Fuzzy logic feedback control for fed-batch enzymatic hydrolysis of lignocellulosic biomass.

A fuzzy logic feedback control system was developed for process monitoring and feeding control in fed-batch enzymatic hydrolysis of a lignocellulosic biomass, dilute acid-pretreated corn stover. Digested glucose from hydrolysis reaction was assigned as input while doser feeding time and speed of pretreated biomass were responses from fuzzy logic control system. Membership functions for these three variables and rule-base were created based on batch hydrolysis data. The system response was first tested in LabVIEW environment then the performance was evaluated through real-time hydrolysis reaction. The feeding operations were determined timely by fuzzy logic control system and efficient responses were shown to plateau phases during hydrolysis. Feeding of proper amount of cellulose and maintaining solids content was well balanced. Fuzzy logic proved to be a robust and effective online feeding control tool for fed-batch enzymatic hydrolysis.

Decreased nasal mucosal sensitivity in older subjects.

BACKGROUND: The sensitivity of the human nasal cavity mucosa to touch is not well understood. The site of receptors and mode of action responsible for the sensation of the nasal airflow is a topic of controversy. Previous studies have suggested that the skin-lined nasal vestibule is more sensitive to airflow than the mucosa of the nasal cavity. A possible decline in nasal sensitivity to airflow in older subjects has not been studied. METHODS: The threshold of the mucosal sensitivity to jets of air was assessed in 76 subjects with healthy nasal cavities. A total of 141 nostrils were tested, 67 in younger patients and 74 in older patients. RESULTS: Statistically significant (p < 0.001) increases in thresholds were found for all points tested for older patients compared with the younger patients. In general, the more sensitive locations were in the nasal vestibule. The nasal cavity mucosa in the inferior meatus was slightly more sensitive than the middle meatus. CONCLUSION: We have measured the threshold to touch (air jet sensitivity) in nine places in each of 141 nasal cavities and determined that the variability and sensitivity of these measurements among people varies by age and the distance from the nostril. Older subjects were found to have a higher threshold for the sensation of airflow, and the nasal vestibule was found to be more sensitive than the rest of the nasal cavity mucosa with the inferior meatus slightly more sensitive then the middle meatus.