The characteristics of arbitrary amplitude DUST ion acoustic solitary waves (DIASWs) are studied in unmagnetized DUSTy plasmas whose constituents are cold uid ions, nonextensive electrons and stationary negative/positive DUST particles. The pseudopotential approach has been used to investigate the structure of localized waves. It is found that, solitary waves exist in a definite interval for the Mach number which depends sensitively to the electron nonextensivity and DUST polarity. Our results can be useful to understand the properties of localized electrostatic disturbances that may occur in astrophysical and space DUSTy plasmas.

As surfactants enhance the membrane transport of organic compounds, it has to be assumed that they decisively influence the absorption of pollutants from house DUST. Sampling sites for the surfactant analysis include housing areas, each location of which has different surroundings such as rural, urban, construction, and inDUSTrial area. Three stations had been selected for each housing area and cooking and smoking activities were recorded for each house. The concentration of anionic and cationic surfactants was determined as Methylene Blue Active Substances (MBAS) and Disulphine Blue Active Substances (DBAS) methods each using an ultraviolet-visible spectrophotometer. The results indicated that the concentrations of MBAS and DBAS in indoor DUST were much higher than the street DUST. It is concluded that activities in the house itself contributed significantly to the high concentration level of MBAS and DBAS in indoor DUST. Overall, the sequence of concentration level of anions is as follows, Cl- > NO3- > SO42-. The correlation between MBAS with all the anions are weak (R2 chloride=0.0072, R2 nitrate=0.2469, R2sulphate=0.00004) signifying that there is only a little connection between surfactants and these anions.

The results showed that DUST occurrence has an increasing trend in Sabzevar within the study period with a higher likelihood during May and June. Also more than 71 percent of the DUSTstorms occurred during the afternoon. Dominant wind within the annual Wind Rose and DUST Rose is from east. Annually 85.4 percent of overall wind flow and 81.36 percent of DUST-flow blow in east-west direction. Hence it seems that a new canal is created at this direction. This finding is in harmony with topographical conditions of the area. Annual "DUST Rose" showed that average speed for DUST Winds is 8.75m/s and about 50 percent of them have speed of over 9m/s. The study of monthly DUST Rose indicated the influence of different atmospheric systems over the formation of DUST events in Sabzevar. From May to September, duration of sun shine increases and extensive plains and playas within the area has led to the predominance of thermal systems with prevailing "DUST Wind" direction from east. From October to May, eastern DUST Wind is decreasing but western and south western DUST Winds increasing due to the predominant of the western systems. For example, prevailing wind direction according to the Wind Rose in February is from east but dominant DUST Wind direction at the same period is completely from west. Comparison of the monthly "Resultant Vector" over the year supports such a behavior. This study can be useful for controlling of the DUST sources and to help the regional planning towards a sustainable development.

More than two thirds of the total area in Iran has been covered by arid and semi-arid regions and climate. Although DUST storm is an important environmental issue in these regions, especially in western and southwestern provinces, limited information is available regarding characteristics and sources of such phenomena. This study was carried out to identify deposition rate, particle size distribution, heavy metal (Zn, Pb, and Cd) concentrations, and mineralogical composition of DUST particles collected using marble DUST collector (MDCO) from 15 sampling points in Ahvaz city during a 6 month period in 2011. Results indicated that the average level of deposited particles within the DUST storm periods was considerably more pronounced than that of the period’s with no DUST storms. The results illustrated that, due to such local factors as the presence of bare lands surrounding the city, and abandoned constructional projects, DUST deposition rate in such areas was far more than in other localities. Results also indicated the mineralogical composition of the DUST particles mainly comprised of calcite, quartz, and feldspars. Results of particle size distribution analysis showed that the DUST particles were mainly silt-sized. However, with occurrence of DUST storms, the size of particles became tinier. The highest concentrations of the heavy metals Pb, Cd and Zn were observed downtown and in the inDUSTrial neighborhood of the city. In addition, the greatest concentration of the heavy metals was observed in December as compared with the other months of the study period.

In drylands, both DUST storms and ephemeral salt lakes (playas) are common. Observations using remote sensing and ground studies have shown that these playas can be major sources of saline DUST storms. Some basins have recently become desiccated as a result of water abstraction by humans, and these have become significant sources of DUST. The timing and amounts of DUST emissions depends on such factors as rainfall and drought events, the availability of sediment, and the nature of surface crust materials.

Background and Aim: Evaluation of the performance of these products is mainly based on their efficiency in numerical removal of particles in the range of different sizes. While the most important features of filters are the DUST holding capacity, and the ability to remove the mass of particles with different densities, fewer studies have addressed this issue. Therefore, the present study evaluates the DUST holding capacity of nanofiber media and its ability to capture synthetic DUST to determine its ability to remove the mass of particles with different densities. At the same time, the initial efficiency of the fabricated media in the numerical removal of particles is also examined. Methods: For producing nanofibers, a 16% w/w electrospinning solution of polyacrylonitrile polymer was prepared. The initial efficiency test in numerical removal of particles was performed according to ISO 29463 standard and the BS EN 779 standard was used for synthetic DUST capture or arrestance test. Morphological characteristics, diameter, and surface porosity of the produced nanofibers were investigated using scanning electron microscopy. Results: The investigation of the numerical removal of particles by the produced media showed that the average initial efficiency for collecting particles from 10 to 1000 nm was 72. 06 ±,19. 62%. The results of the arrestance test showed that with increasing the mass of injected particles in different loading stages, the media pressure drop also increases. The DUST holding capacity and the arrestance of the media for the final pressure drop of 265 Pascal were calculated to be about 180 mg and 99. 86%, respectively. The total mean of arrestance was calculated to be about 99. 86% after 6 loading steps. The morphological characterization of the produced nanofibers showed that the average diameter of the fibers was 380 nm with a coefficient of variation of 1. 20, the morphology of nanofibers was non-uniform, and the surface porosity was determined to be 51%. Conclusion: Proper collection efficiency and DUST holding capacity, along with the low thickness of nanofiber media, make their applicability more specific in air filtration properties.