Float Glass Research Articles

Experiment and simulation study of erosion mechanism in float glass due to rhomboid particle impacts

A coupled FEM-SPH numerical model is established to investigate the erosion behaviors of float glass subjected to angular particle impacts. The accuracy of the model is validated by comparing with measured data onto float glass erosion experiments. The model is then used to simulate single rhomboid particle impact on float glass surfaces under various conditions including impact velocity (20~110 m/s), impact angle (60~90 deg) and initial orientation angle (−10~50 deg). The results show: (1) similar to ductile material, the critical orientation angle marking the maximum kinetic energy loss is also observed for brittle material like float glass. Under the critical impact condition, the kinetic energy loss of rhomboid particle is up to 98.69% and 94.82% during vertical and incline impact respectively; (2) The formation and propagation of radial cracks and lateral cracks are determined by the combined effects of impact angle and orientation angle, and the brittle crater formed by the backward impact is wider and shallower than that of forward impact; (3) The behaviors of brittle splashing (i.e., fragments and chips) are successfully reproduced by the model, and the particle rotation behaviors after the impact significantly influences the direction of splashing stream which is less influenced by the impact angle; (4) The impact velocity determines the extent of material damages, and has little influence on the rotation behaviors of particle. Under the condition of constant kinetic energy, the size of particle (1.0~5.0 mm) has little effect on the erosion mechanisms in terms of crater depth, crater profile, splashing flow pattern and crack propagation.

A novel investigation study on float glass hole surface integrity & tool wear using Chemical assisted Rotary ultrasonic machining

To alleviate the alarming surface integrity defect (chipping) and tool wear issues, new machining technique has been introduced. First time, an attempt has been made by hybrid the ‘Rotary ultrasonic machining’ and ‘Chemical etching process’ that pioneer as ‘Chemical assisted Rotary ultrasonic machining’. In this work, authors have investigated a novel study to explore the float glass’s drilled hole surface integrity and tool wear. The mechanism behind the hole surface integrity and tool wear is also discussed. The results pointed that the Chemical assisted Rotary ultrasonic machining (CRUM) gives slightest chipping size (0.32 mm) using abrasive coated hollow tool of 6 mm diameter over the 5% HF acid dipped float glass specimen. However, coz of highly chemical reacting behaviour of HF acid with the tool material, it is deteriorated. Thus more research needed to be carried for the tool selection. Finally, authors recommended that the Chemical assisted Rotary ultrasonic machining is having a vibrant future.

Experimental investigation of cutting temperature during drilling of float glass specimen

In today’s industrialization, hard and brittle material such as float glass are widely used in various applications such as micro-fluidic devices, bio-medical parts, automotive glass, and optical lenses. Due to its difficult-to-machine characteristic, drilling of float glass leads to defects related to drilled hole quality. These defects exemplify as chipping, crack and surface roughness. All these defects are directly depend upon the temperature which could affect the drilling quality. Hence, authors tried to investigate the influence of cutting temperature of float glass specimen using rotary ultrasonic drilling. The experimentation is performed at two conditions with constant value of ultrasonic amplitude (20 μm), feed rate (6 mm/min) and spindle rotation speed (5000 rpm). These conditions are without coolant and with-coolant drilling. It is noticed that maximum cutting temperature reached with coolant drilling is 50.56°c and without coolant is 62.11°c. Consequently, it is revealed that drilling with coolant (water) should be adopted to improve the hole quality. Since, it reduced the formation of stresses during drilling operation which are induced due to rise in temperature. Microstructure images are carried out to visualize the hole quality.

Forensic float glass fragment analysis using single-pulse laser ablation inductively coupled plasma time of flight mass spectrometry

A proof-of-concept for a novel Single-Pulse-LA-ICP-TOFMS based method is shown for the forensic investigation of float glass fragments.

Introduction to the research

Innovations in glass technologies and engineering over the last decades have altered the way we perceive glass. Combining transparency, durability and a compressive strength exceeding that of concrete and even structural steel, glass has evolved in the engineering world from a brittle, fragile material to a reliable structural component with high compressive load-carrying capacity. At present, the structural applications of glass in architecture are constantly increasing, yet with a considerable geometrical limitation: although glass’s fabrication boundaries have been continuously stretching so far, glass structures are still dominated by the limited shapes which can be generated by the combination of the virtually 2-dimensional, planar elements produced by the float industry. Whereas glass panels in float production can stretch more than 20 m in length, the width is restricted to 3.21 or 4.5 m and the maximum commercial thickness is only 25 mm (Lyons 2010; Schittich et al. 2007; Patterson 2011). Cast glass can overcome the design limitations imposed by the 2-dimensional nature of float glass. By pouring molten glass into moulds, solid 3-dimensional glass components of almost any shape and cross-section can be obtained1. Such objects can be shaped to form repetitive units for free-form full-glass structures that do not buckle due to their slender proportions, thus taking full advantage of the high compressive strength of glass; a solution little explored so far. Discouraging factors such as the meticulous and time-consuming annealing process required, the to-date non-standardized production, and the corresponding high manufacturing costs, have limited cast glass to only a handful of realized architectural applications. Consequently, there is a lack of engineering data and a general unawareness of the potential and risks of building with cast glass as a structural material. The loadbearing function of cast glass in architecture remains an unmapped field. Scope of this research is to explore the structural potential and limitations of solid cast glass components and introduce cast glass as a promising construction material in architecture, indicating both the potential and limitations of this alternative production process for glass in buildings. To achieve this, the research focuses on the development and experimental validation of two new design concepts for selfsupporting envelopes made almost entirely of cast glass components: adhesively bonded and interlocking cast glass components.

Material compositions and production methods for solid cast glass components

Glass can be made by different manufacturing processes and by numerous of varied recipes that in return provide the material with different properties. Owing to their workability in lower melting temperatures and the corresponding decreased manufacturing costs, soda-lime and borosilicate glass types are preferred for cast glass applications in structures. Glass can be cast in two ways: primary and secondary casting. In primary casting, glass is molten from its primary raw ingredients, whereas in secondary casting, solid existing pieces of glass are re-heated until the (semi-) liquid mass can flow and be shaped as desired. The main process of primary casting is hot-forming (melt-quenching) and of secondary casting is kiln-casting. The principal difference between the two methods, besides the initial state of glass, is the required infrastructure. In hot-forming, molten glass from a furnace is poured into a mould and is then placed in another, second furnace for annealing. In contrast, kiln-casting employs a single kiln for the melting of the (already formed) glass into the moulds and for the subsequent annealing process and requires lower operating temperatures. In both methods the annealing process is similar. The annealing schedule is influenced by numerous factors that cannot be easily simulated as a complex non-linear time dependent multi-variable analysis is required. As a result the annealing schedule of large 3-dimensional cast units is commonly empirical. Different mould types, disposable or permanent, can be used for casting glass objects. The choice of mould mainly depends on the production volume and desired level of accuracy of the glass product, and is in practice usually cost and time driven. Currently, there is no standard to determine the design strength of solid cast glass objects for structural applications in architecture. Based on the assumption that the increased volume of cast glass can lead to a higher amount of randomly distributed flaws in the mesostructure, the bending strength of cast glass is expected to be comparable but slightly less than that of standard float glass.

Abrasive water jet drilling of float glass and characterization of hole profile

The applications of glass are tremendous since prehistoric period. Glass being brittle, amorphous material, it is highly difficult to carry out its machining using conventional methods. As abrasive water jet is a versatile non-traditional machining process, the current study uses Abrasive Water Jet (AWJ) for drilling glass. Among the various types of glass, most fragile glass type—float glass is used for study. Appropriate process parameters are used for machining based on the results and observations from preliminary experimentation. Also the Taguchi design is selected to carry out experimentation for all the possible combinations. The evaluation process of the drilled hole is carried out using optical profile projectors—to view the hole profile; Coordinate Measuring Machine (CMM)—to measure circularity and cylindricity; and Scanning Electron Microscopy (SEM) to observe the chipping and cracks developed during machining. Based on the deviation in hole profile, kerf analysis is carried out. Based on all the input and output parameters quantified, Analysis of Variance (ANOVA) is carried out to determine the most influential parameters. Finally based on the results obtained, for the experimented conditions and equipment used, Abrasive water jet drilling process is not recommended for drilling smaller diameter holes in float glass.

Probabilistic considerations about the strength of laminated annealed float glass

Laminated structures are parallel (or redundant) systems, i.e. failure occurs when all the elements (glass plies) reach, in cascade, the ultimate limit state. Following the failure mode approach, the reliability analysis is consequent to the identification of all possible rupture modes of the glass plies, where each mode is identified by the sequence of collapse, synthetically schematized as an event-tree. The event “structural failure” is the union of all the possible failure modes. The static theorem of limit analysis guarantees that the more the structure is divided into load bearing elements acting in parallel, the safer it is, but this conclusion holds only for ideal ductile systems. For brittle glass it is often assumed that lamination gives a beneficial contribution in all cases, but glass strength is affected by a size effect in terms of area, because surface micro-cracks govern the overall capacity of the material. Taking this into account, we show through the failure mode approach, under some simplifying assumptions, that lamination can decrease the strength of a plate made of annealed glass, since the higher the number of plies is, the larger is the surface area under tensile stress. This finding focalizes the attention on the importance of an accurate characterization of the size effect in glass strength.

Studies on thermally induced microstructural modifications and electrical conductivity in glass RPC detector materials

Asahi and Saint Gobain float glass Resistive Plate Chamber (RPC) detector materials are subjected to isochronal annealing treatment. To explore the temperature induced microstructural modifications in glass RPC detector materials, Positron annihilation lifetime spectroscopy (PALS), X-Ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic investigations were performed. The positron lifetime parameters viz., o-Ps lifetime (τ3) and void size (Vf) increased significantly due to thermal expansion of SiOSi bonds in the regular tetrahedral structure of glass network. The significant increase in the void size of glass RPCs above 150 °C annealing temperature is attributed to the thermal vibrations of SiOSi bonds. The temperature induced electrical conductivity and activation energy is correlated with the positron lifetime parameters in both the float glasses. The thermally induced structural changes at higher annealing temperature are more in Saint Gobain glass than Asahi float glasses.

Building integrated photovoltaic at NEST – Preliminary test bedding results

This paper presents preliminary results on the visual and energy assessment of colored photovoltaics modules installed at the Meet2Create unit of the NEST pilot- and demonstration site at Empa in Dübendorf. The installation contains mono-crystalline PV modules with three different types of front glass (float, silk and satinated) and three different patterns printed on them (shutter, curve and ornament). Each printed PV module and three unprinted reference modules are monitored separately over a period of one year. With float glass, the visual appearance is dominated by reflections of the environment, an disturbing effect that does not appear with the matte and brighter satinated glass, where the colored print pattern remains visible across all viewing angles. Interestingly, the energy output is relatively similar. Compared to the unprinted reference PV modules, the losses with float, silk and satinated glass are 68, 75, and 72% respectively. While the different print patterns do not yield a significant difference. Satinated glass is thus an interesting alternative to the common float and structured front glass when visual appearance and energy efficiency matters.

Preparation of a self-cleaning glass using solutions of titanium fluor complexes

The object of research is silicate glass with a nanostructured coating of titanium oxide (in the anatase modification), which is noted for photocatalytic activity and, as a result, acquires the ability to self-clean under ultraviolet irradiation. The existing industrial method of applying such a coating is carried out by the pyrolytic method, but it is effective for large-scale production, and is carried out for large-sized products from sheet float glass. For the production of small-scale, or piece products, it is not justified. This applies to products of complex configuration, and especially hollow. In the case there are methods of coating from the liquid phase. First of all, the sol-gel method. The classical such method requires titanium alkoxides, which are of high cost, as precursors. Cheaper and more flexible is the method of coating from solutions of titanium fluorine complex compounds. Ammonium hexafluorotitanate is used as a precursor, but it is expensive. It is proposed to modify the chain of chemical transformations, namely: to use the cheaper and more affordable ones as primary precursors. It is proposed to obtain it artificially, using the bifluoride method. During the study, ammonium bifluoride NH 4 HF 2 and titanium oxide TiO 2 are used, which, according to the proposed synthesis method, form (NH 4 ) 2 TiF 6 , its appearance is confirmed by X-ray phase analysis. Fluorination of titanium oxide Ammonium bifluoride occurred at a temperature not exceeding 200 °C. Fluorination is accompanied by the release of only water vapor and ammonia. A photocatalytic coating is obtained on float glass samples by precipitation of the anatase crystalline phase from an aqueous solution of (NH 4 ) 2 TiF 6 . The presence of anatase is confirmed by X-ray phase analysis. The size of crystalline formations does not exceed 15-20 nm. The self-cleaning ability is evaluated by the hydrophilicity test of the glass and the spectral characteristics of the coating in the ultraviolet range. Due to this, it is possible to obtain a self-cleaning coating on glass, which, in comparison with similar known ones, is not inferior in quality and has the following advantages: low cost and availability, absence of harmful emissions, complies with the principles of «green chemistry».

Investigation of thermal stability, optical properties, phase and chemical composition of transparent conductive tin oxide films deposited by pyrolytic method on silica float glass

The object of research is transparent conductive coating based on fluorine doped tin oxide deposited on silica float glass by the pyrolytic method. However, both in the manufacturing process of such a coating and in the process of its operation, degradation of its electrically conductive properties is observed. This may be due to changes in the structure of the coating under the influence of certain technological and operational factors, namely: process temperature, holding time, gas environment during the application and operation of a transparent electrically conductive coating. Studies have confirmed a significant increase in electrical conductivity. They also found a slight decrease in the transmittance of transparent oxide-tin films obtained with the introduction of ammonium fluoride as a dopant during the pyrolysis of 1M alcohol solutions of Sn2+ and Sn4+chlorides and are widely used as precursors for the content of such coatings. So, with a ratio of Sn4+/F=10 in working solutions, a minimum of specific surface resistance was fixed at 32 Ohm/m2. At the same time, a decrease in the value of the averaged transmittance in the optical wavelength range of 0.2-6.0 μm by 51 %, and in its visible part (0.4-0.8 μm) by 11 %. It is shown that thermal degradation of the coating is a significant factor in increasing the resistance values both in the technological process and during operational impacts. The results obtained indicate that reheating to temperatures above 450 °C leads to the appearance of the phenomenon of thermal degradation of the electrically conductive properties of the coating. So, during a 1-hour exposure at a temperature of 550 °C, the increase in specific surface resistance increases by 2 times and is fixed at 68 Ohm/m2 after complete cooling. Repeated heating cycles with the indicated parameters lead to a significantly lesser effect, which may indicate stabilization of the processes that occur during thermal destruction of the electrically conductive coating.

Fabrication of Custom-Designed and Cost-Effective Spin-Spray Pyrolysis Unit

In this paper, an efficient, spin-spray pyrolysis unit is designed and constructed for the deposition of oxide thin films. The system is an effective combination of two independent techniques such as spin and spray methods. The rotation of the substrate by keeping the spray nozzle stationary makes the system unique. The system allows the decomposition of the solution before reaching the substrate. Spin-spray pyrolysis unit is capable of coating thin films on different substrates like float glass, FTO coated glass, and Aluminum coated glass, Teflon, and kepton, of dimensions up to 4-inch diameter, any contour and scalable to industrial applications. Metal oxides like Al2O3, GZO, ZnO etc., can be coated for many applications such as solar cells, thin-film transistors, sensors, etc. The elements required for construction of spray pyrolysis units are a heater, spray nozzle, thermocouple, solution feeding unit, airflow assembly, substrate rotator, and exhaust assembly. The elements of the system are discussed in accordance with the cost estimation. The working principle of each element of the system is explained in a separate block diagram. The system is optimized for deposition of ZnO thin films on a glass substrate and is characterized. The thin-films can be used for development of TFT’s, heaters, thermistors, piezo-electronics devices, sensors, antireflection coatings and solar cell.

Evaluation and comparison of methods for forensic glass source conclusions

Float glass, a common type of glass used in windows and doors, can be important evidence in the investigation of a crime. If fragments are optically indistinguishable, they may be distinguishable in their chemical compositions, which can be measured using inductively coupled mass spectrometry with a laser add-on (LA-ICP-MS) [14]. If the measurements are “similar enough” then the recovered fragment is indistinguishable from the crime scene glass [1]. Recently, Park and Carriquiry [10] proposed using machine learning methods to establish probabilistic source conclusions for glass, and found that these methods have lower classification error than traditional methods. Using an experimental database of glass elemental concentrations to simulate different forensic scenarios, we examine the results from two different classifiers to understand why learning algorithms appear to outperform traditional methods when making source conclusions for forensic float glass questions. By analyzing each step in the recommended ASTM decision process, we conclude that the standard ASTM method is not the optimum and that more data are required to determine a better comparison rule for source conclusions based on the chemical makeup of float glass.

Resolving local dynamics of dual ions at the nanoscale in electrochemically active materials

Electrochemical conversion is typically studied at macroscopic scale, and it is quite challenging to probe local electrochemistry at the nanoscale, especially those involving multiple ions. Through a series of atomic force microscopy experiments, we demonstrate that two competing ionic strains arising from molar volume changes and electrochemical dipoles in a dual-ion system can reveal themselves in distinct relaxation behavior, enabling us to decouple their respective contributions and thus measure local diffusivity along with activation energy. Using soda-lime float glass as a model system, we observe a fast relaxation corresponding to diffusion of Na+ and a slow relaxation associated with electrochemical dipoles formed between Na+ and non-bridging oxygen. Assisted by simulations, we determine the local diffusivity of 5.64×10−16m2/s and activation energy of 0.55eV for Na+ at 100 °C. The study provides a powerful tool to resolve local dynamics of dual ions, which can be applied to study a variety of complex energy conversion and storage systems.

Investigation on the adhesive mechanism of mounting brackets formed by injection molding with a safety glass insert

ABSTRACT To address deficiencies in traditional coating and adhesive processes for installing auto safety glasses, mounting brackets for auto safety glass were formed by the insert injection molding process via employing an insert. Specifically, float glass was used as the insert, Chemlok CH456 and CH489 were utilized as the glass primer, and soft polyvinyl chloride (PVC) was adopted as the material for injection molding. The adhesive force of the mounting brackets was measured, and the adhesive behavior of the mounting brackets was characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results indicated that the adhesive force of the mounting brackets obtained by insert injection molding can be as high as 1027 N. The results showed that the primer located in fracture regions was torn from PVC and the glass. Double-interface adhesion was found between the glass, the primer, and PVC. In particular, the primer and the glass surface formed strong adhesion by mechanical locking, diffusion existed between PVC and the primer, and the diffusion depth was greater than 10 μm. This process greatly shortens the production cycle of the mounting brackets for auto safety glass and greatly improves the adhesive quality of the mounting brackets.

Analytical and Experimental Investigation of Ultra Wideband Channel Characteristics in the Presence of Door/Window Glass

This paper presents ultra-wideband channel characteristics in the presence of float glass slab as obstacle of varied thickness (4 mm, 8 mm, 12 mm, 19 mm) in an indoor environment. Two different sets of measurements are performed related to variation in the Tx–Rx antenna position and rotation of the glass slab at angles varying from 0° to 90° to mimic the glass door/window movement. The channel characterization of various Tx–Rx links are carried out by analyzing various parameters such as RMS delay spread, peak magnitude of the power delay profile and received signal amplitude. Different direct path, partial and total obstructed path situations are observed depending on the position of the Rx antenna, rotation angle of the glass slab and also the position of the Tx–Rx antennas with respect to the glass slab. Results indicate higher multipath and RMS delay spread for glass edge scattering and direct through glass propagation. Decrease in signal strength is more prominent for 12/19 mm glass thickness in comparison to 4 mm glass sheets for partial NLOS and NLOS scenarios. For LOS situations, channel parameters for various glass thickness show similar range of values and are comparable with the scenario when no-glass in present.

Effect of Mechanical Activation on the Heat of Fusion of a Conventional Batch Used for the Manufacture of Float Glass

ABSTRACTAn initial mixture of raw materials (batch) typically used for the manufacture of conventional soda-lime float glass was subjected to a mechanical activation process for 30 or 60 minutes in a planetary ball mill. An intensification of the chemical reactivity of the batch, which was directly related with the increase in the milling time, was observed. This accelerated the chemical reactions that took place during the batch melting process between sodium, calcium and magnesium carbonates and other components of the mixture, which happened at significantly lower temperatures with respect to the batch without mechanical activation. The heat of fusion of the batch, estimated using a methodology previously reported in the literature, indicated that the mechanical activation given to the initial mixture of raw materials decreased the energy consumed during the batch melting. This was also evidenced by a decrease in the temperature at which the release of CO2 ended, which was considerably larger than that previously reported in the literature based solely on the decrease in the particle size of a batch of similar composition achieved by dry sieving.

Characteristics of Temperature changes and Stress of Float Glass under Heat Radiation

Characteristics of Temperature changes and Stress of Float Glass under Heat Radiation

Cut edge of annealed float glass: crack system and possibilities to increase the edge strength by adjusting the cutting process

The edge strength of annealed float glass is an essential aspect in engineering design. A common problem in engineering applications is the failure of the edge due to thermally induced stresses. The edge strength of annealed glass is affected by cutting, further processing and handling. Thermally treated glass exhibits higher edge strengths, but may show optically negative effects such as anisotropy and roller waves. In case of covered edges, e.g. insulating glass covered by framing, an enhanced strength of the cut edge is desirable. This paper presents results showing that enhanced strength of the cut edge is feasible and reproducible using regular cutting technology. A large part of this contribution deals with the crack system resulting from the cutting process. A deep understanding of this is essential for the relationship between cutting parameters, damage and edge strength. In addition to optical microscopic analyses, confocal microscopy and indentation tests have been carried out. The influence of different cutting process parameters on the edge strength was investigated within the scope of extensive analyses by the Fachverband Konstruktiver Glasbau e.V. This allowed to adjust selected process parameters so that the edge strength could be reproducibly enhanced. In this contribution the latest results of these investigations are presented. In addition, the correlation between microscopic optical characteristics and the mechanical strength as expressed by the macroscopic fracture stress is described.