1,721,003 research outputs found
Pressure-driven relaxation processes in nanocomposite ionic glass LiFe0.75V0.10PO4
No full textThe result of Broadband Dielectric Spectroscopy measurements of vanadium doped lithium phosphoolivine based glass (LiV0.10Fe0.75PO4) after High-Presure (up to 2GPa) High-Temperature treatment and control sample measurements.All files provided are in ASCII text with tab separated columns and header lines.The names of the individual files correspond to the numbering of the figures in the paper: Szymon Starzonek, Aleksander Szpakiewicz-Szatan, Sylwester J. Rzoska, Aleksandra Drozd-Rzoska, Michał Boćkowski, Tomasz K. Pietrzak, Jerzy E. Garbarczyk, Pressure-driven relaxation processes in nanocomposite ionic glass LiFe0.75V0.10PO4, Journal of Non-Crystalline Solids, Volume 605, 2023, 122163, ISSN 0022-3093, https://doi.org/10.1016/j.jnoncrysol.2023.122163.Files included in collection:Fig1.dat - Thermal Analysis scans in tested Bi2O3 systems, from atmospheric pressure to P = 1GPa.Fig2.dat - DTA measurement of Bi2O3 based glass at ambient pressure (first two columns). XRD structure-related diagrams for the tested Bi2O3 based samples measured at selected temperatures and at at ambient pressure (in publication shown as insets in figure).Fig3.dat - XRD structures measured at ambient pressure and room temperature of materials after High-Pressure-High-Temperature treatment at selected pressures.Fig4.dat - Temperatures of observed phase transitions at various pressures.</p
The Discontinuity of the Isotropic — Masophase Transition in N-Cyanobiphenyls Homologous Series from 4CB to 14CB. Nonlinear Dielectric Effect (NDE) Studies
No full textPressure-Related Universal Previtreous Behavior of the Structural Relaxation Time and Apparent Fragility
Get PDFThe report presents the evidence for the hypothetically “universal” previtreous behavior of the pressure related apparent fragility: mT(P)∞1/(P*-P), where P* is the extrapolated singular pressure. This finding was the basis for deriving the “model-free” dependence for the pressure evolution of the structural relaxation time: τ(P)=τoP(P*-P)-Ψ. All these led to the new way of testing the dynamic crossover phenomenon via 1/mT (P) vs. P plot. Finally, the behavior of electric conductivity in the previtreous domain is discussed. The experimental evidence covers 8*OCB (liquid crystal), EPON 828 (resin), diisobutyl phthalate, and propylene carbonate (low molecular weight liquids). Experiments were carried up to extreme P~ 2.2 GPa, in the “bulk” measurement capacitor. This report also contains a summary of existing descriptions of the pressure evolution of structural relaxation time or viscosity on approaching the glass transition
Glassy dynamics of liquid crystalline 4′-n-pentyl-4-cyanobiphenyl in the isotropic and supercooled nematic phases
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‘Quasi-Tricritical’ and Glassy Dielectric Properties of a Nematic Liquid Crystalline Material
No full textResults of dielectric studies in the nematic and isotropic liquid phases of pentylcyanobiphenyl (5CB), a model rod-like liquid crystalline material, are shown. They are based on the discussion of the evolution of dielectric constant ( ε ), its changes under the strong electric field (nonlinear dielectric effect, NDE), and finally, the primary relaxation time. It is shown that changes in ε T and NDE are entirely dominated by the impact of pretransitional fluctuations (pre-nematic and pre-isotropic, respectively) which are associated with the weakly discontinuous character of the isotropic–nematic phase transition. This influence also extends for the low-frequency, ionic species dominated, region. Notable, that the derivative-based and distortions sensitive analysis revealed the tricritical nature of the I-N transition. Although the glass transition in 5CB occurs in the deeply supercooled state at T g ≈ − 68 ° C , the dynamics (changes of the primary relaxation time) follow a previtreous pattern both in the isotropic and in the nematic phase. Finally, the discussion of the ’molecular’ vs. ‘quasi-critical’ characterizations of the isotropic and nematic phases is presented. It shows the evident prevalence of the ‘quasi-critical-picture’, which offers the consistent temperature parameterization in the total tested temperature range
Shear viscosity studies above and below the critical consolute point in a nitrobenzene-decane mixture
No full textVerhulst-type equation and the universal pattern for global population growth.
No full textThe global population [Formula: see text] (growth from 10,000 BCE to 2023) is discussed in frames of the Verhulst-type scaling, recalling the sustainable development concept. The analysis focuses on the per capita global population growth rate, for which the analytic counterpart is considered:[Formula: see text]. The focused insight reveals two near- linear domains for [Formula: see text] changes: from ~ 700 CE till ~1968 and from ~1968 till 2023. It can be considered a reference pattern for long-term global population changes. For models recalling the Verhulst-type scaling, such analysis indicates that a single pair of growth rate and system resource coefficients [Formula: see text] should describe the rise in the global population. However, the Verhulst relation with such effective parameters does not describe [Formula: see text] changes, which raises the question of whether it is adequate to describe global population changes. Notably is the new way of data preparation, based on their collections from various sources and numerical filtering to obtain a 'smooth' optimal set. The changes of [Formula: see text] were analyzed via the 'reversed protocol' analysis, in comparison to the standard pattern, namely: (i) first, the linearized, distortions-sensitive transformation of [Formula: see text] data is carried out; it indicates domains where the validated application of a given scaling equation is possible and yields optimal values of relevant parameters, (ii) the final fitting via the selected scaling equation is carried out for identified domains, and using obtained optimal values of parameters. The analysis reveals links between [Formula: see text] local 'disturbations' and some historical and prehistorical reference events, showing their global scale impacts
On the Tricritical Point of the Isotropic — Nematic Transition in a Rod-Like Mesogen Hidden in the Negative Pressure Region
No full textAnomalous Decoupling of the dc Conductivity and the Structural Relaxation Time in the Isotropic Phase of a Rod-Like Liquid Crystalline Compound
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