Experimental Study on the Shear Adhesion Strength Between the Ice and Substrate in Icing Wind Tunnel

2017 ◽  
Vol 34 (2) ◽  
pp. 209-216 ◽  
Author(s):  
C. X. Zhu ◽  
C. L. Zhu ◽  
W. W. Zhao ◽  
M. J. Tao

AbstractThe icing wind tunnel can simulate the air flow at a high altitude; such an air flow contains supercooled droplets moving at certain velocities. An integrated experiment method was proposed, and it included the icing test and shear stress measurements in the simulated environment of the icing wind tunnel. The error caused by the change in experimental environments was completely eliminated with this novel method. Thus, there was no discrepancy between the real-time and experimental values of shear stress between the ice and substrate. The experiments of icing and shear stress measurements are carried out by varying the following parameters: icing temperature, mean volume diameter (MVD) of droplets, and surface roughness of the substrate. The results indicate that the shear stress between the ice and the substrate increases with the decrease in temperature provided the temperature is relatively high. When the MVD value is 22 μm, the liquid water content is about 1 g/m3and surface roughness is 2 μm. Under these conditions, the shear stress reaches its maximum value at a temperature of –15°C. The shear stress is also affected by the MVD values of droplets, and the surface roughness of substrate.

2009 ◽  
Vol 8 (5) ◽  
pp. 631-640 ◽  
Author(s):  
Winnie W. Y. Chow ◽  
Yanli Qu ◽  
Wen J. Li ◽  
Steve C. H. Tung

Author(s):  
Brett Freidkes ◽  
David A. Mills ◽  
Casey Keane ◽  
Lawrence S. Ukeiley ◽  
Mark Sheplak

2020 ◽  
Vol 32 (12) ◽  
pp. 125120
Author(s):  
María Jiménez-Portaz ◽  
Luca Chiapponi ◽  
María Clavero ◽  
Miguel A. Losada

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 549 ◽  
Author(s):  
Bruna Sinjari ◽  
Gianmaria D’Addazio ◽  
Martina Bozzi ◽  
Manlio Santilli ◽  
Tonino Traini ◽  
...  

The aim of this in vitro study was to evaluate the enamel surface topography after treatment with three air polishing powders: Glycine (A), erythritol (B), and sodium bicarbonate (C) (Air Flow Soft, Plus and Classic powders, EMS Electro Medical Systems S.A., Nyon, Switzerland). Fifteen extracted incisors were randomly divided into three groups of five teeth each, A, B and C, respectively. The teeth were blocked in plaster bases, washed, dried and half-covered with polytetrafluoroethylene strips before treatment. In this way, each half-treated dental element became test and control of itself. Comparative statistical analysis of Rq (geometric average of the deviations occurring in roughness profile) was performed. The scanning electron microscope (SEM) analysis showed different degrees of surface roughness between the groups, decreasing after treatment. In addition, a statistically significant reduction p < 0.05 was present in group C (Rq mean non-treated 108.17 µm, 95% CI: 97.29–124.01 and Rq mean treated 86.78 µm, 95% CI: 80.63–93.70). A decrease in surface roughness post-treatment was not observed in group A and B. Therefore, it may be concluded that the air flow powders tested herein can be used on dental enamel to reduce the surface roughness due to function and the action of dental therapies.


2002 ◽  
Vol 749 ◽  
Author(s):  
Vincent Barrioz ◽  
Stuart J. C. Irvine ◽  
D. Paul

ABSTRACTZnS is a material of choice in the optical coating industry for its optical properties and broad transparency range. One of the drawbacks of ZnS is that it develops high compressive intrinsic stress resulting in large residual stress in the deposited layer. This paper concentrates on the evolution of residual stress reduction in ZnS single layers, depending upon their deposition rate or the substrate temperature during deposition (i.e. 22 °C and 133 °C). The substrate preparation is addressed for consideration of layer adhesion. Residual stress of up to − 550 MPa has been observed in amorphous/poor polycrystalline ZnS layers, deposited on CMX and Float glass type substrates, by electron beam evaporation at 22 °C, with a surface roughness between 0.4 and 0.8 nm. At 133 °C, the layer had a surface roughness of 1 nm, the residual stress in the layer decreased to − 150 MPa, developing a wurtzite structure with a (002) preferred orientation. In situ stress measurements, using a novel optical approach with a laser-fibre system, were carried out to identify the various sources of stress. A description of this novel in situ stress monitor and its advantages are outlined. The residual stress values were supported by two ex situ stress techniques. The surface morphology analysis of the ZnS layers was carried out using an atomic force microscope (AFM), and showed that stress reduced layers actually gave rougher surfaces.


1997 ◽  
Vol 63 (615) ◽  
pp. 3557-3563
Author(s):  
Yoshihiro NAGAOKA ◽  
Grant ALEXANDER Hani ◽  
HO Chih-Ming ◽  
LIU Wayne

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