Phase Diagram Boundaries Research Articles

Vibration Suppression of Two Adjacent Cables Using an Interconnected Tuned Mass Damper/Nonlinear Energy Sink

Due to their high flexibility, low damping, and small mass, stay cables are prone to large-amplitude vibrations. Various mechanical measures, typically installed near the cable anchorage to the deck, have been developed to suppress cable vibration. These dampers, however, may not be effective for ultralong cables since the damper is close to the cable anchorage, the cable node. In this paper, a tuned mass damper (TMD)/nonlinear energy sink (NES) are considered for installation between two adjacent stay cables for vibration mitigation. Firstly, the static equilibrium equation of the stay cable–damper system is established, and the influence of the self-weight of the damper on cable shape is investigated. The governing equations describing the motion of the two adjacent cables with a damper are then established using the Hamilton principle, which are then solved by the method of separation of variables. For cases of swept-sine excitation and harmonic excitation, the optimal designs of TMD and NES are achieved with the purpose of suppressing the first- and third-mode-dominated vibrations, respectively. Both optimal TMD and NES may substantially suppress cable vibrations, with each having advantages under certain situations. Finally, the dynamic response characteristics of two adjacent cables with an optimal damper are analyzed. Interesting dynamic behaviors, such as energy input suppression, phase shift, cable frequency shift, and phase diagram boundary rotation, are identified, and their mechanisms are explained.

Disorder-Broadened Phase Boundary with Enhanced Amorphous Superconductivity in Pressurized In2Te5.

As an empirical tool in materials science and engineering, the iconic phase diagram owes its robustness and practicality to the topological characteristics rooted in the celebrated Gibbs phase law free variables (F) = components (C) - phases (P) + 2. When crossing the phase diagram boundary, the structure transition occurs abruptly, bringing about an instantaneous change in physical properties and limited controllability on the boundaries (F = 1). Here, the sharp phase boundary is expanded to an amorphous transition region (F = 2) by partially disrupting the long-range translational symmetry, leading to a sequential crystalline-amorphous-crystalline (CAC) transition in a pressurized In2Te5 single crystal. Through detailed in situ synchrotron diffraction, it is elucidated that the phase transition stems from the rotation of immobile blocks [In2Te2]2+, linked by hinge-like [Te3]2- trimers. Remarkably, within the amorphous region, the amorphous phase demonstrates a notable 25% increase of the superconducting transition temperature (Tc), while the carrier concentration remains relatively constant. Furthermore, a theoretical framework is proposed revealing that the unconventional boost in amorphous superconductivity might be attributed to an intensified electron correlation, triggered by a disorder-augmented multifractal behavior. These findings underscore the potential of disorder and prompt further exploration of unforeseen phenomena on the phase boundaries.

Pseudogap in Sr2−xLaxIrO4: Gor'kov-Teitel'baum thermal activation model

Recently, Hall effect measurements are done on Lanthanum doped Strontium Iridate Sr2−xLaxIrO4 which is 5d analogue of cuprates [1]. Hall effect measurements show that the effective carrier density nH exhibits a crossover from nH∼x to nH∼1+x near x≃0.16. This is very similar to that found in cuprates around p≃0.19. It is proposed that a pseudogap (PG) state in Sr2−xLaxIrO4 exists and is ending at x≃0.16[1]. However, PG boundary (in doping-temperature phase diagram) remains unknown. In this work, we apply a very successfull the Gor'kov-Teitel'baum Thermal Activation (GTTA) model to Sr2−xLaxIrO4 and obtain its PG phase boundary and draw an updated phase diagram. Our results agree with previously known signatures of PG phase in this system [2–4]. Using results from GTTA model we also obtain the evolution of “Fermi arcs” in this system as a function temperature for doping concentration x≃0.08 which are in qualitative agreement with the reported results.

Kinetic effects during the plane-front and dendritic solidification of multicomponent alloys

A generalized model for the kinetics of a dendrite tip with a non-equilibrium interface is presented for multicomponent alloys. The model includes full coupling with thermodynamic databases to account for non-dilute non-ideal solutions, in addition to a full diffusion matrix in the liquid. The consequences of the computed non-equilibrium phase diagram boundaries on the dendrite tip kinetics are considered, and substantial deviations from existing theories are observed, especially in the case of zero solute drag. The model is applied to the rapid solidification of Inconel 718 (a nickel-based superalloy) and 316L (a stainless steel), which contain seven and five solute species, respectively. From the model, the phase diagram properties (i.e., partition coefficients and liquidus slopes) are able to be directly visualized as a function of velocity and observed to vary non-linearly and, in some cases, non-monotonically due to the combination of non-linear phase diagrams and kinetic effects. Finally, recent reports in the literature on the competition between the growth of ferrite and austenite from the melt in 316L are revisited with these new developments.

Impact of wettability on immiscible displacement in water saturated thin porous media

The characterization of immiscible displacement processes at the pore scale is crucial in order to understand macroscopic behaviors of fluids for efficient use of multiphase transport in various applications. In this study, the impact of porous material wetting properties on gas invasion behavior at various gas injection rates was investigated for thin hydrophilic porous media. An experimentally validated two-phase computational fluid dynamics model was employed to simulate the dynamic fluid–fluid displacement process of oxygen gas injection into liquid water saturated thin porous media. A phase diagram was developed through a parametric characterization of the thin porous media in terms of the material hydrophobicity and gas flow rates. In addition to calculating the saturation of the invading gas, gas pressure variations were calculated and used to identify the locations of phase diagram boundaries. Non-wetting phase streamlines resolved at the microscale were visualized and presented as a novel indicator for identifying displacement regimes and phase diagram boundaries. It was observed that the crossover from the capillary fingering regime to the stable displacement regime occurred between contact angles of 60° and 80°. By increasing the gas injection rate, due to viscous instabilities, flow patterns transitioned from the capillary fingering and stable displacement regimes to viscous fingering regime.

Tau liquid-liquid phase separation is modulated by the Ca2+ -switched chaperone activity of the S100B protein.

Aggregation of the microtubule-associated protein tau is implicated in several neurodegenerative tauopathies including Alzheimer's disease (AD). Recent studies evidenced tau liquid-liquid phase separation (LLPS) into droplets as an early event in tau pathogenesis with the potential to enhance aggregation. Tauopathies like AD are accompanied by sustained neuroinflammation and the release of alarmins at early stages of inflammatory responses encompass protective functions. The Ca2+ -binding S100B protein is an alarmin augmented in AD that was recently implicated as a proteostasis regulator acting as a chaperone-type protein, inhibiting aggregation and toxicity through interactions of amyloidogenic clients with a regulatory surface exposed upon Ca2+ -binding. Here we expand the regulatory functions of S100B over protein condensation phenomena by reporting its Ca2+ -dependent activity as a modulator of tau LLPS induced by crowding agents (PEG) and metal ions (Zn2+ ). We observe that apo S100B has a negligible effect on PEG-induced tau demixing but that Ca2+ -bound S100B prevents demixing, resulting in a shift of the phase diagram boundary to higher crowding concentrations. Also, while incubation with apo S100B does not compromise tau LLPS, addition of Ca2+ results in a sharp decrease in turbidity, indicating that interactions with S100B-Ca2+ promote transition of tau to the mixed phase. Further, electrophoretic analysis and FLIM-FRET studies revealed that S100B incorporates into tau liquid droplets, suggesting an important stabilizing and chaperoning role contributing to minimize toxic tau aggregates. Resorting to Alexa488-labeled tau we observed that S100B-Ca2+ reduces the formation of tau fluorescent droplets, without compromising liquid-like behavior and droplet fusion events. The Zn2+ -binding properties of S100B also contribute to regulate Zn2+ -promoted tau LLPS as droplets are decreased by Zn2+ buffering by S100B, in addition to the Ca2+ -triggered interactions with tau. Altogether this work uncovers the versatility of S100B as a proteostasis regulator acting on protein condensation phenomena of relevance across the neurodegeneration continuum.

A robust and efficient algorithm for vapor-liquid-equilibrium/liquid-liquid-equilibrium (VLE/LLE) phase boundary tracking

A novel phase-boundary tracking method is proposed to precisely capture the vapor-liquid/liquid-asphaltene and vapor-liquid/liquid-liquid two-phase boundaries in pressure-temperature and pressure-composition phase diagrams. The two-phase boundary determined by the proposed phase-boundary tracking method intersects the three-phase boundary at the apex of the three-phase region, which indicates the continuation of the three-phase region. The calculated two-phase boundaries also agree well with those documented in the literature.

Effect of Tm of blend components on the isothermal melt-crystallization process of PHB/PLLA blends investigated using spectroscopic imaging and DSC

The understanding of morphology and crystallization in biopolymer blends offers the ability to tune these properties for specific uses. In this study, the isothermal melt-crystallization process of poly (3-hydroxybutyrate) (PHB)/poly ( l -lactic acid) (PLLA) blends with different weight loadings and molecular weights was investigated using in-situ attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopic imaging and differential scanning calorimetry (DSC). When the isothermal crystallization temperature is constant, increasing the fraction of blend component with a lower T m results in the decreasing T m of both blend components, which is indicated in DSC thermograms. The reduced T m delays the crystallization of both blend components and then the restrained crystallization leads to a greater extent of phase separation, which is shown in ATR-FTIR spectroscopic images. Likewise, at a constant isothermal crystallization temperature, with the decreasing molecular weights of blend components, the miscibility of polymer blend should be enhanced because of the shift of the phase boundary in phase diagram to lower temperatures. However, the decreasing overall crystallization rate and the delay of crystallization indicated in the integrated absorbance profiles and the decreasing T m indicated in the DSC thermograms can be used to explain the greater extent of phase separation in the PHB/PLLA blend shown in the spectroscopic images. A phase diagram was prepared to show the effect of polymer molecular weight on the miscibility of PHB/PLLA blends. Thus, increasing the fraction of the blend component with a higher T m , choosing polymers with a higher molecular weight and decreasing the isothermal crystallization temperature have been demonstrated to be effective methods to promote the miscibility of upper critical solution temperature (UCST) crystallizable polymer blends. Moreover, it was concluded that in-situ ATR-FTIR spectroscopic imaging can be combined with integrated absorbance profiles and DSC thermograms to deepen the understanding of multicomponent polymer systems. • A phase diagram was prepared to show the effect of M w on the miscibility of PHB/PLLA blends. • Effective methods are found to promote the miscibility of UCST polymer blends during isothermal crystallization process. • Spectroscopic imaging can be combined with DSC thermograms to deepen the understanding of multicomponent polymer systems.

Kinetic origins of the metastable zone width in the manganese oxide Pourbaix diagram

The metastable zone width is the region on a phase diagram where a phase transformation is thermodynamically favored but kinetically hindered. Reaction conditions may need to be far beyond the Pourbaix phase diagram boundaries to initiate nucleation.

Measuring boundaries in phase diagrams of ternary systems using titration calorimetry

This paper demonstrates how isothermal titration microcalorimetry (ITC) can be used for the global construction of several kinds of phase diagrams for ternary systems at 298.15 K and atmospheric pressure. The solid-solid-liquid system of KCl-KNO3-H2O has not yet been studied using ITC, and thus, it is the main system discussed. It is clear that thermal effects associated with transformations in a system (appearance or disappearance of a phase) change with the composition of the system in ampoule. During titration, the solubility curves (including the liquid-liquid and solid-liquid equilibrium lines) in ternary systems can be detected as changes in the slope of the heat evolved vs time plot or in the slope of the observed heat vs solvent concentration plot. ITC is more precise and repeatable than the visual-cloud-point method. This isothermal and isobaric titration method can also provide additional information regarding the dissolution heat and the dilution heat. On the basis of the three experimental solubilities of KCl, KNO3, and KCl + KNO3 (co-saturated solution) in H2O, the other intermediate points on the solubility curve can be obtained based on the lever rule and the assumption of ideal solution, and these results agree well with the experimental values.

High‐pressure structural investigation on lead‐free piezoelectric 0.5Ba(Ti0.8Zr0.2)O3 ‐ 0.5(Ba0.7Ca0.3)TiO3

AbstractThe solid solution 0.5Ba(Ti0.8Zr0.2)O3 − 0.5(Ba0.7Ca0.3)T iO3 (BCZT) has become a promising member of the lead‐free piezoelectric materials because of its exceptionally high piezoelectric properties. In this study, we focus on studying pressure‐dependent Raman spectroscopy, powder x‐ray diffraction, and dielectric constant measurements on BCZT. The data show several structural transitions are present, where the system from ambient mixed phase (tetragonal P4mm + orthorhombic Amm2) transforms into single phase (P4mm) at 0.3 GPa, then converts into cubic phase (Pm3m) at 4.8 GPa followed by another possible structural re‐ordering around 10 GPa. Although there have been a lot of unanimity with the ambient crystallographic state of BCZT, our analysis justifies the presence of an intermediate orthorhombic phase in the Morphological Phase Boundary (MPB) of BCZT phase diagram. The transformation tetragonal to cubic is indicated by the Raman mode softening, unit cell volume change, and the (Ti/Zr)O6 octahedra distortion, which coincides with the well‐known ferroelectric‐paraelectric transition of the system. The sudden drop in the dielectric constant value at 4.7 GPa also confirms the loss of ferroelectric nature of the BCZT ceramic.

Theoretical phase diagram of boron carbide from ambient to high pressure and temperature

The phase diagram of boron carbide is calculated within the density functional theory as a function of temperature and pressure up to 80 GPa, accounting for icosahedral, graphitelike, and diamondlike atomic structures. Only some icosahedral phases turn out to be thermodynamically stable with atomic carbon concentrations (c) of 8.7% (B10.5C), 13.0% (B6.7C), 20% (B4C), and 28.6% (B2.5C), respectively. Their respective ranges of stability under pressure and temperature are calculated, and the theoretical T-P-c phase diagram boundaries are discussed. At ambient conditions, the introduction in the phase diagram of the new phase B10.5C with an ordered crystalline motif of 414 atoms is shown to bring the theoretical solubility range of carbon in boron close to the experimental one. The link with the experimental phase diagram consisting of one single phase having the R3¯m space group is discussed, and the concept of partial occupation of Wyckoff’s site is introduced. At high pressure, the phase diagram is defined by a new carbon-rich phase B2.5C, which is stabilized by both pressure and temperature in our calculations. All of the other diamond and graphite phases reported previously turn out to be thermodynamically unstable in our calculations, although some of them are observed in high pressure experiments.

Chiral phase transition with 2+1 quark flavors in an improved soft-wall AdS/QCD model

We study the chiral phase transition with 2 + 1 quark flavors in an improved soft-wall AdS/QCD model, which can produce the light meson spectrum and many other low-energy quantities consistent with experiments in the two-flavor case. The chiral transition behaviors of the quark condensates at different quark masses are analysed in detail, and the (m_{u,d}, m_s) phase diagram for the quark sector has been obtained from the improved soft-wall model. We find that the features of the calculated phase diagram are completely consistent with the standard scenario, which is supported by lattice simulations and theoretical arguments. The evidence of a tricritical point on the m_{u,d} = 0 boundary of the (m_{u,d}, m_s) phase diagram is first clearly presented in the bottom-up AdS/QCD.

Effects of LiNbO3 doping on the microstructures and electrical properties of BiScO3–PbTiO3 piezoelectric system

Piezoelectric ceramics xLiNbO3–yBiScO3–(1−x−y)PbTiO3 (LN–BS–PT, 0.00 ≤ x ≤ 0.10, 0.30 ≤ y ≤ 0.36) were synthesized and their phase diagram and morphotropic phase boundary between rhombohedral and tetragonal phases have been confirmed. The optimal properties were found at the composition of 0.03LN–0.36BS–0.61PT with piezoelectric coefficient d33* value of 702 pm/V, d33 of 551 pC/N, planar electromechanical coupling factor kp of 0.51, remnant polarization Pr of 46.5 µC/cm2, Curie temperature Tc of 337 °C, and a large strain of 0.351% at an electric field of 50 kV/cm and frequency of 2 Hz with a low strain hysteresis of 5.9%. The Curie temperature of the ternary system presents a linear relationship with LiNbO3 and BiScO3 contents. The optimization of these electric properties was probably ascribed to the enhancement in domain walls and the improving mobility of domain switching due to LiNbO3 doping.

Two-stage kinetic phase transition in a platelet–colloid mixture

The semi-grand canonical ensemble theory augmented by the free volume approximation and the scaled particle theory was applied to construct the Helmholtz free energy density function f of a mixture of uncharged colloidal hard spheres and a depletion agent of colloidal hard platelets. The episode of the phase-separation phenomenon is then described by a composite fm which is written as a sum of the coexisting free energy densities fi (i = gas, liquid or solid) and the latter is weighted by Vi/V, Vi and V being the ith spatial volume and total volume, respectively. In this work, we applied the free energy density minimization method to fm [16] and calculated the domains of phases in coexistence instead of delineating coexisting phase-diagram boundaries obtained by computing the pressure and chemical potential in the conventional thermodynamic equilibrium condition. The calculated coexistence domains thus have the same patterns as many colloidal laboratory experiments. We obtained in our calculated platelet–colloid phase diagram the well-known triangular area of triple-phases coexistence. This area, however, has to be realized as some kind of a kinetic process showing coalescence of two sets of coexisting biphases whenever any set of initial input number concentrations of platelets and colloids that falls inside this triangular area. In this kinetic phase-transition process, we find the triple phases of the platelet–colloid system always residing at the same three vertices of the triangle, but their spatial volumes are generally different depending on the initial number concentrations of platelets and colloids. It would be interesting and, a challenge as well, if laboratory experiments at the same quantitative level as that previously reported for the polymer–colloidal mixtures [7] can be carried out to confirm our theoretical findings.

The Influence of Hydrostatic Pressure and Electric Field to the Remanent Polarization of PbLa(Zr,Sn,Ti)O<sub>3</sub> Ceramic

Chemical composition Pb0.97La0.02(Zr0.75Sn0.136Ti0.114)O3 (PLZST) ceramic was fabricated by conventional solid-state reaction of oxide method. The composition is close to the AFE/FE phase boundary of PLZST ceramic phase diagram. The dependence of remanent polarization of Pb (Zr,Sn,Ti)O3 ceramic poled under different electric fields on hydrostatic pressure was investigated with special hydrostatic pressure equipment. The results show that PLZST ceramic poled at different DC electric field is metastable state ferroelectric phase. The remanent polarization decreases sharply and is depolarization completely when hydrostatic pressure increases to a bound.

Thermodynamics of Criticality: Percolation Loci, Mesophases and a Critical Dividing Line in Binary-Liquid and Liquid-Gas Equilibria

High-temperature and pressure boundaries of the liquid and gas states have not been defined thermodynamically. Standard liquid-state physics texts use either critical isotherms or isobars as ad hoc boundaries in phase diagrams. Here we report that percolation transition loci can define liquid and gas states, extending from super-critical temperatures or pressures to “ideal gas” states. Using computational methodology described previously we present results for the thermodynamic states at which clusters of excluded volume (VE) and pockets of available volume (VA), for a spherical molecule diameter σ, percolate the whole volume (V = VE + VA) of the ideal gas. The molecular-reduced temperature (T)/pressure(p) ratios ( ) for the percolation transitions are = 1.495 ± 0.015 and = 1.100 ± 0.015. Further MD computations of percolation loci, for the Widom-Rowlinson (W-R) model of a partially miscible binary liquid (A-B), show the connection between the ideal gas percolation transitions and the 1st-order phase-separation transition. A phase diagram for the penetrable cohesive sphere (PCS) model of a one-component liquid-gas is then obtained by analytic transcription of the W-R model thermodynamic properties. The PCS percolation loci extend from a critical coexistence of gas plus liquid to the low-density limit ideal gas. Extended percolation loci for argon, determined from literature equation-of-state measurements exhibit similar phenomena. When percolation loci define phase bounds, the liquid phase spans the whole density range, whereas the gas phase is confined by its percolation boundary within an area of low T and p on the density surface. This is contrary to a general perception and opens a debate on the definitions of gaseous and liquid states.

Percolation Transitions of the Ideal Gas and Supercritical Mesophase

High-temperature and pressure boundaries of the liquid and gaseous states have not been defined thermodynamically. Standard liquid-state physics texts use either critical isotherms or isobars as ad hoc boundaries in phase diagrams. Here we report that percolation transition loci can define liquid and gas states, extending from super-critical temperatures or pressures to “ideal gas” states. Using computational methodology described previously we present results for the thermodynamic states at which clusters of excluded volume (VE) and pockets of available volume (VA), for a spherical molecule diameter σ, percolate the whole volume (V = VE VA) of the ideal gas. The molecular-reduced temperature (T)/pressure (p) ratios (T* = kBT/pσ3) for the percolation transitions are T*PE = 1.495 ± 0.01 and T*PA = 1.100 ± 0.01. Further MD computations of percolation loci for the Widom-Rowlinson (W-R) model of a partially miscible binary liquid (A-B) show the connection between the ideal gas percolation transitions and the 1st-order phase-separation transition. A phase diagram for the penetrable cohesive sphere (PCS) model of a one-component liquid-gas is then obtained by analytic transcription of the W-R model thermodynamic properties. The PCS percolation loci extend from a critical coexistence of gas plus liquid to the low-density limit ideal gas. Extended percolation loci for argon, determined from literature equation-of-state measurements exhibit similar phenomena. When percolation loci define phase bounds, the liquid phase spans the whole density range, whereas the gas phase is confined by its percolation boundary within an area of low T and p on the density surface. This is contrary to a general perception, and reopens a debate of “what is liquid”. We append this contribution to the science of liquid-gas criticality and liquid-state bounds with further open debate.

Phase diagrams of diblock copolymers in electric fields: a self-consistent field theory study.

We investigated the phase diagrams of diblock copolymers in external electrostatic fields by using real-space self-consistent field theory. The lamella, cylinder, sphere, and ellipsoid structures were observed and analyzed by their segment distributions, which were arranged to two types of phase diagrams to examine the phase behavior in weak and strong electric fields. One type was constructed on the basis of Flory-Huggins interaction parameter and volume fraction. We identified an ellipsoid structure with a body-centered cuboid arrangement as a stable phase and discussed the shift of phase boundaries in the electric fields. The other type of phase diagrams was established on the basis of the dielectric constants of two blocks in the electric fields. We then determined the regions of ellipsoid phase in the phase diagrams to examine the influence of dielectric constants on the phase transition between ellipsoidal and hexagonally packed cylinder phases. A general agreement was obtained by comparing our results with those described in previous experimental and theoretical studies.

Neutron diffraction investigation of theH−Tphase diagram above the longitudinal incommensurate phase ofBaCo2V2O8

The quasi-one-dimensional antiferromagnetic Ising-like compound BaCo2V2O8 has been shown to be describable by the Tomonaga-Luttinger liquid theory in its gapless phase induced by a magnetic field applied along the Ising axis. Above 3.9 T, this leads to an exotic field-induced low-temperature magnetic order, made of a longitudinal incommensurate spin-density wave, stabilized by weak interchain interactions. By single-crystal neutron diffraction we explore the destabilization of this phase at a higher magnetic field. We evidence a transition at around 8.5 T towards a more conventional magnetic structure with antiferromagnetic components in the plane perpendicular to the magnetic field. The phase diagram boundaries and the nature of this second field-induced phase are discussed with respect to previous results obtained by means of nuclear magnetic resonance and electron spin resonance, and in the framework of the simple model based on the Tomonaga-Luttinger liquid theory, which obviously has to be refined in this complex system.