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“BACKGROUND: In order to improve the performance of a counter-current bubble column, radial variations of the gas hold-ups and mean hold-ups were investigated in a 0.160 m i.d. bubble
column using electrical resistance tomography with two axial locations (Plane 1 and Plane 2). In all experiments the liquid phase was tap water and the gas phase air. The superficial gas velocity was varied from 0.02 to 0.25 m s(-1), and the liquid velocity varied from 0 to 0.01 m s(-1). The effect of liquid velocity HDAC inhibitor on the distribution of mean hold-ups and radial gas hold-ups is discussed.
RESULTS: The gas hold-up profile in a gas-liquid counter-current bubble column was determined by electrical resistance tomography. The liquid velocity slightly influences the mean hold-up and radial hold-up distribution under the selected operating conditions and the liquid flow improves the transition gas velocity from a homogeneous
regime to a heterogeneous regime. Meanwhile, the radial gas hold-up profiles are steeper at the central region of the column with increasing gas velocity. Moreover, the gas hold-up in the centre of the column becomes steeper with increasing liquid velocity.
CONCLUSIONS: The value of mean gas hold-ups slightly increases with increasing Selleck HIF inhibitor downward liquid velocity, and more than mean gas hold-ups in batch and co-current operation. According to the experimental results, an empirical correlation for the centreline gas hold-up is obtained based on the effects of gas velocity, liquid velocity, and ratio of axial height to column diameter. The values calculated in this way are in close agreement with experimental data, and compare with literature data on gas hold-ups at the centre of the column. (C) 2010 Society AZD1480 molecular weight of Chemical Industry”
“Background and objective: The assessment of static lung volumes and airway resistance is a frequently performed diagnostic procedure and considered as an important tool in medical surveillance to detect pulmonary diseases. The objectives of the study are to establish reference equations for body plethysmographic parameters in a representative adult population across a wide age
range and to compare the normative values from this sample with previous ones.
Methods: Body plethysmography was applied in 1809 participants (885 males) of a cross-sectional, population-based survey (Study of Health in Pomerania). Individuals with cardiopulmonary disorders and/or a pack-year smoking history >10 years and participants with a body mass index >30 kg/m(2) were excluded. In total, 686 healthy individuals (275 males) aged 25-85 years were assessed.
Results: Prediction equations for both genders were established by quantile regression analysis taking into account the influence of age, height and weight.
Conclusions: The study provides a novel set of prediction equations for static lung volumes and airway resistance obtained using body plethysmography.