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It is well recognized that the liquefaction resistance is closely related to the consolidation stress in soils. However, previous studies investigated the effects of unidirectional consolidation loads rather than multi-directional consolidation loads on liquefaction resistance. In this study, two types of granular materials, spherical glass beads and irregularly-shaped sands, are tested under undrained conditions with the uni- and bi-directional loads to investigate the liquefaction resistance. The effects of consolidation loads on liquefaction resistance can be explained in terms of material anisotropy. In simple shear tests, the stress- and strain-controlled loading paths are adopted for the consolidation and the undrained shear process, respectively. The results indicate that the liquefaction resistances of both materials consolidated under the multi-directional consolidation loads are higher than those consolidated under the linear loads. More consolidation loading cycles induce a better liquefaction resistance of the specimens at a given relative density. In addition, the influence of consolidation stress on liquefaction resistance is demonstrated by the anisotropy of specimens. Cyclic vertical stress, unidirectional shear stress, and bidirectional shear stress applied during consolidation produce greater isotropy and improve the liquefaction resistance of the specimen compared with the monotonic vertical stress, and their effects align with an increasing order. [ABSTRACT FROM AUTHOR]

A machine learning-based strategy is presented to estimate the contact force chains of uniformly sized spherical granular materials under triaxial compression, using particle kinematics and inter-particle contact evolution data measured by X-ray micro-tomography (μCT). To this end, a graph neural network (GNN) is introduced to predict the contact force chains of granular materials at the end of a shear increment based on the evolution of contact network and grain displacement during that shear increment. Meanwhile, discrete-element modelling (DEM) is performed for a glass bead specimen under triaxial compression with the use of in situ μCT scanning. The DEM model has the same initial conditions as the glass bead specimen and is validated by comparing the calculated stress–strain curves, particle kinematics and inter-particle contact fabric evolution of the numerical specimen with the experimental results. The DEM model is used to generate sufficient virtual data to train the GNN model, which is applied to the glass bead specimen to predict the evolution of contact force chains. The model-predicted results yield a power-law relationship between the above mean normalised particle maximum normal contact forces and the probability density function, which is consistent with the findings reported in previous numerical studies. [ABSTRACT FROM AUTHOR]

This document explores the impact of particle shape on the behavior of granular materials. The authors reference previous studies and present their own experimental results to evaluate the relationship between particle shape and critical state. They find that granular soils with rounded particles have lower and less steep critical state lines compared to soils with angular particles. The authors also discuss the effect of particle shape on instability triggering and highlight inconsistencies in simulation results. The study emphasizes the importance of considering particle shape in determining the mechanical behavior of granular materials. [Extracted from the article]

This study presents technologies of the triple hybrid landing gear for the OMOTENASHI(Outstanding Moon exploration Technologies demonstrated by Nano Semi-Hard Impactor) spacecraft, which consists of an airbag, a crushable material as a shock absorber, and an impact resistance structure. The inflated airbag has capability to possibly mitigate impact acceleration at the instant of landing and submergence into regolith that covers a planetary surface. The crushable material with lattice structures, manufactured by a metal 3D printer, serves a dual purpose: it dissipates kinetic energy and controls the impact acceleration at landing by compressing itself within a designed deceleration distance. Further, in the impact resistance structure, the protective object is filled with resin and hollow glass beads, and the impact resistance is improved while the weight reduction is maintained. This paper provides the technical details such as the required specification, verification test results, and assembly result of the surface probe as the smallest lander of the OMOTENASHI spacecraft. • The triple hybrid landing gear appeared for the world's smallest lunar lander. • Shock absorber, airbag, and shock-resistant structure were complementarily combined. • The shock absorber with excellent mounting capability was produced by a 3D printer. • The airbag shape was designed with the Terra-mechanics theory. • Development tests suitable for small landers were demonstrated. [ABSTRACT FROM AUTHOR]

Non-conventional machining processes are capable of achieving higher performance compared to conventional ones due to their inherent characteristics and higher amount of parameters which can be favorably regulated. Although the correlation between the most important process parameters and process outcome has been already established for a wide range of conditions and workpiece materials, the introduction of new considerations related to the three pillars of sustainability require further investigation on new means for the enhancement of AWJ milling process. As one of the most important parameters in AWJ milling is the abrasive material, the introduction of new materials may offer considerable advantages from different perspectives. Thus, in the present work, a comprehensive investigation on the efficiency of using eco-friendly, mixed abrasives is carried out under various conditions such as different traverse feed rate, abrasive mass flow rate, water jet pressure, jet impingement angle, and mixing ratio. The feasibility of using mixed abrasives is evaluated in terms of achievable depth of penetration, kerf width, kerf taper angle as well as material removal rate (MRR), and cutting efficiency. The findings indicate that among other factors, the mixing ratio plays a noticeable role especially regarding MRR and cutting efficiency and can offer an additional effective means to achieve the desired kerf characteristics in conjunction with other significant parameters such as water jet pressure. [ABSTRACT FROM AUTHOR]

Glass beads from two Islamic archaeological sites in the Tagus valley in central Spain were selected and analysed by laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS), and a subset of samples (n = 6) was analysed for Pb isotopes by multicollector thermal ionization mass spectrometry (MC‐TIMS). The analytical and isotopic data of the beads from Ciudad de Vascos (Toledo) and Albalat (Cáceres) demonstrate beyond reasonable doubt that glass beads were produced in the Iberian Peninsula during the Islamic period using local Pb‐silica and soda‐rich plant‐ash glass. The bead workshops in al‐Andalus were evidently part of an efficient system of glass collection and recycling, and used only relatively simple bead‐making techniques such as winding and folding. At present it is unclear to what extent the Islamic bead‐makers in the Iberian Peninsula were involved in the international trade in glass beads or whether their products were mainly destined for a regional market. Despite local production, some samples show compositional and typological features that suggest the import of finished glass beads, perhaps from Central Asia. [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]

Very little information exists on the particle and chemical contamination of consumer (horticultural) composts. In this study, anthropogenic microcellulosics (AMCs), microplastics (MPs) and other microscopic debris, along with anthropogenically impacted metals (Cu, Zn, Pb), have been determined in 12 composts (seven garden composts and five growbags) purchased at outlets in the UK. AMCs and MPs, determined microscopically, were present in all samples at up to about 1100 kg−1 dw. AMCs were more abundant and were dominated by fibres constructed of rayon and cotton, while petroleum-based MPs exhibited a greater diversity in shape and polymeric construction (including polyolefins, polyethylene terephthalate, polyvinyl chloride, resins, paints and rubbers). Other microdebris, present in much smaller concentrations in the composts, consisted of fragments of glass, metal and machined wood and spherical glass beads. Concentrations of the anthropogenically impacted metals, Cu, Pb and Zn, determined directly by energy-dispersive X-ray fluorescence spectrometry, were heterogeneously distributed and averaged 52.4, 192 and 51.6 mg kg−1 dw, respectively. Although concentrations of anthropogenic particles were not related to cost or type of compost, physico-chemical properties or metal concentrations, a significant relationship between Pb content and particle diversity (number of polymers and debris types) was established. This relationship might result from the general contamination of the environment by both Pb and anthropogenic particulates, or the association of the metal with various types of material (e.g. paints, polyvinyl chloride, glass). Despite the ubiquity and diversity of MPs and microdebris in consumer composts, an understanding of their impacts on plant growth, either directly or indirectly (e.g. by interacting with metals), is unknown. [ABSTRACT FROM AUTHOR]

Spherical glass beads weaken the influences of particle morphology, surface properties, and microscopic fabric on shear strength, which is significant for revealing the relationship between macroscopic particle friction mechanisms and the particle size distribution of sand. This paper explores the shear mechanical properties of glass beads with different particle size ratios under different confining pressures. It obtains the particle size ratio and fractal dimension D through an optimal mechanical response. Simultaneously, we explore the range of the fractal dimension D under well-graded conditions. The test results show that the strain-softening degree of Rs is more obvious under a highly effective confining pressure, and the strain-softening degree of Rs can reach 0.669 when the average particle size d ¯ is 0.5 mm. The changes in the normalized modulus ratio Eu/Eu50 indicate that the particle ratio and arrangement are the fundamental reasons for the different macroscopic shear behaviors of particles. The range of the peak effective internal friction angle φ is 23 °~35 °, and it first increases and then decreases with the increase in the effective confining pressure. As the average particle size increases, the peak stress ratio MFL and the peak effective internal friction angle φ first increase and then decrease, and both can be expressed using the Gaussian function. The range of the fractal dimension D for well-graded particles is 1.873 to 2.612, and the corresponding average particle size d ¯ ranges from 0.433 to 0.598. Under the optimal mechanical properties of glass beads, the particle size ratio of 0.25 mm to 0.75 mm is 23:27, and the fractal dimension D is 2.368. The study results provide a reference for exploring friction mechanics mechanisms and the optimal particle size distributions of isotropic sand. [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]

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]

It is of great significance to sort specific types of cells through a fast and efficient technology in biomedical research and clinical applications. In this study, commercial hollow glass beads were modified with 3-aminopropyltriethoxysilane (ATPES) and hyaluronic acid (HA) sequentially, which can capture HeLa cells with nearly 100% efficiency within 10min. The beads can specifically recognize and sort HeLa cells from a cell coculture of HeLa and L-929 depending on their strong buoyancy and good affinity with cancer cells. The job provides a facile, quick and low-cost cell sorting method, which has potential application in the fields of specific and efficient cell isolation. [ABSTRACT FROM AUTHOR]

The pig (Sus scrofa) is the most widely used large animal model in Europe, with cardiovascular research being one of the main areas of application.Adequate refinement of interventional studies in this field, meeting the requirements of Russell and Burch’s 3 R concept, can only be performed if blood-contacting medical devices are hemocompatible.Because most medical devices for cardiovascular interventional procedures are developed for humans, they are tested only for compatibility with human blood.The aim of this study was therefore to determine whether there are differences in behavior of human and porcine platelets from commercial hybrid pigs when they come into contact with borosilicate glass, which was used as an exemplary thrombogenic material.For this purpose, changes in platelet count, platelet volume and platelet expression of the activation markers CD61, CD62P and CD63 were measured using a modified chandler loop-system simulating the fluidic effects of the bloodflow.Commercial hybrid pig and human platelets showed significant adhesions to borosilicate glass but the commercial hybrid pigs platelets showed a significantly higher tendency to adhere to borosilicate glass.In contrast to human platelets the platelets of commercial hybrid pigs showed significant activation after 4 to 8 minutes exposure to borosilicate glass and there were differences among the ratios of surface and activation markers in between the platelets of both species. [ABSTRACT FROM AUTHOR]

The study establishes two mathematical formulations to predict the pressure drop in a solid–liquid slurry flowing through a straight pipe. Employing the Eulerian–Eulerian RNG k-ε model, the computational investigation uses water as the carrier fluid and glass beads as solid particles. The analysis spans various particle sizes (d50 = 75–175 μm), volumetric concentrations (Cvf = 10–50%), and velocities (Vm = 1–5 m/s). The first model, developed using the MATLAB curve-fitting tool, is complemented by a second empirical equation derived through non-polynomial mathematical formulation. Results from both models are validated against existing experimental and computational data, demonstrating accurate predictions for d50 = 75–175 µm particles within a Reynolds number range of 20,000 ≤ Re ≤ 320,000. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are colonized by biofilm-forming microbes. Biodegradable plastics, popular replacements for traditional plastics, still have unknown biofilm formation characteristics. We conducted a 60-day indoor experiment, where sediment was exposed to traditional MPs (polypropylene, PP), biodegradable MPs (polylactic acid, PLA), and glass beads (GLASS). The microbial communities in the MPs-biofilm were analyzed using high-throughput sequencing. Results indicated that Proteobacteria was the dominant phylum on all substrates, followed by Actinobacteria, and Firmicutes. At the genus level, the majority of microorganisms colonizing PP possessed nitrification and denitrification capabilities, while the dominant bacteria on PLA were capable of degrading lignin, cellulose and carbon metabolism. The genus Sphingomonas, a promising bacteria capable of degrading biodegradable microplastics, was particularly discovered on the PLA biofilm, meanwhile, bacterial colonization of PLA indirectly increased the potential for human transmission of pathogens. Redundancy analysis revealed that the pH and moisture significantly affected the bacterial communities. Pearson correlation heatmap indicated that the abundance of the majority of dominant bacterial genera of two MPs biofilms is negatively correlated with the physicochemical parameters of sediment (pH, moisture, TN, TP), except for salinity. The microbial communities associated with PP and PLA exhibited distinct differences caused by the combined effects of changes in physicochemical properties of sediment and different material substrates. This study provides further evidence of the significant selective features exhibited by microbial colonization on these two MPs when exposed to the same source community, offering insights into the exploration of promising bacteria for MPs degradation. [ABSTRACT FROM AUTHOR]

Perfluorooctanesulfonic (PFOS) acid is a persistent anthropogenic organic fluorinated compound ubiquitous in industrial applications and is resistant to conventional wastewater treatment methods. Human exposure to PFOS can cause adverse health effects. In this study, a low‐content titanium dioxide (TiO2) photocatalyst coated on glass beads was synthesized through a simple method and showed improved activity and durability. This material exhibited easy recovery and potential for large‐scale applications. The efficacy of the TiO2 nanoparticle‐deposited glass beads' (TiO2@GBs) photocatalyst in treating PFOS contaminants in wastewater was explored, demonstrating its ability to promote photocatalytic reactions to break down PFOS into shorter chain byproducts. The study employed the response surface method (RSM) using the Box–Behnken design (BBD) to optimize treatment conditions at a PFOS concentration of 0.1 mg/L. Investigated factors included pH (4–9), TiO2 dosage (0.11–0.53 g/L), and irradiation time (4–8 h). Design‐Expert 12 software was used to plan and optimize the experiments. Fifteen experiments were conducted, and triplicate runs occurred at the center points of the experimental plan. ANOVA and Fisher's test yielded an F value of 73.88 (p < 0.0001) which demonstrated the model's statistical significance with over 99% confidence regression prediction. The optimized treatment conditions that achieved 100% degradation of PFOS included a pH of 4.55, TiO2 dosage of 0.396 mg/L, and irradiation time of 6.59 hours. After the photocatalytic treatment, PFOS was transformed into intermediate products such as PFPeA, PFHpA, L‐PFBS, and L‐PFHxS. [ABSTRACT FROM AUTHOR]

The traditional specific storage coefficient (Ss) was defined under two assumptions. One is that aquifer rock deforms only in the vertical direction, and the other is that the average rock stress remains unchanged. Consequently, Ss is irrelevant to the shear modulus of rock (G). In this paper, the Biot theory is used to derive a new specific storage coefficient (Ss∗) with the natural deformation of rock. Ss∗ appears to be relevant to G. Compressed glass beads and Berea sandstone are used for illustration. At frequencies lower than 10 kHz, the equation of groundwater flow with Ss∗ yields the same phase velocity and quality factor as the Biot theory, and therefore, it is capable of accurately predicting fluid pressure diffusion in the low‐frequency regime. The results also show that Ss is 16%–17% higher than Ss∗. In conclusion, the latter one is superior to the former in its consistency with the Biot theory and unconstraint by the aforementioned two assumptions. [ABSTRACT FROM AUTHOR]

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]

We carried out a petrological, mineralogical, and geochemical study of fragmental and regolith breccia clasts separated from two Chang'e‐5 (CE‐5) soil samples, CE5C0000YJYX03501GP and CE5C0400, which provide an opportunity to investigate the compositional change of regolith at the landing site through time. Fragmental breccia CE‐5‐B3 contains a diverse range of basaltic clasts and basaltic mineral fragments, and some rare Mg‐suite‐like minerals. Regolith breccias CE‐5‐B006, CE‐5‐B007, CE‐5‐B010‐08, CE‐5‐B010‐09, CE‐5‐B011‐07, and CE‐5‐B016‐03 contain mare basaltic fragments, mare vitrophyric clasts, rare Mg‐rich fragments possibly derived from the Mg‐suite rocks, and impact‐derived glass spherules. Pb‐isotope data obtained for baddeleyite grains found both inside some of the basaltic clasts identified in breccia fragments and in the breccia matrices yield Pb/Pb dates similar to the 2 Ga crystallization age of the CE‐5 basalt fragments, extracted directly from the soil sample. Seventy‐four Pb isotope analyses of Ca‐phosphate grains also indicate that the majority of these grains have Pb/Pb dates of 2 Ga, suggesting that they originate from the CE‐5 basalts. In addition, a Pb–Pb isochron drawn through analyses of four Ca‐phosphates in breccia CE5‐B006 yielded an intercept corresponding to a date of 3871 ± 46 Ma, which is the best possible estimate of the formation age of these four grains. Electron probe microanalysis shows that the breccias contain components similar to CE‐5 mare basalt fragments extracted directly from the soil sample, implying that the fragmental and regolith breccia fragments are mostly composed of material sourced from the underlying basalts. The general absence of impact melt breccia clasts, along with the general lack of Fe–Ni metal and absence of added meteoritic debris all suggest that the regolith at the CE‐5 landing site is immature and dominated by material mixed together by small local impact cratering events. Trace element analyses show that the glass beads in the regolith breccias have a Th abundance of 4.06–5.28 μg g−1. This is similar to the Th content of the regolith above the Em4 unit at the landing site as measured from orbit, as well as the estimated bulk Th content of CE‐5 basalts, suggesting that Th of the local regolith is predominantly sourced from the underlying mare basalts, without significant Th addition from Th‐rich exotic clasts sourced from evolved lunar lithologies. [ABSTRACT FROM AUTHOR]

Glass beads first appear in the archaeological record of southern Africa around the mid-first millennium CE, marking the earliest signatures of extensive connections between the southern African region, the East African coast, and the broader Indian Ocean rim. Key research focused on glass beads, particularly from notable southern African polities, like the renowned Mapungubwe and Great Zimbabwe sites, has laid the groundwork for a regional taxonomic series of these beads, emphasizing their role as indicators of wealth and social status. This paper introduces new data on 59 glass beads from a recently excavated and lesser-known Zimbabwe culture site in the Mberengwa region of south-central Zimbabwe. The analysis employs non-invasive techniques, including typological classification and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The investigation identifies six glass bead series from Chumnungwa, composed of plant ash-lime (v-Na-Ca), vegetable soda-high alumina (v-Na-Al), and soda-based glasses with high-alumina concentrations (m-Na-Al). These beads, widely distributed in Asia and Africa between the eight and seventeenth centuries, shed new light on the geochemistry, provenance, and circulation patterns of glass beads in southern Africa, particularly within a community situated beyond the well-known Iron Age polities. Notably, Chumnungwa emerges as the first known Zimbabwe culture site in southern Africa to yield m-Na-Al 6 glass beads. However, as recently demonstrated at the Toutswe sites in Botswana, it is probable that other Zimbabwe culture sites in the region also possessed m-Na-Al 6 glass beads. These beads may have been misclassified as m-Na-Al 2 glass since this group was only recently unveiled on the East African coast, after the bulk of the currently available literature had been published. Insights drawn from contextual recovery data and Shona anthropology form the basis for an extended discussion on the consumption and sociality of glass beads in Iron Age southern Africa. Ultimately, the study underscores the challenge of typologically categorizing beads into established series without the application of LA-ICP-MS and other scientific approaches. [ABSTRACT FROM AUTHOR]

Mucin glycoproteins are a significant source of carbon for the gut bacteria. Various gut microbial species possess diverse hydrolytic enzymes and catabolic pathways for breaking down mucin glycans, resulting in competition for the limited nutrients within the gut environment. Adherence to mucin glycans represents a crucial strategy used by gut microbes to access nutrient reservoirs. Understanding these properties is pivotal for comprehending the survival mechanisms of bacteria in the gastrointestinal tract. However, characterization of individual strains within the vast array of coexisting bacteria in the microbiome is challenging. To investigate this, we developed mucin-immobilized particles by immobilizing porcine gastric mucin (PGM) onto glass beads chemically modified with boronic acid. These PGM-immobilized particles were then anaerobically cultured with human fecal microbiota, and the bacteria adhering to PGM were isolated. Interestingly, the microbiome composition remained largely unchanged irrespective of PGM immobilization. Nonetheless, bacteria isolated from PGM-immobilized glass particles exhibited notably higher N-acetylgalactosaminidase activity compared to the control beads. Furthermore, Bacteroides strains isolated from PGM-immobilized glass particles displayed enhanced adhesive and metabolic properties to PGM. These findings underscore the utility of PGM particles in enriching and isolating specific microbes. Moreover, they highlight substantial differences in microbial properties at the strain level. We anticipate that PGM-immobilized particles will advance culture-based microbiome research, emphasizing the significance of strain-level characterization. [ABSTRACT FROM AUTHOR]

This article discusses the discovery of bronze weights in the form of a cuboctahedron, one of the thirteen Archimedean solids, in northwestern Russia. These weights, dating back to the eighth to tenth centuries, were found near the village of Staraya Ladoga, an important historical trading center in Eastern Europe. The article explores the history of Ladoga, its role as a trading center, and the Middle Eastern origin of the cuboctahedron weights. It also discusses the dissemination of knowledge about Archimedean solids through Arabic/Persian culture and their later rediscovery in Europe. [Extracted from the article]

The gravity-induced depth-dependent elastic properties of a granular half-space result in multiple dispersive surface modes and demand the consideration of material heterogeneity in metabarrier designs to suppress surface waves. Numerous locally resonant metabarrier configurations have been proposed in the literature to suppress Rayleigh surface waves in homogeneous media, with little focus on extending the designs to a heterogeneous half-space. In this work, a metabarrier comprising partially embedded rod-like resonators to suppress the fundamental dispersive surface wave modes in heterogeneous granular media known as first order PSV (PSV1; where P is the longitudinal mode and SV is the shear-vertical mode) and second order PSV (PSV2) is proposed. The unit-cell dispersion analysis, together with an extensive frequency-domain finite element analysis, reveals preferential hybridization of the PSV1 and PSV2 modes with the longitudinal and flexural resonances of the resonators, respectively. The presence of the cutoff frequency for the longitudinal-resonance hybridized mode facilitates straightforward suppression of the PSV1 mode, while PSV2 mode suppression is possible by tailoring the hybridized flexural resonance modes. These PSV1 and PSV2 bandgaps are realized experimentally in a granular testbed comprising glass beads by embedding 3D-printed resonator rods. Also explored are novel graded metabarriers capable of suppressing both PSV1 and PSV2 modes over a broad frequency range for potential applications in vibration control and seismic isolation. [ABSTRACT FROM AUTHOR]

Accurate topographic data are essential for quantitative structural analysis, both in natural settings and in the laboratory. The selection of modeling materials (with appropriate rheological properties) is known to be fundamental for the success of scaled physical analog experiments. However, the optical properties of analog materials and their impact on the reliability and precision of high‐resolution topographic reconstructions have not (to our knowledge) previously been assessed. Here we evaluate the effects of material composition, color, and grain size on Structure‐from‐Motion (SfM) photogrammetry reconstruction efficacy for deformed and undeformed model configurations in the laboratory. Image collections for photogrammetry are acquired from multiple camera positions with a handheld digital camera, and reconstructions are registered using ground control points in a local coordinate system. Static experiments show that low reflectivity granular materials (e.g., silica sand, volcanic ash, pumice, and Al2O3) yield relatively reliable photogrammetry data for a wide range of grain sizes (44–2,400 μm) but larger grain sizes (≥250 μm) provide more robust results. Reflective materials (e.g., glass beads, wet clay) yield less reliable point‐clouds but the addition of low‐reflectivity granular materials (e.g., Al2O3 grains) on the surface of wet clay improves reconstruction results, with higher grain densities typically yielding lower point‐cloud residuals. SfM‐photogrammetry reconstruction of deformed clay analog models tends to improve at higher extension magnitudes because of fault and associated texture development on model surfaces. We anticipate that our results will help practitioners to improve the precision and reliability of photogrammetric data acquired in the analog modeling laboratory. Key Points: Low‐reflectivity granular materials yield more reliable Structure from Motion topographic reconstructions than wet clay or reflective granular mediaApplication of granular material to wet clay surfaces improves the reliability and precision of model surface reconstructionsFault development imparts surface texture to model surfaces, improving topographic reconstruction results [ABSTRACT FROM AUTHOR]

This study aims to investigate the flow characteristics of water–sand mixture in fractured porous media through a series of laboratory experiments. The experiments focus on examining the transport characteristics of water–sand mixture with varying grain sizes, glass bead gradations, sand mass fraction and outlet conditions. The results show that an increase in grain size causes a more pronounced nonlinear variation in large pressure gradient, resulting in a predominantly longitudinal flow pattern with a 'multi-arc' flow state. Water–sand mixture with various glass bead gradations exhibits aggregation effects in porous media. The discrete element method–computational fluid dynamics (DEM–CFD) two-way coupling method is used to simulate water–sand flow in fractured porous media using the three-dimensional particle flow code (PFC3D). The simulation shows that the fracture has a more significant constraint effect than the pore due to the significant variation in internal contact force. A response surface optimization method is utilized to establish multi-factor response models. The correlation between flow, fracture inlet pressure, pore inlet pressure and water–sand mass is analyzed to predict accurately the variation of water–sand outflow. Based on the least square method, multivariate regression fitting equations are developed using sand grain size, gradation and sand mass fraction to predict the dynamics of fluidity I and non-Darcy factor β. The equations are found to be effective in forecasting the dynamics of these factors and provides valuable insights for assessing. These results can be used to predict the movement behavior of fluid in fracture-pore composite media and provide theoretical guidance for preventing disasters such as water–sand inrush. Highlights: A shift in the flow pattern of water-sand mixture from a grid-like structure to a multi-arc structure is found as the size of sand particles increases. Water–sand flow in fracture–pore channel is established based on the DEM–CFD two-way coupling method. Multi-factor response models for water-sand outflow are established by using the method of response surface optimization. Multiple regression fitting equations are established based on the least squares method to predict the evolution of fluidity I and non-Darcy factor β. [ABSTRACT FROM AUTHOR]

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The research investigates the sound absorption properties of potassium polyacrylate (PPA) composites, particularly those augmented with clay and porous hollow glass beads within a hydrogel template. This unique material combination shows promise for efficient sound absorption, relevant in industries requiring effective noise control like acoustic engineering and construction. Experimental assessment focused on measuring the sound absorption coefficient, crucial for quantifying a material's ability to absorb sound energy across various frequencies. Incorporating clay and porous hollow glass beads introduces complexities, emphasizing the need for precise acoustic performance prediction. Collected data from sound absorption coefficient measurements formed the basis for training an Artificial Neural Network (ANN) model. Leveraging the ANN's pattern recognition capabilities, the model learned from diverse composite compositions, enabling accurate prediction of sound absorption coefficients for varying material compositions. This predictive model streamlines material design, offering a systematic approach to tailor composite acoustic characteristics. Integration of machine learning, particularly ANNs, enhances accuracy and expedites material design and optimization, contributing to innovative and customizable sound-absorbing materials for diverse industrial applications. [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]

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]

By investigating the materiality of colonial encounters, specifically the consumption of introduced commodities by Indigenous peoples, archaeologists can explore questions concerning value, agency, consumer choice and localization. This has the significant capacity to broaden understandings of intercultural encounters and challenge colonial narratives. Glass beads represent one of the earliest foreign material culture introductions to the Indigenous peoples of Australia. The rock-shelter site of Madjedbebe, best known for yielding the oldest evidence to date for human occupation in Australia, also contains one of the largest assemblages from an Indigenous site context in Australia—51 glass beads and associated fragments. We present here an analysis of these objects—through attribute and microwear analysis—in concert with the archival record, to reveal the ways in which Bininj (Aboriginal people) incorporated glass beads into their own lifeways. [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]

Epoxy resin/hollow glass beads-chopped basalt fiber (EP/HGM-CBF) composite foam materials with different fiber mass fractions of CBF were prepared. The effects of the solution corrosion environment on the compression properties of the specimens were investigated by immersing the composite foam material specimens in distilled water, seawater, and seawater with five times the concentration of the compounds, and the causes were analyzed by combining scanning electron microscope photographs and EDS energy spectrometry. The study shows that the moisture absorption rate of the specimen first increases and then decreases with the increase of fiber mass fraction, and the moisture absorption rate is the largest at 10% fiber mass fraction, and the moisture absorption rate is larger in distilled water than in seawater, and the increase of the particle concentration in the solution decreases the diffusion coefficient of the solution. In the solution-immersed corrosive environment, the compression properties of EP/HGM-CBF composite foams all increased with the increase of CBF mass fraction, and reached a maximum when the CBF mass fraction was 30%, and the greatest increase in compression strength and compression modulus was seawater with five times the concentration of the compounds, and the compression strength was increased by 28.4% compared with that of the specimens without CBF. The solution corrosive environment decreased the compressive mechanical properties of the specimens, and the damage forms of the composites were different in the distilled water and seawater environments; the distilled water environment was mainly physical damage such as the dissolution of resin leading to interfacial debonding, whereas the seawater environment was mainly chemical damage due to the dissolution of the interfacial structure by elemental Cl. [ABSTRACT FROM AUTHOR]

"Radical Stitch: Art Gallery of Hamilton, February 11–August 27, 2023" is an exhibition at the Art Gallery of Hamilton, Canada, celebrating 37 artists across Turtle Island through beadwork. The show explores the relational network of artists and the sharing of cultural knowledge through beadwork as a form of storytelling. The exhibition, currently at the National Gallery of Canada, Ottawa, showcases diverse perspectives and histories, confronting difficult pasts while highlighting the generosity and reciprocity embedded in beadwork as a language of shared experiences." [Extracted from the article]

The possibility of fixing velocities of fluid motion in model porous medium (glass beads) by measuring the transverse relaxation time T2 by spin echo method is shown. The magnetic field gradient arising due to the difference in the magnetic permeability of the fluid and the porous medium causes a decrease in the average time T2, which makes it possible to fix the fluid motion in the absence of an external magnetic field gradient. The addition of magnetic nanoparticles to the fluid under study increases the dependence of T2 on fluid velocity and increases the sensitivity in determining the permeability of porous medium by NMR-relaxometry. [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]

Archaeological research carried out in the Kruger National Park has identified several settlements of early African farmers that date to the Early Iron Age (EIA) – c. AD 200 – AD 1000. Two large EIA settlements, Le6 and Le7, were identified in 1977 on the southern bank of the Letaba River, opposite its confluence with the Tsende. Intermittent excavations of these sites were carried out between 1977 and 1989, but results have remained largely unpublished. These sites, which date back to the ninth century, have been the focus of new and ongoing research since 2021. The research has revealed that these communities were among the very first in the South African interior to participate in trade with the wider Indian Ocean world. This article contextualises the EIA of the Letaba River and surrounds with a specific focus on the history of research at Le6 and Le7 as well as briefly discusses new research at these sites. [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]

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]