Sizes Of Glass Beads Research Articles

Effects of Glass Bead Size on Dissolution Profiles in Flow-through Dissolution Systems (USP 4).

The effects of glass bead size in the conical space of flow-through cells on the dissolution profiles were investigated in a USP apparatus 4. Dissolution tests of disintegrating and non-disintegrating tablets in flow-through dissolution systems were performed using semi-high precision glass beads with diameters ranging from 0.5mm to 1.5mm. Computational fluid dynamics (CFD) was used to evaluate the effect of shear stress from the dissolution media flow. The use of smaller glass beads in a larger cell resulted in a faster dissolution of the model formulations under certain test conditions. The effect on the dissolution was highly dependent on the size of the beads in the top layer, including those in contact with the tablets. The absence of a bead-size effect on the dissolution of an orodispersible tablet in a small cell can be explained by the floating fragments during the test. CFD analysis showed that smaller bead diameters led to greater shear stress on the tablet, which was correlated with the dissolution rate. Hence, fluid flow through the narrow gaps between the small beads generated strong local flows, causing shear stress. The size of the glass beads used in flow-through cells affects the dissolution rate of tablets by altering the shear stress on the tablets in certain cases (e.g., direct deposition of the formulation on glass beads, large cells, and very low flow rates). Thus, glass bead size must be considered for a robust dissolution test in a flow-through cell system.

Jet injection and spout formation in a fluidized bed

A single jet was studied in a rectangular fluidized bed by analyzing the pressure fluctuations data to characterize the jet hydrodynamics. The bed contained with glass beads of different mean sizes (450, 650, and 920 µm) as well as pharmaceutical pellets (920 µm). The analysis of the pressure fluctuation data was performed using the power spectral density function (PSDF) and discrete wavelet transforms technique. This study investigated how the flow regime changed from a jet in a fluidized bed to a spouted regime as the gas injection velocity was increased. Increasing the mean particle size led to an increase in the minimum spouting velocity. The minimum spouting velocity for 450, 650, and 920 μm glass bead particles and for 920 μm pharmaceutical pellets were determined to be 32.47 m s-1, 38.66 m s-1, 44.78 m s-1, and 44.47 m s-1, respectively. The study also examined how the dominant frequency of the various particles and the energy percentage of scales changed with increasing injection velocities. The ratio of energy percentages of meso-scale changes as the injection velocity increases and these changes were used to estimate the minimum spouting velocity. Wavelet sub-signals analysis revealed that the Daubechies 2 (DB2) wavelet was the most effective at capturing the characteristics of the jet. Based on the Shannon entropy of the approximate coefficients, the wavelet analysis showed that 11 levels of decomposition were required. By combining the wavelet analysis and PSDF, a more detailed analysis of the meso-scale was achieved. This study provided valuable insights into the behavior of jets and spouts in fluidized beds, which can greatly contribute to the optimization of a jet in fluidized beds and spout-fluidized beds by enhancing our understanding of jet behavior in such environments.

Experimental and modeling insights into mixing-limited reactive transport in heterogeneous porous media: Role of stagnant zones

The understanding of mixing-controlled reactive dynamics in heterogeneous porous media remains limited, presenting significant challenges for modeling subsurface contaminant transport processes and for designing cost-effective environmental remedial efforts. The complexity of accurately observing, measuring, and modeling mixing-limited reactive transport has led to inadequate exploration of these critical processes. This study investigates the mixing and reaction kinetics affected by stagnant zones, which are commonly found in alluvial aquifers-aquitards and fracture-matrix systems. By conducting experiments involving conservative and bimolecular reactive transport through porous media within translucent chambers filled with two sizes of glass beads and under varying flow rates, we explored the effects of grain size and hydrodynamic conditions. Using a high-resolution camera, we monitored the concentration changes of conservative and reactive tracers, with subsequent interpretation through three-dimensional numerical simulations. The outcomes revealed the emergence of distinct mixing interfaces within both mobile and stagnant zones, culminating in a bi-peaked plume formation. Notably, the mixing and reaction times in media containing stagnant zones were found to be approximately 10 times longer than in homogeneous media. These findings, through experimental and modeling efforts, advance our understanding of mixing-limited reactive transport phenomena within heterogeneous media, underscoring the significant role of stagnant zones—a topic previously underexplored.

Experimental investigation of erosion and transport of binary sediment in sewer pipes

ABSTRACT Understanding sediment transport in storm sewer systems is essential to prevent pipe blockages, associated flooding, and maintenance. In this research, a laboratory study was conducted in a pipe to investigate the erosion and transport process of a binary sediment, i.e., a material with two different particle sizes. The sediment used in this study was a mixture of two sizes of spherical glass beads (0.8 and 4 mm) and two sizes of natural soil (sand and gravel), with different amounts of small size particles. The results show that the critical velocities for the initiation of sediment transport increase linearly with a decrease in the fine particle content of the mixture. A method to predict the critical velocity of a binary mixture is proposed based on the fine content and the critical velocity of single-size large particle and single-size small particle sediments. The transport rate of the mixture lies between that of the single-size large sediment and single-size small sediment. The transport rate is increased with an increase in the fine content, which means that mixing small particles with large particles can significantly increase the transport rate of large particles and the total transport rate.

Effect of gravel pack permeability on horizontal well productivity loss under secondary methane hydrate formation: Experimental optimization of 3D randomly distributed mixed sand pack

Horizontal well productivity is limited by secondary hydrate formation (temperature drop results from endothermic of hydrate dissociation) during production. Seepage capacity as one of the key indexes for evaluating production efficiency, and efficiency is declined by sand production. Sand control is achieved by using gravel pack technology (selected sands for hindering the sediments particles migration), which extends the production time. However, forecasting the productivity decline trend from quantifying the permeability of the gravel pack after secondary formation remain challenges. To address these issues, a randomly distributed 3D normalized permeability (Kr) model was developed to describe the seepage capacity of gravel pack composed by various particle sizes of mixed glass beads. The theoretical modelling was established by observing micro spatial structure of glass beads with hydrate formation. The new model considered three consolidation modes of hydrate in pores (cementing + bearing, pore filling, and grain coating) and linked them with the productivity ratio equation of a horizontal gas well. To confirm the viability of the model, a series of permeability measurement experiments with various size ratios (α) from 1 to 10 were conducted. Finally, errors comparison and all parameters of the model were analyzed. The results showed that the productivity ratio declined clearly after saturation is >0.79, when α = 4. For long-term production, α = 10 would be better. The new model can help hydrate horizontal wells increase production from laboratory to industrial exploitation. KeyPoints•Secondary hydrate formation permeability model in gravel pack was established.•After secondary saturation's effect on horizontal well production was developed.•Gravel pack was simulated by random non-coincident particles with varies size ratios.•When the size ratio is 4, productivity ratio of horizontal well was extended.

Raman Spectroscopy of Disperse Systems with Varying Particle Sizes and Correction of Signal Losses.

In this paper, a dispersion of glass beads of different sizes in an ammonium nitrate solution is investigated with the aid of Raman spectroscopy. The signal losses caused by the dispersion are quantified by an additional scattered light measurement and used to correct the measured ammonium nitrate concentration. Each individual glass bead represents an interface at which the excitation laser is deflected from its direction causing distortion in the received Raman signal. It is shown that the scattering losses measured with the scattered light probe correlate with the loss of the Raman signal, which means that the data obtained can be used to correct the measured values. The resulting correction function considers different particle sizes in the range of 2-99 µm as well as ammonium nitrate concentrations of 0-20 wt% and delivers an RMSEP of 1.952 wt%. This correction provides easier process access to dispersions that were previously difficult or impossible to measure.

Field Data Analysis of Pavement Marking Retroreflectivity and Its Relationship with Paint and Glass Bead Characteristics

Pavement marking retroreflectivity, a critical factor for safe driving, depends on the characteristics of both the paint and the embedded glass beads. However, traditional methods for predicting pavement marking service life often overlook these materials properties. This study investigates the influence of paint and glass bead characteristics on pavement marking retroreflectivity performance and addresses the characterization of glass bead size distribution by the coefficient of uniformity and curvature. Three field test sites on a Brazilian highway with various paint and glass bead combinations were evaluated. A statistical model, GAMLSS (Generalized Additive Model for Location, Scale, and Shape), was adjusted to evaluate the performance of the markings’ retroreflectivity as a function of paint and glass bead characteristics. The model revealed that well-graded glass beads increased retroreflectivity by around 10%, while paints with a higher volume of solids improved service life around 65%. Therefore, the results show that acrylic water-based paints with higher volumes of solids and well-graded glass beads with better shape characteristics should be preferred to improve pavement markings’ retroreflectivity and service life. The statistical model identified the key characteristics with the greatest impact on pavement marking retroreflectivity, offering valuable insights for real-world applications, which will assist pavement marking practitioners and road authorities in selecting appropriate materials to achieve enhanced durability.

Environmentally Friendly Synthesis of Polymer Nanoparticles in a Packed Reactor Using Glass Beads

AbstractPolymeric particles less than 100 nm in size (polymer nanoparticles), which are useful in the fields of medicine and so on, are synthesized through emulsion polymerization, wherein surfactants are essential for maintaining their dispersion stability, contaminating particle surfaces and causing high environmental pollution. The soap‐free emulsion polymerization (SFEP) of styrene in a packed reactor using microglass beads enables the synthesis of polymer nanoparticles without surfactants. Ultraviolet irradiation is used for radical polymerization using an initiator during the SFEP of styrene. The reaction space in the packed reactor is controlled by the size of glass beads to be filled in the reactor. A decrease in the size of the glass beads narrows the reaction space, causing the average polystyrene particle size to reach 27.3 nm and suppress convection flow by the wall of the glass beads, thereby limiting particle motion and preventing particle growth through particle collisions.This article is protected by copyright. All rights reserved

Development of red mud-modified geopolymer coating with radiative cooling effect for footway application

Radiative cooling coating technology is gaining increasing attention in the context of mitigating urban heat island and tackling global climate change. This paper is concerned with the development of an inorganic geopolymer-based radiative cooling coating using red mud, incorporating varying sizes of TiO2 and hollow glass beads. The developed colored coating demonstrates its radiative cooling capability in reducing the surface temperature by harnessing the potential of red mud. The physico-chemical properties, surface morphology, and element distribution of the coating were characterized by XRD, FTIR, TG-DAT, SEM and EDS. The coating exhibited lower UV (0.0844) and visible reflectance (0.5275) but high NIR reflectance (0.7536), as well as high infrared emissivity of 0.9455, enabling a red color with a CIE value of L* = 74.56, a* = 9.55, and b* = 11.98, and a maximum temperature reduction of 7.3 °C under the climate of Hong Kong. Additionally, the skid resistance, abrasive resistance and adhesion strength of the proposed coating could meet the requirements of standards, indicating a great potential for footway applications.

Experimental Study of the Generation of Pore Gas Pressure in Pyroclastic Density Currents Resulting From Eruptive Fountain Collapse

AbstractPyroclastic density currents formed through collapse of eruptive fountains commonly have runout distances of the order of tens of kilometers. A possible cause of this high flow mobility is elevated interstitial pore gas pressure, which may have various origins. We investigated experimentally the generation of pore pressure at the impact zone of an eruptive fountain, where concentrated pyroclastic density currents emerge from compaction of a free falling gas‐particle mixture. We simulated pyroclastic fountain collapse by releasing glass beads of mean sizes of 29–269 µm from a hopper at height of 3.27 m above a 5 m‐long horizontal channel, and we measured pore air pressure in the impact zone. During free fall, the granular mixtures accelerated and expanded to reach particle concentrations of 1.6–4.4 vol.% before they impacted the base of the channel. Upon impact, the particles accumulated to form concentrated granular flows with particle concentrations of 45–48 vol.% and pore air pressures that indicated almost full weight support for particle sizes ≤76 µm. Both the amount of pore pressure in the impact zone and the flow runout distance increased as we decreased the particle size and hence the hydraulic permeability of the concentrated granular mixtures. Our results suggest that pore gas pressure in concentrated pyroclastic density currents can be generated at the impact zone of collapsing fountains and that small particle size conferring low permeability and long pore pressure diffusion timescale is one of the main causes of long flow runout distances.

Laminar Free Convection In Horizontal Annulus Filled With Glass Beads And With Annular Fins On The Inner Cylinder

An experimental and numerical study has been carried out to investigate the heat transfer by natural convection and radiation in a two dimensional annulus enclosure filled with porous media (glass beads) between two horizontal concentric cylinders. The outer cylinders are of (100, 82 and70mm) outside diameters and the inner cylinder of 27 mm outside diameter with (or without) annular fins attached to it. Under steady state condition; the inner cylinder surface is maintained at a high temperature by applying a uniform heat flux and the outer cylinder surface at a low temperature inside a freezer. The experiments were carried out for an annulus filled with glass beads at a range of modified Rayleigh number (4.9 ≤ Ra≤ 69), radiation parameter (0<Rd<10), with fin length of (Hf=3, 7 and 11mm), with radius ratios of (Rr=(r1/r2) =0.1405,0.2045, 0.293 and 0.3649 ), number of fins (n=0, 12, 23 and 45). Finite difference method with Boussinesq's approximation is used to solve the continuity, energy and momentum equations. The numerical solution is capable of calculating the streamline, the temperature field, the velocity field, the local and average Nusselt number. A computer program in Mat lab has been built to carry out the numerical solution. The numerical study was done for a range of modified Rayleigh number (4.9 ≤ Ra ≤ 300). Results show that the average Nusselt number is nearly constant for Ra less than 100 and increased with an increase in modified Rayleigh number.Nusselt number hardly affected by glass beads size and insignificant affected by Rd for Ra less than 100. Decreasing Rr cause clearly increase in average Nusselt number and increasing fin length or fin number decrease heat transfer.

Scale Dependence of Dispersion Coefficient for Solute Transport in Porous Media Using Image Analysis

Scale dependence of dispersion coefficient (D) in the advection-dispersion equation (ADE) for solute transport in porous media was investigated by a series of experiments using image analysis. A hexahedral plexiglass box sized 200×8×1.5 cm (L×W×H) was set and packed with glass beads as porous media. The solute transport under different conditions was simulated by changing the particle size of glass beads, flow rate, and detection scale using Bright Blue as tracer. The image analysis method was used to dynamically monitor and identify the spatiotemporal variation of solute concentration distribution. The results showed that image analysis can effectively monitor and identify the solute concentration in porous media, as indicated by an R2 value of 0.9890. There is an obvious linear relationship between hydraulic gradient (J) and velocity (v) in porous media under different experimental conditions. The ADE model is suitable for solute breakthrough curve (BTC) with good fitting accuracy, and can effectively reflect the concentration variation during solute transport. The key parameters controlling the solute transport were analyzed. D has abnormal diffusion (i.e., non-Fickian phenomenon) and scale dependence, and BTCs had a long tail, which becomes more obvious with the increase of flow rate, medium particle size, and transport scale.

Entrainment probability of coal particle by bubble trailing vortex in coal flotation

Understanding the effect of bubble trailing vortex on particle trajectory is an important precursor for reducing the ash content of coal flotation. Using a high-speed motion acquisition system, we investigated the coal particle trajectory around the cylinder. Two typical trajectories of coal particles around the cylinder were measured. Some particles settled down out of the trailing vortex region while some ones flowed up. The effects of particle density, particle size and fluid flow velocity on the entrainment probability was analyzed. The entrainment probability gradually increased as the coal particle size decreased, increased as the particle density decreased, and increased as the fluid flow velocity increased. The entrainment probability obviously increased as the particle flowability increased independently of particle size, and the increase in the entrainment probability mainly concentrated in the range of particle flowability less than 12.5. The flotation of glass beads was conducted. The flotation recovery increased as the glass bead size decreased, which matched well with the predicted entrainment probability. Our results can provide a valuable insight into the development of flotation technology for cleaner mineral flotation.

Characterization of Bubble Transport in Porous Media Using a Microfluidic Channel

This study investigates the effect on varying flow rates and bubble sizes on gas–liquid flow through porous media in a horizontal microchannel. A simple bubble generation system was set up to generate bubbles with controllable sizes and frequencies, which directly flowed into microfluidic channels packed with different sizes of glass beads. Bubble flow was visualized using a high-speed camera and analyzed to obtain the change in liquid holdup. Pressure data were measured for estimation of hydraulic conductivity. The bubble displacement pattern in the porous media was viscous fingering based on capillary numbers and visual observation. Larger bubbles resulted in lower normalized frequency of the bubble breakthrough by 20 to 60 percent. Increasing the flow rate increased the change in apparent liquid holdup during bubble breakthrough. Larger bubbles and lower flow rate reduced the relative permeability of each channel by 50 to 57 percent and 30 to 64 percent, respectively.

Removal of powders from cavities in contaminated surfaces by shock and plasma generated by an adjacent electro-static discharge

An electrostatic discharge (ESD) produced between pin electrodes above a cavity filled with powder is explored as means of contactless removal of particles from contaminated surfaces. The ESD is produced by discharging a capacitor through an air gap. Glass beads of different sizes serve as model powders filling cavities of different depths. Masses of both loaded and ejected powders are measured. The motion of the ejected particles is studied using high-speed video. Most of the ejected particles move vertically up with the initial velocities varied from ca. 4 to 11 m/s. Changing the mechanical properties of the substrate holding the powder does not significantly affect the velocities of the ejected particles. For powders removed from cavities as a result of interaction with the shock and plasma produced by ESD, the number of particle layers ejected is determined by the particle size and the ESD energy, but is not significantly affected by the cavity depth. A single ESD pulse can be effective in the complete removal of powder particles from relatively shallow, 0.2-mm deep cavity. Estimates suggest that the particles are primarily ejected due to the lift forces produced by local velocity gradients of the gas above the loaded powder layer.

Extraction of astaxanthin from fermentedAcetesusing virgin coconut oil with the glass beads vortex method

Astaxanthin is an antioxidant that can be extracted from crustaceans such as shrimp, lobster, crawfish, and crabs. FermentedAcetesshrimp (called cincalok) is a traditional side dish from Indonesia rich in astaxanthin. This study extracted astaxanthin from cincalok using the glass beads vortex method with virgin coconut oil (VCO) as a green solvent. Several parameters that affect the amount of astaxanthin extracted, such as the ratio between sample and solvent, contact time, and particle size of glass beads, have been tested. The physicochemical characteristics of VCO before and after extraction were also analyzed. The UV-Vis spectrophotometer analysis results showed that the optimum ratio between sample and solvent was 1:10 g/mL, the optimum contact time was 15 minutes, and the optimum particle size of the glass beads was 60–80 mesh. Under these optimum conditions, the amount of astaxanthin extracted was 27.97 μg/g dry weight of cincalok or 2.79 μg/mL VCO. After extraction, the viscosity and density of VCO still meet the Indonesian National Standard with values of 17.98 mm2/s and 917.2 kg/m3, respectively. Before and after extraction, the GC-MS chromatogram shows the main component of fatty acids in VCO is lauric acid, with a percentage of 27.28 and 26.72%, respectively. VCO can also extract omega-3 fatty acids DHA and EPA from cincalok with the same rate of 0.04%.

Effect of cell density on decrease in hydraulic conductivity by microbial calcite precipitation

The effect of number of cells deposited on decrease in hydraulic conductivity of porous media using CaCO3 precipitation induced by Sporosarcina pasteurii (ATCC 11,859) was examined in columns packed with glass beads in the range of 0.25 mm and 3 mm in diameter. After resting Sporosarcina pasteurii cells were introduced into the columns, a precipitation solution, which consisted of 500 mM CaCl2 and 500 mM urea, was introduced under continuous flow conditions. It was shown that hydraulic conductivity was decreased by formation of microbially induced CaCO3 precipitation from between 8.37 * 10−1 and 6.73 * 10−2 cm/s to between 3.69 * 10−1 and 1.01 * 10−2 cm/s. The lowest hydraulic conductivity was achieved in porous medium consisting of the smallest glass beads (0.25 mm in diameter) using the highest density of cell suspension (OD600 2.25). The number of the deposited cells differed depending on the glass bead size of the columns. According to the experiments, 7 * 10−9 g CaCO3 was produced by a single resting cell. The urease activity, which led CaCO3 precipitation, depended on presence of high number of cells deposited in the column because the nutrients were not included in the precipitation solution and consequently, the amount of CaCO3 precipitated was proportional with the cell number in the column. A mathematical model was also developed to investigate the experimental results, and statistical analysis was also performed.

Terminal velocity of fern and lycopod spores is affected more by mass and ornamentation than by size.

Terminal velocity (Vt) is an important factor for the dispersal of biological particles but has scarcely been studied for anemochorous fern spores, and the influence of spore characteristics on Vt has not been evaluated. Here, we measured the Vt of 1234 spores of 18 fern species and two Selaginella microspores using videoimaging analysis and evaluated the effects of mass, size, and ornamentation on Vt. We designed a sedimentation tower with a graduated microtelescope attached to a high-speed video camera to record falling particles and measure the Vt of fern spores using video-image processing software. Spores were measured for each species and their size correlated with Vt. The Vt of fern spores ranged from 4.7 cm·s-1 (Cyathea costaricensis) to 18.85 cm·s-1 (Acrostichum danaeifolium). The method is accurate and reliable as predicted by Stokes model for glass beads of known density and size. In addition, Vt had a higher correlation coefficient with mass (ρ = 0.72) than size (ρ = 0.20), and ornamental appendages reduced Vt. The reported values of Vt of fern spores are within the range of different biological airborne particles such as moss spores and pollen grains of seed plants. The results showed that spore ornamentation is directly related to Vt rather than spore size and may increase or decrease the drag. This method will aid future aerobiological research on biological particles.

Model Test of the Water and Sand Mixture Inrush in the Mining-Induced Caving Zone

In western China coal mines, the mining-induced caving zone is regarded as a main pathway for water and sand inrush mixture hazards. The paper experimentally studied the flow behavior and the mechanism of water and sand mixture through mining-induced caving zones. Transport experiments are performed by using a laboratory-scale model, and the caving zone is modelled by using different sizes of glass beads. Four different sand sizes are used for the sand layer. The test results reveal that the mass flow rate of sand and water mixture increases with the increase of the initial water head. And an equation is proposed for the mass flow rate of sand and water mixtures that correctly reproduces the data for all the conditions. In addition, the sudden decreases in water head loss is monitored at the commencement of the water and sand flow, which would result in a large number of sand particles that rapidly start up and make the kinetic energy transfer from water to sand.

Rapid formation of methane hydrate in environment-friendly leucine-based complex systems

Given the growing demand for natural gas (NG) in energy supply systems worldwide, solidified natural gas (SNG) is viewed as a potential NG storage and transportation method owing to its numerous advantages. However, using significant amounts of sodium dodecyl sulfate (SDS) to improve its slow formation kinetics has a negative influence on the environment, and severe foaming hinders the system's recovery. To overcome the associated issues, the main promoter has been chosen to be the ecologically safe and non-foaming L-leucine, with low concentrations of SDS and NaCl, as well as glass beads of various particle sizes, added to achieve synergistic effects. The hydrophobic micro-regions created by the leucine molecules, as well as the porous hydrate characteristics, considerably enhanced hydrate formation in the leucine-based complex system. At the effective promotion concentration, the SDS dosage is reduced by 60–90%. Owing to their strong promotion effect and non-foaming feature, yielding almost non-toxic properties, the LS1 and LN4 systems may be employed commercially. With a target of advancing SNG technology, this study serves as a reference for future developments of SNG technology based on the idea of environmental friendliness.