scholarly journals Determination of the Rate of Salt-Induced Rapid Coagulation of Polystyrene Latex Particles in Turbulent Flow Using Small Stirred Vessel

2018 ◽  
Vol 3 (1) ◽  
pp. 5
Author(s):  
Oktaviani Oktaviani ◽  
Yasuhisa Adachi
Keyword(s):  
Ad Hoc ◽  
Coupling Effect ◽  
Particle Diameter ◽  
Polystyrene Latex ◽  
Stirred Vessel ◽  
Colloidal Spheres ◽  
Rapid Coagulation ◽  
Mixing Intensity ◽  
Mixing Rates ◽  
Different Diameters

In our study, we revisited a previously reported method for evaluating the mixing intensity of uniform colloidal spheres in terms of their collision frequency, with the aim of evaluating the validity of this method in the case of a small stirred vessel equipped with an impeller with four paddles. The rates of the salt-induced rapid coagulation of polystyrene latex (PSL) particles with five different diameters were measured as functions of the rotation rate. The ad-hoc assumption of the linear additivity of the perikinetics and the orthokinetics of the coagulation process was used for the analysis. Our previously proposed equation for the rate of turbulent coagulation as a function of the particle diameter, determined for an end-over-end rotation mixing device, was confirmed to be valid. However, it was found that, for small particles and low-mixing rates, i.e., for low Peclet numbers, the rate of coagulation becomes larger than that predicted on the basis of linear additivity because of the coupling effect of Brownian motion and the fluid flow during turbulent mixing. This increase occurred even though the rate was lowered by the wall effect, which resulted in an inhomogeneous distribution of the mixing intensity.

scholarly journals Calibration of the passive cavity aerosol spectrometer probe for airborne determination of the size distribution

2013 ◽  
Vol 6 (3) ◽  
pp. 4123-4152 ◽  
Author(s):  
Y. Cai ◽  
J. R. Snider ◽  
P. Wechsler
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Scattered Light ◽  
Particle Diameter ◽  
Polystyrene Latex ◽  
Calibration Methods ◽  
Research Aircraft ◽  
Amplifier Gain ◽  
Gain Stage

Abstract. This work describes calibration methods for the particle sizing and particle concentration systems of the passive cavity aerosol spectrometer probe (PCASP). Laboratory calibrations conducted over six years, in support of the deployment of a PCASP on a cloud physics research aircraft, are analyzed. Instead of using the many calibration sizes recommended by the PCASP manufacturer, a relationship between particle diameter and scattered light intensity is established using three sizes of mobility-selected polystyrene latex particles, one for each amplifier gain stage. In addition, studies of two factors influencing the PCASP's determination of the particle size distribution – amplifier baseline and particle shape – are conducted. It is shown that the PCASP-derived size distribution is sensitive to adjustments of the sizing system's baseline voltage, and that for aggregate spheres, a PCASP-derived particle size and a sphere-equivalent particle size agree within uncertainty dictated by the PCASP's sizing resolution. Robust determination of aerosol concentration, and size distribution, also require calibration of the PCASP's aerosol flowrate sensor. Sensor calibrations, calibration drift, and the sensor's non-linear response are documented.

Swelling of Latex Particles

1959 ◽  
Vol 32 (3) ◽  
pp. 814-824
Author(s):  
Maurice Morton ◽  
Samuel Kaizerman ◽  
Mary W. Altier
Keyword(s):  
Molecular Weight ◽  
Particle Size ◽  
Interfacial Energy ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Polystyrene Latex ◽  
Average Particle ◽  
Equilibrium Solubility ◽  
Latex Particles ◽  
Equilibrium Swelling

Abstract A theoretical relation has been derived for the equilibrium swelling of latex particles. The equilibrium solubility and rate of solution of solvents were measured on a series of polystyrene latex fractions of varying particle size. The solvents used were styrene, toluene, and chlorocyclohexane. It was found, as predicted by theory, that the equilibrium amount of solvent imbibed by latex particles is a direct function of the particle diameter and an inverse function of the interfacial energy at the surface of the particles. The molecular weight of the polymer has no effect on the equilibrium swelling, within the range from 100,000 to several million molecular weight units. The rate of imbibition of these solvents appears to be extremely rapid, indicating that equilibrium solubility would appear to be maintained in most polymerization reactions. The fact that a particular solvent is a “good” solvent for the polymer does not necessarily result in a greater swelling of the particles, since the solvent may show a higher interfacial energy against the aqueous phase. The soap titration method is best for determining the average particle size of a latex for purposes of predicting equilibrium swelling.

Clogging mechanisms of filter barriers against debris-flow hazard

2021 ◽  
Author(s):  
Filippo Mauro ◽  
Alessandro Leonardi ◽  
Marina Pirulli
Keyword(s):  
Debris Flows ◽  
Large Diameter ◽  
Particle Diameter ◽  
Small Diameter ◽  
Equivalent Diameter ◽  
Threshold Values ◽  
Different Diameters ◽  
Debris Flow Hazard ◽  
Key Parameter

<p>Debris flows are amongst the most hazardous landslide phenomena (Jakob & Hungr, 2005). They are mixtures of flowing water and granular materials, which range in size from microscopic soil particles to massive rock boulders. Due to their unpredictability and rapidity, they pose severe hazard on infrastructure, structures, and human lives. To dissipate the destructive kinetic energy of debris flows and induce deposition of the coarsest fraction of the flow, mitigation systems often include the use of filter barriers. Filter barriers are built both in steel and reinforced concrete, and their openings should be designed according to a reference grain diameter. This key parameter is often chosen arbitrarily due to the difficulties in considering the full grain size distribution of the deposit. Sufficiently small outlets, however, leads to premature clogging of the barriers, blocking further outflow (Ashour et al., 2017). This can result in excessive maintenance costs.</p><p>This work focuses on the clogging mechanism of three different kinds of filter barriers: nets, slit dams, and slot dams. The aim is to evaluate the influence of grainsize dispersity into the clogging/non-clogging transition. Starting from simpler monodisperse granular material, we determine via DEM simulations the particle diameter D that induces clogging in the openings, as a function of the opening size S. Thus, for monodisperse grains, a set of threshold values for S/D can be detected: on one side of the threshold the particles are too small to clog the opening, on the other side they are too large to allow free passage of the material.</p><p>However, natural debris deposits are far from uniform. To analyse the role of grainsize dispersity, bidisperse specimens are created mixing grains with two different diameters: a small diameter and a large diameter. By varying the composition of large and small particles, a transition is observed between clogging and free-flow, in analogy with what obtained in the simulation with monodisperse grains. The comparison of results obtained with bidisperse and monodisperse samples indicates that an analogy in terms of trends and thresholds exists, as long as an equivalent diameter D* is introduced for bidisperse mixtures (Marchelli, 2018). This parameter is therefore suggested as the reference diameter to be adopted in the barrier design.</p>

scholarly journals Rapid coagulation of polystyrene latex in a stopped-flow spectrophotometer

1974 ◽  
Vol 49 (2) ◽  
pp. 281-285 ◽  
Author(s):  
J.W.Th Lichtenbelt ◽  
C Pathmamanoharan ◽  
P.H Wiersema
Keyword(s):  
Polystyrene Latex ◽  
Stopped Flow ◽  
Rapid Coagulation

scholarly journals Study of impact of sonic energy waves on the rate of precipitation of particles in liquid

2021 ◽  
Author(s):  
Abdisamed Sheik-Qasim
Keyword(s):  
Settling Velocity ◽  
Particle Density ◽  
Particle Diameter ◽  
Hydroxypropyl Cellulose ◽  
Fluid Viscosity ◽  
Small Particles ◽  
Particle Settling ◽  
Sonic Energy ◽  
Different Diameters ◽  
Good Agreement

The effects of sonic energy waves on the settling velocity of small particles in water were studied. A design of experiment (DOE) with five variables (frequency, amplitude, particle diameter, particle density and fluid viscosity) at two or three levels was conducted to obtain the particle settling velocity as the response. The DOE data were analyzed both experimentally and by a statistical multiple regression software. It was concluded that when sound frequency and amplitude in the range of 0 to 500 Hz and 2 to 3 Vrms (root mean square) respectively were applied to plastic particles of three different diameters (2,381 μm, 3,175 μm, and 4,763 μm) and two different densities ... their effects on the particle settling velocity in hydroxypropyl cellulose (HPC) solutions of three different viscosities ... were insignificant. The regression analysis gave an equation that is in good agreement with the experimental data.

scholarly journals Calibration of the passive cavity aerosol spectrometer probe for airborne determination of the size distribution

2013 ◽  
Vol 6 (9) ◽  
pp. 2349-2358 ◽  
Author(s):  
Y. Cai ◽  
J. R. Snider ◽  
P. Wechsler
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Scattered Light ◽  
Particle Diameter ◽  
Polystyrene Latex ◽  
Calibration Methods ◽  
Research Aircraft ◽  
Amplifier Gain ◽  
Gain Stage

Abstract. This work describes calibration methods for the particle sizing and particle concentration systems of the passive cavity aerosol spectrometer probe (PCASP). Laboratory calibrations conducted over six years, in support of the deployment of a PCASP on a cloud physics research aircraft, are analyzed. Instead of using the many calibration sizes recommended by the PCASP manufacturer, a relationship between particle diameter and scattered light intensity is established using three sizes of mobility-selected polystyrene latex particles, one for each amplifier gain stage. In addition, studies of two factors influencing the PCASP's determination of the particle size distribution – amplifier baseline and particle shape – are conducted. It is shown that the PCASP-derived size distribution is sensitive to adjustments of the sizing system's baseline voltage, and that for aggregates of spheres, a PCASP-derived particle size and a sphere-equivalent particle size agree within uncertainty dictated by the PCASP's sizing resolution. Robust determinations of aerosol concentration, and size distribution, also require calibration of the PCASP's aerosol flowrate sensor. Sensor calibrations, calibration drift, and the sensor's non-linear response are documented.

scholarly journals Modeling the Thermal Performance of Falling Particle Receivers Subject to External Wind

2019 ◽  
Author(s):  
Brantley Mills ◽  
Reid Shaeffer ◽  
Clifford K. Ho ◽  
Lindsey Yue
Keyword(s):  
Flow Rate ◽  
Thermal Performance ◽  
Power Plants ◽  
Particle Diameter ◽  
Concentrating Solar Power ◽  
Strong Function ◽  
Significant Parameter ◽  
Solar Power Plants ◽  
Different Diameters ◽  
Numerical Parametric Study

Abstract Falling particle receivers (FPRs) are an important component of future falling particle concentrating solar power plants to enable next-generation energy generation. High thermal efficiencies in a FPR are required to high thermodynamic efficiencies of the system. External winds can significantly impact the thermal performance of cavity-type FPRs primarily through changing the air flow in and out of the aperture. A numerical parametric study is performed in this paper to quantify the effect of wind on the thermal performance of a FPR. Wind direction was found to be a significant parameter that can affect the receiver thermal efficiency. The particle mass flow rate did not significantly change the overall effect of wind on the receiver. The receiver efficiency was strong function of the particle diameter, but this was primarily a result of varying curtain opacity with different diameters and not from varying effects with wind. Finally, the model was used to demonstrate that receiver efficiencies of 90% were achievable under the assumption that the effect of wind/advective losses were mitigated.

scholarly journals Study of impact of sonic energy waves on the rate of precipitation of particles in liquid

2021 ◽  
Author(s):  
Abdisamed Sheik-Qasim
Keyword(s):  
Settling Velocity ◽  
Particle Density ◽  
Particle Diameter ◽  
Hydroxypropyl Cellulose ◽  
Fluid Viscosity ◽  
Small Particles ◽  
Particle Settling ◽  
Sonic Energy ◽  
Different Diameters ◽  
Good Agreement

The effects of sonic energy waves on the settling velocity of small particles in water were studied. A design of experiment (DOE) with five variables (frequency, amplitude, particle diameter, particle density and fluid viscosity) at two or three levels was conducted to obtain the particle settling velocity as the response. The DOE data were analyzed both experimentally and by a statistical multiple regression software. It was concluded that when sound frequency and amplitude in the range of 0 to 500 Hz and 2 to 3 Vrms (root mean square) respectively were applied to plastic particles of three different diameters (2,381 μm, 3,175 μm, and 4,763 μm) and two different densities ... their effects on the particle settling velocity in hydroxypropyl cellulose (HPC) solutions of three different viscosities ... were insignificant. The regression analysis gave an equation that is in good agreement with the experimental data.

New Particle Metrology for CMP Slurries

2007 ◽  
Vol 991 ◽  
Author(s):  
Kim Williams ◽  
Ilyong Park ◽  
Edward E. Remsen ◽  
Mansour Moinpour
Keyword(s):  
Flow Field ◽  
Large Particle ◽  
Colloidal Silica ◽  
Polystyrene Latex ◽  
Particle Sizing ◽  
Field Flow Fractionation ◽  
Counting Method ◽  
Dual Sensor ◽  
Different Diameters ◽  
Further Development

ABSTRACTA new particle sizing and counting method based on the coupling of flow field-flow fractionation (FFF) with dual-sensor, single particle optical sensing (SPOS) detection is reported. The integration of FFF and SPOS systems was accomplished by means of a dilution interface that preserved the resolution of FFF-separated particles. Analysis of a model mixture of polystyrene latex standards of different diameters established that the FFF-SPOS system can resolve particles into discrete peaks for subsequent particle counting. Application of this method for the analysis of a colloidal silica standard demonstrated its use for materials commonly employed as CMP abrasives. Further development and refinement of the technique will enable compositional and structural analyses of heterogeneous large particle populations constituting commercial CMP slurries.

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