Small Glass Particles Research Articles

Impact-related chemical modifications of the Chang’E-5 lunar regolith

Impact events on the Moon have been recognized as modifying the composition of surface materials through processes such as shock metamorphism and mixing with exotic components. Previous studies have indicated that the regolith sampled by the Chinese Chang’E-5 mission was primarily evolved from local mare basalts, likely originating from a single episode of effusive volcanism. The relatively simple and monotonic protolith of the Chang’E-5 regolith presents a unique opportunity to investigate the chemical modifications induced by impact events. In this study, we conducted detailed petrographic and mineralogical analyses on a diverse set of lunar regolith samples, including thirty-three small impact glass particles (39–227 μm), one large agglutinate (∼1.6 mm), and sixteen basaltic clasts (0.1–1.6 mm). Numerical modeling was also conducted to quantitatively assess the melting behavior of basaltic clasts under different impact conditions. Our primary objective was to evaluate the chemical variations of impact glass in relation to lithic clasts. While the majority of homogeneous impact glass spherules and larger basaltic clasts (≥1 mm) exhibit similar bulk compositions (e.g., Al2O3, CaO and FeO) to the local regolith, we recognize additional effects of impact processes, including impact comminution, impact melting and crystallization, differential volatilization, and potentially selective melting. These processes have modified the texture and geochemistry of lunar regolith components. The chemical signatures of small clasts in the Chang’E-5 regolith indicate that the fine size fractions (e.g., those with diameters of ≤ 300 μm) are predominantly composed of lithic and monomineralic fragments with a substantial proportion being dominated by mesostasis. Melting of these sub-millimeter fractions may lead to the formation of impact glass with chemical compositions deviating from the average local regolith. These results have implications for understanding the compositional evolution of the Chang’E-5 regolith. Notably, our study suggests that impact glasses spherules with different major (e.g., TiO2, MgO) and minor (e.g., REEs, Zr, Th and U) element compositions could be derived from the same protolith of local mare basalts, instead of being exclusively attributed to exotic impact ejecta. In this case, small-scale local impacts may have played a crucial role in the impact history of the Chang'E-5 landing site.

Multidisciplinary management in the treatment of intrahepatic cholangiocarcinoma.

Multidisciplinary management in the treatment of intrahepatic cholangiocarcinoma.

Designing minimally segregating granular mixtures for gravity‐driven surface flows

AbstractIn dense flowing bidisperse particle mixtures varying in size or density alone, smaller particles sink (percolation‐driven) and lighter particles rise (buoyancy‐driven). But when particle species differ from each other in both size and density, percolation and buoyancy can either enhance (large/light and small/heavy) or oppose (large/heavy and small/light) each other. In the latter case, a local equilibrium can exist in which the two mechanisms balance and particles remain mixed: this allows the design of minimally segregating mixtures by specifying particle size ratio, density ratio, and mixture concentration. Using DEM simulations, we show that mixtures specified by the design methodology remain relatively well‐mixed in heap and tumbler flows. Furthermore, minimally segregating mixtures prepared in a fully segregated state in a tumbler mix over time and eventually reach a nearly uniform concentration. Tumbler experiments with large steel and small glass particles validate the DEM simulations and the potential for designing minimally segregating mixtures.

Refractive index measurement of the smallest bulk and surface glass microfragments in a model case

The refractive index measurement is a widely used investigation method of glass microtraces in forensic laboratories. The advantage of the method, in addition to its cost efficiency and repeatability, is that it is suitable for examining small fragments. In the present study, a real case was simulated, and fragments smaller than 250micrometers obtained from five pieces of clothing, after breaking a pane of float glass, were investigated. In addition to the known (control) sample, altogether 25 bulk and 83 recovered surface fragments were also examined. In the first step, only one measurement was performed for each fragment to simulate the investigation of small fragments and test their measurability without crushing. All the bulk fragments met with the matching criterion Kmin ≤Q≤Kmax , in which Kmin and Kmax are the minimum/maximum value of the measured refractive indices of the known sample, while Q is the measured (mean) value of the questioned fragment. However, the matching ratio was only approximately 60% for the surface fragments according to the one-edge measurements. After crushing, the false exclusion rate was significantly reduced, and 79 of the 83 recovered surface fragments met with the matching criterion. As a result of crushing, not only the probability of matching, but also the edge count values improved significantly. Although the refractive index is only one property examined in the totality of glass analysis, the results of the present work can significantly contribute to the determination of the origin of small glass particles in real forensic cases.

Diagnostic yield of cone beam computed tomography for small foreign body detection in the hand in comparison with radiography, MSCT and MRI: an ex vivo study

IntroductionDetection of symptomatic foreign bodies (FB) after penetrating hand injuries can be challenging. Multiplanar radiography is most frequently used for FB detection and may be complemented by multislice computed tomography (MSCT) if suspected FBs cannot be identified and clinical symptoms are persisting. Cone beam computed tomography (CBCT) is a promising imaging modality for traumatology aside from fracture detection. The aim of this study was to evaluate the diagnostic yield of CBCT for different small FBs in the hand in comparison with radiography, MSCT and magnetic resonance imaging (MRI). MethodsIn ten cadaveric hands of voluntary body donors, 20 different FBs (metal, glass, stone, wood, thorn) in predefined sizes (0.5, 1 and 2mm) were randomly placed in the central hand and the basal phalanges. All hands were imaged using radiography, 256-slice CT, CBCT, and 3T MRI. A total of 200 subcutaneous and intramuscular particles were analyzed for their visibility by two observers at two time points. The Cohens Kappa coefficient was calculated as a measure of interobserver agreement and intraobserver reliability. The particle detection rate between different imaging modalities was compared using McNemar Chi2-tests. ResultsCBCT and MSCT provided a higher detection rate (94.6% and 86.3%) for detecting metal, glass and stone particles compared to standard radiography (70.0%; each p<0.001). MRI did not provide a diagnostic benefit. Wood particles and thorns were not reliably recognizable by any imaging technique. The interobserver agreement (K=0.768; p<0.001) and the intraobserver reliability for both observers (K1=0.914 and K2=0.907; p<0.001) were good. The dose length product (DLP) was 2-fold lower in CBCT than in MSCT (39.2 ± 2.1 vs. 81.4 ± 2.9 mGy*cm; p<0.001). ConclusionsIn this ex vivo study, CBCT provided a high detection rate for small metal, glass, and stone particles while the radiation exposure was significantly lower compared to MSCT. These results suggest that CBCT instead of MSCT seems a reasonable option in supplementary diagnostics to exclude of FBs. The primary use of CBCT instead of radiography may be considered for symptomatic patients with expected small radiopaque particles <1mm. Organic FBs can be visualized indirectly in MRI and CBCT/MSCT by entrapped surrounding air. Level of EvidenceLevel I, diagnostic study.

Electrostatic Separation of Copper and Glass Particles in Pretreated Automobile Shredder Residue

There is increasing demand for an efficient technique for separating automobile shredder residue (ASR) obtained from end-of-life vehicles (ELVs). A particular challenge is the physical separation of conductive materials from glass. In this study, the performance of pretreatment and induction electrostatic separation process was evaluated. The results show that a sieving/washing (combination of sieving and washing) pretreatment was the most effective for removing conductive material compared to electrostatic separation alone. The optimum separation efficiency of copper products was achieved with an applied voltage of 20 kV, a relative humidity of less than 35%, and a splitter position of 8 cm. Although the separation efficiency was slightly reduced when some small glass particles remained attached to the conductive materials, the separation efficiency of copper from the pretreated ASR dramatically increased to 83.1% grade and 90.4% recovery, compared to that of raw ASR (34.3% grade and 58.6% recovery). Based on these results, it was demonstrated that the proposed sieving/washing pretreatment was proficient at removing conductive materials from glass; thus, it has the potential to significantly improve the efficiency of electrostatic separation for ASR.

Sintering behavior and characteristics study of BaTiO3 with 50 wt% of B2O3-Bi2O3-SiO2-ZnO glass

The thermal analysis of B2O3-Bi2O3-SiO2-ZnO (BBSZ) glass with different particle sizes and LiF addition was researched to study its temperature behavior. Next the composites with 50wt% BaTiO3–50wt% BBSZ glass were prepared for shrinkage, microstructures and dielectric properties investigations. The differently treated BBSZ glass showed that the smaller glass particles clearly decreased its softening and crystallization temperatures. LiF addition had the same but much weaker effect.The composites showed two-stage shrinkage related to the softening of the glass and new phase generation of Bi24Si2O40 at 385–450°C, and Bi4BaTi4O15 over 680°C. The microstructures of the composites sintered at 720°C showed Bi4BaTi4O15, BaTiO3 and Bi24Si2O40 with residual ZnO phase. LiF addition increased the amount of Bi4BaTi4O15, thus increasing the loss value. However the particle size of the glass did not effect to the dielectric properties of the composites showing permittivity of 248–256 and loss of 0.013 at 100kHz.

Neutron detector based on Particles of 6Li glass scintillator dispersed in organic lightguide matrix

Most 3He replacement neutron detector technologies today have overlapping neutron–gamma pulse-height distributions, which limits their usefulness and performance. Different techniques are used to mitigate this shortcoming, including Pulse Shape Discrimination (PSD) or threshold settings that suppress all gammas as well as much of the neutrons. As a result, count rates are limited and dead times are high when PSD is used, and the detection efficiency for neutron events is reduced due to the high threshold. This is a problem in most applications where the neutron–gamma separation of 3He detectors had been essential. This challenge is especially severe for neutron coincidence and multiplicity measurements that have numerous conflicting requirements such as high detection efficiency, short die-away time, short dead time, and high stability. 6Li-glass scintillators have excellent light output and a single peak distribution, but they are difficult to implement because of their gamma sensitivity. The idea of reducing the gamma sensitivity of 6Li-glass scintillators by embedding small glass particles in an organic light-guide medium was first presented by L.M. Bollinger in the early 60s but, to the best of our knowledge, has never been reduced to practice. We present a proof of principle detector design and experimental data that develop this concept to a large-area neutron detector. This is achieved by using a multi-component optical medium (6Li glass particles attached to a glass supporting structure and a mineral oil light guide) which matches the indices of refraction and minimizes the absorption of the 395nm scintillator light. The detector design comprises a 10in. long tube with dual end readout with about 3% volume density of 6Li glass particles installed. The presented experimental data with various neutron and gamma sources show the desired wide gap between the neutron and gamma pulse height distributions, resulting in a true plateau in the counting characteristics similar to that of 3He detectors.

Leveraging electronic health records to notify pediatric patients of a drug recall.

Drug recalls have become an unfortunately frequent event in the United States, with nearly 1 clinically relevant drug recall per month in the last 5 years.1 A national management strategy on medical device recalls is currently being debated by government and health officials.2 We report the use of the National Institutes of Health–sponsored Informatics for Integrating Biology &Bedside (i2b2) platform3 as an approach to speed patient identification and direct notification of a voluntary drug recall by leveraging data available in the electronic health record (EHR). On November 9, 2012, specific lots of the generic version of atorvastatin calcium, distributed by Ranbaxy Pharmaceuticals Inc, a subsidiary of a multinational corporation, were reported as possibly contaminated with “very small glass particles resembling a fine grain of sand.”4 A voluntary recall was announced by the company and reported to the general public by news organizations. A US Food and Drug Administration (FDA) notice on November 28, 2012, recommended that patients contact their health care provider with any symptoms related to taking the medication and health care providers report any suspected adverse events to the FDA. A team of physicians, a nurse practitioner, and a nurse who provide clinical care in the Preventive Cardiology program at Boston Children’s Hospital felt obligated to inform the pediatric patients prescribed atorvastatin and their families of the drug recall in a targeted and efficient approach to (1) identify those at risk and (2) prevent unnecessary discontinuation of beneficial treatment.

Recycling Glass Cullet from Waste CRTs for the Production of High Strength Mortars

The present paper reports on the results of some experiments dealing with the recycling of mixed cathode ray tube (CRT) glass waste in the production of high-strength mortars. Waste CRT glass cullet was previously milled, and sieved, and the only fine fraction was added to the fresh mortar in order to replace part of the natural aggregate. The addition of superplasticizer was also investigated. All hydrated materials displayed high compressive strength after curing. Samples containing CRT mixed glass showed a more rapid increase of strength with respect to the reference compositions, and materials with a superplasticizer content of 1% showed the best overall performance due to the favourable influence of the small glass particles which increase the amount of silicate hydrated produced. The induced coupled plasma (ICP) analysis made on the solutions, obtained from the leaching tests, confirmed the low elution of hazardous elements from the monolithic materials produced and consequently their possible environmental compatibility.

Effects of worker size on the dynamics of fire ant tunnel construction

Social insects work together to complete tasks. However, different individuals within a colony may vary in task proficiency. We investigated if fire ant (Solenopsis invicta) worker body size influenced the ability to construct tunnels--a key component of subterranean nests. We monitored excavation by worker groups in a substrate of small wetted glass particles in quasi-two-dimensional arenas. Morphological and network features of the tunnel system were measured. Total tunnel area did not differ significantly between groups of large and small workers, although the tunnel area of control sized workers was significantly larger than that of large workers. Moreover, large workers created wider but shorter tunnels, with slower growth rate of tunnel number. However, edge-vertex scaling and degree distribution of the tunnel network were similar across all treatments. In all cases, the amount of excavated material was correlated with the number of active workers. Our study reveals that morphological features of excavated tunnels show modest variation when constructed by workers of varying sizes, but topological features associated with the tunnel network are conserved. These results suggest that important behavioural aspects of tunnel construction--and thus nest building--are similar among morphologically distinct members of fire ant societies.

Silver coated bioactive glass particles for wound healing applications

Bioactive glass particles (0.42SiO(2)-0.15CaO-0.23Na(2)O-0.20ZnO) of varying size (<90 μm and 425-850 μm) were synthesized and coated with silver (Ag) to produce Ag coated particles (PAg). These were compared against the uncoated analogous particles (Pcon.). Surface area analysis determined that Ag coating of the glass particles resulted in increased the surface area from 2.90 to 9.12 m(2)/g (90 μm) and 1.09-7.71 m(2)/g (425-850 μm). Scanning electron microscopy determined that the Ag coating remained at the surface and there was little diffusion through the bulk. Antibacterial (Escherichia coli--13 mm and Staphylococcus epidermidis--12 mm) and antifungal testing (Candida albicans--7.7 mm) determined that small Ag-coated glass particles exhibited the largest inhibition zones compared to uncoated particles. pH analysis determined an overall higher pH consider in the smaller particles, where after 24 h the large uncoated and Ag coated particles were 8.27 and 8.74 respectively, while the smaller uncoated and Ag coated particles attained pH values of 9.63 and 9.35 respectively.

Effects of BaO–SiO 2 glass particle size on the microstructures and dielectric properties of Mn-doped Ba(Ti, Zr)O 3 ceramics

The sintering behavior, microstructures and dielectric properties of Mn-doped Ba(Ti, Zr)O 3 (BTZ) ceramics with different particle sizes of BaO–SiO 2 glass (D50 ranging between 185 and 1200 nm) were investigated. From the metallographic observation, adding finer glass frit revealed more homogeneous compositional distribution. It was found that better spreading of the glass phase could be achieved by adding finer glass particles that could penetrate the BTZ ceramic interface more easily, thus enhancing the grain growth. The extent of the incorporation between glass and ceramic increased with smaller glass particles, and the Curie temperature was altered accordingly. Microstructural evaluation conducted by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) with an energy-dispersive X-ray spectrometer (EDS) indicated the glass particle size has a dramatic influence on the sintering behavior and microstructure of Mn-doped BTZ ceramics. The relationship between microstructures and dielectric properties was also discussed in this study.

Numerical simulation for the collision between a vortex ring and solid particles

This study is concerned with the numerical simulation for the collision between a vortex ring and an ensemble of small glass particles. The vortex ring, convecting with its self-induced velocity in a quiescent air, collides with the particles. The Reynolds number for the vortex ring is 2600, and the particle diameters are 50 and 200 μm. The Stokes number St for the 50 μm particle is 0.74, while the St for the 200 μm particle is 11.4. Immediately after the collision with the vortex ring, the 50 μm particles surround the vortex ring, forming a dome. It is parallel with the preferential distribution for the particle with St ≃ 1 around large-scale eddies, which has been measured experimentally and simulated numerically in various free turbulent flows. The 200 μm particles disperse more due to the collision with the vortex ring. This is attributable to the centrifugal effect of large-scale eddy, which has been reported by the numerical simulation for the motion of the particle with St = 10 in a wake flow. The collision between the vortex ring and the particles induces an organized three-dimensional vortical structure. It also reduces the strength and convective velocity of the vortex ring.

Two-Dimensional Grid-Free Simulation Method for Gas-Particle Two-Phase Flow Based on Vortex Method

This study proposes a two-dimensional grid-free simulation method for gas-particle two-phase flow. The method is based on a vortex method, in which the vorticity field is discretized by vortex elements. The behavior of vortex element and the particle motion are simultaneously computed by the Lagrangian approach. Four square cells are allocated around each particle. In each cell, the change in the circulation of gas-phase due to the particle motion is calculated, and it is considered through the change in the strength of vortex element. The grid-free method is applied to simulate the particulate jet generated by small glass particles falling from a slit orifice into an unbounded quiescent air. It is shown that the simulated distribution of air velocity is favorably compared with the measurement. It is also confirmed that the entrained air flow rate agrees well with the prediction by an analytical model. These results suggest the validity of the method.

Kinetic Modeling of LTCC Shrinkage: Effect of Alumina Content

We studied sintering of LTCC-type glass matrix composites (GMCs) consisting of small glass and alumina particles of equal size. Primarily, crystals act as rigid inclusions, decelerating the densification rate. In later stages, they also dissolve, partially increasing the viscosity. Release of alumina finally induces crystallization of alumosilicates, which enables post-firing stability. To study both effects, two model GMCs were prepared: an α-Al2O3 + barium alumoborosilicate glass (BABS)–GMC, which shows neither significant dissolution nor crystallization, and an α-Al2O3 + calcium alumoborosilicate glass (CABS)–GMC, which dissolves readily and promotes crystallization. The kinetics of shrinkage for both GMC were modeled by utilizing Frenkel theory for the early stage and Mackenzie–Shuttleworth theory for the late stage, assuming that sintering is superimposed by the weighted contributions of triparticle glass–crystal clusters, their random occurrence (ideal mixing), and a shrinkage rate controlled by the GMC effective viscosity. In agreement with modeling, the experimental results showed that the shrinkage rate of BABS–GMC decreases progressively for crystal volume fractions Φ &amp;gt; 0.15. The attainable shrinkage is reduced by up to 8% for Φ = 0.45. For the CABS–GMC with Φ = 0.25, a reduction of Φ to 0.20 was evident due to partial α-Al2O3 dissolution. This effect was found able to increase the sintering temperature by ~50–60 K.

Experimental determination of particles capture efficiency in flotation

A single bubble experiment is developed for the determination of the capture efficiency by rising bubbles in a uniform concentration of small inertialess glass particles under carefully controlled hydrodynamics and physico-chemical conditions. Air bubbles (0.35–1.3 mm in diameter) rise and reach their terminal velocity in clean water before passing through a suspension of particles (15– 56 μ m in size), where capture takes place. After passing through another zone containing pure water to remove particles trapped in their wake, bubbles release captured particles at the surface from where the particles are collected and counted. A capture efficiency is then calculated as the ratio of the number of particles captured by one rising bubble to the number of particles present in the volume swept out by this bubble. Capture efficiencies range between 10 - 3 and 5 × 10 - 1 and are in the order of magnitude of the experimental results presented by Ralston and Dukhin [1999. The interaction between particles and bubbles. Colloids and Surfaces A: Physicochemical and Engineering Aspects 151, 3–14] as well as of numerical results for collision efficiency presented by Sarrot et al. [2005. Determination of the collision frequency between bubbles and particles in flotation. Chemical Engineering Sciene 60 (22), 6107–6117].

Three-Dimensional Vortex Method for Gas-Particle Two-Phase Compound Round Jet

This paper proposes a three-dimensional vortex method for a gas-particle two-phase compound round jet. The method can take account of the interaction between the two phases by calculating the motion of particles and the behavior of gas vortex elements through the Lagrangian approach. In order to discuss the validity of the method, an air jet, loaded with small glass particles, issuing from a round nozzle into the co-flowing air stream is simulated. The simulation demonstrates that the air turbulence modulations due to the particles, such as the relaxation of velocity decay, the decrement of momentum diffusion in the radial direction at the fully developed region, and the reduction of turbulent intensity and Reynolds shear stress, are successfully captured by the method.

Three-Dimensional Vortex Method for Gas-Particle Two-Phase Compound Round Jet

We propose a three-dimensional vortex method for a gas-particle two-phase compound round jet. The method can take account of the interaction between the two phases by calculating the motion of particles and the behavior of gas vortex elements through the Lagrangian approach. In order to discuss the validity of the method, an air jet, loaded with small glass particles, issuing from a round nozzle into the co-flowing air stream is simulated

三次元渦法による固気二相同軸円形噴流の数値解析(OS1-7噴流、せん断流の拡散、輸送,噴流、後流及びせん断流の基礎と応用)

We propose a three-dimensional vortex method for a gas-particle two-phase compound round jet. The method can take account of the interaction between the two phases by calculating the motion of particles and the behavior of gas vortex elements through the Lagrangian approach. In order to discuss the validity of the method, an air jet, loaded with small glass particles, issuing from a round nozzle into the co-flowing air stream is simulated