Rheologica Acta最新文献

{"title":"Shear jamming and nonlinear rheology of chocolate suspensions","authors":"Michel Orsi,&nbsp;Veeraj Shah,&nbsp;Mahesh Padmanabhan,&nbsp;Thomas Curwen,&nbsp;Jeffrey F. Morris","doi":"10.1007/s00397-026-01546-x","DOIUrl":"10.1007/s00397-026-01546-x","url":null,"abstract":"<div><p>We experimentally investigate the rheology of dark chocolate pastes in both industrially relevant pre-refined form and simplified model systems. Steady and oscillatory shear experiments reveal yielding, pronounced shear-thinning, and stress-dependent hysteresis governed by solid loading. Fitting the viscosity data with the Maron-Pierce model provides stress-dependent maximum flowable fractions <span>(phi _mathrm{{m}}(sigma ))</span>, defining yield loci in the <span>((phi , sigma ))</span> plane. Their variation with stress quantifies the coupled roles of friction and adhesion in setting flow limits. Large-amplitude oscillatory shear tests characterize transitions from elastic to viscous behavior and identify distinct recovery pathways near jamming. Contact-stress decomposition separates hydrodynamic and frictional contributions, confirming that adhesive contact networks dominate stress transmission in pre-refined pastes. These results establish chocolate pastes as dense, adhesive suspensions whose flow is controlled by the interplay of friction and adhesion, offering quantitative benchmarks for constitutive modeling and linking chocolate processing to the broader physics of constraint rheology.</p></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 2","pages":"185 - 204"},"PeriodicalIF":3.0,"publicationDate":"2026-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of interstitial fluid viscosity on the vibrational response of particle-fluid mixtures","authors":"Amir Kafaei,&nbsp;Louis Gosselin,&nbsp;Houshang Alamdari,&nbsp;Seyed Mohammad Taghavi","doi":"10.1007/s00397-025-01542-7","DOIUrl":"10.1007/s00397-025-01542-7","url":null,"abstract":"<div>\u0000 \u0000 <p>Carbon anodes used in the Hall-Héroult process for aluminum production are manufactured by applying vertical vibration in the vibro-compaction stage to improve homogeneity and density. To investigate the effect of fluid viscosity on this stage, we prepared model mixtures of coke particles with glycerin–water fluids of varying viscosities, poured them into a transparent vessel, subjected them to vertical vibration, and tracked the bulk surface profile with an ultra-high-speed camera. Higher-viscosity mixtures formed bulks with larger angles of repose due to stronger cohesive forces. Consequently, after vibration, these mixtures compacted more slowly and less uniformly, requiring more time to stabilize. This resistance to compaction stems from a stronger cohesive network, created by viscous and capillary forces that resist particle movement and rearrangement. At the same time, this network helps viscous mixtures transmit vibration energy more effectively, causing the bulk surface to oscillate with larger amplitude.</p>\u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 3","pages":"255 - 273"},"PeriodicalIF":3.0,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integral fractional viscoelastic models in SPH: LAOS simulations versus experimental data","authors":"Luca Santelli,&nbsp;Adolfo Vázquez-Quesada,&nbsp;Aizeti Burgoa,&nbsp;Aitor Arriaga,&nbsp;Rikardo Hernandez,&nbsp;Marco Ellero","doi":"10.1007/s00397-025-01533-8","DOIUrl":"10.1007/s00397-025-01533-8","url":null,"abstract":"<div><p>The rheological behaviour of a polymer was investigated by performing numerical simulations in complex flow and comparing them to experiments. For our simulations, we employed a Smoothed Particle Hydrodynamics scheme, utilising an integral fractional model based on the K-BKZ framework. The results are compared with experiments performed on melt-state isotactic polypropylene under medium and large amplitude oscillatory shear. The numerical results are in good agreement with the experimental data, and the model is able to capture and predict both the linear and the non-linear viscoelastic behaviours of the polymer melt. Results show that equipping SPH with an integral fractional model is a promising approach for the simulation of complex polymeric materials under realistic conditions.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"64 12","pages":"691 - 707"},"PeriodicalIF":3.0,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentation and yield stress of magnetorheological fluids; challenges and new directions","authors":"Rami Yazeed Khaleel Mousa,&nbsp;Mahmoud Z. Ibrahim,&nbsp;A. Hayyan,&nbsp;Hanee F. Hizaddin","doi":"10.1007/s00397-025-01536-5","DOIUrl":"10.1007/s00397-025-01536-5","url":null,"abstract":"<div><p>Magnetorheological fluids (MRFs) are a class of smart materials that exhibit a rapid and reversible change in rheological properties when external magnetic field is applied. Despite their potential, sedimentation of magnetic particles, and off-state viscosity, hinder their widespread and adoption in industrial applications. Additionally, increasing the yield stress would expand the application of MRF in wider sectors. Addressing these limitations has become a key focus of research in the field. Several approaches have been discussed such as the use of nanoparticle additives, coatings, and alternative MRF compositions for the stabilization and strengthening of MRFs. While these methods have demonstrated partial success, trade-offs between key parameters, such as stability and yield stress, remain an ongoing challenge. By consolidating insights from recent advancements, this review highlights the progress made and identifies new directions for future research. The goal is to provide a better understanding of the techniques and strategies that researchers have developed to refine MRF performance and expand their practical applications.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 2","pages":"113 - 151"},"PeriodicalIF":3.0,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tuning polymer solution elasticity for electrospinning: effects of molecular weight distribution and elastic doping","authors":"Étienne J. Beaudoin,&nbsp;Ricardo J. Zednik,&nbsp;Nicole R. Demarquette","doi":"10.1007/s00397-025-01541-8","DOIUrl":"10.1007/s00397-025-01541-8","url":null,"abstract":"<div><p>Electrospun nanofibers are used in a wide range of applications, from filtration to biomedical scaffolds, yet their successful formation relies on carefully tuned polymer solution properties. Among these, extensional elasticity plays a central role in stabilizing the fluid jet against capillary breakup. While increasing solution viscosity can modestly delay thinning, it is the presence of entangled high–molecular-weight chains that provides the cohesive elastic stresses needed to sustain a continuous filament until solidification. In this work, the influence of molecular weight distribution (MWD), matrix viscosity, and long-chain content on extensional rheology and electrospinnability was investigated using blends of poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO). Shear viscosity and filament thinning dynamics were characterized using rotational rheometry and a custom-built capillary breakup extensional rheometer (CaBER). Initial comparisons confirmed that low molecular weight PEG, despite its high shear viscosity, failed to produce fibers due to the absence of entanglements and extensional elasticity, whereas entangled high molecular weight PEO readily formed uniform nanofibers. MWD was systematically broadened at constant weight-average molecular weight by blending PEO samples of different molecular weights, which increased CaBER-measured relaxation times and led to fibers with larger diameters. Subsequent experiments with Boger-type fluids revealed that shear viscosity alone did not correlate with electrospinning behavior, while relaxation time measured by CaBER remained predictive. Increasing the background matrix viscosity further enhanced extensional elasticity by slowing chain relaxation and filament thinning. Finally, a practical demonstration of elastic doping showed that adding a trace amount of long-chain PEO to an otherwise unspinnable PEG matrix enabled fiber formation and achieved a fivefold increase in polymer throughput. Together, these results establish extensional relaxation time as a robust predictor of electrospinnability and demonstrate that the decoupling of matrix viscosity and chain entanglement offers a versatile strategy for designing high-yield nanofiber formulations.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 3","pages":"209 - 221"},"PeriodicalIF":3.0,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental validation of a magnetorheological fluid activation flow CFD analysis","authors":"Stephen G. Sherman,&nbsp;Min Mao,&nbsp;Young T. Choi,&nbsp;Norman M. Wereley","doi":"10.1007/s00397-025-01540-9","DOIUrl":"10.1007/s00397-025-01540-9","url":null,"abstract":"<div><p>Magnetorheological (MR) fluid-based devices operating at high speeds exhibit a phenomenon termed “high-speed yield force falloff,” characterized by a decrease in the force difference between field-on and field-off states with increasing velocity. This behavior, observed in various applications, contradicts predictions from existing simplified force models that assume constant yield force and employ oversimplified one-dimensional fluid dynamics. Consequently, these models become inaccurate at high speeds due to the increased nonlinearity of the fluid dynamics. This study validates a previously developed two-dimensional computational fluid dynamics (CFD) model, the “activation flow model,” against experimental data obtained from a high-speed MR impact damper. The model accurately predicts the observed yield force falloff, confirming that the primary cause is momentum flux changes within the fluid’s plug region. These findings demonstrate the activation flow model’s potential for accurately predicting high-speed MR device performance, enabling a more robust design of MR impact dampers.</p></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 3","pages":"275 - 285"},"PeriodicalIF":3.0,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-025-01540-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiscale thermal degradation of phas: kinetic and rheological analysis across processing and decomposition regimes","authors":"Hadis Torabi,&nbsp;Hadis Zarrin,&nbsp;Ehsan Behzadfar","doi":"10.1007/s00397-025-01538-3","DOIUrl":"10.1007/s00397-025-01538-3","url":null,"abstract":"<div><p>The thermal degradation of biopolymers limits their industrial and biomedical applications due to poor stability near processing temperatures. This study integrates thermorheology and thermoanalytical techniques to investigate the multiscale degradation behavior of three polyhydroxyalkanoates (PHAs): poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). Rheological functions were used to track structural changes during processing. Properties such as mass loss and derivative thermogravimetric curves were monitored to obtain perception of degradation behaviour at decomposition temperature. The findings revealed distinct degradation behaviors across processing and decomposition regimes. In the processing temperature range (160–210 °C), PHBH exhibited the highest resistance to thermal degradation. In contrast, at higher decomposition temperatures (&gt; 250 °C), PHB and PHBV displayed higher activation energies. This combined methodology links structural evolution, degradation mechanisms, and macroscopic flow, providing a unified framework for assessing thermal stability of PHA and can be extended to other biodegradable polymers for process optimization and material design.</p></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 3","pages":"223 - 239"},"PeriodicalIF":3.0,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rheological response of whey protein deposits forming under shear in concentrated conditions","authors":"Margot Grostete,&nbsp;Jeehyun Lee,&nbsp;Françoise Boissel,&nbsp;Maude Jimenez,&nbsp;Romain Jeantet,&nbsp;Luca Lanotte","doi":"10.1007/s00397-025-01534-7","DOIUrl":"10.1007/s00397-025-01534-7","url":null,"abstract":"<div><p>Dairy fouling consists in the accumulation of whey proteins and minerals on equipment walls. While heat-induced protein denaturation is a primary cause, fouling also occurs below the denaturation threshold (≈ 70 °C). This leads to a renewed interest in other driving forces influencing fouling mechanisms. In this wake, this study investigates the role of shear on the formation of whey protein deposits under sub-denaturation temperature and concentrated conditions. We compared morphology and rheological behavior of shear-induced and unsheared structures formed at 15 and 20 wt% protein concentrations. While unsheared gel-like deposits were compact and stiff, shear led to the formation of weaker, more porous, and highly crosslinked structures. This effect was more pronounced at higher concentrations, where shear counteracted heat-induced aggregation, resulting in an alternative structural organization. These findings provide new insights not only into whey protein gelation but also into dairy fouling mechanisms, highlighting a concentration-dependent shear effect.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"64 12","pages":"745 - 755"},"PeriodicalIF":3.0,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-025-01534-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leveraging viscoelasticity for load enhancement in rotating contacts","authors":"Humayun Ahmed,&nbsp;Luca Biancofiore","doi":"10.1007/s00397-025-01529-4","DOIUrl":"10.1007/s00397-025-01529-4","url":null,"abstract":"<div>\u0000 \u0000 <p>Tribological components such as bearings and gears sustain a tremendous external load and operate at high relative speeds. For hydrodynamically lubricated contacts, subject to these extreme conditions, the lubricating fluid film exhibits non-Newtonian characteristics. In particular, when the ratio of fluid relaxation time to the flow residence time, i.e., the Deborah number (<span>(varvec{De})</span>), becomes appreciable, viscoelastic effects emerge. In this work, we model the effect of viscoelasticity using the viscoelastic Reynolds equation (VR) in cylindrical coordinates under the ultra-dilute limit in which the solvent concentration in terms of viscosity is larger than the polymeric contribution. As such, the velocity field remains Newtonian and the polymer stress constitutive relation is further simplified. We examine the effect of fluid viscoelasticity on the load carrying capacity for two geometries; (i) a conical configuration (that could be aligned or misaligned) and (ii) a flat surface embedded with different kind of textures. Our results show that viscoelasticity can enhance the load carrying capacity in both cases. Small errors in alignment strongly affect the trend in the load versus <span>(varvec{De})</span> and a strong nonlinear trend emerges exhibiting load both saturation and diminishment. Introducing pockets in the surface further improves the load bearing capability beyond the Newtonian values. However, numerical simulation of such textured configurations is challenging and, unlike the inclined asymmetric cone, large values of the Deborah number could not be reached.</p>\u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"64 12","pages":"729 - 743"},"PeriodicalIF":3.0,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-025-01529-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Special issue devoted to the XVIII Italian society of rheology conference (SIR 2024)","authors":"Sergio Caserta,&nbsp;Claudia Carotenuto,&nbsp;Gaetano D’Avino,&nbsp;Giovanna Tomaiuolo","doi":"10.1007/s00397-025-01539-2","DOIUrl":"10.1007/s00397-025-01539-2","url":null,"abstract":"","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"64 12","pages":"687 - 689"},"PeriodicalIF":3.0,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146027096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}