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Wyniki wyszukiwania dla: SHEAR-THINNING FLIUD
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Acoustic Heating Produced in the Thermoviscous Flow of a Shear-Thinning Fluid
PublikacjaThis study is devoted to the instantaneous acoustic heating of a shear-thinningfluid. Apparent viscosity of a shear-thinning fluid depends on the shear rate. Thatfeature distinguishes it from a viscous Newtonian fluid. The special linear combi-nation of conservation equations in the differential form makes it possible to derivedynamic equations governing both the sound and non-wave entropy mode inducedin the field of sound. These...
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2D numerical simulation of tear film dynamics: Effects of shear-thinning properties
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Injectable poloxamer/graphene oxide hydrogels with well‐controlled mechanical and rheological properties
PublikacjaAlthough significant progress has been made in the design and application of injectable hydrogels for biomedical applications, concurrent control of rheological and mechanical properties of injectable hydrogels has remained as an open challenge to the researchers. In this work, we introduce and put into practice a photo‐curable poloxamer (also known as Pluronic)/graphene oxide (Plu/GO) injectable hydrogel with well‐controlled rheological...
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GENERALISED HERSCHEL MODEL APPLIED TO BLOOD FLOW MODELLING
PublikacjaThis paper introduces a new rheological model of blood as a certain generalisation of the standard Herschel-Bulkley model. This model is a rheological constitutive equation and belongs to the group of the so-called generalised Newtonian fluids. Experimental data is compared with results, obtained from the new model, to demonstrate that it allows for the best agreement together with Luo-Kuang model. The new model may be easily implemented...
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Comparitive study of heat transfer and pressure drop during flow boiling and flow condensation in minichannels
PublikacjaIn the paper a method developed earlier by authors is applied to calculations of pressure drop and heat transfer coefficient for flow boiling and also flow condensation for some recent data collected from literature for such fluids as R404a, R600a, R290, R32,R134a, R1234yf and other. The modification of interface shear stresses between flow boiling and flow condensation in annular flow structure are considered through incorporation...
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Influence of addition of carbon nanotubes on rheological properties of selected liquid lubricants - a computer simulation study
PublikacjaThis work is motivated by the improvement of anti-friction properties of lubricants by addition of CNTs proved experimentally in literature. In particular, a methodology is developed to compute the shear viscosity of liquid lubricants (Propylene Glycol) based on Molecular Dynamics simulation. Non-Equilibrium molecular dynamics (NEMD) approach is used with a reactive force field ReaxFF implemented in LAMMPS. The simulations are...
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Analytical model with non-adiabatic effects for pressure drop and heat transfer during boiling and condensation flows in conventional channels and minichannels
PublikacjaIn the paper a method developed earlier by authors is applied to calculations of pressure drop and heat transfer coefficient for boiling flow and condensation flow with account of non- adiabatic effects for some recent data collected from literature. The first effect, the modification of interface shear stresses in annular flow pattern is considered through incorporation of the so called "blowing parameter". The mechanism of...
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Study of Non-Newtonian biomagnetic blood flow in a stenosed bifurcated artery having elastic walls
PublikacjaFluid structure interaction (FSI) gained attention of researchers and scientist due to its applications in science felds like biomedical engineering, mechanical engineering etc. One of the major application in FSI is to study elastic wall behavior of stenotic arteries. In this paper we discussed an incompressible Non-Newtonian blood fow analysis in an elastic bifurcated artery. A magnetic feld is applied along x direction. For...
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Fluid structure interaction study of non-Newtonian Casson fluid in a bifurcated channel having stenosis with elastic walls
PublikacjaFluid–structure interaction (FSI) gained a huge attention of scientists and researchers due to its applications in biomedical and mechanical engineering. One of the most important applications of FSI is to study the elastic wall behavior of stenotic arteries. Blood is the suspension of various cells characterized by shear thinning, yield stress, and viscoelastic qualities that can be assessed by using non-Newtonian models. In this...
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Rheology of potato starch chemically modified with microwave-assisted reactions
PublikacjaNative potato starch was sulfated, selenated, borated, silicated and zincatated by means of microwave-assisted reactions with varying doses of relevant reagents. Resulting products were characterized involving rheological behavior of pastes, their weight-average molecular weight (Mw), and radius of gyration (Rg). Most of the pastes showed shear-thinning behavior, with the flow behavior index (n) below unity. The pastes of starch...
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Development and evaluation of thermosensitive hydrogels with binary mixture of Scutellariae baicalensis radix extract and chitosan for periodontal diseases treatment.
PublikacjaScutellaria baicalensis root displays anti-inflammatory and antibacterial properties due to the presence of flavonoids, particularly baicalin, baicalein, and wogonin. Our work aimed at developing thermosensitive hydrogels containing a binary mixture of S. baicalensis radix lyophilized extract and chitosan as a novel approach for periodontal diseases treatment....
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Fruit seeds oils as a cosmetic emulsions component
PublikacjaThe fruit seeds are known to have a considerable amount of oil and their potential specialty as nutraceutical oil was suggested based on high level of unsaturated triacyglycerols (major fatty acids are linoleic, linolenic, oleic) and a high content of tocols (tocopherols and tocotrienols). In this study the possibility of application fruit seeds oils in W/O and O/W emulsion systems was investigated to find the influence of the...
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Practical aspects of Flow Thinning optimization
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Verification of punching shear outside the shear cap by the direct method
PublikacjaThe proposition of a method to verify the punching resistance for very large supports based on the EN 1992-1-1 standard is described in this paper. The present standard guidelines for the calculation of the punching resistance for large supports are also summarised. The proposed direct method is compared with other standard methods using an example taken from design practice. This method consists of a direct check of the shear...
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Influence of the Shear Cap Size and Stiffness on the Distribution of Shear Forces in Flat Slabs
PublikacjaThe scope of this paper is to investigate analytically and numerically the influence of shear cap size and stiffness on the distribution of shear forces in flat slabs in a slab–column-connections-reinforced concrete structure. The effect of support (shear cap) stiffness on the calculation of the length of the shear control perimeter according to the available methods is presented. Based on the analysis, the authors indicate in...
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Shear band evolution phenomena in direct shear test modelled with DEM.
PublikacjaA direct shear test is widely used in the geotechnical engineering field. It is an easy and quick test to measure the shear properties of soil. This test often replaces more expensive and difficult tri-axial shear test. Despite that the direct shear test is known and used for a long time, it is still not well investigated at the grain scale. This paper deals with the micro behaviour of the cohesionless sand inside the direct shear...
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Thinning Methods to Regulate Sweet Cherry Crops—A Review
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Thinning as Method to Regulate Sweet Cherry Crops – a Review
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The Influence of Shear Deformation in analysis of plane frames
PublikacjaThe focus of the paper is to investigate the influence of shear deformation effect on the distribution of internal forces and frame deformation. To estimate shear deformation effect, the Timoshenko beam theory and the concept of shear deformation coefficients are used. Analysis of example frames gives the possibility to evaluate what have the most impact on size of shear deformation and in which type of frames the shear deformation...
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Shear resistance of low height precast concrete lintels
PublikacjaThe scope of the paper is to investigate analytically and determine experimentally the shear resistance of low height reinforced precast concrete lintels. The chosen procedures included in national and international standards applied for the design of structural concrete elements to an estimation of shear behaviour of reinforced concrete elements are described. The characteristic and designed shear strength of precast concrete...
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Characterization of the Functionally Graded Shear Modulus of a Half-Space
PublikacjaIn this article, a method is proposed for determining parameters of the exponentialy varying shear modulus of a functionally graded half-space. The method is based on the analytical solution of the problem of pure shear of an elastic functionally graded half-space by a strip punch. The half-space has the depth-wise exponential variation of its shear modulus, whose parameters are to be determined. The problem is reduced to an integral...
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Determination of Changes in Viscosity of Hydrogel Depending on Shear Rates
PublikacjaThe datasets entitled Determination of changes in viscosity of hydrogel depending on shear rate contain the results of viscosity measurements using a Brookfield viscometer, with different kinds of spindles and shear rates. The data allowed the used hydrogel preparations to be characterised and their functional parameters, as substances modifying the rheology of thickeners and determining the effect of shear rate on the viscosity...
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Improving of Cherry Fruit Quality and Bearing Regularity by Chemical Thinning with Fertilizer
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Identification of Shear Modulus Parameters of Half-space Inhomogeneous by Depth
PublikacjaThe paper propose a method for determining of the parameters of the exponential shear modulus of a functionally graded half-space based on the solution of the problem of a pure shear of an elastic functionally graded half-space by a strip punch. The solution of the integral equation of the contact problem is constructed by asymptotic methods with respect to the dimensionless parameter. The dependence of contact stresses on the...
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Analyses of Shear Angle in Orthogonal Cutting of Pine Wood
PublikacjaThe determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The...
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Temperature influences on shear stability of a nanosize plate with piezoelectricity effect
PublikacjaPurpose The purpose of this paper is to predict the mechanical behavior of a piezoelectric nanoplate under shear stability by taking electric voltage into account in thermal environment. Design/methodology/approach Simplified first-order shear deformation theory has been used as a displacement field. Modified couple stress theory has been applied for considering small-size effects. An analytical solution has been taken into account...
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A study on transverse shear correction for laminated sandwich panels
PublikacjaThe paper presents a study on an application of the First Order Shear Deformation Theory in a linear static analysis of elastic sandwich panels. A special attention has been given to the issue of the transverse shear correction. Two benchmark examples of sandwich plate problems with known reference solutions have been selected for a comparative analysis performed with own Finite Element codes. Interesting results allowed for drawing...
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Electro-mechanical shear buckling of piezoelectric nanoplate using modified couple stress theory based on simplified first order shear deformation theory
PublikacjaThis paper studies the electro-mechanical shear buckling analysis of piezoelectric nanoplate using modified couple stress theory with various boundary conditions.In order to be taken electric effects into account, an external electric voltage is applied on the piezoelectric nanoplate. The simplified first order shear deformation theory (S-FSDT) has been employed and the governing differential equations have been obtained using...
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Flexomagneticity in buckled shear deformable hard-magnetic soft structures
PublikacjaThis research work performs the first time exploring and addressing the flexomagnetic property in a shear deformable piezomagnetic structure. The strain gradient reveals flexomagneticity in a magnetization phenomenon of structures regardless of their atomic lattice is symmetrical or asymmetrical. It is assumed that a synchronous converse magnetization couples both piezomagnetic and flexomagnetic features into the material structure....
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Determination of changes in viscosity of hydrogel depending on shear rate (6.6 to 330 s-1).
Dane BadawczeThe rheological characteristics of hydrogel were made on the basis of a viscosity measurement using a Brookfield viscometer, using LV SC4 - 18 spindle and shear rates from 6.6 to 330 s-1.
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Load introduction to composite columns revisited—Significance of force allocation and shear connection stiffness
PublikacjaThe AISC 360-16 Specification recommends that the design shear force between parts of a composite column in the load introduction area shall be calculated based on the force allocation at ultimate limit state. Applicability of this straightforward method to the load levels that usually arise in slender composite columns is questionable, as this capacity-based force allocation is only true when the axial force is equal to the plastic...
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Direct shear stress vs strain relation for fiber reinforced composites
PublikacjaThe majority of fiber reinforced composites exhibit strong non-linear behavior in in-plane shear state. The effect is attributed to the micro-cracks appearing in the matrix and can be modeled on the micro and macro level. In this work the author proposes constitutive laws describing the non-linear in-plane shear response, which can be alternative for the relations commonly considered in the literature. The proposed equations are...
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Verification of Selected Calculation Methods Regarding Shear Strength in Reinforced and Prestressed Concrete Beams
PublikacjaThe purpose of this article was an attempt to compare selected calculation methods regarding shear strength in reinforced and prestressed concrete beams. Several calculation methods were tested. This included codes: PN-EN 1992-1-1:2008 [1], ACI 318- 14 [2] and fib Model Code for Concrete Structures 2010 [3]. The analysis also consists of methods published in technical literature. Calculations of shear strengths were made based...
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Verification of selected calculation methods regarding shear strength in beams without web reinforcement
PublikacjaThe purpose of the article was to compare selected calculation methods regarding shear strength in reinforced concrete beams without web reinforcement. Several calculation methods were tested. This included codes: PN-EN 1992-1-1:2008, ACI 318-14 and fib Model Code for Concrete Structures 2010. The analysis also consists of authorial methods published in technical literature. Calculations of shear strengths were made based on experimental...
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In-plane shear nonlinearity in failure behavior of angle-ply laminated shells
PublikacjaThe paper concerns the progressive failure analysis of laminates with the in-plane shear nonlinearity accounted for.The nonlinear shear response of the layer is described by the constitutive relation treating the stresses as a function of strains. Thus it can be easily incorporated into the displacement-based FEM codes. The brittle failure mechanisms of the fibers and the matrix of the layer are recognized with the use of the Hashin...
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Simulations of Shear Zones and Cracks in Engineering Materials Using eXtended Finite Element Method
PublikacjaNumerical simulations of cracks and shear zones in quasi-brittle materials are presented. Extended Finite Element Method is used to describe both cracks and shear zones. In a description of tensile cracks, a Rankine criterion is assumed. A discrete Mohr-Coulomb law is adopted for simulations of shear zones. Results of simple numerical tests: unixial tension, bending and biaxial compression are demonstrated.
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Influence of sheet/purlin fasteners spacing on shear flexibility of the diaphragm
PublikacjaThe paper presents the influence of sheet/purlin fasteners location (in reference to trapezoidal profile cross section) on shear flexibility of the cladding acting as a diaphragm. Analytical procedures were presented and their limitations were discussed. Next, selected schemes of fasteners location, known from engineering practice, but not included in European codes and recommendations, were analysed numerically in order to observe...
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Determination of changes in viscosity of chitosan solutions depending on shear rate.
Dane BadawczeThe rheological characteristics of chitosan solutions were based on viscosity measurements using a Brookfield viscometer, using LV SC4 - 25 spindles and shear rates from 4 to 53 s-1 (Fig. 1). Chitosan solutions with different molecular weights (low, medium and high) were prepared in concentrations from 1.5 to 3.0% in 0.5M acetic acid. The data allowed...
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Discrete Modelling of Micro-structural Phenomena in Granular Shear Zones
PublikacjaThe micro-structure evolution in shear zones in cohesionless sand for quasi-static problems was analyzed with a discrete element method (DEM). The passive sand failure for a very rought retaining wall undergoing horizontal translation towards the sand backfill was discussed. To simulate the behaviour of sand, the spherical discrete element model was used with elements in the form of rigid spheres with contacts moments.
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Comparative modeling of shear localization in granular bodies with FEM and DEM
PublikacjaThe intention of the paper is to compare the calculations of shear zones in granular bodies using two different approaches: a continuum and a discrete one. In the first case, the FEM based on a micro-polar hypoplastic constitutive law was used. In the second case, the DEM was taken advantage of, where contact moments were taken into account to model grain roughness. The comparative calculations were performed for a passive case...
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Optimized Computational Intelligence Model for Estimating the Flexural Behavior of Composite Shear Walls
PublikacjaThis article presents a novel approach to estimate the flexural capacity of reinforced concrete-filled composite plate shear walls using an optimized computational intelligence model. The proposed model was developed and validated based on 47 laboratory data points and the Transit Search (TS) optimization algorithm. Using 80% of the experimental dataset, the optimized model was selected by determining the unknown coefficients of...
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Estimation of fracture toughness and shear yield stress of orthotropic materials in cutting with rotating tools
PublikacjaThe cutting force is an energetic effect of splitting material, and might be considered from a point of view of modern fracture mechanics. Forecasting of the shear plane angle in cutting broaden possibilities for modelling of the cutting process even for thin uncut chips. Such mathematical model has been developed here for description of the orthotropic materials’ cutting on the base of fracture theory, and includes work of separation...
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Shear Cap Size Selection Method Based on Parametric Analysis of ACI-318 Code and Eurocode 2 Standard
PublikacjaThe scope of the paper is to propose a method for determining the size of shear caps in a slab–column-connections-reinforced concrete structure. Usually, shear heads are used to enhance slab–column connection, especially when the transverse reinforcement does not give the required punching shear load capacity. The dimensions of the shear head should provide the punching shear resistance of the connection inside and outside the...
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A shear stress micromodel of urinary tract infection by the Escherichia coli producing Dr adhesin
PublikacjaIn this study, we established a dynamic micromodel of urinary tract infection to analyze the impact of UT-segment-specific urinary outflow on the persistence of E. coli colonization. We found that the adherence of Dr+ E. coli to bladder T24 transitional cells and type IV collagen is maximal at lowest shear stress and is reduced by any increase in flow velocity. The analyzed adherence was effective in the whole spectrum of physiological...
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Determination of viscosity changes of protein hydrolyzate solutions depending on shear rate
Dane BadawczeRheological characteristics of connective tissue protein solutions were made on the basis of viscosity measurement using a Brookfield viscometer using LV SC4 - 27 spindles and shear rate of 85 s-1 (Fig. 1). Solutions of protein hydrolysates with a concentration of 2% in 0.5M acetic acid were prepared.
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Determination of changes in viscosity of chitosan cosmetic preparations depending on shear rate.
Dane BadawczeThe rheological characteristics of chitosan were made on the basis of a viscosity measurement using a Brookfield viscometer, using LV SC4 - 25 spindles and shear rates from 0.3 to 32 s-1 (Fig. 1). Chitosan solutions at 1% concentrations in acetic acid were prepared. The samples were subjected to storage tests.
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Numerical Modelling of Shear Localization in Granular Bodies using MPM and Non-local Hypoplasticity
PublikacjaThe paper deals with modelling of shear localization in granular bodies by means of an enhanced hypoplastic constitutive model and material point method (MPM). The calculations were carried out for plane strain compression of non-cohesive sand. In order to properly capture the width and inclination of shear zones, the constitutive model was enriched by a characteristic length of micro-structure by means of a non-local theory....
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Determination of changes in viscosity of hydrogel depending on shear rate (1.1 to 55 s-1).
Dane BadawczeThe rheological characteristics of hydrogel were made on the basis of a viscosity measurement using a Brookfield viscometer, using LV SC4 - 25 spindle and shear rates from 1.1 to 55 s-1.
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Determination of changes in viscosity of hydrogel depending on shear rate (1.7 to 34 s-1).
Dane BadawczeThe rheological characteristics of hydrogel were made on the basis of a viscosity measurement using a Brookfield viscometer, using LV SC4 - 27 spindle and shear rates from 1.7 to 34 s-1.
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Shaft friction from the DMT and direct shear interface tests
PublikacjaThe article presents preliminary attempt to create tri-linear transfer curves for describing pile behaviour under axial loading. Transfer curves would use the parameter measured in dilatometer test, particularly a constrained modulus MDMT. The proposed method is based on concrete rough and smooth interface tests performed in a direct shear apparatus. Based on the obtained mobilization curves, relationships were created between...