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The temporal evolution of weak shocks in radiative media is theoretically investigated in this work. The structure of radiative shocks has traditionally been studied in a stationary framework. Their systematic classification is complex because layers of optically thin and thick regions alternate to form a radiatively-driven precursor and a temperature-relaxation layer, between which the hydrodynamic shock is embedded. In this work, we analyze the formation of weak shocks when two radiative plasmas with different pressures are put in contact. Applying a reductive perturbative method yields a Burgers-type equation that governs the temporal evolution of the perturbed variables including the radiation field. The conditions upon which optically thin and thick solutions exist have been derived and expressed as a function of the shock strength and Boltzmann number. Below a certain Boltzmann number threshold, weak shocks always become optically thick asymptotically in time, while thin solutions appear as transitory structures. The existence of an optically thin regime is related to the presence of an overdense layer in the compressed material. Scaling laws for the characteristic formation time and shock width are provided for each regime. The theoretical analysis is supported by FLASH simulations, and a comprehensive test-case has been designed to benchmark radiative hydrodynamic codes., Comment: Approved in Phys. Rev. E

Automatic Compliance Checking (ACC) within the Architecture, Engineering, and Construction (AEC) sector necessitates automating the interpretation of building regulations to achieve its full potential. Converting textual rules into machine-readable formats is challenging due to the complexities of natural language and the scarcity of resources for advanced Machine Learning (ML). Addressing these challenges, we introduce CODE-ACCORD, a dataset of 862 sentences from the building regulations of England and Finland. Only the self-contained sentences, which express complete rules without needing additional context, were considered as they are essential for ACC. Each sentence was manually annotated with entities and relations by a team of 12 annotators to facilitate machine-readable rule generation, followed by careful curation to ensure accuracy. The final dataset comprises 4,297 entities and 4,329 relations across various categories, serving as a robust ground truth. CODE-ACCORD supports a range of ML and Natural Language Processing (NLP) tasks, including text classification, entity recognition, and relation extraction. It enables applying recent trends, such as deep neural networks and large language models, to ACC., Comment: This is a preprint of an article submitted to the Scientific Data Journal

Pattern recognition and machine learning techniques are known to play an emerging role for studying underlying physics of light-matter interaction. While on the subject, photon condensation and Anti-Stokes cooling remain compelling phenomena of laser-underdense plasma interaction. In this work, the interaction of a 1064 nm continuum-wave laser with inductively-coupled plasma (ICP) of Mercury(Hg) has been studied by probabilistic pattern recognition over observed time resolved spectral data.3D vector fields obtained by the probabilistic pattern recognition over spectral database proficiently illuminates the analogue black hole (ABH) and its sonic horizon in which homoclinic orbit Whistler waves are exited. Vector spectra show the collective behavior of condensation and anti-Stokes cooling is due to the electronic transitions of Hg1 trapped by the phonon sink of ABH of laser. Modeling of subsonic phonon vector spectrum obtained by the probabilistic linear discriminant analysis(PLDA) estimates the 0.70 nanoKelvin of temperature of the sink region of ABH.

Magneto-Inertial Fusion Technology Inc. has been working on a Z-pinch concept where a high atomic number liner is compressing a fusion fuel (deuterium-deuterium, or deuterium-tritium) target. The viability of this so called Staged Z-pinch (SZP) concept as a potential high-gain fusion energy source has been questioned in a recent publication by Lindemuth et al [1]. The authors attempted to reproduce previously published MACH2 simulation results [2-4] for Z-machine parameters using three different MHD codes: Hydra, Raven and MHRDR. Their conclusion was that "there is no conceivable modification of the parameters that would lead to high-gain fusion conditions using these other codes". Although they used well established MHD codes to check the SZP concept, and correct input current profiles, we show that their Lagrangian formalism was likely not treating the vacuum/liner boundary properly. Proper modeling using Lagrangian, Eulerian or Adaptive Lagrangian-Eulerian (ALE) formalism indeed confirms that fusion energy production > 1 MJ can be expected without alpha heating, and significantly higher if alpha heating is included. It is shown that magnetosonic shocks play an important role in preheating the target plasma and in piling liner mass at the liner/target interface, which substantially increases the ram pressure just before the pinch stagnation time.

In this paper, some statistical distributions of wide pairs included in Double Star Catalogue are investigated. Frequency distributions and testing hypothesis are derived for some basic parameters of visual binaries. The results reached indicate that, it was found that the magnitude difference is distributed exponentially, which means that the majority of the component of the selected systems is of the same spectral type. The distribution of the mass ratios is concentrated about 0.7 which agree with Salpeter mass function. The distribution of the linear separation appears to be exponentially, which contradict with previous studies for close binaries., Comment: 15 pages, 6 figures and 12 tables

To determine the velocity ellipsoid of the solar neighborhood white dwarfs, we use the space velocity components of stars. Two samples of white dwarfs are used, 20 pc and 25 pc samples. Beside the two main samples, the solar velocity and velocity dispersions are calculated for the four subsamples, namely DA, non - DA, hot and cool white dwarfs. Comparison between the results of 20 pc sample and those of 25 pc sample gives good agreement, while the comparison between the other subsamples gives bad agreement. Dependence of the velocity dispersions and solar velocity on the chemical composition and effective temperatures are discussed., Comment: 13 pages; 1 figure, 7 tables

We simulate fusion in a Z-pinch; where the load is a xenon-plasma liner imploding onto a deuterium-tritium plasma target and the driver is a 2 MJ, 17 MA, 95 ns risetime pulser. The implosion system is modeled using the dynamic, 2-1/2 D, radiation-MHD code, MACH2. During implosion a shock forms in the Xe liner, transporting current and energy radially inward. After collision with the DT, a secondary shock forms pre-heating the DT to several hundred eV. Adiabatic compression leads subsequently to a fusion burn, as the target is surrounded by a flux-compressed, intense, azimuthal-magnetic field. The intense-magnetic field confines fusion $\alpha$-particles, providing an additional source of ion heating that leads to target ignition. The target remains stable up to the time of ignition. Predictions are for a neutron yield of $3.0\times 10^{19}$ and a thermonuclear energy of 84 MJ, that is, 42 times greater than the initial, capacitor-stored energy.

The structure of the magnetotail is investigated in a laboratory simulated magnetosphere. Particular emphasis is placed on the region of distant magnetotail where the closed field line region of the plasma sheet terminates and the process of reconnection takes place. Our study builds upon the previous investigation of the magnetotail where the main results were based on the magnetic field measurements in the tail region of the simulated magnetosphere. In this paper, more elaborate measurements of plasma flow and electric field are presented. Besides these measurements, this region of distant magnetotail is also explored by high resolution imaging with a gated optical imager (GOI) and by digital image analysis. These images clearly reveal a Y-type magnetic neutral line for the northward 'interplanetary' field (IMF) and a usual X-type for the southward IMF that confirms our previous results deduced from the magnetic field measurements. In the neighborhood of these neutral points a strong component of dawn to dusk electric field (E(sub y)) and a counterstreaming plasma flow is also observed. Plasma flow is measured by using a double sided Faraday cup which is also used to measure the y-component of tail current (J(sub y)) at different locations. These measurements reveal that the tail current is not carried by ions as previously thought, rather it is carried by electrons alone.

Experimental models and global computer simulations are used to study the field structure and location of the site where the closed plasma sheet terminates. The site - also called the 'distant neutral line' - is described with references to several solar-wind parameters that can change its characteristic properties. A laboratory experiment is then conducted in which a flowing magnetized plasma beam interacts with a dipole field. High-latitude nightside reconnection is supported by the simulation results comparing the effects of northward and southward interplanetary fields. The results support the models by Dungey (1961, 1963) that predict high-latitude nightside reconnection and an open magnetosphere. A significant finding is that a magnetic neutral line at the closed-field line region is not a necessary component of the region.

The interaction of a magnetized plasma beam with a stationary dipole field, analogous to the interaction of the solar wind with the earth's magnetosphere, is explored in a laboratory experiment. Experimental parameters are chosen to scale qualitatively similar to the parameters in the earth's magnetosphere. It is found that the magnetization of the laboratory 'solar wind', generated by injecting a plasma across a preexisting magnetic field, requires a certain minimum magnetic field strength. Differences between the resulting magnetospheres for northward and southward 'solar wind' or 'interplanetary' magnetic fields (IMF) are demonstrated by global pictures and by magnetic field measurements above the north polar region. These measurements show patterns of the variation of the transverse field component which are similar to those found by satellite measurements above the earth. This indicates the presence of similar field-aligned current systems. Particularly, the presence (for northward IMF) and absence (for southward IMF) of the pattern attributed to the 'NBZ' (northward Bz) current system are demonstrated.

The magnetization of a high-beta (plasma energy density/magnetic-field energy density) hydrogen-plasma beam injected into a vacuum transverse magnetic field is studied experimentally. Nominal parameters were Ti = 1 eV, Te = 5 eV, n = 3 x 10 to the 13th/cu cm or less, v(i) = 7 x 10 to the 6th cm/sec or less, t(pulse) less than 70 microsec, and Bz = 300 G or less. Plasma characteristics were measured for a wide beam and a downstream distance, x = 300 rho(i) or less, where x is the downstream distance and rho(i) is the ion gyroradius. A brief initial state of diamagnetic propagation is observed, followed by magnetized propagation accompanied by beam compression transverse to B with as much as a factor of 4 increase in density and a slight drift of the beam in the ion Lorentz force direction.

The laboratory simulation of the interaction of the solar wind with a comet is used to study the cometary neural gas ionization. The experiment is carried out in the UCR T-1 facility with an ice ball as the comet model. Photographs and data are taken with a variety of values of the solar wind velocity, interplanetary magnetic field (IMF), and comet configurations. The results show that the cometary neutral gas ionization depends on both the velocity of the solar wind and the interplanetary magnetic field. The plasma cloud surrounding the comet is visible only when the solar wind velocity and IMF are both above certain minimum values. This velocity dependent phenomena is explained by Alfven's critical ionization velocity effect. The critical magnetic field may be explained by assuming two stream lower hybrid instability as a triggering mechanism for the ionization of the neutral gas by plasma flow. Critical upper and lower limits for the magnetic field, required by anomalous ionization, are also derived that satisfy the experimental observations.

A finite element computational model for the nonlinear analysis of reinforced concrete solid, stiffened and cellular plates is briefly outlined. Typically, Mindlin elements are used to model the plates whereas eccentric Timoshenko elements are adopted to represent the beams. The layering technique, common in the analysis of reinforced concrete flexural systems, is incorporated in the model. The proposed model provides an inexpensive and reasonably accurate approach which can be extended for use with voided plates.