ansi/ashrae 110-95 protocol is a widely acceptable method to assess the performance of laboratory hoods. in this test, sulfur hexafluoride (sf6) is applied as a tracer gas to quantitatively evaluate the performance of laboratory hoods. the environmentally hostile characteristics of sf6 as well as its cost are the major concerns. in the present study, the substitution of ethylene with sf6 in the...

background and objective : a considerable amount of sulfur hexafluoride is applied to evaluate the performance of each laboratory hood according to ashrae–110-95 method. sf 6 is extremely hostile to environment and expensive. in present work, the possibility of conducting this method of hood performance test with less volume of sf 6 was investigated. material and methods : the performance of a ...

ANSI/ASHRAE Standard 110 provides a quantitative method for testing the performance of laboratory fume hoods. Through release of a known quantity (4.0 Lpm) of a tracer gas, and subsequent monitoring of the tracer gas concentration in the "breathing zone" of a mannequin positioned in front of the hood, this method allows for evaluation of laboratory hood performance. Standard 110 specifies sulfu...

The photoacoustic effect may be exploited for the detection and localization of gas leaks from otherwise sealed components. The technique involves filling the test component with a tracer gas, and radiating the component to produce photoacoustic sound from any leak site where tracer gas is present. This paper describes demonstration experiments utilizing 10.6-micro radiation from a carbon-dioxi...

Lu Han and Muthanna H. Al-Dahhan A gaseous tracer technique and procedures were developed and implemented to measure the axial dispersion of gas phase in a slurry bubble column reactor using air-water-glass beads (100ìm). Residence time distribution curves were obtained by measuring the response of gaseous tracer pulse input. The gas phase axial dispersion coefficient, Dg, was determined from m...

Ventilation is essential to the health and comfort of occupants in enclosed spaces. However, it is difficult to accurately measure the ventilation rates in large, long, and narrow spaces such as aircraft cabins and train compartments. This study proposed a modified tracer-gas-concentration decay method that combined the multi-zone technique and genetic algorithm to determine ventilation rate in...

It has been recently argued that the HCN J=1–0 line emission may not be an unbiased tracer of dense molecular gas (n & 10 cm) in Luminous Infrared Galaxies (LIRGs: LFIR > 10 11 L⊙) and HCO + J=1–0 may constitute a better tracer instead (Graciá-Carpio et al. 2006), casting doubt into earlier claims supporting the former as a good tracer of such gas (Gao & Solomon 2004; Wu et al. 2006). In this p...

Greenhouse gas mitigation at landfills by methane oxidation in engineered biocover systems is believed to be a cost effective technology, but so far a full quantitative evaluation of the efficiency of the technology in full scale has only been carried out in a few cases. A third generation semi-passive biocover system was constructed at the AV Miljø Landfill, Denmark. The biocover system was fe...

Abstract. Several sulfur hexafluoride (SF6) tracer gas experiments were conducted in a subway system to measure the possible pathways of toxic gas for subway tunnels and stations empirically. A new mobile integrated measuring and analysis system was used to achieve high sample rates and a long measurement time. Due to the mobility of the sensors, tracer gas experiments were also carried out ins...