Self-cleaning mechanisms

The self-cleaning mechanisms of photocatalysis and photosensitization apply also to organic matter included in microorganisms, so it can also lead to selfdisinfection. This is especially expected near a semiconductor (particularly T1O2) and/or iron deposits, which are responsible for solar photogeneration of reactive oxygen species capable of water disinfection [78,79,100,101]. 

It has been found that the basal cells replicate continuously to provide a self-cleaning mechanism to the epithelial layer. Autoradiographic studies of cell proliferation were performed on normal human cervix and vagina. The turnover time, an indication of the time required for the replacement of the cell population, was determined from these studies. Results showed the basal layer to be relatively inactive with a turnover rate of 33 days, while active proliferation occurred in the parabasal layers with a turnover rate of 3 days. The intermediate and superficial layers were found to be inactive differentiating compartments. 

Emissions from biomass burning could disrupt the oxidizing potential of the atmosphere. The atmosphere has a self-cleaning mechanism, which photochemically oxidized pollutants, such as hydrocarbons, to carbon dioxide, preventing their buildup... 

Unlike the human body, equipment does not have a self-cleaning mechanism. Equipment and surfaces may still be contaminated with anthrax spores for a period of time after an exposure has occurred. For this reason, it still makes sense to swab tables long after it no longer makes sense to swab noses. 

Computational Analysis of Wetting on Hydrophobic Surfaces Application to Self-Cleaning Mechanisms... 

Keywords Self-cleaning mechanism, contact angle, static wetting, nonlinear finite element analysis, droplet membranes. 

We consider the system model depicted in Figure 5.2, which describes the self-cleaning mechanism through the following sub-models (1) droplet model, (2) substrate surface model, and (3) particle-droplet interaction model. Since quasi-static conditions are considered in this work, it is convenient to treat the droplet as a hydrostatic bulk and a deformable liquid membrane. The latter is modeled using the stabilized FE formulation introduced by Sauer [15], which captures the in-plane equilibrium of the membranes due to constant surface tension. The multi-scale nature of self-cleaning surfaces can be mathematically modeled as 2D sinusoidal functions as done by Bittoun and Marmur [19], and Iliev and Pesheva [20],... 

In addition, composite systems can be manufactured with smart materials to identify damage and lead to self-healing or even self-cleaning mechanisms [8]. Composite applicahons are not limited to new structures, as they can be utilized to rehabilitate or upgrade existing structures for safety or to increase load-carrying capacity. A few of these aspects are briefly described in the sections given later. 

The global increase of tropospheric O3, CO, and CH4 concentrations, which is expected to continue in the future, is an indication of a fundamental change in the chemical behavior of the troposphere. Many gases, particularly hydrocarbons, are continuously emitted into the atmosphere from natural and anthropogenic sources. A buildup of these gases in the atmosphere is prevented by a self-cleaning mechanism, whereby these substances are slowly combusted photochemicaUy to COz-... 

---