Korea-Australia Rheology Journal最新文献

We prepared carbon fiber (CF) reinforced polycarbonates (CFR-PC) by co-rotating twin screw extruder and injection molding. We simulated the orientational morphology of CFR-PC by inverse calculation from the measured transient stress curve using 8 mm disk rotational rheometer. The shear stress evolution was expressed by a function of the Fredholm integral of the first kind; total stress was expressed by a linear combination contributed from a stress at each orientation state. We employed an extended White–Metzner model with Dinh–Armstrong flow-fiber coupling term as a constitutive equation for the evaluation of stress at each orientation state. The probability density of each orientation state was determined by the Tikhonov regularization method from the measured stress overshoot. Finally, the orientation distribution functions (ODFs) of CFR-PC were determined by maximum entropy method from the determined probability density of orientation state. For the CFR-PCs, the simulated morphology by the ODF was well consistent with the morphology obtained by optical microscopy.

Large MR (MR) dampers are popular due to their higher damping force capabilities which makes them suitable in the field of civil engineering, structural engineering, suspension bridge structure, mining engineering, and agricultural engineering applications. This paper presents a comprehensive review of large MR dampers. The classifications and applications of large MR dampers, the principle of operation, different fluid models, their structural design and control systems are classified and reviewed in this paper. The large MR dampers have higher damping force controllability than conventional MR dampers. The review indicates that the large MR dampers have enough vibration mitigation ability and higher damping performances.

The energy demand for crude oil (CO) has increased globally which encourages the growth in the petroleum industry worldwide. When CO is transported through a pipeline over long distances, due to the change in environmental circumstances, the flow behavior of CO also changes. To improve the flowability of CO through the pipeline, a better understanding of the rheological behavior of CO is very important. In this paper, several experiments were conducted to improve the flowability of CO through pipeline transportation. Dilution of CO with its products like Superior Kerosene Oil (SKO) was selected as it improves the CO flowability through the pipeline and is economically affordable. In this study, the effect of SKO on ^oAPI gravity, Pour Point, Gel Point, Viscosity Gravity Constant, and rheological parameters were studied for the CO of Upper Assam Basin, Assam. SKO was mixed with CO in different ratios to examine the effect of SKO on it. The results obtained showed that with the addition of SKO, ^oAPI increases, the minimum limit of attaining paraffinic nature of CO samples can be determined, heavier CO may not always have high Pour Point and Gel Point. The variation in yield stress of CO with SKO was also observed. Hershel-Buckley Model (HBM) was used and from the three parameters of HBM, the shear-thinning or shear thickening behavior of CO was determined. Therefore, this paper attempts to study the flow behavior of CO and also to identify the % of SKO required for improving their flowability through the pipeline.

Ternary colloidal or “capillary” suspensions comprising bulk and secondary fluids (S) and particles have attracted considerable attention in recent years. The addition of a suitable S can readily initiate the transition of a fluid-like pre-mixture into a gel-like capillary suspension. However, the precise control of rheological properties of such suspensions in the gel state is still challenging. In this study, we investigated the effects of the addition of various water-soluble polymers in an aqueous S on the rheological properties of the capillary suspensions. Results suggest that all the investigated systems maintained the gel state. Cellulose-type polymers with high molecular weights increased the sample strength, which was attributed to the gelation and reduced rupture of interparticle capillary bridges. In contrast, the non-cellulose-type polymers decreased the sample strength, which may be attributed to the interparticle repulsion and/or decrease in the capillary force. We believe this study will aid the design of various industrial complex fluids that often contain multiple immiscible fluids and polymeric additives.

The quality of the products manufactured by injection molding is greatly influenced by the process variables of the injection molding machine used during manufacturing. It is very difficult to determine the process variables considering the stochastic nature of the manufacturing process, because the process variable complexly affects the quality of the injection molded product. In the present study, we used an artificial neural network (ANN)-based method to determine injection molding process variables to manufacture products of desired quality, as ANNs are known to be highly accurate in analyzing non-linear problems. To train the ANN model, a systematic plan was developed using a combination of orthogonal and random sampling methods to represent various and robust patterns with a small number of experiments. According to the plan, injection molding experiments were performed to generate data, which were separated into training, validation, and test sets to optimize the ANN model parameters and test its predicting performance. Multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) models were developed to predict 8 process variables to manufacture a product with specific dimensions and provide user reference information (mass and pressure at the end of fill). The predicted process variables were applied to an injection molding machine to verify the predicted accuracy of the ANN system. Finally, it was confirmed that the determination of process variables using the ANN method meets the tolerances required in general industry practice.

Magnetorheological (MR) properties of the carbon nanotube (CNT)–FeCo nanocomposite particle suspension were investigated to find a high-performance MR fluid with great stability. The composites were fabricated by chemical deposition of FeCo on the surface of amine functionalized CNTs. The strong magnetic polarization of the FeCo moiety led to strong MR performance of the nanocomposite particle suspension. The MR fluid exhibits high yield stress value, 4 times greater than that of the suspension including Fe₃O₄-deposited CNT at a magnetic field strength of 86 kA/m. A three-dimensional network-like structure formed by the non-magnetic CNTs in the MR suspension does not contribute to the additional yield stress. The low density and the surface roughness of the CNTs resulted in far better long-term stability for the CNT–FeCo nanocomposite suspension than for the MR suspension of hierarchically structured Fe₃O₄ suspension with a similar density. The effect of the three-dimensional network-like structures by the CNTs on the MR performance depends upon the interaction strength between the magnetic moiety on the CNTs.

Pickering emulsion, which is stabilized by colloidal particles, has shown great promise in various fields due to its great stability and processibility. Depending on the type, size, number of colloidal particles, volume fraction of the dispersed phase, and emulsification method, various Pickering emulsions with different internal structures can easily be produced. Furthermore, according to the internal structure, the considerably different rheological properties can be achieved, from Newtonian viscous-like response to Hookean solid-like response. This strongly suggests that the rheological properties of Pickering emulsions can be tuned, especially for specific applications. In this paper, we summarize the progress in the measurement and understanding of the rheological properties of Pickering emulsions. We also categorize them into three different sections, depending on the volume fraction of the dispersed phase. Furthermore, we introduce the applications of Pickering emulsions that have recently become popular due to their distinctive rheological properties.

The present paper sheds some light on the problem of dispersal of a solute in electro-magneto-hydrodynamic peristaltic flow of Jeffrey fluid in a uniform channel filled with porous medium and compliant walls. Using long wavelength approximation and Taylor’s limiting condition, the homogeneous and heterogeneous chemical reaction have been analysed. The effects of physiological parameters such as the electro osmotic velocity, electro kinetic, Jeffrey fluid parameter, Hartmann number, Darcy measure, velocity slip parameter and the wall complaint parameters on the Peristaltic movement have also been investigated. The numerical results have been computed and visibly discussed with respect to assorted values of pertinent physical parameters. It pointed out first time, that the average equivalent dispersion coefficient (dispersion of a solute) is significantly reduced due to increase in the electro osmotic velocity and electro-kinetic parameter. Further, the chemical reaction parameters and Hartmann number slow down the dispersion mechanism but Darcy number, velocity slip parameter and amplitude ratio parameters tend to increase the average equivalent dispersion coefficient. Another notable result is that the damping parameter of the wall (left( {E_{2} } right)) and wall mass characteristic parameter (left( {E_{1} } right)) increase the dispersion nature of the solute whereas it is reduced by increasing the rigidity nature of the wall (left( {E_{3} } right)), the spring stiffness parameter of the wall ((E_{5})) and the wall tension ((E_{4})). Further, dispersion nature on different waveforms in the peristaltic transport has been studied. The present analytical study provides useful information to artificial bio-processors.

In this study, the properties of whey-less Feta cheese (WLFC) manufactured from milk protein concentrate (MPC) with the addition of soy protein isolate (SPI) were investigated. Six treatments were made using different ratios of MPC:SPI (12:0, 10:2, 9:3, 8:4, 7:5, 6:6% w/v) and stored for 45 days. Then, the textural properties, rheological behavior of samples, and microstructural and sensory features were evaluated. Furthermore, FTIR spectroscopy was used to provide spectral data on the protein, acids, carbohydrates, lipids, and water. The results showed that different concentrations of SPI significantly affected pH, acidity, total solids (TS), and color parameters. So that, by increasing SPI concentration, the lightness and greenness decreased, and the yellowness increased. The viscoelastic behavior of all samples demonstrated a higher G′ compared to G″. The replacement of MPC with SPI decreased G′, G″, and texture parameters. The images of the microstructure indicated a weak structure with a more open protein network in WLFCs fortified with high levels of SPI (5, 6%). In conclusion, results showed that SPI could be a good substitution for MPC at a 2–3% concentration without negative effects on WLFCs.