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International audience; An important category of glass-forming materials is organic; it includes molecular liquids, polymers, solutions, proteins that can be vitrified by cooling the liquid under standard conditions or after special thermal treatments. The range of applications is large from materials to life sciences and recently to electronics. To distinguish them from other systems described in this issue, some specific properties such as the range of their glass transition temperature ($T_g$), their ability to vitrify and some rules of thumb to locate $T_g$ are presented. The most remarkable property of these liquids is how fast in temperature their viscosity or structural relaxation time increases as approaching $T_g$. To characterize this behavior and rank the liquids of different strength, C.A. Angell introduced the concept of Fragility nearly 40 years ago. He proposed to classify liquids as fragile or strong in an Arrhenius plot with $T_g$ scaling (the strongest ones have never being observed in organic glasses, except for water under specific conditions). The $T_g$ value and the fragility of a given liquid can be changed by applying pressure, i.e. changing the density. One can then explore the properties of the supercooled/overcompressed liquid and the glass in a $P − T$ phase diagram. The $T_g$ line corresponds to an isochronic line, i.e. a line at constant relaxation time with different pairs of density-temperature. We observe that all data can be placed on master-curves that depend only on a single density-and species-dependent and T-independent effective interaction energy, $E_∞$ (ρ). An isochoric fragility index is defined as an intrinsic property of a given liquid, that can help in rationalizing all the correlations between the glass properties below T g and the viscous slowing down just above $T_g$ from which they are made. Geometrical confinement of liquids is also a way to modify the dynamics of a liquid and the properties of a glass; it corresponds to a large number of situations encountered in nature. Another phase diagram $T − d$ (d= pore diameter) can be defined with a non-trivial pore size dependence of the glass transition, which is also strongly affected by surface interactions.

Herein, we investigate the charge transport and structural dynamics in the supercooled and glassy state of protic ionic material with an efficient interionic Grotthuss mechanism. We found that superprotonic properties of studied acebutolol hydrochloride (ACB-HCl) depend on thermodynamic conditions with the most favorable regions being close to the glass-transition temperature (Tg) and glasstransition pressure (Pg). To quantify the contribution of fast proton hopping to overall charge transport over a broad T−P space, we employed the density scaling concept, one of the most important experimental findings in the field of condensed matter physics. We found that isothermal and isobaric dc-conductivity (σdc) and dynamic light scattering (τα) data of ACB-HCl plotted as a function of (TVγ)−1 satisfy the thermodynamic scaling criterion with the ratio γσ/γα appearing as a new measure of fast charge transport in protic ionic glass-formers in the T−P plane. Such a universal factor becomes an alternative to the well-known Walden rule being limited to ambient pressure conditions.

Applicability of pure propane gas for microdosimetric measurements at photon energies relevant in brachytherapy is studied using the Monte Carlo-based FLUKA code. Monoenergetic photons in the energy range of 20–1250 keV and brachytherapy sources such as 103Pd, 125I, 169Yb, 192Ir, 137Cs and 60Co are considered in the study. Using the calculated values of energy deposited in the sensitive region of LET-1/2 tissue-equivalent proportional counter filled with pure propane gas and tissue-equivalent propane gas, values of density scaling factor for the site sizes of 1 and 8 μm are obtained. The study shows that density of propane gas should be lowered by a factor of about 0.93 for 169Yb, 192Ir, 137Cs and 60Co sources for the site sizes of 1–8 μm. For 125I source, the density of propane gas requires a scaling of 0.93 for 1 μm site size, whereas for site sizes 2–8 μm, density need not be altered. 103Pd source does not require density scaling for site sizes 1–8 μm.

It is demonstrated that properly reduced transport coefficients (self-diffusion, shear viscosity, and thermal conductivity) of Lennard-Jones fluids along isotherms exhibit quasi-universal scaling on the density divided by its value at the freezing point. Moreover, this scaling is closely related to the density scaling of transport coefficients of hard-sphere fluids. The Stokes-Einstein relation without the hydrodynamic diameter is valid in the dense fluid regime. The lower density boundary of its validity can serve as a practical demarcation line between gas-like and liquid-like regimes., 6 pages, 4 figures

This article presents a study on the viscous behaviour at high pressure of a synthetic oil, tris(2-ethylhexyl) trimellitate (TOTM). This fluid is being recommended as potential industrial reference material for high viscosity-high pressure measurements. Here we report new experimental viscosity values for TOTM at temperatures from 278.15 K to 373.15 K and at pressures to 150 MPa with a maximum viscosity of 2570 mPa s. The measurements have been performed using a high pressure falling-body apparatus and a Couette rotational viscometer. The experimental values obtained in this work are included in the database of a multinational project used recently to develop a reference correlation for TOTM (Wakeham et al., 2017). The universal viscosity-pressure coefficient of this fluid has been evaluated and compared with other oils, finding that it is close to the literature values of mineral oils. Moreover, we perform an analysis of the dependency of viscosity on pressure and temperature based on the density scaling concept.

This paper studies numerically the Weeks-Chandler-Andersen (WCA) system, which is shown to obey hidden scale invariance with a density-scaling exponent that varies from below 5 to above 500. This unprecedented variation makes it advantageous to use the fourth-order Runge-Kutta algorithm for tracing out isomorphs. Good isomorph invariance of structure and dynamics is observed over more than three orders of magnitude temperature variation. For all state points studied, the virial potential-energy correlation coefficient and the density-scaling exponent are controlled mainly by the temperature. Based on the assumption of statistically independent pair interactions, a mean-field theory is developed that rationalizes this finding and provides an excellent fit to data at low temperatures and densities.

RowHammer is a circuit-level DRAM vulnerability, first rigorously analyzed and introduced in 2014, where repeatedly accessing data in a DRAM row can cause bit flips in nearby rows. The RowHammer vulnerability has since garnered significant interest in both computer architecture and computer security research communities because it stems from physical circuit-level interference effects that worsen with continued DRAM density scaling. As DRAM manufacturers primarily depend on density scaling to increase DRAM capacity, future DRAM chips will likely be more vulnerable to RowHammer than those of the past. Many RowHammer mitigation mechanisms have been proposed by both industry and academia, but it is unclear whether these mechanisms will remain viable solutions for future devices, as their overheads increase with DRAM’s vulnerability to RowHammer.In order to shed more light on how RowHammer affects modern and future devices at the circuit-level, we first present an experimental characterization of RowHammer on 1580 DRAM chips (408$\times$DDR3, 652$\times$DDR4, and 520$\times$LPDDR4) from 300 DRAM modules (60$\times$DDR3, 110$\times$DDR4, and 130$\times$LPDDR4) with RowHammer protection mechanisms disabled, spanning multiple different technology nodes from across each of the three major DRAM manufacturers. Our studies definitively show that newer DRAM chips are more vulnerable to RowHammer: as device feature size reduces, the number of activations needed to induce a RowHammer bit flip also reduces, to as few as 9.6 k (4.8k to two rows each) in the most vulnerable chip we tested.We evaluate five state-of-the-art RowHammer mitigation mechanisms using cycle-accurate simulation in the context of real data taken from our chips to study how the mitigation mechanisms scale with chip vulnerability. We find that existing mechanisms either are not scalable or suffer from prohibitively large performance overheads in projected future devices given our observed trends of RowHammer vulnerability. Thus, it is critical to research more effective solutions to RowHammer.

The purpose of this paper is to estimate the magnetic field dependent critical current density scaling relation of NbTi used in a superconducting wire. The estimation problem is set using a finite element method based forward model solving the critical current of a wire in external magnetic fields. A sensitivity analysis is carried out to reveal the uncertainties in the process. It is shown that the methods provide accurate predictions of critical currents in a wire, but there are uncertainties related to the zero-field critical current density of the material. acceptedVersion

In this study, the optimum density scaling factors of phantom materials for a commercially available three‐dimensional (3D) dose verification system (Delta4) were investigated in order to improve the accuracy of the calculated dose distributions in the phantom materials. At field sizes of 10 × 10 and 5 × 5 cm2 with the same geometry, tissue‐phantom ratios (TPRs) in water, polymethyl methacrylate (PMMA), and Plastic Water Diagnostic Therapy (PWDT) were measured, and TPRs in various density scaling factors of water were calculated by Monte Carlo simulation, Adaptive Convolve (AdC, Pinnacle3), Collapsed Cone Convolution (CCC, RayStation), and AcurosXB (AXB, Eclipse). Effective linear attenuation coefficients (μ eff) were obtained from the TPRs. The ratios of μ eff in phantom and water ((μ eff)pl,water) were compared between the measurements and calculations. For each phantom material, the density scaling factor proposed in this study (DSF) was set to be the value providing a match between the calculated and measured (μ eff)pl,water. The optimum density scaling factor was verified through the comparison of the dose distributions measured by Delta4 and calculated with three different density scaling factors: the nominal physical density (PD), nominal relative electron density (ED), and DSF. Three plans were used for the verifications: a static field of 10 × 10 cm2 and two intensity modulated radiation therapy (IMRT) treatment plans. DSF were determined to be 1.13 for PMMA and 0.98 for PWDT. DSF for PMMA showed good agreement for AdC and CCC with 6 MV x ray, and AdC for 10 MV x ray. DSF for PWDT showed good agreement regardless of the dose calculation algorithms and x‐ray energy. DSF can be considered one of the references for the density scaling factor of Delta4 phantom materials and may help improve the accuracy of the IMRT dose verification using Delta4.

Recently Sanz et al. [A. Sanz, T. Hecksher, H.W. Hansen, J.C. Dyre, K. Niss, and U.R. Pedersen, Phys. Rev. Lett. 122, 055501 (2019).] reported that the scaling exponent gamma for tetramethyl-tetraphenyl-trisiloxane (DC704) varied with temperature; i.e., was not a material constant. Such a finding is at odds with previously published results on this compound and on more than 100 other liquids and polymers. The result of Sanz et al. comes from their measurement of a pressure dependence of the relaxation time at low temperature that becomes weaker with increasing pressure. Such a result is unphysical and contrary to the behavior of all known liquids. We re-measured this pressure dependence for DC704 and find it to be linear over the studied range. Thus, the conclusion of Sans et al. is incorrect; gamma for DC704 is state-point independent, in accord with other simple liquids and polymers., 2 pages, 2 figures

In this paper, we apply the cooperative free volume (CFV) rate model for pressure-dependent dynamics of glass-forming liquids and polymer melts. We analyze segmental relaxation times, [Formula: see text] , as a function of temperature (T and free volume ( [Formula: see text] , and make substantive comparisons with the density scaling approach. [Formula: see text] , the difference between the total volume (V and the volume at close-packing, is predicted independently of the dynamics for any temperature and pressure using the locally correlated lattice (LCL) equation-of-state (EOS) analysis of characteristic thermodynamic data. We discuss the underlying physical motivation in the CFV and density scaling models, and show that their key, respective, material parameters are connected, where the CFV b parameter and the density scaling [Formula: see text] parameter each characterize the relative sensitivity of dynamics to changes in T , vs. changes in V . We find [Formula: see text] , where [Formula: see text] is the value predicted by the LCL EOS at the ambient [Formula: see text] . In comparing the predictive power of the two models we highlight the CFV advantage in yielding a universal linear collapse of relaxation data using a minimal set of parameters, compared to the same parameter space yielding a changing functional form in the density scaling approach. Further, we demonstrate that in the low data limit, where there is not enough data to characterize the density scaling model, the CFV model may still be successfully applied, and we even use it to predict the correct [Formula: see text] parameter.

Under confinement, the properties of polymers can be much different from the bulk. Because of the potential applications in technology and hope to reveal fundamental problems related to the glass-transition, it is important to realize whether the nanoscale and macroscopic behavior of polymer glass-formers are related to each other in any simple way. In this work, we have addressed this issue by studying the segmental dynamics of poly(4-chlorostyrene) (P4ClS) in the bulk and upon geometrical confinement at the nanoscale level, in either one- (thin films on Al substrate) or two- (within alumina nanopores) dimensions. The results demonstrate that the segmental relaxation time, irrespective of the confinement size or its dimensionality, can be scaled onto a single curve when plotted versus γ /T with the same single scaling exponent, γ = 3.1, obtained via measurements at high pressures in bulk. The implication is that the macro- and nanoscale confined polymer dynamics are intrinsically connected and governed by the same underlying rules., SCOPUS: ar.j, info:eu-repo/semantics/published

A large class of liquids obey density scaling characterized by an exponent, which quantifies the relative roles of temperature and density for the dynamics. We present experimental evidence that the density-scaling exponent γ is state-point dependent for the glass formers tetramethyl-tetraphenyl-trisiloxane (DC704) and 5-polyphenyl ether (5PPE). A method is proposed that from dynamic and thermodynamic properties at equilibrium estimates the value of γ. The method applies at any state point of the pressure-temperature plane, both in the supercooled and the normal liquid regimes. We find that γ is generally state-point dependent, which is confirmed by reanalyzing data for 20 metallic liquids and two model liquids.

We present investigations of the charge transport in an ionic glass-former carvedilol dihydrogen phosphate (CP) at various T- P- V thermodynamic conditions in terms of density scaling concept. The studied material was found to reveal superprotonic properties both at ambient and elevated pressure, as proved by the Walden rule. Surprisingly, from the isobaric conductivity data, the relaxation times τ

To keep Moore's law alive, 2D materials are considered as a replacement for Si in advanced nodes due to their atomic thickness, which offers superior performance at nm dimensions. In addition, 2D materials are natural candidates for monolithic integration which opens the door for density scaling along the 3rd dimension at reasonable cost. This paper highlights the obstacles and paths to a scaled 2D CMOS solution. The baseline requirements to challenge the advanced Si nodes are defined both with a physical compact model and TCAD analysis, which allows us to identify the most promising 2D material and device design. For different key challenges, possible integrated solutions are benchmarked and discussed. Finally we report on the learning from our first lab to fab vehicle designed to bridge the lab and IMEC's 300mm pilot line.

Transistor performance continues to improve with density scaling and move to FinFET architectures. However, feature size reduction increases parasitic contact and interconnect resistance. This degrades the power-performance equation. To address the resistance bottleneck; new materials, new fill technologies and new integration schemes are in play. This paper reviews metallization trends for contact and interconnect as the industry prepares for 7nm node production and looks towards developing 5 and 3nm nodes.

As the 2D NAND Flash scaling plateaued due to physical and electrical scaling limitations, 3D NAND emerged as a strong successor to continue the scaling trend. 3D NAND has rapidly achieved maturity and is already in the 3rd and 4th generation of technology with the total number of layers reaching 96 active layers. The improved cell characteristics of 3D NAND have enabled 4bits/cell capability, allowing for further bit density scaling. This paper describes some of the recent innovations in the 3D NAND technology and the key challenges ahead for continued scaling.

The density scaling of n = 1 error field penetration is investigated under radio-frequency (RF)-dominant heated L-mode discharges in the EAST tokamak. It is found that the density scaling of the threshold field strength for error field penetration in lower-hybrid current drive (LHCD) plasmas is about b r ∝ n e 0.4 , where b r represents the error field amplitude. The results show a weaker density dependence compared to that observed in the previous ohmic heated discharges (Wang et al 2018 Nucl. Fusion 58 056024). For a better understanding of the density scaling, it is compared with field penetration theories, and it is found that it lies in the Waelbroeck regime. The observed scaling is consistent with that evaluated with the magnetohydrodynamic (MHD) theory on error field penetration, for which all the physical parameters are determined experimentally. Due to the density dependence of LHCD heating efficiency, the stronger negative correlation between density and temperature results in a weaker density scaling in these LHCD plasmas. Using realistic parameters under LHCD and ohmic heating as input, respectively, the numerical results based on a reduced MHD model reproduce well the scaling from the error field penetration theory and the observations. Besides, the density scaling in various tokamak operational regimes is also numerically investigated. This provides an excellent validation of MHD theory on error field penetration in the RF-dominant heated L-mode discharges.

A simple density functional theory (DFT) scheme is proposed for estimating negative vertical electron affinities of neutral systems, based on a consideration of the integer discontinuity and density scaling homogeneity. The key feature is the derivation of two system-dependent exchange-correlation functionals, one appropriate for the electron deficient side of the integer and one appropriate for the electron abundant side. The electron affinity is evaluated as a linear combination of frontier orbital energies from self-consistent Kohn-Sham calculations on the neutral system using these functionals. For two assessments comprising a total of 43 molecules, the scheme provides electron affinities that are in good agreement with experimental values and which are an improvement over those from the DFT method of Tozer and De Proft [ J. Phys. Chem. A 2005 , 109 , 8923 ]. The scheme is trivial to implement in any Kohn-Sham program, and the computational cost is that of a series of generalized gradient approximation Kohn-Sham calculations. More generally, the study provides a prescription for performing low-cost, self-consistent Kohn-Sham calculations that yield frontier orbital energies that approximately satisfy the appropriate Koopmans conditions, without the need for exact exchange.

Levy and Zahariev [Phys. Rev. Lett. 113 113002 (2014)] have proposed a new approach for performing density functional theory calculations, termed direct energy Kohn–Sham (DEKS) theory. In this approach, the electronic energy equals the sum of orbital energies, obtained from Kohn–Sham-like orbital equations involving a shifted Hartree-exchange-correlation potential, which must be approximated. In the present study, density scaling homogeneity considerations are used to facilitate DEKS calculations on a series of atoms and molecules, leading to three nonlocal approximations to the shifted potential. The first two rely on preliminary Kohn–Sham calculations using a standard generalized gradient approximation (GGA) exchange-correlation functional and the results illustrate the benefit of describing the dominant Hartree component of the shift exactly. A uniform electron gas analysis is used to eliminate the need for these preliminary Kohn–Sham calculations, leading to a potential with an unconventional form that yields encouraging results, providing strong motivation for further research in DEKS theory.

In orbital-free density functional theory only a single equation, the so-called Euler equation, has to be solved for any system instead of the Kohn–Sham equations. The Euler equation is a Schrodinger-like equation for the square root of the density. This equation contains an extra potential, the so-called Pauli potential, in addition to the usual Kohn–Sham potential. Equations for the Pauli potential, the relationship of the Pauli potential and Pauli energy are reviewed. A derivation of the Euler equation via density scaling is presented.

The relaxation dynamics in two van der Waals bonded liquids and one hydrogen-bonding molecular liquid are studied as a function of pressure and temperature by incoherent neutron scattering using simultaneous dielectric spectroscopy. The dynamics are studied in a range of alpha relaxation times from pico- to milliseconds, primarily in the equilibrium liquid state. In this range, we find that isochronal superposition and density scaling work not only for the two van der Waals liquids but also for the hydrogen-bonding liquid, though the density scaling exponent is much smaller for the latter. Density scaling and isochronal superposition are seen to break down for intra-molecular dynamics when it is separated in time from the alpha relaxation, in close agreement with previous observations from molecular dynamics simulations.

A transitiometric method for determining isobaric thermal expansivity of liquid 1,4-dichlorobutane and 1-bromo-4-chlorobutane as a function of temperature and pressure through calorimetric measurements against pressure is described. Isobaric thermal expansivities of haloalkanes were determined over the temperature range from 273.15 to 423.15 K at pressures up to 200 MPa. Experimental results were used to model the general density scaling-based equation of state and to analyze the pressure–temperature behavior of the thermal expansion coefficient. We confirmed that investigated liquids present a characteristic pressure range in which (∂αP/∂T)P = 0.

It has been recently shown that one can understand the Prigogine-Defay ratio at the glass transition in terms of freezing into one of the many inherent states of the undercooled liquid. In the present paper, the treatment is extended to the dynamics at the glass transition to show the connection to isomorphism and density scaling. In addition, the energy limits for stable inherent states are discussed., Comment: paper accepted for Proceedings IDMRCS 2013 in Barcelona, special issue of Journal of Non-Crystalline Solids

In this work, we will review possible technology options for next generation wireless communication. Next to the introduction of specific device architectures and materials, dissimilar from standard Si CMOS, the challenge will lie in the co-integration of these non-Si technologies with CMOS to enable power efficient systems with high performance, in this case high speed and output power, and reduced form factor. Next to monolithic integration, sequential 3D, currently been investigated for LOGIC density scaling, can be one of the enablers, allowing to combine technologies with very different needs at a finer grain and thus higher density than traditional 3D-SOC and 3D-IC technologies.

Spatial association of clumps from different tracers turns out to be a valuable tool to determine the physical properties of molecular clouds. It provides a reliable estimate for the $X$-factors, serves to trace the density of clumps seen in column densities only and allows to measure the velocity dispersion of clumps identified in dust emission. We study the spatial association between clump populations, extracted by use of the GAUSSCLUMPS technique from $^{12}$CO (1-0), $^{13}$CO (1-0) line maps and Herschel dust-emission maps of the star-forming region Rosette, and analyse their physical properties. All CO clumps that overlap with another CO or dust counterpart are found to be gravitationally bound and located in the massive star-forming filaments of the molecular cloud. They obey a single mass-size relation $M_{\rm cl}\propto R_{\rm cl}^\gamma$ with $\gamma\simeq3$ (implying constant mean density) and display virtually no velocity-size relation. We interpret their population as low-density structures formed through compression by converging flows and still not evolved under the influence of self-gravity. The high-mass parts of their clump mass functions are fitted by a power law ${\rm d}N_{\rm cl}/{\rm d}\,\log M_{\rm cl}\propto M_{\rm cl}^{\Gamma}$ and display a nearly Salpeter slope $\Gamma\sim-1.3$. On the other hand, clumps extracted from the dust-emission map exhibit a shallower mass-size relation with $\gamma=2.5$ and mass functions with very steep slopes $\Gamma\sim-2.3$ even if associated with CO clumps. They trace density peaks of the associated CO clumps at scales of a few tenths of pc where no single density scaling law should be expected., Comment: 23 pages, 13 figures, 8 tables; accepted for publication in MNRAS

The application of the new quantitative elastohydrodynamics, which employs real properties of the liquid lubricant, to practical tribology problems obviously requires property measurements at high ...

Dielectric relaxation measurements, in combination with density determinations, on tetramethyl tetraphenyl trisiloxane (DC704) over an unusually broad range of temperatures and pressures revealed a state-point dependency in its density scaling exponent. This is the first unambiguous experimental demonstration of a breakdown of density scaling in a nonassociated glass-forming material, and unanticipated for DC704, among the "simplest" of liquids, having a constant breadth of the relaxation dispersion and a Prigogine-Defay ratio near unity characteristic of approximate single-parameter systems. We speculate that the anomalous behavior has origins in the large value of its scaling exponent and relative flexibility of the chemical structure.

Dielectric spectra were obtained on a low molecular weight poly(methyl methacrylate) (PMMA) over a range of temperatures (331 < T (K) < 386) at pressures approaching 0.8 GPa. The α relaxation times...

New experimental viscosity values for three ionic liquids, 1-butyl-2,3-dimethylimidazolium tris(pentafluoroethyl)trifluorophosphate, 1-(2-methoxyethyl)-1-methyl-pyrrolidinium tris(pentafluoroethyl) trifluorophosphate and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, are reported in this work. The measurements were carried out using a falling-body viscometer within the temperature range from (313.15 to 363.15) K at pressures up to 150 MPa. These values were correlated as a function of temperature and pressure with four different equations. Moreover, we perform an analysis of the dependency of viscosity on pressure and temperature based on the density scaling concept for these fluids and other three ionic liquids recently studied with the same device. © 2013 Elsevier Ltd. All rights reserved.

Despite the widening gap between scaled feature sizes and optical exposure wavelengths, integrated circuit transistor density so far has kept pace with Moore’s Law. The absence of viable lens materials for smaller wavelengths precludes exposure wavelengths below 193nm for refractive optical tools. Reflective optical exposure tools using extreme ultraviolet (EUV) light have been under intense development over the past decade but, mainly due to light source power shortfalls, have not yet achieved performance levels needed for high volume production. Alternatives to optical pattern transfer are also under development, including electron beam direct write, and nano-imprint lithography (NIL) systems. Until EUV or an alternative technology meets high-volume production requirements, next-generation integrated circuit process nodes will rely upon 193nm immersion lithography tools augmented with novel optical and process technologies to achieve feature pitches below the single exposure resolution limit. Squeezing more information through the limited spatial bandwidth of 193nm systems imposes limitations on design layout freedoms. Designers can no longer draw arbitrary patterns even when minimum line and space dimension constraints are met. The types of layout restrictions demanded by alternative lithography approaches, and their impact on patterning resolution and noise trade-offs, are explored in the context of evolving IC end-use values, such as density, performance, and power efficiency.

We present a new method that allows direct measurements of the glass transition temperature ${T}_{g}$ at pressures up to 4.55 GPa in the glass-forming liquid cumene (isopropylbenzene). This new method uses a diamond anvil cell and can measure ${T}_{g}$ at pressures of 10 GPa or greater. Measuring ${T}_{g}$ at the $\mathrm{glass}\ensuremath{\rightarrow}\mathrm{liquid}$ transition involves monitoring the disappearance of pressure gradients initially present in the glass, but also takes advantage of the large increase in the volume expansion coefficient ${\ensuremath{\alpha}}_{p}$ at ${T}_{g}$ as the supercooled or superpressed liquid is entered. Accurate ${T}_{g}(P)$ values in cumene allow us to show that density scaling holds along this isochronous line up to pressures much higher than any previous study, corresponding to a density increase of 29%. Our results for cumene over this huge compression range yield ${\ensuremath{\rho}}^{\ensuremath{\gamma}}/T=C$, where C is a constant and where $\ensuremath{\gamma}=4.77\ifmmode\pm\else\textpm\fi{}0.02$ for this nonassociated glass-forming system. Finally, high-pressure cumene viscosity data from the literature taken at much lower pressures and at several different temperatures, corresponding to a large dynamic range of nearly 13 orders of magnitude, are shown to superimpose on a plot of $\ensuremath{\eta}$ vs ${\ensuremath{\rho}}^{\ensuremath{\gamma}}/T$ for the same value of $\ensuremath{\gamma}$.