Characterization of design and economic sensitivity of vapor phase carbon adsorption systems to environmental uncertainties

Vapor phase carbon adsorption systems are used to remove aromatics, aliphatics, and halogenated hydrocarbons. The adsorption capacity of granular activated carbon is reduced when environmental parameters (temperature, pressure, and humidity) interfere with homogeneous surface diffusion and pore distribution dynamics. The purpose of this study was to investigate the effects of parametric uncertainties in adsorption efficiency. ^ Modified versions of the Langmuir isotherm in conjunction with thermodynamic equations described gaseous adsorption of single component influent onto microporous media. Experimental test results derived from Wang et al. (1999) simulated adsorption kinetics while the Myer and monsoon Langmuir constant accounted for isothermal gas compression and energetic heterogeneity under thermodynamic equilibrium conditions. Responsiveness of adsorption capacity to environmental uncertainties was analyzed by statistical sensitivity and modeled by breakthrough curves. Results indicated that extensive fluctuations in adsorption capacity significantly reduced carbon consumption while isothermal variations had a pronounced effect on saturation capacity. ^

Customer Perception of Drive-Thru Service

The rapid growth of off-premise dining and, consequently, drive- thru service, presents the challenge of building customer loyalty in a highly competitive marketplace. In this study, customer perceptions of drive-thru service associated with quick service restaurants were examined. Results suggest that service time appears to differ among quick service restaurants, even those within the same chain. Employee courtesy was rated positively at all restaurants, as was food quality. The implications of these results for restaurateurs who offer drive-thru service are discussed.