The rheological measurements included both rotational and oscillatory measurements in different conditions, where several chemical and physical properties were measured with Anton Paar MCR302 dynamic rotational rheometer. Studied polysaccharide gels can be clearly defined to be shear thinning and thixotropic materials. They have strong gel forming properties even at low concentrations, which explains the superior thickening behavior for some of the samples. Along with rheological characterization of selected materials the factors behind different phenomena were investigated. To reveal value and potential use of polysaccharide gels the influence of various factors such as concentration, temperature and ionic strength were determined. The measurements showed a clear difference between studied materials under investigated external parameters ...
Different shear rates/shear stresses showed a significant influence on the rheological behavior and thus the viscosity of the alloy. This was true for the liquid material as well as the liquid-solid phase between liquidus and solidus temperatures, which is crucial for the casting processes. The viscosity at high applied shear stresses (like those used in thixo- and rheocasting processes) is significantly lower than when measured at rest. Structural changes on metallographic microsection were observed linking the loss of dendritic structure with the rheological data. Thus high temperature rheology is shown to be a powerful tool to investigate metal alloys in modern casting processes. Introduction Unlike in normal casting processes, thixo- and rheocasting processes employ liquid-solid mixtures (called semisolids within metallurgy) containing non-dendritic solid fractions that are pressed into dies. One of the main advantages of liquid-solid material (semi-solids) castings as opposed to ...
TY - JOUR. T1 - Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry. T2 - Transition from a laminar regime. AU - Yagi, Takanobu. AU - Sato, Ayaka. AU - Shinke, Manabu. AU - Takahashi, Sara. AU - Tobe, Yasutaka. AU - Takao, Hiroyuki. AU - Murayama, Yuichi. AU - Umezu, Mitsuo. PY - 2013/4/5. Y1 - 2013/4/5. N2 - This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner. The mid-systolic and late-diastolic flows with a Reynolds number of 450 and 230 were ...
The rheology of crude oil mixtures at equilibrium with carbon dioxide (CO2) was studied at elevated pressures and temperatures, similar to those found for oil reservoir conditions. The focus of the work presented in this thesis concerns the measurement of the rheological properties of CO2 saturated mixtures of crude oil. The rheology measurements were made using a high-pressure rheometer coupled to a fluid flow system designed and built in this project. The flow system comprised a mixing vessel and fluid flow loop that allowed the test fluid to be brought into equilibrium with CO2 by stirring and circulating through the rheometer measurement geometry under the pressure and temperature required. Measurements were made for three different fluids saturated with CO2: a light crude oil from the Gulf of Mexico (GoM), Zuata heavy crude oil, and an emulsion of Zuata crude oil with deionized water. The rheological measurements for the GoM crude oil were performed at temperatures of 23 °C and 50 °C and ...
Faculty Mechanical Maritime and Materials Engineering. Date 2008-04-21. Abstract The development, the regulation, and the pathology of the circulatory system (e.g. cardiogenesis, thermoregulation, atherosclerosis) are determined by blood flow induced mechanical forces. While this proposition has been confirmed during recent years, the exact mechanisms still remain unclear. This is mainly due to the fact that those forces could hardly be measured. The goal of the research described in this thesis is the development of a measurement technique that can provide such data for living organisms. Fluid mechanical forces can be deduced from spatial velocity information, as provided by particle image velocimetry. Small, artificial, fluorescent particles with a hydrophilic coating are used to determine the fluid velocity. Fluorescence enables the interference-free recording of the particle motion, and the coating makes the particles invisible to the biological system. Three dimensional flow is accessed ...
This webinar will be held by Tobias Nill, MSc, and Dr. Jan Lauko. Special applications demand special and customized solutions when it comes to the combination of a rheometer with a confocal microscope. Anton Paar rheometers offer unique specifications and provide solutions for maximum working space and flexibility which enables the combination with different confocal microscopes. Confocal Rheo-imaging is a powerful tool for the detailed characterization of the microstructure of complex fluids and soft materials like biomimetic hydroels or colloidal suspensions. Controlled shear conditions and direct linking to the rheological behavior enables deeper understanding of intrinsically complex materials. In this webinar, we show technical challenges and solutions for rheo-confocal combinations and examples for practical applications. Presenters: Tobias Nill is the International Product Manager for the MCR Rheometer Series and is located at Anton Paar in Germany. He has more than 7 years of rheology ...
Get this from a library! White cell rheology and inflammation : proceedings of the 4th Bodensee Symposium on Microcirculation, Constance/Bodensee, June 29th-July 1st, 1984. [K Messmer; Frithjof Hammersen;]
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Get this from a library! Rheology of fresh cement and concrete : proceedings of the international conference organized by the British Society of Rheology, University of Liverpool, UK, March 26-29, 1990. [P F G Banfill; British Society of Rheology.;]
A parallelogram channel has drawn very little or no attention in the open literature although it appears as a cross-sectional configuration of some gas turbine rotor blades. Particle image velocimetry (PIV) is presented of local flow structure in a two-pass 90 deg ribbed-wall parallelogram channel with a 180 deg sharp turn. The channel has a cross-sectional equal length, 45.5 mm, of adjacent sides and two pairs of opposite angles are 45 deg and 135 deg. The rib height to channel height ratio is 0.1. All the measurements were performed at a fixed Reynolds number, characterized by channel hydraulic diameter of 32.17 mm and cross-sectional bulk mean velocity, of 10,000 and a null rotating number. Results are discussed in terms of the distributions of streamwise and secondary-flow mean velocity vector, turbulent intensity, Reynolds stress, and turbulent kinetic energy of the cooling air. It is found that the flow is not periodically fully developed in pitchwise direction through the inline 90 deg ...
Various polymer modified bitumens (PmBs) were prepared and characterized using a dynamic shear rheometer and a bending beam rheometer. PmBs differ considerably in viscoelastic properties depending on base bitumen, and polymer type and content. The rheology of PmBs is strongly related to the morphology, and is also affected by sample preparation.
This review encompases fundamental principles and rheological equations of state, polymer melt rheology (shear and extensional flow, viscoelasticity, die swell and melt fracture) and rheological measurement techniques. It describes the main plastics processing techniques and explains influence of polymer melt rheology upon their operation. 48 figures and more than 80 equations enhance the review, which is also supported by extensive, indexed bibliography.
Particle image velocimetry (PIV) has proven to be a very useful technique in mapping animal-generated flows or flow patterns relevant to biota. Here, theoretical background is provided and experimenta
were the still and moving wave gauge data. First, the wave gauge remained stationary over the horizontal bottom of the flume and recorded water surface elevations with time. Data were collected for two minutes at a frequency of 60 Hz to analyze wave height and period. Secondly, the carriage which supported the wave gauge was slowly moved down the length of the deep water section of the tank. Moving the wave gauge slowly as the waves propagated past allowed for detection of reflected waves in the tank as described by Dean and Dalrymple (1991). The wave gauge was first slowly moved opposite the direction of wave propagation, and then back in the direction of wave propagation. Again, the data was collected for a length of two minutes at a frequency of 60 Hz. The third set of data collected by the wave gauge was not common to all runs. By slowly moving the wave gauge through the surf zone portion of the tank, the wave set-up could be determined. It was hoped to corroborate the wave set-up measured ...
Reactive blends of polypropylene and unsaturated polyester with different compositions were prepared by melt processing using dicumyl peroxide (DCP) as initiator in a plasticoder. Rheological Characteristics of the blends were studied as a function of unsaturated polyester concentration over a range of strain rate. The possibility of forming a graft polymer increased with increasing the unsaturated polyester content. Change in viscosity behavior of the blends was a result of the competing reactions of degradation and grafting.
Rheology is the analytical method of choice to correlate the absolute flow and deformation characteristics of a given product with its behavior towards a certain processing or application step. However, rheology as an integral method only yields answers on the bulk of the investigated sample. It does not give any insights into what is actually happening on the molecular level during a certain processing step.. Raman spectroscopy has shown its ability as a powerful, effective and non-invasive method for chemical analysis. Coupling a rheometer with a Raman spectrometer provides direct information about the molecular structure and the mechanical properties. This is extremely useful for studying the crystallization behavior of polymer melts during processing. It can also provide insight for in-situ characterization and monitoring which can be challenging when working with on-line techniques as only relative flow fields are characterized.. Melting and crystallization are two common phase transitions ...
During the past decade, geoscientists have come to appreciate the often-dominant role played by complex and nonlinear rheologies in the deformation of geologic materials. This is nowhere more evident than in the earths crust and mantle where effective viscosities can vary over many orders of magnitude and different modes of deformation occur. On the largest scale, plate tectonics occurs because of the poorly understood multi-rheological behavior of crustal and mantle rocks. On a smaller scale, complex geomorphic features, such as those in evidence in the Sierra Nevada, are the outcome of flows which are dramatically influenced by variable viscosity, phase transitions, and other physical and chemical properties. Nonlinear rheology, through a number of microscopic processes and macroscopic interactions such as thermal feedback, results in a rich variety of flow behavior including strain localization and instability leading to faulting. Such behaviors are ultimately responsible for such diverse ...
Rapra presented the third successful European conference concentrating on polymer rheology as a practical tool for process control and quality analysis. Papers were presented covering the latest techniques, equipment and innovations in the monitoring and characterisation of polymers. Subjects addressed included the application of rheology to real time processes, quality control and flow behaviour.
5. References. 1 Yildirim, Y. (2005). Polymer modified asphalt binders. Construction & Building Materials, 21(1), 66-72. http://dx.doi.org/10.1016/j.conbuildmat.2005.07.007. [ Links ] 2 Bernucci, L. B., Ceratti, J. A. P., Soares, J. B., & Motta, L. M. G. (2008). Pavimentação Asfáltica: formação básica para engenheiros. Rio de Janeiro: Abeda. [ Links ] 3 Polacco, G., Stastna, J., Biondi, D., Antonelli, F., Vlachovicova, Z., & Zanzotto, L. (2004). Rheology of asphalts modified with glycidylmethacrylate functionalizes polymers. Journal of Colloid and Interface Science, 280(2), 366-373. PMid:15533409. http://dx.doi.org/10.1016/j.jcis.2004.08.043. [ Links ] 4 Topal, A. (2009). Evaluation of the properties and microstructure of plastomeric polymer modified bitumen. Fuel Processing Technology, 91(1), 45-51. http://dx.doi.org/10.1016/j.fuproc.2009.08.007. [ Links ] 5 Domingos, M. D. I., & Faxina, A. L. (2015). Rheological analysis of asphalt binders modified with Elvaloy® terpolymer and ...
Grouting is used in underground construction to reduce the water flow into tunnels and caverns and to limit the lowering of the surrounding groundwater table. Due to their wide availability and low cost relative to other materials, cement based materials are commonly used as grouts and, in this context, the rheology of the cement grout is an important factor. Rheological properties of cement grout such as viscosity and yield stress are commonly measured off-line using laboratory instruments, and some simple tools are available to make field measurements. However, these methods often lack accuracy and reliability. Although the rheological properties of the grout used play a fundamental role in design and execution, no method has yet been developed to measure these properties in-line in field work.. In this work, for the first time, an in-line rheometry method combining the Ultrasound Velocity Profiling (UVP) technique with Pressure Difference (PD) measurements, known as UVP+PD, was successfully ...
2013 - English Non - negligible portion of pol ymer commodity suffers from ageing that participates in sometimes significant changes of products attributes. Rheology represents a useful tool for a description of this process. The aim of this contribution is to evaluate possible ageing of PEO solution ( polyethylen e oxide ( M w =300,000 g/mol) dissolved in water at 10 wt.% concentration) based both on rheological characterization and on quality of electrospun fibres. Rheological measurements in steady shear and oscillatory modes were carried out using a rota tional rheometer MCR 501 (Anton Paar, Austria) equipped with the concentric cylinders geometry. The electrospinning measurements were executed with the help of a proposed laboratory device. The tip - to - collector distance attained 20 cm, applied voltage rang ed from 20 to 30 kV. The obtained electrospun fibres were analysed using a scanning electron microscope (VEGA 3, Tescan, Czech Republic). Both types of measurements were carried out in ...
White Blood Cells: Morphology and Rheology as Related to Function by U Bagge (Editor) starting at $5.50. White Blood Cells: Morphology and Rheology as Related to Function has 2 available editions to buy at Alibris
Whereas mixtures of colloids and non-adsorbing polymers have been studied in great detail in the last two decades, binary colloidal mixtures have not received much attention. Yet, fragmental evidence from asymmetric mixtures of hard spheres indicates a wide-ranging, complex behavior from liquid to crystal to single glass and to double glass, and respective rich rheology. Recently, we addressed the question of softness by investigating a mixture of soft and virtually hard colloidal spheres. We found an unprecedented wealth of states including repulsive single glass (RG), liquid, arrested phase separation (APS) and double glass (DG). This is a consequence of the coupling of softness and osmotic forces due to the hard component. We now report on the rheology of the different states with emphasis on the nonlinear response during start-up of stress at constant rate, its relaxation upon flow cessation, and large amplitude oscillatory shearing. Distinct features are identified, whereas comparison with ...
A process for making particles is provided. In embodiments, a suitable process includes adding a rheology modifier to an emulsion utilized to form toner particles. The rheology modifier permits the use of a higher solid content in the emulsion, with a resulting higher yield of toner particles, without requiring the use of powerful mixing equipment.
books.google.comhttps://books.google.com/books/about/Polymers_as_rheology_modifiers.html?id=3aRRAAAAMAAJ&utm_source=gb-gplus-sharePolymers as rheology modifiers ...
The industry study on global Capillary Rheometer market provides comprehensive review of ongoing market trends, drivers, opportunities, challenges and issues, latest news and events including Capillary Rheometer strategic corporate developments and Capillary Rheometer product innovations. Overall assessments of the global Capillary Rheometer market share from different countries and regions is covered in the report. The competitive landscaping mapping of the current trends are also included in Capillary Rheometer report.. Global Capillary Rheometer Market analyzed the Industry region, including the product price, profit, capacity, production, capacity utilization, supply, demand and Capillary Rheometer industry growth rate etc. Furthermore, Capillary Rheometer report features tables and figures that render a clear perspective of the Capillary Rheometer industry. In the end, the Capillary Rheometer market report introduced investment feasibility analysis, and investment return analysis to ...
Abstract Carnoys solution has been widely undertaken as adjunctive therapy for benign odontogenic tumors. Although its outcomes were highly investigated, little information is available regarding its mechanism of action and the role of chloroform in composition. The aim of this study was to characterize Carnoys solution with and without...
In consideration of the insolubility in water, sensitivity to heat and wide application in the oil and gas industry as a degradable additive, this paper introduces polylactic acid (PLA) to a self-degradable temporary sealing material (SDTSM) to investigate its effect on the SDTSM performance and evaluate its potential to improve the rheological properties and further promote the self-degradation of the material. The thermal degradation of PLA, the rheological properties, compressive strength, hydrated products and water absorption of SDTSMs with different PLA dosages were tested. The analysis showed that the addition of 2% PLA increased the fluidity by 13.18% and reduced the plastic viscosity by 38.04%, when compared to those of the SDTSM without PLA. PLA increased the water absorption of 200 °C-heated SDTSM and had small effect on the types but decreased the hydrate products of 85 °C-cured SDTSM, and created plenty of pores in 200 °C-heated SDTSM. PLA enhanced the self-degradation level of SDTSM by
Twenty out-patients with steady-state diabetes mellitus were given placebo for 12 weeks followed by Ticlopidine for 12 weeks while studied serially for changes in platelet function and blood rheology. Ticlopidine rendered diabetic platelets refractor
The rheological properties of three different microstructures of hydrophobically modified alkalisoluble polymers (telechelic, multisticker and combined) in the presence of various concentrations of anionic surfactant and salt (NaCl) were investigated. Associative polymers containing both ionic sites and small number of hydrophobic groups were obtained, and their thickening properties in aqueous solutions, were investigated. Solution polymerization was used for obtaining the different polymers. Relationships between hydrophobe, sodium dodecyl sulfate (SDS) and NaCl concentration are proposed. Owing to the competition between attractive hydrophobic interaction and repulsive electrostatic interactions, such hydrophobically modified polymers exhibit various rheological behaviors in aqueous solutions, depending on microstructure of polyelectrolyte, SDS and NaCl concentrations.
United States Patent C) US. Cl. 252-33 16 Claims ABSTRACT OF THE DISCLOSURE Compositions characterized by improved rheological properties comprising a material capable of possessing thixotropic or pseudoplastic properties and non-Newtonian colloidal disperse systems. These systems are characterized as colloidal dispersions of solid, metal-containing colloidal particles predispersed in an inert organic liquid and, as an essential third component of the system, an organic compound with molecules which contain a hydrophobic portion and at least onepolar substituent. A typical composition contains polyvinylchloride polymer, a plasticizer for the polymer, and a disperse system comprising calcium carbonate particles, a liquid hydrocarbon dispersing medium, and a calcium petrosulfonate. A method for imparting improved rheological properties to materials susceptible to possessing such properties by incorporating therein these disperse systems is described as are novel non-Newtonian disperse systems per ...
Microrheology is the study of the flow and deformation of fluids on the micrometre scale. It has many benefits over the use of traditional rheomoeters to measure the mechanical properties of fluids. Microrheology has small sample sizes, can extract information about the underlying heterogeneities, often has a lower setup cost, can measure to higher frequencies and can measure the viscoelasticity of in-vivo samples. Work has been carried out to setup and calibrate four different microrheology techniques, namely: diffusing wave spectroscopy, dynamic light scattering, multiple particle tracking and probe laser tracking with a quadrant photodiode and optical traps. This resulted in the ability to measure the viscoelastic properties of a material over approximately eight orders of magnitude, with nanometre resolution on the most sensitive technique; diffusing wave spectroscopy. The link between free Brownian motion and a particle diffusing in a harmonic potential was used to calibrate the trap ...
Peripheral Arterial Occlusive Disease (PAOD) is an acquired inflammatory disease where a peripheral artery becomes occluded due to the buildup of atherosclerotic plaques. In patients that possess collateral arteries, an occlusion can lead to shear induced outward remodeling, arteriogenesis, of these collaterals, partially restoring blood flow. However, newly remodeled collaterals exhibit reduced functional vasodilation, which may impair normal activity, such as ambulation. To model chronic ischemia and arteriogenesis in collaterals, a femoral artery ligation in a murine hindlimb is commonly performed. Previous efforts by our group involved measurements of collateral artery diameter to assess the impact of arteriogenesis on functional vasodilation/vascular reactivity; however diameter measurements are not as descriptive as an assessment of flow, and performing particle image velocimetry allows the change in blood flow control to be investigated. Particle image velocimetry was performed in the profunda
Authors: Baskurt, Oguz K. Article Type: Review Article Abstract: It is has been known for more than 80 years that compared to in vitro determinations, blood behaves as a less viscous fluid under in vivo flow conditions. The experiments of Whittaker and Winton were among the first dealing with the in vivo effects of altered blood rheology, and experimental studies during the second half of 20th century have provided additional evidence for the complexity of in vivo hemodynamics-hemorheology relationships. Careful studies indicate that the impact of a given blood rheology alteration is determined by the properties of the experimental model (e.g., organ or tissue under investigation), experimental approach (e.g., …intravital microscopy, whole organ perfusion) and method used to modify blood rheology. In addition, vascular control mechanisms may play a major role in the resulting hemodynamic effects of a hemorheological alteration: (1) a response simply related to metabolic autoregulation in which ...
In this work, three linear isotactic polypropylenes with different weight-average molecular weights, M-w, and comparable polydispersities were used to produce nonwovens by melt blowing technology at two different temperatures, T. The air/polymer flow rate was changed to maintain the same average fiber diameter, resulting in a different broadness of fiber diameter distribution, which was quantified by the coefficient of variation, CV. The elasticity of the material was evaluated by the reptation-mode relaxation time, lambda(1), and the Rouse-mode reorientation time, lambda(2), determined from the deformation rate dependent shear viscosity data. Extensional rheology was evaluated using uniaxial extensional viscosity measured over a very wide range of strain rates (2 x 10(4) s(-1)-2 x 10(6) s(-1)) using entrance pressure drop and Gibson methods. An obtained plateau value of uniaxial extensional viscosity at the highest extensional strain rates, eta(E,infinity) (normalized by the three times ...
Animal movements result from a complex balance of many different forces. Muscles produce force to move the body; the body has inertial, elastic, and damping properties that may aid or oppose the muscle force; and the environment produces reaction forces back on the body. The actual motion is an emergent property of these interactions. To examine the roles of body stiffness, muscle activation, and fluid environment for swimming animals, a computational model of a lamprey was developed. The model uses an immersed boundary framework that fully couples the Navier-Stokes equations of fluid dynamics with an actuated, elastic body model. This is the first model at a Reynolds number appropriate for a swimming fish that captures the complete fluid-structure interaction, in which the body deforms according to both internal muscular forces and external fluid forces. Results indicate that identical muscle activation patterns can produce different kinematics depending on body stiffness, and the optimal value ...
博士論文. Recently, quantitative flow visualization has become an important tool to investigate three-dimensional complex flow structures in microfluidic. The development of laser, computer and digital image processing techniques made it possible to extract velocity field information from visualized flow images of tracer particles. Particle image velocimetry (PIV) / particle tracking velocimetry (PTV) method has become one of the most useful flow diagnostic technologies in the modern history of fluid mechanics. The particle based velocimetry techniques measure the whole velocity field information in a plane by dividing that is placements Δx and Δy of tracer particles with the time interval Δt during which the particles were displaced. Since the flow velocity is inferred from the particle displacement, it is also important to select proper tracer particles that follow the flow motion accurately without changing the flow properties. These methods have been accepted as a reliable and ...
Double optical tweezers combined with active rheology approach are suggested for dynamic monitoring of the red blood cell elastic properties. Frequency dependence of the phase difference in the forced movement of the erythrocyte opposite edges appeared to be highly dependent on the rigidity of the cellular membrane. Cell relaxation time value is suggested as an effective parameter determining the state of the cell. Photo-induced effects caused by optical trapping are analyzed ...
Magnetorheological Fluid The other fluid that can reinforce Kevlar armor is magnetorheological (MR) fluid. MR fluids are oils that are filled with iron particles. Often, surfactants surround the particles to protect them and help keep them suspended within the fluid. Typically, the iron particles comprise between 20 and 40 percent of the fluids volume. The particles are tiny, measuring between 3 and 10 microns. However, they have a powerful effect on the fluids consistency. When exposed to a magnetic field, the particles line up, thickening the fluid dramatically. The term magnetorheological comes from this effect. Rheology is a branch of mechanics that focuses on the relationship between force and the way a material changes shape. The force of magnetism can change both the shape and the viscosity of MR fluids. The hardening process takes around twenty thousandths of a second. The effect can vary dramatically depending on the composition of the fluid and the size, shape and strength of the ...
Bubbles are ubiquitous in magma during eruption and influence the rheology of the suspension. Despite this, bubble-suspension rheology is routinely ignored in conduit-flow and eruption models, potentially impairing accuracy and resulting in the loss of important phenomenological richness. The omission is due, in part, to a historical confusion in the literature concerning the effect of bubbles on the rheology of a liquid. This confusion has now been largely resolved and recently published studies have identified two viscous regimes: in regime 1, the viscosity of the two-phase (magma-gas) suspension increases as gas volume fraction phi increases; in regime 2, the viscosity of the suspension decreases as phi increases. The viscous regime for a deforming bubble suspension can be determined by calculating two dimensionless numbers, the capillary number Ca and the dynamic capillary number Cd. We provide a didactic explanation of how to include the effect of bubble-suspension rheology in continuum, ...
The Universal Selection Source for Polymer Additives Access Technical info on additives for polymers and the knowledge to select them. shiva performance materials additives rheology viscosity modifiers pa nylon pa nylon
Rheology concerns itself with materials that have aspects of both solids and liquids, and researches the flow and deformation of matter. Malvern Instr
Buy Polymer Rheology: Theory and Practice by Yuri G. Yanovsky from Waterstones today! Click and Collect from your local Waterstones or get FREE UK delivery on orders over £20.
Instron manufactures tensile, compression, fatigue, impact, rheology, and structural testing machines, testing a variety of materials and range of applications. Telephone: +1 800 877 6674
Instron manufactures tensile, compression, fatigue, impact, rheology, and structural testing machines, testing a variety of materials and range of applications. Telephone: +1 800 877 6674
The present invention relates to new associative rheology modifiers, their manufacture and their application in personal care compositions.
Polysaccharides from okra pods (Abelmoschus esculentus) were extracted using a sequential extraction protocol and compared with a simple extraction at pH 6. Rheological properties of three okra extracts were then investigated by means of molecular weight determination, dilute solution rheology, steady shear and oscillatory rheological measurements. The extraction protocols resulted in extracts of relatively high purity and multimodal molecular weight distribution. Furthermore, molecular parameters of the isolated biopolymers such as intrinsic viscosity, Huggins constant, critical concentration and coil overlap parameter were calculated from dilute solution viscometry. Investigation of the generalized flow behaviour using a modified Cross equation and Cox-Merz plots showed evidence that as concentration increases specific interactions start taking place among the polymeric chains that modify the rheological behaviour of the extracts. The change in the rheological behaviour could not only be ...
TY - JOUR. T1 - Thermal, crystallization, and dynamic rheological behavior of wood particle/HDPE composites. T2 - Effect of removal of wood cell wall composition. AU - Ou, Rongxian. AU - Xie, Yanjun. AU - Wang, Qingwen. AU - Sui, Shujuan. AU - Wolcott, Michael P. PY - 2014/6/5. Y1 - 2014/6/5. N2 - This study investigated the effect of removal of wood cell wall composition on thermal, crystallization, and dynamic rheological behavior of the resulting high density polyethylene (HDPE) composites. Four types of wood particle (WP) with different compositions: native wood flour (WF), hemicellulose-removed wood particle (HR), lignin-removed wood particle (holocellulose, HC), and both hemicellulose and lignin removed particle (α-cellulose, αC) were prepared and compounded with HDPE using extruder, both with and without maleated polyethylene (MAPE). Results show that removal of the hemicellulose improved the thermal stability of composites, while removal of the lignin facilitated thermal decomposition. ...
With the ever increasing market demand for rubber products, those in compounding and manufacturing are tasked with the challenge of increasing output without sacrificing efficiencies. This naturally increases the requirements of processes such as mixing, extruding, and injection molding in the rubber industry. Many factors contribute to the success or failure of a compound formulation to meet the required processing and performance criteria. The physical and chemical properties of the raw polymer are among the most important, including molecular weight, molecular weight distribution, and the degree of long-chain branching. Rheological characterization is perhaps the most powerful technique for quickly and easily obtaining information about these properties, enabling process/production engineers and compounders invaluable information about processability of raw polymers and processed compounds. The talk provides an overview of basic and advanced rheological measurements using MDR and RPA ...
TY - BOOK. T1 - Rheology of Supramolecular Polymers. AU - Shabbir, Aamir. PY - 2016. Y1 - 2016. N2 - Supramolecular polymers are a broad class of materials that include all polymerscapable of associating via secondary interactions. These materials represent an emerging class of systems with superior versatility compared to classical polymers with applications in food stuff, coatings, cost efficient processes or biomedical areas. Design and development of supramolecular polymers using ionic, hydrogen bonding or transition metal complexes with tailored properties requires deep understanding of dynamics both in linear and non-linear deformations. While linear rheology is important to understand the dynamics under equilibrium conditions, extensional rheology is relevant during the processing or in the usage of polymers utilizing supramolecular associations for example, acrylic based pressure sensitive adhesives are subjected to extensional deformations during the peeling where strain hardening is ...
One of the room temperature ionic liquids (RTILs), 1-butyl-3-methylimidazoliumchloride ([BMIM]Cl) was chosen to prepare the concentrated solutions of Polyacrylonitrile(PAN). The rheological behaviors of the solutions were measured with rotational rheometryunder different conditions, including temperatures, concentration, and molecular weight ofPAN. The solutions exhibited shear-thinning behaviors, similar to that of PAN/DMFsolutions. The viscosities decreased with the increasing of shear rates. However, theviscosity decreased sharply at high shear rates when the concentration was up to 16wt%. Thedependence of the viscosity on temperature was analyzed through the determination of theapparent activation energy. Unusually, the viscosity of solutions of higher concentration islower than that of lower concentration. Similarly, the viscosity of low molecular weightPAN was higher than high molecular weight PAN at high shear rates. The dynamicrheological measurement indicates the loss modulus is much higher
Changes in rheological properties and amylase activities occurring in trifoliate yam, Dioscorea dumetorum, starch after harvest were investigated. Trifoliate yam tubers were harvested and stored under tropical ambient (28°C) and cold room conditions (4°C) for 12, 24 and 36 h. The D. dumetorum starches were extracted from the tubers under study and samples were evaluated for changes in their rheological properties (paste characteristics) during storage and to study the action of amylases on D. dumetorum starch after harvesting. The post-harvest activities of α and β-amylases were also studied to evaluate their rate of action on D. dumetorum starch. Storage caused decreases in the rheological properties (paste characteristics) of the tubers within 36 h of harvest. Similarly, α and β-amylase activities in the tubers more than doubled within 24 h after harvesting. Blanching, however, effectively decreased the action of amylases on D. dumetorum starch during storage, with subsequential increase ...
Two-dimensional in-cylinder velocity distributions measured with Particle Image Velocimetry were compared with computed results from Computational Fluid Dynamics codes. A high-swirl, two-valve, four-stroke transparent-combustion-chamber research engine was used. Comparisons were made of mean-flow velocity distributions, swirl-ratio evolution during the intake and compression strokes, and turbulence distributions at top-dead-center compression. This comparison with the measured flows led to more accurate calculations by identifying code improvements including swirl in the residual gas, modeling of the gas exchange during the valve overlap, and improved numerical accuracy ...
Dissertation abstracts: Rheological behaviour of system viscoelastic surface-active substance/assotsiirujushchy polymer and its components - Chemical sciences
Rheology (/riːˈɒlədʒi/; from Greek ῥέω rhéō, flow and -λoγία, -logia, study of) is the study of the flow of matter, primarily in a liquid state, but also as soft solids or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force. Rheology is the science of deformation and flow within a material. It is a branch of physics which deals with the deformation and flow of materials, both solids and liquids.[1] The term rheology was coined by Eugene C. Bingham, a professor at Lafayette College, in 1920, from a suggestion by a colleague, Markus Reiner.[2][3] The term was inspired by the aphorism of Simplicius (often attributed to Heraclitus), panta rhei, everything flows,[4][5] and was first used to describe the flow of liquids and the deformation of solids. It applies to substances that have a complex microstructure, such as muds, sludges, suspensions, polymers and other glass formers (e.g., silicates), as ...
Fingerprint Dive into the research topics of Influence of oxygen tension on the rheological behavior of sickle cells in microcirculation. Together they form a unique fingerprint. ...
A numerical study of hemodynamic parameters of pulsatile blood flow is presented in a stenotic artery with non-Newtonian models using ADINA. Blood flow was considered laminar, and arterial wall was considered rigid. Studied stenosis severities were 30%, 50% and 70% of the cross-sectional area of the artery. Six non-Newtonian models were used to model the non-Newtonian behavior of blood, and their results were compared with the Newtonian model. The results showed that in Power Law and Walburn-Schneck models, unlike other models, shear stress values before and after the stenosis were smaller than Newtonian models. Also, in maximum flow rate, the Carreua, generalized Power Law, Casson, and Carreua-Yasuda models showed a reduction in global importance factor of non-Newtonian behavior, and as a result, the results approached Newtonian model. In minimum flow rate, the global importance factor of Newtonian behavior increased, which highlighted the importance of Newtonian model. In minimum flow rate, Carreua
A numerical study of hemodynamic parameters of pulsatile blood flow is presented in a stenotic artery with non-Newtonian models using ADINA. Blood flow was considered laminar, and arterial wall was considered rigid. Studied stenosis severities were 30%, 50% and 70% of the cross-sectional area of the artery. Six non-Newtonian models were used to model the non-Newtonian behavior of blood, and their results were compared with the Newtonian model. The results showed that in Power Law and Walburn-Schneck models, unlike other models, shear stress values before and after the stenosis were smaller than Newtonian models. Also, in maximum flow rate, the Carreua, generalized Power Law, Casson, and Carreua-Yasuda models showed a reduction in global importance factor of non-Newtonian behavior, and as a result, the results approached Newtonian model. In minimum flow rate, the global importance factor of Newtonian behavior increased, which highlighted the importance of Newtonian model. In minimum flow rate, Carreua
Abstract. Rheologic properties of blood were studied in 8 patients with dilated cardiomyopathy (DCM) and in 10 healthy subjects. Whole-blood viscosity was measured at four different shear rates, by means of a computer-controlled rotational viscometer. The patients had significantly higher blood viscosity at all shear rates, both at their natural hematocrits and after an in vitro adjustment of sample hematocrits to 45%. Erythrocyte filterability (5 μm pore size) was significantly lower, fibrinogen concentration significantly higher, and HDLcholesterol concentration significantly lower in the patient group. No significant differences were found regarding hematocrit, mean corpuscular volume, haemoglobin concentration, leukocyte count and filterability (8 μm pore size), plasma viscosity, and total cholesterol concentration.. The measured hemorheologic abnormalities may contribute to the previously reported reduction of coronary blood flow reserve in DCM patients and to myocardial microcirculatory ...
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Lucideon provides rheological characterisation & viscosity measurements across the full range of shear rates encountered in production, from pouring or gentle mixing through to spraying & spinning
Within the present investigation, a miniature viscous disk pump (VDP) is utilized to characterize and quantify non-Newtonian fluid elastic turbulence effects, relative to Newtonian flow behavior. Such deviations from Newtonian behavior are induced by adding polyacrylamide to purified water. The VDP consists of a 10.16 mm diameter disk that rotates above a C-shaped channel with inner and outer radii of 1.19 mm and 2.38 mm, respectively. A channel depth of 230 μm is employed. Fluid inlet and outlet ports are located at the ends of the C-shaped channel. Experimental data are given for rotational speeds of 126 1/s, 188 1/s, 262 1/s, and 366 1/s, pressure rises as high as 700 Pa, and flow rates up to approximately 0.00000005 m3/s. Reynolds number ranges from 2.9 to 6.5 for the non-Newtonian polyacrylamide solution flows and from 51.6 to 149.8 for the Newtonian pure water flows. To characterize deviations due to non-Newtonian elastic turbulence phenomena, two new parameters are introduced, PrR and ...
Malvern rheometers and viscometers measure viscosity and viscoelasticity of complex fluids and biopharmaceutical formulations to soft condensed matter.
Non-physiologic turbulent flow occurs in medical cardiovascular devices resulting in hemodynamic stresses that may damage red blood cells (RBC) and cause hemolysis. Hemolysis was previously thought to result from Reynolds shear stress (RSS) in turbulent flows. A more recent hypothesis suggests that turbulent viscous shear stresses (TVSS) at spatial scales similar in size to RBCs are related to their damage. We applied two-dimensional digital particle image velocimetry to measure the flow field of a free-submerged axisymmetric jet that was utilized to hemolyze porcine RBCs in selected locations. Assuming a dynamic equilibrium for the sub-grid scale (SGS) energy flux between the resolved and the sub-grid scales, the SGS energy flux was calculated from the strain rate tensor computed from the resolved velocity fields. The SGS stress was determined by the Smagorinsky model, from which the turbulence dissipation rate and then TVSS were estimated. Our results showed the hemolytic threshold of the ...
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Interactions between organisms and complex flow fields are of significant consequence to many ecological processes (e.g. predator-prey interactions, swimming behavior, spatial dispersion and distribution, diel migration). Thus, turbulence-organism interactions have received much recent attention (e.g. Prairie et al., 2012; Guasto et al., 2012; Durham et al., 2013; Jumars et al., 2009; Yamazaki and Squires, 1996). Quantifying turbulent flow fields with high spatial and temporal resolution, and relating them to the behavior and distributions of organisms, e.g. zooplankton, is critical for advancing our understanding. However, obtaining such data is challenging. First, both turbulent flows and planktonic motion are unsteady and three-dimensional, requiring a time-resolved, volumetric measurement system; second, plankton can propel themselves relative to the surrounding fluid leading to local differences in fluid and organism velocity; and third, many planktonic organisms have ...
A high solids structured kaolin clay slurry having improved high shear rheology is manufactured by a process which comprises the sequential steps of forming an aqueous composition by mixing water and a lithium-based dispersant and then mixing structured kaolin clay particles with the aqueous composition to form the desired high solids slurry.
Elastic turbulence, which is sensitive to geometry and polymer rheology, has shown great potential for improving the performance of mixing, heat transfer, and even oil recovery. Recent studies showed the importance of the rheological properties of polymer solutions on the onset of elastic turbulence. However, variations of rheological properties based on polymer sensitivities such as salinity and its corresponding effects on the elastic turbulence have not been revealed. This work investigated systematically the effects of salinity on the onset of elastic turbulence in both swirling flow and curvilinear microchannels. The variations of statistical properties, such as probability distribution functions (PDFs) and power spectral density of injected power (PSD), were analyzed for characterization. The onset conditions of elastic turbulence are postponed by high salinity, which is consistent with the mixing performance in a curvilinear microchannel. A salinity independent power-law exponent at a ...
TY - JOUR. T1 - Comparison of original and cross-linked wormlike micelles of poly(ethylene oxide-b-butadiene) in water. T2 - Rheological properties and effects of poly(ethylene oxide) addition. AU - Won, You Yeon. AU - Paso, Kristofer. AU - Ted Davis, H.. AU - Bates, Frank S.. PY - 2001/9/6. Y1 - 2001/9/6. N2 - Chemical fixation can convert self-assembled amphiphilic aggregates into covalently bonded giant macromolecules that can have properties that are fundamentally different from the unreacted precursors. Following up our previous report, we here extend the comparison between pristine and cross-linked wormlike micelles prepared from a cross-linkable poly(ethylene oxide-b-butadiene) diblock copolymer. Despite retention of the overall morphology, the cross-linked wormlike micelles exhibit unusual linear and nonlinear flow properties that presumably reflect the micelle stiffening upon cross-linking. Chemical fixation also influences their responses to changes in thermodynamic conditions. To ...
Results of theoretical and experimental investigations, devoted to the analysis and optimization of optoelectronic image formation devices (IFD) on the basis of deformable polymer films (DPF) at the expense of choice of the polymer material rheology, electric field distribution in DPF by means of electrode raster and heat deformation regime is presented. For DPF structure investigations the tunnel electron microscopy technique has been used ...
Particle size analysis, zeta potential measurement, rheology, molecular weight and size measurement, size exclusion / gel permeation chromatography sec/gpc
DUBLINResearch and Markets (http://www.researchandmarkets.com/research/zdhptm/personal_care) has announced the addition of the Personal Care Ingredients Market by Type (Surfactants, Conditioning Polymers, Emollients, Rheology Modifiers and Others) and by Application (Skin Care, Hair Care, Oral Care and Others) -
Phlebs The failure of blood to clot, or coagulate, following serious bodily trauma or a surgical procedure is one of the leading causes of preventable death in patients. Now, a new optical device based on laser speckle rheology requires only a drop or two of blood and a few minutes to measure the key coagulation parameters that can guide medical...
Agarwal Deepa, MacNaughtan W., Foster T.J., (2018) Interactions between microfibrillar cellulose and carboxymethyl cellulose in an aqueous suspension. Carbohydrate Polymer, 185, 112-119.. Agarwal Deepa, Hewson L., Foster T.J. (2018) A comparison of the sensory and rheological properties of different cellulosic fibres for food. Food & Functions, in the press.. Agarwal Deepa, MacNaughan W., Foster T.J. (2015) Relaxation NMR and rheology in cellulosic materials. NMR workshop, The University of Nottingham, UK. (Talk). Agarwal Deepa, Foster T.J., (2014) Rheological Properties of highly refined cellulose: carboxymethyl cellulose Mixtures compared to other commercially available Fibres. Annual European Rheology conference (AERC), Karlsruhe, Germany. (Talk). Agarwal Deepa, Foster T.J., (2014) Investigation of the interaction between micro fibril cellulose and different polymeric additives in aqueous suspensions. 6th International conference on polymer behaviour (ICPB (6)), Vienne, Austria. ...
A multitude of consumer products, especially foods, owe their structure, stability and function to the presence of interfaces. Common examples include foams and emulsions such as milk, soups, salad dressings, mayonnaise, ice cream and butter (see McClements [1] and references therein). Although many of these foams and emulsions are thermodynamically unstable, the kinetics of phase separation can be controlled with the addition of various proteins, surfactants, gums and other stabilizing agents, which have very important implications for the shelf life of foods [2]. However, the presence of these additives often leads to complex rheological properties and gives rise to distinctive power laws in the creep response (i.e. the strain varies as γ(t)∼tα) and also in the corresponding frequency response (i.e. the elastic modulus varies with frequency as G′(ω)∼ωα). Such power-law responses are not well described by canonical rheological models such as the Maxwell or Kelvin-Voigt models [3]. ...
In my thesis, I studied three problems involving E. Coli bacterial suspensions. Firstly, I focused on the Brownian motion of passive tracers in this particular active suspension close to a surface. Buoyancy and non-buoyancy swimming solutions were tested, revealing a linear increase of the passive tracer diffusion with the active flux, obtained by the active concentration of bacteria multiplied by the mean velocity. Boundary confinements were also explored in buoyancy conditions, showing a better momentum transfer of the active bacteria as the height of the confinement gets smaller. The use of artificial swimmers instead of bacteria also leads to similar results in the enhancement of the diffusion. Secondly, I considered the modification of the fluid viscosity caused by the presence of these self-propelling entities. It is known that for pusher swimmers as bacteria the viscosity can even be smaller than that of the suspending fluid viscosity. The lack of experimental result showing this effect in the
The present study reports on the development of multifunctional plaster showing superior thermal insulation, ability to control the indoor RH and NOx photocatalytic degradation. The plaster contains TiO2 nanoparticles (1 wt.%) and 0-4 wt.% fibers of two distinct sizes: 1 mm < d < 2 mm (Fb(1-2mm)) and 2 mm < d < 4mm (Fb(2-4mm)). The formulations were adjusted based on flow table and rheometer tests, aiming to assure a desirable workability. Plasters with similar workability (spread on table) showed distinct yield stress values over time and Fb((1-2mm)) plays an important role on the workability control. Rheological behaviour was governed by Fb((2-4mm)). Binary mixture 2.0Fb(1-2mm) + 2.0Fb(2-4mm)2.0Fb(2-4mm) required less water amount to show the same workability of the single formulation 4.0Fb(1-2mm). However, the control of the rheological behavior over time was found difficult. The apparent porosity, water absorption and capillary index were strongly incremented with the rise of cellulose fiber
Resistance to blood flow through peripheral vascular beds strongly influences cardiovascular function and transport to tissue. For a given vascular architecture, flow resistance is determined by the rheological behavior of blood flowing through microvessels. A new approach for calculating the contribution of blood rheology to microvascular flow resistance is presented. Morphology (diameter and length), flow velocity, hematocrit, and topological position were determined for all vessel segments (up to 913) of terminal microcirculatory networks in the rat mesentery by intravital microscopy. Flow velocity and hematocrit were also predicted from mathematical flow simulations, in which the assumed dependence of flow resistance on diameter, hematocrit, and shear rate was optimized to minimize the deviation between measured and predicted values. For microvessels with diameters below approximately 40 microns, the resulting flow resistances are markedly higher and show a stronger dependence on hematocrit ...
This series of notes have their origin into accelerated course in optimal control given to multidisciplinary Phd students in Mathematics, Physics or Control Engineering and the purpose is to present the seminal results of this theory in view of applications to concrete problems. For that we choose to make the presentation using two real life applications which are the core of current research projects on the academic side and motivated by industrial applications. The two applications concern the swimming at low Reynolds number and the contrast problem in Magnetic Resonance Imaging.
Most of the materials, in general, are neither purely elastic nor purely viscous; they exhibits both elastic property (revealing its capability to store mechanical energy) and viscous property (manifesting its characteristic to dissipate energy, often in the form of heat). The study of the complex viscoelastic property of matter is known as rheology. Macro-rheology, or synonymously, classical rheometry, for the measurement of the bulk-average viscoelastic property of a material via a conventional rheometer often expresses the results in terms of either the magnitude of the complex viscosity|*|or both the real part () which is related to the elastic property and the imaginary part () which is related to the viscous property, both in the units of Pascal sec. (or poise; 1 poise = 0.1 Pa sec.), as a function of the shear rate. Likewise, micro-rheology allows us to probe the localized rheological properties of soft matter (often liquid) with one or more micron-size particles with a ...
Flow Properties of Lambda Carrageenan in Aqueous Systems. By Andrea Rivera del Rio, Mariana Ramírez-Gilly and Alberto Tecante. Small amplitude oscillatory and steady shear measurements at 25°C were used to investigate the rheological behavior of λ‐carrageenan solutions at pH 7.0 ± 1.0 without and with added sodium counterion. The dynamic moduli, G′(ω) and G″(ω), show the typical behavior of macromolecular solutions in which the viscous character predominates. The steady shear flow exhibits a Newtonian zero‐shear viscosity (η0) region followed by a shear‐thinning zone. Viscosity data can be well described by the Carreau‐Yasuda model. Without added Na+, the intrinsic viscosity, [η], and the critical overlap concentration, C*, are 204 dL/g and 0.21%, respectively. With 20 mmol/dm3 Na+, [η] = 14.7 dL/g and C* = 0.38%. For concentrations below C*, the viscous character is more sensitive to the presence of added Na+, and the opposite occurs when the concentration exceeds C*. The ...
Decellularized tissues composed of extracellular matrix (ECM) and used as biologic scaffolds, have been shown to be useful for the repair of a variety of tissues. The clinical utility of such scaffolds for the tissue engineering of Nucleus Pulposus (NP) might be large but limited by the surgical procedure necessary to implant the engineered tissue. An injectable gel form of the ECM could potentially conform the required three-dimensional shape and could be delivered to site of interest by minimally invasive techniques. The goal of this project is to design a gel form of ECM scaffold, prepared from decellularized bovine NP that has been powdered. The work will include the evaluation of the gel to support in vitro growth of bovine NP-cells and the rheological characterization of its properties. Grimm, Alizée; Abdel-Sayed, Philippe
An in situ gelled scaffold for bone tissue engineering to restore the function of bone tissues is developed. The gel is comprised of Pluronic F127 and chitosan. The gelation temperature (Tgel), and viscoelastic properties and mucoadhesive force of the systems were investigated by means of rheological analyses. At specific concentrations, the hydrogel exhibited a Tgel close to the body temperature due to the addition of chitosan. Mucoadhesion experiments showed a rheological synergism between F127/chitosan gels and mucin dispersion, and a change in the flow behavior. In vitro release results indicated that the optimized gel was able to prolong and control acyclovir release for more than 20 min. Based on cell proliferation assay, the gel exhibited biocompatibility for osteoblasts.
This work presents a new technique of the passive microrheology for the study of the microstructure properties of soft materials.
A method is presented to calibrate the transfer function for a fluid-filled compliant cylinder as a function of wavenumber and frequency. An air-filled compliant cylinder has a first linear array of force sensors coupled to the cylinders exterior surface. A turbulent flow field is generated in a fluid environment about the first linear array which generates an output indicative of pressure incident thereupon. A fluid-filled compliant cylinder identical in diameter to the air-filled compliant cylinder houses a second linear array of force sensors. A similar turbulent flow field is generated in the fluid environment about the fluid-filled complaint cylinder to generate an output indicative of pressure incident upon the second linear array. The ratio of outputs is indicative of the transfer function of the fluid-filled compliant cylinder. Each output can be further adjusted by a calibrated sensitivity of the corresponding first and second linear arrays. The method compensates for elastic scattered
We present a new application of optical coherence tomography (OCT), widely used in biomedical imaging, to flow analysis in near-wall hydrodynamics for marine research. This unique capability, called OCT micro-particle image velocimetry, provides a high-resolution view of microscopic flow phenomena and measurement of flow statistics within the first millimeter of a boundary layer. The technique is demonstrated in a small flow cuvette and in a water tunnel.. © 2013 Optical Society of America. Full Article , PDF Article ...
Purpose: : The aim of this study is to show a correlation between cohesive and rheologically measured properties for OVDs and also to show the existence of a transition interval in molecular masses where there is a gradual change from cohesive to dispersive behavior. Methods: : A number of formulations of sodium hyaluronate (HA) in phosphate buffer differing in concentration and molecular mass were made and characterized rheologically. All solutions were formulated to belong to the concentrated regime, i.e. above the critical concentration c* (Simha et al) for each molecular mass. Experimental data for sample formulations were compared to published data for some commercial formulations (Poyer et al). The oscillatory tests were performed in a Physica MCR 300 rheometer with a cone-plate arrangement (CP 25-1). The measurements were performed in the LVE (linear viscoelastic region) under controlled shear deformation (CSD). The elastic, G, and the viscous moduli, G, were analyzed as a function ...
Plastics are amazing materials with the unique ability to flow when heated to relatively low temperatures. They can be formed into a wide variety of shapes and tailored for many different applications. However, their flow properties during this process are complex and affected by many parameters. Instron® provides comprehensive and effective testing solutions in plastics applications and industries through the CEAST SmartRHEO Series. This capillary rheometer simulates the process conditions, measuring the plastic materials flow behavior that characterizes the rheology of materials.. ...
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Non-Newtonian and Newtonian blood flow in human aorta: A transient analysis, Kumar D, Vinoth R, Raviraj Adhikari, Vijay Shankar CS
A capillary rheometer is an apparatus designed to measure shear viscosity and other rheological (= flow) properties. Capillary rheometers for plastics are piston-die systems designed to measure viscosity of polymer melts as a function of temperature and rate of deformation. They are capable of testing basic polymers, compounds, various composites with small reinforcing particles or fibers, feedstock for metal injection molding and similar materials.. The basic principle is that a thermoplastic sample (originally in the shape of granules, powder or flakes) is made fluid by heating and forced to flow out of a cylinder through a capillary die. The measured quantity is normally the generated pressure under steady state conditions. A flow curve is the typical output, obtained by interpolation of several experimental data. Viscosity is represented as the Greek letter eta (η) and expressed (in SI units) in pascal seconds (Pa·s) or newton seconds per square meter (N·s/m2).. Capillary rheometers ...
SETZ, L. F. G.; KOSHIMIZU, L.; PARDO, A. R. F. y MORELLI, M. R.. Rolling study of ceramic substrates from concentrate alumina suspensions. Cerâmica [online]. 2011, vol.57, n.344, pp.409-415. ISSN 0366-6913. http://dx.doi.org/10.1590/S0366-69132011000400006.. The ceramic substrates production by calendering, or viscous plastic processing, is interesting because inherent problems as a powder agglomeration is minimized. When the ceramic pastes shaping for this technique are produced from stabilized suspensions these problems almost inexist. This work presents the concentrate suspensions and pastes with different hydroxypropyl methyl cellulose (HPMC) thickener content rheological behaviors. The variables involved in calendering shaping were studied, too. The production of dense alumina substrates shaped by calendaring from concentrate suspensions (60 vol.%), stabilized with 0.02 wt.% Viscocrete 20HE and 1.5 wt.% HPMC is possible.. Palabras clave : rheology; ceramic substrates; calendering. ...