Effects Of Surface Porosity Research Articles

Effect of Surface Porosity on SARS-CoV-2 Fomite Infectivity.

Previous reports indicated the low stability of severe actute respiratory syndrome coronovirus 2 (SARS-CoV-2) on various porous surfaces, but the role of porosity was unclear because there was no direct comparison between porous and nonporous solids of the same chemistry. Through comparing pairs of solids with very similar chemistry, we find that porosity is important: porous glass has a much lower infectivity than nonporous glass. However, porosity is not sufficient to lower infectivity; permeability, which is the ability of a liquid to move through a material, is the important parameter. We show this by comparing a pair of porous CuO coatings where the pores are accessible in one case and inaccessible in the other case. When the pores are inaccessible, the infectivity remains similar to that for nonporous solids. Thus, for both glass and CuO, it is the access to porosity that decreases the infectivity of extracted liquid droplets. Having established the importance of permeability, there is the open question of the mechanism of changing the infectivity of SARS-CoV-2. Several hypotheses are possible, such as increasing the difficulty of extracting the virus from the solid, changing the drying time, increasing the surface area of active ingredient, etc. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) measurements show that less viral DNA is extracted from a permeable surface, suggesting that the virus becomes trapped in the pores. Finally, we consider the effect of drying. We show that permeability and the water contact angle on the solid have effects on the drying time of a contaminated droplet, which may in turn affect infectivity.

Effect of surface porosity on ceramics during Al2O3/Ti bonding through brazing

Effect of surface porosity on ceramics during Al2O3/Ti bonding through brazing

Effects of Surface Porosity and Wettability Patterning on Saturated Boiling of Ethanol

Effects of Surface Porosity and Wettability Patterning on Saturated Boiling of Ethanol

Effect of Surface Porosity on Tribological Properties of Sintered Pure Al and Al 6061

Due to light weight, high specific strength, high corrosion resistance and good heat transfer ability, aluminium alloys are becoming attractive for critical structural applications. These alloys can be manufactured using powder metallurgy techniques in which porosity is a common characteristic. The presence of pores is responsible for decreasing effective load bearing cross sectional area and inducing stress concentration sites for strain localization and damage, decreasing both strength and ductility. The present study aims to establish a better understanding of the relationship between surface porosity and corresponding wear behavior. In this study, porous specimens were produced using powder metallurgy technique and the extent of wear damage and the type of wear was investigated under low load range of 1.5 - 5 N against AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration and frequency of 10 Hz. Scanning electron microscopy of the wear tracks and wear debris was carried out to understand wear mechanisms. This study revealed that due to combined effect of high stress intensity and subsurface cracking, wear rate increases with increasing porosity content. The friction and wear behavior of pure Al and Al 6061 as a function of porosity content can be attributed to their hardness and corresponding wear mechanism.

Effect of surface porosity on osteoclast resorption ability

Effect of surface porosity on osteoclast resorption ability

Effects of surface porosity on the fatigue strength of AE425 and PM390 hypereutectic Al–Si casting alloys at medium and elevated temperatures

The effects of surface porosity on the fatigue life of AE425 and PM390 hypereutectic Al–Si casting alloys were investigated at medium and elevated temperatures (150 °C and 300 °C, respectively) for the purposes of the present study. Surface porosity was found to be the most critical casting defect which influenced the fatigue life of hypereutectic alloys at medium and elevated temperatures. The most frequently observed site for fatigue crack initiation was surface porosity, where 89% of all samples tested tended to fracture because of this particular defect. Thus, surface porosity was shown to have a detrimental effect on the fatigue performance of the alloys in question. It was observed that the fatigue strength decreases as the surface pore size increases, and vice versa. The SEM technique used to identify fatigue crack initiation sites, or surface porosity, may be applied with a high degree of accuracy for measuring single pores responsible for triggering such cracks. When the crack initiation area contains multiple pores or consists of a spongy structure (as in the case of AE425 alloy), the technique used is not in itself sufficient to determine the exact site, and it should, therefore, be re-evaluated to provide greater accuracy of results. It was also observed that, the decohesion and damage of silicon particles in hypereutectic alloys under cyclic loading weakens the overall structure and accelerates the occurrence of fatigue fractures.

Effects of surface porosity on tungsten trioxide(WO3) films’ electrochromic performance

In this paper, the correlation between the electrochromic performance and the surface morphology of the tungsten trioxide (WO3) thin films sputtered by dc reactive magnetron sputtering with widely varying target-substrate distances was investigated. It is found that the optical density change (ΔOD) of films is strongly affected by the target-substrate distance. The coloration efficiency (CE) at 633 nm was also found to be sensitive to the target-substrate distance, with 16 cm2/C of film sputtered at 6 cm and 50 cm2/C at 18 cm. X-ray diffraction showed that the crystal structure of films was amorphous. By using atomic force microscope to identify the surface porosity of the sputtered WO3 films, we found that the film at longer target-substrate distance was rough, porous, and having a cone-shaped columns morphology, thus offering a good electrochromic performance for opto-switching applications.

Pore structure of superporous hydrogels

Hydrogels with a fast swelling property have been synthesized using a gas blowing technique. Since those hydrogels possess interconnected pores of which diameters are in the order of a few hundred micrometers, they are called “superporous hydrogels” (SPHs). The fast swelling of SPHs in aqueous solution is due to the absorption of water by capillary pressure through interconnected pores (i.e. open channels). Because of the importance of pore structures on the fast swelling property, effects of surface porosity on the swelling kinetics were examined. The surface chemistry of the polymerization mold made of glass was varied using various silanes, and the surface morphology of the synthesized SPHs was examined by scanning electron microscopy. The porosity was measured using mercury porosimetry. Despite differences in surface morphology and surface porosity of SPHs, the swelling kinetics were not changed significantly. The internal pore structures remained the same as the surface porosity changed. The study indicates that the swelling of SPHs is predominantly determined by the internal pore structures, and small differences in the surface porosity do not alter the overall swelling kinetics of SPHs. Copyright © 2000 John Wiley & Sons, Ltd.

Effect of Surface Porosity on Emittance of an Opaque Substance

Effect of Surface Porosity on Emittance of an Opaque Substance