The white marble domes of the Taj Mahal are iconic images of India that attract millions of visitors every year. Over the past several decades the outer marble surfaces of the Taj Mahal have begun to discolor with time and must be painstakingly cleaned every several years. Although it has been generally believed that the discoloration is in some way linked with poor air quality in the Agra regi...

This paper compares the use of ultraviolet germicidal irradiaiton (UVGI) with increased ventilation flow rate to minimize the risk from airborne bacteria in hospital isolation rooms. Results show that the number of particles deposited on surfaces and vented out is greater in magnitude than the number killed by UV light and that the numbers for these two mechanisms are large compared to the tota...

Road dust is composed by natural and anthropogenic particles, to be collected on surface and along roadsides. This material contributes significantly to atmospheric particulate matter by resuspension of finer particles [1]. In urban, suburban or industrial centers, it may even represents the dominant source of PM10 (particles with aerodynamic diameter less than 10 m). The objectives of this wor...

A new measurement technique was studied using catalysis to specifically detect airborne nanoparticles in presence of background particles in the workplace air. Catalytically active nanoparticles produced by spark discharge were used as aerosol catalysts. According to these particles suitable catalytic test reactions were chosen and investigated by two different approaches: catalysis on airborne...

We consider the Takaysu model with desorption. Particles are deposited on the hypercubic lattice Zd. At each site individual particles arrive at rate q. The top-most particle at each non-empty site evaporates at rate p. The particles also diffuse in the manner of coalescing random walks: at rate one, the stack of particles sitting at a site is moved to a randomly chosen neighbor, joining any pa...

AISI 4140 powder was directly deposited on AISI 4140 wrought substrate using laser engineered net shaping (LENS) to investigate the compatibility of a LENS-deposited part with the substrate. Tensile testing at room temperature was performed to evaluate the interface bond performance and fracture behavior of the test specimens. All the samples failed within the as-deposited zone, indicating that...

Carbon particles extracted from sediments collected by box coring from southeastern Lake Michigan were compared with carbon particles extracted from oil, coal, and wood fly ash. Sediments deposited after 1900 contained coal, oil, and wood carbons; older sediments contained only wood carbon.

Here, we report a seeded growth protocol for synthesizing monodisperse Si-DDR particles of ~1.3-10 μm by varying the seed amount. These Si-DDR particles were deposited onto porous α-Al2O3 discs via sonication-induced assembly, constituting close-packed h0h-oriented layers.