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When a shaped charge jet penetrates a semi-infinite target, penetration proceeds in both axial and radial directions. To quantify the dimensions of the resulting radial cavity, this paper introduces two fully compressible models for radial cavity growth. These models are developed by extending the established fully compressible framework for axial penetration, incorporating the Szendrei and Wen models of radial cavity growth. Numerical methods are employed to solve the proposed models. Comparison with experimental data from shaped charge jet penetration into soil targets demonstrates that the two proposed fully compressible radial cavity models outperform the classical Szendrei approach. Among them, the model based on the Wen formulation achieves the highest predictive accuracy. The proposed models enable more reliable prediction of radial cavity growth in highly compressible targets subjected to shaped charge jet impact. The findings offer theoretical support for analyzing cavity formation in environments with high compressibility.

Cholesterol is an integral component of eukaryotic cell membranes and a key molecule in controlling membrane fluidity, organization, and other physicochemical parameters. It also plays a regulatory function in antibiotic drug resistance and the immune response of cells against viruses, by stabilizing the membrane against structural damage. While it iswell understood that, structurally, cholesterol exhibits a densification effect on fluid lipid membranes, its effects on membrane bending rigidity are assumed to be nonuniversal; i.e., cholesterol stiffens saturated lipid membranes, but has no stiffening effect on membranes populated by unsaturated lipids, such as 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). This observation presents a clear challenge to structure–property relationships and to our understanding of cholesterol-mediated biological functions. Here, using a comprehensive approach—combining neutron spin-echo (NSE) spectroscopy, solid-state deuterium NMR (²H NMR) spectroscopy, and molecular dynamics (MD) simulations—we report that cholesterol locally increases the bending rigidity of DOPC membranes, similar to saturated membranes, by increasing the bilayer’s packing density. All three techniques, inherently sensitive to mesoscale bending fluctuations, show up to a threefold increase in effective bending rigidity with increasing cholesterol content approaching a mole fraction of 50%. Our observations are in good agreement with the known effects of cholesterol on the area-compressibility modulus and membrane structure, reaffirming membrane structure–property relationships. The current findings point to a scale-dependent manifestation of membrane properties, highlighting the need to reassess cholesterol’s role in controlling membrane bending rigidity over mesoscopic length and time scales of important biological functions, such as viral budding and lipid–protein interactions.

We studied recent observation data of pulsar masses and radii of PSR J0740+6620, PSR J0348+0432, and PSR J1614–2230 from different measurements, based on the extended version of σ-ω model. Throughout our analysis, we assumed that these pulsars are maximal-mass compact stars, thus we applied the core approximation. Based on the linear relation between the microscopic and macroscopic parameters of compact stars evaluated by our model, we estimated the average Landau mass m L = 752.46 - 42.5 + 49.1 MeV and compressibility K = 261.7 - 28.0 + 57.2 MeV.

We present an optomechanical method for locally measuring the rheological properties of complex fluids in the ultra-high frequency range (UHF). A mechanical disk of microscale volume is used as an oscillating probe that monitors a liquid at rest, while the oscillation is optomechanically transduced. An analytical model for fluid-structure interactions is used to deduce the rheological properties of the liquid. This method is calibrated on liquid water, which despite pronounced compressibility effects remains Newtonian over the explored range. In contrast, liquid 1-decanol exhibits a non-Newtonian behavior, with a frequency-dependent viscosity showing two relaxation times of 797 and 151 picoseconds, associated to supramolecular and intramolecular processes. A shear elastic response appears at the highest frequencies, whose value allows determining the volume of a single liquid molecule. UHF optomechanical micro-rheology provides direct mechanical access to the fast molecular dynamics in a liquid, in a quantitative manner and within a sub-millisecond measurement time. An optomechanical probe measures the rheological properties of liquids in a microscopic volume. Operating at ultra-high frequency, it reveals compressibility effects in water, while unveiling non-Newtonian behavior in a long chain alcohol.

The classical water-wave theory often neglects water compressibility effects, assuming acoustic and gravity waves propagate independently due to their disparate spatial and temporal scales. However, nonlinear interactions can couple these wave modes, enabling energy transfer between them. This study adopts a dynamical systems approach to investigate acoustic–gravity wave triads in compressible water flow, employing phase-plane analysis to reveal complex bifurcation structures and identify steady-state resonant configurations. Through this framework, we identify specific parameter conditions that enable complete energy exchange between surface and acoustic modes, with the triad phase (also known as the dynamical phase) playing a crucial role in modulating energy transfer. Further, incorporating spatial dependencies into the triad system reveals additional dynamical effects that depend on the wave velocity and resonance conditions: we observe that travelling-wave solutions emerge, and their stability is governed by the Hamiltonian structure of the system. The phase-plane analysis shows that, for certain velocity regimes, the resonance dynamics remains similar to the spatially independent case, while in other regimes, bifurcations modify the structure of resonant interactions, influencing the efficiency of energy exchange. Additionally, modulated periodic solutions appear, exhibiting changes in wave amplitudes over time and space, with implications for wave-packet stability and energy localisation. These findings enhance the theoretical understanding of acoustic–gravity wave interactions, offering potential applications in geophysical phenomena such as oceanic microseisms.

This paper introduces a novel framework for understanding the fundamental experience of rūparealm1 through the individual mind2 governing causation. We present a sensor-based model that captures the inseparable connection between the mind and rūparealm. The framework analyses fundamental qualities of rūparealm detectable through the sensory organs and mind, such as stiffness, viscosity, compressibility, temperature, colour, smell, taste, reactivity, space, sound, and a few more, totalling 28. Specific eight of these qualities collectively form the Suddhāṭṭhaka3 which represents the common fundamental experience of all forms of rūparealm. We emphasise that all experiences are mind-made, and secondary constructs, including mathematics and physics, arise from the analytical processing of these fundamental experiences. Furthermore, we propose Buddhist meditation as a tool to explore and train the mind to be aware of fundamental experiences before undergoing cognitive processes. The paper discusses contemporary research unifying relativity, quantum mechanics, and consciousness, positing that consciousness is the governance process of universal laws. The discussion emphasises the role of the mind in constructing the perceived reality and advocates the importance of incorporating the mind into fundamental physics when modelling causation.

The material of the work is an integral element of the problem of determining the stress-strain state of various types of arrays, including various forms of recess. In the current problem, the stress state is determined in the plastic zone near an ellipsoidal recess for a compressible mass. There is no pressure inside the recess, and at a considerable distance there is compression by mutually perpendicular forces. A solution is obtained for the case of the first approximation by the small parameter method. The results can be applied in the field of structural mechanics, mining business, and other related fields.

A hypersonic, spatially evolving turbulent boundary layer at Mach 12.48 with a cooled wall is analysed by means of direct numerical simulations. At the selected conditions, massive kinetic-to-internal energy conversion triggers thermal and chemical non-equilibrium phenomena. Air is assumed to behave as a five-species reacting mixture, and a two-temperature model is adopted to account for vibrational non-equilibrium. Wall cooling partly counteracts the effects of friction heating, and the temperature rise in the boundary layer excites vibrational energy modes while inducing mild chemical dissociation of oxygen. Vibrational non-equilibrium is mostly driven by molecular nitrogen, characterized by slower relaxation rates than the other molecules in the mixture. The results reveal that thermal non-equilibrium is sustained by turbulent mixing: sweep and ejection events efficiently redistribute the gas, contributing to the generation of a vibrationally under-excited state close to the wall, and an over-excited state in the outer region of the boundary layer. The tight coupling between turbulence and thermal effects is quantified by defining an interaction indicator. A modelling strategy for the vibrational energy turbulent flux is proposed, based on the definition of a vibrational turbulent Prandtl number. The validity of the strong Reynolds analogy under thermal non-equilibrium is also evaluated. Strong compressibility effects promote the translational–vibrational energy exchange, but no preferential correlation was detected between expansions/compressions and vibrational over-/under-excitation, as opposed to what has been observed for unconfined turbulent configurations.

In China, the exploration and development of low-rank coalbed methane (CBM) resources are in the early stage, and in-situ pyrolysis is an effective technology for mining of low-rank CBM resources. In this paper, N 2 adsorption method and high-pressure mercury injection test were used to study the pore structure characteristics of coal samples by water vapor injection, and the pore size boundaries of the two test methods were determined. From the continuous pore space distribution model, Frenkel–Halsey–Hill model, Menger sponge model, a new method of pore size classification is proposed: (I) (> 10,000 nm), (II) (1000–10,000 nm), (III) (100–1000 nm), (IV) ( x (pore diameter boundary)–100 nm), (V) (10– x  nm), (VI) (< 10 nm). The results were not inconsistent with the Hodot classification method, indicating that the new pore classification scheme is reliable. Meanwhile, the relationship between pyrolysis temperature and matrix compressibility is discussed, and it was found that transition pores had a significant effect on matrix compressibility. Pyrolysis weakened the connection between coal particles, improved the development of porosity, and led to high matrix compressibility. Furthermore, when pyrolysis temperature was < 400 °C and matrix compression effect was dominant, poor pore connectivity resulted in a low level of matrix compressibility; when pyrolysis temperature was > 500 °C and pore filling effect was dominant, high level of matrix compressibility was promoted.