Model Of Formation Research Articles

Numerical Modeling and Experimental Validation of Icing Phenomena on the External Surface of a U-Bend Tube

The regasification of liquefied natural gas (LNG) is a crucial process that involves certain challenges created by the low temperature of LNG and the risk of ice formation on the external surfaces of the tubes of heat exchangers, which can hinder heat transfer and increase flow resistance. This study presents a numerical model for ice formation on the external surface of the U-bend tube of shell-and-tube heat exchangers. The numerical model has been further enhanced by applying a custom user-defined function. The numerical results were validated using experimental data and demonstrated excellent predictive capability, particularly for the surface temperature of the tubes and the thickness of the ice layer. Hence, this model can reliably capture the overall behavior of the ice formation on the external surfaces of the tubes of shell-and-tube heat exchangers. By highlighting the importance of maintaining stable heat transfer conditions to prevent freezing, this study offers valuable insights that can guide the optimization of heat exchanger designs for LNG regasification.

Formative Models of Vietnamese Diplomatic Terminology

Formative Models of Vietnamese Diplomatic Terminology

Triple trouble with PSR J1618−3921: Mass measurements and orbital dynamics of an eccentric millisecond pulsar

Context. PSR J1618−3921 is one of five known millisecond pulsars (MSPs) in eccentric orbits (eMPSs) located in the Galactic plane, whose formation is poorly understood. Earlier studies of these objects revealed significant discrepancies between observations and predictions from standard binary evolution scenarios of pulsar-helium white dwarf (HeWD) binaries, especially in the case of PSR J0955−6150, for which mass measurements ruled out most eMSP formation models. Aims. We aim to measure the masses of the pulsar and its companion, and constrain the orbital configuration of PSR J1618−3921. This facilitates understanding similarities among eMSPs and could offer hints as to their formation mechanism. Methods. We conducted observations with the L-band receiver of the MeerKAT radio telescope and the UWL receiver of the Parkes Murriyang radio telescope between 2019 and 2021. These data were added to archival Parkes and Nançay observations. We performed a full analysis on this joint data set with a timing baseline of 23 years. We also used the data from recent observations to give a brief account of the emission properties of J1618−3921, including a rotating vector model (RVM) fit of the linear polarisation position angle of the pulsar. Results. From the timing analysis, we measure a small but significant proper motion of the pulsar. The long timing baseline allowed for a highly significant measurement of the rate of advance of periastron of ω̇ = (0.00145±0.00010)°yr−1. Despite the tenfold improvement in timing precision from MeerKAT observations, we can only report a low-significance detection of the orthometric Shapiro delay parameters, h3 = 2.70−1.47+2.07 μs and ς = 0.68−0.09+0.13. Under the assumption of the validity of general relativity (GR), the self-consistent combination of these three parameters leads to mass estimates of the total and individual masses in the binary of Mtot = 1.42−0.19+0.20 M⊙, Mc = 0.20−0.03+0.11 M⊙, and Mp = 1.20−0.20+0.19 M⊙. We detect an unexpected change in the orbital period of Ṗb = −2.26−0.33+0.35 × 10−12, that is an order of magnitude larger and carries an opposite sign to what is expected from the Galactic acceleration and the Shklovskii effect, which are a priori the only non-negligible contributions expected for Ṗb. We also detect a significant second derivative of the spin frequency, f̈. The RVM fit reveals a viewing angle of ζ = (111 ± 1)°. Furthermore, we report an unexpected, abrupt change in the mean pulse profile in June 2021 of unknown origin. Conclusions. We propose that the anomalous Ṗb and f̈ we measure for J1618−3921 indicate an additional varying acceleration due to a nearby mass. The J1618−3921 binary system is likely part of a hierarchical triple, but with the third component much farther away than the outer component of the MSP in a triple star system, PSR J0337+1715. This finding suggests that at least some eMSPs might have formed in triple star systems. Although the uncertainties are large, the binary companion mass is consistent with the Pb − MWD relation, which has been verified for circular HeWD binaries and also for the two HeWDs in the PSR J0337+1715 system. Future regular observations with the MeerKAT telescope will, due to the further extension of the timing baseline, improve the measurement of Ṗb and f̈. This will help us further understand the nature of this system, and perhaps improve our understanding of eMSPs in general.

Agent-based modeling system for real-time characterization of film thickness in digital twin coating

In the automated spraying workshop of ship segments, poor visibility caused by dust and fog hampers the effectiveness of the video monitoring system. The traditional method used during the automated spraying process fails to provide real-time measurement of film thickness and prediction of spraying quality, resulting in uneven film thickness and high rework rates. Robotic spraying technology also faces challenges, such as the time-consuming and labor-intensive process of building and computing a highly reliable Computational Fluid Dynamics (CFD) based spraying film-forming simulation model, which cannot be reflected in real-time during the spraying process. The digital twin characterization method, based on the agent model, offers a solution to these limitations and challenges, providing new ideas and approaches for improving and optimizing the spray film formation model. This paper presents the development of a real-time characterization system for sprayed film thickness based on digital twin technology. The spraying film thickness under different working conditions is obtained using Ansys-Fluent simulation software by varying the gun height and gun speed. The predictive model for spraying film thickness is then established using the obtained simulation data and the corresponding gun height and gun speed, employing the surrogate modeling method (BP neural network). The real-time characterization system for spraying film thickness is developed by combining C# and Unity3D. Finally, in order to ensure the accuracy of the predictive model, a spraying experimental platform is built to verify the accuracy of the predictive model.

Young Europeans’ Geo-Political Identities: A Poststructural Analysis

This study analyses the way young Europeans, aged between 10 and 20, construct their sense of identity with geo-political entities such as the nation, the state and the European Union; how these are expressed; and how young people manage the potential multiplicity of identities. It re-analyses earlier data, some 224 transcripts of young Europeans discussing their identities and sense of attachment to the geo-political entities of the state and the nation. This study looks specifically at how they discuss affiliations to a country or nation and does so within the historical context of the development of European nations in the 19th and 20th centuries and the ‘strict definition’ of nationality, as based on either birthplace or parentage. The young people’s discussions identify a wide range of reasons for attachment (or not) to one or more states: these include parentage, birthplace, passports, culture, language, residence, etc., many of which are incompatible with each other. Their response to this is often to profess multiple identities, switching to use that is most appropriate to a particular context or contingency. How does this behaviour meet the various models of identity formation, such as the psychosocial, the socio-cultural, and the poststructuralist? These young people also offer a range of qualities or values that they expect a state to uphold and deliver and are sometimes critical of states’ behaviour in this area. The combination of these attributes and qualities leads to a range of attitudes towards a polity or polities, ranging from acceptance of their status to indifference. The explanations suggested in this paper are that globalisation and migration have led to the realisation that the ‘strict definitions’ of nationality are no longer appropriate, and there are new potential attributes for identity, and secondly, that the development of supranational codification and the implementation of human rights are weakening the sovereignty of states. Together, these two factors reduce the perception of the requirement to develop a single overriding national identity. This combination of multiple identities and recognising the importance of human rights values is most commonly found amongst young people who have grown up in multicultural societies, often urban, and the corollary of this is that combination is least likely to be found among the older population in more rural, monocultural settlements.

Modelling of planetary accretion and core-mantle structure formation

Abstract We advance a thermodynamically consistent model of self-gravitational accretion and differentiation in planets. The system is modeled in actual variables as a compressible thermoviscoelastic fluid in a fixed, sufficiently large domain. The supply of material to the accreting and differentiating system is described as a bulk source of mass, volume, impulse, and energy localized in some border region of the domain. Mass, momentum, and energy conservation, along with constitutive relations, result in an extended compressible Navier–Stokes-Fourier-Poisson system. The centrifugal and Coriolis forces are also considered. After studying some single-component setting, we consider a two-component situation, where metals and silicates mix and differentiate under gravity, eventually forming a core-mantle structure. The energetics of the models are elucidated. Moreover, we prove that the models are stable, in that self-gravitational collapse is excluded. Eventually, we comment on the prospects of devising a rigorous mathematical approximation and existence theory.

Understanding Relaxation in the Kob-Andersen Liquid Based on Entropy, String, Shoving, Localization, and Parabolic Models.

We assess the validity of a range of models of glass formation based on molecular dynamics simulation results of the Kob-Andersen (KA) model system under a wide range of constant volume and constant pressure conditions. These models include the Adam-Gibbs model emphasizing configurational entropy, the string model emphasizing collective particle exchange motion, the shoving model emphasizing material elasticity, the localization model emphasizing dynamical free volume, and parabolic models based on the ideas of dynamic facilitation and, alternatively, the hypothesis that glass formation involves an avoided critical point. We demonstrate that these seemingly disparate models all provide a reasonable description of structural relaxation and diffusion data for the KA model system under all simulation conditions considered. Hence, the present study points to some unity in our understanding of the relationship between leading models of glass formation, supporting inferences drawn from previous studies of polymeric glass-forming liquids.

Fourier phase retrieval using physics-enhanced deep learning

Fourier phase retrieval (FPR) aims to reconstruct an object image from the magnitude of its Fourier transform. Despite its widespread utility in various fields of engineering and science, the inherent ill-posed nature of the FPR problem poses a significant challenge. Here we propose a learning-based approach that incorporates the physical model of the FPR imaging system with a deep neural network. Our method includes two steps: First, we leverage the image formation model of the FPR to guide the generation of data for network training in a self-supervised manner. Second, we exploit the physical model to fine-tune the pre-trained model to impose the physics-consistency constraint on the network prediction. This allows us to integrate both implicit prior from training data and explicit prior from the physics of the imaging system to address the FPR problem. Simulation and experiments demonstrate that the proposed method is accurate and stable, showcasing its potential for wide application in fields utilizing the FPR. We have made our source code available for non-commercial use.

Differences in elemental abundances between CI chondrites and the solar photosphere

AbstractCI chondrites have been a proxy for the solar system since the mid‐20th century. The photospheric and CI chondrite abundances (P and CI, respectively) show a strong correlation. CI as a proxy is also justified by the (i) smoothness of their abundances plotted as a function of odd mass number and (ii) agreement within the error of P as determined spectroscopically. But our statistical assessment of spectroscopic studies and solar wind from the Genesis mission indicates that the small, ~10%–30%, differences (residuals) between CI and P depend on the 50% condensation temperature (Tc50). So, if CI is to be used as a proxy for P, Cosmochemists may want to add a correction to individual elements. Our work is consistent with two published hypotheses: that (i) residuals are linear with Tc50 and (ii) that elements having Tc50 > 1343 K are depleted relative to those with 495 K < Tc50 < 1343 K in CI. We discuss other interpretations which are also feasible. Understanding these small differences of the CI and P for different elements and their variation with Tc50 can help constrain future models of solar system formation and the history of CI chondrites.

Dust in Little Red Dots

JWST has revealed a ubiquitous population of “little red dots” (LRDs) at z ≳ 4, selected via their red rest-frame optical emission and compact morphologies. They are thought to be reddened by dust, whether in tori of active galactic nuclei (AGNs) or the interstellar medium, though none have direct dust detections to date. Informed by the average characteristics of 675 LRDs drawn from the literature, we provide ballpark constraints on the dust characteristics of the LRD population and estimate they have average dust masses of 〈Mdust〉=(1.6−0.9+4.8)×104 M ⊙, luminosities of 〈LIR〉=(8−5+3)×1010 L ⊙, and temperatures of 〈Tdust〉=110−36+21 K. Notably, the spectral energy distributions are thought to peak at ∼100 K (rest-frame 20–30 μm) regardless of heating mechanism, whether AGN or star formation. LRDs’ compact sizes R eff ∼ 100 pc are the dominant factor contributing to their low estimated dust masses. Our predictions likely mean LRDs have, on average, a submillimeter emission factor of ∼100× fainter than current Atacama Large Millimeter/submillimeter Array limits provide. The star-to-dust ratio is a factor ∼100× larger than expected from dust formation models if one assumes the rest-optical light is dominated by stars; this suggests stars do not dominate. Despite their high apparent volume density, LRDs contribute negligibly (0.1%) to the cosmic dust budget at z ≳ 4 due to their low dust masses.

Accretion and Core Formation of Earth-like Planets: Insights from Metal–Silicate Partitioning of Siderophile and Volatile Elements

The origin of volatile elements, the timing of their accretion and their distribution during Earth’s differentiation are fundamental aspects of Earth’s early evolution. Here, we present the result of a newly developed accretion and core formation model, which features the results of high P–T metal–silicate partitioning experiments. The model includes well-studied reference elements (Fe, Ni, Ca, Al, Mg, Si) as well as trace elements (V, Ga, Ag, Au, S) covering a wide range from refractory to volatile behavior. The accretion model simulates the different steps of planet formation, such as the effects of continuous, heterogenous core formation at high P–T, the effect of the Moon-forming giant impact and the addition of matter after the core formation was completed, the so-called “late veneer”. To explore the “core formation signature” of the volatile depletion patterns and the quantitative influence of a late veneer, we modeled planets that would have formed from known materials, such as CI, CM, CV, CO, EH and EL meteorites, and from a hypothetical volatile depleted material, CI*. Some of the resulting planets are Earth-like in key properties, such as overall core size, major element composition, oxygen fugacity and trace element composition. The model predicts the chemical signatures of the main planetary reservoirs, the metallic core and bulk silicate planet (BSP) of the modeled planets, which we compare with the chemical signature of Earth derived previously from core formation models and mass balance-based approaches. We show that planets accreted from volatile depleted carbonaceous chondrites (CM, CV, CO and CI*) are closest in terms of major element (Si, Mg, Fe, Ca, Al, Ni) and also siderophile volatile element (Ge, Ga, Au) concentrations to the components from which Earth accreted. Chalcophile volatile elements (S, Ag), instead, require an additional process to lower their concentrations in the BSP to Earth-like concentrations, perhaps the late segregation of a sulfide melt.

Navigating linguistic ideologies and market dynamics within China’s English language teaching landscape

Abstract This study explores the intricate interplay of linguistic ideologies, market dynamics, and linguistic habitus within the context of English language education in China. Analysis of Chinese English language teachers’ (CELTs) discourse on linguistic insecurity reveals a strong association between accentedness and incompetence, as well as between nativeness and teacher expertise. Despite dissatisfaction with nativeness-oriented criteria prevalent in the field, most CELTs reported experiencing anxiety due to the social stigma surrounding Mandarin-accented English. While certain Inner Circle English varieties are viewed as the most valuable capital, local and other non-Inner Circle varieties are considered the least valuable. Notably, Mandarin-accented English gains higher symbolic value than other perceived nonstandard English varieties beyond the teaching domain. This pricing mechanism within China’s English language teaching (ELT) landscape deviates from the price formation model of world Englishes proposed in previous work, which assigns a greater value to Outer Circle varieties than Expanding Circle varieties. By contextualizing CELTs’ experiences within broader language policies, this study illustrates how national interests, beyond the influence of Inner Circle publishers, intensify native-speakerism in China’s ELT market, thus emphasizing the intricate nature of explaining nuanced pricing patterns in the autonomous market within Expanding Circle contexts.

ExoLyn: A golden mean approach to multispecies cloud modeling in atmospheric retrieval

Clouds are ubiquitous in exoplanets' atmospheres and play an important role in setting the opacity and chemical inventory of the atmosphere. Understanding clouds is a critical step in interpreting exoplanets' spectroscopic data. The aim is to model the multispecies nature of clouds in atmospheric retrieval studies. To this end, we developed -- a 1D cloud model that balances physical consistency with computational efficiency. solves the transport equation of cloud particles and vapor under cloud condensation rates that are self-consistently calculated from thermodynamics. is a standalone, open source package capable of being combined with optool to calculate solid opacities and with petitRADTRANS to generate transmission or emission spectra. With we find that the compositional structure of clouds in hot Jupiter planets' atmospheres is layered with a cloud dominated by magnesiumsilicates on top of an iron cloud. This finding is consistent with more complex cloud formation models but can be obtained with in only a few seconds. The composition of the cloud particles can be constrained from the spectrum, for example MgSiO3 and Mg2SiO4 components give rise to an absorption feature at $8-10\ m $. We investigate the dependence of the cloud structure on the bulk elemental composition of the planet and find that SiO2 -dominated clouds form on metal-rich planets and Fe clouds with a strong extinction effect form on C-rich planets. Designed toward maximum flexibility can also be used in retrieval analysis of sub-Neptunes and self-luminous planets. The efficiency of opens the possibility of joint retrieval of exoplanets' gas and cloud components.

Viscous shear is a key force in Drosophila ventral furrow morphogenesis.

Ventral furrow (VF) formation in Drosophila melanogaster is an important model of epithelial folding. Previous models of VF formation require cell volume conservation to convert apically localized constriction forces into lateral cell elongation and tissue folding. Here, we investigated embryonic morphogenesis in anillin knockdown (scra RNAi) embryos, where basal cell membranes fail to form and therefore cells can lose cytoplasmic volume through their basal side. Surprisingly, the mesoderm elongation and subsequent folding that comprise VF formation occurred essentially normally. We hypothesized that the effects of viscous shear may be sufficient to drive membrane elongation, providing effective volume conservation, and thus driving tissue folding. Since this hypothesis may not be possible to test experimentally, we turned to a computational approach. To test whether viscous shear is a dominant force for morphogenesis in vivo, we developed a 3D computational model incorporating both accurate cell and tissue geometry and experimentally measured material parameters. Results from this model demonstrate that viscous shear generates sufficient force to drive cell elongation and tissue folding in vivo.

Role of the SaeRS Two-Component Regulatory System in Group B Streptococcus Biofilm Formation on Human Fibrinogen.

Streptococcus agalactiae, also known as Group B Streptococcus or GBS, is a commensal colonizer of human vaginal and gastrointestinal tracts that can also be a deadly pathogen for newborns, pregnant women, and the elderly. The SaeRS two-component regulatory system (TCS) positively regulates the expression of two GBS adhesins genes, but its role in the formation of biofilm, an important step in pathogenesis, has not been investigated. In the present study, we set up a novel model of GBS biofilm formation using surfaces coated with human fibrinogen (hFg). Biofilm mass and structure were analyzed by crystal violet staining and three-dimensional fluorescence microscopy, respectively. GBS growth on hFg resulted in the formation of a mature and abundant biofilm composed of bacterial cells and an extracellular matrix containing polysaccharides, proteins, and extracellular DNA (eDNA). Enzymatic and genetic analysis showed that GBS biofilm formation on hFg is dependent on proteins and eDNA in the extracellular matrix and on the presence of covalently linked cell wall proteins on the bacterial surface but not on the type-specific capsular polysaccharide. In the absence of the SaeR regulator of the SaeRS TCS, there was a significant reduction in biomass formation, with reduced numbers of bacterial cells, reduced eDNA content, and disruption of the biofilm architecture. Overall, our data suggest that GBS binding to hFg contributes to biofilm formation and that the SaeRS TCS plays an important role in this process.

Развитие модели динамики снежного покрова Гидрометцентра России

Conceptual models of runoff formation used in the operational practice of hydrological forecasting by the Hydrometeorological Center of Russia include simplified parameterization of snow cover dynamics based on the use of snow cover melting coefficient, water-retaining capacity of snow and secondary freezing of meltwater in case of return of negative air temperatures. This schematization of the process is well established for the reliable calculation of the snow water equivalent for subsequent use in the calculation of meltwater inflow to the catchment surface and the calculation of streamflow characteristics. At the same time, the lack of calculation of snow density and snow height in the used schematization restricts the use of schemes for calculating of soil freezing depth in hydrological models, which seems to be extremely important for modelling runoff on mid-latitudes rivers, i.e. for the most Russian rivers. To overcome this disadvantage, the snow density and snow height parameterization was added to the calculation scheme of the model, which was verified using Roshydromet’s snow measurement routes data and shown a good and satisfactory quality of modeling of model characteristics.

Prospects of productive strata of the pre-Jurassic complex of Western Siberia for the discovery and involvement in the development

The article discusses the prospects of productive strata of deposits of the pre-Jurassic complex of Western Siberia for searching, forecasting and involving in the development. Some features of the geological structure of Triassic volcanic-sedimentary deposits and formations of the Paleozoic basement have been identified within the pre-Jurassic complex. The construction of digital geological models of Triassic and Paleozoic formations, which are fundamentally different in the geometry of the internal structure of the hydrocarbon deposits discovered in them, is based on 3D seismic information and its interpretation. In deposits of Triassic and Paleozoic sediments, significant differences in the composition and filtration-capacitive properties of rock reservoirs have been recorded; the principles for creating the structural frameworks of their digital models are also different. 3D seismic data makes it possible to correlate the Triassic strata and identify individual cycles, the boundaries and geometry of which are used to create digital three-dimensional geological models. When creating models of hydrocarbon deposits in Paleozoic formations confined to basement high areas, based on the interpretation of 3D seismic survey materials and analysis of seismic attributes, in combination with information on core, petrophysics and well testing, a forecast is made for the development of areas and strata of increased fracturing of rocks, which are the main inflow strata in production wells. Using the example of individual developed deposits confined to the pre-Jurassic complex in the fields of Western Siberia, the actual results of integrating geological and geophysical information with 3D seismic data are shown. Based on these results not only an assessment of the geological reserves of hydrocarbons was carried out, but also hydrodynamic calculations were conducted to perform history matching, as well as recommendations were made for the locations for drilling wells, their geometry and test strata. The accumulated experience in exploration and development of productive deposits of the pre-Jurassic complex allows us to assess the geometry and features of objects of interest in this interval, select the most informative methods for their mapping and methods for creating digital geological models that are the basis for designing the development.

Modelling pressure dynamics of oil–gas two-phase flow in double-porosity media formation with permeability-stress sensitivity

Pressure dynamics can reflect the basic characteristics of fluid flow through underground porous formation. In this research, the oil–gas two-phase flow model for a double-porosity media formation with permeability-stress sensitivity was first established for three kinds of outer boundaries. The unified governing equation was deduced by utilizing the H function. The nonlinear mathematical model in consideration of permeability-stress sensitivity was linearized by implementing the canonical perturbation transformation and then solved by using the Laplace transformation. After that, a sequence of typical log–log curves of pressure dynamics influenced by various model parameters were plotted and analyzed. These curves reflect the typical characteristic of a V shape caused by the inter-porosity fluid flow from matrix toward natural fractures. Oil saturation and permeability-stress sensitivity coefficient have much influence on the pressure dynamics. Ultimately, the established model of oil–gas two-phase flow was validated through a well-test fitting interpretation for a real condensate gas well in a sandstone formation. This research can offer insights into the pressure dynamics dominated by the oil–gas two-phase flow in naturally fractured formations and the permeability-stress sensitivity effect.

Model of formation of tutoring competence of future educational psychologists

The article discusses the problem of individualization of training and substantiates the importance of developing a specialist’s tutoring competence. When designing a model for the formation of tutoring competence of future educational psychologists, the methodological foundations were identified: problem-oriented, systemic and competency-based approaches. The research used methods of systematization, generalization, synthesis and modeling. The blocks of the model are identified (conceptual-target, content, procedural and evaluative-resultative) and their characteristics are given.

Accelerated Aging Effects Observed In Vitro after an Exposure to Gamma-Rays Delivered at Very Low and Continuous Dose-Rate Equivalent to 1-5 Weeks in International Space Station.

Radiation impacting astronauts in their spacecraft come from a "bath" of high-energy rays (0.1-0.5 mGy per mission day) that reaches deep tissues like the heart and bones and a "stochastic rain" of low-energy particles from the shielding and impacting surface tissues like skin and lenses. However, these two components cannot be reproduced on Earth together. The MarsSimulator facility (Toulouse University, France) emits, thanks to a bag containing thorium salts, a continuous exposure of 120 mSv/y, corresponding to that prevailing in the International Space Station (ISS). By using immunofluorescence, we assessed DNA double-strand breaks (DSB) induced by 1-5 weeks exposure in ISS of human tissues evoked above, identified at risk for space exploration. All the tissues tested elicited DSBs that accumulated proportionally to the dose at a tissue-dependent rate (about 40 DSB/Gy for skin, 3 times more for lens). For the lens, bones, and radiosensitive skin cells tested, perinuclear localization of phosphorylated forms of ataxia telangiectasia mutated protein (pATM) was observed during the 1st to 3rd week of exposure. Since pATM crowns were shown to reflect accelerated aging, these findings suggest that a low dose rate of 120 mSv/y may accelerate the senescence process of the tested tissues. A mathematical model of pATM crown formation and disappearance has been proposed. Further investigations are needed to document these results in order to better evaluate the risks related to space exploration.