Resource Type

Enhancement of methane production in the anaerobic digestion of sewage sludges (open access)

Enhancement of methane production in the anaerobic digestion of sewage sludges

The effect of powdered activated carbon on stressed anaerobic digesters utilizing a sewage sludge substrate was evaluated. The addition of carbon resulted in increased methanee production and greater process stability. The degree of enhancement appeared to be proportional to carbon concentration over the dose range studied (500-10,000 mg/l). A maximum increase in methane production of about 150% was observed at the highest carbon dose. The effect of 1500 mg/l carbon, 4000 mg/l coal, and 4000 mg/l flyash on relatively unstressed digesters was also examined. Units using a sewage sludge substrate were operated at 10 and 20 day SRT's. A 12% increase in methane production was observed in a carbon dosed digester functioning at a 10 day detention time. Enhancement was not evident with carbon at a 20 day SRT. No significant improvement in methane production was obtained in any of the digesters using coal or flyash as additives. Using the experimental data, a technique was developed for estimating the efficiencies of the methane forming and acid forming steps in the anaerobic digestion process. The results indicated that in stressed systems both stages of the digestion process were enhanced by the addition of powdered carbon. In the relatively unstressed systems, when …
Date: May 10, 1978
Creator: Spencer, R. R.
System: The UNT Digital Library
EMP protection technology interchange (open access)

EMP protection technology interchange

Investigation and assessment of the potential degrading and destructive effects associated with the nuclear electromagnetic (EMP) phenomena has created a large technological base. This base is indeed quite broad owing to the unique and system-pervasive character of the EMP. One of the aims of an emerging discipline, such as that associated with EMP, is to provide for adequate transfer and integration of the developing technology into the overall engineering community. The needs of the community and how EMP hardening and protection information can be transferred or exchanged are reviewed. Many of the current and generally available sources of information are listed, examples of interchange methods are provided, and problems of developing specifications, standards, and suitable guidelines for design and incorporation of protection are also discussed.
Date: May 10, 1977
Creator: Martin, L. C.
System: The UNT Digital Library
Diffusion due to a single wave in a magnetized plasma (open access)

Diffusion due to a single wave in a magnetized plasma

Hamiltonian methods are used to study the motion of a particle in the field BZ and a single electrostatic wave. The particle motion is studied by numerically integrating the equations of motion. Diagrams of various particle trajectories are given. (MOW)
Date: May 10, 1976
Creator: Smith, G. R. & Kaufman, A. N.
System: The UNT Digital Library
Peripheral thresholds and Regge asymptotic expansions (open access)

Peripheral thresholds and Regge asymptotic expansions

None
Date: May 10, 1974
Creator: Chew, G. F. & Koplik, J.
System: The UNT Digital Library