Bench scale kinetic experiments were conducted to examine the use of cell immobilization in calcium alginate to remove ammonia in anaerobic sludge digester supernatant. Two systems, immobilized nitrifiers and co-immobilized nitrifiers and denitrifiers, were studied with and without the addition of methanol. Results indicated that partial nitrification (to nitrite) was achieved in both systems. The co-immobilized reactors did not exhibit the extent of nitrite accumulation observed in the solely nitrifying reactors. The nitrifying reactors were unable to buffer the hydrogen ion production, during the nitrification process, to the level the co-immobilized cell reactors achieved. Both of these differences suggested the occurrence of denitrification in the coimmobilized reactors. Scanning electron microscopic images of bacteria immobilized in the alginate spherical beads support the results of the kinetic experiments. Nitrifiers colonized in the 100-200 μm peripheral layer of the beads. Large voids caused by nitrogen gas due to denitrification were found in a number of co-immobilized bead samples.

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In this work, the impact behavior of the electrified carbon fiber reinforced polymer (CFRP) composites with carbon nanotube (CNT) buckypaper layers has been studied. A custom-built experimental setup that allows for real time measurements of pulsed electric current, voltage, load, and velocity during coordinated application of a current pulse with an impact load was utilized. The experimental setup included a current pulse generator capable of producing a 30 millisecond current pulse with an amplitude of up to 2500 A. The application of the peak of the current pulse was coordinated with the peak of the impact load. A series of electrical, impact, and coordinated electrical-impact characterization tests were performed on three types of samples: 16-ply IM7/977-3 unidirectional laminates; laminates containing four layers of buckypaper (BP) and 12 unidirectional IM7/977-3 layers arranged as CF 2 /BP/CF 4 /BP/CF 4 /BP/CF 4 /BP/CF 2 ; and laminates containing seven layers of buckypaper and nine unidirectional IM7/977-3 layers arranged as [CF 2 /BP] 7 /CF 2 . The results show that addition of buckypapers can lead to the increased impact resistance of CFRP composites.

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