Impact of Environmental Exposure on the Service Life of Façade Claddings—A Statistical Analysis

Façade claddings, as the outer protection layer of the building’s envelope, are directly exposed to environmental degradation agents. The façades’ orientation and their distance from the sea, among other location and protection-related factors, influence their vulnerability to climate loads, in particular wind and air humidity. These loads, as well as exposure to air pollution, affect the degradation process of claddings and the durability of façades. Therefore, studying the impact of the environmental exposure conditions on the service life of different external claddings provides useful information on their performance over time, which can support (i) decision-makers in the selection of the best façade cladding solutions and (ii) further research on the impact of climate change on building components. This study covers six types of cladding: rendered façades (R), natural stone cladding (NSC), ceramic tiling system (CTS), painted surfaces (PS), external thermal insulation composite systems (ETICS), and architectural concrete façades (ACF). Three hundred façades located in Portugal are analysed according to three main groups of variables, which characterize (i) the façades, (ii) their degradation condition, and (iii) the environmental deterioration loads and context. The statistical analysis results reveal that the environmental variables affect the cladding degradation process. South-oriented façades present lower degradation conditions than façades facing north. The distance from the sea and high exposure to pollutants add to the degradation conditions, reducing the expected service life of façades. The results reveal that claddings can be organized according to two main groups: the most durable (CTS, NSC, and ACF) and the least durable (R, PS, and ETICS) systems. This study enables a comprehensive analysis of the data, useful to draw conclusions about the influence of environmental exposure conditions on the degradation and service life of façade claddings.

Holographic Near-Eye 3D Display Method Based on Large-Size Hologram

In this paper, we propose a holographic near-eye 3D display method based on large-size computer-generated hologram (CGH). The reconstructed image with a large viewing angle is obtained by using a time multiplexing and spatial tiling system. The large-size CGHs are generated and they record the information of the 3D object from different angles. The CGHs are reproduced at different moments. For a certain reconstructed moment, three spatial light modulators (SLMs) spatially spliced into a linear structure are used to load a single CGH. The diffraction boundary angle of the reconstructed light forming each image point is equal to the maximum diffraction angle of the SLM, so the viewing angle of the image generated by the CGH is enlarged. For different CGHs, the incident angle of reconstructed light is changed. Through time multiplexing, the reconstructed images of the CGHs are combined into a reconstructed image whose viewing angle is further enlarged. Due to the large viewing angle of the reconstructed image, the proposed method has unique advantages in near-eye display. The feasibility of the proposed method is proved by experimental results.

MOSEV: a global burn severity database from MODIS (2000–2020)

To make advances in the fire discipline, as well as in the study of CO2 emissions, it is of great interest to develop a global database with estimators of the degree of biomass consumed by fire, which is defined as burn severity. In this work we present the first global burn severity database (MOSEV database), which is based on Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance and burned area (BA) products from November 2000 to near real time. To build the database we combined Terra MOD09A1 and Aqua MYD09A1 surface reflectance products to obtain dense time series of the normalized burn ratio (NBR) spectral index, and we used the MCD64A1 product to identify BA and the date of burning. Then, we calculated for each burned pixel the difference of the NBR (dNBR) and its relativized version (RdNBR), as well as the post-burn NBR, which are the most commonly used burn severity spectral indices. The database also includes the pre-burn NBR used for calculations, the date of the pre- and post-burn NBR, and the date of burning. Moreover, in this work we have compared the burn severity metrics included in MOSEV (dNBR, RdNBR and post-burn NBR) with the same ones obtained from Landsat-8 scenes which have an original resolution of 30 m. We calculated the Pearson's correlation coefficients and the significance of the relationships using 13 pairs of Landsat scenes randomly distributed across the globe, with a total BA of 6904 km2 (n=32 163). Results showed that MOSEV and Landsat-8 burn severity indices are highly correlated, particularly the post-burn NBR (R=0.88; P<0.001), and dNBR (R=0.74; P<0.001) showed stronger relationships than RdNBR (R=0.42; P<0.001). Differences between MOSEV and Landsat-8 indices are attributable to variability in reflectance values and to the different temporal resolution of both satellites (MODIS: 1–2 d; Landsat: 16 d). The database is structured according to the MODIS tiling system and is freely downloadable at https://doi.org/10.5281/zenodo.4265209 (Alonso-González and Fernández-García, 2020).

Investigating the level of Safety Considerations in Radiology Centers (North of Iran): Cross –Sectional Study

Background and Purpose Providing health care is the basic right of people(1). Diagnostic radiology is one of the main procedures in health care services and proper benefiting from this technology is brought only under well planning and management(1). Supervision of the available condition and its comparison with the recommended standards is a key role in assessing assurance from the benefit of these instruments (2). Data show that more than 80% of patients referring to these hospitals need radiology image (3).Improper service causes repetition of radiography and even wrong diagnosis, as a results threatening health of the patients (3) lack of protective barrier leads to the exposure of the staff to X-ray which is obviously carcinogen us (4). It happens that the instruments are not working properly, like of symmetry in X-ray field, defects in collimators, lack of adjusting ray field and X-ray, low quality or defective developing machine, lack of proper protective barrier, using low quality film and drugs, lack of protective barrier for children, all of which cause severe hazards for the patients and staff (4). Materials and Methods The crucial aim of medical services is to provide the public with their needs which are very important. The sensitivity of such services is to such an extent that in case of lack of care, the hazards are too high. In evaluation of health services, the first thing is to evaluate the device used. Methods, efficiency, profits and their combination for prevention and eradication of diseases are also important. Therefore to gain this goal, it is necessary the obtain results comparable with recommended standards. The purpose of this study was to access the conditions of radiology units at Mazandaran University hospitals and compare them with the standards of ICRU NCRP and ICRP. Radiology unit is the most expensive section of any hospital for its instruments, manpower and space provided. In a study conducted in 51centers on radiology staff, radiography room and protective barrier, ray leakage, the outcome were 89%, 82%, 77% and 37% respectively. It was found that the condition of these centers regarding the protective barriers is very unsuitable due to unawareness of the leakage (5, 6).Considering the mentioned necessities, in this study, the condition of radiography centers affiliated to the Mazandaran University of Medical Sciences was studied for the type and the rate of problem, in order to provide a proper solving method. Results Data were collected through, observation, interviewing and filling questionnaire. Results show that, the situations of the radiology units are for from international standard, to such an extent that it is matched clout 50%. Conclusion The results showed that, none of the dark rooms are standard, and do not have proper alarm signal. In 63% of these units there no tiling system about staff protection from radiation. Defects in radiography room, protective barrier and lack looking rays were 60%, 51% and 47% respectively. Referring to the obtained data, periodic supervision, and obeying of the standards are necessary.

Generative Aspects of Oxide Pictures by Oxide Tile Rewriting Grammar

In formal languages, picture language is generalization of string language theory to two dimensions. Pictures which may be regarded as two-dimensional objects occur in studies concerning recognition of patterns, images and various computational fields. Several studies have been done for generating and/or recognizing higher dimensional objects using formal models. Tile rewriting grammar (TRG) is yet another model introduced for generating picture languages. TRG combines isometric rewriting rules with the Giammaresi and Restivo’s Tiling system. This rewriting grammar generates spirals, square and rectangular grids. The power of generating pictures by tile rewriting grammar is more than REC .Sweety et al have generated hexagonal pictures, introducing hexagonal Tile Rewriting Grammar. Kuberalet al have introduced Triangular Tile Rewriting Grammar to generate Triangular Pictures. A special class of objects namely Oxide pictures have been of interest recently. Oxide network is a special case of Silicate network. The silicates are a complicated class of minerals made up of tetrahedral silicates. A basic silicate tetrahedron unit SiO4 is formed with Oxygen ions in the corners and a Silicate ion in the center. In a two dimensional plane a ring of tetrahedrons that are shared by Oxygen nodes forms a silicate sheet.In this paper, Oxide Tile Rewriting Grammar (OXTRG) is proposed for generating Oxide pictures. The motivation for the study is derived from the Oxide network which is obtained by deleting all the silicon nodes of a silicate network. Closure properties of OXTRG are discussed. When compared with schemes such as Oxide Tiling System and Oxide Sgraffito Automaton, OXTRG is found to be more powerful.

Computation and Clay: Evolving Fabrication and Performance Strategies for Ceramics in Architecture

Throughout civilization, fired clay has taken on various roles, ranging from utilitarian objects to decorative art. In architecture, fired clay, as a building material, demonstrates a wide range of uses. Typically used as a tiling system, ceramics have provided a means of waterproofing buildings, protecting structures from fires, and as an aesthetic device for decorating surfaces.

A stronger recognizability condition for two-dimensional languages

Automata, Logic and Semantics International audience The paper presents a condition necessarily satisfied by (tiling system) recognizable two-dimensional languages. The new recognizability condition is compared with all the other ones known in the literature (namely three conditions), once they are put in a uniform setting: they are stated as bounds on the growth of some complexity functions defined for two-dimensional languages. The gaps between such functions are analyzed and examples are shown that asymptotically separate them. Finally the new recognizability condition results to be the strongest one, while the remaining ones are its particular cases. The problem of deciding whether a two-dimensional language is recognizable is here related to the one of estimating the minimal size of finite automata recognizing a sequence of (one-dimensional) string languages.

Boiler Wall Protection With Rear Ventilated Refractory Tiles

The prevention of corrosion on boiler tube-walls has been a most difficult and cost intensive problem in WTE plants. This is specifically the case where the incineration boilers are operating with increased saturated steam temperatures and their corresponding pressures. In addition, variations in the garbage mixtures, with differing values of chemical content and varying waste composition give importance to the prevention of boiler tube corrosion. Several refractory lining systems and types have been installed over the previous 80 years and can be compared. In the early stages it began with simple concrete installations and only later was it developed to use heat resistant ceramic products, now essentially silicon carbide. 20 years ago cement or chemically bonded SiC monolithics (gunning, trowelling or casting materials) were usually installed to protect boiler walls, but today fabricated and fired SiC tiles, with their enhanced properties, are mainly used. A distinction is made between hanging and bolted tiles, as well as between oxide bonded and nitride bonded SiC material and between mortared, backfilled and rear ventilated tiles. All these systems were carefully examined and assessed. It proved possible to develop a revolutionary heat conduction and corrosion protection system utilising air. An air gap between the refractory SiC tiles and the boiler wall proved to be both simple and successful. By means of detailed and systematic documentation and monitoring, including J + G’ s “Air” tiling system, it has, for a few years, been possible to offer and recommend long lasting refractory linings with the aim of protecting boiler walls against corrosion, reducing operating costs and using the energy of the waste in an optimum manner.