OBJECTIVES Study was conducted to assess whether temporal variation exists in airborne microbial concentrations of a hospital ward (west-Chennai, India) using active and passive methods, and characterise the microorganisms. METHODS Air samples (duplicates) were collected simultaneously using exposed-plate, impingement (BioSampler) and filtration (personal sampling filter cassette loaded with ...

This paper presents novel micromachined two-dimensional array piezoelectrically actuated flextensional transducers that can be used to generate sound in air or water. Micromachining techniques to fabricate these devices are also presented. Individual unimorph array elements consist of a thin piezoelectric annular disk and a thin, fully clamped, circular plate. We manufacture the transducer in t...

This paper revisits the classical problem of convectively driven one-dimensional (parallel) flow along an infinite vertical plate. We consider flows induced by an impulsive (step) change in plate temperature and by a sudden application of a plate heat flux. Provision is made for pressure work and vertical temperature advection in the thermodynamic energy equation, processes that are generally n...

Kim, M.H., Kim, S.M., Kim, C.S., Park, S.J., Lee, C.H. and Rhee, J.Y. 2002. Quality of Korean ginseng dried by a prototype continuous flow dryer using far infrared radiation and hot air. Canadian Biosystems Engineering/Le génie des biosystèmes au Canada 44: 3.473.54. This study was performed to examine the effects of infrared (IR)/hot-air combination drying on some quality attributes of Korean ...

Lotus, Nelumbo nucifera, posses a specialised efflux organ in the centre of their leaves, which connects the gas canals in the leaves and stems with the atmosphere through the apertures of large stomata. The role of these large central plate stomata in regulating air flow through the gas canals were examined on excised leaves and on intact plants in situ. The stomata show a diurnal cycle, closi...

A portable wiltmeter instrument to estimate leaf turgor pressure according to an adaptation of the flattening method was developed. In the instrument, a flexible inflating membrane presses the leaf against a flattening plate having small orifices surrounded by a finely engraved network of obtuse indentations through which air flow is delivered. During a measurement, as the compression builds up...

There is growing evidence in the epidemiologic literature of the relationship between air pollution and adverse health outcomes. Prediction of individual air pollution exposure in the Environmental Protection Agency (EPA) funded Multi-Ethnic Study of Atheroscelerosis and Air Pollution (MESA Air) study relies on a flexible spatio-temporal prediction model that integrates land-use regression with...

Mutagenic activity of extractable organic matter (EOM), from airborne particles collected over winters in four towns of Czech Republic, was investigated by the means of Salmonella typhimurium indicator strains TA98 and YG1041 using the Ames plate incorporation assay. Mutagenicity of all tested samples showed significant dose-related increase in number of revertants per mg of EOM. The direct mut...

The well known zero in the group velocity of the first-order symmetric (S1) plate wave mode has been exploited in air-coupled ultrasonic imaging to obtain significantly higher sensitivity than can be achieved in conventional air-coupled scanning. At the zero group velocity point at the frequency minimum of the S1 mode, a broad range of wavenumbers couple into the first-order symmetric mode at n...

The present thesis aims to study the effect of human movements on local exhaust ventilation. In its simplest terms, local exhaust ventilation is a system which has the function of extracting contaminated air situated close to the contaminant source, protecting a working person from exposure to hazardous substances by containing or capturing them locally, at the emission point. As an important s...