draw empirical correlations between N−H bond distances, acidity, hydrogen-bond strength and the ESIPT kinetics and thermodynamics. For example, stronger intramolecular N−H···N hydrogen bonding leads to faster and more exergonic ESIPT. Tuning the amine and basic residues allows one to switch the ESIPT mechanism between the kinetic and thermodynamic regimes, such that molecules can generate ratiometric emission, which is suitable for white-light generation and two-colour imaging. The identity of the amine substituent R not only affects the acidity but can be differentially sensitive towards the local chemical environment. Thus, the R group transduces environmental changes into modified ESIPT rates and/or mechanisms. Such studies open new frontiers in the fundamental aspects of proton transfer in amines, as well as their largely unexplored potential applications. This Review describes excited-state intramolecular proton-transfer (ESIPT) reactions with amines as proton donors. Systematic variation of N−H bond strength, acidity and reaction rate enables ESIPT kinetics and thermodynamics to be correlated and new molecules to be designed for sensing and optoelectronics applications.

Thermoacoustic sound projector: exceeding the fundamental efficiency of carbon nanotubes

The combination of smooth, continuous sound spectra produced by a sound source having no vibrating parts, a nanoscale thickness of a flexible active layer and the feasibility of creating large, conformal projectors provoke interest in thermoacoustic phenomena. However, at low frequencies, the sound pressure level (SPL) and the sound generation efficiency of an open carbon nanotube sheet (CNTS) is low. In addition, the nanoscale thickness of fragile heating elements, their high sensitivity to the environment and the high surface temperatures practical for thermoacoustic sound generation necessitate protective encapsulation of a freestanding CNTS in inert gases. Encapsulation provides the desired increase of sound pressure towards low frequencies. However, the protective enclosure restricts heat dissipation from the resistively heated CNTS and the interior of the encapsulated device. Here, the heat dissipation issue is addressed by short pulse excitations of the CNTS. An overall increase of energy conversion efficiency by more than four orders (from 10−5 to 0.1) and the SPL of 120 dB re 20 μPa @ 1 m in air and 170 dB re 1 μPa @ 1 m in water were demonstrated. The short pulse excitation provides a stable linear increase of output sound pressure with substantially increased input power density (>2.5 W cm−2). We provide an extensive experimental study of pulse excitations in different thermodynamic regimes for freestanding CNTSs with varying thermal inertias (single-walled and multiwalled with varying diameters and numbers of superimposed sheet layers) in vacuum and in air. The acoustical and geometrical parameters providing further enhancement of energy conversion efficiency are discussed.