Preparation of Polycarboxylate-based Superplasticizer and Its Effects on Zeta Potential and Rheological Property of Cement Paste

A series of polycarboxylate-based superplasticizers(PCs) with different structures were synthesized and the effects of chemical structure on zeta potential and rheological property of cement paste were studied. Residual monomers in each sample of PCs were quantitatively determined. The property of the polymers in cement was tested by micro-electrophoresis apparatus and R/S rheometer. Results showed that the zeta potential and its rheological properties are related with the side-chain length and density of PCs. The PCs having shorter side chain and lower side chain density exhibit higher anionic charge density, thus resulting in higher zeta potential. The effect of side chain density on zeta potential is more notable compared with that of side-chain length, and thus affecting the initial shear yield stress and apparent viscosity of the cement paste. In addition, although increasing the side chain length will result in reduction of the anionic charge density, the steric hindrance effect is obvious, which can effectively improve the dispersion of the cement particles, and reduce the viscosity and shear yield stress of slurry.

Orientation distribution of fibers and rheological property in fiber suspensions flowing in a turbulent boundary layer

A model relating the translational and rotational transport of orientation distribution function （ODF） of fibers to the gradient of mean ODF and the dispersion coefficients is proposed to derive the mean equation for the ODE Then the ODF of fibers is predicted by numerically solving the mean equation for the ODF together with the equations of turbulent boundary layer flow. Finally the shear stress and first normal stress difference of fiber suspensions are obtained. The results, some of which agree with the available relevant experimental data, show that the most fibers tend to orient to the flow direction. The fiber aspect ratio and Reynolds number have significant and negligible effects on the orientation dis- tribution of fibers, respectively. The additional normal stress due to the presence of fibers is anisotropic. The shear stress of fiber suspension is larger than that of Newtonian solvent, and the first normal stress difference is much less than the shear stress. Both the additional shear stress and the first normal stress difference increase with increasing the fiber concentration and decreasing fiber aspect ratio.

Effects of temperature change on the rheological property of modified multiwall carbon nanotubes

Solvent-free nanofluids hold promise for many technologically significant applications.The liquid-like behavior,a typical rheological property of solvent-free nanofluids,has aroused considerable interests.However,there has been still lack of efficient methods to predict and control the liquid-like behavior of solvent-free nanofluids.In this paper,we propose a semi-discrete dynamic system with stochastic excitation describing the temperature change effects on the rheological property of multiwall carbon nanotubes(MWCNTs)modified by grafting sulfonic acid terminated organosilanes as corona and tertiary amine as canopy,which is a typical covalent-type solvent-free nanofluid system.The vibration of the grafting branches is simulated by employing a structure-preserving approach,and the shear force of grafting branches at the fixed end is computed subsequently.By taking the shear forces as an excitation acting on the MWCNTs,the axial motion of the MWCNTs is solved with the 7-point Gauss-Kronrod quadrature rule.The critical temperature associated with the appearance of the liquid-like behavior as well as the upper bound of the moving speed of the modified MWCNTs is determined,which can be used to predict and control the liquid-like behavior of the modified MWCNTs in engineering applications.

High Temperature Rheological Performance of Graphene Modified Rubber Asphalt

To elucidate the high temperature rheological capability of graphene modified rubber asphalt,three contents of graphene and crumb rubber were prepared by a combination of mechanical agitation and high speed shearing machine,then used dynamic shear rheological test(DSR)and multiple stress creep recovery(MSCR)tests to evaluate.The hardness and softening point with rotational viscosity of samples raised with the addition of graphene,especially the addition of 0.04%.Dynamic shear rheological test revealedthat the dynamic shear modulus G*,rutting factor G*/Sin δ,and zero shear viscosity(ZSV)of graphene-modified rubber asphalt were greatly influenced along with graphene-increased,on the contrary,phase angle δ which characterize the viscoelastic ratio of asphalt decreased.Multiple stress creep recovery(MSCR)tests showed that the graphene-enhanced rubber asphalt had high-temperature stability through non-recoverable creep compliance(Jnr).Based on these findings,graphene-modified rubber asphalt binders with the addition of 0.04% graphene had good viscoelastic properties as well as high temperature rutting resistance performance.In the meantime,G*/Sin δ,ZSV,and Jnr100,Jnr3200 have good correlation,which can reveal the excellent high-temperature stability performance of asphalt.

Effect of Xiaoke Granule(消渴冲剂) on Blood Sugar and Blood Rheological Property in Experimental Diabetic Animals

Objective:To study the pharmacological effect of Xiaoke Granule (XKG, 消渴冲剂) on blood sugar and blood rheological property in the diabetic animals.Methods: Alloxan induced diabetic mice or rats were grouped randomly. The effects of XKG on blood sugar, appetite, capacity of drinking, glucose tolerance, blood lipid and blood rheological property were observed and compared among groups.Results:XKG showed a trend in reducing the appetite and capacity of drinking, increasing the body weight, and significantly inhibiting the increase of blood sugar coused by ectogenic glucose in mice, and could improve the blood lipid and blood rheological property in rats.Conclusion:XKG is effective in reducing serum total cholesterol, lowering the blood viscosity, improving the blood rheological property of alloxan induced diabetic animals. Therefore, it might effective in treating and preventing the occurrence of diabetes mellitus and the complications of blood stasis.

Influence of rheological characteristics on the fluidization catastrophe of tailings flows

Limited by mining technology,mineral exploitation can produce large amounts of tailings.Heavy summer rainfall or seasonal freeze-thaw can lead to physical and chemical modification of tailing material in mountainous areas,resulting in fluidized tailings flow and severe disaster losses.Therefore,aiming at the problem of tailings fluidization catastrophe,this paper tried to reveal the rheological mechanism of tailings fluidization transformation by combining rheological tests and theoretical analysis.The results show that the yield stress increases with decreasing temperature,and when the density of debris flow(ρ)is more than 1.9 g/cm~3,this behavior becomes more pronounced as the density increases.The storage modulus decreases by at least two orders of magnitude at the solid-fluid transition under amplitude test sweep.Storage and loss modulus in the linear viscoelastic range and yield stress have an exponential growth relationship with sediment concentration.In addition,a stress constitutive relation and a new exponential law describing the evolution of yield stress required for solid-liquid transformation were proposed,and the relationship is further strengthened through a comprehensive analysis of existing results,which expands the evaluation application of the rheological characteristics of tailings flow.This paper provides a new insight into the rheological properties of tailing and how they occur through solid-liquid transition under different environments,which is beneficial to geological hazard prevention and the ecological remediation of the mining area.

The Research for Surface Properties of Steel Slag Powder and High-Temperature Rheological Properties of Asphalt Mortar

In order to evaluate the feasibility of steel slag powder as filler,the coating properties of steel slag and limestone aggregate were compared by water boiling test,the micro morphology difierences between steel slag powder and mineral powder(limestone powder)were compared by scanning electron microscope(SEM),and the high-temperature rheological properties of asphalt mortar with difierent ratio of filler quality to asphalt quality(F/A)and difierent substitution rates of mineral powder(S/F)were studied by dynamic shear rheological test.The results show that the surface microstructure of steel slag powder is more abundant than that of mineral powder,and the adhesion of steel slag to asphalt is better than that of limestone.At the same temperature,the lower the ratio of S/F is,the greater the rutting factor and complex modulus will be.In addition,the complex modulus and rutting factor of the asphalt mortar increase with the increase of F/A,and the filler type and F/A have a negligible efiect on the phase angle.

Rheological and physicomechanical properties of rod milling sand-based cemented paste backfill modified by sulfonated naphthalene formaldehyde condensate

Rod milling sand(RMS)—a coarse sand aggregate—was recycled for cemented paste backfill(CPB)for the underground mined area at the Jinchuan nickel deposit,named rod milling sand-based cemented paste backfill(RCPB).The adverse effects of coarse particles on the transportation of CPB slurry through pipelines to underground stopes resulting in weakening of the stability of the backfill system are well known.Therefore,sulfonated naphthalene formaldehyde(SNF)condensate was used for the performance improvement of RCPB.The synergistic effect of solid content(SC),lime-to-sand ratio,and SNF dosage on the rheological and physicomechanical properties,including slump,yield stress,bleeding rate,uniaxial compressive strength(UCS),as well as mechanism analysis of RCPB,have been explored.The results indicate that the effect of SNF on RCPB performance is related to the SNF dosage,lime-to-sand ratio,and SC.The slump of fresh RCPB with 0.1wt%-0.5wt%SNF increased by 2.6%-26.2%,whereas the yield stress reduced by 4.1%-50.3%,indicating better workability and improved cohesiveness of the mix.The bleeding rate of fresh RCPB decreased first and then rose with the increase of SNF dosage,and the peak decrease was 67.67%.UCS of RCPB first increased and then decreased with the increase of SNF dosage.At the optimal SNF addition ratio of 0.3wt%,the UCS of RCPB curing for 7,14 and,28 d ages increased by 31.5%,28.4%,and 29.5%,respectively.The beneficial effects of SNF in enhancing the early UCS of RCPB have been corroborated.However,the later UCS increases at a slower rate.The research findings may guide the design and preparation of RCPB with adequate performance for practical applications.

Effect of Synthetic Conditions and Thickener Formulation on the Rheological and Tribological Properties of Polypropylene Grease

Polypropylene(PP)grease holds great potential for special industrial applications.In this study,synthetic conditions,thickener content,and the ratio of two different molecular weight PPs were investigated systematically using a rheometer,scanning electron microscope,X-ray diffraction,Fourier transform infrared spectrometer,oscillating tribometer,and 3D surface profiler measurements.The results showed that suitable synthetic conditions are two quenching cycles,and the synthetic temperature and time is 240℃for 12 h.The rheological analysis showed that thickener content and different proportions of the two PP molecular weights have a significant influence on the rheological properties of PP grease.High molecular weight PP(H-PP)has a stronger thickening ability than low molecular weight PP(L-PP).The higher the amount of H-PP in the fixed thickener content or the higher the thickener content with a specific proportion,the higher the viscoelasticity of PP grease.The tribological performance is related to the rheological properties.The proportion of two different molecular weight PPs in the thickener content should be appropriate;excessive H-PP content leads to lubrication failure.

A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods:antioxidant and bile acid-binding capacity

In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

Rheological properties of polymer micro-gel dispersions

The influence of swelling time, temperature, NaCl concentration and polymer micro-gel concentration on rheological properties of polymer micro-gel dispersions was studied by using a HAAKE rheometer. The results showed that with increasing swelling time and NaCl concentration, the polymer micro-gel dispersions changed from a shear-thickening fluid to a Newtonian fluid. The polymer micro-gel dispersion show shear-thinning in non-saline water. At higher swelling temperature, the time of the polymer micro-gel dispersion showing shear-thickening was shorter. With increasing polymer micro-gel concentration, the dispersion changed from shear-thickening to shear-thinning.

Investigation of regulating rheological properties of water-based drilling fluids by ultrasound

Regulating rheological properties of water-based drilling fluids has always been a hot topic.This paper proposed a new method for regulating rheological properties of water-based drilling fluids by ultrasonic field.The experimental results showed that the ultrasound increased the viscosity and yield point of bentonite suspension by reducing the particle size of clay,destroying the network structure between clay particles,increasing the mud yield and the cation exchange capacity of bentonite,and promoting the hydration dispersion of bentonite.The change of rheological property showed a memory effect at room temperature and high temperature.Besides,the ultrasonic energy affected the network structure between clays and polymer chains,thus regulating the rheological properties of the bentonite-polymer system.For two types of drilling fluids investigated,the rheology of the poly-sulfonate drilling fluid was regulated by damaging the grid structure between additives and clays by low-power ultrasound and reducing the clay particle size by high-power ultrasound,while the rheology of the deep-water drilling fluid was mainly regulated by disentangling the spatial grid structure between additives.Additionally,ultrasound showed no effect on the lubricity,inhibition and stability of drilling fluids,which proved the feasibility of ultrasound to regulate rheological properties of water-based drilling fluids.

Thickening and Rheological Properties of Crystalline Polyester Used in Low Pressure Sheet Molding Compounds

Low pressure sheet molding compound （LPMC,1.0-3.0 MPa,95-103 ℃） is a new kind of thermosetting material with crystalline polyester as a physical thickenner.LPMC is different from conventional SMC using an earth oxide thickening agent （e.g.MgO） as chemical thickenner,it relies on the physical thickening of crystalline polyester.Crystalline polyester resin is the key material to mold LPMC parts.Currently there was no report about the thickening mechanism of crystalline polyester in LPMC.In this article,crystalline polyester resins,whose melting points were between 45 ℃ and 89 ℃,were synthesized by a two-step esterification.The melt points of crystalline polyesters are controlled by regulating the mol ratio of the two glycols and the two acids.And by means of varying the content of crystalline polyester resin,the thickening effect on resin paste is investigated.In addition,the thickening mechanism of crystalline polyester in LPMC was investigated by FTIR and DSC analysis.The effects of the diameters and viscosity of crystalline polyester on the rheological property and fiber distribution of LPMC sheets were studied,too.Results show that the thickening effect is excellent when the weight content of crystalline polyester resin is 3%.And there exists three kinds of functions acting in the process of thickening：swelling,hydrogen bonds and induction crystallization.During the preparing process of resin paste in LPMC,the temperature of resin paste must be kept at 90 ℃.In addition,crystalline polyester make LPMC have a perfect fluid property.When the viscosity of LPMC sheet is beyond 1 kPa s,the fiber orientation is not obvious.But when the viscosity of LPMC sheet is about 500 Pa s,the fiber shows a certain degree of orientation.Moreover the study of physical and chemical thickening mechanism of crystalline polyester and the rheological discipline of LPMC sheets in the hot mould will provide the researchers and enterprises with theory guidance.

THE RHEOLOGICAL PROPERTIES OF POLYANILINE SOLUTION

This paper presents our work on the rheological properties of the solution of polyaniline (PAn) in N-methyl-2-pyrrolidone (NMP). The results indicate that the solution's non-Newtonian property becomes more prominent with the increase in solution concentrations exhibiting the behavior of pseudo-plastic fluid. Besides, there is a critical concentration C-v (around 0.06 g/ml), beyond which the viscosity of the PAn/NMP solution takes a sudden increase. with temperature rising, both the viscosity and the thixotropy of the solution decrease, implying that there exist physical cross-linking interactions between the molecular chains in the solution.

Comparison of the rheological properties of four root canal sealers

The flowability of a root canal sealer is clinically important because it improves the penetration of the sealer into the complex root canal system. The purpose of this study was to compare the flowabilities of four root canal sealers, measured using the simple press method （ISO 6876）, and their viscosities, measured using a strain-controlled rheometer. A newly developed, calcium phosphate-based root canal sealer （Capseal） and three commercial root canal sealers （AH Plus, Sealapex and Pulp Canal Sealer EWT） were used in this study. The flowabilities of the four root canal sealers were measured using the simple press method （n= 5） and their viscosities were measured using a strain-controlled rheometer （n=5）. The correlation between these two values was statistically analysed using Spearman＇s correlation test. The flow diameters and the viscosities of the root canal sealers were strongly negatively correlated （p= -0.8618）. The viscosity of Pulp Canal Sealer EWT was the lowest and increased in the following order： AH Plus〈Sealapex〈Capseal （P〈0.05）. All of the tested root canal sealers showed characteristic time- and temperature-dependent changes in their rheological properties. The viscosities measured using the strain-controlled rheometer were more precise than the flowabilities measured using the simple press method, suggesting that the rheometer can accurately measure the rheological properties of root canal sealers.

Rheological and Adhesive Behavior of Gunning Mix for Blast Furnace Repair

The aim of this experimental work was to investigate the Theological and adhesive performance of gunning mix suspensions. The results of rheological tests indicate that: the rheological curve of gunning mix bonded by high-alumina cement (HACG) is Bingham type ; the rheological curve of low cement gunning mix (LCG) bonded by mi-crosilica is characterized by pseudo-plasticity fluid with yielding stress ; and the rheological property of low-cement gunning mix bonded by microsilica is proved to be better than that of gunning mix bonded by cement. Meanwhile as indicated by the adhesive tests: the better the rheological properties of gunning mix suspension , the better the repair effect would be.

Study and Formulation of Composite Flours Based on Gluten Flour and Local Cereal Flours: Fonio, Millet and Sorghum

This study makes it possible to establish baking flours of nutritional quality and technologically acceptable following the increase in their rheological parameters due to the insertion of gluten flour. The composite flours were obtained using the Philips mixer type (model HR2811). The nutritional qualities of the formulated flours were determined by the Kjeldahl, AOAC 985-29, UV-VIS spectrophotometry (DR 5000;HACH and LANGE, France) and Soxhlet gravimetric methods. The compounds obtained are respectively: Protein, carbohydrate, lipid, micronutrient and vitamin contents. Monitoring the analysis of functional properties (water and oil absorption capacity) as well as baking value.

Studies on Rheological Properties of Konjac-tea Drink

Konjac black tea(sugar-free) and konjac glucomannan(KGM) solution were studied by using rheometer,refractometer etc.The relationship between their rheological properties and temperature or concentration was discussed in detail.The results showed that viscosity was significantly affected by temperature and concentration;and pH stability of Konjac-tea was related to the molecular property of KGM.

RESEARCH ON THE RHEOLOGY OF MAGNESIUM OXYCHLORIDE CEMENT Ⅰ—RHEOLOGICAL BEHAVIOR

The rheology of magnesium oxychloride cement (MOC) was presented. The rheological properties and thixotropic behaviors of the MOC pastes were determined with a rotating viscometer. The results have showed significant difference between the MOC and portland cement in terms of their rheological behaviors. The yield stress and plastic viscosity of the MOC pastes are much larger than those of portland cement pastes. Therefore, the MOC has a better cohesive property.

Rheological and Sintering Properties of Two Kinds of Corundum-spinel Micropowders

For the proper use of micropowders in castables,slurries and fired samples were prepared with two kinds of corundumspinel micropowders(D and G).The effects of the solid content and disperser WSM-R1 on the rheological properties of the slurries were studied.The sintering properties and the slag corrosion resistance of the fired samples were also researched.The results show that:the slurries all show pseudoplastic rheological characteristics.With the same solid content,the slurry with micropowder G has higher initial viscosity than that with micropowder D.Disperser WSM-R1 significantly reduces the initial viscosity of the two slurries and plays a more obvious dispersing effect on the slurry with micropowder G.The fired sample with micropowder G has higher bulk density,lower apparent porosity and better corrosion resistance than that with micropowder D.