High Nitrogen Concentration in Fe-Cr-Ni Alloys

1991 ◽  
Vol 251 ◽  
Author(s):  
James C. Rawers ◽  
Nev A. Gokcen ◽  
Robert D. Pehlke
Keyword(s):  
High Pressure ◽  
Nitrogen Concentration ◽  
Weight Percent ◽  
Published Data ◽  
High Nitrogen ◽  
Concentration Data ◽  
Statistical Correlations ◽  
Nitrogen Concentrations ◽  
Pressure Melting ◽  
Percent Nitrogen

ABSTRACTIncreasing the nitrogen concentration in iron and iron alloys significantly improves their mechanical properties. A recent technique for melting in a hot-isostatic pressure furnace using nitrogen as the pressurizing gas has been developed by U.S. Bureau of Mines researchers for making massive nitrogen additions to iron (up to 1.6 weight percent nitrogen) and iron-chromium-nickel alloys (up to 6.6 weight percent nitrogen). The total nitrogen concentration measured at atmospheric pressure and room temperature was determined to be the equilibrium nitrogen concentration in the molten alloy. Statistical correlations were derived to explain the effects of melt pressure and alloy composition on the resulting nitrogen concentration. Nitrogen concentrations measured in solidified alloys made by high pressure melting techniques at lower pressures are consistent with previous published data. Computer generated phase diagrams for high nitrogen-chromium concentrations are also consistent with nitride microstructure observed after high-pressure melting. Extension of existing atmospheric nitrogen concentration data to higher pressure nitrogen concentrations shows Sievert's law (nitrogen concentration is proportional to the square root of the nitrogen melt pressure) to be valid for pure iron. However, substantial deviations from Sievert's law are observed for higher alloy compositions. Statistical fits of thermodynamic concentration data to the high-pressure melt nitrogen data requires evaluating element concentration terms, interaction effect terms, pressure terms, and pressure-composition effects terms. Examination of the nitrogen concentration data suggests several methods of correlation.

Mechanical and microstructural properties of nitrogen–high pressure melted Fe–Cr–Ni alloys

1992 ◽  
Vol 7 (5) ◽  
pp. 1083-1092 ◽  
Author(s):  
J. Rawers ◽  
G. Asai ◽  
R. Doan ◽  
J. Dunning
Keyword(s):  
High Pressure ◽  
Nitrogen Concentration ◽  
Nitrogen Pressure ◽  
Nitrogen Atmosphere ◽  
Ni Alloys ◽  
Nitrogen Concentrations ◽  
Iron Chromium Nickel Alloys ◽  
Pressure Melting ◽  
Mechanical And Microstructural Properties ◽  
Iron Chromium

A series of iron-chromium-nickel alloys was melted under a nitrogen atmosphere at several different pressures. Nitrogen–high pressure melting (N–HPM) was conducted under pressures ranging from 0.1 to 200 MPa. The total nitrogen concentrations achieved in these alloys were proportional to the square root of the nitrogen pressure used during melting. Nitrogen took the form of soluble interstitial nitrogen and metal nitride precipitates, FexN and CrN. Tensile properties of N–HPM alloys were directly proportional to the nitrogen concentration in the alloy.

Seasonal fluctuations in river bacteria as measured by multivariate statistical analysis of continuous cultures

1982 ◽  
Vol 28 (8) ◽  
pp. 959-975 ◽  
Author(s):  
Colin R. Bell ◽  
Maxine A. Holder-Franklin ◽  
Mervyn Franklin
Keyword(s):  
Statistical Analysis ◽  
Continuous Culture ◽  
Culture Medium ◽  
Nitrogen Concentration ◽  
Diversity Analysis ◽  
Seasonal Fluctuations ◽  
High Nitrogen ◽  
Continuous Cultures ◽  
Multivariate Statistical ◽  
Nitrogen Concentrations

Forty-eight continuous culture enrichments were performed on summer and winter water samples from two contrasting rivers. The cell output from each chemostat was dependant on the temperature and nitrogen concentration of each enrichment. The diversity of the populations from the continuous cultures, as assessed by species diversity analysis, was always greater than populations obtained on agar plates. However, the species isolated exclusively by continuous culture in these experiments were not unique to the chemostat. All of these species had been isolated at some time on plates directly. High nitrogen concentrations were found to decrease diversity. Populations sampled during the winter were influenced primarily by the concentration of nitrogen. Summer isolates were affected mainly by the temperature of the culture medium. The nutritional versatility of the population was not affected by enrichment of the continuous culture.

Formation of High Quality Oxynitride Gate Dielectrics by High Pressure Thermal Oxidation of Si in NO

1999 ◽  
Vol 567 ◽  
Author(s):  
S. C. Song ◽  
C. H. Lee ◽  
H. F. Luan ◽  
D. L. Kwong ◽  
M. Gardner ◽  
...  
Keyword(s):  
High Pressure ◽  
Gate Dielectrics ◽  
Nitrogen Concentration ◽  
Budget Process ◽  
High Nitrogen ◽  
High Quality ◽  
Thermal Budget ◽  
Hot Carrier ◽  
Low Thermal Budget ◽  
High Nitrogen Concentration

ABSTRACTIn this paper, we report a novel low thermal budget process (<800°C) for engineered ultra thin oxynitride dielectrics with high nitrogen concentration (>5% a.c.) using vertical high pressure (VHP) process. VHP grown oxynitride films show >1 OX lower leakage current, higher drive current and superior hot-carrier reliability compared to control SiO2 of identical thickness (Tox,eq) grown by RTP in O2.

Nitrogen in temperate crop and pasture plants

1975 ◽  
Vol 26 (1) ◽  
pp. 103 ◽  
Author(s):  
JS Gladstones ◽  
JF Loneragan
Keyword(s):  
Nitrogen Concentration ◽  
Trifolium Subterraneum ◽  
Lolium Rigidum ◽  
High Nitrogen ◽  
Pasture Legumes ◽  
Ornithopus Compressus ◽  
Nitrogen Concentrations ◽  
Three Stages ◽  
Erodium Botrys ◽  
Pasture Plants

Nitrogen concentrations were determined in the tops of 24 annual crop and pasture varieties grown together in ungrazed plots on a lateritic gravelly sand at Gidgegannup, W.A., and sampled at three stages during growth and at maturity. All legumes had higher nitrogen concentrations in the tops than all non-legumes, but considerable variation was evident within each group. Among pasture legumes, Ornithopus compressus and O. sativus had the highest concentrations, especially towards maturity, and Trifolium subterraneum cv. Yarloop and Clare the lowest. Nitrogen concentrations in all Lupinus spp. fell rapidly towards maturity, and they were unique in suffering substantial net nitrogen losses from the tops. The herb Erodium botrys grew better and took up more nitrogen under conditions of deficiency than did the grasses. Its nitrogen concentration was nevertheless very low. Among the grasses, Bromus rigidus consistently had the highest nitrogen concentration and Lolium rigidum the lowest. There was some evidence among non-legumes of a correlation between high nitrogen concentrations and/or total uptake and observed adaptation to sandy soils. The superior adaptation of legumes in the experimental environment was demonstrated. It is suggested that crop legumes could make a more important agronomic contribution than hitherto in this and similar environments.

Research of Flow Simulation with High-Pressure and Bottom-Blowing Nitrogen

2013 ◽  
Vol 634-638 ◽  
pp. 3110-3113
Author(s):  
Shu Huan Wang ◽  
He Jun Zhang ◽  
Ding Guo Zhao
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Molten Steel ◽  
Gas Content ◽  
High Nitrogen Steel ◽  
High Nitrogen ◽  
Nitrogen Steel ◽  
Bottom Blowing ◽  
Steel Flow ◽  
Pressure Factor

According to the actual situation of refining high nitrogen steel with the laboratory high pressure reaction axe, the molten steel flow field in the high-pressure and bottom-blowing nitrogen reactor was simulated by using the software Fluent. The rules of the influence of pressure factor on the molten steel flow field characteristics, turbulent kinetic energy and gas content were explored. According to the characteristics of the flow field and gas-liquid two phase structure, the rules of the influence of pressure factor on nitrogen concentration distribution were analyzed. So some useful theoretical basis and guidance were provided for laboratory refining high nitrogen steel and industrial production in the future.

Nitrogen cycling in a Venezuelan tropical seasonally flooded forest: soil nitrogen mineralization and nitrification

1994 ◽  
Vol 10 (3) ◽  
pp. 399-416 ◽  
Author(s):  
Barrios E. ◽  
Herrera R.
Keyword(s):  
Soil Nitrogen ◽  
Nitrogen Availability ◽  
Inorganic Nitrogen ◽  
Nitrogen Concentration ◽  
Ammonium Nitrogen ◽  
Wet Season ◽  
Flooded Forest ◽  
Nitrogen Concentrations ◽  
Minimum Stress ◽  
Seasonally Flooded

ABSTRACTSeasonally flooded forests represent a transition between terrestrial and aquatic ecosystems. The Mapire river, a tributary of the Orinoco river, floods its surrounding forests during the wet season (May–December). The soils are very acid and the total nitrogen concentration (0.1%) is only half that found in nearby soils flooded by Orinoco waters. Ammonium-nitrogen predominates in the soil during the flooded period while nitrate-nitrogen concentrations are higher in the dry period. Wide fluctuations in the inorganic nitrogen fractions did not considerably affect the annual course of soil nitrogen.The predominance of mineralization versus nitrification (56 and 5 μgsoil month−1respectively) and possibly the synchronization of nitrogen availability with plant demand could be considered as nitrogen conserving mechanisms.In synchrony with the hydrologic cycle, the seasonally flooded forest studied shows a nitrogencycle where inputs and accumulation are maximized when the system is under minimum stress (dry season). During flooding, the system enters a period of dormancy making minimal use of nutrient and energy to avoid or tolerate anaerobiosis.

scholarly journals The Fitness Advantage of Commercial Wine Yeasts in Relation to the Nitrogen Concentration, Temperature, and Ethanol Content under Microvinification Conditions

2013 ◽  
Vol 80 (2) ◽  
pp. 704-713 ◽  
Author(s):  
Estéfani García-Ríos ◽  
Alicia Gutiérrez ◽  
Zoel Salvadó ◽  
Francisco Noé Arroyo-López ◽  
José Manuel Guillamon
Keyword(s):  
Abiotic Factors ◽  
Nitrogen Concentration ◽  
Wine Yeast ◽  
Wine Industry ◽  
Wine Yeasts ◽  
Simple Method ◽  
Fitness Advantage ◽  
Yeast Strains ◽  
Industrial Strains ◽  
Nitrogen Concentrations

ABSTRACTThe effect of the main environmental factors governing wine fermentation on the fitness of industrial yeast strains has barely received attention. In this study, we used the concept of fitness advantage to measure how increasing nitrogen concentrations (0 to 200 mg N/liter), ethanol (0 to 20%), and temperature (4 to 45°C) affects competition among four commercial wine yeast strains (PDM, ARM, RVA, and TTA). We used a mathematical approach to model the hypothetical time needed for the control strain (PDM) to out-compete the other three strains in a theoretical mixed population. The theoretical values obtained were subsequently verified by competitive mixed fermentations in both synthetic and natural musts, which showed a good fit between the theoretical and experimental data. Specifically, the data show that the increase in nitrogen concentration and temperature values improved the fitness advantage of the PDM strain, whereas the presence of ethanol significantly reduced its competitiveness. However, the RVA strain proved to be the most competitive yeast for the three enological parameters assayed. The study of the fitness of these industrial strains is of paramount interest for the wine industry, which uses them as starters of their fermentations. Here, we propose a very simple method to model the fitness advantage, which allows the prediction of the competitiveness of one strain with respect to different abiotic factors.

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