The importance of particle size ratio and particle composition in the properties of a mixed bed is well known. Nevertheless, the dependence of the ed channel tortuosity T on the porosity ε in the form T= 1/εn, where n is assumed to be a constant, shows that the value of n depends on the properties f the packed bed. For loose packing, experimental data for binary mixtures of glass beads of a siz...

Precise prediction of particulate movement is needed to provide a better understanding of how airborne disease organisms move within ventilated facilities. Bacteria often adhere to larger airborne particulates, which will modify their movement behavior in ventilated rooms and may provide an environment to allow them to remain virulent longer. An empty chamber (206 H x 203 W x 386 cm L) with a c...

UNLABELLED The effectiveness of emissions control programs designed to reduce concentrations of airborne particulate matter with an aerodynamic diameter < 2.5 microm (PM2.5) in California's San Joaquin Valley was studied in the year 2030 under three growth scenarios: low, medium, and high population density. Base-case inventories for each choice of population density were created using a couple...

1. Lowering of the concentration of carbon dioxide in air available to phototrophically growing Euglena cultures from 5% to the normal value (0.03%) resulted in an increased specific activity of glycollate oxidoreductase. 2. The effects of chloramphenicol and cycloheximide suggested that this increase in activity was due to enzyme synthesis de novo on cytoplasmic ribosomes. 3. The K(m) for glyc...

A new method for simultaneous and independent on-line determination of bulk density and moisture content in particulate materials by measurements of the relative complex permittivity is proposed. The bulk density is determined, based on a representation in the complex plane of relative complex permittivity normalized to bulk density. For moisture content determination, a new density-independent...

IPIT initial experiments on the fractionation of mitochondria into subparticulate constituents, it became apparent that for isolation of the particles, a method more satisfactory than the customary methods of differential centrifugation was needed. The subject of this report is a simple and rapid method for obtaining relatively uncontaminated preparations of particulate cell components by gradi...

An ambient particle monitoring study was conducted in Washington, D.C. during the summer of 1994 as part of the Metropolitan Acid Aerosol Characterization Study (MAACS). Acid aerosol and inhalable (particulate matter with aerodynamic diameters < 10 micron; PM10) and fine (particulate matter with aerodynamic diameters < 2.5 micron; PM2.5) particle samples were collected for 24-hr periods (9 A.M....

Two lipases were found in extracts from castor bean (Ricinus communis L.) endosperm. One, with optimal activity at pH 5.0 (acid lipase), was present in dry seeds and displayed high activity during the first 2 days of germination. The second, with an alkaline pH optimum (alkaline lipase), was particularly active during days 3 to 5. When total homogenates of endosperm were fractionated into fat l...