Effects Of Suspension Properties Research Articles

Effects of suspension properties on the microstructure of Al2O3 coatings deposited onto macroporous SiC substrate

In this paper the effects of the suspension preparation conditions on suspension coating of porous substrates were investigated. Alumina suspensions were prepared using varying types of additives, including non-ionic polyethylene glycol (PEG), cationic polyethylene imine (PEI), and anionic sodium carboxymethyl cellulose (CMC). Prepared suspensions were coated on porous SiC substrates by spin coating. The flow curves of the suspensions were measured, whereas their particle dispersion states were also observed directly using an optical microscope. In addition, the surface and cross-section of each coating were observed by SEM and analysed by EDX. Finally, the air permeability of each coating was measured.For the suspension with PEG, alumina particles dispersed well in the suspension and the added PEG formed a network structure, resulting in a homogeneous coating on the surface of the substrate with less particle penetration into the substrate pores. For the suspension with CMC and the suspension with PEI, since particles flocculated in the suspensions, particle penetration into the substrate pores hardly occurred, however, the formed coating was inhomogeneous.

A comparison of microfiltration and inertia-based microfluidics for large scale suspension separation

Abstract Separation of suspensions can be carried out by microfiltration and microfluidic techniques, although both rely on different principles. Conventional microfiltration involves retention of particles by a porous membrane, but is limited by (irreversible) particle accumulation and concentration polarization that can only be (partially) controlled by back pulsing that transfers particles back into the bulk. Microfluidic separation devices employ a combination of inertial forces and sometimes geometric constraints to control particle migration behaviour, which allows splitting of suspensions into concentrated and diluted streams. Considering their effectiveness, inertia-based microfluidic separation is regarded an interesting alternative to microfiltration; therefore, this paper focusses on the use of inertial forces in suspension separation. This resulted in the selection of three concepts, which were: (1) fluid skimming, which is a combination of microfiltration and controlled particle migration behaviour, (2) spiral inertial microchannel separation, in which particles migrate fast towards an equilibrium position, and (3) sparse deterministic ratchets, which use geometric interactions to induce particle migration. In a concluding section, the application of controlled migration behaviour in relation to scalability of inertia-based microfluidic separation techniques and the effect of suspension properties on separation are discussed in detail.

The Effects of Ore Properties on the Characterization of Suspension in Settling and Compression

Many studies have considered the effects of suspension properties on the dewatering process but fewhave focused on ore properties. Thus, the present work studied the effects of ore properties (density,particle size, mineralogy) on the dewatering process based on lab and pilot experiments. A hydrocyclonewas used to prepare the required samples for the experiments. To study the effects of mineralogicalproperties, the sedimentation behaviour of hydrocyclone feed and underflow samples were compared. Itwas observed that the free-settling velocity of feed (2 to 6mm/sec) was less than in the underflow sample(2 to 7mm/sec) and the final concentration of underflow sample (0.45 to 0.48t/m3) was more than thefeed sample (0.44 to 0.47t/m3). Additionally, to study the effects of particle size and density, thesedimentation behaviour of hydrocyclone overflow and feed samples were compared. The settlingvelocity and final concentration of overflow sample were obtained at 0.15 to 0.4mm/sec and 0.32t/m3,respectively, which was significantly less than the feed sample. This was due to the amount of clayreduction in the underflow sample and particle size and density reduction in the overflow sample.Following on, the pilot experiments were carried out. It was observed that the bed formation of the feedsample tended to overflow in the sample at low flux (10t/m2/day) and tended to underflow in the sampleat high flux (28.5t/m2/day). This meant that the long time at lower flux created an opportunity for fineparticles to settle easily, similar to coarser particles and as such, ore properties did not play a decisiverole in bed formation, but their effects appeared instead at higher flux. Furthermore, it was observed thatthe underflow concentration increased by decreasing the flux from 28.5 to 10t/m2/day. These increasingamounts were 0.05t/m3 and 0.12t/m3 in hydrocyclone overflow and underflow samples, respectively, at aheight of 2.5 metres. This meant that the compressibility and permeability of the hydrocycloneunderflow sample was much better than in the hydrocyclone overflow sample, which was clearly a resultof the ore properties (density, particle size, mineralogy).

Improvement of vehicle roll stability by varying suspension properties

Vehicle roll dynamics are strongly influenced by suspension properties such as roll centre height, roll steer, and roll camber. In this paper, the effects of suspension properties on vehicle roll response have been investigated using a multi-body vehicle dynamics programme. Roll dynamics of a vehicle model with MacPherson (front) and multilink (rear) suspensions were evaluated for the fishhook manoeuvre and variations of its roll response due to changes in the suspension properties were assessed by quantitatively analysing the vehicle response through simulation. Critical suspension design parameters for vehicle roll dynamics were identified and adjusted to improve roll stability of the vehicle model with passive suspension. Design of experiments has been used for identifying critical hardpoints affecting the suspension parameters, and optimisation techniques were employed for parameter optimisation. This approach provides a viable alternative to costlier active control systems for economy-class vehicles.

Ultrasonic dispersion of soil in water - the effect of suspension properties on energy dissipation and soil dispersion

The application of ultrasonic energy to soil-water suspensions for particle size analysis has been widely adopted and more recently applied to aggregate stability assessment. However, suspension properties have been reported to affect both the energy applied and the degree of aggregate breakdown. This paper investigates the effect of suspension concentration, suspension volume, gas saturation, depth of ultrasonic probe insertion and particle size distribution on the power (energy per unit time) applied by an ultrasonic probe. It also investigates the effect of suspension concentration, suspension volume, gas saturation and method of wetting the soil on the dispersion produced by ultrasonic energy applications. Where the power applied was expressed per unit soil mass, the quantity of dispersed material released by ultrasonic action was not affected by either the volume or concentration of the suspension. However, decreasing the dissolved gas concentration in suspension decreased the dispersion produced. The method of soil wetting significantly affected initial disruption but had no effect on the maximum amount of <2 and <20 �m material produced by sonification. The power applied by the ultrasonic probe was found to decrease with suspension temperature, increase with dissolved gas concentration and increase with the depth of probe insertion. Recommendations are made on the range of suspension properties that should be used for standard measurements of aggregate stability assessment using ultrasonic energy.