No abstract

A significant drawback to ammonia borane as a hydrogen storage material is the production of ammonia gas during hydrolysis. As a possible solution, maleic acid is shown to be capable of fully promoting hydrolysis of ammonia borane while also preventing ammonia release in excess of single digit parts per million. The reaction is shown to be relatively insensitive towards common water contaminants, with seawater, puddle water, and synthetic urine resulting in hydrogen evolution comparable to that observed when using highly pure deionized water. A common cola beverage was also investigated as a potential water source, with results deviating from those observed when using the other water sources. The ability to use low quality water sources presents the option of acquiring water at the point of use, greatly increasing the energy density of the system during transportation. For each of the water sources being used, concentrations of ammonia in the gas products of maleic acid-promoted hydrolysis were found to be less than the lower detection limits of the employed analysis methods. Based on this reaction, a portable hydrogen reactor is reported and shown to be capable of on-demand hydrogen generation sufficient to power a proton exchange membrane fuel cell at varying loads without significant changes in system pressure. The overall power production system has substantial value in scenarios where electrical power is required but there is no access to an established electrical utility, with prime examples including disaster relief and expeditionary military operations.

No abstract

No abstract

The study of the physics of human voice production has benefited by the use of synthetic human vocal fold replicas. Extending this concept to avian vocalization, a functioning model of a male mallard syrinx for studying the relationship between syrinx anatomical features and vocalization characteristics is described here. The mallard syrinx is characterized by two sets of labia located at the tracheobronchial juncture, and vocalization is produced by the flow-induced vibration of these labia. Shape and histological composition of labia demonstrate similarities to mammalian vocal folds. In this study, life-sized synthetic replicas based on CT data of an adult male mallard syrinx, including airway and labia regions, are studied. The replicas are fabricated using exceedingly flexible silicone materials that have been previously used in synthetic human vocal fold replicas. The replicas are mounted in tube-like airways representing the trachea and bronchi, with flow generated by an adjustable air supply. In this presentation, the CT-based syrinx model, including fabrication process, will be introduced. The model response, including acoustical output and vibratory motion, will be described and compared to previous models and to existing data about mallard vocalization.