Glass Fragments Research Articles

Review of the Main Mechanical Testing Methods for Interlayer Characterization in Laminated Glass

In the last decades, the use of structural glass has increased exponentially. The reliability of brittle structural glass elements is considerably improved if laminated glass elements are chosen because, in this case, a redistribution of internal forces is permitted once a limited breakage occurs. Thus, instead of monolithic glass, composite materials consisting of two or more glass plies bonded together using a polymeric film as an interlayer are used. In the event of glass failure, because of the chemical bond between the different materials, the adhesion to the interlayer prevents glass fragments from scattering. To design structural elements, the definition of the mechanical features of the interlayer is necessary. However, several standards and techniques can be applied, considering the characterization of either the interlayer itself or the laminated glass. The paper reviews the main existing methods and focuses on the standard suggested by the CEN/TS 19100:2021, analyzing in detail the effect of the different parameters involved. A numerical model is presented to account for the effect of the stress level, glass, and interlayer thickness. Although the standard leaves a certain degree of freedom in choosing those parameters, in some cases the results can differ.

The impact of substrate dampness on the transfer of glass fragments to upper garments when breaking windows

Glass fragments are often recovered from garments worn by the authors of certain types of crimes and are useful as they present strong connections to the scene at both the source and activity level. It is known that the transfer of glass fragments is impacted when recipient garments are dampened, such as by rain, however, the details of the effect are not clear. This research aimed to determine the impact of substrate dampness on glass retention. Across the three test garments, a cotton t-shirt was found to increase in retentiveness with increasing dampness, while a wool/polyester blend jumper and a cotton hoodie were both found to increase only to a point, before decreasing again when the garment was saturated. This is attributed to the construction of the fabrics, as it does not appear to be related to the identity of the textile itself. It was also found that the size distribution of fragments changed with dampness. All the garments retained a smaller proportion of fragments less than 0.5 mm in size when saturated or dampened than when dry, along with an increase in the proportion of fragments in the 1–1.5 mm and greater than 1.5 mm size categories. These results indicate that is important to consider the impact of substrate dampening when relevant, and that this consideration must be done holistically as different substrates respond to dampening in different ways. It also indicates that consideration of the size distribution in fragment populations may reveal additional information in complex scenarios.

Ibex Hollow Tuff from ca. 12 Ma supereruption, southern Idaho, identified across North America, eastern Pacific Ocean, and Gulf of Mexico

Abstract The Ibex Hollow Tuff, 12.08 ± 0.03 Ma (40Ar/39Ar), is a widespread tephra layer erupted from the Bruneau-Jarbidge volcanic field of southern Idaho. Tephra from this eruption was deposited across much of western and central North America and adjacent ocean areas. We identified the Ibex Hollow Tuff at Trapper Creek, Idaho, near its eruption site, and at 15 distal sites, from the Pacific Ocean to the Gulf of Mexico, by the chemical composition of its glass shards, using electron-microprobe analysis, instrumental neutron activation analysis, and laser-ablation–inductively coupled plasma–mass spectrometry. By these methods, we distinguished the Ibex Hollow Tuff from overlying and underlying tephra layers near its source and at distal sites. Fluvially reworked Ibex Hollow Tuff ash was transported by the ancestral Mississippi River drainage from the interior of the North American continent to the Gulf of Mexico, where it is present within an ~50-m-thick deposit in marine sediments in the subsurface. The minimum fallout area covered by the ash is ~2.7 million km2, with a minimum volume of ~800 km3, and potential dispersal farther to the north and northeast. The areal distribution for the Ibex Hollow Tuff is similar to that of the Lava Creek B (0.63 Ma) supereruption. The Ibex Hollow Tuff represents a unique chronostratigraphic marker allowing a synoptic view of paleoenvironments at a virtual moment in time across a large terrestrial and marine region. The Ibex Hollow Tuff is also an important marker bed for North American Land Mammal Ages, and it coincides with climatic cooling in the middle to late Miocene documented in marine cores.

Timescale of Emplacement and Rheomorphism of the Green Tuff Ignimbrite (Pantelleria, Italy)

AbstractWe present a multidisciplinary study based on Differential Scanning Calorimetry (DSC), paleomagnetic analysis, and numerical modeling to gain information on the timescales of syn‐ and post‐depositional ductile deformation of the strongly welded and rheomorphic Green Tuff ignimbrite (GT; Pantelleria, Italy). DSC measurements allow the determination of glass fictive temperatures (Tf; i.e., the parameter accounting for the cooling dependence of glass structure and properties). Using a Tf‐based geospeedometry procedure, we infer the cooling rate (qc) experienced by the glassy phases in different lithofacies within the GT formation. Glass shards from the basal pumice fall deposit record a fast qc of ∼10°C/s. In contrast, the ignimbrite body returns slow qc values depending on the stratigraphic position and lithofacies (basal/upper vitrophyres, fiamme‐rich and rheomorphic layers), ranging from ∼10−2 to ∼10−6 °C/s. Moreover, paleomagnetic analyses of the natural remanent magnetization of ignimbrite matrix and embedded lithic clasts indicate an emplacement temperature higher than 550–600°C. By integrating calorimetric and paleomagnetic datasets, we constrain a conductive cooling model, describing the ignimbrite's temperature‐time‐viscosity (T–t–η) evolution from the eruptive temperature to below Tf. Outcomes suggest that the upper and basal vitrophyres deformed and quenched over hours, indicating that the entire GT underwent intense syn‐depositional ductile deformation. Furthermore, the central body remained above Tf for a much longer timespan (>1 month), enabling post‐emplacement rheomorphic flow. Lastly, we discuss the critical role of mechanisms such as shear heating and retrograde solubility of volatiles, in locally controlling the rheological behavior of the GT.

The physical volcanology of large-scale effusive and explosive silicic eruptions in southeastern Saurashtra, Deccan Traps

AbstractSilicic magmatism, minor overall in the ∼65.5 Ma Deccan Traps continental flood basalt (CFB) province of India, was widespread in the Saurashtra region. We describe the physical volcanology of silicic volcanics and dykes exposed around Rajula–Savarkundla–Gariyadhar–Talaja towns in southeastern Saurashtra. The silicic volcanics conformably overlie basaltic lavas, suggesting rapid subaerial volcanism, and the sequence shows gentle tectonic dips (∼15°) towards the Arabian Sea. Rhyolites and dacites with preserved thicknesses of tens of metres show intense internal rheomorphic deformation, and a dacite shows a well-formed basal autobreccia. The rheomorphic rhyolites, and vitrophyres which often underlie them, lack vitroclasts (glass shards and pumice clasts). They have very similar mineral assemblages (quartz and alkali feldspar phenocrysts, and crystal cargoes dominated by calcic plagioclase and clinopyroxene or orthopyroxene, sometimes with olivine). The rheomorphic units are thus flood rhyolite and dacite lavas, apparently common in the northern-northwestern Deccan, and the vitrophyres their basal chilled parts. Tuffs (including crystal-vitric Plinian fallout ash) and eutaxitic ignimbrites formed from pyroclastic density currents; one tuff contains extraordinary numbers of lithophysae. Ridges of rhyolitic tuff breccias with pervasive secondary silicification and ferruginization represent pyroclastic eruptive fissures. The area thus records large-scale effusive and explosive silicic eruptions. Mafic and silicic dykes intrude the basaltic lavas and rarely the silicic volcanics. Mafic enclaves in several silicic dykes and some volcanics indicate magma mingling as a common phenomenon. The seaward-dipping volcanic units define a regional-scale flexure comparable to coastal flexures in CFB provinces worldwide, suggesting extensive block-faulting of this classical volcanic rifted margin.

Insights into the secondary glass production in Roman Aquileia: A preliminary study

A set of 29 glass shards, selected from numerous ones recovered in 2017 in Aquileia (NE Italy), was studied to provide evidence of local glass production for that specific area in antiquity. These shards can be dated between the 1st and the 4th century AD. The chemical composition of glass samples was obtained using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) that enables to quantify the concentration of major, minor, and trace elements needed to investigate provenance and compositional groups and sometimes to suggest a chronological frame of the samples. To ensure that the samples are homogeneous enough to perform accurate quantification, some of them were also analysed by instrumental neutron activation analysis (INAA). Most of the chunks, working wastes, and artefact shards considered in this work exhibited similarities among them in terms of composition, which likely indicates that glass working activities were practised at the site of recovery. The analyses demonstrated the presence of both recycled glass and primary glass. Interestingly, the compositional data of raw primary glass point to both Syro-Palestinian and Egyptian regions as sourcing areas, confirming the role of the Roman city of Aquileia as a network node for the trade of goods. In addition, some particularly coloured glass fragments showed a composition typical of glass produced starting from the 1st or 2nd century AD, requiring specific types of furnaces and procedures for its manufacture, and suggesting the possibility of local highly-specialised production. The preliminary results of this work strengthen the hypothesis that Aquileia was a thriving centre, either for working primary glass or for glass recycling and production of objects with particular colours.

Blast response of laminated glass: A gas-gun experimental investigation of the fracture pattern and yield lines observed in full-scale blast tests

The applications of architectural and automotive laminated glass continue to grow. This is largely due to the enhanced safety in extreme events, such as blast. However, the complex interaction between the glass fragments and the polymer interlayer after glass fracture is still only partially understood, with existing analysis methods adopting a semi-empirical approach for the post-fracture response. These include a plastic yield-line analysis based on a failure pattern repeatedly observed during blast tests. In recent research it was demonstrated that yield lines can develop in fractured laminated glass through the composite bending action of the glass fragments, working in compression, together with the interlayer working in tension. This paper investigates the influence of the inertia loading associated with blast response, which has not been explicitly studied previously, with the aim of understanding the pattern of yield lines observed in blast tests. Impact tests are performed on laminated glass specimens using foam projectiles launched from a gas gun, which simulate the loading from a blast pulse. These tests demonstrate that the yield line pattern formed under short-duration dynamic loading depends on the loading intensity, thereby providing further evidence of a dynamic, plastic collapse mechanism in which inertia plays a significant role.

Addressing forensic science challenges with nuclear analytical techniques – A review

We review the application of Nuclear Analytical Techniques (NATs) to forensic problems for the first time. NATs include neutron activation analysis (NAA), carried out in nuclear reactors for elemental analysis; accelerator-based techniques, mainly Ion Beam Analysis (IBA) for elemental and molecular analysis; and Accelerator Mass Spectrometry (AMS) for dating of traces of forensic interest by “radiocarbon dating” and other related methods. Applications include analysis of drugs of abuse, food fraud, counterfeit medicine, gunshot residue, glass fragments, forgery of art objects and documents, and human material. In some applications only the NATs are able to provide relevant information for forensic purposes. This review not only includes a wide collection of forensic applications, but also illustrates the wide availability worldwide of NATs, opening up opportunities for an increased use of NATs in routine forensic casework.

Light Emitting Concrete by Replacing the Coarse Aggregate with Industrial Glass Waste (100%,70%,50% Replacement)

The project involves the development of light-emitting concrete by replacing coarse aggregate with leftover shards of industrial glass, which act as the new type of innovation on this field. The discarded glass will be reused in this project, which will contribute to the development of transparent concrete. This is characterized by its ability to transmit light. This material can be used for various applications and is expected to give a new image to concrete. This type of concrete is commonly used in smart construction projects. It can be used to create a sense of the structure's stress and improve the appearance of the building.

A Holocene tephrochronological framework for Finland

Regional tephrochronological frameworks serve as dating and correlating tools that enable critical assessment of the validity of single cryptotephra findings. In this study, our aim was to construct an outline for a Finnish Holocene tephra framework by investigating 12 peatlands and one lake site for presence of cryptotephra. As a result, glass shards from 19 individual tephras were geochemically characterized and correlated to their source volcanoes in Iceland and Alaska. Fifteen of these tephras were identified in Finland for the first time. The oldest identified cryptotephra in the Finnish environmental records is the 7 ka Hekla 5 tephra, and the youngest one is the Askja 1875. The identification of two Alaskan tephras (White River Ash eastern lobe and Aniakchak tephra) in Finland demonstrates an opportunity for intercontinental tephra correlations. The first Finnish Holocene tephrochronology presented here reveals a great potential for using tephrochronology as a dating method in Finland and is expected to aid in future cryptotephra research in the region. Additionally, the cryptotephra findings in this study help to refine the dispersal areas of several Holocene tephras.

Manufacturing Technology and Usage of Glass Fragments in Jahangir Dome and Goriye, Sasanid Sites in Western Iran

This article introduces the Sasanid glass found during excavations at the western Iranian sites of Jahangir Dome and Goriye in Ilam province. In addition to architectural remains, different types of Sasanid pottery, glass, and metal vessels were found at these sites. Considering the importance of the glass industry in this period, the purpose of this article is to study the typological styles and chemical compositions of the glass fragments excavated at Jahangir Dome and Goriye to identify the origin of the vitreous materials. Glass fragments from these sites are divided into four groups based on the form and typology and include: vessel fragments, cosmetic containers, bracelets, and beads. According to the elemental analysis, silicon dioxide, sodium oxide, and calcium oxide are the main chemical components in the studied samples, and analyzed glass materials are of a plant-ash silica-soda-lime glass-type.

Historical explosive activity of Mount Melbourne Volcanic Field (Antarctica) revealed by englacial tephra deposits

Five tephra layers named BRH1 to 5 were sampled in an ice cliff located on the north-eastern flank of Mount Melbourne (northern Victoria Land, Antarctica). The texture, componentry, mineralogy, and major and trace element compositions of glass shards have been used to characterize these layers. These properties suggest that they are primary fall deposits produced from discrete eruptions that experienced varying degrees of magma/water interaction. The major and trace element glass shard analyses on single glass shards indicate that Mount Melbourne Volcanic Field is the source of these tephra layers and the geochemical diversity highlights that the eruptions were fed by compositionally diverse melts that are interpreted to be from a complex magma system with a mafic melt remobilizing more evolved trachy-andesitic to trachytic magma pockets. Geochemical compositions, along with textural and mineralogical data, have allowed correlations between two of the englacial tephra and distal cryptotephra from Mount Melbourne, recovered within a marine sediment core in the Edisto Inlet (~ 280 km northeast of Mount Melbourne), and constrain the age of these englacial tephra layers to between the third and the fourth century CE. This work provides new evidence of the intense historical explosive activity of the Mount Melbourne Volcanic Field and better constrains the rates of volcanism in northern Victoria Land. These data grant new clues on the eruptive dynamics and tephra dispersal, and considerably expand the geochemical (major and trace elements) dataset available for the Mount Melbourne Volcanic Field. In the future, this will facilitate the precise identification of tephra layers from this volcanic source and will help define the temporal and spatial correlation between Antarctic records using tephra layers. Finally, this work also yields new valuable time-stratigraphic marker horizons for future dating, synchronization, and correlations of different palaeoenvironmental and palaeoclimatic records across large regions of Antarctica.

Comparing the Accuracy of Micro-Focus X-ray Technology to Standard Clinical Ultrasound for Locating Small Glass Foreign Bodies in Soft Tissue

Foreign bodies are found in as many as 15% of traumatic wounds. Point of Care ultrasound (POCUS) is now considered reliable for detecting FBs in wounds. Unfortunately, up to 38% of these FBs are initially missed, resulting in infections, delayed wound healing, and loss of function. Microfocus X-ray imaging (MFXI) has a significantly higher resolution (up to 100×) than conventional X-ray imaging. Therefore, it can potentially be used for Point of Care diagnostics. Up to seven glass fragments smaller than 2.5 mm were embedded in each of the 58 chicken wings and thighs. Two control samples were prepared with no glass fragments. Five emergency medicine physicians with ultrasound training imaged the samples with a Butterfly iQ+ at 1 to 10 MHz center frequencies and counted the glass pieces. This device is an example of handheld PCUS equipment that is particularly valuable in resource-limited areas and austere settings where portability is a significant factor. The same five physicians counted the number of foreign bodies in each X-ray image. The physicians were not trained to read micro-focus X-ray images but had read standard X-rays regularly as part of their medical practice and had at least 3 years of hands-on clinical practice using POCUS. Across physicians and samples, raters correctly identified an average of 97.6% of FBs using MFXI (96.5% interrater reliability) and 62.3% of FBs using POCUS (70.8% interrater reliability).

Effects of post-fracture repeated impacts and short-term temperature gradients on monolithic glass elements bonded by safety films

Weathering and operational conditions, as known, have significant impact on typical constituent materials which are used for many construction applications. Among others, structural glass solutions can suffer for these effects in terms of major modification of material properties of interlayers, bonds, connections, gaskets and polymeric components in general. In this paper, the attention is given to the effects of repeated low-amplitude impacts and short-term temperature gradients for the characterization of load-bearing capacity in monolithic glass elements retrofitted by safety films. Especially for existing glass systems which are made of monolithic glass with limited strength and resistance capacity against ordinary and accidental mechanical loads, safety films are commercially available for retrofit interventions. They are primarily expected to keep together glass fragments in case of breakage, and thus minimize possible injuries. Besides, after first fracture, the so obtained glass-film composite elements have uncertain residual mechanical capacity against ordinary loads, given that it mostly depends on thin films composed of Polyethylene terephthalate (PET)-layers and pressure sensitive adhesives (PSAs). To this aim, a set of experiments (for a total of 950 configurations) is carried out in laboratory conditions (30 °C) on small-scale samples of fractured annealed monolithic glass elements bonded by commercial safety films, under repeated low-amplitude impacts / vibrations (S1-TR series), or additionally subjected to preliminary short-term thermal gradients (S2-TC1 series cooled at +5 °C and S3-TC2 series at −20 °C). Localized impacts are quantified in acceleration peaks in the range of 2 ÷ 14 m/s2 and rotations at supports in the order of 15 ÷ 20°. The interpretation of dynamic experimental results is carried out in terms of post-fracture vibration frequency (based on classical operational modal analysis techniques) and used, with the support of simplified analytical models or Finite Element (FE) numerical simulations, to characterize the response of cracked glass-film samples. Most importantly, the vibration frequency decrease is used to quantify their residual load-bearing capacity under unfavourable conditions, and to quantify the post-critical benefit of thin bonding safety films under unfavourable conditions.

Basin-wide erosion and segmentation of the Plio-Pleistocene forearc basin in central Japan revealed by tephro- and biostratigraphy

The basement of the Tokyo metropolitan area consists of the Miocene–Pleistocene forearc basin fills that are well exposed around Tokyo Bay, especially on the Miura and Boso peninsulas. The forearc basin fills on these two peninsulas are called the Miura and Kazusa groups, and they were deposited during the late Miocene–Pliocene and Pliocene–middle Pleistocene, respectively. Because many biostratigraphic datum planes, paleomagnetic reversal events, and other chronostratigraphic tools are available for these deposits, they provide the “type stratigraphy” of other equivalent sedimentary sequences on the Japanese islands and in the northwest Pacific. However, the use of such stratigraphic markers has not been fully applied to understand the architecture of a basin-wide unconformity between the Miura and Kazusa groups called the Kurotaki unconformity. For our study, we made correlations among the Pliocene vitric tephra beds based on their stratigraphic levels, lithologic characteristics, the chemical compositions of glass shards, and calcareous nannofossil biostratigraphy. As a result, we were able to correlate tephra beds Ng-Ky25 just above the C3n.3n normal subchronozone (4.7 Ma), IkT16-An157.5 and IkT19-An158.5 near the top of the Mammoth reverse polarity subchronozone (3.21 Ma), and Ahn-Onr (2.6–2.7 Ma) across Tokyo Bay on the Miura and Boso peninsulas. We were able to recognize erosional surfaces and coeval mass-transport deposits immediately below the top of the Mammoth reverse polarity subchronozone, which suggests that submarine landslide(s) may have produced the lack of stratigraphic horizons (4.5–3.2 Ma) in the Miura and eastern Boso regions. Basal pebbly sandstone beds pervasively cover the erosional surfaces, and they show lateral variations into the thick (up to 60 m) mass-transport deposits and overlying turbidite sandstones. The lateral variations in sediment thickness of the post-failure deposits suggest that the basin-wide erosion was associated with the initial growth of a basin-bounding structural high that separates two distinct sub-basins in the forearc basin, which resulted in the subsequent onlapping deposition in the earliest stage of the Kazusa forearc basin. The basin-wide erosion marks the initiation of tectonic reconfigurations that led to segmentation of the forearc basin around the Tokyo Bay region.

Islamic glass in the Christian Kingdom of Alwa: Chemistry of shards from Soba, Nubia, Sudan

AbstractExcavations at Soba, the capital of Alwa, between 2019 and 2022 yielded more than 30 glass fragments in addition to a glass cosmetic bottle. An analysis of 30 glass samples has identified glass belonging to a number of compositional groups. The majority of fragments were made of plant ash‐soda glass produced in the Middle East (Iran, Iraq) between the 9th and 10th centuries, and in the Eastern Mediterranean (Levant and Egypt) between the mid‐10th and mid‐12th centuries. Seven fragments were made of mineral–soda‐lime glass produced in 9th‐century Egypt and three high‐lead glasses find analogies in the 9th‐ to 11th‐century glass. Archeological evidence, as well as textual sources, leave no doubt about Alwa’s intense transcultural connections. This article provides the first insight into the chemistry of glass shards from medieval Nubia, and the results of analysis contribute to evidence for long‐distance contacts of Soba, the capital of one of the medieval kingdoms of Sahelian Africa.

Flake formation and composition in soda-lime-silica and borosilicate glasses

Glass is a food contact material that has been used for a long time in food packaging because it is chemically durable and stable. However, when used for a long time in an aqueous solution or under certain conditions in which alteration may occur, solid flakes may be formed. The phenomenon could be observed when the process of boiling water in a glass kettle is repeated. Transparent and shiny needle-shaped glass fragments appear floating in the water, which may cause complaints from consumers.The purpose of this study is to investigate the conditions leading to the formation of flakes and to identify the components of the suspended flakes in glass container.In this study we investigated the formation of flakes at different temperatures (70–100 °C), initial pH values (3–11) and varying the solution composition (with Na+, K+, Ca2+, Mg2+ concentrations from 0.2 to 40 mg/L). Two types of glass materials, soda-lime-silica glass and borosilicate glass (heat-resistance glass) were examined.Results show that flakes were observed under the following conditions: 24 h at more than 90 °C, pH 8, and 20 mg/L Ca2+ for soda-lime-silica glass and more than 100 °C, pH 11 for borosilicate glass. The component of flakes was identified as a mixture of hydrates of magnesium, calcium, and aluminum silicate analyzed by X-ray fluorescence spectroscopy, inductively coupled plasma-optical emission spectroscopy, and X-ray diffraction.

Comparative study on the dynamic compressive, tensile and flexural properties of soda-lime silicate glass

The mechanical behavior of brittle solids are influenced by many factors such as specimen sizes, surface conditions and loading conditions. This work focused on the mechanical properties of a soda-lime silicate glass under three kinds of loading, i.e. compression, tension and flexure. In addition, quasi-static, dynamic uniaxial-unidirectional (UU) and uniaxial-bidirectional (UB) tests were performed. Electromagnetic split Hopkinson pressure bar (ESHPB), a newly developed system, was adopted in the dynamic tests. A high-speed camera was employed to capture the dynamic failure process. Effects of loading rates, specimen sizes, stress waves and loading modes on the mechanical behavior of this glass were comparatively investigated. Testing results illustrated that specimen size and strain rate had significant influence on the strengths. Different from the tensile and flexural strengths, the compressive strength was sensitive to the loading stress waves. The flexural strength was generally higher than the tensile one and they could be mutually converted through the non-local failure theory. Fracture surface of glass fragment after tensile loading was observed by a scanning electron microscope (SEM) to reveal the microscopic features.

Provenance and deposition of a lithified volcanic-rich layer (VRL-5.5) at 5.5 Ma from Central Apennines (Italy)

Two slightly lithified volcanic rich layers (VRL) (former tephra) SVT-2 (San Vittorino) and CAC (Castiglione a Casauria) were sampled from two distinct post-evaporitic Messinian stratigraphic sections (Abruzzo, Central Italy). They crop only few tens of km apart and are predominantly massive, although some specimens show sedimentary structures. Both VRLs were investigated for the first time by field, mesoscopic, X-ray powder diffraction (XRPD), transmission optical microscopy (TOM), scanning electron microscopy (SEM), bulk composition, electron-microprobe analysis (EMPA) and quantitative textural attributes by image analysis. The XRPD analysis detects the presence of a glass phase, plus few (< 2 area %) magmatic-like feldspars, clinopyroxene and biotite and stratigraphically variable sedimentary minerals such as calcite, dolomite, illite and montmorillonite (from 0 to 40 area %). The 2D image analysis performed on SEM microphotographs reveals that both sections are composed of very fine glass shards, magmatic minerals are never isolated, whilst the carbonate crystals mainly fill voids among volcanic particles. Both these VRLs have identical rhyolitic glass compositions that closely overlap with those of previously-studied coeval and stratigraphically related sections occurring in the northern Apennine region and dated as 5.5 Ma. The 2D textural features of glassy particles (length, width, aspect ratio, grain-size distribution, MZ , σi, SKi, KG and roundness) in both SVT-2 and CAC sections are very similar and also close to the northern section of Camporotondo (Marche region). The outcomes provided here indicate that SVT-2 and CAC sections represent the southernmost distal deposits of the same large eruption that occurred about 5.5 Ma (VRL-5.5). They result from distal fallout of tephra through seawater, occasionally remobilised under low energy and localised conditions, especially in the uppermost part of the CAC section. All the VRL-5.5 rocks are probably related to a very large eruption that occurred in the Carpathian-Pannonian magmatic district. The analytical protocols used in this study can be useful to investigate other ancient volcanic-rich layers, corresponding to lithified tephra.

Photochromic safety-glass based on polyurethane interlayer film blend with perovskite quantum dot

In recent years, photochromic glass has been widely used in smart windows, depending on its thermal insulation, concealment and intelligent controllability. However, the safety requirements of photochromic glass are still one of the problems to be solved in practical applications. In this work, a photochromic composite film based on polyurethane/perovskite quantum dots (HPU) has been got by casting blending extrusion process. Then laminated safety glass based on the HPU intermediate films are constructed by hot pressing process, the glass of which shall be coated with a layer of acrylate hot-melt adhesive (PA) before use. Under ultraviolet light, it can be displayed in green from colorless within 0.5 s, and transmittance of laminated glass is almost the same as that of single-layer glass under natural light. The safety of laminated glass based on the glass/PA/HPU/PA/glass structure is evaluated by falling ball impact test. There are no glass fragments falling off and splashing when they are impacted by a 50 g of steel ball falling freely from a height of 1 m. The excellent environmental stabilities have been confirmed by fluorescence spectrum tracking. The intelligent photochromic safety-glass mentioned in this work has great application potential in the fields of building windows, automotives and optical devices.