Simple Description Research Articles

Ingredients for Generalized Models of κ-Phase Organic Charge-Transfer Salts: A Review

The families of organic charge-transfer salts κ-(BEDT-TTF)2X and κ-(BETS)2X, where BEDT-TTF and BETS stand for the organic donor molecules C10H8S8 and C10H8S4Se4, respectively, and X for an inorganic electron acceptor, have been proven to serve as a powerful playground for the investigation of the physics of frustrated Mott insulators. These materials have been ascribed a model character, since the dimerization of the organic molecules allows to map these materials onto a single band Hubbard model, in which the dimers reside on an anisotropic triangular lattice. By changing the inorganic unit X or applying physical pressure, the correlation strength and anisotropy of the triangular lattice can be varied. This has led to the discovery of a variety of exotic phenomena, including quantum-spin liquid states, a plethora of long-range magnetic orders in proximity to a Mott metal-insulator transition, and unconventional superconductivity. While many of these phenomena can be described within this effective one-band Hubbard model on a triangular lattice, it has become evident in recent years that this simplified description is insufficient to capture all observed magnetic and electronic properties. The ingredients for generalized models that are relevant include, but are not limited to, spin-orbit coupling, intra-dimer charge and spin degrees of freedom, electron-lattice coupling, as well as disorder effects. Here, we review selected theoretical and experimental discoveries that clearly demonstrate the relevance thereof. At the same time, we outline that these aspects are not only relevant to this class of organic charge-transfer salts, but are also receiving increasing attention in other classes of inorganic strongly correlated electron systems. This reinforces the model character that the κ-phase organic charge-transfer salts have for understanding and discovering novel phenomena in strongly correlated electron systems from a theoretical and experimental point of view.

Dietitians Working in Continuing Care Facilities in Nova Scotia: Pre- and Post-COVID-19 First Wave.

Continuing care (CC) facilities have been impacted by a growing demand for services, insufficient resources for the provision of quality food and nutrition care, and, most recently, the COVID-19 pandemic. This study explored the roles and responsibilities of dietitians working in CC facilities in Nova Scotia (NS) before and after the COVID-19 first wave. Using ethics-approved questionnaires, the estimated 75 dietitians working in CC facilities in NS were surveyed in Fall 2019 and Fall 2020 about their roles and responsibilities. Twenty responded to the first questionnaire and 15 to the second. Analysis of data included simple statistical and qualitative description methods. The findings highlighted the complexities and challenges faced by these dietitians in the provision of resident nutrition care, overseeing foodservices, training staff and dietetic interns, and contributing to facility specific care committees before and after the COVID-19 first wave. There is a need to advocate for minimum standards for dietetic and foodservice funding in CC facilities based on higher acuity and complex care needs of residents and considering the multifaceted roles of dietitians in CC. Efforts to improve awareness about the roles of dietitians working in CC among resident families, other dietitians, and dietetic interns are also needed.

Simple analytical description of contact pressure and wear evolution in non-conformal contacts

The present study proposes an analytical approach to describe contact pressure and wear evolution in line and point contacts. Starting from the unworn condition, described by Hertz theory, modifications of geometry and pressure distribution due to wear are included. Under the basic assumption of parabolic wear and pressure profiles, derived from Finite Element simulations, simple equations governing the phenomenon are derived, where the maximum wear depth evolution is described by a first order differential equation which can be easily solved. Interestingly, the maximum pressure remains dependent on the radius of curvature at the nominal contact point according to Hertz theory, but pressure is not null at the extremes of the contact region. The contact width can be derived from equilibrium conditions and wear law. The reliability of the procedure is proved by the perfect agreement with Finite Element simulations.

Majority dynamics and the median process: Connections, convergence and some new conjectures

We consider the median dynamics process in general graphs. In this model, each vertex has an independent initial opinion uniformly distributed in the interval [0,1] and, with rate one, updates its opinion to coincide with the median of its neighbors. This process provides a continuous analog of binary majority dynamics. We deduce properties of median dynamics through this connection and raise new conjectures regarding the behavior of majority dynamics on general graphs. We also prove these conjectures on some graphs where majority dynamics has a simple description.

Large-Scale Algorithmic Search Identifies Stiff and Sloppy Dimensions in Synaptic Architectures Consistent With Murine Neocortical Wiring.

Complex systems can be defined by "sloppy" dimensions, meaning that their behavior is unmodified by large changes to specific parameter combinations, and "stiff" dimensions, whose change results in considerable behavioral modification. In the neocortex, sloppiness in synaptic architectures would be crucial to allow for the maintenance of asynchronous irregular spiking dynamics with low firing rates despite a diversity of inputs, states, and short- and long-term plasticity. Using simulations on neural networks with first-order spiking statistics matched to firing in murine visual cortex while varying connectivity parameters, we determined the stiff and sloppy parameters of synaptic architectures across three classes of input (brief, continuous, and cyclical). Algorithmically generated connectivity parameter values drawn from a large portion of the parameter space reveal that specific combinations of excitatory and inhibitory connectivity are stiff and that all other architectural details are sloppy. Stiff dimensions are consistent across input classes with self-sustaining synaptic architectures following brief input occupying a smaller subspace as compared to the other input classes. Experimentally estimated connectivity probabilities from mouse visual cortex are consistent with the connectivity correlations found and fall in the same region of the parameter space as architectures identified algorithmically. This suggests that simple statistical descriptions of spiking dynamics are a sufficient and parsimonious description of neocortical activity when examining structure-function relationships at the mesoscopic scale. Additionally, coarse graining cell types does not prevent the generation of accurate, informative, and interpretable models underlying simple spiking activity. This unbiased investigation provides further evidence of the importance of the interrelationship of excitatory and inhibitory connectivity to establish and maintain stable spiking dynamical regimes in the neocortex.

Effect of local inhomogeneous permeability of Ni-Mn-Ga in dependency of constrains

Magnetic shape memory alloys are a promising but rather novel smart material class. A test stand was developed and verified to characterize commercially available samples. The test stand generates a homogeneous magnetic field within the air gap when no sample is inserted. Once a Ni-Mn-Ga sample is inserted, the field remains homogeneous in the horizontal but not in the vertical direction. Rotating the sample around the long edge leads to a mirrored behavior. An FEM simulation based on the simplified description of the switching effect was built up. The simulation reproduced the experimental data principle but not in detail. The simplified description of the effect helps to understand the behavior of magnetic memory alloys, but for a deeper understanding micro-simulations with precise boundary conditions are necessary.

Examining the link between integrated management systems and firm performance: do the integration strategies matter?

PurposeThis study attempts to examine the performance differences between firms with and without integrated management systems (IMSs), and the impact of three integration strategies (i.e. implementing quality management system (QMS) first, then environmental management system (EMS) (QMS + EMS); implementing EMS first, then QMS (EMS + QMS); implementing QMS and EMS simultaneously (QMS − EMS)) on firm performance to reveal the IMS–performance relationship and provide empirical evidence.Design/methodology/approachTwo panel datasets were collected during 2009–2019. This study used the Mann–Whitney non-parametric test and a sample of 33,155 observations from 4,316 Chinese listed firms to compare the performance differences between the IMS and non-IMS groups through performance indicators. This study also examined the effects of three integration strategies on firm performance using a cross-sectional time-series feasible generalized least squares (FGLS) regression model and a sample of 11,289 observations from 2,037 firms.FindingsThe results show that significant performance differences exist between IMS and non-IMS firms; however, the performance of firms with an IMS is not always better than that of firms without IMS. Furthermore, the simultaneous integration strategy has a positive impact, whereas sequential integration strategies (QMS + EMS and EMS + QMS) negatively affect firm performance. Compared with the EMS + QMS strategies, the QMS + EMS strategies have a more prominent effect on firm performance. Simultaneous strategies are more effective than sequential strategies.Practical implicationsFirms should fully consider the potential benefits and costs associated with the difficulties of IMS implementation and the implementation order of different management systems and the potential effects of the management systems in different conditions. Firms also should try to develop internal capabilities through implementing different integration strategies.Originality/valueBy comparing performance differences between firms with and without IMS, this study enriches the understanding of the performance benefits of IMS implementation in the Chinese context. By examining the impact of integration strategies that follow different sequences on firm performance, this study promotes an in-depth understanding of the integration strategies and their performance implications beyond simple descriptions and also provides new insights into operations strategy models.

Topological models to infer multiphase interstellar medium properties

Context.Spectroscopic observations of high-redshift galaxies slowly reveal the same complexity of the interstellar medium (ISM) as expected from resolved observations in nearby galaxies. While providing, in principle, a wealth of diagnostics concerning galaxy evolution, star formation, or the nature and influence of compact objects, such high-zspectra are often spatially and spectrally unresolved, and inferring reliable diagnostics represents a major obstacle. Bright, nearby, unresolved galaxies observed in the optical and infrared domains provide many constraints to design methods to infer ISM properties, but they have so far been limited to deterministic methods and/or with simple topological assumptions (e.g., single 1D model).Aims.It is urgent to build upon previous ISM multiphase and multicomponent methods by using a probabilistic approach that makes it possible to derive probability density functions for relevant parameters while also enabling a large number of free parameters with potential priors. The goal is to provide a flexible statistical framework that is agnostic to the model grid and that considers either a few discrete components defined by their parameter values and/or statistical distributions of parameters. In this paper, we present a first application with the objective to infer probability distributions of several physical parameters (e.g., the mass of H0, H2, escape fraction of ionizing photons, and metallicity) for the star-forming regions of the metal-poor dwarf galaxy I Zw 18 in order to confirm the low molecular gas content and high escape fraction of ionizing photons from Hiiregions.Methods.We present a Bayesian approach to model a suite of spectral lines using a sequential Monte Carlo method provided by the Python package PyMC which combines several concepts such as tempered likelihoods, importance sampling, and independent Metropolis-Hastings chains. The algorithm, provided by the associated code MULTIGRIS, accepts a few components which can be represented as sectors around one or several stellar clusters, or continuous (e.g., power-law, normal) distributions for any given parameter. We applied this approach to a grid of models calculated with the photoionization and photodissociation code Cloudy in order to produce topological models of I Zw 18.Results.The statistical framework we present makes it possible to consider a large number of spectroscopic tracers, with the extinction and systematic uncertainties as potential additional random variables. We applied this technique to the galaxy I Zw 18 in order to reproduce and go beyond previous topological models specifically tailored to this object. While our grid is designed for global properties of low-metallicity star-forming galaxies, we were able to calculate accurate values for the metallicity, number of ionizing photons, masses of ionized and neutral hydrogen, as well as the dust mass and the dust-to-gas mass ratio in I Zw 18. We find a relatively modest amount of H2(~105M⊙) which is predominantly CO-dark and traced by C+rather than C0. Nevertheless, more than 90% of the [Cii] emission is associated with the neutral atomic gas. Our models confirm the necessity to include an X-ray source with an inferred luminosity in good agreement with direct X-ray observations. Finally, we investigate the escape fraction of ionizing photons for different energy ranges. While the escape fraction for the main Hiiregion lies around 50–65%, we show that most of the soft X-ray photons are able to escape and may play a role in the ionization and heating of the circumgalactic or intergalactic medium.Conclusions.Multicomponent ISM models associate a complex enough distribution of matter and phases with a simple enough topological description to be constrained with probabilistic frameworks. Despite ignoring effects such as reflected light, the diffuse radiation field, or ionization by several non-cospatial sources, they remain well adapted to individual Hiiregions and to star-forming galaxies dominated by one or a few Hiiregions, and the improvement due to the combination of several components largely compensates for other secondary effects.

중국어 역사문법의 최신 연구동향 분석 —2012년부터 2022년까지의 古汉语研究와 中国语文을 중심으로

This article reviews recent research trends in Historical Grammar of Chinese based on 212 articles published in Research In Ancient Chinese Language(古汉语研究) and Studies of The Chinese Language(中国语文) from 2012 to 2022. In this field, ‘words’ are being studied more than ‘constructions’, and ‘adverbs’ are being studied the most. There are the most studies on the period of ‘Archaic Chinese’ among three periods of Ancient Chinese, that is Archaic, Middle Ancient and Modern Ancient Chinese. Diachronic research is more focused rather than synchronic research. Research methods of Historical Grammar of Chinese can be largely classified into two types: simple descriptions and theoretical interpretations, and we find more studies of the former than the latter. Theoretical interpretations studies can be subdivided into five types: (1) studies on mechanisms and motivations of grammaticalization, (2) linguistic typology based studies, (3) construction grammar theory based studies, (4) cognitive grammar theory based studies, (5) generative grammar theory based studies. Among these five types, (1) accounts for the highest proportion and (4), (5) accounts for a relatively low proportion. The article concludes by suggesting that theoretical interpretations studies should be conducted more actively, and the subjects should be more associated with Modern Chinese. There also should be a unified understanding of mechanisms and motivations of grammaticalization and the key elements should be found among these.

Use of augmented reality in chromatography learning: How is this dynamic visual artifact fostering the visualization capacities of chemistry undergraduate students?

Developing chemistry students' capability to use representations to explain phenomena is a challenging task for educators. To overcome chemistry students' learning difficulties, strategies that favor the development of visualization capabilities have been identified as productive. We are particularly interested in exploring the use of augmented reality in chemistry education to foster the development of those capabilities in undergraduate students. Our research objective was to analyze the contribution of augmented reality to support undergraduate chemistry students' visualization capacities while explaining the physical-kinetic processes of chromatography. Using an exploratory case study approach, we designed and conducted four task teaching and learning sequences, with seven Augmented Reality markers embedded. Thirty-eight undergraduate students, who voluntarily agreed to participate, explained the different elution rates of pigments in a chromatographic column. Their written accounts were analyzed to identify the level of sophistication of their representations. After using Augmented Reality, students' representations progressed from simple macroscopic descriptions of observed phenomena to explanations of processes where scientific ideas and microscopic representations were used as supporting evidence. Our study shows that the use of Augmented Reality has the potential to favor a more sophisticated use of representations when undergraduate students explain chromatographic processes. However, there are still limitations in reaching the highest levels of performance described in the literature.

Ignition and combustion characteristics of coal - water fuels based on coal & semi-coke

AnnotationThe article presents the results of experimental and theoretical studies of the ignition processes of coal- water fuel (CWF) drops made from coals of various degrees of metamorphism and coal semi-coke of these coals. It is shown that the preliminary torrefaction of coal leads to a significant improvement in environmental performance (50–60% reduction in flue gas concentrations of the main anthropogenic coal combustion products: nitrogen oxides NOx and sulfur SOx) of coal- water fuel combustion processes. This effect is most pronounced during the combustion of CWF based on lignite. Also, according to the results of the experiments, the ignition delay times of typical droplets (in the initial state), and then particles (after drying the near-surface fuel layer) of coal- water fuel s based on coals and coal semi-coke were established. It has been established that the ignition delay times of coal- water fuel particles based on pre-torrefied coals at relatively low ambient temperatures (Tg≤873 K) are on average 20% higher than when igniting CWF droplets based on natural coal. Under conditions of high-temperature heating, the ignition delay times of CWF particles made from natural coal and semi-coke differ insignificantly (no more than 2%).Based on the results of the experimental studies, a mathematical model of the ignition process of a coal- water fuel drop based on semi-coke was developed, which differs from the known ones in a relatively simple description of the most significant processes of thermal preparation and ignition, but at the same time retains a fairly high predictive potential. Using the previously developed method of quasi-stationary "thermal approximation" with the selection of an asymptotic estimate, an analytical solution is derived for the essentially nonlinear problem of coal- water fuel droplet ignition. ColloquiumAn analysis of modern political discourse shows that the information entropy associated with the problem of the anthropogenic impact of mankind on the planet's atmosphere as a result of the operation of energy facilities is constantly growing. At the same time, the constant growth of energy consumption in the world makes it necessary to introduce more and more new heat and power generating capacities. For a long time (the last 30 years) it was believed that the solution to all energy problems is the large-scale introduction of non-traditional renewable energy sources (solar batteries and wind power generators - RES) into the overall balance of energy generation. However, recent events in North America and Western Europe show that the potential for using renewable energy sources is significantly limited, and electricity generation from these renewable energy sources is still significantly unstable. In this regard, a new impetus for development is acquiring coal energy. However, the main problem of coal power engineering, the anthropogenic impact of thermal power plants on the planet's atmosphere, remains unresolved. This situation creates prerequisites for the development of new "clean" coal technologies with complete sequestration of anthropogenic emissions generated during coal combustion. This article presents the results of experimental and theoretical studies of the combustion processes of coal-water suspensions prepared from pre-torrefied coals. As a result of preliminary thermal (pyrolysis under conditions of high-temperature heating in an inert environment) preparation of coal, gaseous pyrolysis products are formed and removed into the external environment, a large proportion of which are hydrogen sulfide (the main source of sulfur oxides) and hydrocyanic acid (the main source of nitrogen oxides). After the preliminary pyrolysis of coal, a mixture of coke carbon and the mineral part of coal remains. When burning a coal-water suspension based on torrefied coal, only carbon dioxide and water vapor are formed. The latter can be relatively easily condensed and returned back to the power generation cycle (or disposed of). Accordingly, the combustion of CWF based on torrefied coal creates the prerequisites for the fundamental justification of the technology for environmentally friendly combustion of coal in the combustion chambers of gas turbine plants operating on the Allam cycle.

The Mathcad system usage in finding normal equations in the description of food extraction processes

The article describes using electronic computer systems, particularly Mathcad when finding standard equations for building mathematical models of technological processes in the chemical and food industries. Classical mathematical models of the extraction process are usually based on analyzing the differential equation of diffusion under appropriate boundary and initial conditions. Also, when describing mathematical models, Fick's equation, the equation of the adsorption pore model of molecular-statistical studies, models that take into account the physics of the process of substance transfer in a capillary-porous medium, etc., are used. Modeling of mass transfer processes under the influence of the intensifying action of the microwave field is described in the studies for the systems “coffee – water” and “oak wood – water-alcohol solution”, “coffee grounds – alcohol,” “amorant – hexane,” a mechanism of the combined process of mass transfer of extractive substances from a porous structure is proposed into solution The description of mass transfer processes under the influence of microwave field intensification is rather complicated. The mass transfer of extractive substances from porous structures to the solution occurs through the distribution of concentrations at the “solid–solvent” interface. However, it passes from the inner part through the outer part, through the capillaries into the border diffusion layer. Complex mathematical models for mass transfer processes do not have analytical solutions. When using the Mathcad system to solve nonlinear systems of equations, it is recommended to use the built-in find function in the calculated Given block. Also, the universal function genfit is quite adequate, which makes it possible to determine unknown parameters for nonlinear combinations of functions by the method of least squares. This system was used in describing extraction processes in the structure of interaction “oil – containing raw materials – solvent” with the intensifying effect of the microwave field. Such simplified analytical description systems are recommended to be used along with experimental modeling with the classic use of similarity theory and the “dimensional analysis” method. The final result of these directions is the construction of sound engineering methods for the design of extractors for industrial purposes.

A simple thermodynamic description of phase separation of Nup98 FG domains

The permeability barrier of nuclear pore complexes (NPCs) controls nucleocytoplasmic transport. It retains inert macromolecules but allows facilitated passage of nuclear transport receptors that shuttle cargoes into or out of nuclei. The barrier can be described as a condensed phase assembled from cohesive FG repeat domains, including foremost the charge-depleted FG domain of Nup98. We found that Nup98 FG domains show an LCST-type phase separation, and we provide comprehensive and orthogonal experimental datasets for a quantitative description of this behaviour. A derived thermodynamic model correlates saturation concentration with repeat number, temperature, and ionic strength. It allows estimating the enthalpy, entropy, and ΔG (0.2 kJ/mol, 0.1 kB·T) contributions per repeat to phase separation and inter-repeat cohesion. While changing the cohesion strength strongly impacts the strictness of barrier, these numbers provide boundary conditions for in-depth modelling not only of barrier assembly but also of NPC passage.

Moisture as a Driver of Long-Term Threats to Timber Heritage—Part II: Risks Imposed on Structures at Local Sites

Timber heritage sites are vulnerable to damage from moisture. Simple meteorological descriptions of climate need to be tuned to capture drivers that threaten heritage, including dimensional change, insect attack and mould growth. Global climate models often provide projections through to the end of the 21st century but need to be translated to a local level to reveal processes of deterioration at specific sites. Translation to a local level can be challenging and requires the use of local information from a range of sources. This translation is explored over a range of sites facing different climate pressures, including fungal and insect risk at Harmondsworth Great Barn, England; changes in humidity range, salt risk and algal growth in rural timber buildings in the Midwestern states, USA; wind-driven rain impacts on board houses in Freetown, Sierra Leone; and rainfall and humidity range on timber buildings among the tropical rainforests of the Amazon, Congo Basin and Southeast Asia. Evidence-based narratives provide a tool to incorporate a multiplicity of local information to enrich projections and the interpretation of the model output. These could build trust and aid decision-making based on future projections, which are inherently uncertain.

A method for semantic-based image retrieval using hierarchical clustering tree and graph

Semantic extraction for images is an urgent problem and is applied in many different semantic retrieval systems. In this paper, a semantic-based image retrieval (SBIR) system is proposed based on the combination of growth partitioning tree (GP-Tree), which was built in the authors’ previous work, with a self-organizing map (SOM) network and neighbor graph (called SgGP-Tree) to improve accuracy. For each query image, a similar set of images is retrieved on the SgGP-Tree, and a set of visual words is extracted relying on the classes obtained from mask region-based convolutional neural networks (R-CNN), as the basis for querying semantic of input images on ontology by simple protocol and resource description framework query language (SPARQL) query. The experiment was performed on image datasets, such as ImageCLEF and MS-COCO, with precision values of 0.898453 and 0.875467, respectively. These results are compared with related works on the same image dataset, showing the effectiveness of the methods proposed.

Interaction between Hygroscopic Seeding and Mixed-Phase Microphysics in Convective Clouds

Abstract Intentional release of hygroscopic particles, or seeding, in convective clouds is one of the postulated methods to artificially enhance rainfall. Motivated by the general uncertainty in the underlying physics, this work employs a large-eddy simulation code together with a detailed aerosol–cloud microphysics model to investigate the conditions and processes conducive to seeding in the United Arab Emirates. Mixed-phase processes are identified as the main source for rainfall in convective clouds in this area owing to the continental aerosol characteristics and a high cloud-base altitude relatively close to the freezing level. Subsequently, our model experiments highlight the importance of mixed-phase processes in mediating the effects of hygroscopic seeding on rainfall as well. The seeding particles acted to accelerate riming by increasing the number of large droplets taken above the freezing level by the convective updrafts. The rime fraction was increased by up to 15%, which promotes the growth of the frozen hydrometeors, eventually leading to enhanced rainfall via melting. The peak enhancement in surface rainfall was up to 20%–30%, although this is almost certainly an overestimation relative to real-world operations because of the simplified description of the seeding in the model. The strongest rain enhancement was obtained with a high background aerosol concentration of approximately 4500 cm−3, whereas reduced aerosol resulted in weaker enhancement. The latter case showed an overall higher rime fraction indicating an already efficient precipitation formation process, which suppressed the seeding-induced enhancement. The conclusions of our work encourage more careful consideration of the mixed-phase processes in quantifying the hygroscopic seeding effects in continental convective clouds.

On the validity of the classical plasma conductivity in capacitive RF discharges

The plasma conductivity is an important input parameter for various plasma models. It is typically obtained from a simplified version of the electron momentum balance equation, where only a single inertia term and a simplified description of the collisional momentum transfer are included. The electric field is assumed to be a harmonic function of the driving frequency, higher harmonics of the current and spatial variations are neglected. Through particle-in-cell/Monte Carlo collision (PIC/MCC) simulations and analysis of the electric field generation based on velocity moments of the Boltzmann equation, the validity of this classical model is studied in capacitively coupled plasmas (CCPs). We find that these assumptions/simplifications result in significant inaccuracies of the conductivity in many cases. In single frequency CCPs, a deviation of more than an order of magnitude from the effective PIC-conductivity obtained from the simulations is found at low pressures in the discharge center and at the maximum sheath edge. In the center, this deviation is caused by neglecting the temperature gradient term in the momentum balance equation and adopting an approximation of the Ohmic term in the classical model, while at the maximum sheath edge it is induced by neglecting the density gradient term that accounts for the effect of the ambipolar electric field. The inaccuracy in the discharge center is reduced at higher pressures where the Ohmic term dominates and the approximations made in the classical model are more applicable. Better performance of the classical model is also found under conditions at which the inertia term included in the model plays an important role. Generally, neglecting higher harmonics of the current and spatial variations of plasma parameters is found to cause strong inaccuracies. Thus, the classical model can result in an inaccurate calculation of the power absorbed by electrons. Our results indicate that its applicability must be evaluated for a given set of conditions before using it to avoid introducing errors to plasma models.

A simplified intragranular description of dislocation density heterogeneities to improve dynamically recrystallized grain size predictions

In current mesoscopic mean-field and full-field models, nucleation of recrystallized grains remains poorly described compared to the physical complexity of the phenomenon, leading to noticeable discrepancy with regards to the size of recrystallized grains. In the present work, a simplified intragranular description of dislocation density heterogeneities is introduced in a recrystallization model in order to improve recrystallized grain size predictions. A detailed material-dependent model parameters identification procedure is provided and discussed. Experimental microstructure evolutions of an Inconel 718 Ni-base superalloy are compared to the model predictions as a validation case.

Toric promotion

This article introduces toric promotion as a cyclic analogue of Schützenberger’s promotion operator. Toric promotion acts on the set of labelings of a graph G G . We discuss connections between toric promotion and previously-studied notions such as toric posets and friends-and-strangers graphs. Our main theorem provides a surprisingly simple description of the orbit structure of toric promotion when G G is a forest.

Simplified Numerical Model for Transient Flow of Slurries at Low Concentration

Rapid transients are particularly dangerous in industrial hydro-transport systems, where solid-liquid mixtures are transported via long pressure pipelines. A mathematical description of such flow is difficult due to the complexity of phenomena and difficulties in determining parameters. The main aim of the study was to examine the influence of the simplified mixture density and wave celerity description on satisfactory reproduction of pressure characteristics during the transient flow of slurry at low concentrations. The paper reports and discusses the selected aspects of experimental and numerical analyses of transient slurry flow in a polyethylene pipe. The experiments were conducted by using the physical model of a slurry’s transportation pressure. The aim of the experiments was to determine the wave celerity during a transient flow in slurries. A low concertation of slurries, which was used during experiments, is typical for one of the biggest slurry networks in Poland. A comparison of the effects of different wave celerity descriptions was performed. The research reported that the theoretical formulas for slurry wave celerity and mixture density were not sufficiently accurate to obtain satisfactory compliance between calculations and observations. To improve the model, the experimental values of wave celerity and the concept of equivalent mixture density have been applied to indirectly consider the influence of variable mixture parameters. With such modifications, the calculated pressure characteristics in all analyzed episodes demonstrated satisfactory compliance with observations. The simplified approach proved to be effective in properly reproducing the intensity and frequency of rapid pressure changes.