5,092 research outputs found
Steady temperature and density distributions in a gas containing heat sources
Computer program, STADDIG, is based on steady state, one dimensional heat transfer calculation using cylindrical coordinates. Program allows for conduction across gas and container walls. Heat is dissipated from walls by forced convection cooling with incompressible coolant. Heat sources are included in coolant, gas, and walls
Axial power tailoring to obtain constant fuel-centerline temperature in a nuclear reactor
Axial power tailoring to obtain constant fuel- centerline temperature in nuclear reacto
Calculation of radiation induced swelling of uranium mononitride using the digital computer program CYGRO 2
Fuel volume swelling and clad diametral creep strains were calculated for five fuel pins, clad with either T-111 (Ta-8W-2.4Hf) or PWC-11 (Nb-1Zr-0.1C). The fuel pins were irradiated to burnups between 2.7 and 4.6%. Clad temperatures were between 1750 and 2400 F (1228 and 1589 K). The maximum percentage difference between calculated and experimentally measured values of volumetric fuel swelling is 60%
The control of a nuclear reactor using helium- 3 gas control elements
Control system for water moderated reactor using helium-3 ga
High-resolution pore-water sampling with a gel sampler
Sediment pore-water profiles were sampled at high resolution (millimeter scale) with a polyacrylamide gel probe. This simple procedure involves inserting a 1-mm-thick gel held in a plastic probe into sediment. The gel reaches diffusive equilibrium in <1-2 h. For anions, the gel was sectioned, back-equilibrated into distilled-deionized water, and anions determined by high-performance liquid chromatography. Laboratory trials showed recovery of 104+/-4% Cl, 102+/-2% NO3, 101+/-1% SO4, and 102+/-2% NH4. For Fe and Mn, the gel was fixed in 0.01 M NaOH for similar to 3 h, subsectioned, extracted with 1 M HNO3, and analyzed by atomic absorption spectrometry. Field trials were undertaken in Esthwaite Water, a seasonally anoxic lake in the English Lake District. Gel probe data compared well with conventional pore-water extractions
Bird observations in the Muratus Mountains, Kalimantan Selatan
A brief survey was made of birds in the Muratus Mountains, Kalimantan Selatan, in October 1996. At least 21 montane specialists occur there. These are all first records for the area, and major extensions of known range are made for Mountain Tailorbird Orthotomus cuculatus, White browed Rhinomyias Rhinomyias gularis and Black capped White eye Zosterops atricapilla
Advanced-power-reactor design concepts and performance characteristics
Five reactor cooling concepts which allow continued reactor operation following a single rupture of the coolant system are presented for application with the APR. These concepts incorporate convective cooling, double containment, or heat pipes to ensure operation after a coolant line rupture. Based on an evaluation of several control system concepts, a molybdenum clad, beryllium oxide sliding reflector located outside the pressure vessel is recommended
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Evidence for suboxic nitrification in recent marine sediments
The classical scheme of biogeochemical zones (BGZ) is known to be an oversimplification
of the microbial processes that occur in organic-rich marine sediments. Results from a coupled
deployment of pore-water gel probes in Loch Duich, Scotland, provide direct evidence for rapid
recycling within the iron reduction (FeR) and sulphate reduction (SR) zones. High resolution porewater
profiles obtained using diffusive equilibrium in thin films (DET) gel probes found a nitrate peak
at the boundary between the FeR and SR zones. This non-steady state feature is consistent with recycling
of reduced N occurring throughout the FeR zone. Both conventional pore-water iron profiles
and results from diffusive gradient in thin films (DGT) probes indicate that iron is solubilised and precipitated
in rapid Fe/S recycling reactions throughout the SR zone. The presence of such complex
recycling reactions confirms the oversimplification of the classical BGZ scheme
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