Imagine a large building with many corridors. A robot cleans these corridors in a greedy fashion, the next corridor cleaned is always the dirtiest to which it is incident. We determine bounds on the minimum s(G) and maximum S(G) number of time steps (over all edge weightings) before every edge of a graph G has been cleaned. We show that Eulerian graphs have a self-stabilizing property that hold...

Perfect vertex elimination schemes are part of the characterizations for several classes of graphs, including chordal and cop-win. Partial elimination schemes reduce a graph to an important subgraph, for example, k-cores and robber-win graphs. We are interested in those partial elimination schemes, in which once a vertex can be eliminated it is always ready to be eliminated. In such a scheme, t...

Superhydrophobic surfaces have great potential for self-cleaning, anti-icing, and drag-reducing characteristics because of their water repellent property. This study demonstrates the application coatings to protect architectures from detrimental atmospheric effects via a self-cleaning approach. In this research, SiO2-TiO2-PDMS composite coating was prepared on surface building walls by sol-gel ...

Methods: In this study, cleaning process was studied and analyzed with special reference to cleaning tools. A group of 13 professional cleaners participated in this study. While they performed their normal tasks, their oxygen consumption, heart rate, rating of perceived exertion and postural data were obtained. The perceived exertion during cleaning task using the ‘‘redesigned cleaning tool’’ w...

the objective of this study was to evaluate the presence of perchloroethylene (pce) and trichloroethylene (tce) in dry cleaning shops in tehran, iran. pce and tce are two most prevalent solvents in dry-leaning shops. air and effluent samples were collected in october to december 2011 from 10 dry-cleaning shops. analyses were performed by head-space gas chromatography technique. gas chromatograp...

Inadequate hole cleaning can lead to many problems in horizontal and directional wells. In this work, we tried to investigate the cutting transport phenomenon by an experimental directional drilling simulator, considering the differences between the operational and experimental conditions. The inclination, fluid type (water, foam, viscous, and dense), rotary speed (0 and 110 rpm), nozzle bit si...

In this study, thermodynamic and economic analysis of a photovoltaic electricity generation system (PVEGS) with and without self-cleaning panels is reported. In the first part, thermodynamic analyses are used to characterize the performance of the system. In the second part, the economic comparison of photovoltaic electricity generation with and without self-cleaning panels is carried out for a...

OBJECTIVE Studies have demonstrated frequent contamination of stethoscope and usefulness of different disinfectants. Albeit, studies on the precise mode of cleaning and frequency of cleaning are lacking. This study was carried out to determine efficacy of 66% ethyl alcohol as disinfectant, rate of recontamination without cleaning and benefits of daily versus immediate cleaning. METHODOLOGY Pr...