Air flow resistivity

The effect of the device on air flow resistance and the ability of patients to achieve the necessary air flow rate for proper use of the product should be considered. The in vitro test method should also take this into account since the results obtained may be dependent on air flow characteristics. 

Analogous to sampling TIN with the filter pack method, sampling with a quartz- or glass-fiber filter followed by a sorbent can provide a relatively accurate measure of the total (i.e., vapor plus particle phase) concentration of specific PAH compounds. Such methodologies were reviewed by Lee et al. (73). Selection of a sorption medium for collection of vapor-phase PAHs is influenced by air-flow resistance, collection efficiency, breakthrough volume, the effort required to purify the medium for use, and the efficiency with which the PAH can be recovered from the sorbent. 

Hermansen L, Vokac Z and Lereim P (1972). Respiratory and circulatory response to added air flow resistance during exercise. Ergonomics, 15, 15-24. 

Guinea pigs administered 0.73 mg zinc/m as zinc oxide for 1 hour had a progressive decrease in lung compliance but no change in air flow resistance. These observations reflect a response in the lung periphery where submicrometer aerosols are likely to deposit (Amdur et al. 1982). The authors postulated that reduced compliance may be associated with human metal fume fever. 

Researchers have reported some properties of electrospun mats. They compared the performances of electrospun fibre mats with the properties of textiles and membranes currently used in protective clothing systems and showed that electrospun layers are extremely efficient for trapping airborne particles. Meanwhile, the air flow resistance and aerosol filtration properties are affected by the coating weight. It was shown that an extremely thin layer of electrospun nanofibres completely prevented particle penetration through the layer. 

A 14° section of the containment was built with 1 6 scaling factor to quantitatively assess the air flow resistance. This resulted in modification of the air inlet and exhaust to be a rounded entrance and a rounded air baffle supports. 

Good heat recovery is possible only if the cooler is operated with a deep bed of clinker, with a correspondingly high air flow resistance. For this reason the fans in the hot zone should be able to develop a sufficiently high pressure. The required minimum pressures for the fans supplying air to the recuperative zone are as follows ... 

Most textiles that are used for acoustic purposes show open porosity due to many interconnected pores or voids inside. The acoustic performance of a porous textile is mainly determined by its (air) flow resistivity, which is an intrinsic property of the textile and is a measure of how easily air can enter and pass through a porous textile material (Cox and D Antonio, 2009). Flow resistivity, also known as static flow resistivity, is related to acoustical properties and plays a critical role in the calculation of many intrinsic acoustic properties of porous textiles, such as the characteristic impedance, the propagation constant, and the sound absorption coefficient. In the S.l. Unit system, flow resistivity is quoted in units of Nsm" and is defined as the unit-thickness specific flow resistance o (Morfey, 2001),... 

The air sub-model has two components the inertia of the air above the reed and the (nonlinear) air flow resistance labelled I r and R r, respectively. The former is the straightforward bond graphs I component (mass) considered earlier, but the other component is more complex, as the flow resistance is modulated by the reed position. Thus R r is not the simple R component (dumper) but rather an Effort-Modulated Resistor (EMR) component (Figure 4.23) which is modulated by the displacement of x of the reed please refer to book by Gawthrop and Smith (1996) for more information on bond graphs components. The fact that displacement appears as an effort in this context is a result of the way we have chosen to model the system. The constitutive relationship embedded in this EMR component follows de Bruin and van Walstijn s description (1995). 

The wind channel test will research air flow resistance characteristic and effects of air channel shape and air inlet location on natural circulation flow. 

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