Translucent Coatings Research Articles

Translucent Skylights from Falconnier Glass Blocks

Construction technologies go through several stages: emergence, improvement, decline and revival. Falconnier glass block technology, which was in demand at the very beginning of the 20th century, is now being revived again. Hand-blown and hollow inside, Falconnier glass blocks were widely used for glazing windows, greenhouses, lighting stairs, but of particular interest is their use as a material for glazing translucent coatings of roofs and atriums. Quite often, glass bricks could be found in blank fire walls. In most cases, glass blocks were used for the purpose of zoning spaces while maintaining daylighting, as well as in technical rooms. But Falconnier glass blocks were also used for glazing front facades. But in the mansion of the Tambov manufacturer Aseev, built in 1904–06, a unique cylindrical vault was made from this material, covering the large span of the central living room. On the territory of Russia, it was apparently the only structure of complex configuration made of Falconnier glass blocks. The structure was lost and needs to be restored. According to the results of research, its close analogue is the translucent coating of the atrium of the town hall in Zurich, which is perfectly preserved and, in fact, is very close to the historical design of the lost part of the skylight in M.V. Aseev’s mansion. At the moment, there is every reason to believe that the lost Falconnier technology was practically restored by enthusiasts, which will expand the possibilities in the field of restoration of monuments at the turn of the 19th‑20th centuries. Both of these factors – the existence of a similar constructive solution and the restored technology for manufacturing glass blocks – open up opportunities for recreating a glass barrel vault that completes the atrium of M.V. Aseev’s mansion, which is currently a museum complex.

СИЛОВЫЕ ИСПЫТАНИЯ ПЛЕНКИ ЭТФЭ

Studies of mechanical properties of ethylene-tetrafluoroethylene (ETFE) film they are relevant for wide application in the construction of translucent coatings in the climatic conditions of Russia, especially in the Arctic zone. Power tests were performed for a film with a thickness of 250 microns on an INSTRON bursting machine, as well as with a uniformly distributed load at positive and negative temperatures. The initial modulus of elasticity according to GOST 34370-2017 was established, which was 1090 MPa. Three loading stages have been identified for the calculations of translucent coatings. In the elastic stage of operation of the ETFE film, the average modulus of elasticity was 35.8 MPa, in the elastic-plastic stage – 1.78...2.71 MPa and in the plastic stage of operation – 0.06...0.086 MPa. Force tests of a membrane made of ETFE film with a thickness of 250 microns on a power triangular frame with a uniformly distributed load of up to 8,577 kPa did not lead to rupture of the membrane at any positive (+15 ...+18 оС) not at subzero temperatures (-23...-29 оС). Repeated mechanical damage (cuts) of the membrane under a load of 8.50 kPa at a temperature of -26 оС also did not lead to its rupture. The deflections of the membrane at positive temperatures reached 84 mm, at negative temperatures – 58.2 mm. Power tests of the ETFE film have shown its ultra-high strength characteristics, which makes it possible to widely use it to create a comfortable environment in structures erected in the Arctic and other territories of Russia when localizing production in Russia.

Eco-Friendly Superhydrophobic Composites with Thermostability, UV Resistance, and Coating Transparency.

Despite the market demand for biofiber assemblies endowed with superhydrophobicity being huge, the current approaches to their production are complicated, time-consuming, and even pose a serious threat to the environment. Here, we report a simple surface treatment strategy to prepare environmentally friendly superhydrophobic biofiber composites. The obtained samples have certain UV resistance properties, which are mainly determined by the titanium dioxide (TiO2) dosage. Additionally, the sample has excellent thermal stability, and the contact angle is maintained at 153.26° after heat treatment at 140 °C for 1 h. Quite encouragingly, thermal annealing of samples can transform translucent coatings into transparent structures and increase the tensile strength. The results also showed that this strategy could be integrated into the mass production process of other biofiber components as coating, such as coated paper, pulp boards, cotton gauzes, tissues, and so forth. Due to the facile preparation and environment-friendliness, this sustainable paper-based product can be used in diversified applications: packaging and storage of liquid food, protection of ancient books, UV- and rain-proof materials, and teaching demonstrations relevant to bionics, among others.

Polymeric number average molecular weight in submicron films as a tool for the manipulation of water phenomena in translucent coatings

Absorption and desorption properties of poly(ethylene glycol) diacrylate (PEGDA) have seen to greatly vary depending on the molecular weight of the polymer, suggesting a dependence of the wetting phenomena on its molecular weight. Here, two sets of polymeric submicron films (140 and 190 nm) were fabricated by free radical polymerization using Phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide as the photoinitiator, and PEGDA (Mn 250 or 575). The films were spin coated on glass substrates to study their wetting phenomena by dynamic contact angle analysis. All films were characterized in terms of their thickness and transmittance. PEGDA Mn 250 films (Film-250) decreased the sliding time of water drops when compared to a clean glass substrate because of a decrement in the liquid-solid interface area. Nonetheless, when using PEGDA Mn 575 films (Film-575), an improvement in the adhesion forces between the coating and the drop of water was observed, avoiding the drop to slide down the substrate and leading to its later evaporation. In addition, Film-575 drastically changed their morphology after water exposure, while Film-250 remained the same. These characteristics are of special interest in environments where a response towards small amounts of water is desired, or where water evaporation is craved. Copyright © 2018 VBRI Press.

Recommendations For Restoration Of Historical Transparent Coatings In Pushkin Museum

Due to the intensification of historical buildings restoration works that are cultural monuments and related to architectural monuments, numerous questions arise about the possibility of increasing the efficiency of translucent structures, including their energy efficiency, using modern innovative technologies. The cost of competent reconstruction of windows and lanterns with the preservation of historical elements is much higher than the cost of standard modern structures, as a result of which there are numerous examples of barbaric illegal replacement of historical windows with modern ones. This not only spoils the appearance of buildings, but also contradicts federal laws (with all the ensuing consequences). Earlier, NIISF RAASN carried out multifactorial field studies of historical translucent coverings of a cultural monument of federal significance – the main building of the Pushkin Museum, on the basis of which their inconsistency with modern requirements for such structures was established. According to the technical assignment and the project for the reconstruction of the building, 13 options were proposed for the possible restoration of these coatings. To assess the proposed options, a comprehensive computer simulation and corresponding calculations were carried out in accordance with the certified software package “WINDOW TECT”. On the basis of the conducted examinations and computer calculations, optimal solutions were proposed for the restoration of historical translucent coatings of the main building of the Pushkin Museum, providing for the preservation of the original elements of metal structures and ensuring an increase in the thermal characteristics of the lantern and side lamp.

Lysine‐Functionalized Gibbsite Nanoplatelet Dispersions for Nonisocyanate Polyhydroxyurethane Nanocomposites and Translucent Coatings

AbstractThe lysine functionalization of ultrathin γ‐Al(OH)3 single‐crystal nanoplatelets (ly‐gibbsite) having an average thickness below 100 nm and a width ranging between 0.5 and 1.5 µm renders them organophilic and enables their agglomerate‐free dispersion in nonisocyanate polyhydroxyurethane (NIPU) thermosets prepared by amine cure of polyfunctional cyclic carbonates. Whereas most other nanoparticles drastically increase viscosity even at very low content, NIPU processing tolerates up to 40 wt% ly‐gibbsite without impairing its uniform dispersion. The amine groups of ly‐gibbsite can react with cyclic carbonate groups of NIPU to afford interfacial coupling. Contrary to the NIPU composites containing corundum and spherical gibbsite particles, ly‐gibbsite/NIPU nanocomposites exhibit substantially higher stiffness as reflected by high Young’s modulus up to 9500 MPa. Moreover, ly‐gibbsite/NIPU coatings remain translucent even at high ly‐gibbsite content when the nanoplatelet length is below 1 µm. As verified by transmission electron microscopic imaging of coatings, the ly‐gibbsite nanoplatelets are aligned parallel to the surface. At high ly‐gibbsite content, NIPU thermosets are rendered flame retardant in the absence of halogen and other flame retardants. The NIPU coatings tolerate the addition of aluminum flakes to produce metallic NIPU varnishes.

Engineering exterior translucent coatings with the use of profile glass and composite materials

The paper raises certain questions concerning the use of structural glass (glazing) in external vertical enclosures of modern construction systems, pointing to the need for combining composite materials, especially composite foam, in translucent enclosures, which helps dramatically reduce the weight of external panels while improving their heat and sound insulation performance. It also emphasizes the relevance of energy efficiency at the building operation and building construction stages, as energy efficiency is not only the heat saving performance during building operation, but also a high effectiveness of the construction technology.The novelty of the study lies in engineering a wall panel possibly combining two materials — profiled glass and composite foam. The paper not only details the panel design, but also describes the manufacturing technology and the envelope arranging processes with two wall panel attachment methods and related joint assemblies. Based on a number of scientific publications, the handling mechanisms are discussed suitable for different ways of coupling the structural elements — wall panel and floor slab. Focusing on box-type structural glazing, the authors stress the need for further study involving other types of structural glass (channel shaped, ribbed, trimmed) to create multicomponent wall panels for a variety of regional climate conditions.

The effect of silver nanoparticles on the black-stain resistance of acrylic resin for translucent wood coating application

Translucent coatings applied to wood that is used for exterior applications often fail because of photodegradation and colonisation by black-stain fungi. This paper reports the effect of silver nanoparticles on the black-stain resistance of acrylic latex coatings. Acrylic latexes that contained various concentrations of silver nanoparticles were mixed with a commercial acrylic resin. The formulations were then applied to red pine (Pinus resinosa) sapwood, which was later evaluated for fungal resistance to Aureobasidium pullulans, Sclerophoma pityophila, and Eppicoccum nigrum. Latexes with silver nanoparticle concentrations as low as 0.03% (total coating formulation weight) were able to limit S. pityophila and E. nigrum growth, while higher concentrations were needed to limit the growth of A. pullulans. The influences of silver nanoparticles on the optical properties of the coating (i.e., colour, opacity, and gloss) were evaluated. It was demonstrated that the addition of silver nanoparticles to the formulation does not compromise the development of a translucent coating.

Adaptation Of Architectural Solutions Of Large-Span Translucent Coverings Of Football Stadiums Of Russia To Work In The “Heritage” Mode

Requirements for architectural and construction solutions of large-span translucent coverings of football stadiums imposed on the basis of the current legislation of the Russian Federation and the relevant standards of the International Federation of Football Associations, based on experience in the design, construction and operation of the 2018 FIFA World Cup facilities, are considered. The reasons for the requirement changes, caused by the transfer of ownership of sports facilities to subjects of the Russian Federation, and a change in the nature of the objects operation in the "Heritage" mode, are established. The diversity in the understanding of the tasks of a stadium architectural organization by specialists, involved in match arrangements, and the operational service, responsible for the break-even use of the facility as a multifunctional cultural and sports entertainment complex are identified. Priorities for adaptation of architectural solutions of large-span translucent coatings stadiums to changing conditions are established. Data on peculiarities of projects of Grand Sports Arena “Luzhniki” in Moscow and “Yekaterinburg Arena” are presented. The available experience in operation of the named structures since the completion of their reconstruction is generalized. The prospects of development of architecture of large-span translucent coverings of stadiums in the future are proposed.

Influence of Ambient Temperature, Wind Speed, Emissivity, and Average Working Temperature of Light-Absorbing Heat-Exchange Panels of Flat-Plate Solar Water-Heating Collectors on Their Thermal Losses Through Translucent Coatings

This article presents the results of computational experiments aimed at determining the influence of the ambient temperature ( $${{t}_{a}}$$ ), wind speed (v), average working temperature ( $${{\bar {t}}_{{avw}}}$$ ), and emissivity of light-absorbing heat-exchange panels (LAHPs) $$\left( {{{\varepsilon }_{p}}} \right)$$ on their thermal losses through the translucent coating (TC) of the case of flat-plate solar water heating collectors (FSWHC) with a single-layer TC.

INTEGRATION OF HEAT TRANSFER OF LIGHT-TRANSFER COATINGS IN SOLAR ENERGY

The use of solar energy is an environmentally friendly, energy-saving process. Putting into operation of solar installations improves the ecological situation of the region due to a decrease in emissions of pollutants, which include products of combustion of traditional types of energy - organic fuel. On the energy efficiency of using some materials as a translucent coating, which covers the thermally insulated casing, in which the solar collector is located, there are scattered information in technical literature. The use of other materials and obtaining generalized dependences of the heat flux density and efficiency on temperature when the coolant flow rate in a solar collector varies depending on the capacity of a single or multilayer translucent glass or synthetic film coating. In a solar installation mounted on the roof of one of the boarding houses located in the South of Ukraine, several heat-insulated coatings were installed on several insulated buildings in which solar collectors were placed: one layer of glass; two layers of glass; three layers of glass; one layer of plastic film; one layer of glass and one layer of plastic film; two layers of plastic film; one layer of glass and two layers of plastic film. During operation, the temperatures were measured: the coolant inside the solar collector, the air between the solar collector and the translucent coating, the walls and bottom of the housing. The experiments were carried out with a change in the volumetric flow rate of the coolant from 0,5 to 3,5 m³ / h. According to the experimental data, the calculation of the density of heat fluxes and the efficiency of all the above listed versions of translucent coatings was carried out, the dependences of the densities of heat fluxes and efficiency on temperature were constructed. All dependences are approximated by equations and correlation coefficients are determined. The generalized dependences of the heat flux density and efficiency on the temperature in the solar collector are obtained when the volumetric flow rate of the coolant varies from 0,5 to 3,5 m³/ h, depending on the transmittance of various translucent coating options.

Influence of Meteorological Factors on the Thermal Loss Coefficient of Light-Absorbing Heat Exchange Panels of Flat-Plate Solar Water Heating Collectors through Transparent Coatings of Their Casings

The results of computational studies aimed at determining the coefficient of thermal losses of light-absorbing heat-exchange panels (LAHP) of flat-plate solar water-heating collectors (FPSWHC) through their translucent coatings (TC) are presented. The calculations take into account the effect of free and forced convection on the external surface of the TC, as well as on the convective heat transfer coefficient and the FPSWHC tilt, the atmospheric transparency, and the air humidity on the total heat transfer coefficient from the external surface of the TC to the environment. An example is given to test the proposed approach for practical use to determine the values of $$~\alpha _{{{\text{i}}{{{\text{n}}}_{{{\text{w}} - {{c}_{1}}}}}}}^{\Sigma }$$ , $$\alpha _{{{\text{ex}}{{{\text{t}}}_{{{{c}_{2}} - {\text{amb}}}}}}}^{\Sigma }$$ , and their convective and the radiant components, and also the degree of their influence on the value of $${K}_{{{{c}_{{{\text{w}} - {\text{amb}}}}}}}^{~}$$ .

Application and artificial weathering performance of translucent coatings on resin-treated and dye-stained beech-wood

Abstract Beech wood boards ( Fagus sylvatica L.) modified with thermosetting N -methylol melamine (NMM) and phenol-formaldehyde (PF), partly with a dye added (NMM-dye, PF-dye), were coated solely with a translucent water-borne acrylic binder and a formulation containing the same binder and UV-protective agents (UV-PA: UV absorbers, HALS). The aim was to improve the weathering performance and to maintain the colour stability of the modified wood. The applicability of the coating on the modified boards was similar to that of untreated control boards, but the drying times were prolonged. Capillary water uptake of modified, uncoated and coated boards was clearly lower than that of respective controls. Dry and wet adhesion of the coating film and the proportion of wood fracture were higher on the modified substrates than on the controls, but no clear difference was observed among the modified boards. The colour stability during weathering depended in the modification and coating. Untreated and NMM modified samples became lighter, while PF-modified boards turned darker. The weathered coating on the modified boards, particularly with PF resin, showed less blistering, flaking and cracking than that on the controls. The coating on all resin-modified boards maintained higher adhesion during weathering than the controls. UV-PA stabilised the colour and adhesion on all boards compared to the single binder formulation. The study shows that wood modification with NMM and PF improves the weathering performance of wood coated with acrylic coatings. Combined modification with staining can diversify the optical appearance of wood coated with translucent finishes.

Silica-Polyethylene Glycol Hybrid Organic-Inorganic Solid Electrolytes By Sol-Gel for Lithium-Ion Battery Applications

Among the many applications proposed for solid electrolytes, their employment in lithium-based secondary batteries has the greatest impact in terms of technology and market potential [1]. Rechargeable thin film microbatteries have recently become the topic of widespread research for use in low power applications and energy storage systems for electric devices [2]. Common rechargeable batteries are based on a liquid electrolyte, which implies that there are several restrictions for their design and size due to the available separators and liquid electrolytes. Secondly, these liquid electrolytes carry the inherent risk of leakage [3]. Therefore the need for all-solid-state microbatteries arises, which can facilitate miniaturization, will create more flexibility for the design of stand-alone microelectronic devices [4]. In battery applications, the ionic conductivity is of paramount importance as the power density of the device depends on the electrolyte performance. Lithium-ion solid electrolytes offer many advantages such as ease of manufacturing, immunity from leakage, suppression of lithium dendrite formation, elimination of volatile organic liquids and mechanical flexibility. However, the main problem in achieving the expected applications is their low ionic conductivity [5]. The suitable combination of inorganic and organic materials into hybrid nanostructured thin film electrolytes could result in an interesting combination of properties able to substitute the liquid electrolyte [6]. This work reports on the preparation and structural properties of hybrid ionic conductor silica (SiO2)-Polyethylene glycol (PEG n ) using a sol-gel approach. The materials were prepared by sol-gel method: Tetraethoxysilane (TEOS), Polyethylene glycol (PEGn) and Bis(trifluoromethane)sulfonimide lithium salt LiN(CF3SO2)2 (LiTFSA) in a desired [O]/[Li] ratio (where oxygen considered are only those of the ether type), have been used as precursors. Several compositions were studied in order to evaluate the ionic conductivity and electrochemical stability. The thus obtained solutions were cast onto silicon moulds to obtain the desired solid membranes, having a translucent appearance, with thicknesses about 0.1 cm. The optimization of the processing parameters leads also to homogeneous and translucent coatings of few microns. The structural characterization was carried out by FTIR, Raman and RMN. The electrical properties of the materials have been determined by Electrochemical Impedance Spectroscopy (EIS). The lithium transference number and electrochemical stability window were analyzed to evaluate compatibility with the lithium metal and other possible electrodes. Ionic conductivities about 10-5 S/cm at room-temperature has been found for [O]/ [Li] = 10.6 and PEG400/TEOS = 1.0 ratios (Figure 1).

On determining the solar radiation absorption factor for translucent coatings of flat solar plants

A correct expression is proposed to determine the solar radiation (SR) absorption factor for translucent coatings (TCs) of flat solar plants.

Numerical calculations of heat engineering parameters of a solar greenhouse dryer

The results of numerical simulation to determine the optimum volume of a thermal storage water heater in a solar greenhouse dryer are presented. A CAD (computer-aided design) model is created for the given installation by simulating the heat transfer processes with the aid of the Solid Works Flow Simulation software. The given CAD model consists of a concrete foundation and a steel frame in which translucent coatings made from two-layer polycarbonate sheets 6 mm in thickness with an air gap between the two layers are attached. The north wall is made of bricks with size and thickness of 2 × 4 m2 and 0.4 m, respectively. The front surface has an angle of inclination 39.53° with respect to the horizontal surface for the maximum incidence of solar radiation to its surface. All the geometrical dimensions of the solar greenhouse dryer were selected on the basis of the allocated platform for the solar drying installation 3 × 4 m2 in size. It is shown that the optimum volume of the heat storage tank for the present installation is 500 L.

Effective scaled heat loss coefficient for translucent coatings of flat plate water-heating solar collectors

We study how heat losses through translucent coatings are affected by the partial absorption and heat transformation of the total solar radiation passing through the transluscent coatings of flat plate water-heating solar collectors; the radiation is incident on the frontal surfaces of the translucent coatings of their casings and is reflected from the antireflective surfaces of the heat-exchange panels of diffuse solar radiation collectors; the radiation is incident on the rear surfaces of the considered translucent walls. To allow for this factor in thermal engineering calculations for the “antireflective heat-exchange panel-translucent coating” system of the considered type of flat plate solar collectors, we introduce the effective coefficient of heat loss from the antireflective surface of a heat-exhange panel via the given translucent coating. We propose a calculation technique and the corresponding formula for determining the effective heat loss coefficient through the transluscent walls of flat plate water-heating solar collectors and present a practical calculation example for determining its value.

Strength of sheet glass, supported along the perimeter, under a concentrated load

The results of experimental and theoretical studies of the behavior of sheet glass under a concentrated load are presented. A method and program for analyzing sheet glass when designing translucent structures, coatings and overlays have been developed.

Secondary spectral standards based on Fabry-Perot etalon

We discuss the possibility of using a Fabry-Perot interferometer as a source of the comparison spectrum for calibrating the wavelengths in the spectra of astronomical objects. For low dispersion, a Fabry-Perot etalon has been made in the form of a three-layer structure by sputtering a glass substrate in vacuum in the following order: firstly, a thin translucent layer of aluminum, then a layer of several micronthick glass, and another layer of semitransparent aluminum. For high dispersion, a Fabry-Perot etalon has been made of mica several tens of microns thick, the surface of which was sputtered with translucent coatings of aluminum. In the second case, the density of transmission peaks is higher than the density of intense spectral lines of thorium by a few dozen times.

Preparation of a colored conductive paint electrode for electrochemical inactivation of bacteria.

In this study we describe the preparation of a colored conductive paint electrode containing In(2)O(3), SnO(2), or TiO(2) for the electrochemical inactivation of marine bacteria. When each colored conductive paint electrode was immersed in seawater containing 10(6) cells/mL for 90 min, marine microbe attachment to the TiO(2)/SnO(2)/Sb electrode surface was minimal. Preparation of electrodes coated with 40% particles is shown to be more cost-effective, and because of their more translucent coatings they can be painted over with bright colors. When a potential of 1.0 V was applied for 30 min to the colored conductive paint electrode (40 wt% TiO(2)/SnO(2)/Sb) in sterile seawater, the survival ratio decreased to 55%. When 1.5 V vs. saturated calomel electrode (SCE) was applied, all attached cells were inactivated. Chlorine was not detected below an applied potential of 1.5 V. A change in pH was not observed in the range of 0 to 1.5 V. This method might be effective for preventing bacterial cell accumulation and the formation of biofilms.