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There is extensive geologic evidence of ancient volcanic activity on the Moon, but it is unclear how long that volcanism persisted. Magma fountains produce volcanic glasses, which have previously been found in samples of the Moon’s surface. We investigated ~3000 glass beads in lunar soil samples collected by the Chang’e-5 mission and identified three as having a volcanic origin on the basis of their textures, chemical compositions, and sulfur isotopes. Uranium-lead dating of the three volcanic glass beads shows that they formed 123 ± 15 million years ago. We measured high abundances of rare earth elements and thorium in these volcanic glass beads, which could indicate that such recent volcanism was related to local enrichment of heat-generating elements in the mantle sources of the magma. [ABSTRACT FROM AUTHOR]

Highlights Glass fiber‐reinforced resin matrix composites are widely used and studied for their good mechanical and impact resistance properties. In this paper, five glass fiber reinforced nylon 6 (PA6)‐based composites were prepared by mechanical blending combined with the molding process. The flexural strength, shear strength, pendulum impact strength, and low‐velocity impact properties of five composites were comparatively investigated. The crack extension modes of the composites were characterized and analyzed by light microscopy, scanning electron microscopy (SEM), and computerized X‐ray tomography (XCT), and the effects of different crack extension modes on the mechanical and impact resistance properties of the composites were researched. Experimental results show that: (1) Cracks in the composite material mainly exist in two expansion modes: transverse propagation parallel to the direction of fiber layup and longitudinal propagation perpendicular to the direction of fiber layup; (2) Different crack extension modes will cause different damage situations to the composites, however, the crack extension mode has minimal impact on the flexural, shear and pendulum impact strength of the composites; (3) The flexural and shear strengths of the composites co‐reinforced using fly ash and glass fibers were preferably 484.5 and 46.1 MPa; (4) The crack extension mode has a significant impact on low‐velocity impact performances of the composite material. The composite co‐reinforced with glass beads (GB) and glass fibers had the best impact resistance, with maximum impact force (Pmax), residual impact force (Pr), and absorbed energy (Ea) of 7015.2 N, 6273.6 N and 15.4 J, respectively. The propagation of cracks inside the composites was observed using SEM and XCT etc. A relationship between crack propagation mode and low‐velocity impact resistance of composites was established. The low‐velocity impact properties of composites are carefully analyzed. [ABSTRACT FROM AUTHOR]

Oxytetracycline (OTC) is frequently detected in groundwater and soil, posing substantial risks to the subsurface environment via persistence, phytotoxicity, changing bacterial communities, and antibiotic resistance. In situ chemical oxidation (ISCO) is one of the best alternatives for removing OTC from groundwater. However, its feasibility has rarely been investigated using columns for which optimal conditions can be obtained for practical applications. Thus, a system consisting of oxygen-doped graphitic carbon nitride (OgCN) and peroxymonosulfate (PMS) (OgCN/PMS) was tested for OTC removal using continuous-flow experiments with columns packed with sand and glass beads (GBs). The sand column exhibited better adsorption and degradation of OTC than the GB column in pulse injection experiments, regardless of whether OgCN was packed. Additional experiments were performed using a column saturated with the OTC solution and another filled with deionized water to simulate ISCO, using GB as the medium, to evaluate the net OTC removal by catalytic oxidation, excluding adsorption. Performance improved with increased OgCN packing, PMS dosage, retention time, and pH. Anions slightly affected the performance due to scavenging and propagation of radicals. These findings indicate the high potential of OgCN/PMS for ISCO and the usefulness of column experiments in field applications. [ABSTRACT FROM AUTHOR]

The aim of the current study is to provide evidence regarding the influence of particle size on the dynamic properties in granular materials. Experiments using a resonant column (RC) device were conducted on glass beads having similar coefficient of uniformity, but four different mean grain sizes to describe the tendencies in the magnitude of Gmax and Emax. It can be clearly seen that for similar particle gradation the influence of particle size is significant, in particular for larger mean grain sizes d50 exceeding 1·5 mm. The experimental data were fitted using existing empirical relationships with corresponding fitting parameters. The fitting parameters describing the void ratio and pressure dependence to estimate maximum stiffness were found to depend on grain size to a certain extent. This influence was diminished for the materials with a d50 < 1·5 mm. It was therefore possible to use a unique set of fitting parameters for these materials with a satisfying degree of accuracy. The results were compared with some previous studies to highlight the size dependency of Gmax and Emax for materials with mean size greater than 2 mm, but also the relatively small influence on materials with lower mean particle sizes (d50 < 2 mm) is acknowledged. The results are furthermore discussed through a micromechanical interpretation highlighting why larger grain sizes influence stiffness values. [ABSTRACT FROM AUTHOR]

The induced polarization (IP) method holds a strong potential to better characterize the critical zone of our planet especially in areas characterized by multi‐phase flow. Power‐law relationships between the bulk, surface, and quadrature conductivities versus the pore water saturation are potentially useable to map the subsurface water content distribution. However, the saturation exponents n and p in these power‐law relationships have been observed to vary with the texture of geomaterials and the wettabilities of pore fluids. Traditional experimental setups in the laboratory do not allow to independently visualize the pore fluid distribution. Therefore, the physical interpretations of the two saturation exponents have remained unclear. We developed a novel milli‐fluidic micromodel using clay‐coated glass beads that exhibit excellent visibility and high IP response. Through laboratory experiments, we simultaneously determined the micromodel complex conductivity and acquired the corresponding pore‐scale fluid distributions generated by drainage and imbibition through such class of porous materials. Finite‐element simulations of complex conductivity based on the upscaling of the complex surface conductance of grains were conducted to determine the saturation exponents under ideal pore fluid distributions. Results indicate that saturation exponents n and p vary depending on the ganglia size of the insulating fluids. The saturation exponents n and p exhibit power‐law relationships with the change rate of pore water connectivity with saturation, which is calculated through the computation of the derivative of Euler characteristics. These findings provide a new physical explanation to the relationships between the saturation exponents and the microscopic fluid distributions within the geomaterials. Plain Language Summary: Water saturation of porous bodies can be related to the complex conductivity through power‐law relationships. The existence of these power‐law relationships has been clearly documented in the literature. They are critical in the realm of hydrogeophysics to better characterize the critical zone of the solid Earth. However, the values of the saturation exponents in these power‐laws have been observed to vary with different material textures and no underlying mechanisms have been able to explain these variations to date. This lack of physical understanding could limit the applicability of the induced polarization method to characterize the critical zone especially when immiscible fluid phases are present. To tackle this, we developed a milli‐fluidic pore model that allows investigating the saturation exponents while monitoring the pore‐scale fluid distributions. Together with numerical simulations for ideal fluid distribution cases, we found a relationship between the saturation exponents and a microscopic pore parameter called "change rate of the pore water connectivity with saturation." These findings suggest that when estimating subsurface water saturation from electrical parameters, taking the pore fluid distribution into account can significantly improve the estimation accuracy, therefore enhancing the efficiency of geo‐electrical applications for a better characterization of hydrocarbon contaminated aquifers and oil reservoirs. Key Points: A micromodel setup allows for simultaneous pore fluid visualization and complex electrical conductivity measurementThe two saturation exponents for the in‐phase and quadrature conductivities are correlated with the ganglia size of the insulating phaseA power‐law‐type relationship between the saturation exponents and the change rate of water connectivity with saturation is demonstrated [ABSTRACT FROM AUTHOR]

Phycocyanin is an interesting alternative to synthetic food colorants. Various methods to obtain phycocyanin from Arthrospira (Spirulina) biomass have been described in the literature, including ultrasonication, glass bead extraction and freeze-thawing. In this study, three optimized procedures were implemented to assess their efficacy in obtaining phycocyanin from Arthrospira maxima biomass, facilitating a comparative analysis of their effectiveness. After harvesting the biomass, extraction processes were conducted utilizing ultrasonication followed by flocculation with chitosan in various organic acid solutions, as well as glass bead extraction and freeze-thawing techniques, each followed by centrifugation. The obtained extracts were analyzed spectrophotometrically across the wavelength range of 280 to 800 nm. The freeze-thawing method yielded the highest C-PC contents at 17.03 ± 0.53%, followed closely by the ultrasonication method at 15.21 ± 0.41%. The highest purity of 2.02 ± 0.01 was attained through ultrasonication and subsequent flocculation with chitosan in acetic acid. Conversely, employing chitosan dissolved in citric or lactic acid for flocculation resulted in greenish extracts containing high amounts of chlorophyll. [ABSTRACT FROM AUTHOR]

Unconsolidated porous media are distinct from consolidated porous rocks in the negligible bulk and shear moduli. This paper is motivated by resolving the control mechanism of P-wave attenuation in the media (represented by Toyoura sands and glass beads) saturated with water. The first model is Biot theory in which longitudinal friction (arising from velocity difference between the two phases) is quantified using dynamic permeability as a function of frequency. The first model simulates phase velocity (Vp) and the ultrasonically measured quality factor (Qp) well. A second model is the transverse squirt model in which squirt is induced by pressure differential between contact of grains (COG) and the main pore space. The second model outputs unrealistic Vp and Qp. The results reveal that P-wave attenuation in unconsolidated porous media (saturated with water) is governed by longitudinal friction rather than intrapore squirt. Remarkably, low-frequency dynamic permeability is much smaller than Darcy permeability, indicating that ultrasonic P-wave is surprisingly capable of indirectly detecting the very narrow gap at COG. [ABSTRACT FROM AUTHOR]

The applicability of a fluidically heated spinning disk apparatus (SDA) was tested for investigating the influence of the tangential velocity on the deposition of particulate material systems, in particular on latex particles. First, the SDA was characterized for particle fouling investigations with micro glass beads as a model system, then, a first series of tests was carried out with a real material system, a vinyl acetate/Versa 10 copolymer. Experiments were performed for a duration of 1 h and a tangential velocity up to 0.3 m s−1. The fouling process was characterized by the local fouling layer thickness and the calculated local mass‐based fouling resistance. A decrease in fouling resistance along the radius of the rotating disk as a function of the tangential velocity was observed. [ABSTRACT FROM AUTHOR]

Written sources indicate that Alexandria in Egypt was a leading producer of Roman glass. Furthermore, archaeological finds have provided evidence for the local production of drawn glass and gold‐in‐glass beads, which were distributed throughout the world. In this study, we present an analysis of the chemical composition of more than two hundred glass objects from the Roman (2nd–3rd/4th century ce) and Late Antique (4th/5th–7th century ce) glass bead workshops located at Kom el‐Dikka in Alexandria. This study is based on the results of portable X‐ray fluorescence (pXRF) analyses carried out on raw glass, bead semi‐products, products and waste from both periods. Additionally, the glass chemistry of some Islamic (8th–12th century ce) beads found at the site has been analysed.Despite the limitations of the method, the vast majority of samples exhibited compositions confirming their general dating and Egyptian origin. Remarkably, a single bead was made of high‐alumina glass and appeared to be an import from India, possibly a remnant of the Indo‐Pacific glass bead route that connected Red Sea ports and Europe in Late Antiquity. In addition, we offer a new analytical approach to the method that has potential to enhance the value of pXRF in the analysis of archaeological glass. [ABSTRACT FROM AUTHOR]

Based on 3D printing technology, this paper investigates the effects of the printing process and reinforcement materials on the performance of 3D-printed glass bead insulation mortar. In order to improve and enhance the performance of the mortar, two sets of tests were designed for research and analysis. Firstly, by changing the direction of the interlayer printing strips, the anisotropy of the specimens in different paths was analyzed, and then the effect of different dosages of different fibers on the performance of 3D-printed glass bead insulation mortar was investigated by adding reinforcing materials. The results show that the path a specimen in the X direction's compressive strength is the best; in the Y direction, flexural strength is the best; the path b specimen in the Y direction's compressive strength is the best; in the Z direction, flexural strength is the best, but the compressive and flexural strengths are lower than the strength of the specimen without 3D printing (cast-in-place specimen); and adding reinforcing materials mortar not only has high strength but also has good printability and excellent thermal insulation. This paper provides a theoretical basis and reference value for the popularization and application of 3D printing thermal insulation mortar technology. [ABSTRACT FROM AUTHOR]

• Glass from Bilsk is chemically close to coeval materials from the Mediterranean. • At least two primary sources of glass were distinguished. • Faience beads feature peculiar composition of the vitreous phase. • Intense exchange of the local population with distant localities confirmed. The Bilsk archaeological complex comprises the remains of many structures associated with an impressive Iron Age fortified site and extends over a vast area in central-east Ukraine. Its importance is marked by the presence of apparently imported objects, including some vitreous ones (represented mainly by glass and faience beads), which provide researchers with materials for studying past trade in the area. A representative set of vitreous fragments was subjected to an analytical study with several instrumental techniques (namely: scanning electron microscopy coupled with energy dispersive spectrometry, laser ablation inductively coupled plasma mass spectrometry, micro-Raman spectroscopy and micro-X-ray diffraction) in order to characterise the beads on compositional basis. The complementary data from different techniques revealed a complex picture for the raw materials, identifying several sources of silica and, consequently, several production centres for the items included in the analysed set. This information in turn led to a better understanding of the trade networks that operated in the region between the 7th and 4th century BCE. Colouring and opacifying agents are also discussed. [ABSTRACT FROM AUTHOR]

In this work we present a novel, experimentally efficient set-up for performing non-contacting laser vibrometry on geologic materials and their analogues. We show it is possible to acoustically monitor a granular material experiment in real time compared to the typical timescale of analogue modelling experiments. We acquire non-contacting waveform data with consistently high signal-to-noise ratio. Compared to previously used standard contacting transducers, the novel joint use of sources and receivers that are both laser-based resulted in measured signals with improved waveforms and temporal bandwidths. These data acquisition improvements, in our case where surface waves are prominent in the data, enable enhanced multichannel surface wave processing, for example, in terms of reliable dispersion curve estimates. We find, given the high waveform fidelity of our acquisition system, that the observed surface waves are highly sensitive to relatively small changes in the medium's elastic properties, making them a demonstrably reliable to monitor any processes that affect elasticity in these models in near real time. As a demonstration, we continuously monitor a scaled analogue model containing granular glass beads. By continuously monitoring—that is, performing repeatable active-source acousto-seismic surveys at short time-lapse intervals—over a period of 10 hr, we find that an increase of relative humidity of 10 per cent can lead to as much as a factor of two increase in surface wave group velocities. Finally, we discuss future applications of the developed method by considering surface wave inversion for fault and stress monitoring during the deformation of a model. [ABSTRACT FROM AUTHOR]

The focus of this study is the experimental characterization of cemented granular materials, with the aim of identifying the microscopic properties of the solid bonds and describing the extension to macroscopic mechanical strength of cemented samples. We chose to use artificially bonded granular materials, made of glass beads connected by solid paraffin bridges. The results of several sets of laboratory tests at different scales are presented and discussed. Micromechanical tests investigate the yield strength of single solid bonds between particles under traction, shearing, bending and torsion loading, as a function of variations in particle size, surface texture and binder content. Macro-scale tensile tests on cemented samples explore then the scale transition, including influence of confining walls through homothetic variations of the sample size. Despite the large statistical dispersion of the results, it was possible to derive and validate experimentally an analytical expression for micro tensile yield force as a function of the binder content, coordination number and grain diameter. In view of the data, an adhesive bond strength at the contact between bead and solid bond is deduced with very good accuracy and it is even reasonable to assume that the other threshold values (shear force, bending and torsion moments) are simply proportional to the tensile yield, thus providing a comprehensive 3D model of cemented bond. However, the considerable dispersion of the data at the sample scale prevents validation of the extended model for macroscopic yield stress. A final discussion examines the various factors that may explain intrinsic variability. By comparison with other more realistic systems studied in the literature in the context of bio-cementation, our artificial material nevertheless appears suitable for representing a cemented granular material. Being easy to implement, it could thus enable the calibration of discrete cohesion models for simulation of practical applications. [ABSTRACT FROM AUTHOR]

BACKGROUND: Commercially available oral rinses contain active ingredients with concentration that is claimed by manufacturers to be effective as antiplaque agent. To date there has been no mention of the effect of oral rinse on the adherence of early plaque colonizers in plaque formation and the concentration to be used before/after meals. OBJECTIVE: The chief aim of the study was to evaluate microbial retention on the salivary pellicle on treatment with oral rinses (CHX & EO)/PS (mimicking after meals use of mouth wash/PS). METHODS: Noordini's Artifical Mouth model was used for developing the single species biofilm with early microbial colonizers of oral biofilm (A. viscosus, Strep. mitis and Strep. sanguinis respectively). The microbial retention on use of oral rinses comprising of CHX and EO as an active ingredients respectively was compared with Curcumin PS. For evaluating the microbial retention, the pellicle with microbial inoculation was developed on the glass beads in the mouth model. Subsequently the respective single specie biofilm was exposed to the mouth wash and PS after inoculation. It mimicked as use of mouth wash/PS after meals. The bacterial count in the dental biofilm was evaluated on serial dilution (CFU/ml). Sterile deionized water was used as a negative control. For qualitative analysis, Scanning electron microscope (SEM) was used to evaluate the microbial count. RESULTS: From the data it was observed that for the treatment of single species experimental biofilm with commercially available mouth rinses (CHX & EO) and PS (curcumin), there was significant retention for S.mitis, S.sanguinis and A.viscosus. There was no significant difference observed between PS and CHX treated single species biofilm. Whereas a significant difference was observed between EO treated biofilms and CHX/PS treated biofilms (p ⩽ 0.05). CONCLUSION: It can be concluded from the results that curcumin PS and CHX should not be used after meals whereas EO containing mouth rinse can be used to maintain the oral mocroflora. [ABSTRACT FROM AUTHOR]

A lightweight and high-strength water-soluble core mold for composites was prepared by hot-air drying method using aqueous solution of polyvinylpyrrolidone as the adhesive and hollow glass beads, gypsum and graphite as the matrix materials. The effects of adhesive content and matrix material on the mechanical properties and dissolution rates of the water-soluble core mold were investigated. The effect of modification methods on the mechanical properties of water-soluble core molds was investigated, and the microscopic morphology of the modified water-soluble core mold was observed by scanning electron microscopy (SEM), and its modification mechanism was initially explored. The results shows that the density of water-soluble core mold is 0.46~0.58 g/cm³, and the high-temperature treatment and the compounding of glass beads with different scales of particle size are the effective means of modification. The flexural strength of the water-soluble core can reach 7.46 MPa, the compression strength reaches 7.45 MPa, and the dissolution rate is 1.11 g/min before the modification, while the flexural strength of the modified core mold can reach 13.21 MPa, the compression strength reaches 13.45 MPa, and the dissolution rate is 6.34 g/min. The comprehensive performance of the water-soluble core mold can meet the requirements of the composite molding process, and it provides a solution for the integrated molding of the hollow profiled composites. [ABSTRACT FROM AUTHOR]

This study explores the influence of flow velocity, sphere size, and inter-sphere distance on hydrodynamics and mass transfer in a photocatalytic reactor. The effects of two different light configurations on light distribution and degradation were also evaluated. A 2D computational fluid dynamics (CFD) model was developed to simulate the continuous flow photocatalytic reactor with TiO2-coated spheres and validated with experimental measurements by observing the degradation of methyl orange. The experimental setup consists of a tube containing an equal number of TiO2-coated glass spheres. The case with radiation from one wall shows a non-uniform light distribution compared with the case with radiation from both walls. The CFD simulations focused on analyzing the velocity streamlines and turbulence characteristics (turbulent kinetic energy (TKE) and turbulence dissipation rate (TDR)). These parameters showed significant variations in each studied case. The case with larger spheres reached the highest velocity of 38 m/s of the pollutant solution. The highest TKE and TDR values of 0.47 m2/s2 and 12.2 m2/s2, respectively, were also observed in the same case, indicating enhanced mixing and mass transfer to the catalyst surfaces, ultimately leading to a more efficient degradation process. The results show that an optimized design of photocatalytic reactors can significantly improve mass transfer and, thus, degradation efficiency. [ABSTRACT FROM AUTHOR]

• Infiltration rates under low gravities were agreed with 1G based predictions. • The air entrapped little in fine porous media may have prevented the infiltration rate reduction. • The infiltration theory is applicable to fine uniform porous media under low gravities. The applicability of the theory of water infiltration in porous media under low gravities is controversial. We evaluated the hypothesis that infiltration under low gravities can be simulated from horizontal infiltration experiments under 1G. Parabolic flights provided low gravity conditions, assuming in the space station (µG), on the moon (0.19 G), and Mars (0.38 G). We measured infiltration rates in uniform particle-size porous media. No significant differences existed between infiltration rates under low gravities and ground-based predictions, i.e. the 1G condition. The air was entrapped little in this study, which may have prevented the infiltration rate reduction reported in previous studies. We concluded that the current infiltration theory adequately simulated water infiltration in fine uniform porous media under low gravity conditions. [ABSTRACT FROM AUTHOR]

Soil arching is a common phenomenon existing in the earth structures such as pile-supported embankments and buried pipes. Suffusion would be triggered in these structures during flood events after rainstorms and pipe ruptures, which poses significant threats to these infrastructures. A novel trapdoor-suffusion apparatus was developed in this study to investigate the initiation and progressive development of suffusion in infrastructures involving soil arching. A series of laboratory tests were conducted using gap-graded glass beads with an initial fine particle content of 15% by mass. Initial soil arching was established via trapdoor movement and then was subjected to a horizontal seepage flow with an increasing hydraulic gradient to induce suffusion in the arched soil. The presence of soil arching increased the susceptibility of local instability of the soil specimen within the stress reduction areas at significantly low local hydraulic gradients, due to the reduced stress restriction on fine particles. Subsequently, global suffusion was triggered at a critical hydraulic gradient much lower than the predicted value by the modified zero effective stress principle, and this critical hydraulic gradient decreased rapidly with the reduction of initial soil arching ratio (SAR). This study obtained an empirical formula in the form of power functions to characterize the variation of critical hydraulic gradient with the initial soil arching ratio. As the suffusion continued, the degradation of soil arching intensified under the low initial SAR, and became the dominant factor increasing the surface displacement of the soil. This paper reveals the increased risk of suffusion to earth structures with the presence of soil arching, and provides valuable guidance for the design and protection of earth structures against suffusion-induced challenges. [ABSTRACT FROM AUTHOR]

Microbially induced carbonate precipitation (MICP) is a potential method for ground improvement. It can enhance the physical and mechanical properties of soils through soil particle cementation and pore filling. However, the excessive number of injections of cementing solution required for MICP is a major limitation for practical engineering application. To reduce the number of injections and improve the efficiency of the cementing process, an enhancement method was investigated in this study in which an aluminum ion flocculant (AIF) was added to the cementing solution. It can enhance the curing rate and effect of MICP. Experiments were carried out on MICP-treated sand columns, MICP-treated glass beads and aqueous solutions, and the influence of AIF on the production of calcium carbonate and unconfined compressive strength (UCS) was studied. The effect of AIF on the composition and morphology of the deposited calcium carbonate was evaluated from SEM micrographs and other microscopic observations. The results of the study showed that the addition of AIF to the cementing solution significantly reduced the number of injections required and increased the UCS of the reinforcement compared to those of a control group without adding AIF. The proposed method resulted in the experimental sand column being reinforced after 3 treatments of the cementing solution with an UCS of 323.3 kPa. The UCS reaches 1692 kPa after 5 treatments of the cementing solution, compared to 9 treatments using the conventional method. The UCS was 3.2–12.7 times higher than that of the control group for the same calcium carbonate content. [ABSTRACT FROM AUTHOR]

Next to pottery, items of adornment comprise the most abundant material excavated in Northeast Africa, often being the only evidence for long-distance interactions. Interdisciplinary research has been developed to demonstrate that beads, particularly those of Indian origin from port sites on the Red Sea coast of Egypt, may attest to intense relations between North Africa and Asia. Parallels and provenance examination of recent bead and jewellery finds (four silver and coral earrings, eight silver rings and about eleven ivory bangles) from two Late Antiquity tombs of the fourth/fifth centuries AD at Berenike also suggest links between the Red Sea coast and the Nubian Nile Valley. Additionally, these ornaments raise questions as to their function in multiple burials. It is not possible to determine whether they were used as part of the funerary ritual or as offerings to the individuals buried, but several observations can be offered. [ABSTRACT FROM AUTHOR]

This study investigates the impact of mechanical alteration on resin composite surfaces and its subsequent effect on repair bond strength. A total of 100 resin composite disks were prepared and were allocated for 24 h or 1 year of artificial aging. Specimens were embedded in epoxy resin, and the composite surfaces were mechanically altered using either diamond burs or air abrasion with aluminum oxide or glass beads. A universal bonding material was applied and a 2 mm circular and 3 mm high repair composite cylinder were prepared using a Teflon mold. Then, the specimens were tested for their shear bond strength, and the de-bonded specimens were observed under a scanning electron microscope to determine the failure pattern. SPSS 26.0 statistical software was used to analyze the data. Two-way ANOVA showed a statistically significant effect of mechanical alteration and aging on the shear bond strength of S-PRG-filler-based resin composite (p < 0.05). Surface modification with a fine diamond bur showed a significantly higher bond strength in both 24-h- and 1-year-aged specimens. Surface modification with alumina significantly increased the bond strength of 1-year-aged specimens; however, it was statistically insignificant for 24 h-aged specimens. Mechanical alteration with a fine diamond bur and 50-micron alumina can improve the repair bond strength of the composite. [ABSTRACT FROM AUTHOR]

A commercial lipase from Rhizopus japonicus was activated and utilized for triglyceride (TG) modification for producing structured lipids via acidolysis of TGs and fatty acids. To activate the lipase, lipase powder was mixed with glass beads (GBs) in 1-dodecanol and then a buffer solution were added dropwise to form hydrated lipase aggregates. After removal of liquid phase in the mixuture, the residue consisting of hydrated lipases and GBs was lyophilized and then the hydration – aggregation-pretreated lipase loaded onto GBs was recovered. The acidolytic activity of the lipase was significantly enhanced after hydration – aggregation pretreatment, whereas untreated lipase exhibited little activity. The effects of the surface hydrophobicity, diameter, and amount of lipase loading on GBs on the acidolytic activity of the lipase were investigated. The optimal GBs and lipase loadings were 0.428 mm in diameter with a hydrophobic surface and 89.2 U/g-GB, respectively. Under these conditions, the lipase exhibited an 8-fold higher catalytic activity than that of the hydration – aggregation-pretreated lipase without GBs. Furthermore, continuous modification of olive oil with palmitic acid via acidolysis using the hydration – aggregation-pretreated lipase packed in a column reactor was achieved for 116 h. The half-life of the packed-bed reactor was 149 h. [Display omitted] ● Lyophilizing lipase aggregates with glass beads enhanced acidolytic activity. ● Activated lipase can modify olive oil with palmitic acid via acidolysis. ● A packed bed reactor was developed using the activated lipases. ● Water content affected activity and stability of lipase during continuous run. [ABSTRACT FROM AUTHOR]

Visualising fluid flow in porous media using optical techniques is challenging due to the inability to see through the medium. Here, we present an experimental methodology based on shadowgraphy to investigate the dynamic spreading of convective plumes in saturated transparent porous media made of glass beads. The saturated porous medium can be tuned transparent by matching the refractive index of the solid glass beads to that of the saturating fluid mixture. The proposed technique allows to investigate the essential elements of convective mixing within a porous medium using miscible fluids. We also describe a method to determine the velocity of convective plumes as they propagate. Our experimental results show that the density difference achieved during convection significantly affects the convective front velocity of the plumes. This is significant because it allows to quantitatively predict the intensity of convective mixing in porous media from the speed of the convective front. Article Highlights: Shadowgraphy has been successfully used to investigate fluid flow in transparent porous media. Convective front velocities are used to evaluate quantitatively convective mixing in porous media. In the fluid flow regime of our experiment, we observed a super-linear scaling of the convective front velocity and density difference. [ABSTRACT FROM AUTHOR]

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At present, syntactic foam composites (HGB/EP) made of epoxy resin (EP) and hollow glass beads (HGBs) have received extensive attention in the research field of lightweight materials because of their high compression strength‐to‐density ratio. However, the deep‐sea environment has put forward higher requirements for the compressive properties of materials. The traditional sandwich structure with HGB/EP as the core has gradually failed to meet the requirements for the mechanical properties of equipment deeper in the ocean. This paper proposes a sandwich structure comprising a pure EP H‐shaped structural component as the rigid skeleton and an HGB/EP syntactic foam composite as the lightweight filling component. The pure EP H‐shaped structural component was subjected to flame treatment using a butane flame jet at different distances. The compression resistance of the resulting sandwich structure was tested, and the results showed varying degrees of improvement in compressive strength after flame treatment. The effects of flame treatment on the surface adhesion performance of the pure EP were characterized using compression‐shear tests, optical microscopy, contact angle tests, infrared spectroscopy, and flame temperature tests. The results demonstrated that flame treatment at a distance of 0 cm significantly increased the oxygen‐containing functional groups on the surface of the pure EP, improved the wettability of the pure EP surface, increased the adhesive strength between the pure EP H‐shaped structural component and HGB/EP, and enhanced the compressive strength of the sandwich structure. The shear strength of the shear test specimens improved by 33.0%, while the compressive strength of the sandwich structure specimens increased by 17.5%. Highlights: The sandwich structure composed of pure epoxy resin H‐shaped structure and foam composite material was prepared.The distance of flame treatment affects the surface chemical groups of epoxy resin.Flame treatment significantly improved the surface wettability of epoxy resin. [ABSTRACT FROM AUTHOR]

Solid–liquid two-phase centrifugal pumps are important fluid transport components in production and life. Most of the studies about the influence of solid-phase parameters on fluid transport mostly focus on single-component solid particles. In this work, two kinds of glass beads with particle sizes of 2 mm and 0.4 mm were used to study the effect of the binary mixed particle volume concentration on the internal flow and wear characteristics of a centrifugal pump. The flow distribution of the binary mixed particles in a centrifugal pump and the interactions between the particles and flow components at different volume concentrations (Cv = 5%, Cv = 7.5%, Cv = 10%, Cv = 12.5%, Cv = 15%) were studied using a Computational Fluid Dynamics-Discrete Element Method (CFD-DEM). The research results show that with the increase in particle volume concentration, the head and efficiency of the pump decrease. Additionally, the distributions of the particles with different concentrations in the impeller flow passage were obtained. Moreover, the coupling force of the flow field acting on the particles decreases with the increase in particle concentration and the time it takes to convey small particles decreases with the increase in concentration, while that of large particles decreases first and then increases. Furthermore, the contact force between the particles and the blade changes periodically with time, and the wear of the centrifugal pump is mainly concentrated on the pressure surface of the blade and the wall of the volute outlet side; the wear rate increases as the particle concentration increases. [ABSTRACT FROM AUTHOR]

The cell‐free supernatant (CFS) of the biosurfactant (BS) producing pure strain of Planococcus maritimus SAMP MCC 3013 was used for enhanced oil recovery (EOR). An indigenous marine culture of P. maritimus was grown in mineral salt medium (MSM) supplemented with glucose (1%) (w/v) (30°C, 120 rpm, 7 days). CFS was used to demonstrate its application for oil recovery through three assays: pumice stone, saturated gravel, and the glass beads‐packed column. The recovery of light paraffin oil was ∼40% in the pumice stone assay and ∼43% in the oil‐saturated gravel assay, respectively. The glass bead column demonstrated ∼42% of additional 2T engine oil recovery by CFS. Our study showed that BS containing CFS from P. maritimus SAMP MCC 3013 has the ability to recover oil in its crude form without using any sophisticated purification techniques. All three methods operated by us are harmonizing with each other with respect to the findings. Those methods can be employed in large scale operations for the bio‐recovery of oils using an environmentally friendly approach through the functional properties of BS. This is most likely the first report describing the use of a glass bead pack column for EOR applications particularly from Planococcus sp. These results are symbolic of prospective applications of BS containing CFS from indigenous P. maritimus SAMP MCC 3013 under ex‐situ conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] Lunar materials are overall more reducing compared with their terrestrial counterparts, but the mechanism remains to be elucidated. In this study, we present a possible explanation for the changes in redox state of the lunar regolith caused by impact events, based on our investigations of the impact glass beads from Chang'e-5 mission. These glass beads contain iron metal grains and show concentration gradients of FeO and K 2 O (with or without Na 2 O) from their rims to centers. The compositional profiles exhibit error-function-like shapes, which indicates a diffusion-limited mechanism. Our numerical modeling results suggest that the iron metal grains on the surface of the glass beads were generated through the reduction of FeO by elemental K and (or) Na produced during the impact events. Meanwhile, the iron metal grains inside the bead may have formed due to oxygen diffusion driven by redox potential gradients. Furthermore, our study suggests that impact processes intensify the local reducing conditions, as evidenced by the presence of calcium sulfide particles within troilite grains that coexist with iron metal grains on the surface of the glass beads. This study provides insights into the oxygen diffusion kinetics during the formation of iron metal spherules and sheds light on the changes in redox conditions of lunar materials caused by impact events. [ABSTRACT FROM AUTHOR]

Mycotoxin production by aflatoxin B1 (AFB1) -producing Aspergillus flavus Zt41 and sterigmatocystin (ST) -hyperproducer Aspergillus creber 2663 mold strains on corn and rice starch, both of high purity and nearly identical amylose-amylopectin composition, as the only source of carbon, was studied. Scanning electron microscopy revealed average starch particle sizes of 4.54 ± 0.635 µm and 10.9 ± 2.78 µm, corresponding to surface area to volume ratios of 127 1/µm for rice starch and 0.49 1/µm for corn starch. Thus, a 2.5-fold difference in particle size correlated to a larger, 259-fold difference in surface area. To allow starch, a water-absorbing powder, to be used as a sole food source for Aspergillus strains, a special glass bead system was applied. AFB1 production of A. flavus Zt41 was determined to be 437.6 ± 128.4 ng/g and 90.0 ± 44.8 ng/g on rice and corn starch, respectively, while corresponding ST production levels by A. creber 2663 were 72.8 ± 10.0 µg/g and 26.8 ± 11.6 µg/g, indicating 3–fivefold higher mycotoxin levels on rice starch than on corn starch as sole carbon and energy sources. Key points: • A glass bead system ensuring the flow of air when studying powders was developed. • AFB1 and ST production of A. flavus and A. creber on rice and corn starches were studied. • 3–fivefold higher mycotoxin levels on rice starch than on corn starch were detected. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Glass was introduced as an additive to filaments used for the manufacturing of composite materials, employed by Additive Manufacturing applications. Glass accounts for a large waste electric and electronic equipment (WEEE) percentage, and its recovery and recycling can lead to the production of sustainable composite materials. In this work, poly(lactic acid) (PLA)/commercially available silicon oxide composite filaments were manufactured and their structural, thermal, rheological, and mechanical properties were assessed. Scanning Electron Microscopy confirmed the 1:2 ratio of silicon: oxygen, along with the relatively low adhesion between the filler and the matrix. Differential Scanning Calorimetry presented steady glass transition and melting temperatures of composites, whereas a crystallization temperature of 10% wt. and a crystallinity of 15% wt. composite slightly increased. Rheological analysis showcased that the viscosity of the composite filaments decreased compared to PLA (10–100 compared to 300–400 Pa·s), with a more shear-thinning behavior. Dynamic mechanical analysis exhibited increased elastic, flexural moduli, and flexural strength of composites (up to 16, 23, and 11%, respectively), whereas tensile strength and elongation decreased. The affordability of raw materials (with the future introduction of recycled ones) and the minimal processing steps can lead to the potential scaling up of the study. [ABSTRACT FROM AUTHOR]

Featured Application: White water-based paints with high-volume solids and well-graded glass beads, characterized by uniformity and curvature coefficients, improve pavement marking service life. 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. [ABSTRACT FROM AUTHOR]

Polymeric 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. [ABSTRACT FROM AUTHOR]

Glass fiber-reinforced cement-based material incorporating hollow glass beads (GFRC-HGB) is an innovative lightweight building material with exceptional energy-saving properties. Based on the framework of variational asymptotic homogenization theory, a micromechanical model is developed for predicting the effective elastic properties and recovering the local fields of unidirectional GFRC-HGB. This model starts with expressing the displacements of the heterogeneous GFRC-HGB in terms of those of the corresponding homogeneous material and fluctuation function. Then, the principle of minimum potential energy is used along with variation asymptotic method to formulate the governing variational statement for the micromechanics model, the micromechanical model is used to quantitatively investigate the influence of internal structural parameters of HGB on the elastic properties of unidirectional GFRC-HGB. The numerical results demonstrate the effectiveness and accuracy of the micromechanical model in predicting the effective elastic modulus and local fields. The numerical simulation and SEM images of the tensile fracture prove that the local stress distributions are closely related to the loading direction, and the transverse deformation is restrained by glass fibers. [ABSTRACT FROM AUTHOR]

Soil particles possess highly complex particle morphology, including particle shape and surface roughness, which have a significant impact on mechanical responses of granular materials, such as packing characteristics, small-strain stiffness and stress–strain responses. However, there has been little or no quantitative investigation on the combined effect of particle shape and surface roughness. This contribution carries out triaxial compression tests using six differently shaped granular materials under dry and drained conditions. Meanwhile, the surface texture is carefully treated to vary the degree of surface roughness for each material. Samples are prepared under a similar initial void ratio (e0) or relative density (Dr0) to eliminate the density-dependency. Samples prepared under the same sample preparation method with a given tapping number (Nt) during the sample preparation process are also considered. The experimental results show that more irregular materials tend to show greater values of deviator stresses at the peak state (qpeak) and an axial strain of 15% ( q ε a = 15 % ), and display a more gradual development of stress and a later appearance of qpeak. Except for clumped glass beads, increasing surface roughness leads to an increase in stress levels during shearing, which is more marked in irregular materials. In addition, materials with more spherical shapes or rougher surfaces demonstrate an earlier phase transformation point (εa,ptp) and an earlier occurrence of peak stress (εa,peak). [ABSTRACT FROM AUTHOR]

A unique setup for a granular vibration pumping system was developed to ease the installation into a wide variety of granular handling processes and provide flexible options for granular physics research. Although the granular vibration pumping system can notably lift granular materials with an oscillating pipe, the climbing mechanism and related granular physics are yet to be clarified thoroughly. The new setup employs an eccentric cam mechanism as the excitation source, a linear system with dust tolerance, and a recording system, making it simple, compact, and adaptable for extending experiments. The excitation mechanism generated a clear sinusoidal vibration in the pipe, realizing better reproducibility of the climbing motions of glass beads. Moreover, the compact design facilitates the close placement of multiple pipes vibrating individually, which affects the transport performance. In addition, various types of sample cells that store particles and the imaging system allow for the detailed observation of particle motions in the pipes and even the sample cells. This developed system provides easy and accurate tuning of the existing parameters of the granular vibration pumping system, as well as new options for a further understanding of granular physics. [ABSTRACT FROM AUTHOR]

This study focused on two familiar items in our daily lives: grains and boiling water. Accurately measuring boiling dense granular beds requires specialized instruments and novel techniques. An annular vertical riser was used to boil granular films. The riser was filled with glass beads and then immersed in liquid water. The water is heated by inducing eddy currents at the base of the riser, which is composed of carbon steel. Beyond the critical electric current, Ic, the Lyapunov exponent of the time series of the measured temperature distributions within the granular films became positive. This indicates the chaotic behavior of the films. Slightly above Ic, patterned instabilities with affine fractal-like structures were observed in the boiling granular films. Chaotic boiling granular films manifested percolation and transition to turbulence. Computer simulations of the above system under the guidance of generative AI (GenAI) successfully reproduced many critical features of the experimental observations, which can be considered a significant breakthrough in the modeling and simulation of complex systems. With this success in utilizing GenAI, more accurate instruments can be developed, resulting in the world of tomorrow rapidly becoming today's world. [ABSTRACT FROM AUTHOR]

Biocementation has broad application prospects for reinforcing granular materials in geotechnical engineering. However, only few studies have been conducted on the size effect in biocemented granular materials, despite the recognition of the size effect in the uncemented ones. In this study, a series of tests on Brazilian tensile strengths were carried out for biocemented sand, focusing on the size effect. Glass bead sand (GBS) and calcareous sand (CCS) of five different particle sizes were adopted at two different biocementation levels. Under otherwise identical conditions, the tensile strengths of biocemented CCS specimens were higher than that of the biocemented GBS specimens. The tensile strengths of the biocemented specimens decreased with an increase in particle size, which can be captured by a power function, inspired by the size–effect relation. The novel findings of this study can provide the size–effect function for the establishment of constitutive models and the data basis for the validation of numerical models when theoretical models are necessary in predictions of deformation and failure for field-scale biotreated soils. [ABSTRACT FROM AUTHOR]

The paper analyzed the economic transporting performance of k-epsilon turbulence models using the Eulerian two-fluid approach in transporting highly concentrated fine particulate slurry through horizontal pipelines using Kaushal et al. (2005) experimental data of glass beads slurry of 125 μm mean diameter for volumetric concentration ranging 30%–52% and flow velocity ranging 2–5 m/s. The primary components of economical slurry transport are Specific Energy consumption (SEC) and pressure drop; both have been examined in the performance of different κ-ϵ models and are yet to be unlighted on these parameters. The CFD model found the excellent performance of all k-epsilon models with slightly more effectiveness in the case of the Realizable κ-ϵ model. The analyzed and validated CFD model was subsequently used in examining the parameters of slurry flow, such as the secondary phase velocity, concentration distribution, and SEC analysis for the range of fine particles 125, 150, and 212 µm. The plotted contours from CFD are useful in visualizing slurry flow parameters at intermediates inlet values for slurry inlet flow velocity ranging 2–6 m/s and inlet volumetric concentration ranging 30%–55% for fine particles. Analysis revealed that the highly concentrated fine particles slurry transported at optimum volumetric concentration range of 40–45% are economical slurry transport. [ABSTRACT FROM AUTHOR]

Synchrotron X‐ray microtomography (XMT) was used to measure total air‐water interfacial areas (Aaw) as a function of water saturation (Sw) for several soils that comprise a range of physical and geochemical properties. Measurements were also conducted for glass beads and quartz sands for comparison. Apparent near‐linear Aaw‐Sw relationships are observed for the three sands and the three sandy soils. In contrast, the measured interfacial areas for two soils that contain greater proportions of silt and clay are strongly nonlinear functions of water saturation. The greater degree of nonlinearity observed for these two soils is due to their much greater particle‐size distributions (i.e., uniformity coefficients) and their concomitant greater range in pore sizes. Interfacial areas determined with the thermodynamic method were used to benchmark the XMT measurements. XMT‐measured interfacial areas compare well to the thermodynamic‐determined values for the sands and sandy soils. In contrast, the XMT‐measured interfacial areas for the two soils with larger particle‐size distributions are not fully congruent with the thermodynamic‐determined values. Both of these soils have large fractions of pore space comprising nominal pore diameters smaller than the resolution of the XMT imaging. These results suggest that air‐water interfacial area may not always be fully characterized by standard XMT for soils with large particle‐size distributions. Plain Language Summary: High‐resolution pore‐scale imaging is conducted for several sands and soils to examine the relationship between the magnitude of air‐water interfacial area and water saturation as well as to evaluate the effectiveness of the imaging method. Key Points: X‐ray microtomography (XMT) measurements of air‐water interfacial area are reported for soilsThe relationship between air‐water interfacial area and water saturation is nonlinearBenchmarking results indicate that XMT may not measure all interfacial area for soils with higher silt and clay contents [ABSTRACT FROM AUTHOR]

The glass compound eye bead is the exquisite embodiment of the glassmaking technology of ancient craftsmen, and is an example of the cultural exchange between China and the West during the Warring States Period. This study takes two dots and mesh beads with seriously weathered surfaces excavated from Hejia village, Zhouling as the research object. Micromorphology, X-ray fluorescence spectroscopy (XRF), microscopic laser Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were respectively used to determine the chemical elements, valence states and compositions of the glass matrix and its weathering products. In this study, the valence state analysis of group-d elements is used to reveal the electron transition mode and explain the colour formation reason of blue-black glass matrix. In terms of weathering products, in addition to the identification of common cerusite [PbCO3] and barite [BaSO4], the study also found the blue weathering product alforsite [Ba5(PO4)3Cl] for the first time. The study also makes reasonable assumptions about the reasons for their appearance. The X-ray photoelectron spectroscopy (XPS) used in this study has positive significance for the study of the formation mechanism of glass colour. The scientific and technological analysis data of these two glass beads provide basic data for the related research of the lead-barium glass system produced in China, and also provide a certain scientific basis for the related protection research. [ABSTRACT FROM AUTHOR]

Glass fiber‐reinforced resin matrix composites have good mechanical and impact resistance properties, while with particle co‐reinforcement, a synergistic effect can further improve their performance. In this paper, continuous glass fiber‐reinforced nylon 6 (GF/PA6) and continuous glass fiber (GF) with glass beads (GBs) co‐reinforced nylon 6 (GB–GF/PA6) were prepared to investigate the co‐reinforcement mechanism and the synergistic effect of particle and fiber. A quantitative parameter of the residual impact force divided by the critical force Pr/Pcr, as the damage degree of the low‐velocity impact, is defined to evaluate the impact resistance of the composite. The results indicate that the damage of GB–GF/PA6 was lower than that of GF/PA6, and the synergistic effect reaches the most obvious at the GB addition of 10 wt%. Scanning electron microscope (SEM) and x‐ray computed tomography (XCT) images disclose that GB impedes the type II crack spread in the matrix and fiber/matrix interface. With the type II cracks reducing, the materials' resistance to delamination can be significantly enhanced. For the composite structure, in which 10 wt% GB and 60 wt% GF are introduced, the flexural strength, shear strength, and pendulum impact strength were tested with the maximum values of 379.4 MPa, 53.1 MPa, and 219.0 J/m2, respectively. This composite structure design, presenting a continuous GF and GBs co‐reinforce effect, offers a manufacturing process that is easily scalable to achieve excellent characteristics. [ABSTRACT FROM AUTHOR]

Pockmarks are morphological depressions commonly observed in ocean and lake floors. Pockmarks form by fluid (typically gas) seepage thorough a sealing sedimentary layer, deforming and breaching the layer. The seepage‐induced sediment deformation mechanisms, and their links to the resulting pockmarks morphology, are not well understood. To bridge this gap, we conduct laboratory experiments in which gas seeps through a granular (sand) reservoir, overlaid by a (clay) seal, both submerged under water. We find that gas rises through the reservoir and accumulates at the seal base. Once sufficient gas over‐pressure is achieved, gas deforms the seal, and finally escapes via either: (a) doming of the seal followed by dome breaching via fracturing; (b) brittle faulting, delineating a plug, which is lifted by the gas seeping through the bounding faults; or (c) plastic deformation by bubbles ascending through the seal. The preferred mechanism is found to depend on the seal thickness and stiffness: in stiff seals, a transition from doming and fracturing to brittle faulting occurs as the thickness increases, whereas bubble rise is preferred in the most compliant, thickest seals. Seepage can also occur by mixed modes, such as bubbles rising in faults. Repeated seepage events suspend the sediment at the surface and create pockmarks. We present a quantitative analysis that explains the tendency for the various modes of deformation observed experimentally. Finally, we connect simple theoretical arguments with field observations, highlighting similarities and differences that bound the applicability of laboratory experiments to natural pockmarks. Plain Language Summary: Pockmarks are pit‐like depressions common in ocean and lake floors, formed by gas seepage through underlying sediments. Despite relevance to both fossil fuel exploration and global warming, the mechanisms by which pockmarks evolve remain elusive. We conduct simple laboratory experiments in which we inject air into a layer of glass beads ("reservoir") overlain by a layer of clay ("seal"), all submerged underwater in a transparent box. We find that gas rises through the sand and accumulates at the base of the clay. Then, gas pressure rises until it suffices to deform the clay and escape, forming a pockmark. This occurs by one of three mechanisms, depending on clay thickness and stiffness: (a) heaving of a dome which then fractures in thin clay layers; (b) faulting in thick, stiff clays; and (c) bubbles ascend in thick, soft clays. Pipe‐like focused gas conduits connecting the clay bottom to the pockmark are created by the rise of a "trains" of bubbles that weaken their path. These pathways can also initiate in faults. Repeated seepage events push the clay particles, suspending them in water to create a pockmark. Our findings agree with field observations, improving our understanding of natural pockmark formation. Key Points: Sandbox experiments link pockmark morphology (irregular vs. conical) to gas seepage‐induced deformation of the host (seal) layerExperiments and theory show seal thickness and consolidation control deformation mechanism: doming, brittle (faults), or plastic (bubbles)Theoretical calculations predict that under field conditions, the preferred mechanism for gas escape will be bubbles rising in faults [ABSTRACT FROM AUTHOR]

The Apollo 15 low-titanium and Apollo 17 high-titanium pyroclastic glass beads are among the most primitive magmatically derived samples obtained from the Moon. Two key samples, the low-Ti Apollo 15426 green glass clod and the high-Ti Apollo 74220 orange glass are morphologically distinct, where the Apollo 15 beads are larger (~107 μm along maximum axis) and more fractured, and the Apollo 17 are smaller (~42 μm) and less fractured. In this study, holohyaline beads as well as crystallized beads were examined from both samples using petrography, electron microprobe analysis, and laser-ablation inductively coupled plasma mass spectrometry. Crystallized beads show compositional variability in major, minor, and trace elements and enable examination of magmatic mineral fractionation processes during cooling of both deposits. The Apollo 15426 beads experienced variable olivine crystallization, whereas the Apollo 74220 beads experienced both olivine and ilmenite crystallization. Holohyaline beads from both deposits show more limited major, minor, and trace element variability than their crystallized counterparts. Trace element abundance data for individual holohyaline beads show that in Apollo 74220, they are tightly clustered at ~30× Carbonaceous Ivuna chondrite [CI] with negative Eu anomalies and subchondritic Nb/Ta, interpreted to reflect the presence of late-stage magma ocean cumulates overturned into an otherwise primitive mantle source. Incompatible trace element abundances for holohyaline beads in 15426 are supra-chondritic from ~8× CI, to >80× CI, with pronounced relative depletions in Sr and Eu for the most incompatible element enriched beads, which represent a distinct bead group within the deposit. Apollo 15426 beads have elevated Ni and Co abundances at the edges of the beads compared to their centers. These data are interpreted to reflect a more complex magmatic evolution of the 15426 deposit, beginning with (i) initial magma generation, storage, and assimilation within shallower low- and high-Ca pyroxene bearing magma ocean cumulates (15B,C); (ii) mobilization of the earlier magmas by more recently generated primitive magmas (15A); (iii) eruption and crystallization of some beads (15D,E); and (iv) later jumbling of the deposit, possible impact contamination and addition of exotic basaltic bead components (J Group). In contrast, the 74220 data show no discernable difference between Ni and Co abundances at the edges and centers supporting prior observations for limited melt fractionation and an absence of meteoritic components. Both deposits are likely to have been formed in the presence of a transient atmosphere. Using 74220 melt compositions from this study, post-entrapment crystallization abundances range from 266 to 1130 μg/g for H2O, 36 to 68 μg/g for F, 441 to 832 μg/g for S, and 0 to 2.31 μg/g for Cl, consistent with prior studies and suggesting up to ~0.1 wt % H2O in the melt, with considerably less in the source. The role that late-stage magma ocean cumulates rich in ilmenite and high-Ca pyroxene might play in modifying this volatile element estimate, however, casts remaining doubt on the volatile element abundance and evolution of the primitive Moon. [ABSTRACT FROM AUTHOR]