Soda-lime Glass Particles Research Articles

Enhanced Photoluminescence of Plasma-Treated Recycled Glass Particles.

Recycled soda-lime glass powder is a sustainable material that is also often considered a filler in cement-based composites. The changes in the surface properties of the glass particles due to the treatments were analyzed by X-ray photoelectron spectroscopy (XPS) and optical spectroscopy. We have found that there is a relatively high level of carbon contamination on the surface of the glass particles (around 30 at.%), so plasma technology and thermal annealing were tested for surface cleaning. Room temperature plasma treatment was not sufficient to remove the carbon contamination from the surface of the recycled glass particles. Instead, the room temperature plasma treatment of recycled soda-lime glass particles leads to a significant enhancement in their room temperature photoluminescence (PL) by increasing the intensity and accelerating the decay of the photoluminescence. The enhanced blue PL after room-temperature plasma treatment was attributed to the presence of carbon contamination on the glass surface and associated charge surface and interfacial defects and interfacial states. Therefore, we propose blue photoluminescence under UV LED as a fast and inexpensive method to indicate carbon contamination on the surface of glass particles.

Bis(2-ethylhexyl) phthalate transfer from polyvinyl chloride sheet to several kinds of particles

Bis(2-ethylhexyl) phthalate (DEHP) transfer from a polyvinyl chloride (PVC) sheet to 9 kinds of particles, namely, polyethylene particles (1–10, 45–53, 90–106 μm), soda lime glass particles (1–38, 45–53, 90–106 μm), black forest soil, carbon black, and cotton linter, for the particle weights of 0.3, 1, 3, and 12 mg/cm2, were determined for 1, 3, 7, and 14 days using a passive flux sampler (PFS), as well as standard dust. Transfer amounts to small polyethylene particles (1–10 μm), black forest soil, and carbon black were large (8.5, 16, and 48 μg/mg-particle, respectively, for 0.3 mg/cm2 for 14 days) and were similar to standard house dust (35 μg/mg-particle). On the other hand, transfer amount to large polyethylene particles (0.056–0.12 μg/mg-particle), soda lime glass (0.18–0.31 μg/mg-particle), and cotton linter (0.42–0.78 μg/mg-particle) were much lower. The DEHP transfer amount to the particles was proportional to the surface area of the particles, but not associated with the organic content. The DEHP transfer amount per surface area to small polyethylene particles was larger than that of other particles, suggesting the contribution of absorption into the polyethylene particle. However, for the larger polyethylene particles with different manufacturing process that may have different crystallinity, the contribution of absorption was small. The amount of DEHP transferred to soda lime glass did not differ from 1 to 14 days, suggesting that an adsorption equilibrium was reached after 1 day. The estimated value of particle/gas partition coefficients of DEHP, Kpg, of small polyethylene, black forest soil and carbon black were much higher (3.6, 7.1, and 18 m3/mg, respectively) than those of large polyethylene and soda lime glass particles (0.028–0.11 m3/mg).

Mesoscale shock structure in particulate composites

Multiscale experiments in heterogeneous materials and the knowledge of their physics under shock compression are limited. This study examines the multiscale shock response of particulate composites comprised of soda-lime glass particles in a PMMA matrix using full-field high speed digital image correlation (DIC) for the first time. Normal plate impact experiments, and complementary numerical simulations, are conducted at stresses ranging from 1.1−3.1GPa to elucidate the mesoscale mechanisms responsible for the distinct shock structure observed in particulate composites. The particle velocity from the macroscopic measurement at continuum scale shows a relatively smooth velocity profile, with shock thickness decreasing with an increase in shock stress, and the composite exhibits strain rate scaling as the second power of the shock stress. In contrast, the mesoscopic response was highly heterogeneous, which led to a rough shock front and the formation of a train of weak shocks traveling at different velocities. Additionally, the normal shock was seen to diffuse the momentum in the transverse direction, affecting the shock rise and the rounding-off observed at the continuum scale measurements. The numerical simulations indicate that the reflections at the interfaces, wave scattering, and interference of these reflected waves are the primary mechanisms for the observed rough shock fronts.

Roughness and humidity effects on contact, friction, and contact plasticity revealed by micromechanical testing and analysis

Understanding the effects of surface roughness, surface lubrication, and environmental conditions on inter-particle contact mechanics is important for a broad range of applications of granular materials. In this paper, a new micromechanical testing apparatus was developed and used to characterize smooth and rough soda lime glass particles in carefully controlled dry, humid, and lubricated environments during normal compression and shearing. From surface profilometry measurements and digital image correlation, we observed a humidity independent correlation between hysteresis, contact plasticity, and surface roughness in normal compression tests. From analysis of shear test data, we observed an increase in friction with increasing surface roughness, contact hold times, and water lubrication. Our work highlights roughness and environmental effects on contact and friction of silicate materials.

The effect of gas on tribocharging of particles in a vibrated bed

The total charges acquired by soda-lime glass particles and polyethylene particles were measured in a vibrated bed under a nitrogen or argon environment. The charge magnitudes were lower in argon compared to nitrogen. Complementary Discrete Element Method simulations using the gaseous dielectric strength as a constraint largely reproduce the experimental observations. The electric field was found to reach the breakdown constraint during particle-wall contact. The particle charge levels in argon were found to strongly correlate with gas breakdown. A simplified analysis using Gauss's law revealed that the charge levels in glass particle experiments are limited by dielectric breakdown associated with particle surface area and the charge levels in polyethylene particle experiments are limited by dielectric breakdown associated with the surface area of the bounding wall.

Alkali-silica reaction and strength of concrete with pretreated glass particles as fine aggregates

In this study, the strength and alkali-silica reaction (ASR) of concrete by incorporating pretreated soda-lime glass particles as fine aggregates were investigated.The glass aggregates were pretreated with three different solutions: Ca(OH)2, NaOH, and a mixture of Ca(OH)2 and NaOH.The glass aggregates were pretreated for 1, 4, and 7 days to investigate the time-dependent effect.Results show that the ASR was mitigated in all pretreatments.The effect was more noticeable with pretreatment in a mixed solution. The effect increased with an increase in pretreatment time.The ASR expansion was reduced by approximately 50% by pretreating the glass aggregate in the mixed solution at 80 °C for 7 days.Moreover, pretreatment of the glass aggregate was beneficial for strength improvement.For example, by pretreating the glass aggregate in the Ca(OH)2 solution at 80 °C for 7 days, the 28-day compressive strength demonstrated an approximate 6% increment compared with the specimen with non-pretreated glass aggregates.

Effect of particle size on tribocharging

Total charge acquired by soda-lime glass particles of two different sizes in nitrogen environment were measured in vibrated beds. A systematic difference of surface charge density was observed. Complementary Discrete Element Method simulations were performed to examine how this size dependence could be captured in a tribocharging model. Neither dielectric breakdown of the gas nor charge relaxation could explain the size dependence. A mechanistic model is not developed in this study, but experimental charge levels could be captured by allowing the effective work function (EWF) to be different for two particle sizes. The same EWF difference between the two sizes could capture the results obtained in vibrated beds of two different dimensions and two different wall materials. This approach was applied to examine the charging behavior of a bidisperse system studied experimentally. Their results could be reproduced if size dependent EWF is coupled with stochastic variation within each particle size.

Comparison between sinter forging and X-ray microtomography methods for determining sintering stress and bulk viscosity

The macroscopic sintering parameters, sintering stress, bulk viscosity, and shear viscosity, were measured by the discontinuous sinter forging experiment for viscous sintering of calcium aluminosilicate (CAS) glass. The calculated results were compared with experimental values from the microstructural evolution during viscous sintering of spherical soda lime glass particles by X-ray microtomography. The sintering stress of CAS glass normalized by surface energy and the initial particle size was in good agreement with values estimated from the microtomography data of soda lime glass, despite the differences in particle shape and chemical composition. The bulk viscosity obtained by discontinuous sinter forging agreed fairly well with that estimated by X-ray microtomography observation, when they were normalized by glass viscosity.

Fracture mechanisms of glass particles under dynamic compression

In this study, dynamic fracture mechanisms of single and contacting spherical glass particles were observed using high speed synchrotron X-ray phase contrast imaging. A modified Kolsky bar setup was used to apply controlled dynamic compressive loading on the soda-lime glass particles. Four different configurations of particle arrangements with one, two, three, and five particles were studied. In single particle experiments, cracking initiated near the contact area between the particle and the platen, subsequently fragmenting the particle in many small sub-particles. In multi-particle experiments, a crack was observed to initiate from the point just outside the contact area between two particles. The initiated crack propagated at an angle to the horizontal loading direction, resulting in separation of a fragment. However, this fragment separation did not affect the ability of the particle to withstand further contact loading. On further compression, large number of cracks initiated in the particle with the highest number of particle-particle contacts near one of the particle-particle contacts. The initiated cracks roughly followed the lines joining the contact points. Subsequently, the initiated cracks along with the newly developed sub-cracks bifurcated rapidly as they propagated through the particle and fractured the particle explosively into many small fragments, leaving the other particles nearly intact.

Durability of Mortar Made with Fine Glass Powdered Particles

Different studies investigate the use of waste glass in Portland cement compounds, either as aggregates or as supplementary cementitious materials. Nevertheless, it seems that there is no consensus about the influence of particle color and size on the behavior of the compounds. This study addresses the influence of cement replacement by 10 and 20% of the colorless and amber soda-lime glass particles sized around 9.5 μm on the performance of Portland cement mortars. Results revealed that the partial replacement of cement could contribute to the production of durable mortars in relation to the inhibition of the alkali-aggregate reaction. This effect was more marked with 20% replacement using amber glass. Samples containing glass microparticles were more resistant to corrosion, in particular those made of colorless glass. The use of colorless and amber glass microparticles promoted a reduction in wear resistance.

Contact properties determination of macroscopic fine disperse glass particles via compression tests under cyclic loading/unloading

To investigate the permanent compressive stress of single particles in a cohesive bulk solid during handling or transport, uniaxial compression tests were carried out with cyclic loading/unloading. This involves a continuation of our previous studies (contact properties determination of macroscopic fine disperse glass particles via compression tests in normal direction). The experiments were implemented by means of a home-built compression tester. By repeated loading/unloading cycles with spherical, dry and smooth soda lime glass particles with a mean diameter of d50,3=513.20μm, a set of micromechanical contact properties was determined. It is a model-based back-calculation of experimentally generated normal force-displacement curves of the elastic-plastic sample material. For this purpose, the contact model ‘stiff particles with soft contacts’, which was developed by Tomas, is used. In order to influence the flowability of soda lime glass particles and to verify the effect of the characteristic adhesion force on the elastic-plastic contact, the particles were altered to be hydrophilic and hydrophobic.Finally, the effect of the number of cyclic loading/unloading tests on the contact stiffness, the effective modulus of elasticity and the resulting contact radius was explained and discussed. According to this, there is an increase of the elastic-plastic contact stiffness up to a saturation of the plastic deformation during the repeated loading of the contact with a constant load rate of FN,max=45N.The determined residual plastic deformations in cyclic compression tests are directly correlated to the densification in the contact area of soda lime glass particles due to the absent long-range order in the glass structure.

Contact properties determination of macroscopic fine disperse glass particles via compression tests in normal direction

The paper describes the deformation behavior of spherical, dry and non-porous particles during a single particle compression test in normal direction. Therefore a compression tester was built. Industrial used soda lime glass particles with two macroscopic fine disperse sizes (d1,50,3=284.30μmand d2,50,3=513.20μm) were applied as model material to investigate the micromechanical contact behavior. In order to influence the elastic-plastic contact properties of particles, the surfaces were altered with chemical modification by means of silanization.The determination of various micromechanical contact properties (e.g. adhesion force, modulus of elasticity and contact stiffness) was carried out model-based with the contact model ‘stiff particles with soft contacts’ by means of a back-calculation.It could be shown that the model-based determination of material properties was a good alternative compared to the comprehensive tensile tests and pull-off force measurements.In addition to the gained normal force-displacement data in normal direction, the friction limits for tangential loading and rolling with the load-dependent adhesion force were model-based determined.

Pulse voltage determination for electrostatic micro manipulation considering surface conductivity and adhesion of glass particle

A model with surface conductivity and adhesional force is proposed to investigate the mechanism for electrostatic micro manipulation of a dielectric object using a single probe. The manipulation system consists of three elements: a conductive probe as a manipulator, a conductive plate as a substrate, and a dielectric particle as the target object for manipulation. The particle can be successfully picked up/placed if a rectangular pulse voltage is applied between the probe and the plate. The reliability of the picking up/placing operation is improved by applying a pulse voltage that is determined by a theoretical model considering surface conductivity and adhesion. To verify the theoretical prediction, manipulation experiment is conducted using soda-lime glass particles with radii of 20 μm and 40 μm.

Real-time measurement of alveolar size and population using phase contrast x-ray imaging.

Herein a propagation-based phase contrast x-ray imaging technique for measuring particle size and number is presented. This is achieved with an algorithm that utilizes the Fourier space signature of the speckle pattern associated with the images of particles. We validate this algorithm using soda-lime glass particles, demonstrating its effectiveness on random and non-randomly packed particles. This technique is then applied to characterise lung alveoli, which are difficult to measure dynamically in vivo with current imaging modalities due to inadequate temporal resolution and/or depth of penetration and field-of-view. We obtain an important result in that our algorithm is able to measure changes in alveolar size on the micron scale during ventilation and shows the presence of alveolar recruitment/de-recruitment in newborn rabbit kittens. This technique will be useful for ventilation management and lung diagnostic procedures.

Particle size effects in particle-particle triboelectric charging studied with an integrated fluidized bed and electrostatic separator system.

Fundamental studies of triboelectric charging of granular materials via particle-particle contact are challenging to control and interpret because of foreign material surfaces that are difficult to avoid during contacting and measurement. The measurement of particle charge itself can also induce charging, altering results. Here, we introduce a completely integrated fluidized bed and electrostatic separator system that charges particles solely by interparticle interactions and characterizes their charge on line. Particles are contacted in a free-surface fluidized bed (no reactor walls) with a well-controlled fountain-like flow to regulate particle-particle contact. The charged particles in the fountain are transferred by a pulsed jet of air to the top of a vertically-oriented electrostatic separator consisting of two electrodes at oppositely biased high voltage. The free-falling particles migrate towards the electrodes of opposite charge and are collected by an array of cups where their charge and size can be determined. We carried out experiments on a bidisperse size mixture of soda lime glass particles with systematically varying ratios of concentration. Results show that larger particles fall close to the negative electrode and smaller particles fall close to the positive electrode, consistent with theory and prior experiments that larger particles charge positively and smaller particles charge negatively. The segregation of particles by charge for one of the size components is strongest when its collisions are mostly with particles of the other size component; thus, small particles segregate most strongly to the negative sample when their concentration in the mixture is small (and analogous results occur for the large particles). Furthermore, we find additional size segregation due to granular flow, whereby the fountain becomes enriched in larger particles as the smaller particles are preferentially expelled from the fountain.

Indirect measurement of interfacial melting from macroscopic ice observations.

Premelted water that is adsorbed to particle surfaces and confined to capillary regions remains in the liquid state well below the bulk melting temperature and can supply the segregated growth of ice lenses. Using macroscopic measurements of ice-lens initiation position in step-freezing experiments, we infer how the nanometer-scale thicknesses of premelted films depend on temperature depression below bulk melting. The interfacial interactions between ice, liquid, and soda-lime glass particles exhibit a power-law behavior that suggests premelting in our system is dominated by short-range electrostatic forces. Using our inferred film thicknesses as inputs to a simple force-balance model with no adjustable parameters, we obtain good quantitative agreement between numerical predictions and observed ice-lens thickness. Macroscopic observations of lensing behavior have the potential as probes of premelting behavior in other systems.

Development of A-scan ultrasound technique for measuring local particle concentration in slurry flows

The effects of solid particle concentration on hydraulic performance and wear need to be considered during the design of slurry transport equipment used in the petroleum and mining industries. The acoustic properties of slurry flows such as velocity, backscatter, and attenuation as a function of volume fraction of solid particles are examined in this study. An ultrasound A-mode imaging method is developed to obtain particle concentration in a flow of soda lime glass particles (diameter of 195 μm) and water slurry in a 0.0254 m diameter pipe. Based on the acoustic properties of the slurry, a technique is developed to measure local solid particle concentrations. The technique is used to obtain concentration profiles in homogeneous (vertical flow) and non-homogeneous (horizontal flow) slurry flows with solid particle concentrations ranging from 1 to 10% by volume using a window size of 0.159 cm. The profiles show average concentration within each window vs. distance from the transducer face. For horizontal flow, profiles are obtained for average flow velocities of 2.0, 3.0, and 3.5 m/s. The algorithm developed utilizes the power spectrum and attenuation measurements obtained from the homogeneous loop as calibration data in order to obtain concentration profiles in other (i.e. non-homogenous) flow regimes. A computational study using FLUENT is performed and a comparison is made with the experimental results. Reasonable agreement between the experimental and computational results is observed. The ultrasound technique has proven to be useful in characterizing slurry flows containing concentrations too high to be investigated using optical techniques.

高粒子濃度条件での選択的液中造粒による粒子分離効率

Particle separation by selective wet agglomeration was investigated for a suspension with particle concentration of 10-40vol%. The suspension consisted of calcium carbonate particles and soda lime glass particles, with median diameters of 9.2μm and 18.6μm respectively. Dodecane was used as a bridging liquid. The fluidity of suspension decreased with an increase in particle concentration, and the wet agglomeration process was affected by the fluidity of the suspension. However, the influence of fluidity on particle separation efficiency was small. The particle separation efficiency by selective wet agglomeration became high at a high particle concentration, and the maximum separation efficiency of 0.93 was attained at the particle concentration of 40vol%. By surface treatment of suspended particles and bridging liquid droplets, the particle separation efficiency markedly changed due to the change in adhesion tension.

Protein adsorption from flowing solutions on pure and maleic acid copolymer modified glass particles

The adsorption of human serum albumin (HSA) and lysozyme (LSZ) on pure as well as maleic acid (MA) copolymer coated spherical soda lime glass particles was investigated under flowing conditions. Coating the glass particles with two different maleic acid copolymers alters the properties of the particle surface concerning its charge and hydrophobicity in a well-defined gradation. Frontal chromatography was used to determine the surface concentration of the adsorbed proteins and to establish adsorption isotherms. The introduced methodology was demonstrated to provide a powerful means to study protein adsorption at solid/liquid interfaces. Investigations with virginal and protein-preadsorbed glass particles revealed that even under streaming conditions HSA is irreversibly adsorbed, whereas LSZ partially desorbs. For LSZ and HSA the adsorbed amounts and the isotherms strongly depend on the surface “history”, i.e. the presence or absence of preadsorbed protein layers, and the kind of surface modification of the glass. Compared to the soda lime glass surface the adsorption of HSA was strongly increased on surfaces modified with a hydrophobic maleic acid copolymer indicating a strong hydrophobic protein–surface interaction. By coating the surface with a hydrophilic and more negatively charged maleic acid copolymer the adsorption of HSA to that surface was lower and comparable to the adsorption onto plain glass due to the electrostatic repulsion between HSA and the modified surface. In contrast the affinity to any of the investigated particle surfaces was generally higher for LSZ than for HSA which can be mainly attributed to the electrostatic attraction between LZS and the surface. The adsorbed amount of LSZ on the copolymer coated particle surfaces was much higher than on the pure soda lime glass particles indicating superposed hydrophobic interactions in the case of the hydrophobic MA copolymer layer and an increased density of anionic sites as well as interactions of LSZ within the three-dimensional (swollen), hydrophilic MA copolymer layer.

In Situ Observation of Glass Particle Sintering

This article introduces the sintering process to chemistry students unfamiliar with the subject. The concepts are discussed and a movie is included showing the viscous flow sintering process of glass particles. Frenkel's model, which describes the viscous flow process, was applied to demonstrate its validity. Spherical soda-lime glass particles were heat treated at 750 °C in an optical microscope equipped with a hot stage. The glass sintering process was recorded using a digital camera coupled to the microscope. During sintering, the particle boundaries moved apart until the interface separating them was flat, subsequently joining to become a single particle as a result of the decrease in superficial free energy. Frenkel's model was verified for the vitrification process and for ceramic shrinkage during sintering. Two graphs indicate experimental measurements similar to those in Frenkel's model.