Glass Grains Research Articles

Tests of Uniaxial Compression of Single Grains

Tests of the uniaxial compression of single grains were performed in a specially designed press, which allowed the recording of an applied load in regard to the time and observation of occurring phenomena in a polarization assay. Three types of grains were tested: quartz sand, glass granules, and crushed glass. The strength tests showed different mechanisms of grain damage depending on the type of grain. In addition, the formation and spread of interference fringes, forming “chains of force” in samples with a large number of grains, were observed by testing glass grains under the polarization assay. A more detailed understanding of the strength characteristics of single grains will allow the verification of the models most commonly used in DEM.

Assessing the Potential of Rare Earth Elements in Bottom Ash from Coal Combustion in Poland.

The aim of the research was to assess the potential of bottom ash from Polish coal-fired power plants as an alternative source of rare earth elements (REY). The potential of these ashes was compared with fly ash from the same coal combustion cycle. The phase and chemical composition, as well as REY, were determined using: X-ray diffraction and inductively coupled plasma mass spectrometry. The tested ashes were classified as inert-low pozzolanic and inert-medium pozzolanic, as well as sialic and ferrosialic, with enrichment in detrital material. The phase and chemical composition of bottom ash was similar to fly ash from the same fuel combustion cycle. The REY content in the ash was 199-286 ppm and was lower than the average for global deposits, and the threshold value was considered profitable for recovery from coal. Bottom ash's importance as a potential source of REY will increase by recovering these metals from separated amorphous glass and mullite and grains rich in Al, Mg, K, and P. The industrial value of bottom ash as an alternative source of REY was similar to fly ash from the same fuel combustion cycle.

Colossal permittivity and excellent temperature stability of BaTiO3 based fine ceramics with controlled grain growth

Dielectric materials with colossal permittivity (CP, εr > 104) have attracted the increasing interest of researchers due to their enormous potential in the fields of sensor, capacitor, energy storage, etc. However, for the explored CP materials, their grains are too large to apply. To control grain growth, the sintering aids of MgO–Al2O3–SiO2 (MAS) cordierite glass and common suppression grain growth of MgO have been introduced to BaTiO3-0.004Y2O3-0.006MnO2 ceramics derived from the commercial BaTiO3 powder with the average grain size of 300 nm. After controlling grain growth, the fine grains with the average grain size of dg ∼300 nm and CP are achieved in BaTiO3 based ceramics sintered in reducing atmosphere. Notably, excellent temperature stability with Δεr/εr25°C lower than 17 % is gained for the present BaTiO3 based ceramics in the temperature range of −60 to 155 °C, meeting the X8S specification (ΔC/C25°C ≤±22 %, −55 °C–150 °C). Based on the X-ray photoelectron spectroscopy (XPS) and Raman spectra, the outstanding dielectric properties of the present BaTiO3 based ceramics is ascribed to the electron-pinned defect-dipole (EPDD) effect induced by YTi′−YBa∙, TiTi′−Vo∙∙−TiTi′ and YTi′−Vo∙∙−TiTi′ defect dipoles. The present BaTiO3 based fine ceramics with colossal permittivity (∼2.9 × 104), low loss (∼0.03) at 1 kHz and room temperature, excellent temperature stability and high resistivity of 3.54 × 109 Ω cm is a promising candidate for the multilayer ceramics capacitor (MLCC).

Research on Glass Classification and Identification Based on Cluster Analysis and Multiple Regression Models

Ancient glass undergoes a large exchange of internal elements with environmental elements in burial, and its composition changes, thus affecting the correct judgement of its category. In order to classify and identify the types of ancient glass, this paper sets different types of glass as the dependent variable, and the grain, weathering or not, and their chemical composition characteristics as the independent variables, so as to form an interpretable classification law. In order to carry out the sub-classification under the same type of glass, then a chemical element content is selected and then the colour of the glass grain is observed under that content. In order to identify the type of glass, this paper builds a multiple regression model on the data of chemical composition and glass type, from which the type of glass is identified. The models established in this paper have passed the stability test.

Detrital record of sediment influx in the Triassic Chuxiong broken foreland basin in southeastern Tibetan Plateau

The Triassic Chuxiong basin represents a classic example of a foreland system that is thought to be associated with the closure of eastern branches of the Paleo-Tethys and subsequent Indosinian collision, yet how it was filled remains poorly understood. Here, we use paleocurrent measurements, sandstone petrology, and detrital zircon UPb geochronology to examine the patterns of basin fill. Paleocurrent reconstruction indicates that although some evidence exists for axial transport, the basin was mainly filled transversely with abundant sediment input from the Paleo-Tethyan suture to the west and the Kangdian High to the east. Qualitative determination of sandstone petrology shows that the lithic fragments contained within the Late Triassic strata are not of a uniform mode: volcanic lithics and glass grains are contained within nine Carnian and Rhaetian samples from the western part of the basin, but rarely observed in thirteen samples from the eastern basin. Similarly, detrital zircon UPb geochronology of sandstone samples from five sections reveals marked temporal and spatial changes in their age signatures that can be divided into three distinct types. Type-1 age spectra are represented by a narrow unimodal age probability peak at ca. 250 Ma that correlates with the Indosinian-aged arc sources developed along the Jinsha Jiang-Ailao Shan and Changning-Menglian sutures. Type-2 also shows a major zircon age population, but with a diagnostic peak at ∼780 Ma that corresponds to the Neoproterozoic basement outcropped in Kangdian High. Type-3 is generally characterized by multimodal distribution with major populations of ca. 200–350 Ma, ca. 400–500 Ma, ca. 700–900 Ma, ca. 1750–2000 Ma, and ca. 2350–2600 Ma. Comparing our new data with existing age spectra for the Triassic strata across the western Yangtze and the Indochina blocks demonstrates that the Chuxiong basin was primarily filled by a magmatic arc along the Paleo-Tethyan suture zone during the Carnian, and mostly fed by a reorganized drainage system by incorporating the fold-thrust belt and uplifted foreland basement as source area when the basin expanded eastward through the Norian and Rhaetian as the basin-fill onlaps onto the basement of Kangdian High. The patterns of sediment dispersal of the Triassic Chuxiong basin not only provide a new example of the interplay between orogen and craton sediment input in the peripheral setting but also highlight that the local basement-cored uplifts may dominate the provenance of a broken foreland system during underthrusting.

Use of glass waste as granular material in pavement layers

The valorisation of waste glass is part of a sustainable development plan. It presents several challenges, starting with the elimination of the various types of waste sent to landfill and the related costs, the reduction of the inconveniences associated with glass (shards, landfill fires), the development of new economic sectors and raw material saving (aggregate quarries). Several research works have previously been carried out to highlight the interest of using waste glass as a partial replacement for unbound granular aggregate in pavement structure. Nevertheless, industrialists remain reluctant to apply such a technique, which encourages researchers to extend their studies in order to properly control the behaviour of granular materials containing glass grains and consequently give more confidence to companies to enforce this technical solution. The present work consists in studying the influence of the shape of glass grains less than 5 mm (rounded and sub-rounded) on the mechanical behaviour of granular pavement materials. The study consists in making a comparison, from a behaviour point of view, between the two forms of glass grains obtained from two different grinding processes. As a result, the Proctor test clearly shows that there is no significant difference between rounded and sub-rounded shape in terms of compactabiliy. It was noted that the addition of particles of recycled glass makes the mixture more insensitive to water. It has been also found that the limiting percentage of addition of glass particles is situated between 20% and 30% reported to the total mass of the mixture.

Physical, Mechanical, and Biological Properties of PMMA-Based Composite Bone Cement Containing Silver-Doped Bioactive and Antibacterial Glass Particles with Different Particles Sizes.

In the present work, antibacterial composite bone cement was designed by introducing a bioactive and antibacterial glass into a commercial formulation. The effect of glass particles' addition on the curing parameters of the polymeric matrix was evaluated; moreover, the influence of the glass particle size on the glass dispersion, compressive and bending strength, bioactivity, and antibacterial effect was estimated. The results evidence a delay in the polymerization kinetics of the composite cement, which nevertheless complies with the requirements of the ISO standard. Morphological characterization provides evidence of good dispersion of the glass in the polymeric matrix and its exposition on the cement surface. The different glass grain sizes do not affect the composites' bioactivity and compressive strength, while a slight reduction in bending strength was observed for samples containing glass powders with greater dimensions. The size of the glass particles also appears to have an effect on the antibacterial properties, since the composites containing larger glass particles do not produce an inhibition halo towards the S. aureus strain. The obtained results demonstrate that, by carefully tailoring the glass amount and size, a multifunctional device for artificial joint fixing, temporary prostheses, or spinal surgery can be obtained.

Volcanogenic fluxes of iron from the seafloor in the Amundsen Sea, West Antarctica

The Amundsen Sea in the Pacific sector of West Antarctica receives meltwater from the fastest retreating Antarctic glaciers, and its coastal polynyas host the highest primary productivity per unit area observed on the Antarctic continental shelf. Polynya productivity provides the base for a robust, diverse ecosystem and is controlled primarily by light and the availability of the micronutrient iron (Fe). While the sources of Fe in the region are not yet certain, Fe could be transported within modified Circumpolar Deep Water (mCDW) that intrudes onto the retrograde shelf and into ice shelf cavities, where it gains buoyancy through the addition of glacial meltwater and is injected into the upper water column when it exits the cavity. Thus, fluxes of dissolved Fe from the seafloor into in-flowing mCDW may ultimately be a source of Fe to the euphotic zone in the Amundsen Sea. To investigate the surface sediment biogeochemistry and the potential for a significant benthic flux of Fe to the waters on the Amundsen Sea shelf, sediment cores were collected at two sites close to the calving fronts of the Pine Island and Thwaites Glacier ice shelves. Pore water was analyzed for trace element content, and sediment was analyzed for physical and chemical properties including organic carbon and trace elements. Using a novel approach based on hypothesized Fe speciation and colloidal particle radius, theoretical Fe fluxes were calculated from pore water gradients and porosity. The fluxes reveal a spatially variable Fe input to the lower water column that could ultimately fertilize primary productivity. Supported by geochemical and physical evidence, we conclude that submarine weathering of volcanic glass grains observed and quantified in seabed sediments at the Pine Island site drives nonreductive Fe fluxes that are 100-fold higher than at the Thwaites site. This study highlights the need for further investigations of benthic-pelagic coupling in the Amundsen Sea region, which will likely be impacted in coming decades by accelerating glacial melting.

Effect of Bi-B-Si-Zn-Al glass additive on the properties of low-temperature sintered silicon carbide ceramics

In this study, the performance of low-temperature sintered Bi-B-Si-Zn-Al glass/SiC composites by vacuum hot-press sintering between 700°C and 1000°C was investigated. The specimen had a relatively preferable density of 95.5% and thermal conductivity of 8.660 Wm−1K−1 after sintering at 900°C for 2 h. The dielectric constant and dielectric loss tangle of the composite were 32.9 and 0.57 at 20 GHz, respectively. The XRD analysis indicated the formation of Bi, Zn and ZnAl2O4 crystals, and the microstructure showed the low contact angle of the glass and SiC grain. Such low-temperature sintered SiC ceramic may have a promising application in the electronic field.

The assessment and treatment of waste from glass fibre production for use as a filler in composites

Waste glass from fibreglass production is waste that is generated at various stages of production. In nature, it is a combination of glass fibres, fine dust, but also larger glass grains, for example also from leakages during production. This material is or may be contaminated by impregnation, lubricants or some impurities that prevent its recovery during production. The main objective of this study is to assess the suitability of glass fibre waste and to optimise the pre-treatment of the raw material for use in the composite. This paper describes the determination of chemical composition, mineralogical composition by X-ray diffraction analysis, determination of bulk density, water absorption and specific surface area. The results obtained are compared with the primary raw material - glass fibre. The results showed that the waste from glass fibre production is primarily composed of silica, calcium, alumina and boron. Minor components include magnesium oxide, sodium oxide, fluorine, iron oxide, strontium oxide, potassium oxide, titanium dioxide, sulphur dioxide and chromium oxide. The specific surface area of treated glass fibre waste correlates with the specific surface area of cement, which is a prerequisite for the use of this waste as a partial substitute for cement in the production of building materials.

Method of complex glass relief surfaces mechanical grinding

Presented research is devoted to solving the problem of treatment complex glass relief surfaces by mechanical vibration grinding. The dependences of the obtained grinding results on the type of relief surface, grain size and vibration parameters are investigated. Results: Mathematical dependences of the change in the light transmission of the ground glass on the type of the ground glass surface pattern, grain size and vibration parameters are obtained.

A Micro Mid‐Infrared Spectroscopic Study of Chang’e‐5 Sample

AbstractThe Chang’e‐5 (CE‐5) mission has successfully returned samples from a site that is much younger than the sites of all previous lunar sampling missions. Sample analysis results reported so far have revealed a more complex sampling area than previously thought, casting uncertainties over the interpretation of remote sensing spectral data and the U and Th abundance derived from the orbital data. Laboratory spectral measurement of the returned samples can serve as validation of remote sensing observations and thus help refine our understanding of the geological evolution of the landing region. In this study we report detailed micro mid‐infrared (MIR) spectral characteristics of individual soil grains of CE‐5 samples. The spectral analysis results show that the CE‐5 olivine grains have low Fo (molar Mg/[Mg + Fe] × 100) consistent with previous studies, indicating a Fe‐rich source region of the mantle or a highly evolved magma. These olivine grains show high level of crystallinity, implying low degree of space weathering. Most of the CE‐5 glasses analyzed are spectrally consistent with mare impact glasses, despite that a few of them may have a volcanic origin. These laboratory spectral analysis of CE‐5 samples in the MIR wavelengths at a micro scale, together with the derived MIR optical constants of the olivine, pyroxene, plagioclase, and glass grains, provide important input for the modeling and interpretation of thermal remote sensing data of the Moon.

Composition, age and origin of Pleistocene turbidite deposits at ODP site 1232, Nazca plate: Implications for volcanism and climate change in central south Chile

A 371 m sequence of Pleistocene age turbidites was recovered at ODP (Ocean Drilling Program) Leg 202, Site 1232 at 39°53.45'on the Nazca Plate, seaward of the Peru-Chile Trench. Coarsest sediments within the turbidites (<300 μm) contain large amounts of fresh, angular volcanic glass shards. We investigated the variation in proportions of coarsest (>149 μm) glass, minerals and polymineralic grains, and microfossils downcore with the goal of discerning temporal changes and their underlying causes. Between 214 and 160 mbsf, the dominant coarse particle type changes from rounded, clay-rich granules, interpreted as altered pumice, upward to fresh, angular volcanic glass. This change correlates with an upward increase in turbidite thickness noted by Leg 202 scientists. Major and trace element analyses of individual glass shards show a geochemical signature consistent with a source within the adjacent Andean Southern Volcanic Zone. New calcareous nannofossil biostratigraphy brackets the sediment ages of the upper 288 m of the section to between 12.47 kyr and 275 kyr, which is consistent with published ages for the upper 97 m of the section and estimated maximum ages.Based on our dating of the section, the observed change in dominant coarse sediment type occurs between 225 and 185 kyr and correlates with a climatic transition from interglacial to glacial conditions. A plausible connection with climate is that the altered pumice grains formed by chemical weathering and fluvial transport under warm surface conditions, whereas the glass shards were transported by aeolian and glacial processes, leading to a lack of weathering and an angular texture. However, as a climate-related temporal change, this scenario conflicts with the absence of a similar change in sediment type during the subsequent Valdivian and Llanquihue interglacial-glacial transition starting at about 125kyr. Therefore, our conclusion is that, although the two coarse sediment types formed and were transported under different climate conditions, the temporal change is related to a shift in sediment source, supply or transportation pathway during the 185–225 kyr interval. A related possibility is that the onset of angular glass involvement in turbidity flows, during a glacial stage, marks the eruption of a new volcanic source or sources. Resolving these possibilities could be addressed with more detailed geochemical analysis.

Geotechnical properties of a bentonite treated with waste glass grains

Geotechnical properties of a bentonite treated with waste glass grains

Preparation and characterization of cobalt-60 glass microspheres for radioactive particle tracking applications

The current work describes development and optimization of a process for preparation of cobalt-60 glass microspheres. These microspheres have potential for applications in radioactive particle tracking (RPT) studies in multiphase flow systems. In the first step of preparation, soda lime glass containing 5–10 wt% cobalt oxide was produced through melt-quench method. Subsequently, cobalt glass microspheres (CMSs) were prepared by microwave heating of tiny glass grains in presence of graphite. In the final step, radioactive cobalt-60 microspheres (RMSs) were produced by neutron irradiation of the CMSs in a nuclear reactor. The CMSs were characterized for surface morphology, elemental composition, homogeneity, crystalinity using SEM, EDX and XRD, respectively. The thermal behaviour of the microspheres was characterized by TG and DSC analysis. The size distribution of CMSs analyzed by SEM was found to be in the range 500–2000 μm. The preparation step was optimized to produce adequate activity in a single microsphere, so that they can be utilized for RPT applications.

The effect of the incorporation of catalase mimetic activity cations on the structural, thermal and chemical durability properties of the 45S5 Bioglass®

Understanding the effect of the incorporation of doping ions into the structure, thermal properties and chemical durability of bioactive glasses is fundamental for the design of new compositions with tailored biological functions and applications. In this work, we have applied a combined experimental and computational approach to unravel the effect of adding metal oxides of Ce, Ti, V, Mn, Fe, Co, Cu, and Zr that impart catalase mimetic activity to the 45S5 Bioglass® on its density, thermal properties and chemical durability. UV-Vis-NIR spectroscopy and temperature-programmed reduction (TPR) experiments allowed us to determine the oxidation states of the doping cations in the bulk of the glasses, Differential Thermal Analysis has been used to determine the glass transition and crystallization temperature, whereas the chemical durability in water was determined by following the hydrolytic resistance of glass grains at 98 °C standard method. The experimental results have been interpreted at the atomic level by exploiting reliable bulk and surface structural models of the investigated glasses generated by using Molecular Dynamics Simulations. Structure-property relationships helpful for the rational design of new glass compositions have also been inferred.

Fabrication of Superhydrophobic Self-Cleaning Coatings by Facile Method: Stable after Exposure to Low Temperatures and UV Light

Self-cleaning hydrophobic surfaces attracted public attention last few decades after discovering of lotus ef-fect. Ability of lotus leaves to keep cleanness in relatively dirty places and to clean up itself during rains di-rected to the development of novel materials and surface structure modification. The surface with such smart properties may have the potential for cost-effectiveness in the case of application in skyscrapers, high build-ings, etc. Two main criteria for the surface to express hydrophobic behavior are roughness and low surface energy of the coating material. In this study, superhydrophobic self-cleaning coatings were prepared by a simple, facile, and cheap method using easily available materials, such as polydimethylsiloxane (PDMS) and TiO2 nanoparticles, and fully characterized for direct usage. PDMS is a bonding layer and TiO2 nanoparticles are a reinforced composite to form roughness, which shows superhydrophobicity. Characterizations showed that the prepared superhydrophobic coating has a water contact angle of up to 165.5°, with sliding angle of less than 5º. Also self-cleaning and surface microfluidic properties have been studied. The superhydrophobic properties of these coatings do not change even after exposure to their surface to low temperatures and UV light. SEM images confirm the rough structure of obtained surface on glass and sand grains.

Ultrabroadband mid-infrared emission from Cr2+:ZnSe-doped chalcogenide glasses prepared via hot uniaxial pressing and melt-quenching* *Project supported by the Key Research and Development Program of Zhejiang Province, China (Grant No. 2021C01025), the National Natural Science Foundation of China (Grant Nos. 61975086 and 61605095), the Zhejiang Provincial Natural Science Foundation of China (Grant No. LY19F050004), the National Key Research and Development Program

We reported an ultrabroadband mid-infrared (MIR) emission in the range of 1800 nm–3100 nm at room temperature (RT) from a Cr2+:ZnSe-doped chalcogenide glasses (ChGs) and studied the emission-dependent properties on the doping methods. A series of Cr2+:ZnSe/As40S57Se3 (in unit wt.%) glass-ceramics were prepared by hot uniaxial pressing (HUP) and melt-quenching methods, respectively. The glass-ceramics with MIR emission bands greater than 1000 nm were successfully prepared by both methods. The effects of matrix glass composition and grain doping concentration on the optical properties of the samples were studied. The occurrence state, morphology of the grains, and the microscopic elemental distributions were characterized using x-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectrometer (EDS) analyses.

Performance of mortars based on recycled glass as aggregate by accelerated decay tests (ADT)

The incorporation of crushed glass as a substitute for natural aggregates in mortar and concrete represents a positive impact on the manufacturing processes. The use of glass residues can lead to the improvement of certain properties of sustainable construction products. In these cases, it is important to analyse in detail the behaviour of the material to verify possible applications at an industrial level and contribute to the development of new construction products and solutions. This work studies the behaviour of mortars with recycled glass as a partial replacement of aggregate against common accelerated decay tests, such as salt crystallization, freezing and thermal shock. The influence on the basic physical and mechanical properties has been evaluated by statistical analysis of the results, observing a particularly significant improvement in the resistance of mortars with recycled glass against the expansive action of salt crystallization (>20%). The influence of alteration processes on the internal structure has been analysed by ultrasound transmission tests and its correlation with Young’s modulus. The values obtained are in the range of similar materials, having the samples subjected to freezing test a major degree of deterioration. The internal structures have been studied by scanning electron microscopy, observing in samples subjected to salt crystallization tests a greater homogeneity and a lower degree of microcracking in the aggregate/paste interfaces of the glass grains.

Effect of the process atmosphere on glass foam synthesis: A high-temperature environmental scanning electron microscopy (HT-ESEM) study

The effect of the process atmosphere composition on the foam formation of cathode-ray tube (CRT) glass containing graphite and MnO2 was studied using in situ environmental scanning electron microscopy at high temperature (HT-ESEM). When compared to He+4% H2, O2 or air, water steam facilitates glass grain sintering. This is probably due to the formation of hydroxyl groups at the glass grain surface that locally decrease the glass viscosity. We have shown that increasing the steam pressure from 50 Pa to 750 Pa decreases both sintering and foaming onset temperatures by approximately 100 °C, favouring the formation of closed pores in viscous glass. At high temperature, the presence of water steam or oxygen promotes foam formation, while the presence of a reducing atmosphere (He+4%H2) limits glass melt foaming. A synergetic effect of O2 and H2O on the onset temperature of glass sintering and foam formation is evidenced.