Papers by Keyword: Rheological Characteristic

Abstract: The cemented coal gangue-fly ash backfill (CGFB) slurry has commonly been used to control subsidence damage caused by underground coal mining. This paper discusses the CGFB slurry rheological characteristic associated with the various percentage of the fly ash within the configuration of the mixture. A general description about CGFB slurry fluidity in the pipe transportation is provided. The physical, chemical and rheological characteristic of the CGFB have been determined in the test. The fly ash was mixed with 18%, 20% and 22% of solid concentration with respects to 12%, 10% and 8% for cement on various concentrated CGFB slurry ranges 76.05%, 78.05% and 80.05%. The tests verify the CGFB slurry exhibits non-Newtonian behavior in nature as Bingham plastic fluid. The experimental data show CGFB slurry rheological characteristic is noticeable influenced by the slurry solid concentration and the proportion of the fly ash, which affects the value of yield stress and viscosity. The lower value of the rheological parameters was observed on 22 % fly ash other than the 18 % case based on the same solid concentration of CGFB slurry.

Abstract: Mixing homogeneity and the feedstock rheological characteristic for optimal binder formulation in metal injection moulding is evaluated between Polypropylene (PP) and Sewage fat (SF) or Fat Oil Grease (FOG). Difference powder loading of SS316L also being used here to determine the possibility of the best binder formulation selected could be optimised for optimal powder loading base on rheological characteristic analysis. Two binder formulations of PP to SF being selected here are 60/40 and 70/30 accordingly with the powder loading of 60% and 55% for each binder formulation. The analysis will be base on viscosity, shear rate, temperature, activation energy, flow behaviour index and moldability index. It is found that rheological result shows all the two binder formulations with both powder loading exhibit pseudoplastic behaviour or shear thinning where the viscosity decrease with increasing shear rate. Feedstock viscosity also decrease with increasing temperature indication of suitability for moulding. Results from all the analysis conducted shows that the volumetric powder loading of 60% with binder volumetric of 60% for PP and 40% for SF contributes significant stability and suitability for optimum powder loading.

Abstract: This paper improves the existing pressure pipe rheological and resistance characteristic test system and optimizes the pressure and flow data acquisition method. Taking coal slime as an example, it conducts an experimental study on dense paste's rheological characteristics. It ensures the coal slime's rheological model transported in different pipe diameter of which the volume concentration is 57.06%～45.44%and analyses the rheological characteristic trend changing with diameter and volume concentration. The experiment proves that the new system is practicable and easy-operated and reliable. Also the original experimental data and processed result are in accordance with theoretical regulation.

Abstract: 1-Butyl-3-methylimidazolium chloride ([BMIM]Cl) was applied as solvent to dissolve the cellulose diacetate (CDA) directly. The solution rheology of CDA in [BMIM]Cl was investigated by steady shear and oscillatory shear measurements. In the range of the concentration and temperature studied, CDA/[BMIM]Cl solutions showed the typical shear-shinning behavior and the viscosity decreases with increasing temperature. Compared with the cellulose solutions in [BMIM]Cl, the smaller apparent viscosity of CDA/[BMIM]Cl was shown, which mainly resulted from the weakened interaction between substituted cellulose chains and ionic liquid. The deviation of Cox–Merz rule with steady shear viscosity smaller than complex viscosity in the whole deformation rate range we studied indicates that entangled CDA/[BMIM]Cl solutions are not homogeneous solution systems.

Abstract: This paper investigates the performance of feedstock characteristics for micro metal injection molding (μMIM) by using optimum power loading variation and rheological characterization. The study has been emphasized on the powder and binder system in which stainless steel SS316L powder are mixed with composite binder, which consists of PEG (Polyethelena Glycol), PMMA (Polymethyl Methacrilate) and SA (Stearic Acid) by variation of powder loading concentration. The rheology properties are investigated using Shimadzu Flowtester CFT-500D capillary rheometer. As the geometry of water atomised stainless steel powder are irregular shape, therefore it is expected significant changes in the rheological results that can influence the microcomponent, surface quality, shape retention and resolution capabilities. The optimization of the μMIM rheological properties as a function of stainless steel powder loading concentration are evaluated by flow behavior exponent, activation energy and moldability index. From the results, it shows that 61.5%vol contributes a significant stability over a range of temperature and the best powder loading from a critical powder volume percentage (CPVP) and rheological point of view.

Abstract: The effect of short-term aging on rheological properties of asphalts was studied. In this paper, asphalt was aged by rolling thin film oven, which was carried out for 300 minutes and were analyzed at an interval of 75 minutes. The paper gives a description of the most commonly used conventional tests, such as Penetration and Softening Point, and a more detailed description of the viscoelastic behavior and dynamic testing of asphalts by way of Brookfield viscometer and Dynamic Shear Rheometer (DSR). It is found that there are a decrease in penetration and an increase in softening point with aging. The viscosity of aged asphalts was observed to increase with time. The DSR results show that short-term aging significantly increases the complex modulus at low temperature, but complex modulus at high temperature was just lightly affected. The four tests results were also incorporated to evaluate the temperature susceptibility and the rheological characteristics of asphalt binders.

Abstract: The aim of this research is to improve characteristic of magnetorheological fluid, and to supply theoretic basis for preparing MRF and applying MRF. By molecular dynamical simulation in MATLAB, microstructure of MRF, mechanism of MRF, and factors of affecting MRF characteristic were investigated. Based on theory of magnetic dipoles and microstructure characteristic of MRF, various factors affecting magnetic chain structure were considered, microcosmic model of MRF was established, factors affecting velocity of MRF forming chains were analyzed.

Abstract: The rheological properties of brucite fiber asphalt mastics are studied by the Brookfield viscosity test in this paper. The results show that at 105°C and 120°C, brucite fiber asphalt mastics shows the characteristics of non-Newtonian fluid. At 135°C and 150°C, it shows the characteristics of Newtonian fluid gradually. When the temperature is higher than 150°C, the asphalt mastics has fully manifested the characteristics of Newtonian fluid. The viscosity increases with the increasing of the dosage of brucite fiber. The value of ZSV increases with the increasing of the dosage of brucite fiber. According to the change law of ZSV, the anti-rutting performance of asphalt mastics is improved by the addition of brucite fiber.

Abstract: The mixture of asphalt and filler called asphalt binder is an adhesive and packing material in asphalt mixture. In this paper, the influence of different filler sorts such as limestone dust and hydrated lime, and different rates of limestone dust and hydrated lime such as 2:1, 1:1 and 1:2 at the same mass ratio of filler/asphalt (1.0) on the asphalt binder’s properties has been studied. The paper gives a description of the most commonly used conventional tests, such as Penetration and Softening Point, and a more detailed description of the viscoelastic behavior and dynamic testing of bitumen by way of Brookfield viscometer and Dynamic Shear Rheometer (DSR). The contrasts among different test results were presented. It is found that there are a decrease in penetration and an increase in softening point with increasing hydrated lime content. The viscosity also increases obviously with the mass of hydrated lime increases. The DSR results show that hydrated lime can increase asphalt binders' anti-shear stress and G*/sinδ, and are helpful to its properties at high temperature. The four tests results were also incorporated to evaluate the temperature susceptibility and the rheological characteristics of asphalt binders.

Abstract: In order to improve the sweep efficiency of water flooding in matured oilfield, soft moveable gels (SMG) are developed. The new types of SMG are made of novel, expandable particulate materials. The gels are preformed, stable, size controlled, non-toxic and can reduce water permeability without affecting oil permeability significantly. In this paper, some relevant laboratory methods are carried out for the determination of their main characteristics, including the displacement mechanism, the physio-chemical properties, moblility in porous media and the adjustment of permeability. Furthermore, the properties in bottles and behavior in porous media have also been investigated. The results shows that: 1)the swelling times of SMG are approximately 10, 2)SMG can remarkably improve the efficiency of water flooding, 3)remaining oil startup in low permeability formation, multistage fluid diverting and deep profile control are the main oil displacement mechanisms, 4）the new promising gel system of SMG have extensive application prospects in deep water shutoff and conformance control.