ABSTRACT
The isosteric heats of adsorption of the components of a gas mixture are critical variables for design of adsorbers for gas separation. They can be unambiguously defined by the Gibbsian Surface Excess (GSE) model of multicomponent adsorption. These variables can be experimentally measured by multicomponent differential calorimetry (MDC) and directly used to describe nonisothermal behavior of practical adsorbers. There is no need to make simplified assumptions about the nature and size of the adsorbed phase, as required by conventional adsorption thermodynamic models, to define the isosteric heats. Pure gas isosteric heats of adsorption of N2 and CO2 on a pelletized silicalite sample were measured using a MDC and a data analysis algorithm based on the GSE model. The silicalite sample behaved like a homogeneous adsorbent for weakly polar N2 adsorption. The presence of polar alumina binder in the silicalite sample introduced significant heterogeneity for more polar CO2 adsorption.
ABSTRACT
The pedal pulses of 547 young healthy subjects were examined using digital palpation and a Doppler probe to determine the incidence of congenitally absent foot pulses. The posterior tibial (PT) pulse was absent in only one subject (0.18%), while the dorsalis pedis (DP) pulse was bilaterally absent in nine subjects (1.8%) and unilaterally absent in a further six subjects. The low incidence of congenital absence makes the clinical finding of an absent pedal pulse in later life a more significant marker of peripheral vascular disease than current surgical texts would have us believe.
