Denitrifying population dynamic and evolution of nitrogen gas during a composting process

Abstract

Little information exists about nitrogen losses through microbial activity during treatment of solid urban waste (SUW) by processes such as composting. In the present study, in addition to evaluating the pattern of nitrogen losses by denitrification at different stages of the process, a comparison between the method of Pochon and Tardieux, and an improved gas chromatographic method for estimating denitrifying populations was undertaken. Though the MPN (Most Probable Number) enumerations were higher using the colorimetric method than the gas chromatographic one, the pattern of the two graphs showing numbers of denitrifiers during composting were the same. The highest numbers were revealed immediately after loading the reactor (107-108/g d.w.), lower numbers of denitrifiers were found in the second sampling corresponding to the thermophilic phase (103-104/g d.w.). These numbers increased gradually as the waste material stabilized (10th to 123rd day of composting) to again reach values of 107-108/g d.w

Physical mechanism study of N-well doping effects on the single-event transient characteristic of PMOS

“…Thus it is necessary to study the physical mechanism of bulk area effect on the SET character of transistors in bulk silicon technology. Previous research indicates that parasitic bipolar amplification effect is the primary cause of the SET pulse-width broading in PMOS [7,8]. Furtherly, well potential plays an important role in this effect [9,10], for the ion strike into transistor, the parasitic bipolar transistor is activated by well potential collapse.…”