Redistribution Model Research Articles

Investigation on the quench characteristics of parallel high temperature superconducting tapes

Abstract The thermal load on high-temperature superconducting (HTS) tapes during quenching poses a threat to the stable operation of superconducting magnets. To protect superconducting coils and cables, this paper investigates the quench characteristics of HTS tapes as a basis. First, coupled with a reduced-dimensional thermal model and current redistribution model, a finite element method (FEM) model based on the 3D T-A formulation for a single HTS tape was built. Taking into account the terminal resistances and circuit inductances, the quench characteristics of parallel HTS tapes can be further analyzed by the field-circuit model. Then, a platform for detecting local quenches was constructed to verify the simulation results, and the experimental procedure was explained in detail, along with the test samples. Finally, we present the quench characteristics of single HTS tape, parallel HTS tapes, and stacked HTS tapes, which were found to be consistent with the simulation results. The parallel structure significantly reduces the risk of local quench compared to a single HTS tape. Due to contact resistances, the quench time of parallel tapes is longer than stacked tapes.

Phase-resolved Hubble Space Telescope WFC3 Spectroscopy of the Weakly Irradiated Brown Dwarf GD 1400 and Energy Redistribution–Irradiation Trends in Six White Dwarf–Brown Dwarf Binaries

Abstract Irradiated brown dwarfs offer a unique opportunity to bridge the gap between stellar and planetary atmospheres. We present high-quality Hubble Space Telescope/Wide Field Camera 3/G141 phase-resolved spectra of the white dwarf–brown dwarf binary GD 1400, covering more than one full rotation of the brown dwarf. Accounting for brightness variations caused by ZZ Ceti pulsations, we revealed weak (∼1%) phase-curve amplitude modulations originating from the brown dwarf. Subband light-curve exploration in various bands showed no significant wavelength dependence on amplitude or phase shift. Extracted day- and nightside spectra indicated chemically similar hemispheres, with slightly higher dayside temperatures, suggesting efficient heat redistribution or the dominance of radiative escape over atmospheric circulation. A simple radiative and energy redistribution model reproduced the observed temperatures well. Cloud-inclusive models fit the day and night spectra better than cloudless models, indicating global cloud coverage. We also begin qualitatively exploring atmospheric trends across six irradiated brown dwarfs, from the now complete “Dancing with the Dwarfs” white dwarf–brown dwarf sample. The trend we find in the dayside/nightside temperature and irradiation levels is consistent with efficient heat redistribution for irradiation levels less than ∼109 erg s−1 cm−2 and decreasing efficiency above that level.

Resilience assessment of urban rail transit stations considering disturbance and time‐varying passenger flow

AbstractUnlike most urban rail transit (URT) resilience studies on URT lines or networks under major disturbances, this paper focuses on the resilience assessment of URT stations under high‐frequency daily disturbances with minor impacts. A resilience assessment metric with different resilience levels is proposed, which is calculated based on multiple criteria, including the number of delayed passengers, degree of congestion, economic loss from service suppliers’ perspective, extra in‐station travel time, extra walking distance, and extra waiting time from passengers’ perspective. A two‐stage passenger flow redistribution model is developed with stage one focusing on route adjustment under disturbance, while stage two determining the walking path within the disrupted station. A case study of Simaqiao Station in the Chengdu subway network in China is conducted. The numerical results indicate that this station demonstrates strong resilience in most scenarios, although it faces challenges under certain identified disturbances.

The Impact of the Angle-average Approximation in the Partial Frequency Redistribution Modeling of the Mg ii h–k Doublet Stokes Profiles

Abstract In recent years, the Mg ii h and k lines have become increasingly important for the diagnostics of magnetic fields in the solar chromosphere, motivated both by the advances in the modeling capabilities of their polarization and by the unprecedented spectropolarimetric observations provided by the CLASP missions. In this paper, we investigate the impact of the angular and frequency coupling in coherent scattering processes in the radiative transfer modeling of the Mg ii doublet polarization profiles. In particular, we aim to assess how the widely used angle-average approximation affects the predicted polarization. By solving the radiative transfer problem in 1D semiempirical atmospheric models, we find that this approximation is suitable in the absence of magnetic fields, but there can be measurable differences in magnetized models, mainly in the linear polarization profiles close to the core of the Mg ii k line. We then test the suitability of the approximation in more realistic scenarios, solving the radiative transfer problem pixel-by-pixel in a 3D atmospheric model resulting from a magnetohydrodynamic simulation and mimicking the degradation of the CLASP2 instrument, as well as in several 1D atmospheric models resulting from the Stokes inversion of the CLASP2 data. We find that the impact of the angle-average approximation is greatly diminished at the resolution of the CLASP2 observations. We also find that to suitably include angle-dependent effects in 1D radiative transfer modeling, it is sufficient to initialize the problem with the angle-average solution and then perform a few (angle-dependent) iterations, dramatically reducing the computational cost.

Increasing digital maturity in innovative development management in a company

Digital maturity level determines the ability of an enterprise to quickly and effectively implement digital management tools, including in innovative activities. Increasing digital maturity is becoming a necessary task for innovative and active enterprises aimed at increasing business sustainability. Studying theoretical and methodological aspects of enterprises’ digital maturity allowed us to identify a range of current issues. Theoretical substantiation of the concept and content of an enterprise’s digital maturity has been carried out, and its key characteristics have been formed. Digital maturity assessment stages and tasks of increasing digital maturity in managing an enterprise’s innovative development have been highlighted. Methodological approaches digital maturity assessment has made it possible to form an authors’ way of organizing and managing digital maturity level. The authors recommend to create a working group and a Coordinating council for managing an enterprise’s digital maturity. The functional content of the activities of the council and its specialists at different levels has been proposed. To solve the problem of determining the time spent on managing and monitoring digital maturity, a mathematical model for time redistribution for operations has been developed. The optimization of operations complexity redistribution in monitoring an enterprise’s digital maturity has been carried out. The article concludes that effective organizational and technological management of an enterprise will open up the possibility of increasing its digital maturity level.

Cascading failure dynamics on higher-order networks with load redistribution.

The phenomenon of load redistribution in complex networks has garnered extensive attention due to its profound impact and widespread occurrence. In recent years, higher-order structures have offered new insights into understanding the structures and dynamic processes of complex networks. However, the influence of these higher-order structures on the dynamics of load redistribution, cascade failures, and recovery processes remains to be fully explored. In this study, we propose the load redistribution model with higher-order structures and recovery strategies of cascade failure based on functional upgrading and reconstruction mechanisms. In the cascading failure process with load redistribution and higher-order recovery strategies, we find that higher-order structures can induce a discontinuous phase transition at the low proportion of load redistribution, and the dynamic process displays a dual character of being robust yet fragile. These findings have been examined in both real and classical modeled networks. Interestingly, the largest connected component exhibits three distinct modes as the attack ratio increases at high densities of higher-order structures and recovery mechanisms.

Full non-LTE spectral line formation

In the present paper we consider the full nonlocal thermodynamic equilibrium (non-LTE) radiation transfer problem. This formalism allows us to account for deviation from equilibrium distribution of both the radiation field and the massive particles. In the present study, two-level atoms with broadened upper level represent the massive particles. In the absence of velocity-changing collisions, we demonstrate the analytic equivalence of the full non-LTE source function with the corresponding standard non-LTE partial frequency redistribution (PFR) model. We present an iterative method based on operator splitting techniques that can be used to numerically solve the problem at hand. We benchmark it against the standard non-LTE transfer problem for a two-level atom with PFR. We illustrate the deviation of the velocity distribution function of excited atoms from the equilibrium distribution. We also discuss the dependence of the emission profile and the velocity distribution function on elastic collisions and velocity-changing collisions.

Exact Solutions for Radiative Transfer with Partial Frequency Redistribution

The construction of exact solutions for radiative transfer in a plane-parallel medium has been addressed by Hemsch and Ferziger in 1972 for a partial frequency redistribution model of the formation of spectral lines consisting in a linear combination of frequency coherent and fully incoherent scattering. The method of solution is based on an eigenfunction expansion of the radiation field, leading to two singular integral equations with Cauchy or Cauchy-type kernels, that have to be solved one after the other. We reconsider this problem, using as starting point the integral formulation of the radiative transfer equation, where the terms involving the coupling between the two scattering mechanisms are clearly displayed, as well as the primary source of photons. With an inverse Laplace transform, we recover the singular integral equations previously established and, with Hilbert transforms as in the previous work, recast them as boundary value problems in the complex plane. Their solutions are presented in detail for an infinite and a semi-infinite medium. The coupling terms are carefully analyzed and consistency with either the coherent or the incoherent limit is systematically checked. We recover the important result of the previous work that an exact solution exists for an infinite medium, whereas for a semi-infinite medium, which requires the introduction of half-space auxiliary functions, the solution is given by a Fredholm integral equation to be solved numerically. The solutions of the singular integral equations are used to construct explicit expressions providing the radiation field for an arbitrary primary source and for the Green’s function. An explicit expression is given for the radiation field emerging from a semi-infinite medium.

Modeling oxygen transport in Cr doped UO2 fuel with the TAF-ID during power transients

This paper proposes an efficient coupling between an oxygen redistribution model and the Thermodynamics for Advanced Fuels-International Database (TAF-ID) to describe the behavior of fission products, actinides, and dopant in a uranium dioxide matrix. The formulation of oxygen migration in the fuel is a function of the oxygen (and uranium) chemical potential gradient. The proposed formulation does not require the introduction of the Soret term and relies solely on the known mobilities of uranium and oxygen in the fuel. This coupling is applied to the simulation of a power ramp on a chromia-doped fuel rod using the PLEIADES/ALCYONE fuel performance code. The simulations successfully reproduce most of the available experimental observations on the fission products (Cs, Mo, Ru) and on the chromium dopant.

Phenomenological model of moisture redistribution in porcelain stoneware spray-dried powder stored in silo

Porcelain stoneware powder requires at least 24 h of silo storage to stabilize temperature and moisture content after spray-drying. Homogeneity is crucial to produce dimensionally stable tiles. The objective was to model moisture redistribution in granules of different sizes using phenomenological formulation. An original multiscale approach incorporated segregation into the coupled mass/heat transfer equations. Finite element method numerically solved and accurately estimated moisture content in fines, intermediate, and coarse granules in accordance with industrial data. The starting moisture content difference of 3.19% between coarse and fine granules was reduced to 1.62% and 0.88% for 24 h and 48 h storage times, respectively. Output temperature estimates agreed with measurements (maximum error of 17%). Higher thermal gradients evidenced the cooling effect as moisture content increased in all granules at the wall, observed as condensed water in the actual system. This model could be applied to any material in storage within a center-filled silo.

Inter‐Regional Food‐Water‐Income Synergy Through Bi‐Level Crop Redistribution Model Coupled With Virtual Water: A Case Study of China’s Hetao Irrigation District

AbstractIncorporating water footprints and virtual water into crop redistribution provides a new approach for efficient water resources utilization and synergistic development of water surplus and scarce regions. In this work, the absolute and comparative advantage of the production‐based blue and gray water footprint (PWFblue and PWFgray), the calorie‐based blue water footprint (CWFblue) and the net benefit‐based blue water footprint (NBWFblue) were used as coefficients to establish a bi‐level crop redistribution model. The mode considers upper‐level decision makers interested in maximizing food security and ecological security and lower‐level decision makers interested in water use efficiency, water use benefits and net benefits. The model was applied in the Hetao Irrigation District (HID), China. The results showed that after optimization, the PWFblue, CWFblue, NBWFblue, and gray water footprint (GWF) of the HID were reduced by 23.32%, 5.60%, 17.40%, and 6.67%, respectively. National benefits were improved, especially when considering synergistic optimization, although the net benefits of HID was affected. The calorie supply increased by 9.6 × 109 kcal, the GWF decreased by 8.29 × 106 m3, and water use efficiency and benefits were improved in China. In contrast, the calorie supply and the net benefits of the HID decreased, while the GWF increased. Moreover, multiple stakeholders were involved in crop redistribution and required national synergies. The bi‐level model proved more suitable than the multi‐objective model. The model proposed in this work considers synergies outside the region in crop redistribution within the region, and can provide new insight for water and soil resources management in arid and semi‐arid regions.

A stochastic programming model for free-floating shared bike redistribution considering bike gathering

We study a stochastic free-floating shared bike redistribution problem, which first gathers bikes randomly scattered around the hotspots of a city and then transships the gathered bikes among the hotspots to achieve a better supply–demand balance. In the literature, the bike gathering operation and the associated stochasticity, although significant for shared bike redistribution practice, are rarely considered. To fill the gap, we propose a two-stage stochastic programming model that explicitly incorporates the bike-gathering cost with two formulations. In the planning stage, the deployment of gathering sites and the allocation of gathering staff are determined. In the operation stage, the gathering, transshipment and replenishment of shared bikes are optimized based on the decisions of the planning stage and the realization of the uncertain supply and demand of free-floating shared bikes in space. With a case study based on real data from the Mobike company in Beijing, China, we illustrate the real-world applications of our proposed model, highlight the importance of considering the cost of bike gathering when planning free-floating shared bike redistribution, and gain managerial insights for better field practices.

Improvements to the Blade Element Momentum Formulation of OpenFAST for Skewed Inflows

In this work, we modify the blade element momentum algorithm of OpenFAST to improve its predictions under large skewed inflow conditions. We use the well-known Glauert’s skew correction and introduce continuous extension of the model for high-thrust conditions. We present the rationale behind Glauert’s empirical model and discuss the different conventions possible for the axial induction factor. We verify the model against the higher-fidelity lifting-line vortex method and blade-resolved computational fluid dynamics, and we observe that the new implementation enhances the accuracy and reliability of OpenFAST’s aerodynamic modeling capabilities in conditions involving large skew angles. For the parametric studies run using the different codes, we find that the power changes with the skew angle as cos1.7(θ skew) and the thrust as cos0.65(θ skew). An analysis of the azimuthal variation of the induced velocities in the rotor plane reveals that current redistribution models used in blade element momentum codes may need to be refined.

Nitrile Vibrational Lifetimes as Probes of Local Electric Fields.

Optical measurements of electric fields have wide-ranging applications in the fields of chemistry and biology. Previously, such measurements focused on shifts in intensity or frequency. Here, we show that nitrile vibrational lifetimes can report local electric fields through ultrasensitive picosecond mid-infrared-near-infrared double-resonance fluorescence spectro-microscopy on Rhodamine 800. Using a robust convolution fitting approach, we observe that the nitrile vibrational lifetimes are strongly linearly correlated (R2 = 0.841) with solvent reaction fields. Supported by density functional theory, we rationalize this trend through a doorway model of intramolecular vibrational energy redistribution. This work provides new fundamental insights into the nature of vibrational energy flow in large polyatomic molecular systems and establishes a theoretical basis for electric field sensing with vibrational lifetimes, offering a new experimental dimension for probing intracellular electrostatics.

A millennium of arable land use – the long-term impact of tillage and water erosion on landscape-scale carbon dynamics

Abstract. In the last decades, soils and their agricultural management have received great scientific and political attention due to their potential to act as a sink of atmospheric carbon dioxide (CO2). Agricultural management has strong potential to accelerate soil redistribution, and, therefore, it is questioned if soil redistribution processes affect this potential CO2 sink function. Most studies analysing the effect of soil redistribution upon soil organic carbon (SOC) dynamics focus on water erosion and analyse only relatively small catchments and relatively short time spans of several years to decades. The aim of this study is to widen this perspective by including tillage erosion as another important driver of soil redistribution and by performing a model-based analysis in a 200 km2 sized arable region of northeastern Germany for the period since the conversion from forest to arable land (approx. 1000 years ago). The spatially explicit soil redistribution and carbon (C) turnover model SPEROS-C was applied to simulate lateral soil and SOC redistribution and SOC turnover. The model parameterisation uncertainty was estimated by simulating different realisations of the development of agricultural management over the past millennium. The results indicate that, in young moraine areas, which are relatively dry but have been intensively used for agriculture for centuries, SOC patterns and dynamics are substantially affected by tillage-induced soil redistribution processes. To understand the landscape-scale effect of these redistribution processes on SOC dynamics, it is essential to account for long-term changes following land conversion as typical soil-erosion-induced processes, e.g. dynamic replacement, only take place after former forest soils reach a new equilibrium following conversion. Overall, it was estimated that, after 1000 years of arable land use, SOC redistribution by tillage and water results in a current-day landscape-scale C sink of up to 0.66 ‰ yr−1 of the current SOC stocks.

Experimental and theoretical model of microvascular network remodeling and blood flow redistribution following minimally invasive microvessel laser ablation.

Overly dense microvascular networks are treated by selective reduction of vascular elements. Inappropriate manipulation of microvessels could result in loss of host tissue function or a worsening of the clinical problem. Here, experimental, and computational models were developed to induce blood flow changes via selective artery and vein laser ablation and study the compensatory collateral flow redistribution and vessel diameter remodeling. The microvasculature was imaged non-invasively by bright-field and multi-photon laser microscopy, and optical coherencetomography pre-ablation and up to 30 days post-ablation. A theoretical model of network remodeling was developed to compute blood flow and intravascular pressure and identify vessels most susceptible to changes in flow direction. The skin microvascular remodeling patterns were consistent among the five specimens studied. Significant remodeling occurred at various time points, beginning as early as days 1-3 and continuing beyond day 20. The remodeling patterns included collateral development, venous and arterial reopening, and both outward and inward remodeling, with variations in the time frames for each mouse. In a representative specimen, immediately post-ablation, the average artery and vein diameters increased by 14% and 23%, respectively. At day 20 post-ablation, the maximum increases in arterial and venous diameters were 2.5× and 3.3×, respectively. By day 30, the average artery diameter remained 11% increased whereas the vein diameters returned to near pre-ablation values. Some arteries regenerated across the ablation sites via endothelial cell migration, while veins either reconnected or rerouted flow around the ablation site, likely depending on local pressure driving forces. In the intact network, the theoretical model predicts that the vessels that act as collaterals after flow disruption are those most sensitive to distant changes in pressure. The model results correlate with the post-ablation microvascular remodeling patterns.

A model of redistribution of dopant in a multilayer structure with changing overgrowth regime

In this paper, we analyzed the redistribution of dopants in a multilayer structure during the overgrowing of a doped area. The effect of changing of regimes of overgrowing of the doped area on the redistribution of dopant was analyzed. An analytical approach for analysis of the redistribution of dopant was introduced. The approach makes it possible to take into account the changing parameters of the considered process in space and time together, as well as the nonlinearity of the mass transport.

РАЗВИТИЕ ПРОГРАММНОГО УПРАВЛЕНИЯ РЕГИОНАЛЬНЫМИ АГРОПРОДОВОЛЬСТВЕННЫМИ СИСТЕМАМИ

Regional agro-food systems are important components of the national economic complex, ensuring the country's food security, development of rural areas, and improving the level and quality of life of the population. In modern conditions, government programs are becoming the main tool for strategic planning of industries, regions and the national economic system as a whole. The new system for managing state programs, approved in 2021, is aimed at eliminating many problems in the implementation of the program-target method, in particular, eliminating the ineffective use of budget resources and strengthening interdepartmental interactions. A new approach to the development, monitoring and implementation of state programs in the agro-food sector involves the addition of state programs with a number of parameters aimed at the fullest implementation of Russia’s national development goals. Proposals for improving the state programs of the Saratov region “Development of agriculture and regulation of markets for agricultural products, raw materials and food in the Saratov region” and “Integrated development of rural areas” are substantiated. The importance of transforming the redistribution model of financing the regional economy, which creates certain problems for regions when co-financing state programs, is emphasized.

Multi-scale and multi-physics simulation of central segregation in an equiaxed dendritic mushy zone during continuous casting of steel

Centreline segregation during continuous casting of steel is highly detrimental to the end-product mechanical properties. In this study, a 3D multi-scale and multi-physics model is developed and validated that directly predicts alloy segregation occurring in peritectic steel grades having centreline equiaxed grain morphology. The model consists of four models: (1) a 1D macroscale heat transfer and solidification model, (2) a 3D mesoscale dendritic solidification model, (3) a 3D mesoscale dendritic fluid flow model, and (4) a 3D mesoscale solute transport and redistribution model. The use of a mesoscale domain where the solid and liquid phases are separately discretized allows for consideration of physical phenomena affecting segregation that are classically hidden by the averaging procedures of fully continuum approaches. Thus the new model is able to account for the multiple phenomena occurring during continuous casting while also directly considering the stochastic effects resulting from grains having randomly-placed nuclei as well as interactions between the liquid and solid phases. The results demonstrate that solute partitioning combined with intra-dendritic fluid flow leads eventually to liquid channels enriched with solute that result in centreline segregation. The predicted composition in these discrete liquid channels shows excellent agreement with a Mn centreline segregation profile experimentally-measured via microscopic X-ray fluorescence of a commercially-cast steel slab. Finally, the effects of alloy composition, and soft reduction on the degree of centreline segregation are examined.

WE economy: Potential of mutual aid distribution based on moral responsibility and risk vulnerability.

Reducing wealth inequality is a global challenge that requires the transformation of the economic systems that produce inequality. The economic system comprises: (1) gifts and reciprocity, (2) power and redistribution, (3) market exchange, and (4) mutual aid without reciprocal obligations. Current inequality stems from a capitalist economy consisting of (2) and (3). To sublimate (1), the human economy, to (4), the concept of a "mixbiotic society" has been proposed in the philosophical realm. In this society, free and diverse individuals mix, recognize their respective "fundamental incapability," and sublimate them into "WE" solidarity. Moreover, the economy must have a moral responsibility as a co-adventurer and consider its vulnerability to risk. This study focuses on two factors of mind perception-moral responsibility and risk vulnerability-and proposes a novel wealth distribution model between the two agents following an econophysical approach, whereas the conventional model dealt with redistribution through taxes and institutions. Three models are developed: a joint-venture model in which profit/losses are distributed based on their factors, a redistribution model in which wealth stocks are redistributed periodically based on their factors in the joint-venture model, and a "WE economy" model in which profit/losses are distributed based on the ratio of each other's factors. A simulation comparison reveals that WE economies are effective in reducing inequality, resilient in normalizing wealth distribution as advantages, and susceptible to free riders as disadvantages. However, this disadvantage can be compensated for by fostering fellowship and using joint ventures. This study presents the effectiveness of moral responsibility and risk vulnerability, complementarity between the WE economy and joint economy, and the direction of the economy in reducing inequality. Future challenges include developing an advanced model based on real economic analysis and economic psychology and promoting its fieldwork for worker coops and platform cooperatives to realize a desirable mixbiotic society.