Architectural Glass Research Articles

Digital image processing methods for the evaluation of optical anisotropy effects in tempered architectural glass using photoelastic measurements

In the present paper, optical anisotropy effects in architectural glass are evaluated using digital image processing. Hereby, thermally toughened glass panes were analyzed quantitatively using a circular polariscope. Glass subjected to externally applied stresses or residual stresses becomes birefringent. Polarized light on birefringent materials causes interference colors (iridescence), referred to as anisotropies, which affect the optical appearance of glass panes in building envelopes. Thermally toughened glass, such as toughened safety glass or heat strengthened glass, show these iridescences due to thermally induced residual stress differences. RGB-photoelastic full-field methods allow the quantitative measurement of anisotropies, since the occurring interference colors are related to the measured retardation values. By calibrating the circular polariscope, retardation images of thermally toughened glass panes are generated from non-directional isochromatic images using computer algorithms. The analysis of the retardation images and the evaluation of the anisotropy quality of the glass is of great interest in order to detect and sort out very low quality glass panes directly in the production process. Therefore, in this paper retardation images are acquired from different thermally toughened glass panes then different image processing methods are presented and applied. It is shown that a general definition of exclusion zones, e.g. near edges is required prior to the evaluation. In parallel, the limitations in the application of first-order statistical and threshold methods are presented. The intend of the investigation is the extension of the texture analysis based on the generation of Grey Level Co-occurrence Matrices, where the spatial arrangement of the retardation values is considered in the evaluation. For the first time, the results of textural features of different glass pane formats could be compared using reference areas and geometry factors. By reduction of the original image size, the computation time of textural analysis algorithms could be remarkably speeded up, while the textural features remained the same. Finally, the knowledge gained from these investigations is used to determine uniform texture features, which also includes the pattern of anisotropy effects in the evaluation of thermally toughened glass. Together with a global evaluation criterion this can now be implemented in commercial anisotropy measurement systems for quality control of tempered architectural glass.

Large scale architectural glass slumping process - challenges and limitations

Large scale architectural glass slumping process - challenges and limitations

Influence of the deposition temperature on the optical and electrical properties of TiN film by spectroscopic ellipsometry

Abstract Low emission (Low-e) films are widely used in modern architectural glass. In this presentation, spectroscopic ellipsometry (SE) between 1.12 and 2.75 eV (wavelength range: 450–1100 nm) was used to investigate the temperature dependence of dielectric function of TiN films. A Drude-3Lorentz dispersion model was selected and the results show both the real part e 1 and the imaginary part e 2 increase with the deposition temperature increasing. The structure and performance of the obtained TiN samples were characterized by X-ray diffraction, Raman, scanning electron microscope, UV/Visible (UV/VIS) spectrophotometer and Hall measurements. Combining the measured results, it is found that with the deposition temperature increasing, the grain size of TiN film changed from 15.4 nm to 17.4 nm and the surface becomes rougher. The concentrations of titanium and nitrogen vacancies decrease with increasing deposition temperature. A combined Drude-3Lorentz model was used to analyze the dielectric and optical properties of the obtained TiN films. It is found that TiN samples exhibit typical Drude-Lorentz like behavior in the visible and near-infrared (NIR) regions. The results were verified by Hall measurements and UV/VIS measurements. With the deposition temperature increasing, the reflectivity increased in the NIR region and a peak reflectivity of about 93% can be obtained at the wavelength of 1000 nm. With the deposition increasing, the infrared emissivity decreased. The infrared emissivities of the TiN film deposited at 673 K are 0.26 and 0.08 at wavelength of 2.5 μm and 25 μm, respectively, which shows TiN may be a good candidate for low-e film.

High Performance Power Supplies for Plasma Materials Processing

Integrated circuits, flat panel displays, solar panels, architectural glass, high resolution camera and many other products are landmarks of the $21^{st}$ century. All of these different everyday objects have one thing in common - they are manufactured using plasma processing techniques. The aim of this paper is to introduce this silent hero of modern industry, to a broader audience. An evaluation is made of common types of power converters within the scope of plasma processing applications, while the key requirements and future challenges for such power supplies are discussed.

Environmental Stability of High Temperature Molten Vitreous Residue of Hazardous Waste

Vitrification technology is one of the harmless treatment methods for hazardous waste containing heavy metals and other harmful substances, converting solid waste into vitreous residue with amorphous structure by high temperature melting. In this paper, we propose the acid dissolution rate in acidic environment to characterize the environmental stability of molten vitreous residues. We have tested six high temperature melting residues from different enterprises. The results of our experiments show that the higher the degree of vitrification, the lower the acid dissolution rate, and most of them are similar to basalt, quartz and architectural glass. This work demonstrate that the vitreous residue produced by high temperature melting has high stability and low leaching toxicity. Vitrification technology can solidify heavy metals and other harmful substances in the dense three-dimensional structure of glass state.

Aerosol‐deposited Al2O3/PTFE hydrophobic coatings with adjustable transparency

AbstractWith the wide range of requirements for architectural glass, such as transparency, opacity, and hydrophobicity, there is a need to address the issues in the complexity of convention methods. Thus, considering functionality and applicability in various architectural windows, hydrophobic alumina/polytetrafluoroethylene (Al2O3/PTFE) composite layers with transparency or opacity were transferred to commercial architectural glass using a facile aerosol deposition (AD) process. We successfully fabricated hydrophobic coating layers with high transmittance (only a 0.03% difference from sheet glass) by optimizing the PTFE content in Al2O3 using solution‐based synthesized powders to enable a uniform surface topology. The opaque hydrophobic Al2O3/PTFE coating layers exhibit a transmittance of approximately 0% with excellent hydrophobicity of 130°. Remarkably, this opaque film was successfully employed onto a large deposition area, curved substrate, and micro‐patterned regions. It is believed that our AD‐prepared composite layers have great potential for architectural glass in terms of economic feasibility and versatility.

Magnetron sputtering

Magnetron sputtering developed rapidly in the 1980s for semiconductor, hard coating, and architectural glass applications. While the general operating principles were well known, subtle issues relating to cathode material, operating parameters, and deposition processes were only empirically understood. A sequence of magnetron measurements is described, which helps develop a more general understanding. The plasma is mostly conventional but is strongly perturbed by the large fluxes of energetic, neutral atoms sputtered from the cathode, which alter the gas dynamics as well as the discharge impedance. These studies have led to practical innovations, such as collimation and ionization of the sputtered atoms, which have been widely used for semiconductor manufacturing applications.

Experimental study of the dynamic response of architectural glasses under vented explosion loads of methane–air mixtures

In order to study the dynamic response characteristics and anti-deformation ability of different architectural glass under the action of gas explosion, four types of architectural glass, namely tempered glass, laminated glass, hollow glass and float glass, were selected as test samples. The explosion test is carried out by changing the thickness of the glass specimen, the gas concentration and the explosion venting material and other factors under the condition of fixed support on four sides. The results show that different types of architectural glass have different anti-explosion capabilities, so the failure mode and crack distribution under the action of gas explosion are different. With the increase of the thickness of the structure layer, the anti-explosion ability of different building glasses is improved. When the concentration of methane is close to the stoichiometric concentration or the strength of venting material is higher, the dynamic response of the glass specimen is more violent and even destroyed. At the same time, the finite element software LS-DYNA was used for numerical analysis of the single-layer glass test model. The failure mode and crack distribution obtained were basically consistent with the test results, which verified the reliability of the numerical simulation method.

Production and provenance of architectural glass from the Umayyad period.

A large assemblage (n = 307) of architectural glasses (tesserae and windows) from the early 8th-century Umayyad residential site at Khirbat al-Minya was analysed by laser ablation inductively coupled plasma mass spectrometry. Trace element patterns are essential to establish the provenance of the base glass, while the comparative evaluation of the colouring and opacifying additives allow us to advance a production model for the manufacture of glass mosaic tesserae during the early Islamic period. The primary glass types are Levantine I and Egypt 1a, as well as a few older, reused tesserae, and Mesopotamian plant ash glass used for amber-coloured window fragments. Chemical data revealed fundamental differences in the colouring and opacification technologies between the Egyptian and Levantine tesserae. Co-variations of lead and bismuth, and copper, tin and zinc in the Egypt 1a tesserae provide first evidence for the production of different mosaic colours in a single workshop, specialising in the manufacture of tesserae of different colours. No such trend is apparent in the Levantine samples. Red, cobalt blue and gold leaf tesserae were found to be exclusively made from a Levantine base glass, indicating that the generation of some colours may have been a specialised process. The same may apply to the amber-coloured window glass fragments of Mesopotamian origin that exhibit very unusual characteristics, combining elevated copper (2% CuO) with an excess in iron oxide (5% Fe2O3). These findings have significant implications for the production model of strongly coloured glass and the exploitation of resources during the early Islamic period.

Blue-blocking antireflective coatings based on a selective absorber in Cr2O3 media

Antireflection (AR) coatings allow increased substrate transmission and reduce surface reflection over a specific wavelength range. We proposed a blue-blocking (BB) AR coating that allows maximal visible-light transmittance while minimizing the transmittance of blue light, owing to selective absorption. Admittance diagrams of BB Cr2O3 / SiO2 coatings and traditional AR Ta2O5 / SiO2 coatings were shown to demonstrate that small absorption affects the reflectance much less than it affects the transmittance. Therefore, by controlling the degree of absorption, the lower residual reflection can be obtained by optimizing the thickness of different layers of the overall stacked structure. Coatings were fabricated using remote plasma sputtering to meet the requirements of low residual reflectance (<1.16 % ), high visible-light transmittance (exceeding 90%), and short-wavelength transmittance attenuation by ∼20 % . These promising results indicate that this type of BB coatings is a good candidate for vision protection applications, such as eyeglasses, desktop and mobile digital screens, and solar control films used in architectural glass.

Relationship Between Advertising and Performance of Micro and Small Architectural Glass Companies in Nairobi County, Kenya

This study was on the relationship between advertising and performance of micro and small enterprises architectural glass companies in Nairobi County, Kenya. The study was anchored on three theories: Attention, Interest, Desire, and Action (AIDA) theory, relationship marketing theory, and the push theory. The study adopted a correlational research design and sampled 124 employees working in Micro and Small Enterprises (SMEs) in nine architectural glass manufacturing firms. Questionnaires and interview schedules were used to collect primary data. The study found out that all aspects of advertising influenced performance of Micro and Small Enterprises architectural glass companies. The study concluded that there was a strong and positive correlation between advertising and the performance of micro and small architectural glass companies. Therefore, the study recommended that micro and small architectural glass companies in Nairobi County should continually embrace advertising because it promoted performance and growth of revenue in the firms. Keywords: advertising, performance, micro and small enterprises, architectural glass companies DOI: 10.7176/EJBM/12-27-09 Publication date: September 30 th 2020

Application of the Glass Failure Prediction Model to Flat Odd-Shaped Glass Using Finite-Element Modeling

Abstract Model building codes and standards in the United States find their bases in a probabilistic model of glass load resistance (LR). In general, architectural flat glass design predicated on t...

Stained Glass and the Victorian Town: Rochdale Library, Museum, and Art Gallery

Between 1850 and 1920 Britain saw an explosion in the use of decorative glazing in all types of public buildings. The enormous impact and significance of decorative glass produced for the palaces of commerce, civic pride, and recreation in cities and towns throughout Britain, with its connotations of opulence and luxury, has so far been largely overlooked. Rochdale, part of Greater Manchester, was a booming industrial town in the nineteenth century due to its cotton industry and became home to much impressive architecture, such as the Rochdale Library, Museum, and Art Gallery (collectively, now Touchstones), originally opened as a public library in 1884. The library contained a wealth of stained glass, now removed, which comprised imagery of significant local and national figures including a window dedicated to women authors. The art gallery and museum still contains glass by the important Manchester firm run by W. J. Pearce, which can be found on the staircase and by the entrance. The combination of mouth-blown and machine-made glasses used in the schemes reveals new ways of thinking about glass in architecture of the period and the role of stained glass as a relevant contemporary art form.<br>

Experimental Validation of Water Flow Glazing: Transient Response in Real Test Rooms

The extensive use of glass in modern architecture has increased the heating and cooling loads in buildings. Recent studies have presented water flow glazing (WFG) envelopes as an alternative building energy management system to reduce energy consumption and improve thermal comfort in buildings. Currently, commercial software for thermal simulation does not include WFG as a façade material. This article aims to validate a new building simulation tool developed by the authors. Simulation results were compared with real data from a scale prototype composed of two twin cabins with different glazing envelopes: a Reference double glazing with solar-control coating and a triple water flow glazing. The results showed a good agreement between the simulation and the real data from the prototype. The mean percentage error of the indoor temperature cabin was lower than 5.5% and 3.2% in the WFG cabin and in the Reference glazing one, respectively. The indoor air temperature of the WFG cabin was 5 °C lower than the Reference one in a free-floating temperature regime when the outdoor air temperature was 35 °C and the maximum value of solar radiation was above 700 W/m2. WFG has energy-saving potential and is worthy of further research into the standardization of its manufacturing process and its ability to increase building occupants’ comfort.

Experimental investigation of rupture and dispersion characteristics of float glass subjected to vented explosion loads of methane–air mixtures

ABSTRACT The high-speed flying debris from architectural glass in a gas explosion poses a great security threat to personnel and building safety. In this paper, the damage characteristics of float glass under gas explosion venting loads and the distribution of glass fragments are studied through field tests. The results show that the rupture and dispersion of float glass are affected by the glass thickness and type and the methane concentration. Float glass exhibits spider-web cracking, and the fragments are sharp. The main shape of the debris dispersion front is either rectangular or “drum” shaped. The initial ejection speed of the shards is affected mainly by the glass thickness. The flying debris undergoes different acceleration and deceleration processes, and two acceleration peaks occur for a methane concentration of 9.5%. The glass shards are concentrated in two main areas of the collection site, and a theoretical model of glass scattering is established based on the test results. It can provide basic experimental data for research into gas explosions and act as a reference for the anti-explosion design of building structures.

Application of the Glass Failure Prediction Model to Flat Glass Using Finite-Element Modeling

Abstract Designers of architectural glass in the United States rely on model building codes and standards for definitions of load resistance (LR) and other factors pertinent to design. Unfortunatel...

Bunshaft’s showcase: exploración sobre el edificio vitrina. Feria Mundial, 1939

&lt;p&gt;The Venezuelan Pavilion was one of Gordon Bunshaft's first projects for Skidmore &amp;amp; Owings. It was a large showcase, an airy place, a rectangle with glass walls. The exhibition was ordered between the glass perimeter and the plane on which the map of Venezuelan geography was placed. The exhibition accompanied the passage to the restaurant terrace and the tropical garden. With the success of the setup, the author architect and his team recognized the need to keep the influence of this approach in the shops and lobbies of their future buildings. For this reason, it was sought to deepen on how glazed planes improve both the internal space and the surrounding environment. Attempts have been made to reveal what Bunshaft pursues by exploring the attributes of glass sheets in his projects and reflecting on the “visual display” involved in the role of glass curtains “in and from” the pavilion. The study showed that to take heed of what is known “will be visible,” has brought a renewed perspective on the opportunities offered by the use of glass in architecture.&lt;/p&gt;

Numerical assessment of laminated cantilevered glass plates with point fixings

Cantilevered laminated glass plates, used e.g., in balconies and freestanding glass balustrades, are an example of the use of glass in modern architecture as a structural material. In order to fulfil its scope of preventing building occupants from failing out, the cantilevered plate must be able to transfer the loads imposed from the crowd pressure or by people in motion to the main structure of the building. Since a cantilevered plate is critical in the joint, the design of the connection between the glass pane and the supporting structure is of primary importance for the performance of the system. The paper investigates the behaviour of cantilevered laminated glass plates with point joints, accounting for both bolted and adhesively bonded fixings, and different designs of the joint system. The static and impact tests prescribed in the Italian standard UNI 11678 are numerically simulated and the results analysed in terms of the horizontal deflection and maximum peak stress of the glass pane. Under static loads, bonded joints reduce stress concentration and increase the lateral stiffness of the cantilevered plate in comparison to bolted fixings, but the results are highly sensitive to the stiffness of the interlayer. Increasing the vertical distance between the fixing rows is shown to have contrary effects on the stress concentration around bolt holes depending on either static or dynamic loading is considered.

Robust TiO2 nanorods-SiO2 core-shell coating with high-performance self-cleaning properties under visible light

Photocatalytic SiO2–TiO2 composite coatings with excellent self-cleaning properties have attracted much attention in recent years due to their promising applications in many areas such as automobile windshields, window glasses, and solar cell panel covers, etc. However, most of these coatings are of low self-cleaning capability in the visible light region due to TiO2 only absorbing ultraviolet light, which limit their practical application. Here, highly transparent coatings of the rod-like TiO2–SiO2 nanoparticles on glass substrates were prepared by a simple dip-coating process. The photocatalytic activity and self-cleaning property of the coatings were evaluated by photocatalytic degradation of methylene blue (MB) and methyl stearate (MS) under visible light irradiation. It was found that the coatings exhibited ~4% enhancement in the optical transmission of glass and a good mechanical stability. The as-prepared and annealed rod-like TiO2–SiO2 nanoparticle coatings show excellent self-cleaning properties. The results mean that the coatings have a high potential for self-cleaning applications in removal of organic pollutants under visible light such as solar cell panels, architectural glasses and optical devices, etc.

Application of dichroic glass in the architectural design of buildings

The application of coloured and optical glass in architecture is of great importance in terms of creating spatial dynamics and uniqueness of space. Dichroic glass is a type of glass coated with a thin layer of metal, which causes the glass surface to change in colour depending on the viewing angle. The colour of the glass depends on the incidence of different wavelengths of light passing through or bouncing off the glass surface, thus creating different effects of colour refraction. Created effects provide different possibilities in the design of buildings and improvements in the aesthetic quality of the interior space. This paper deals with the analysis and application of coloured dichroic glass in architecture and interior design.