Mixing Properties Research Articles

A note on the mixed properties of the nominal structure in Polish

Abstract The aim of this paper is to highlight certain similarities between Polish and Bulgarian with respect to the selected NP/DP criteria compiled by Bošković (2012. On NPs and clauses. In Günther Grewendorf & Thomas Ede Zimmermann (eds.), Discourse and grammar: From sentence types to lexical categories, 179–242. Berlin: De Gruyter). In the course of the discussion, Negative Raising with idioms and quantifier – negation interaction, definite/indefinite contrasts in the context of sub-extraction, as well as exhaustive presupposition are taken into consideration. On the basis of the data, I put forward an analysis of the Polish facts which draws upon Tasseva-Kurktchieva and Dubinsky’s (2018. On the NP/DP frontier: Bulgarian as a transitional case. In Steven Franks, Virinda Chidambaram, Brian Joseph & Ilyana Krapova (eds.), Studies in Bulgarian Morphosyntax in Honor of Catherine Rudin, 287–312. Bloomington, IN: Slavica) account of the DEF(initeness) feature on the D head (which they use to argue for Bulgarian as a ‘weak’ DP language). Despite certain similarities between the two languages, Polish actually seems to resemble English in terms of the specific coding of this feature. The analysis suggests that (unlike in Bulgarian) DEF on D in Polish is not intrinsically valued (+int, +val), but rather receives a specific value in the course of the syntactic derivation.

Symbolic Dynamics and Topological Complexity in Discrete Dynamical Systems

This paper presents a comprehensive review of symbolic dynamics and topological complexity in the context of discrete dynamical systems. We explore the fundamental concepts, recent theoretical advancements, and emerging applications of these powerful analytical tools. Symbolic dynamics, which represents system trajectories as sequences of symbols, provides a bridge between continuous dynamics and discrete mathematics. We discuss its origins, development, and key theorems, emphasizing its role in studying long-term behavior and chaos. Topological complexity, closely related to topological entropy, offers a measure of the intricacy of orbits within a dynamical system. We examine various methods for computing and analyzing topological complexity, highlighting its significance in understanding chaotic behavior and mixing properties. The interplay between symbolic dynamics and topological complexity is thoroughly investigated, demonstrating how symbolic representations facilitate the computation of topological entropy and the study of structural stability. We present recent applications of these concepts in diverse fields, including information theory, cryptography, biological systems, and ergodic theory. Case studies illustrate the practical utility of symbolic dynamics and topological complexity in solving real-world problems. Additionally, we discuss open problems and future research directions, emphasizing the potential for further theoretical developments and novel applications. This review aims to provide both an accessible introduction for newcomers and a valuable resource for established researchers in the field of discrete dynamical systems. By synthesizing current knowledge and highlighting key challenges, we hope to stimulate further research and cross-disciplinary collaborations in this rich and evolving area of mathematics.

Strong consistency of parameter estimation for the CIR integrated diffusion process with long-span high-frequency data

In this article, we utilize the contrast function of the integrated diffusion process to derive parameter contrast estimators for the Cox-Ingersoll-Ross integrated diffusion process and discuss the asymptotic properties of the estimators using the mixing properties of the process. We first give the tail probability exponential inequality of the mixing long-span high-frequency data. Then, applying this inequality, we prove the strong consistency of the contrast estimators for the drift parameters and diffusion parameter of the CIR integrated diffusion process. In order to obtain these asymptotic properties, we require relatively low order r of the negative power moment E | X t − 1 | r of the diffusion process. In the existing literature, r > 9 is required in order to obtain weak consistency of the estimators. However, in our theorems, only r > 2 is required for the strong consistency of the diffusion parameter estimator, while r > 4 for the strong consistency of the drift parameter estimators. In the simulation analysis, we use the Euler discretization algorithm and the Milstein discretization algorithm, and the results show that the optimal sampling interval is around n − 1 / 3 . We use the daily log price data of the CSI 300 Index to estimate the CIR integrated diffusion model and construct a Bootstrap prediction model for the log price. The results show that the model has a good predictive performance.

Insights into the functional properties of a natural free amino acid mix: Effect on growth performance, nutrient metabolism, and immune response in a carnivorous fish, Asian seabass (Lates calcarifer)

Dietary supplements containing a functional feed additive have been shown to be beneficial to fish and shellfish aquaculture. However, the functional properties of aquafeed formulations have rarely been reported in fish. This study aimed to investigate the effects of natural free amino acid mix (FAAM) supplementation as a functional solution on the growth performance and nutrient utilization in a carnivorous fish, Asian seabass (Lates calcarifer). Five isonitrogenous and isolipidic diets were prepared with graded supplementation levels of FAAM at 0 % (control group), 0.25 %, 0.50 %, 0.75 %, and 1.0 %, denoted as FAAM0, FAAM0.25, FAAM0.5, FAAM0.75, and FAAM1.0, respectively. The experimental fish were fed different dietary FAAM supplementations to apparent satiation twice daily for eight weeks. Significant improvements were observed in the growth performance of fish among the five groups (P < 0.05). Fish fed with FAAM0.75 displayed significantly increased activities of lysozyme, myeloperoxidase, catalase, and glutathione peroxidase (P < 0.05). The activities of digestive enzymes, including amylase, protease, and lipase, were enhanced by the supplementation of FAAM in the feed (P < 0.05), especially for the groups that contained more than 0.5 % FAAM in the feed. Furthermore, the morphological profile of the intestinal tract, including the mucosal fold height, width, thickness, and goblet cell, increased in fish fed with FAAM at 1.0 % (P < 0.05). Moreover, FAAM supplementation in diets not only modulated the expression of immune-related genes (glutathione peroxidase (GPx), complement (C)3, C4, and C-reactive protein) in the liver but also positively impacted the growth-ralated genes, including growth hormone (GH), GH receptor (GHR), insulin-like growth factor I (IGF-I), and IGF-II. In addition, the amounts of monounsaturated fatty acids (mainly oleic acid (C18:1n9c)) and polyunsaturated fatty acids-especially γ-linolenic acid (C18:3 n6) and α-linolenic acid (C18:3n3)-increased in fish fed with diets containing FAAMs (P < 0.05). Interestingly, the diets supplemented with FAAMs also had a positive effect on the economic indices in terms of revenue-to-cost ratios. These findings provide a scientific basis for the application of FAAMs as a functional solution that can be used in feed formulations for Asian seabass.

A novel design of three‐dimensional/unidirectional hybrid composites to balance in‐plane and interlaminar mechanical properties

AbstractThe working condition of the rail transit components such as bogies is complicated, so the high comprehensive performance of composite parts is desperately required. However, existing pure three‐dimensional braided or laminated composites have been unable to satisfy the cooperative demand of in‐plane and interlaminar properties. In this paper, a novel design of three‐dimensional braided/unidirectional (3D/UD) hybrid composite is proposed to balance the in‐plane (tensile, compression, bending), interlaminar (interlaminar shear, low‐speed impact) properties of the composite. The effects of different 3D/UD mixing ratio and layup sequence on the mechanical properties and damage mechanism of hybrid composites were studied by the parametric analysis of the experimental test results, and the comprehensive mechanical properties of the hybrid structure were optimized by COPRAS evaluation method. The results show that the larger the proportion of unidirectional layer, the better the mechanical property in‐plane, but the worse interlayer property. In addition, the change of layup sequence induces a complex nonlinear relationship between 3D/UD mixing ratio and mechanical properties. Combined with microscopic failure characterization results, it is found that the sandwich structure and the addition of uniformly distributed interfacial layer can improve the mechanical properties of the hybrid composite. The optimization results show that the sandwich structure hybrid composite UD6/3D/UD6 with the best balance between in‐plane and interlaminar properties was selected by COPRAS. Compared with pure 3D composites, the comprehensive mechanical properties of UD6/3D/UD6 are increased by 53.9%, which provides a reference for the structural design of hybrid composites in the future.Highlights A novel design of 3D/UD hybrid composite is proposed to balance the in‐plane and interlaminar properties. The influence regularity of 3D/UD mixing ratio and layup sequence on properties of hybrid composites were obtained. The mixing failure mechanism of interlayer and in‐plane was revealed. The optimal structure UD6/3D/UD6 under complex working conditions was obtained by COPRAS.

Regulation of baking quality and starch digestibility in whole wheat bread based on β-glucans and protein addition strategy: Significance of protein-starch-water interaction in dough

Whole wheat bread has high nutritional value but is characterized by inferior quality and a high glycemic index. Studies have shown that adding β-glucans and protein can improve bread quality. This study investigated the effects of added oat β-glucan, barley β-glucan, or yeast β-glucan on protein synergy and whole wheat dough and bread quality. The mixing properties, rheological properties, and scanning electron microscopy observations showed that the addition of β-glucan promoted the formation of gluten networks, while the synergy between the wheat proteins and β-glucan resulted in a more robust and stable gluten network and a stronger physical starch envelope. Rapid visco-analysis and thermal property evaluations showed that β-glucan addition inhibited the thermal degradation, gelatinization, and retrogradation of starch. Based on the bread quality results, it was found the β-glucan could cause some damage to the bread baking quality. For example, the hardness of samples with oats, barley, and yeast increased to 881.69 g, 952.97 g, and 631.75 g, respectively, compared to samples without β-glucan (317.49 g), whereas the inclusion of yeast β-glucan proved to be less detrimental. Protein and β-glucan both reduced starch digestion to some degree, and showed better synergistic effects, with the lowest estimated glycemic index of 70.08 observed in bread containing added yeast β-glucan and protein. Therefore, yeast β-glucan and protein mixtures could be selected as viable formulations for enhancing the quality of whole wheat bread.

Adhesion property of municipal solid waste incinerator bottom ash and limestone with asphalt based on surface energy theory

ABSTRACT The aim of this paper is to investigate the adhesion of municipal solid waste incinerator bottom ash (MSWIBA) and limestone to asphalt using the principles of surface energy theory. MSWIBA asphalt mixes are known for their satisfactory water stability, with adhesion being a crucial factor, as demonstrated in previous freeze-thaw splitting tests. Contact angles of ground MSWIBA and limestone were measured using a capillary rise test, eliminating the influence of material surface structure. Subsequently, adhesion work and spalling work were calculated to correlate with water-induced damage. The results showed that the sequence of adhesion work was fine MSWIBA > limestone > coarse MSWIBA, while the sequence of spalling work was coarse MSWIBA > limestone > fine MSWIBA. The adhesion of MSWIBA asphalt mixes was evaluated using the water boiling test image method to validate the findings of surface energy theory. In both asphalt tests, the spalling rate followed this sequence: coarse MSWIBA > limestone > fine MSWIBA. The Adhesion index ER ranked as follows: ER Fine MSWIBA > ER limestone > ER coarse MSWIBA. These results suggest that the water stability of MSWIBA asphalt mixes is influenced by the surface energy of the components. Consequently, indices derived from surface energy theory can be applied in formulating and predicting the properties of MSWIBA asphalt mixes.

Pukekauri farm – snapshots from a sustainability journey

Pukekauri Farm is a 295 ha mixed livestock hill country property in the western Bay of Plenty. Over the last 20+ years the owners have been on a development journey with a focus on the multiple dimensions of sustainability – economic, environmental, and social. This paper seeks to document that journey, with supporting resource, production, financial and environmental data to quantify progress. Some of the most useful tools have included high quality forage crops, deferred grazing, sheep genetics, accounting software and paddock-scale soil and water resource maps. Key lessons include the value of knowledge networks and modelling tools, the power of a farm plan for optimising land use and management, the importance of both profitability and grants to underwrite development investment, and the emergence of secondary benefits from decisions focused on system-wide improvement. Over 20 years, despite areduction in grazed area of 20%, meat production has increased by 16%, EBITR/ha has increased by 6%, modelled net greenhouse gas emissions have declined by 60% and modelled N leaching has declined by 29%. Overall, the farm is easier to manage and more pleasant to dwell in.

Effect of alkali activated limestone-silica fume blended precursor on performance enhancement of recycled aggregate concrete

The utilization of Recycled Aggregates (RA) from Construction and Demolition (C&D) waste, has been reported to be an efficient way of dealing with the environmental issues encountered by our planet nowadays. However, due to the poor quality of RA, its incorporation in high – grade civil engineering applications been limited. It is essential that adequate process of treatment methods be incorporated into the production of RA to enhance its properties and optimize its use. This study is carried out to determine the effects of an alkaline NaOH activated by limestone powder (LSP) and silica fume (SF) to improve the properties of various concrete mixes produced with either recycled concrete aggregate (RCA), or recycled cement block aggregate (CBA). Fifteen mixes were designed to examine the effects of different parameters, RA replacement levels, various w/c ratios and different enhancement methods on the properties of recycled aggregate concrete (RAC). The study examined the effects of the proposed enhancement method on the physical characteristics of RCA and CBA. Compressive strength, splitting tensile strength, flexural strength, pull-out, and water absorption of the different concrete mixes were measured to determine the effectiveness of the enhancement method proposed. The enhanced RAC produced by CBA and RCA showed an increased 28-day compressive strength at 0.35 w/c ratio of up to 51 MPa and 44 MPa, respectively, suitable for structural applications. The flexural strength, tensile splitting strength, and bonding strength values at 0.35 w/c ratio of the enhanced RAC produced with treated CBA were 28%, 6%, and 8% higher than that of the RAC produced with treated CBA. Whereas, the flexural strength, tensile strength, and bonding strength of the enhanced RAC produced with treated RCA were 1%, 3%, and 5% higher compared to the RAC produced with treated RCA. The improved mechanical performance of the enhanced RAC produced by CBA or RCA was attributed to the effects of the geopolymer solution treatment in filling and sealing the voids and gaps on the CBA and RCA surface, leading to a better packed structure, reducing the water absorption, and improving the aggregate impact value. The treatment technique proposed can be a powerful tool for promoting the use of RA in the construction industry and expanding its application.

Evaluating the Printability and Rheological and Mechanical Properties of 3D-Printed Earthen Mixes for Carbon-Neutral Buildings

This research delves into the vital aspect of adapting local soil properties for 3D printing and explores the mix design of collected earthen materials to tackle challenges in printability, shrinkage, and mechanical properties. Initially, soil samples from six local sites underwent characterization based on Atterberg’s limits, focusing on identifying the most suitable high-clay-content soil. The soil with a higher clay content was used for further study, and its clay type was determined using an X-ray diffraction (XRD) analysis, revealing the presence of 49% kaolinite, 15% nontronite, and 36% illite clay minerals. Four earthen mixes were designed by including stabilizers (i.e., hydrated lime), natural pozzolana, and degradable natural fibers (wheat straw fiber). Subsequently, the study examined their rheological properties, shrinkage behavior, compressive and flexural strength, and printability (including extrudability and buildability). The pure soil mixture excelled in printing quality and mechanical strength, but suffered from cracking and drying shrinkage due to its high nontronite clay content. The existence of 15% nontronite clay mineral in the soil resulted in significant shrinkage and extensive cracking of specimens. However, fiber incorporation effectively mitigated large cracks and reduced shrinkage to as low as 2.6%. Despite initial expectations, introducing lime and pozzolana as soil stabilizers did not improve strength, prevent shrinkage, or improve the printability of soil mixes.

Tracer concentration mapping in a stream with hyperspectral images from unoccupied aerial systems

The release of anthropogenic chemicals to streams, stemming from contaminated sites, agriculture, urban sources, or accidental input, represents a significant threat to water resources and thus the health of humans and aquatic ecosystems. Predicting the transport and fate of chemicals is critical to quantifying contaminant concentrations and developing environmental quality standards (EQS). Tracer tests are a well-established tool for such hydrological investigations in various aquatic systems. In stream settings, the experiments have predominantly investigated longitudinal mixing and flow velocities by measuring the tracer concentration in a few discrete locations; few studies have focused on the transverse mixing properties. Recent progress in hyperspectral remote sensing from Unoccupied Aerial Systems (UAS) allows advancing the two-dimensional monitoring of tracer tests, by mapping the tracer concentration with a high spatial resolution in narrow streams with difficult accessibility. So far, such methods have mainly been demonstrated in controlled settings or in ocean waters, but rarely in optically complex streams. In this study, we evaluated the performance of a miniaturized hyperspectral imaging system and a consumer grade camera onboard a UAS, to map the concentration of the fluorescent tracer Rhodamine WT in a stream impacted by a contaminated site. In order to estimate tracer concentrations from the remotely sensed data, a ratio of the red and blue band was used for the RGB camera, while a vector-based method, estimating the spectral angle in regards to a reference spectrum, was applied for the continuum-removed hyperspectral data. The RGB camera performed well only in sections of the stream exposed to direct sunlight (R2: 0.83; nRMSE: 10.2%), failing to map the concentration in all locations, which included areas where direct sunlight was blocked by riparian trees (R2: 0.17; nRMSE: 26.19%). In contrast, the advanced spectral information allowed the hyperspectral- system to map the concentration well in all sections of the stream (R2: 0.78; nRMSE: 13.35%), regardless of illumination changes. This demonstrated the advantage of hyperspectral imaging systems for measuring water-leaving irradiance in hundreds of contiguous narrow spectral bands that also allow detecting finer absorption and emission features. The approach described here could help to improve the knowledge of contaminants mixing in streams, i.e. to predict the location of fully transverse mixing for contaminated sites discharging to streams via groundwater-surface water interactions, as well as general assumptions behind mixing and dilution models.

Influence of multi-stage processing and mechano-chemical treatments on the hydration and microstructure properties of recycled aggregate concrete

On account of the shortage of naturally occurring coarse aggregate, recycled aggregate (RA) made from crushed concrete debris is now used in the construction industry. With this rise in the utilisation of recycled aggregate in the construction sector, there has been extensive research into ways to improve its quality. The significant fraction of mortar remains that are left on the RA surface is the primary factor that affects its quality. Concrete made from RA loses strength and mechanical performance due to the attached mortar's increased porosity and water absorption values and the frailer transition region between the new mortar and aggregates. In order to minimise the old cement fractions and increase the quality, this paper studies the effect of concrete incorporating multi-stage processed RA from demolished concrete waste, followed by treatment with mechanical abrasion and sodium silicate immersion. The recycled aggregates were produced through multi-stage jaw crushing, followed by utilising natural aggregate, recycled aggregate, and recycled aggregate obtained after mechanical abrasion, followed by sodium silicate treatment for concrete mix design at various substitution percentages as coarse aggregates. The experimental investigation further progresses with the evaluation of mechanical and durability properties of concrete mixes, which is additionally followed by microstructural studies such as scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDAX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Thermogravimetry-differential thermal analysis (TG-DTA). The outcomes demonstrate that two-stage treatment, such as mechanical abrasion followed by sodium silicate immersion, yields superior-quality RA. Recycled aggregate concrete (RAC) made with these treated aggregates illustrated an increase in workability and density with respect to an untreated RAC mix. Furthermore, comparable strengths in compression, flexure, and tension are found in treated RAC mixes, particularly at 35% replacement levels, with respect to concrete mixes comprised of natural aggregates. A similar trend is detected in the chloride penetration tests and water sorptivity tests. In addition, the microstructural investigation confirmed the formation of additional calcium silicate hydrate for treated RAC mixes, particularly for the 35% substituted RA mix. On the basis of the results, it is suggested that multi-stage jaw crushing followed by treatment through mechanical abrasion and sodium silicate can potentially enhance the mechanical, microstructural, and durability performance of RAC.

Research the Effects of Phase Change Materials on the Properties of Cement

Structural concrete of Mass Concrete of high-rise buildings has a compressive strength usually greater than 35 MPa. It is quite difficult to keep the required Tmax temperature, but the compressive strength and properties of the concrete mix. The phase change materials, when added to the concrete mix, has the effect of lowering the total heat of the mass conctete from 5 ºC to 10 ºC, contributing to reduce the temperature Tmax. At present, in Vietnam, phase change materials are new materials, and there is no research on the effects when used in cement and concrete. The article studies the influence of phase change materials on the properties of cement.

A numerical simulation of high-Reynolds-number opposed impinging wall water jets in a limited field

In the impinging region of opposing jets, strong mixing and significant energy dissipation are observed, but the mixing parameters invariably change with the opposed impinging strength (OIS). In this paper, the ratio of the turbulent kinetic energy (TKE) intensity at the theoretical impinging point to the nozzle exit is defined as the opposed impinging strength. To examine the mixing properties of opposed impinging jets (OIJs) in a limited field under various OIS, a renormalization group k-ε turbulence model is employed to calculate three-dimensional OIJs under various OIS. The nozzle exit diameter is set to 0.6 m, and the inlet velocity is between 0.08 and 8 m/s, so the simulations are performed at Re between 4.8 × 104 and 4.8 × 106. This work focuses on the radial and vertical jets produced after impinging as well as the distribution of the TKE, flow field, and vortices. A thorough investigation reveals that although the OIS of the jets is primarily determined by the degree of jet development, it increases with the Reynolds number. A low OIS results in less mixing in the surrounding water and relatively unconstrained jet generation; however, it also results in limited energy extraction from the fluid. Once the OIS is high, there is more mixing in the surrounding water, and more energy is also lost during impinging. The distribution of vortices in the vortex field is not only influenced by the OIS but is also very closely related to the scale of the limited mixing field.

Novel Structural Aspects of Heavy-Crude-Derived Asphaltene Molecules for Investigating the Crude Mix Processability in Refinery Operation

Summary In this paper, we investigate the role of asphaltenes derived from heavy crudes, which dictates the behavior of crude mix properties for hassle-free downstream refinery operation. Combined characterization techniques such as proton nuclear magnetic resonance (1H-NMR), cross-polarization magic-angle-spinning carbon-13 (CP/MAS 13C)-NMR, heteronuclear single-quantum coherence (HSQC), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) are used for the detailted study of Ratwai and Ras Gharib (RG)-derived asphaltenes to validate their structural role in selecting the optimal crude mix. As per our investigation, when the polyaromatic core of asphaltene structures are less substituted, the availability of aromatic hydrogen is more; it exhibits a stable crude mix as compared to heavy crudes that have more aromatic core substitution, despite the crudes possessing similar asphaltene content and physicochemical properties. This finding is further extended to West Canadian (WC) and Belayim (BL) heavy crudes for operational suitability. In this study, the key feature is to develop a CP/MAS 13C-NMR-based robust and quick characterization technique that could potentially become a prescreening method to assess crude oil compatibility and its various blend processability in the refinery system. Other characterization techniques, such as 1H-NMR, HSQC, FTIR, TGA, and XRD, would corroborate and confirm the reliability of the data obtained by CP/MAS 13C-NMR.

Hydration, Reactivity and Durability Performance of Low-Grade Calcined Clay-Silica Fume Hybrid Mortar

Low-grade calcined clay, due to its low cost, availability and low temperature calcination, has been gaining attention in recent times as a supplementary cementitious material (SCM) in the manufacture of revolutionary building materials to improve the fresh and hardened properties of concrete. Silica fume, on the other hand, has been used, over the years, to improve the performance of concrete due to its reduced porosity and improved transition zone quality. In spite of the individual contribution of these two pozzolans to the strength and durability of concrete, there is a knowledge gap in the properties of ternary blended mixes utilizing calcined clay and silica fume. In this study, the synergistic effect of calcined clay and silica fume on the fresh and hardened properties of cementitious mortar have been investigated. The two pozzolans were used to partially substitute Portland cement to form a ternary blended composite binder having, at a maximum, a replacement of 30% by weight and a varying content of calcined clay and silica fume. The influence of the binary and ternary blended mixes on hydration, pozzolanic reactivity and the mechanical and durability properties of mortar was studied. From the results, partial replacement of cement with 30% calcined clay and silica fume caused significant reductions in the portlandite content of the two hydrated pastes at all curing ages. Drying shrinkage was found to be less severe in the control mortar than the blended cement mixes. Compared to the blended cement specimens, the control suffered the most weight (13.3%) and strength (10%) losses, as indicated by the sulphate resistance test.

Mixed Convective Heat Transfer Characteristics of Graphene Nanofluid Strengthened by Periodically Direction-Switching Electric Field

Abstract Transformer-oil with low thermal conductivity and large viscosity has poor heat dissipation capability, which leads to the thermal drive failure caused by transient overload. To improve its cooling capability, this paper has proposed first the method which combined the periodically direction-switching electric field and graphene nanofluid to enhance the mixed convective heat transfer properties of transformer-oil, and analyzed the effects of switching periods, nanofluid concentration, electric field strength, heat flux, and Reynolds number on mixed convection heat transfer experimentally. The results show that the heat transfer characteristic of transformer-oil is improved up to 52% by the periodically direction-switching electric field and graphene nanofluid. As the switching period decreases, the thermal performance of the suspension is enhanced more significantly. Moreover, by analyzing the heat transfer mechanism, the periodically direction-switching electric field causes the nanoparticles to move reciprocally, repeatedly impacting and breaking the boundary layer of the heat exchange surface to enhance the perturbation, thus enhancing the heat transfer effect. Meanwhile, the predicted correlation has been proposed on the basis of influence factors, which are in good agreement with the experimental data.

Mixing intensification and kinetics of 2,4-difluoronitrobenzene homogeneous nitration reaction in a heart-shaped continuous-flow microreactor

In this study, we first experimentally demonstrated that the homogeneous nitration reaction process in capillary T-micromixers was greatly influenced by the limitations of mixing. Therefore, to improve the mixing effectiveness, we investigated the intensification of liquid mixing in the heart-shaped microreactor. Compared with the capillary T-micromixer, the mixing effectiveness in the heart-shaped microreactor was improved by three orders of magnitude, resulting in a conversion rate of 98.5 % and a reduction in residence time by two orders of magnitude compared to batch reactors. Furthermore, we have established a kinetic model that eliminates interphase mass transfer resistance and verified its accuracy by comparing the calculated values with the experimental ones. The mixing properties in the microreactor were revealed using the Damköhler number, Peclet number, and the mixer effectiveness. These findings contribute to the development of nitration reactions by highlighting the advantages of microreactors in this area and offer guidance for potential applications within the chemical industry.

Probing the physics in the core boundary layers of the double-lined B-type binary KIC 4930889 from its gravito-inertial modes

Context. Stellar evolution models of B-type stars are still uncertain in terms of internal mixing properties, notably in the area between the convective core and the radiative envelope. This impacts age determination of such stars in addition to the computation of chemical yields produced at the end of their life. Aims. We investigated the thermal and chemical structure and rotation rate in the near-core boundary layer of the double-lined B-type binary KIC 4930889 from its four-year Kepler light curve, ground-based spectroscopy, and Gaia astrometry. Methods. We computed grids of 1D stellar structure and evolution models for different mixing profiles and prescriptions of the temperature gradient in the near-core region. We examined the preferred prescription and the near-core rotation rate using 22 prograde dipole modes detected by Kepler photometry of KIC 4930889. We employed a Mahalanobis distance merit function and considered various nested stellar model grids, rewarding goodness of fit but penalising model complexity. Results. We were able to constrain the near-core rotation rate of the pulsator to Ωrot = 0.73−0.06+0.02 d−1. Furthermore, we found a preference for either an exponentially decaying mixing profile in the near-core region or absence of additional near-core mixing, but found no preference among the various options for the temperature gradient in this region. The frequency (co)variances of our theoretical predictions are much larger than the errors on the observed frequencies. This forms the main limitation on further constraining the individual parameters of our models. A combination of spectroscopic, astrometric, binary, and asteroseismic information was used to achieve these constraints. Additionally, non-adiabatic pulsation computations of our best models indicate a need for opacity enhancements to accurately reproduce the observed mode excitation. Conclusions. The eccentric close binary system KIC 4930889 proves to be a promising target to investigate additional physics in close binaries by developing new modelling methods with the capacity to include the effect of tidal interactions for full exploitation of all detected oscillation modes.

Solubility of difluoromethane (R-32) and pentafluoroethane (R-125) in 1-alkyl-3-methylimidazolium tricyanomethanide ionic liquids

The recovery of refrigerant blends and the subsequent separation of value-added hydrofluorocarbons (HFCs) for reuse would help to meet the phase-down in the production of virgin HFCs established by the Kigali Amendment to the Montreal Protocol. The use of ionic liquids (ILs) in extractive distillation processes has become particularly relevant. In this process, the selection of the IL is the core element for a technically and economically feasible design. For this purpose, the absorption of the HFCs difluoromethane (R-32) and pentafluoroethane (R-125), components of the equimassic mixture R-410A, in 1-alkyl-3-methylimidazolium tricyanomethanide ILs was studied. The isochoric saturation method was applied to report vapor-liquid equilibrium data over a temperature range of 283.15–323.15 K and up to 0.9 MPa. These data were fitted accurately to the NRTL activity coefficient model and the Henry's law constants, the activity coefficients at infinite dilution, the enthalpies and entropies of solvation and the thermodynamic mixing properties were calculated. Finally, [C2C1im][tcm] ranked as one of the most selective ILs to date, exhibiting a good R-32 absorption capacity that could make it a valuable solvent for the separation of R-410A by extractive distillation.