scholarly journals Windblown Sand-Induced Degradation of Glass Panels in Curtain Walls

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 607
Author(s):  
Yuxi Zhao ◽  
Rongcheng Liu ◽  
Fan Yan ◽  
Dawei Zhang ◽  
Junjin Liu

The windblown sand-induced degradation of glass panels influences the serviceability and safety of these panels. In this study, the degradation of glass panels subject to windblown sand with different impact velocities and impact angles was studied based on a sandblasting test simulating a sandstorm. After the glass panels were degraded by windblown sand, the surface morphology of the damaged glass panels was observed using scanning electron microscopy, and three damage modes were found: a cutting mode, smash mode, and plastic deformation mode. The mass loss, visible light transmittance, and effective area ratio values of the glass samples were then measured to evaluate the effects of the windblown sand on the panels. The results indicate that, at high abrasive feed rates, the relative mass loss of the glass samples decreases initially and then remains steady with increases in impact time, whereas it increases first and then decreases with an increase in impact angle such as that for ductile materials. Both visible light transmittance and effective area ratio decrease with increases in the impact time and velocities. There exists a positive linear relationship between the visible light transmittance and effective area ratio.

2018 ◽  
Vol 14 (S343) ◽  
pp. 466-467
Author(s):  
M. Mečina ◽  
B. Aringer ◽  
M. Brunner ◽  
F. Kerschbaum ◽  
M. A. T. Groenewegen ◽  
...  

AbstractHerschel PACS imaging observations of carbon stars show well-resolved spherically symmetric detached shells around several objects. In the case of U Hya the shell is additionally detected in scattered visible light and in the far UV. The remarkable spherical symmetry justifies a straightforward application of 1D models to constrain the properties of the dust envelope, whose modulation in density is a consequence of short epochs of highly increased mass loss and/or wind-wind interaction between outflows of different velocity. We perform dust radiative transfer calculations, first based on a parametrised density distribution, and in a more sophisticated approach on a combination of stationary wind models. The impact of dust properties, particularly grain geometry, on the results is highlighted.


Holzforschung ◽  
2005 ◽  
Vol 59 (5) ◽  
pp. 568-573 ◽  
Author(s):  
Morten Eikenes ◽  
Ari M. Hietala ◽  
Gry Alfredsen ◽  
Carl Gunnar Fossdal ◽  
Halvor Solheim

AbstractThis paper describes the use of quantitative real-time PCR for monitoring colonization of birch wood (Betula pubescens) by the white-rot fungusTrametes versicolorin an EN113 decay experiment. The wood samples were harvested after 4, 8, 12, 16 and 20 weeks of incubation. The mass loss was in the range of 4–40%. Chitin and ergosterol assays were conducted for comparison. Second-order polynomial fits of the mass loss of decayed wood versus chitin, ergosterol and DNA gave correlations (r2) of 0.87, 0.61 and 0.84, respectively. Compared to the other two assays employed, real-time PCR data correlated best with the relative mass loss of decayed samples 4–8 weeks after inoculation, while the saturation and decline of DNA-based estimates for fungal colonization 16–20 weeks after inoculation indicated that the DNA assay is not suited for quantification purposes in the late stages of decay. The impact of conversion factors, extraction efficiency, inhibitory compounds and background levels in relation to the three detection assays used is discussed.


1978 ◽  
Vol 79 ◽  
pp. 121-122 ◽  
Author(s):  
Peter Biermann ◽  
Roland Wielen

We have studied hyperbolic encounters of spherical galaxies by self-consistent N-body simulations. Each galaxy is represented by a Plummer model. A galaxy contains up to 250 “particles”. the force between the particles is properly softened in order to avoid an unrealistic internal evolution due to close encounters of the particles. the results of these numerical experiments, carried out by R.W., are compared with theoretical predictions based on the impulsive approximation, made by P.B. in order to facilitate the assessment of such a comparison, the passing galaxy is here represented by a rigid gravitational field, moving on a straight line. in the table given below, we compare the relative mass loss, ΔM/M, and the relative change in the total internal energy of a galaxy, ΔE/E, for two cases. Both galaxies are of equal mass and size; the impact parameter is equal to the median radius of a galaxy (containing 50% of its mass in projection); the initial relative velocity would correspond to the orbital excentricity e as given, if the galaxies were mass points. While the agreement is fair with respect to the energy transfer ΔE, the theory predicts a mass loss of more than 10% (or 25 particles) in cases where no mass loss is observed in the N-body simulations the probable reason for this discrepancy is the failure of the impulsive approximation in these cases. A mass loss of the order of 1% or less cannot be ruled out in the N-body calculations, because of the limited number of particles. the significant increase of the internal energy of a galaxy during an encounter leads to an expansion of the outer parts of the galaxy. This expansion may finally lead to a mass loss as soon as the outer parts have expanded beyond the tidal radius of the galaxy caused by its cluster environment. the inelasticity of galactic encounters has implications for the dynamical evolution of groups and clusters of galaxies. the groups and clusters will shrink in radius because of the loss of orbital energy which is used to expand the individual galaxies. the final amount of collapse of the group or cluster is governed by the relative amount of the internal binding energies stored initially in the individual galaxies and released during the galactic encounters, in comparison to the binding energy of the group or cluster.


Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 545
Author(s):  
Grzegorz P. Łysiak ◽  
Krzysztof Rutkowski ◽  
Dorota Walkowiak-Tomczak

Late pear cultivars, such as ‘Conference’, can be stored for a long period if kept in good storage conditions. A three-year study (2011–2013) compared the impact of six-month storage using four technologies—normal atmosphere, normal atmosphere + 1-methylcyclopropene (1-MCP), controlled atmosphere, and controlled atmosphere + 1-MCP—on the quality parameters of ‘Conference’ pears, such as mass loss, firmness, total soluble solids, acidity, antioxidant capacity, and the incidence of diseases and disorders. Additionally, the study analysed different storage conditions in terms of profitability, based on the market prices for pears in the seasons during which the pears were stored. The storage conditions had a very strong influence on the fruit quality parameters, and were found to affect most visibly the mass loss and the incidence of postharvest diseases and disorders. The storage of ‘Conference’ pears for 180 days in normal atmosphere is not economically viable, even if the fruit is subjected to 1-MCP treatment; at the same time, it is profitable to store ‘Conference’ pears in controlled atmosphere for the same period, no matter whether 1-MCP was applied or not.


Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 81
Author(s):  
Francesca Tessore ◽  
Federico Galli ◽  
Dalma Schieppati ◽  
Daria C. Boffito ◽  
Alessandro Di Michele ◽  
...  

Photocatalysis is a green technology for tackling water and air contamination. A valid alternative to the most exploited photocatalytic material, TiO2, is bismuth oxyhalides, which feature a wider bandgap energy range and use visible radiation to attain photoexcitation. Moreover, their layered structure favors the separation of photogenerated electron–hole pairs, with an enhancement in photocatalytic activity. Controlled doping of bismuth oxyhalides with metallic bismuth nanoparticles allows for further boosting of the performance of the material. In the present work, we synthesized Y%Bi-doped BiO(Cl0.875Br0.125) (Y = 0.85, 1, 2, 10) photocatalysts, using cetyltrimethylammonium bromide as the bromide source and varying the chloride source to assess the impact that both length and branching of the hydrocarbon chain might have on the framing and layering of the material. A change in the amount of the reducing agent NaBH4 allowed tuning of the percentage of metallic bismuth. After a thorough characterization (XRPD, SEM, TEM, UV-DRS, XPS), the photocatalytic activity of the catalysts was tested in the degradation of NOx under visible light, reaching a remarkable 53% conversion after 3 h of illumination for the material prepared using cetylpyridinium chloride.


Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2064
Author(s):  
Jin-Hee Kim ◽  
Seong-Koo Son ◽  
Gyeong-Seok Choi ◽  
Young-Tag Kim ◽  
Sung-Bum Kim ◽  
...  

Recently, there have been significant concerns regarding excessive energy use in office buildings with a large window-to-wall ratio (WWR) because of the curtain wall structure. However, prior research has confirmed that the impact of the window area on energy consumption varies depending on building size. A newly proposed window-to-floor ratio (WFR) correlates better with energy consumption in the building. In this paper, we derived the correlation by analyzing a simulation using EnergyPlus, and the results are as follows. In the case of small buildings, the results of this study showed that the WWR and energy requirement increase proportionally, and the smaller the size is, the higher the energy sensitivity will be. However, results also confirmed that this correlation was not established for buildings approximately 3600 m2 or larger. Nevertheless, from analyzing the correlation between the WFR and the energy requirements, it could be deduced that energy required increased proportionally when the WFR was 0.1 or higher. On the other hand, the correlation between WWR, U-value, solar heat gain coefficient (SHGC), and material property values of windows had little effect on energy when the WWR was 20%, and the highest effect was seen at a WWR of 100%. Further, with an SHGC below 0.3, the energy requirement decreased with an increasing WWR, regardless of U-value. In addition, we confirmed the need for in-depth research on the impact of the windows’ U-value, SHGC, and WWR, and this will be verified through future studies. In future studies on window performance, U-value, SHGC, visible light transmittance (VLT), wall U-value as sensitivity variables, and correlation between WFR and building size will be examined.


2021 ◽  
pp. 095745652110015
Author(s):  
Zhijian Xu ◽  
Guoming Zhang ◽  
Xiaoyu Ji ◽  
Wenyuan Xu

The in-car voice controllable system has become an almost standard feature in smart cars. Prior work shows that the voice controllable system is vulnerable to light commands attack which uses the laser as the medium to inject voice commands. In this article, we first reproduced the light commands attack on acoustic isolated in-car voice controllable system under several scenarios with a lightweight solution. We validate the feasibility of injecting the malicious voice command through a window into the microphone by modulating a laser beam. Then, we tested a variety of mainstream countermeasures such as placing sunscreen film on the glass panel to see whether it can protect the microphone from being attacked. Surprisingly, we find that the lower light transmittance of sunscreen film is the lower the success rate of the attack. Experiment results also show that when the transmittance rate of sun film is 50% which is the darkest sunscreen film that can be applied, the attacking success rate decreased by up to 0.4. We also explore the impact of attack angle by changing the incidence angle of the laser beam and the results demonstrate that light commands is sensitive to attack angle and the successful angle range is ± 15°. Finally, we propose a series of hardware-based protection schemes against light commands attacks.


2018 ◽  
Vol 53 ◽  
pp. 01013
Author(s):  
Nan Zhang ◽  
Mengyuan Xu ◽  
Ning Li

The existing building energy-saving reconstruction has a large area in our country. If the performance indexes such as the shading coefficient, visible light transmittance and hardness of the coating heat-insulating glass are in the condition of reaching the specification, and it can meet the needs of energy conservation and reform in building, it is a suitable technology for economic application.


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