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Physical Sciences and Mathematics Commons

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Engineering

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Iowa State University

Selected Works

1996

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Построение Редуцированного Физического Гамильтониана Для Сферически-Симметричной Гравитации, Николай Заркевич Jun 1996

Построение Редуцированного Физического Гамильтониана Для Сферически-Симметричной Гравитации, Николай Заркевич

Nikolai A. Zarkevich

No abstract provided.


Electronic Origins Of Ordering In Multicomponent Metallic Alloys: Application To The Cu-Ni-Zn System, J. D. Althoff, Duane D. Johnson, F. J. Pinski, J. B. Staunton Apr 1996

Electronic Origins Of Ordering In Multicomponent Metallic Alloys: Application To The Cu-Ni-Zn System, J. D. Althoff, Duane D. Johnson, F. J. Pinski, J. B. Staunton

Duane D. Johnson

We investigate the ordering tendencies of the fcc Cu-Ni-Zn system using a recently developed first-principles, density-functional-based theory of atomic short-range order (ASRO) in disordered substitutional alloys of an arbitrary number of components. We find for the binary alloys a variety of effects which should lead to competition in the ternaries: commensurate ordering (Ni-Zn), long-period ordering (Cu-rich Cu-Zn), and clustering (Cu-Ni), in agreement with experiment. We calculate the ASRO of various disordered ternary alloys (as described by the Warren-Cowley pair-correlation function) and discuss its relationship to the electronic structure of the binary and ternary disordered alloys. We find [100]-type ASRO over …


Nutrient Mapping Implications Of Short-Range Variability, Stuart J. Birrell Jan 1996

Nutrient Mapping Implications Of Short-Range Variability, Stuart J. Birrell

Stuart J. Birrell

Successful site specific nutrient application depends on accurate soil nutrient maps, which are generally developed from grid samples. The implication of short range variability for soil nutrient mapping is investigated. Interpretation of soil nutrient maps must consider the level of confidence associated with estimated values.


Analysis Of Spatial Factors Influencing Crop Yield, K. A. Sudduth, S. T. Drummond, Stuart J. Birrell, N. R. Kitchen Jan 1996

Analysis Of Spatial Factors Influencing Crop Yield, K. A. Sudduth, S. T. Drummond, Stuart J. Birrell, N. R. Kitchen

Stuart J. Birrell

The spatial relationship between crop yields and soil and site parameters was modeled using several methods. Yield maps estimated by projection pursuit regression and neural network analysis agreed well with measured yields. These methods also allowed generation of response curves for estimated yield as a function of each of the input parameters. These response curves were useful for investigating the relationship between yields and individual soil and site parameters.