Float Glass Research Articles

Supply and Demand of the Fundamental Analysis Framework for Float Glass

Supply and Demand of the Fundamental Analysis Framework for Float Glass

Experimental analysis of glass failure criteria under different thermal conditions

The initiation of the first crack mainly determines the criteria for glass failure. However, the extended consequences of cracking, with the formation of multiple cracks merging, result in fallout conditions under varying thermal loads that become more critical. Point-supported glass arrangements are globally used in high-rise and energy-efficient buildings for architectural ingenuity aimed at a low budget. However, the formation of cracks due to thermal load resulting in glass breakage could infuriate the overall fire dynamics of the enclosed area. Therefore, experimental study and prediction of glass failure become very crucial. The present experimental study focuses on finding the most critical parameter that may quantify the cause of glass failure and further breakage in fallout conditions under varying thermal loads. 45 experiments were carried out on float glass of 300 × 300 mm2 with 4 mm, 6 mm, 8 mm, 10 mm, and 12 mm with continuous fuel supply arrangements. Critical parameters analysed were the time of crack initiation, glass temperature at the time of cracking, maximum temperature difference at glass failure, and thermal strain caused by the temperature difference on the glass surface. The range of minimum and maximum temperature difference recorded on the glass surface for the present study was between 30–35°C and 55–60°C at the breakage time for all the experiments. The Maximum temperature difference measured was 56.99°C on the 12 mm glass surface, and the corresponding maximum thermal strain found was 482 × 10−6 mm/mm. The maximum heat release rate was found to be approximately 200 kW. Maximum heat flux was found in the range of 10.33 kW/m2 to 21.14 kW/m2. A correlation was also developed using the least square method for all the thicknesses, which is well correlated with the glass thickness per unit length.

Investigation of NiAl Intermetallic Compound Formation in Layered Ni–Al‐Thin Film Systems by Grazing Incidence X‐Ray Absorption Spectroscopy

NiAl bi‐ and trilayers are prepared by alternating evaporation of aluminum and nickel on float glass substrates under high vacuum, with individual layer thicknesses between 20 and 100 nm. The samples are subjected to an annealing procedure to temperatures of up to 300 °C in vacuum, and the structural changes induced by the heat treatments are followed by in situ grazing incidence X‐ray absorption spectroscopy experiments at the Ni K‐edge. The results show that the elemental metallic deposits are stable up to 180 °C, while a slow formation of the intermetallic NiAl compound occurs at temperatures above 200 °C. No additional reaction intermediates are detected. Linear combination fits employing spectra of face‐centered metallic Ni and body‐centered NiAl as references allow to quantify the contributions of the respective phases as a function of the temperature and the depth in the multilayer. In general, an increase of the phase fraction of the intermetallic NiAl phase is detected. While the deposited elemental metals cannot completely be transformed into this intermetallic compound for the Al–Ni bilayer system even after prolonged annealing at 240 °C, the analysis of the spectra of the Al–Ni–Al trilayer suggests almost complete conversion to NiAl with body‐centered‐cubic structure.

Study on the Characteristics of Molten Glass in a Float Glass Process with a New Structure.

Glass is one of the most common materials in society, and the float glass process is the main production method of glass used at present, which involves adopting a melting furnace with a single cooler. However, this structure has been difficult to fit to the requirements of modern glass production, such as producing multiple types of glass and large-scale production. Therefore, a large-tonnage float glass melting furnace with a double cooler is studied, which is rising in popularity in the glass sector. The aim of this paper is to clarify the characteristics of the new glass furnace. A numerical simulation technique is applied to analyze the thermal and flow characteristics of molten glass in the new structure so as to clarify the feasibility of production by checking the temperature distribution and flow field of the molten glass. The results show that the new structure also exhibits flow behavior similar to the original structure in the branch line. Due to the addition of the branch line, the stability of the temperature is improved, with a 60 K and 43 K difference between the surface and bottom in the main and branch lines, respectively. Similar stability is shown in the flow field, specifically low acceleration in the cooler (0.006 m/s2). The bubble clarification time is about 2700 s, less than the 3000 s required for flow. The parameters of the branch line meet the requirements of glass production. In theory, a glass-melting furnace with a double cooler has the capacity to produce two types of glass.

Effects of Moisture Content on the Radiative Properties and Energy-Saving Performance of Silica Aerogel Windows.

The thermal insulation performance of windows is crucial for energy-efficient buildings. Windows are typically the weakest part of the building envelope, regarding thermal insulation. Due to its excellent thermal insulation and high transparency, silica aerogel shows great promise as a window material. However, moisture can impact the effectiveness of the aerogel, leading to poor visibility and reduced thermal insulation. This study simulated a silica aerogel with varying moisture levels using the combination of diffusion-limited cluster aggregation, discrete dipole approximation, and Monte Carlo methods. The effects of the moisture content, thickness, porosity, and particle size on thermal conductivity, solar transmittance, and haze were analyzed. Visual properties of the aerogels were also considered. The energy consumption of a 30 m2 room under different climates was simulated using TRNSYS to assess the energy-saving potential of silica aerogel glass. The findings indicate that a higher moisture content leads to decreased solar transmittance and increased thermal conductivity of aerogels. Silica aerogel glass is more energy efficient than single-layer float glass, with the dry aerogel performing better in cold climates but worse in hot climates. This study provides insights for designing aerogel glass that optimizes solar transmittance and thermal insulation to enhance building comfort and energy efficiency.

Ultra Miniaturization and Transparency Frequency Selective Surface for Dual Band ISM Shielding

This article presents an ultraminiaturized frequency selective surface (FSS) for shielding 2.4 GHz and 5.8 GHz (ISM) signals. The unit cell size is 0.056λ × 0.056λ (λ is the free space wavelength at the first resonant frequency). It has smaller cell size and good transparency compared to previous ISM band studies, and transparency at 54%. The proposed FSS design consists of a wall structure and a compound square loop with 2.4 GHz and 5.8 GHz resonance frequencies for ISM band coverage. This FSS structure was fabricated on float glass with a dielectric constant of 8 by a photolithographic process. The fabricated FSS structure has excellent angular stability and polarization stability, which is further verified by experimentation. An easy optimization method is proposed to tune the independent resonant frequencies by optimizing the geometries individually. This FSS is interpreted by filtering through surface induced currents and equivalent circuit models. A prototype of the proposed FSS is fabricated and measured. The simulation results are in good agreement with the measured results. The proposed FSS has polarization insensitivity and 80∘ angle stability and is suitable for solving the EMI problem in ISM band.

Experimental study on full-scale glass roof panels with embedded laminated connections under the short-term and long-term loading

This experimental study covers a problematic of full-scale roof panels with four embedded laminated point connections under two types of loads - short-term loads on intact panels, and long-term uniform loads after the fracture of a thermally treated glass pane. Two types of panels consisting either of fully tempered, or heat strengthened glass plies in combination with float glass, were tested, and a specific type of Ethylene Vinyl Acetate foil was used as the interlayer. The first part of the study investigates short-term load bearing capacity of horizontally suspended panels. The load was applied in several loading and unloading cycles until the collapse of any connection. The second part of the study is focused on the residual load-bearing capacity of the roof panels after a partial failure, whereas a first step, the thermally treated glass plies were intentionally fractured. The long-term part of the experiment was performed within 65 days. During this period, the load was increasing until a collapse of any connection. In both types of experiment, a difference between specimens with fully tempered and heat strengthened glass was observed. In the short-term part of the experiment, the specimens with fully tempered glass failed in two steps and therefore, showed considerable post-failure load bearing capacity. On the other hand, the specimens with heat strengthened glass collapsed suddenly in one moment giving no post-failure capacity. In the long-term part of the experiment, the resistance of specimens with heat strengthened glass was higher than the resistance of specimens with fully tempered glass. Therefore, both types of panels might find its purpose in real applications if the needs of the structure are properly considered.

Glass a Scarce Commodity

The adoption of glass reuse in construction faces challenges due to higher costs and more perceived risks compared to new glass. This conflicts with the goal of a circular economy. To challenge this status quo, this article explores a hypothetical scenario where glass becomes a scarce commodity. What if the float glass production process ceases to exist due to energy resource depletion, raw material scarcity, or carbon budget constraints? In such a context, glass reuse will be crucial. This article discusses the design, logistics and quality related challenges of reusing float glass, including structural integrity and energy performance considerations. Additionally, this article investigates the potential for glass reuse by analysing ongoing and future research, supply-demand dynamics, innovative building design, the concept of the future glass factory, and the re-evaluation and promotion of regulatory frameworks. To promote glass reuse, the article emphasizes customization over standardization. Considering the diverse dynamics of projects, from high-rise buildings to terraced houses, and varying regional construction requirements, solutions must be specific and adaptable, rather than standardized.

Re-Glass: Product Development Pathways for Post-Consumer Glass

Our research examines the viability of recycling soda lime glass from post-consumer Insulated Glass Units (IGU), mixing various types of architectural glass cullet and fusing them into flat plates by using electric kilns. Those kilns operate at lower temperatures than standard float glass production, which significantly reduces manufacturing emissions. The research outcomes suggest the potential for near-site operations, reducing transportation logistics, costs, and emissions. Strength and emissivity tests were performed on the recycled glass samples, to assess challenges arising from various production parameters including: glass types, processing methods, annealing temperatures and schedules, cullet sizes and distribution. These explorations offer high-level perspectives for developing post-consumer glass solutions driven by emissions and logistics primarily, and tectonics secondarily, exploring the cost-effective diversion of glass products from landfill to generate solutions staying within the built environment. The research examines performance aspects of recycled glass as emblematic of sustainability in design and underscores the role (and implications) of texture in architectural materiality. Performance and viability are weighted with considerations for the US market (hauling distances, energy grid emissivity across states, market culture, labor rates, incentives, or lack thereof). This exploration proposes innovative avenues for integrating distinctive, sustainable recycled glass as a hallmark into architectural frameworks.

Laboratory Demonstration of Grating Embedded Mirrors for Single-Shot Heliostat Optical Metrology

Abstract Concentrated solar power (CSP) plants need to monitor the surface slope error of thousands of heliostats with sub-milliradian accuracy. Large numbers of heliostats installed in harsh environments mean that measurement speed and durability are key design considerations for metrology systems. We present a compact, accurate, and high-speed heliostat slope error metrology system that is robust to the harsh environmental conditions at CSP plants. The system is composed of (1) grating embedded mirrors (GEMs), which have multiple different phase diffraction gratings written within a glass mirror substrate, and (2) a compact optical system, the diffractive auto-stigmatic Hartmann camera (DASHCam). Using focused ultrafast laser pulses, we write phase gratings within second-surface float glass mirror without damaging the reflective coating on the backside. The gratings direct a small fraction of incident light to non-specular directions, which the DASHCam senses from a virtual center of curvature to measure the mirror slopes at each grating patch. In a CSP plant, each heliostat mirror would be a GEM, and the DASHCam would rapidly measure slope and canting errors during heliostat manufacturing, installation, or operation. We fabricated 0.1 meter-diameter GEMs with 24 grating patches, built a prototype DASHCam system, and tested the system repeatability and accuracy by comparing against a Fizeau interferometer. Our results show, in a laboratory environment, 24μrad root mean square (RMS) measurement repeatability and 47μrad RMS accuracy, with single-shot image capture. The combination of GEMs and DASHCam is a promising metrology approach that could lead to improved optical accuracy of heliostats throughout their life cycle. This work serves as a proof of principle for this system.

New insights into the interpretation of the results of four point bending tests on float glass

The four point bending test is one of the most commonly used and standardised tests to determine the mechanical properties of materials. For its use on float glass there are both the ASTM C158-02R17 and European EN 1288-3:2001 standards. However when testing float glass the results tend be a statistical muddle. This impacts the reliability of the design strength of float glass determined using four point bending tests. In an attempt to resolve this problem a series of four point bending tests were conducted which were designed to be more systematic than those previously reported in the literature and which use newly developed digital microscopy techniques for pre- and post-test analysis. By systematically testing, the test results can be divided into different groups based on air side, Sn side and source of failure, allowing the data to be divided into clear and separate statistical groups. Secondly the results can potentially be used to validate the lower bound glass strength theory proposed by Ballarini et al. (J Eng Mech 142(12):04016100, 2016). The glass specimens were industrially cut, ground, chamfered and flat polished on the long sides. Specimens were checked using advanced digital microscopy before and after testing. The results suggest that uni-modal Weibull behaviour only applies above a critical failure stress. Failures at stresses below this critical failure stress as a group have a separate and steeper Weibull slope. This supports Ballarini’s theory for a lower bound failure strength although there are important differences between the air side and Sn side of the specimens which this theory does not currently allow for. These differences seem to be inherent to the differences between the glass and the Sn sides. The results also show that the strength of cut, ground, chamfered and flat polished glass can be high but that inconsistency in process control and the irregular occurrence of surface failures are the main causes for the statistical spread. Digital microscopy can reliably measure the quality of the various surfaces and intersections of surfaces of a glass specimen but there is no absolute relation between the size of a detected defect and the probability that this defect actually leads to failure.

Experimental Behavior of Solar Still Using Mixed Oxides Mn-Fe/Silicone Resin Composite as Selective Solar Absorber

In this research, the optical properties of a black pigment of mixed Mn-Fe oxides synthesized by the precipitation method dispersed in silicone resin at different concentrations for use as a solar absorber in a two-slope passive solar still were evaluated. The transmittance of different thicknesses of float glass with 0.1% Fe2O3 was also studied for use as a condenser in the construction of the solar still. Regarding the pigments, the absorbance and spectral emittance were evaluated, the floated. With the above information, both the absorbent surface and the condensers were optimized to propose the best design of the solar still. The novel hybrid material used as a selective coating in the still, which corresponds to 2.3% Mn-Fe mixed oxides, exhibited a high solar absorbance of 91.82% and a relatively low infrared thermal emission of less than 57.22%, as well as good stability to the corrosive and hot environment of the solar still, in addition to great durability over time and in real operating conditions. The float glass with the highest transmittance corresponds to a thickness of 3 mm and an average transmittance of 82.57%. The built prototype was characterized by obtaining the temperature profiles of the absorber and condensers, thermal efficiency, production and water quality. The prototype has a thermal efficiency of 29.6%, requiring only energy from the sun for its operation. The water produced by this device becomes an option for human use and consumption in accordance with current official standards, allowing supply in communities that do not have access to drinking water but have access to seawater or waters with high hardness.

Diffraction, spectroscopic and microscopic studies of the sand from the amber deposit

QUARTZ sand plays a crucial role in the production of float glass, as it is the main source of silicon dioxide, which is necessary for the production of glass. The research was conducted on two samples of QUARTZ sand from the Oleksiivka amber deposit. The aim of this study was to investigate the morphology and chemical composition of QUARTZ sand samples. The identification methods such as infrared spectroscopy, X-ray diffraction, and electron microscopy with the Energy Dispersive X-ray Spectrometer detector were presented. Applied methods allowed to identify crystalline phases and non-crystalline components of the tested samples.

On the structure and properties of hydrothermally toughened soda–lime silicate float glass

On the structure and properties of hydrothermally toughened soda–lime silicate float glass

A novel industrial process situation awareness model based on multi‐time scale dynamic feature fusion with applications to float glass manufacturing

AbstractModern industrial manufacturing processes often focus on the changes of performance indicators and the evolution of operation conditions. However, the dynamics of variables are vague within processes and even more difficult to be characterised across different processes. The time‐series dynamic characteristics of the different scales among variables, processes, and production cycles develop and transfer with changes in parameters, equipment, and processes. It is difficult to accurately show the quality index and operating condition trend at the same time. To solve these problems, a situation awareness (SA) framework integrating multi‐time scale dynamic features for manufacturing processes is proposed. First, data are condensed and reconstructed through the denoising long short term memory autoencoder to reveal the time series dynamic characteristics to get neighbourhood features which contain features among neighbourhood samples. Second, the neighbourhood features divided into window blocks are fused into the stage features by statistical analysis. Finally, a multi‐scale isometric convolution network is designed to extract the local and global features, which can effectively show the development of dynamic features on a long time scale, and profoundly describe the influence of full cycle features on variables and operating conditions. The proposed model is verified on the real data set of a float glass manufacturing process, and the SA model can well predict the future trend of long time series.

Design and Tests of Structural Post-Tensioned Glass T-Beams

Glass manifests superior properties with high strength and transparency although it may not be considered as a commonly used structural material. This study targets to improve the structural performance of glass by post-tensioning; a series of T-shaped glass beams are tested to develop a proper and safe design. Traditionally, glass is widely used in buildings as windows where its brittleness and strength capacity are not significant. Architects prefer to use glass in the structural field because of aesthetics, recyclability, and transparency. Although there is more demand for the usage of glass as a structural material, a common fear of its brittle nature and lack of research about its structural behavior have mostly hindered it. Since glass is a brittle material and has high compressive strength in the order of 400 to 800 MPa and lower tensile strength (40 to 120 MPa), post-tensioning to target distributed loads is investigated to increase its fracture capacity and even obtain a post-cracking ductile behavior. In this study, several material tests are conducted to confirm the theoretical mechanical properties of glass. After obtaining the bending and compressive strength of the glass, Finite Element Models (FEMs) of the T-beams were generated and analytical hand calculations were conducted. The tests of T-shaped annealed (float) and tempered (toughened) glass beams with and without post-tensioning were conducted. The results of the experiments were compared with the analytical hand calculations and FEM results. A favorable outcome of this study is that float glass’ post cracking strength has been drastically increased and a ductile post-cracking performance is obtained. Tempered glass has a brittle response but with much higher strength, with about 4 times the capacity of annealed glass T-beams

Experimental Behavior of Solar Still Using Mixed Oxides Mn-Fe/Silicona Resin Composite as Selective Solar Absorber

The optical properties of a black pigment of mixed Mn-Fe oxides synthesized by the precipitation method, dispersed in silicone resin in different concentrations as well as different thicknesses of float glass with 0.1% of Fe2O3 for use in the construction of a two-slope passive solar still. Regarding the pigments, the spectral absorbance and emittance were evaluated, the x-ray diffraction patterns were obtained to know their crystalline structure and their morphology was studied through surface profilometry, in addition the spectral transmittance for the different samples of float glass was evaluated. With the previous information, both the absorbing surface and the condensers were optimized to propose the best design of the solar still. The hybrid material used as a selective coating in the still, which corresponds to 2.3% Mn-Fe mixed oxides, exhibited a high solar absorbance of 91.82% and a relatively low infrared thermal emission, less than 57.22%, as well as good stability to the corrosive and hot environment of the solar still, in addition to great durability over time, real operating conditions. The float glass with the highest transmittance corresponds to a thickness of 3 mm and an average transmittance of 82.57%. The built prototype was characterized by obtaining the temperature profiles of the absorber, water column and condensers, thermal efficiency, production and water quality. The prototype has a thermal efficiency of 27%, requiring only energy from the sun for its operation and the product water is distilled water, free of salts, of great potential value for human use and consumption in accordance with current official standards.

Three-dimensional modeling of impact fractures in brittle materials via peridynamics

Accurate prediction of the impact fracture behavior of brittle materials is crucial in various industries. The paper employs the peridynamic method to model the penetration and damage in brittle materials during impact. The proposed three-dimensional peridynamic impact fracture model (3D-PDIFM) overpasses other numerical models by adopting a new computational technique to couple the impact collisions of different types of projectiles with the peridynamic method. Moreover, the 3D-PDIFM is highly efficient in impact fracture simulations by focusing on the effects of the projectile without simulating its particles, thereby saving more computational efforts. Validation through comparison with experimental measurements and observations ensures that the 3D-PDIFM accurately represents the real-world impact fracture behavior of brittle materials. The paper also highlights the efficiency of the 3D-PDIFM in comparison to traditional mesh-based numerical simulations. Therefore, the 3D-PDIFM can be significant for practical engineering applications as efficient simulations can save time and computational resources. Using the validated model, the impact fracture behavior of PMMA under various conditions, such as changes in panel thickness, impact area, and projectile velocity, is investigated. This analysis gains more insights into how these factors affect the brittle material's response to impact. Moreover, the impact fracture behaviors of tempered glass and float glass panels are examined under different conditions of impact loadings. This study also explains the penetration and impact fracture phenomena in brittle materials. Overall, using the 3D-PDIFM as a modeling and simulation tool can help engineers and researchers analyze the behavior of glass panels under various impact scenarios, thus allowing for optimization of design parameters to improve impact resistance.

Evaluation of substrate temperature role on the structural, morphological, optical, and mechanical properties of magnetron sputtered Cu2Se thin films

Copper Selenide (Cu2Se) thin films were deposited on a float glass substrate using magnetron sputtering with a radio frequency (RF) source at a power of 70 W and by varying substrate temperatures (Tsub) from 50 °C to 400 °C with an interval of 50 °C. The influence of the Tsub on the morphological, structural, and mechanical characteristics of Cu2Se thin films was investigated using the Grazing Incidence X-ray diffraction (GIXRD), Raman spectra, Field Emission Scanning Electron Microscopy (FESEM) combined with energy-dispersive spectroscopy (EDS) and Nanoindentation. The results of the GIXRD analysis suggest that the cubic Cu2-xSe phase could be observed when the deposition took place at Tsub of 50 to 200 °C. However, for the films that were deposited at temperatures higher than this range, i.e., from 250 °C to 400 °C, the elements Cu and Se formed an intermediate phase. Raman bands assigned at 261 cm−1 confirm the cubic-Cu2Se phase. The average grain size measured from FESEM images increase with varying Tsub from 50 °C to 400 °C with a value of 230 nm to 320 nm. The variation in the Tsub results in the evolution of the microstructure and EDS shows the variation in the stoichiometric ratio of deposition. The energy of the band gap decreases with an increase in Tsub, leading to the overlapping of energy levels. The nanoindentation tests show that the hardness dropped as the Tsub increased from 50 °C to 400 °C. The Cu2Se film deposited at Tsub 50 °C had the highest hardness value of 1.91 ± 0.47 GPa.

Analysis of the effects of vickers indentation-induced defects on the strength and probability of failure of float glass during biaxial flexure testing

This study examines the impact of indentations on the strength of float glass. Using the Vickers indentation method with loads of 1N and 10N, we created defects at varying distances from the point of contact. Biaxial flexure tests revealed that indentations with 1N at 18mm decreased the strength, while those with 10N and shorter distances from the point of contact increased the strength. Weibull distribution analyses showed a correlation between the load, distance, and the Weibull modulus, highlighting the influence of defect size on the probability of rupture.