Density Model Research Articles

Comprehensive study on deep eutectic solvent density based on various EoSs: SRK, PT, VTSRK, sPC-SAFT

In this communication, the capability of a two-parameter cubic equation of state (EoS) i.e. Soave-Redlich-Kwong (SRK) EoS to predict the density behavior of deep eutectic solvents (DESs) in the wide range of temperature conditions and at atmospheric pressure, was improved using the volume-translated concept. At first, the c-parameter of 139 DESs (1793 experimental data points) was obtained referring to volume-translated SRK (VTSRK) EoS. The obtained results were compared with the original SRK and Patel-Teja (PT) EoSs and sPC-SAFT (simplified perturbed chain statistical associating fluid theory) EoS. Afterward, three c-parameter correlations were recommended based on molecular weight and acentric factor (Case 1), acentric factor (Case 2), and critical compressibility factor (Case 3). The capability of recommended c-parameter correlations was investigated by density modeling of 67 new DESs systems (419 experimental data). The AARD% (average absolute relative deviation) of Case 1, Case 2, Case 3 and sPC-SAFT EoS was 4.24%, 3.24%,4.19% and 0.5677%, respectively.

Effect of annealing temperature on the morphological, structural, and optical properties of zinc oxide nanostructures prepared by the sol–gel spin coating technique

ABSTRACT This study investigates the impact of different annealing temperatures on the properties of zinc oxide (ZnO) films, particularly at lower temperatures (150-550°C). The films were synthesized using the sol-gel technique, with zinc acetate dihydrate (ZAD) as the precursor and ethanolamine (MEA) as the stabilizing agent. Surface morphology, structural, and optical properties of the films were examined using various techniques. X-ray diffraction confirmed the (002) wurtzite crystal structure, while crystallite size, strain, stress, energy density model, and dislocation density are estimated using three models of Williamson-Hall (W-H) approach.Raman data indicated the hexagonal wurtzite structure of the film. Optical analysis showed good transmittance, with a bandgap estimated between 3.32 and 3.56 eV for all samples. SEM image analysis revealed a nanowall structure in the ZnO thin film annealed at 150°C. However, increasing the annealing temperature led to a more pronounced wrinkled morphology.

Analytical Modelling of Inhomogeneous Energy Density Driven (IEDD) Instability in a Magnetized Dusty Plasma Cylinder

Analytical Modelling of Inhomogeneous Energy Density Driven (IEDD) Instability in a Magnetized Dusty Plasma Cylinder

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The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT with the use of the γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma $$\\end{document} activation and off-line γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma $$\\end{document}-ray spectroscopy. 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The measured values, as well as the literature data, significantly (by more that an order of magnitude) exceed the theoretical flux-averaged cross-sections ⟨σ(Eγmax)⟩th\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\langle {\\sigma (E_{\\mathrm{\\gamma max}})}\\rangle _{\ extrm{th}}$$\\end{document}. 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A comparative analysis of the calculated total cross-sections from the TALYS computation for the reactions 181Ta(γ,p)180Hf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${^{181}\ extrm{Ta}}(\\gamma ,p)^{180}\ extrm{Hf}$$\\end{document} and 181Ta(γ,n)180Ta\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${^{181}\ extrm{Ta}}(\\gamma ,n)^{180}\ extrm{Ta}$$\\end{document} was performed. It was shown that the photoproton (γ,p)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(\\gamma ,p)$$\\end{document} to photoneutron (γ,n)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(\\gamma ,n)$$\\end{document} strength ratio is consistent with the estimates based on the isospin selection rules and the value from the (e,e′p)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(e,e'p)$$\\end{document} experiment.

Crustal structure of onshore-offshore Atlantic Canada and environs from constrained 3-D gravity inversion using variable mesh depths

SUMMARYAtlantic Canada encompasses geological evidence of the orogenic and rifting episodes that inspired the development of the theory of plate tectonics and the fundamental concept of the Wilson cycle. To provide a regional crustal-scale view that can complement surface mapping studies and sparse seismological investigations, an onshore–offshore 3-D constrained gravity inversion methodology is proposed involving incorporation of topography and an inversion mesh that is laterally variable in terms of its maximum depth extent. A 3-D density anomaly model for the entirety of Atlantic Canada and its environs is generated, with the inverted density distribution structure and extracted isodensity surfaces showing excellent correspondence with independent and co-located controlled source and passive seismic constraints. The full density model and crustal thicknesses from this work are made freely available so that they may be used for further study, for instance as inputs for deformable plate reconstruction modelling.

Modulation Mechanism of Transition Elements Fe and Mn on the Interface Bonding Performance of Bronze/Diamond Composites

The modulation mechanism of iron (Fe) and manganese (Mn) in transition‐metal elements on the interface bonding and mechanical properties of bronze (Cu3Sn)‐based/diamond composites is investigated through first‐principles calculations. Transition‐elements‐doping scenarios are investigated employing six‐layer slab models. It is revealed that the doping of Fe or Mn can make the Cu3Sn/diamond interface more stable, which effectively improves the wettability of the Cu3Sn/diamond interface based on the calculation results and analysis of interface energy, differential charge density model, and density of states. However, co‐doping with both Fe and Mn weakens the wettability of the Cu3Sn/diamond interface. Finally, wettability tests and microstructure characterizations demonstrate that the doping of Fe and Mn represents an effective approach to controlling the interface bonding performance of bronze/diamond composites.

Spright: a probabilistic mass–density–radius relation for small planets

ABSTRACT We present spright, a python package that implements a fast and lightweight mass–density–radius relation for small planets. The relation represents the joint planetary radius and bulk density probability distribution as a mean posterior predictive distribution of an analytical three-component mixture model. The analytical model, in turn, represents the probability for the planetary bulk density as three generalized Student’s t-distributions with radius-dependent weights and means based on theoretical composition models. The approach is based on Bayesian inference and aims to overcome the rigidity of simple parametric mass–radius relations and the danger of overfitting of non-parametric mass–radius relations. The package includes a set of pre-trained and ready-to-use relations based on two M-dwarf catalogues, one catalogue containing stars of spectral types F, G, and K (FGK stars), and two theoretical composition models for water-rich planets. The inference of new models is easy and fast, and the package includes a command line tool that allows for coding-free use of the relation, including the creation of publication-quality plots. Additionally, we study whether the current mass and radius observations of small exoplanets support the presence of a population of water-rich planets positioned between rocky planets and sub-Neptunes. The study is based on Bayesian model comparison and shows somewhat strong support against the existence of a water-world population around M dwarfs. However, the results of the study depend on the chosen theoretical water-world density model. A more conclusive result requires a larger sample of precisely characterized planets and community consensus on a realistic water-world interior structure and atmospheric composition model.

Learning Kernel Stein Discrepancy for Training Energy-Based Models

The primary challenge in unsupervised learning is training unnormalized density models and then generating similar samples. Few traditional unnormalized models know what the quality of the trained model is, as most models are evaluated by downstream tasks and often involve complex sampling processes. Kernel Stein Discrepancy (KSD), a goodness-of-fit test method, can measure the discrepancy between the generated samples and the theoretical distribution; therefore, it can be employed to measure the quality of trained models. We first demonstrate that, under certain constraints, KSD is equal to Maximum Mean Discrepancy (MMD), a two-sample test method. PT KSD GAN (Kernel Stein Discrepancy Generative Adversarial Network with a Pulling-Away Term) is produced to compel generated samples to approximate the theoretical distribution. The generator, functioning as an implicit generative model, employs KSD as loss to avoid tedious sampling processes. In contrast, the discriminator is trained to identify the data manifold, also known as an explicit energy-based model. To demonstrate the effectiveness of our approach, we undertook experiments on two-dimensional toy datasets. Our results highlight that our generator adeptly captures the accurate density distribution, while the discriminator proficiently recognizes the unnormalized approximate distribution shape. When applied to linear Independent Component Analysis datasets, the log likelihoods of PT KSD GAN improve by about 5‰ over existing methods when the data dimension is less than 30. Furthermore, our tests on image datasets reveal that the PT KSD GAN excels in navigating high-dimensional challenges, yielding authentically genuine samples.

Development of low carbon engineered cementitious composite (ECC) using nano lime calcined clay cement (nLC3) based matrix

The construction industry is responsible for around 5% of total CO2 emissions globally. As a result, recent research is focused on the sustainability aspects of construction materials. Engineered cementitious Composites (ECC) are high-performance fiber reinforced composites with improved ductility and tensile strength but utilize higher cement content, raising concerns about their sustainability. In this study, nano-lime and calcined clay are combined with cement to develop a high strength sustainable nano lime calcined clay cement (nLC3) based Engineered Cementitious Composite (ECC). Initially, the packing density model was employed to develop a high strength nLC3-based matrix by combining the particle packing models and chemical compatibility while keeping costs to a minimum. Micromechanical modeling was then applied to determine the critical volume of fibers for the novel matrix using single fiber pullout tests and matrix toughness tests. According to the micromechanical model, the critical volume fraction is found to be 1.93% for the nLC3 mix. This was further confirmed by casting dog bone samples containing 2% fibers by volume which confirmed strain hardening response. The uniaxial test results indicated a strength of around 5.85 MPa in tension and 51 MPa in compression with about 3% tensile strain. These results are comparable to conventional ECC and better than previously developed LC3 based ECC. This study reveals that nLC3-based ECC is a more sustainable composite as compared to conventional ECC mix without any compromise on strength and cost.

Comparison of the operation safety and biomechanical stability of sacral alar-iliac vs. sacroiliac screws in the fixation of sacroiliac joint in simulated models of low bone density

BackgroundSacral alar-iliac screws (SAISs) have been used for sacroiliac joint and are superiority to traditional sacroiliac screws (SISs) in patients with low bone density. The aim of this study was to investigate the operation safety and biomechanical stability of the SIS, transsacral-transiliac screw (TSTIS), S1AIS and S2AIS in the treatment of sacroiliac joint in simulated models of low bone density. MethodsCT data from 80 normal pelvic structures were employed to measure the anatomical parameters, including the safety zones of the S1AIS and S2AIS at the insertion point and the trajectory lengths of the SIS, TSTIS, S1AIS and S2AIS. Sixteen synthetic pelvises with simulated osteoporotic bone structure were used to simulate type C Tile lesions and divided into 4 groups with an anterior plate and posterior fixation using one of the following: 1) one SIS on each side, 2) one TSTIS fixing both sides, 3) one S1AIS on each side, or 4) one S2AIS on each side. The stiffness and maximum load of the specimens were analyzed using a biomechanical machine under vertical loading. ResultsThe safety zone of S1AIS was larger than that of S2AIS (p < 0.05). The TSTIS had the largest trajectory length, followed by the S1AIS and S2AIS, and the SIS had the smallest trajectory length (p < 0.05). However, the lengths of the TSTIS (26.1 ± 1.7 mm) and SIS (27.8 ± 1.8 mm) trajectories on the short side (the iliac side) were smaller than those of S1AIS (40.4 ± 3.8 mm) and S2AIS (39.1 ± 3.8 mm), thus indicating significant differences (p < 0.05). The stiffness and maximum load of S1AIS and S2AIS were similar and the greatest, followed by TSTIS and SIS (p < 0.05). ConclusionThe stability of S1AIS and S2AIS is similar, both stronger than that of SIS and TSTIS, which have shorter lengths of the screw trajectories on the ilium side. However, the safety zone of S2AIS at the insertion point is smaller than that of S1AIS. Therefore, considering both safety and stability, S1AIS is the preferred choice for fixation of sacroiliac joint dislocation in simulated models of low bone density.

Incremental value of physiological indices to predict high-risk plaque detected by NIRS-IVUS

Abstract Background The vulnerable plaque are called high-risk plaques (HRPs), and coronary computed tomography angiography (CCTA) studies have revealed the following characteristics: (1) lesion plaque density on CT≦30HU (2) positive remodeling, (3) The presence of spotty calcification, (4) ΔFractional Flow Reserve derived from CCTA (FFRCT) or Δ Quantitative Flow Reserve (QFR)≧0.06 has been cited as a feature of these lesions. Therefore, identification of HRPs in non-culprit lesion is important to reduce future cardiovascular events. Purpose The purpose of the study was to determine whether HRP is predictable by incremental values of physiological indices in non-culprit lesions of ACS subjects. Methods A total of 137 non-culprit coronary lesions in 31 ACS subjects were retrospectively evaluated by CCTA, FFRCT, QFR and NIRS-IVUS imaging. Each coronary artery was divided into 30mm long segments beginning at the ostium to evaluate lesion vulnerability. By NIRS imaging, plaque with 4-mm maximum lipid-core burden index (maxLCBI4mm) ≥400 was defined as HRP. The relationship between HRP detected by NIRS and CCTA-derived plaque features, delta (Δ) FFRCT, and ΔQFR was evaluated. Results CT density, positive remodeling, diameter stenosis, ΔFFRCT, and ΔQFR were significantly associated with HRP, respectively (P&amp;lt;0.05). On multivariable analysis, CT density (OR; 0.95, 95%CI 0.91-0.99, P=0.0001), diameter stenosis (OR; 1.05, 95%CI 1.00-1.10, P=0.03) and ΔQFR (OR; 2119483 , 95%CI 1.75-2561856632475.6, P=0.03) independently predicted HRP, but not ΔFFRCT. ROC analysis for predicting HRP showed greater accuracy with incremental ΔQFR values in the model of CT density and diameter stenosis (AUC 0.93, P&amp;lt;0.0001). Conclusion HRP detected by NIRS may be predicted with greater accuracy by integrating QFR values with the assessment of CCTA-derived plaque features.figure1figure2

A comparative analysis of using cage acrossing the vertebral ring apophysis in normal and osteoporotic models under endplate injury: a finite element analysis.

Background: Lateral lumbar fusion is an advanced, minimally invasive treatment for degenerative lumbar diseases. It involves different cage designs, primarily varying in size. This study aims to investigate the biomechanics of the long cage spanning the ring apophysis in both normal and osteoporotic models, considering endplate damage, using finite element analysis. Methods: Model 1 was an intact endplate with a long cage spanning the ring apophysis. Model 2 was an endplate decortication with a long cage spanning the ring apophysis. Model 3 was an intact endplate with a short cage. Model 4 was an endplate decortication with a short cage. On the basis of the four original models, further osteoporosis models were created, yielding a total of eight finite element models. The provided passage delineates a study that elucidates the utilization of finite element analysis as a methodology to simulate and analyze the biomechanical repercussions ensuing from the adoption of two distinct types of intervertebral fusion devices (cages) within the physiological framework of a human body. Results: The investigation found no appreciable changes between Models 1 and 2 in the range of motion at the fixed and neighboring segments, the L3-4 IDP, screw-rod stress, endplate stress, or stress on the trabecular bone of the L5. Increases in these stresses were seen in models 3 and 4 in the ranges of 0.4%-676.1%, 252.9%-526.9%, 27.3%-516.6%, and 11.4%-109.3%, respectively. The osteoporotic models for scenarios 3 and 4 exhibit a similar trend to their respective normal bone density models, but these osteoporotic models consistently have higher numerical values. In particular, except for L3-4 IDP, the maximum values of these parameters in osteoporotic Models 3 and 4 were much higher than those in normal bone quality Models 1 and 2, rising by 385.3%, 116%, 435.1%, 758.3%, and 786.1%, respectively. Conclusion: Regardless of endplate injury or osteoporosis, it is advised to utilize a long cage that is 5mm longer on each side than the bilateral pedicles because it has good biomechanical features and may lower the likelihood of problems after surgery. Additionally, using Long cages in individuals with osteoporosis may help avoid adjacent segment disease.

Measurement of neutron induced reaction cross-section of 99Mo

In the present work, we have measured 98Mo(n,γ)99Mo reaction cross-section using a 7Li(p,n)7Be neutron source at 1.67 ± 0.14, 2.06 ± 0.14 and 2.66 ± 0.16 MeV neutron energies. We have employed offline γ-ray spectroscopy to measure the induced activity of the sample. The 115In(n,n’γ)115mIn reaction was used as a monitor reaction. Different attributes propagating the uncertainty in the total result, measured cross-sections with their uncertainties and correlation coefficients are given in detail in the present study. The result is compared with the data libraries, EXFOR database and theoretical model outcome from different level density models.

Analysis of the Impact of Atmospheric Models on the Orbit Prediction of Space Debris

Atmospheric drag is an important influencing factor in precise orbit determination and the prediction of low-orbit space debris. It has received widespread attention. Currently, calculating atmospheric drag mainly relies on different atmospheric density models. This experiment was designed to explore the impact of different atmospheric density models on the orbit prediction of space debris. In the experiment, satellite laser ranging data published by the ILRS (International Laser Ranging Service) were used as the basis for the precise orbit determination for space debris. The prediction error of space debris orbits at different orbital heights using different atmospheric density models was used as a criterion to evaluate the impact of atmospheric density models on the determination of space-target orbits. Eight atmospheric density models, DTM78, DTM94, DTM2000, J71, RJ71, JB2006, MSIS86, and NRLMSISE00, were compared in the experiment. The experimental results indicated that the DTM2000 atmospheric density model is best for determining and predicting the orbits of LEO (low-Earth-orbit) targets.

Computation of medical radioisotopes cross section using level density models

The cross section is an important parameter in nuclear science it is obtained using different models in theoretical calculation way. Level density is one of the key input components for calculating the reaction cross sections in particular. In this study, the cross sections have been calculated using level density models on some medical radioisotopes. The calculation were performed using TALYS 1.95 computer program and the obtained data were compared with the available experimental data and the effect of level density models on 12C, 16O, 14N, 28Si, 63Cu, 90Zr, 197Au, 107Ag, 186W radionuclides have been investigated. It is clear that GSM level density models generally give conclusions that are harmonious with existing experimental data.

Digital model of the drag force of the Earth’s upper atmosphere for the design of low-orbit spacecraft

A digital model is described for estimating the drag force of the Earth's upper atmosphere acting on a low-orbit spacecraft. Unlike the classical model of aerodynamic force, the digital model is the result of a computer algorithm. This algorithm calculates the field of aerodynamic force values, taking into account changes in the flight altitude, aerodynamic coefficient and the area of the spacecraft midsection over time. The calculations also use a digital model of the dynamic density of the Earth's upper atmosphere. The digital model of the drag force of the Earth's upper atmosphere is useful in the design of low-orbit spacecraft with a low-thrust jet propulsion system (thrust order – millinewtons). On the basis of the calculated values of the aerodynamic force, it is possible to form requirements for the geometry of the spacecraft, attitude modes and arrangement of low-thrust jet engines (for example, electric jet engines). With the accumulation of big data in the form of tabular functions of aerodynamic force from the space of various design and ballistic parameters of low-orbit spacecraft, it is possible to create a machine model (ML-model). It will make forecasts of the values of the design characteristics for the low-orbit spacecraft being developed according to a limited set of initial requirements.

Response retention and apparent motion effect in visual cortex models.

Apparent motion is a visual illusion in which stationary stimuli, flashing in distinct spatial locations at certain time intervals, are perceived as one stimulus moving between these locations. In the primary visual cortex, apparent-motion stimuli produce smooth spatio-temporal patterns of activity similar to those produced by continuously moving stimuli. An important prerequisite for producing such activity patterns is prolongation of responses to brief stimuli. Indeed, a brief stimulus can evoke in the visual cortex a long response, outlasting the stimulus by hundreds of milliseconds. Here we use firing-rate based models with simple ring structure, and biologically-detailed conductance-based refractory density (CBRD) model with retinotopic space representation to analyze the response retention and the origin of smooth profiles of activity in response to apparent-motion stimuli. We show that the strength of recurrent connectivity is the major factor that endorses neuronal networks with the ability for response retention. The same strengths of recurrent connections mediate the appearance of bump attractor in the ring models. Factors such as synaptic depression, NMDA receptor mediated currents, and conductances regulating spike adaptation influence response retention, but cannot substitute for the weakness of recurrent connections to reproduce response retention in models with weak connectivity. However, the weakness of lateral recurrent connections can be compensated by layering: in multi-layer models even with weaker connections the activity retains due to its feedforward propagation from layer to layer. Using CBRD model with retinotopic space representation we further show that smooth spatio-temporal profiles of activity in response to apparent-motion stimuli are produced in the models expressing response retention, but not in the models that fail to produce response retention. Together, these results demonstrate a link between response retention and the ability of neuronal networks to generate spatio-temporal patterns of activity, which are compatible with perception of apparent motion.

A heliospheric density and magnetic field model

Context. The radial evolution of the density of the plasma and the magnetic field in the heliosphere, especially in the region between the solar corona and the Earth’s orbit, has been a topic of active research for several decades. Both remote-sensing observations and in situ measurements by spacecraft such as HELIOS, Ulysses, and WIND have provided critical data on this subject. The NASA space mission Parker Solar Probe (PSP), which will approach the Sun down to a distance of 9.9 solar radii on December 24, 2024, gives new insights into the structure of the plasma density and magnetic field in the heliosphere, especially in the near-Sun interplanetary space. This region is of particular interest because the launch and evolution of coronal mass ejections (CMEs), which can influence the environment of our Earth (usually called space weather), takes place there. Aims. Because of the new data from PSP, it is time to revisit the subject of the radial evolution of the plasma density and magnetic field in the heliosphere. To do this, we derive a radial heliospheric density and magnetic field model in the vicinity of the ecliptic plane above quiet equatorial regions. The model agrees well with the measurements in the sense of a global long-term average. Methods. The radial evolution of the density and solar wind velocity is described in terms of Parker’s wind equation. A special solution of this equation includes two integration constants that are fitted by the measurements. For the magnetic field, we employed a previous model in which the magnetic field is describe by a superposition of the magnetic fields of a dipole and a quadrupole of the quiet Sun and a current sheet in the heliosphere. Results. We find the radial evolution of the electron and proton number density as well as the radial component of the magnetic field and the total field strength in the heliosphere from the bottom of the corona up to a heliocentric distance of 250 solar radii. The modelled values are consistent with coronal observations, measurements at 1 AU, and with the recent data from the inner heliosphere provided by PSP. Conclusions. With the knowledge of the radial evolution of the plasma density and the magnetic field in the heliosphere the radial behaviour of the local Alfvén speed can be calculated. It can can reach a local maximum of 392 km s−1 at a distance of approximately 4 solar radii, and it exceeds the local solar wind speed at distances in the range of 3.6−13.7 solar radii from the centre of the Sun.

Modeling and Experimental Study of Packing Density of Foam Glass Concrete

The paper deals with the process of production and properties of foam glass concrete – a composite material consisting of modified gypsum binder and granulated foam glass as an aggregate. Foam glass concrete has high strength, durability, environmental friendliness and low thermal conductivity, which makes it a promising material for wall structures. Optimal packing densities were obtained by using programs developed by the authors in the Python programming language to calculate the optimal diameters of three fractions of granular foam glass in an orthogonal or hexagonal packing model. The compressive and flexural strength and thermal conductivity coefficient were investigated on samples of different compositions. The value of the thermal conductivity coefficient of the foam glass concrete was reduced due to the air-entraining additive. In conclusion, the optimum composition of foam glass concrete was proposed taking into account all investigated parameters.

Simulations of Io Plasma Torus Around Jupiter: Predictions for Lenghu Observatory

AbstractCharacterizing the temporal evolution of the three‐dimensional structure of the Io plasma torus is essential to understand the dynamics of the Jovian magnetosphere. Optical imaging is a powerful tool to uncover the global torus structure. Currently, two ground‐based optical telescopes with diameters of 0.8 and 1.8 m, respectively, are under construction at the Lenghu Observatory for Planetary Science on the Tibetan Plateau of China, to systematically observe the Io plasma torus at wavelengths between 392 and 1,100 nm. These telescopes will begin to operate in the end of 2023. In order to support the inversion and scientific interpretation of the Io plasma torus images, we perform systematic simulations of the Io plasma torus in this work. First, a three‐dimensional model of electron and ion densities and electron temperature is constructed first. Then, the emissions of O+ 372.7 nm, O+ 372.9 nm, S+ 406.9 nm, S+ 671.8 nm, S+ 673.1 nm, and S++ 953.2 nm are simulated from the perspective of observing from the Earth. The simulated emission intensities and distributions are consistent with previous observations. This work provides a state‐of‐the‐art convenient tool for ground‐based telescope observation of the Io plasma torus at a specific site and time and also benefits future inversion of images to obtain physical parameters of Io plasma torus.