Table of Contents
Overview
Definition of Rheology
Rheology is defined as the study of the flow and deformation of matter, primarily focusing on materials in a fluid state, such as liquids and gases, as well as "soft solids" that exhibit plastic flow under applied forces rather than elastic deformation. This branch of physics examines the relationship between stress and deformation, linking a material's intrinsic properties to its overall performance.[4.1] Rheology encompasses the behavior of both viscous and elastic materials, including Newtonian and Non-Newtonian fluids, and is essential for understanding material behavior in various applications, including material design and quality control.[3.1] The field of rheology investigates how materials respond to applied forces, exploring key concepts such as stress, strain, elasticity, and viscosity.[3.1] It employs tools like rheometers to measure the deformation or stress resulting from applied forces, thereby providing insights into the flow and deformation characteristics of materials.[4.1] Rheology has evolved significantly over nearly a century and is now widely applied across multiple disciplines, including the chemical industry, biological engineering, food science, and materials science.[6.1]Importance of Rheology in Various Industries
Rheology plays a crucial role across various industries by influencing the formulation, processing, and performance of materials. In the pharmaceutical sector, rheological properties are vital for understanding the stability of both liquid and semi-solid products. For instance, the viscosity of a nasal spray must be carefully controlled to ensure effective delivery of the active ingredient through spraying.[7.1] Additionally, viscosity significantly impacts drug formulation, manufacturing processes, and drug delivery systems, ultimately affecting therapeutic outcomes and patient compliance.[19.1] In the food industry, rheology is essential for assessing the texture and mouthfeel of products. Shear-thinning behavior, where the viscosity of a fluid decreases under shear strain, is particularly important in food formulation. This property allows for easier processing and improved consumer acceptance, as it can enhance the sensory experience of food products.[15.1] The study of food rheology helps in understanding the physicochemical principles of structuring food materials and their interactions, which is critical for product development.[14.1] Moreover, in materials engineering, rheology informs the design and manufacturing processes of plastics. The cooling stage in injection molding, for example, is influenced by rheological principles, as longer cooling tanks are necessary to ensure adequate heat exchange and maintain high throughput.[8.1] The classification of fluids based on their shear stress and shear rate, such as pseudoplastic and Bingham plastic behaviors, further illustrates the importance of rheology in optimizing material performance.[12.1] In the chemical industry, the management of viscosity is crucial for effective mixing and processing of highly viscous products. Operators must navigate the challenges posed by viscosity effects to prepare complex formulations, which is essential for maintaining product consistency and quality.[18.1] Understanding and controlling viscosity is also critical in the formulation-design space, impacting manufacture, storage, and transportation of materials.[21.1]History
Key Historical Milestones
Rheology, the study of the flow of matter, has a rich history marked by several key milestones. The term "rheology" was coined in 1929 by Professor Eugene C. Bingham, who defined it as "fundamental and practical knowledge concerning the deformation or flow of matter" during the founding of the Society of Rheology.[74.1] Although the formal establishment of rheology as a science occurred in the early 20th century, its foundational concepts can be traced back to earlier figures such as Sir Isaac Newton and Robert Hooke, who contributed to the understanding of material behavior long before the term was introduced.[47.1] The development of rheological models began in earnest in the early 20th century, with significant contributions from Bingham and Markus Reiner, who explored the behavior of polymer materials and established the relationship between a material's composition, structure, and its rheological properties.[46.1] By the turn of the 20th century, scientists recognized the existence of materials that could not be classified strictly as Hookean solids or Newtonian fluids, leading to a broader understanding of material behavior.[75.1] The late 19th and early 20th centuries were characterized by profound societal and technological changes, including the Industrial Revolution, which transformed agrarian societies into industrialized ones. This period of transformation influenced the development of rheological theories, as advancements in science and technology prompted researchers to approach the study of material behavior with new methodologies.[74.1] In the mid-20th century, the rise of materials science and the advent of sophisticated analytical tools further propelled the field of rheology. Notably, researchers like Andrew Jenike made significant strides in powder rheology, introducing essential concepts such as the flow function and cohesive strength, which became critical for understanding powder flow behavior.[76.1]Influential Scientists in Rheology
The foundational principles of rheology can be traced back to the early experiments and theories proposed by influential scientists such as Robert Hooke and Isaac Newton. Hooke's law of elasticity, articulated in the 17th century, established a linear relationship between stress and strain, encapsulated in the phrase "ut tensiosic vis".[65.1] This law laid the groundwork for understanding the behavior of materials under deformation, which is central to rheology. Isaac Newton further advanced the field in the late 17th century with his work "Principia," where he implicitly defined viscosity as the constant ratio of shear stress to shear rate, a principle that is foundational to Newtonian fluids.[67.1] Newton's viscosity law states that the shear stress between adjacent fluid layers is proportional to the velocity gradients between those layers, establishing a critical relationship that is still utilized in fluid mechanics today.[67.1] By the early 19th century, the contributions of scientists such as Navier and Stokes expanded upon these initial concepts, leading to a broader understanding of fluid dynamics and the classification of materials beyond simple Hookean solids and Newtonian fluids.[66.1] The recognition of materials that did not fit neatly into these categories marked a significant milestone in the evolution of rheology as a distinct scientific discipline by the turn of the 20th century.[66.1]In this section:
Rheological Properties
Viscosity and Its Measurement
Viscosity is a fundamental rheological property that quantifies a material's resistance to flow and deformation under applied stress. It is essential for understanding how materials behave in various applications, particularly in the food industry, where the consistency and flow of products are critical for processing and consumer satisfaction. The measurement of viscosity can be achieved through various methods, including the use of rheometers, which apply stress or strain to a sample and measure the resulting deformation or stress.[83.1] In the context of food rheology, viscosity is influenced by several factors, including the composition of the food matrix and the presence of additives or modifiers that can alter flow behavior. For instance, rheological parameters such as yield stress and plastic viscosity are routinely measured to ensure the quality of food products and to determine optimal processing conditions.[94.1] Yield stress, in particular, is significant as it affects how materials flow in processing equipment, such as during the continuous flow of food through pipes.[91.1] Various techniques are employed to measure the rheological properties of food products. Capillary viscometers, for example, are used to assess the viscosity of food materials like carboxymethyl cellulose solutions and pregelatinized starch.[106.1] Additionally, advanced methods such as Large Amplitude Oscillatory Shear (LAOS) measurements provide insights into the nonlinear rheological behavior of food products, although they require more complex analysis compared to standard oscillatory measurements.[107.1] The selection of appropriate measurement techniques is crucial, as it directly impacts the understanding of a product's texture and flow characteristics, which must align with consumer expectations.[108.1] Overall, the study of viscosity and its measurement is vital for the development and optimization of food products, ensuring they meet both functional and sensory requirements.Non-Newtonian Fluids
Non-Newtonian fluids are characterized by their unique flow behavior, which differs significantly from that of Newtonian fluids. Unlike Newtonian fluids, where the viscosity remains constant regardless of the applied shear rate, non-Newtonian fluids exhibit a viscosity that can change with the shear rate. This behavior is often described through various rheological properties, including thixotropy and viscoelasticity. Thixotropy is a specific property of certain non-Newtonian fluids that allows them to become less viscous when subjected to shear stress. For instance, thixotropic fluids may appear gel-like when at rest but will thin out and flow more easily when stirred or shaken. A classic example of a thixotropic fluid is quicksand, which remains thick and stable until disturbed, at which point it flows more freely.[122.1] This property is crucial in various engineering applications, as it influences how materials behave during processing and application. Viscoelasticity is another important characteristic of non-Newtonian fluids, combining both viscous and elastic properties. Materials that exhibit viscoelastic behavior can deform under stress and return to their original shape when the stress is removed, but the extent of this recovery can depend on the duration and magnitude of the applied stress.[119.1] The interplay of viscosity and elasticity in these materials is essential for understanding their performance in real-world applications, such as in the formulation of food products and cosmetics, where both properties significantly affect texture and stability.[101.1] The behavior of non-Newtonian fluids is influenced by several factors, including temperature, composition, and processing methods. For example, in food materials, the elasticity can be affected by the type and amount of ingredients, such as proteins and fats, which play a critical role in determining the final product's texture and mouthfeel.[103.1] Similarly, in cosmetic formulations, measuring the elasticity of products is vital for ensuring efficacy and safety, guiding formulation decisions, and driving innovation.[101.1]Applications Of Rheology
Industrial Applications
Rheology, the science of flow and deformation of matter, has diverse applications across various industrial sectors, particularly in food processing and mineral industries. In the food industry, rheology is crucial for understanding the deformation and flow of food materials under specific conditions, which aids in optimizing processes and enhancing product quality. Food engineers utilize rheological data to develop relationships between rheology and processing, thereby improving product texture and consumer satisfaction.[133.1] The study of food rheology also helps in addressing textural shortcomings in processed foods, ultimately leading to better consumer acceptability.[132.1] In polymer processing, rheology plays a vital role in the design and optimization of manufacturing techniques. The principles of rheology are applied to understand the behavior of polymeric materials during various processing operations, such as mixing, molding, and advanced techniques like 3D printing.[140.1] Rheological characterization is essential for assessing the processability of polymers, which includes understanding how materials deform and flow under stress.[139.1] This understanding allows manufacturers to optimize processing conditions, troubleshoot issues, and select appropriate materials for specific applications.[140.1] In the mineral processing industry, rheology significantly influences operations such as slurry transportation, ore grinding, and mineral separation. The rheological behavior of mineral slurries can affect inter-particle interactions, which are critical for processes like flotation separation.[144.1] By integrating rheological principles, industries can enhance the efficiency and sustainability of mineral processing operations, leading to improved resource recovery and waste management.[146.1] For instance, effective handling of mineral suspensions at high concentrations can minimize waste production, demonstrating the practical benefits of applying rheological insights in mineral processing.[146.1]Rheology in Food and Pharmaceuticals
Rheology plays a crucial role in the food and pharmaceutical industries by influencing texture perception and product quality. The textural properties of food, such as consistency and flow, are essential for understanding storage stability and consumer acceptance. Food rheology, which examines these properties under specified conditions, is vital for determining how long food can be stored and how stable it will remain.[153.1] Recent advancements in rheological and sensorial analyses have enhanced the understanding of food structural breakdown and bolus development, which are critical for evaluating sensory textures.[154.1] Techniques such as rheometry provide quantitative data on how materials flow, deform, and fracture, thereby linking mechanical properties to sensory attributes.[154.1] The integration of rheology with other technologies, including tribology and multi-modal tactile sensing, is expected to deepen insights into sensory texture perception and improve food texture evaluation methods.[167.1] Consumer acceptance of food is significantly influenced by its texture, which is a dominant factor affecting food choice and palatability.[156.1] Various sensory evaluation methods, such as the time-intensity method (TI) and dynamic quantitative descriptive analysis (D-QDA), are employed to assess texture perception during food oral processing.[167.1] Current rheological techniques have shown effectiveness in evaluating attributes related to mechanical and surface properties, including thickness, astringency, and creaminess.[155.1] Moreover, the microstructural composition of food materials, including factors such as source, morphological properties, and the presence of polymer compounds, significantly affects their rheological characteristics.[168.1] Advanced rheological techniques, complemented by sensory evaluations, enable food scientists to predict and control textures with unprecedented precision, thereby enhancing the overall quality of food products.[166.1] This synergy between rheology and sensory analysis is essential for innovating and optimizing food textures to meet consumer preferences.In this section:
Recent Advancements
Innovations in Rheometric Techniques
Recent advancements in rheometric techniques have significantly enhanced the understanding and application of rheology in various fields, particularly in polymer processing. One notable innovation is the development of high-image-density particle image velocimetry, which allows for the quantitative resolution of instantaneous, two-dimensional sections of complex fluid flows, thereby providing deeper insights into flow behavior.[180.1] Additionally, high-speed microscopic imaging combined with geometric moiré interferometry has been employed to study the dynamic behavior of complex soft materials, enabling in-situ, full-field visualization of micro-scale deformations and forces.[181.1] The integration of machine learning methodologies into rheological studies has also emerged as a transformative approach. These methodologies can be classified into data-centric and physics-informed frameworks, with the latter combining physical laws with data to produce generalizable predictions. This has proven effective in solving rheological differential equations and enhancing constitutive modeling.[179.1] Furthermore, the growth in computational power has facilitated the use of data-driven techniques, allowing for the processing of large datasets that were previously unmanageable, thus revolutionizing the interpretation of flow behavior in complex materials.[178.1] Multiscale modeling techniques represent another significant advancement, bridging the gap between microscopic behaviors and macroscopic flow properties. For instance, a multiscale simulation method has been utilized to calculate the rheological properties of entangled Nylon 6 melts, employing a three-level approach that includes all-atom, coarse-grained, and slip-spring models.[187.1] This method exemplifies how multiscale approaches can enhance the understanding of rheological applications by integrating various levels of resolution.[186.1]In this section:
Tools And Techniques In Rheology
Measurement Techniques
Rheological measurement techniques are pivotal for analyzing the flow and deformation characteristics of materials, which is crucial across various industries. These techniques focus on quantifying parameters such as stress, strain, shear rate, yield value, viscosity, and elasticity, essential for assessing material performance [212.1]. A key instrument in this field is the rheometer, which applies stress or strain to a sample and measures the resulting deformation or stress, thereby connecting a material's intrinsic properties to its overall performance [213.1]. Modern advancements in rheological analysis emphasize real-time measurements and the modeling of viscoelastic behavior in complex materials. These methodologies enhance our understanding of material responses to applied forces, facilitating the exploration of both solid-like and fluid-like behaviors [214.1]. The integration of machine learning into rheological analysis represents a significant innovation, enabling the prediction of behaviors such as thixotropy, viscoelasticity, and viscoplasticity through sophisticated models [225.1]. These models leverage historical data to identify complex patterns in material functions, thereby improving prediction accuracy regarding material performance. In product formulation, particularly within the food and pharmaceutical sectors, controlling rheological properties is vital. Rheology modifiers are instrumental in adjusting the flow and deformation behavior of formulations, influencing characteristics like stability and drug release rates [222.1]. For instance, the rheological properties of drug-polymer mixtures can significantly impact the processability of drug formulations and the final product's physical stability [221.1]. Thus, the application of rheological measurement techniques is crucial for optimizing formulations to meet specific performance criteria across various applications [223.1].Challenges In Rheology
Limitations of Current Methods
The unique properties of hagfish slime present significant challenges in the field of rheology, particularly in the measurement and characterization of its flow behavior. Hagfish slime is composed of mucins and protein threads, forming a dilute, elastic, and cohesive gel that exhibits viscoelastic behavior at low concentrations.[269.1] This viscoelastic nature complicates the application of traditional rheological measurement techniques, as the soft and wet characteristics of such biomaterials often impose substantial difficulties in characterization methods.[259.1] One of the primary challenges arises from the inability of hagfish to control the concentration of the slime they excrete, which is released into a vast volume of water. This results in a gel that is sticky and cohesive, capable of clogging the mouth or gills of predators, thereby facilitating the hagfish's escape.[258.1] The dynamic nature of this gel formation raises questions about the robustness of its rheological properties across varying environmental conditions.[256.1] Moreover, the flow behavior of hagfish slime is influenced by the unidirectional flow experienced during suction feeding by predators, which can be mimicked using extensional rheology. This method reveals that elongational stresses significantly increase mucin viscosity, further complicating the measurement process.[257.1] The narrow concentration range studied (0.01-0.08 wt%) also limits the applicability of findings to real-world scenarios, where the slime is exuded into an "infinite" sea of water.[270.1]Future Directions in Rheological Research
Recent advancements in rheological research are increasingly focused on integrating machine learning methodologies to enhance predictive accuracy and efficiency in modeling material behavior. Physics-informed machine learning (PIML) has emerged as a significant approach, combining physical laws and domain knowledge with data to produce generalizable and physically consistent predictions. This method has proven effective in solving rheological differential equations and utilizing multi-fidelity datasets to improve predictions and constitutive modeling.[268.1] Moreover, the development of customizable data-driven modeling techniques aims to facilitate the rapid computational design of rheologically complex fluids, akin to the advancements seen in other fields through machine learning frameworks.[267.1] The application of PIML is expected to revolutionize the understanding of complex fluid behaviors, particularly under varying shear conditions, by automating the development of digital twins for these materials.[274.1] In addition to machine learning, experimental techniques are also evolving to better characterize the flow behavior of complex materials. High-image-density particle image velocimetry has been identified as an effective method for quantitatively resolving instantaneous, two-dimensional sections of complex fluid flows.[271.1] Furthermore, high-speed microscopic imaging combined with dynamic force measurements allows for in-situ visualization of the dynamic behavior of soft materials, providing deeper insights into their rheological properties.[272.1] As the field progresses, the integration of advanced computational methods and innovative experimental techniques will likely address existing challenges in rheology, paving the way for new applications in various industries, including food and pharmaceuticals.[253.1] The ongoing research in these areas promises to enhance our understanding of shear thickening phenomena and other complex rheological behaviors, ultimately leading to improved material processing and performance.References
[3] Rheology: Current Biology - Cell Press — Rheology is the study of how materials deform in response to forces. Learn the basics of stress, strain, elasticity, viscosity and their applications in cell biology.
[4] Rheology Basics and Testing Rheological Properties - Technology Networks — By examining the relationship between stress and deformation, rheology connects a material’s intrinsic properties to its overall performance.1 A key tool in this field, the rheometer, applies stress or strain to a sample and measures the resulting deformation or stress.2 Rheology explores materials through two main aspects: deformation and flow. Rheology is the scientific study of how materials deform and flow in response to applied forces, encompassing both solid-like and fluid-like behaviors, and linking these responses to the material's properties and performance.4,5 Rheology modifiers are additives or ingredients used to adjust or modulate the flow and deformation behavior of a material, tailoring its viscosity, elasticity or thixotropic properties.
[6] PDF — Rheology is the science that deals with the way materials deform when forces are applied to them. The term is most commonly applied to the study of liquids and liquid-like materials such as paint, catsup, oil well drilling mud, blood, polymer solutions and molten plastics, i.e., materials that flow, although rheology also includes the study of the deformation of solids such as occurs in metal
[7] Application of Rheology - Thermo Fisher Scientific — Pharmaceutical applications of rheology Rheological properties are important to understanding the stability of both liquid and semi-solid pharmaceutical products. For example, a nasal spray needs to demonstrate a certain viscosity so that the active ingredient can be applied via spraying.
[8] PDF — Figure 7 shows the importance of the cooling stage in comparison with the other steps involving the manufacture of a plastic part by injection molding; o Continuous processes like extrusion will require long lines, with lengthy cooling tanks, in order to guarantee sufficiently high throughputs (in other words, lengthier tanks ensure longer times for heat exchanges); o Parts made of plastics are generally thin, as they are economically more interesting to produce than thicker ones (they cool faster); o Plastics processing equipment is generally designed to keep the surface/volume UNESCO – EOLSS SAMPLE CHAPTERS RHEOLOGY- Vol. II - Rheology in Materials Engineering - João Maia, José Covas, Bruno de Cindio, Domenico Gabriele ©Encyclopedia of Life Support Systems (EOLSS) ratios of flow channels as high as possible.
[12] Shear thinning - Wikipedia — Classification of fluids with shear stress as a function of shear rate: Pseudoplastic, Bingham plastic and Bingham pseudoplastic all show reduction in apparent viscosity with increasing shear rate.. In rheology, shear thinning is the non-Newtonian behavior of fluids whose viscosity decreases under shear strain.It is sometimes considered synonymous for pseudo-plastic behaviour, and is
[14] Food Rheology - an overview | ScienceDirect Topics — Food rheology is the study of the consistency and flow of food under specified applied forces, to understand the underlying physicochemical principles of 'structuring' by food materials and their interaction. ... The viscosity decrease in shear-thinning fluids may be attributed to, for example, orientation of rod-shaped particles, fibers
[15] Rheology of liquid foods under shear flow conditions: Recently used ... — Food rheology has been a useful tool over the years to assess the effect of new processes, new product development, formulation changes, ingredient or thickener substitutions, macromolecular interactions, process variables, and the acceptance of products by the consumer. ... 2022) or shear-thinning behavior (Cheng et al., 2023; Outrequin et al
[18] REACTIONS IN A VISCOUS MEDIUM - HASLER Group — REACTIONS IN A VISCOUS MEDIUM Mixing of highly viscous products (several thousand Pa.s) is common in various industries including chemical, pharmaceutical, petrochemical and food. Operators face challenges in preparing complex formulations, requiring effective production solutions amidst managing viscosity effects and multiple process sub-stages.
[19] PDF — Viscosity plays an important role in pharmaceutical development, significantly impacting drug formulation, manufacturing processes, drug delivery systems, and ultimately, therapeutic outcomes. Understanding the influence of viscosity is vital in optimizing pharmaceutical formulations for improved efficacy, stability, and patient compliance.
[21] Viscosity Determination - Improved Pharma — Understanding and controlling the viscosity of your material can be a critical step in its formulation-design space, manufacture, storage, and transportation.
[46] Structural Rheology in the Development and Study of Complex Polymer ... — Objects of the study. 2. Rheological Approaches to the Study of Polymer Materials. A determination of the composition of a polymer material, its structure, and phase state based on its rheological properties in melts and solutions is the reverse task of rheology, created as a new field of physics for colloid chemists on the initiative of Eugene Bingham and Markus Reiner at the end of the 1920s
[47] What is Rheology? - RheoSense — Wherever a material flows, rheology is involved, meaning it affects us nearly everywhere we go. While the term "rheology" was not coined until 1929, Sir Isaac Newton and Robert Hooke are both attributed "in setting the boundaries of the modern science of Rheology" hundreds of years earlier. (History of Rheology - Kenneth Walters
[65] The International Society of Biorheology - University of Oklahoma — Quantitative rheology owes its origin to Robert Hooke who published his law of elasticity "ut tensiosic vis" in anagram form. ... The observation of circulation of blood in capillary vessels of the lung by Marcello Malpighi. 1687 Isaac Newton who, in his "Principia" impicit defined "lack of slipperiness" (viscosity) as the constant ratio of
[66] PDF — He put forward a (linear) equation relating stress σ and strain γ of the form: UNESCO – EOLSS SAMPLE CHAPTERS RHEOLOGY- Vol. I - History of Rheology - Kenneth Walters ©Encyclopedia of Life Support Systems (EOLSS) Figure 2. UNESCO – EOLSS SAMPLE CHAPTERS RHEOLOGY- Vol. I - History of Rheology - Kenneth Walters ©Encyclopedia of Life Support Systems (EOLSS) So, in summary, we can say that, by the turn of the 20th century, there was a general acknowledgement of the existence of materials which could not be classified as Hookean solids or Newtonian fluids. [Contains an important extension to the Bingham model.] UNESCO – EOLSS SAMPLE CHAPTERS RHEOLOGY- Vol. I - History of Rheology - Kenneth Walters ©Encyclopedia of Life Support Systems (EOLSS) Hooke R.
[67] PDF — Newtonian flow or law of Rheology Newton's viscosity law's states that, the shear stress between adjacent fluid layers is proportional to the velocity gradients between the two layers. The ratio of shear stress to shear rate is a constant, for a given temperature and pressure, and is defined as the viscosity or coefficient of viscosity.
[74] The emergence of rheology | Physics Today | AIP Publishing — T HE DEFINITION of the newly coined word "rheology" in the constitution of the Society of Rheology, when it was founded in 1929 under Eugene C. Bingham of Lafayette College, was "fundamental and practical knowledge concerning the deformation or flow of matter." As Markus Reiner recalled telling Bingham at the time, this word would appear to have the same meaning as the term continuum
[75] PDF — He put forward a (linear) equation relating stress σ and strain γ of the form: UNESCO – EOLSS SAMPLE CHAPTERS RHEOLOGY- Vol. I - History of Rheology - Kenneth Walters ©Encyclopedia of Life Support Systems (EOLSS) Figure 2. UNESCO – EOLSS SAMPLE CHAPTERS RHEOLOGY- Vol. I - History of Rheology - Kenneth Walters ©Encyclopedia of Life Support Systems (EOLSS) So, in summary, we can say that, by the turn of the 20th century, there was a general acknowledgement of the existence of materials which could not be classified as Hookean solids or Newtonian fluids. [Contains an important extension to the Bingham model.] UNESCO – EOLSS SAMPLE CHAPTERS RHEOLOGY- Vol. I - History of Rheology - Kenneth Walters ©Encyclopedia of Life Support Systems (EOLSS) Hooke R.
[76] Dispersion and the Principles of Powder Rheology - PowderTechnology info — In the mid-20th century, with the rise of materials science and the development of more sophisticated analytical tools, powder rheology became a distinct field of study. Researchers like Andrew Jenike made substantial contributions to the understanding of powder flow, introducing fundamental concepts like the flow function and cohesive strength.
[83] Rheology Basics and Testing Rheological Properties — By examining the relationship between stress and deformation, rheology connects a material’s intrinsic properties to its overall performance.1 A key tool in this field, the rheometer, applies stress or strain to a sample and measures the resulting deformation or stress.2 Rheology explores materials through two main aspects: deformation and flow. Rheology is the scientific study of how materials deform and flow in response to applied forces, encompassing both solid-like and fluid-like behaviors, and linking these responses to the material's properties and performance.4,5 Rheology modifiers are additives or ingredients used to adjust or modulate the flow and deformation behavior of a material, tailoring its viscosity, elasticity or thixotropic properties.
[91] Applications of Rheological Data Into the Food Industry — The latter example has major implications for designing continuous flow processing plant (eg, a UHT process). If an outer radial section of food material in the cylindrical pipe remains static during flow (as a result of a yield stress), the remaining material will increase in velocity as the cross-sectional area becomes reduced.
[94] DETERMINING THE YIELD STRESS OF FOOD PRODUCTS - ResearchGate — Measurement of yield stress is important in ensuring the quality of various food products, as well as in determining the optimal processing and handling conditions.
[101] Cosmetic Product Development and Testing. Elasticity, Tissue ... - ADSL — Measuring skin elasticity and tissue stiffness using an Elasticity Meter is an important part of the cosmetic product development process. These measurements help ensure product efficacy, substantiate marketing claims, guide formulation decisions, ensure product safety, and drive product innovation.
[103] Viscoelasticity in the Food Industry - Blogger — The vast majority of food materials show a combination of viscous and elastic behaviour although many show much more of one than the other. There are some exceptions - hard crackers are generally completely elastic, whereas oil and runny honey usually show no elastic behaviour.
[106] Rheological Properties of Food - SpringerLink — Furthermore, in the food industry, capillary viscometers can also be used to measure the rheological properties (e.g., power-law parameters, thixotropy) of food materials, including carboxymethyl cellulose solutions, pregelatinized starch, locust bean gum, and enzymes hydrolyzing complex polysaccharides . When a capillary viscometer is used to
[107] Advances in rheological measurements of food products — LAOS measurement could be extended for fundamental rheological measurements of food products in the nonlinear region. Compared to SAOS, the analysis of test results obtained by LAOS is more complex, and can be accomplished by different calculation techniques. ... Tribological method to measure lubricating properties of dairy products. J Food
[108] PDF — other methods try to emulate a certain application by utilizing special rotors and/or measuring fixtures. One such application is studying the texture of food products, which has to match the consumer's expectations. With specially designed probes a rotational rheometer can test various important food properties such as softness, stickiness or
[119] Rheology | Viscosity, Elasticity & Flow in Mechanics — The interplay of viscosity, elasticity, and flow in rheology offers insights into the behavior of materials under various conditions, making it an indispensable field in science and engineering. Advanced Concepts in Rheology Delving deeper into rheology, we encounter advanced concepts like viscoelasticity, thixotropy, and dilatancy.
[122] What is Thixotropy? (with pictures) - AllTheScience — Thixotropy is a property exhibited by some fluids which have a gel-like consistency when they are stationary, but which thin when they are subjected to shear stress. One of the classic examples of a thixotropic fluid is quicksand. As long as it is undisturbed, the sand will be relatively thick.
[132] Why Rheology is Important in Food Technology - AZoM.com — An accurate understanding of food rheology and microstructure reduces textural shortcomings in the processed foods, which in turn enhances consumer satisfaction. Application of Rheology in the Food Industry Several scientists have defined food rheology as studying the deformation and flow of food material under well-defined conditions.
[133] Food Rheology - an overview | ScienceDirect Topics — The application of rheology to study food is primarily for the following three purposes (Fischer and Windhab, 2011). First, food engineers, who try to develop rheology-process relationships of the food, use rheological data for process or product optimization.
[139] Polymer Rheology - an overview | ScienceDirect Topics — Measurement techniques are described as well as factors that influence polymer rheology, including the strain history of the process (strain, rate of strain, and time), the environment (temperature and pressure), and the structure of the polymer.
[140] PDF — Research and Reviews: Journal of Engineering and Technology ISSN: 2319-9873 RRJET| Volume 13 | Issue 1 |March, 2024 12 Understanding Rheological Characterization in Polymer Extrusion for Additive Manufacturing Stacy Leb* Department of Electrical Engineering, Palawan State University, Puerto Princesa, Philippines Opinion Article Received: 26-Feb-2024, Manuscript No. JET-24-132201; Editor assigned: 29-Feb-2024, Pre QC No. JET-24-132201 (PQ); Reviewed: 14-Mar-2024, QC No. JET-24-132201; Revised: 21-Mar-2024, Manuscript No. JET-24-132201 (R); Published: 28-Mar-2024, DOI: 10.4172/ 2319-9873.13.1.006. However, achieving optimal printing quality and mechanical properties in polymer extrusion-based additive manufacturing heavily relies on understanding the rheological behavior of polymers during the extrusion process. By accurately characterizing the viscosity of polymer melts at different temperatures and shear rates, manufacturers can optimize processing conditions to achieve desired flow behavior and printing quality. By understanding the rheological behavior of the polymer melt, engineers can troubleshoot processing issues, optimize material formulations, and design custom extrusion systems tailored for specific additive manufacturing applications.
[144] The importance of rheology in mineral flotation: A review — The rheological behaviour of mineral slurries indicates the level of inter-particle interaction or aggregation, and therefore, it can be used as a useful processing control parameter. The flotation separation of minerals may be influenced by inter-particular interactions, and rheological data can offer a direct approach to further understanding
[146] Rheology and the Minerals Industry: Mineral Processing and Extractive ... — The paper concludes with an example of where rheology and its understanding has been used for effective waste minimisation in the minerals processing industry. Here is it shown how handling mineral suspensions at high concentrations can very effectively reduce or minimise the waste being produced in many mineral processes.
[153] Food rheology - Wikipedia — The textural properties of a peanut butter and jelly sandwich. Food rheology is the study of the rheological properties of food, that is, the consistency and flow of food under tightly specified conditions. The consistency, degree of fluidity, and other mechanical properties are important in understanding how long food can be stored, how stable it will remain, and in determining food texture.
[154] Explaining food texture through rheology - ScienceDirect — Novel rheological and sensorial analyses are working toward a better understanding of food structural breakdown, bolus development, and the associated properties and attributes of the food as it undergoes these changes. Rheometry, which measures how materials flow, deform, and fracture, provides quantitative information on food mechanical properties that can be used to indicate sensory textures and screen samples for trained panel evaluation. Because the way in which a food deforms, fractures, flows, and breaks down is a key component of textural sensations, significant effort has been given to determining relationships between food rheological behaviors and sensory texture attributes. Food structure: roles of mechanical properties and oral processing in determining sensory texture of soft materials Rheology to tribology: applications of tribology in studying food oral processing and texture perception
[155] Methods and instruments for the evaluation of food texture: Advances ... — The review provides a possible direction that integrating the technologies not only by rheology and tribology, but also by multi-modal tactile sensing, will deepen the understanding of sensory texture perception and advance the instrument development for food texture evaluation. In food oral processing, common sensory texture perception evaluation methods include the time-intensity method (TI) (Cliff & Heymann, 1993; Le Quéré & Schoumacker, 2023), dynamic quantitative descriptive analysis (D-QDA) (Delarue & Sieffermann, 2004; Pu et al., 2021), temporal dominance of sensations (TDS) (Mehta et al., 2023; Pineau et al., 2009), and temporal check-all-that-apply (TCATA) (Castura et al., 2016; Castura et al., 2022). Current rheological and tribological methods and instruments have shown good results in evaluating food texture attributes related to mechanical and surface properties, such as thickness, astringency, and creaminess.
[156] Food Texture and Its Perception, Acceptance and Evaluation ... — The acceptance of food by the consumer is dependent on the rheology and texture of food. 15 Food texture is one of the dominant factors which affect the food choice. 14 Food texture is an important factor for food palatability and thus affects food eating behavior. 16 Food texture is defined as the combined sensation derived from various
[166] Advanced Rheology for Texture Design - foodinfotech.com — Advanced rheological techniques need to be complemented with sensory evaluation to ensure the desired texture is achieved. Conclusion. Advanced rheology is a powerful tool in the quest for perfect food texture. It enables food scientists to predict, control, and innovate textures with a level of precision that was once unimaginable.
[167] Methods and instruments for the evaluation of food texture: Advances ... — The review provides a possible direction that integrating the technologies not only by rheology and tribology, but also by multi-modal tactile sensing, will deepen the understanding of sensory texture perception and advance the instrument development for food texture evaluation. In food oral processing, common sensory texture perception evaluation methods include the time-intensity method (TI) (Cliff & Heymann, 1993; Le Quéré & Schoumacker, 2023), dynamic quantitative descriptive analysis (D-QDA) (Delarue & Sieffermann, 2004; Pu et al., 2021), temporal dominance of sensations (TDS) (Mehta et al., 2023; Pineau et al., 2009), and temporal check-all-that-apply (TCATA) (Castura et al., 2016; Castura et al., 2022). Current rheological and tribological methods and instruments have shown good results in evaluating food texture attributes related to mechanical and surface properties, such as thickness, astringency, and creaminess.
[168] Rheological analysis of food materials - ScienceDirect — The rheological characteristics of any product depend on the source, morphological property, concentration, presence of different polymer compounds, pasting conditions, and storage conditions. For example, the rheological properties of liquid food materials are influenced by the dispersion phase (Ahmed et al., 2016). A dispersion is signified
[178] Data-driven methods in Rheology | Rheologica Acta - Springer — With a consistent growth in computational power, even today's personal computers enable storage and process of large amounts of data far beyond what was possible a decade ago. With these technological advances, over the past few years, data-driven techniques have presented themselves as transformative platforms across virtually all science and engineering disciplines. Rheology and non
[179] Data-driven techniques in rheology: Developments, challenges and ... — We classify different machine learning (ML) methodologies into data-centric and physics-informed frameworks. Physics-informed machine learning combines physical laws and domain knowledge with data to produce generalizable and physically consistent predictions, proving effective in solving rheological differential equations, utilizing multi-fidelity datasets to enhance predictions, and constitutive modeling. Table 1 provides a short overview of various ML techniques in the field of rheology and complex fluids, addressing applications from both data-centric and physics-informed perspectives. Following this, Section Data-centric approaches summarizes some successful ML implementations in rheological properties predictions, high-throughput material characterization, properties optimization, fluid flow modeling, and acceleration of numerical simulations from a data-centric view point. Review of modeling schemes and machine learning algorithms for fluid rheological behavior analysis
[180] Advanced experimental techniques and complex flow behavior - ResearchGate — The experimental technique of high-image-density particle image velocimetry makes it possible to resolve quantitatively instantaneous, two-dimensional sections of complex fluid flows.
[181] An Experimental Technique for the Dynamic Characterization of Soft ... — We describe an experimental technique to study the dynamic behavior of complex soft materials, based on high-speed microscopic imaging and direct measurements of dynamic forces and deformations. The setup includes high sensitivity dynamic displacement measurements based on geometric moiré interferometry and high-speed imaging for in-situ, full-field visualization of the complex micro-scale
[186] Application of a multiscale approach for modeling the rheology of ... — Multiscale approaches have been proposed to couple rheological information from DPD with computational fluid dynamics (CFD) simulations. The CFD technique reproduces the macroscale piece of equipment, implementing a rheology model built using the Gaussian process regression, a mathematical tool related to machine learning.
[187] PDF — Abstract A multiscale simulation method is used to calculate the rheological properties of entangled Nylon 6 melts, including the stress relaxation modulus, storage and loss moduli, and the melt viscosity. The three-level multiscale approach includes all-atom, coarse-grained and slip-spring models, each operating at dif-ferent levels of resolution and encompassing a wide range of length scales
[212] Rheological Techniques - SpringerLink — The main objectives of this entry are to describe the various rheological techniques that can be applied to obtain the various rheological parameters such as stress, strain, shear rate, yield value, viscosity, and elasticity. These various parameters have been defined in the entry on rheology to which the reader should refer to for any detail.
[213] Rheology Basics and Testing Rheological Properties - Technology Networks — By examining the relationship between stress and deformation, rheology connects a material’s intrinsic properties to its overall performance.1 A key tool in this field, the rheometer, applies stress or strain to a sample and measures the resulting deformation or stress.2 Rheology explores materials through two main aspects: deformation and flow. Rheology is the scientific study of how materials deform and flow in response to applied forces, encompassing both solid-like and fluid-like behaviors, and linking these responses to the material's properties and performance.4,5 Rheology modifiers are additives or ingredients used to adjust or modulate the flow and deformation behavior of a material, tailoring its viscosity, elasticity or thixotropic properties.
[214] Rheological Measurement Techniques and Analysis Methods — Rheological Measurement Techniques and Analysis Methods provides a comprehensive exploration of modern rheological analysis, offering key insights into the flow and deformation behaviors of complex materials across various industries. This edited volume brings together advanced techniques and methodologies, with a particular focus on real-time measurements, modeling of viscoelastic
[221] Role of rheology in formulation and process design of hot melt extruded ... — The rheological properties of drug-polymer mixtures can significantly influence the processability of drug formulations via HME and eventually the end-use product properties such as physical stability and drug release. The objective of this review is to provide an overview of various rheological techniques and properties that can be used to
[222] Rheological investigation of cosmetics and pharmaceuticals — The rheological characteristics of cosmetics and pharmaceuticals are important for production, packaging, filling, and storage. Customers appreciate the sensation of a skin cream when applied; they want the toothpaste to remain on the brush after squeezing it out of the tube, and they want medicine in the optimal condition to take effect wherever it should.
[223] PDF — such as new ingredient selections, formulation preparations, material packaging, and shelf storage are associated with a complex flow of materials. The appli-cation and acceptance of pharmaceuticals and cosmetics are also dependent on the flow properties of the final product. Therefore, rheological measurements, an im-
[225] One test to predict them all: Rheological characterization of complex ... — The calibrated neural network is subsequently used to predict various rheological behaviors: (i) thixotropy, assessed via hysteresis loop tests (Section 3.2), (ii) viscoelasticity, analyzed through oscillatory stress response and dynamic moduli in strain sweep tests (Section 3.3), and (iii) viscoplastic behavior, evaluated using steady shear viscosity and creep tests to measure yield stress and yielding dynamics (Section 3.4). By training the network to stress response in a simple rate controlled test (MITT) the NARX model identifies intricate patterns in material functions and their dependence on the shear history, as the model considers the shear stress response in the past two time steps for prediction.
[253] Discontinuous shear thickening in dense suspensions: Mechanisms, force ... — Dense suspensions of particles in a liquid, with industrial examples including coatings or precursors to solid ceramics and cements, can be quite difficult to process because their flow properties are very sensitive to particle surface interactions. We focus on the extreme rate dependence known as "discontinuous shear thickening" (DST) where the viscosity undergoes a finite and typically
[256] Concentration-independent mechanics and structure of hagfish slime — The defense mechanism of hagfish slime is remarkable considering that hagfish cannot control the concentration of the resulting gel directly; they simply exude a concentrated material into a comparably "infinite" sea of water to form a dilute, sticky, cohesive elastic gel. This raises questions about the robustness of gel formation and rheological properties across a range of
[257] (PDF) Hagfish slime and mucin flow properties and their implications ... — The unidirectional flow, experienced by hagfish slime during suction feeding by predators, was mimicked with extensional rheology. Elongational stresses were found to increase mucin viscosity.
[258] View Paper - The Society of Rheology Meeting Web App — When attacked by predators, hagfish excrete a concentrated mucin - protein fiber solution, which forms within milliseconds a large body of slime. Although the slime consists out of vast amounts of water, the diluted mucin and fibers span a cohesive network eventually clogging mouth or gills of the predators and enabling the hagfish to escape.
[259] Non-linear viscoelasticity of hagfish slime | Request PDF — The soft and wet character of biomaterials such as hagfish slime, in particular, often imposes substantial challenges to characterization methods applied in materials science (Ewoldt et al., 2014).
[267] Scientific machine learning for modeling and simulating complex ... - PNAS — We hope that the presentation of such a customizable yet robust method for data-driven modeling of soft materials does for rheology what previous machine learning frameworks have done for so many other fields, allowing the automated development of digital twins for rheologically complex fluids that facilitate rapid computational design and
[268] Data-driven techniques in rheology: Developments, challenges and ... — We classify different machine learning (ML) methodologies into data-centric and physics-informed frameworks. Physics-informed machine learning combines physical laws and domain knowledge with data to produce generalizable and physically consistent predictions, proving effective in solving rheological differential equations, utilizing multi-fidelity datasets to enhance predictions, and constitutive modeling. Table 1 provides a short overview of various ML techniques in the field of rheology and complex fluids, addressing applications from both data-centric and physics-informed perspectives. Following this, Section Data-centric approaches summarizes some successful ML implementations in rheological properties predictions, high-throughput material characterization, properties optimization, fluid flow modeling, and acceleration of numerical simulations from a data-centric view point. Review of modeling schemes and machine learning algorithms for fluid rheological behavior analysis
[269] Hagfish slime and mucin flow properties and their implications for ... — Abstract. When hagfish (Myxinidae) are attacked by predators, they form a dilute, elastic, and cohesive defensive slime made of mucins and protein threads.In this study we propose a link between flow behavior and defense mechanism of hagfish slime. Oscillatory rheological measurements reveal that hagfish slime forms viscoelastic networks at low concentrations.
[270] Concentration-independent mechanics and structure of hagfish slime — Recent work , , on the mechanics of hagfish slime suggests that this material has predominantly elastic properties with a very low elastic modulus(∼ 0.01 Pa). A very narrow range (0.01-0.08 wt%) of concentration was considered in these studies. However, hagfish exudate is ejected into a comparably infinite sea of water and the animal itself cannot directly control the
[271] Advanced experimental techniques and complex flow behavior - ResearchGate — The experimental technique of high-image-density particle image velocimetry makes it possible to resolve quantitatively instantaneous, two-dimensional sections of complex fluid flows.
[272] An Experimental Technique for the Dynamic Characterization of Soft ... — We describe an experimental technique to study the dynamic behavior of complex soft materials, based on high-speed microscopic imaging and direct measurements of dynamic forces and deformations. The setup includes high sensitivity dynamic displacement measurements based on geometric moiré interferometry and high-speed imaging for in-situ, full-field visualization of the complex micro-scale
[274] Machine Learning Model for Monitoring Rheological Properties of ... — The current study introduces a machine learning application toward predicting the rheology of synthetic oil-based mud (flat rheology type) for the full automation system of monitoring the mud rheological properties.