• International Journal of Concrete Structures and Materials
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• v.10 no.sup3
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• pp.75-85
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• 2016

Large scale constructions needs to estimate a possibility for pumping concrete. In this paper, the state of the art on prediction of concrete pumping including analytical and experimental works is presented. The existing methods to measure the rheological properties of slip layer (or called lubricating layer) are first introduced. Second, based on the rheological properties of slip layer and parent concrete, models to predict concrete pumping (flow rate, pumping pressure, and pumpable distance) are explained. Third, influencing factors on concrete pumping are discussed with the test results of various concrete mixes. Finally, future need for research on concrete pumping is suggested.

• Korea-Australia Rheology Journal
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• v.11 no.3
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• pp.169-195
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• 1999

An electrorheological fluid (ERF) is typically a suspension of semi-conducting solid particles dispersed in an insulating carrier fluid, and shows a dramatic change in rheological properties when an external electric field is applied. This rapid and reversible change in flow properties has potential application in many electronically controlled mechanical devices, but the development of efficient devices and optimal materials for ERF is still hindered by incomplete understanding of the fundamental physical mechanisms involved. In recent years there have been considerable advances In relating microstructural models to the rheological behaviour, and these will form the basis of this review. Results of the theoretical calculations and simulations will be compared to the key experimental evidence available. An overview of the fundamental physical concepts behind electrorheological fluid behaviour will also be presented.

• Korea-Australia Rheology Journal
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• v.12 no.3_4
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• pp.175-179
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• 2000

Rheological properties of chitosan solutions were investigated as a function of polymer concentration. The viscosity curves for chitosan solutions consisted of two distinct viscosity regions, the Newtonian zero-shear viscosity (η$_{0}$) region and the shear rate dependent apparent viscosity (η$_{app}$) region. The shear rate dependence of viscosity was more clearly observed at higher chitosan concentrations. The critical coil overlap parameter (C＊〔η〕) was determined to be approximately 3.2 from a plot of zero-shear specific viscosity η$_{sp,0}$ vs coil overlap parameter (C〔η〕), which was lower than C〔η〕4.0 reported for other random coil polysaccharides. It was also found that the slope of η$_{sp,0}$ vs C〔η〕 was 3.9 at concentrated C〔η〕>C＊〔η〕domain, while 1.2 at dilute C〔η〕$_{0}$ ${\gamma}$/${\gamma}$$_{0.8}$ relation.ion.n.n.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.464-467
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• 2002

This paper presents investigation of damping characteristics of squeeze mode type MR (magneto-Rheological) mount experimentally. Since damping property of the MR fluid is changed by variation of the applied magnetic field strength, squeeze mode type MR mount proposed in the study has variable damping characteristics according to the applied magnetic field strength. Impact and excitation tests were performed to investigate the dynamic properties of squeeze mode type MR mount. Responses of the mount were compared in proportion to the applied magnetic field strength. The experimental results show that the mount can effectively reduce vibration amplitude in a wide frequency range by changing the applied magnetic field strength.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.1013-1018
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• 2009

Several rheological terms were introduced to estimate the properties of cooked noodles with different starch content using tensile tests. Ring-shaped specimens were prepared by connecting both ends of the noodle strip before cooking. Hencky strain and rate, as well as true stress were applied in constant deformation tests. The elastic region on the curves of strain vs. stress was not clearly identified. Strain hardening in the subsequent plastic region was more prominent in low-starch noodles. Elongational viscosities at lower strain rates were used to differentiate noodles with different starch content, representing the dominant effect of protein content in the range of lower strain rates. In stress relaxation tests, the reciprocal of Peleg's constant $K_1$ (initial decay rate) and $K_2$ (asymptotic level) increased and decreased respectively, with an increase in starch content. This indicated that addition of starch contributed to the noodles becoming viscous liquid rather than elastic solid.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.1027-1029
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• 2009

The aim of this research was to study the structural and rheological properties of gels formed by ferulated maize bran arabinoxylans (MBAX) at different concentrations. MBAX was cross-linked by a laccase leading to the formation of dimers and trimers of ferulic acid (di-FA, tri-FA) as covalent cross-link. An increase in MBAX gels elasticity (from 11 to 20 Pa) as well as lower mesh size (from 80 to 48 nm) were obtained by augmenting the MBAX concentration from 2.5 to 3.5%(w/v), respectively, but no increase in di-FA and tri-FA content was obtained (0.03 and 0.014 ${\mu}$g/mg MBAX, respectively).

• Advances in concrete construction
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• v.5 no.3
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• pp.183-199
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• 2017

This paper reports an experimental study into the rheological behaviour of Smart Dynamic Concrete (SDC). The investigation is aimed at quantifying the effect of the varying amount of mineral admixtures on the rheology, setting time and compressive strength of SDC containing natural sand and crushed sand. Ordinary Portland cement (OPC) in conjunction with the mineral admixtures was used in different replacement ratio keeping the mix paste volume (35%) and water binder ratio (0.4) constant at controlled laboratory atmospheric temperature ($33^{\circ}C$ to $35^{\circ}C$). The results show that the properties and amount of fine aggregate have a strong influence on the admixture demand for similar initial workability, i.e., flow. The large amounts of fines and lower value of fineness modulus (FM) of natural sand primarily increases the yield stress of the SDC. The mineral admixtures at various replacement ratios strongly contribute to the yield stress and plastic viscosity of SDC due to inter particle friction and cohesion.

• Journal of Pharmaceutical Investigation
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• v.5 no.3
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• pp.43-49
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• 1975

The rheological properties of seven mixed sugar solutions of glucose, fructose, maltose, sucrose, and two kinds of honey, the chestnut and the acacia, were discussed. The fluidity of the above samples were studied by using the applied pressure horizontal viscometer with which glycerine was confirmed to be a Newtonian flow at $25^{\circ}C$. Time required to pass the constant volume of the sample fluids through the capillary was measured at various pressure differences, ${\Delta}p$, and the ${\Delta}p$ vs ${\Delta}p{\cdot}t$ in the Poiseuille equation was plotted. Shear rate against shearing stress, on the other hand, was plotted for the sample fluids and it was found that all the sample fluids have shown a Newtonian behavior. It was interesting to note that the shear viscosity increased as the concentration of sugar solutions increased, and as the concentration of sucrose became higher than that of maltose, although the total concentration of sugar solution is constant.

• Journal of Microbiology and Biotechnology
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• v.3 no.3
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• pp.209-213
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• 1993

The flow behavior of the mycelial broth of glucoamylase hyperproducer Asp. niger No. PFST-38 for the production of glucoamylase were studied. The mycelial broth followed Bingham-pseudoplastic flow model described by Herschel-Bulkley equation. The yield stress increased with the increase in mycelial concentration. The dependency of the consistency index and the flow behavior index on the mycelial concentration could be expressed by a linear relationship. The consistency index increased proportionally with the mycelial concentration while the flow behavior index decreased with the increase in mycelial concentration. The flow property of the broth was related to the morphological data obtain in the previous study. The changes in apparent viscosity of the broth could be expressed as a function of the hyphal thickness as shown below.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.133-134
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• 2006

In contrast to paints, the surface appearance of adhesive materials is of minor importance, because the adhesive is invisible between the two substrates. Therefore, the rheological properties needed to apply an adhesive dispersion by spray coating can be quite different. The influence of three different kinds of thickeners on the spraying behaviour of polyurethane adhesive dispersions was investigated. The associative thickener showed only minor changes, whereas the higher molecular weight soluble thickeners dramatically changed the spraying angle and the amount of overspray. Determination of the elongational viscosity by means of the CaBER rheometer proved to be of limited use for thickened dispersions.