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Full-Text Articles in Engineering
Strain-Induced Disorder, Phase Transformations, And Transformation-Induced Plasticity In Hexagonal Boron Nitride Under Compression And Shear In A Rotational Diamond Anvil Cell: In Situ X-Ray Diffraction Study And Modeling, Valery I. Levitas, Yanzhang Ma, Javad Hashemi, Mark Holtz, Necip Guven
Strain-Induced Disorder, Phase Transformations, And Transformation-Induced Plasticity In Hexagonal Boron Nitride Under Compression And Shear In A Rotational Diamond Anvil Cell: In Situ X-Ray Diffraction Study And Modeling, Valery I. Levitas, Yanzhang Ma, Javad Hashemi, Mark Holtz, Necip Guven
Valery I. Levitas
Plastic shear significantly reduces the phase transformation (PT) pressure when compared to hydrostatic conditions. Here, a paradoxical result was obtained: PT of graphitelike hexagonal boron nitride (hBN) to superhard wurtzitic boron nitride under pressure and shear started at about the same pressure(∼10GPa) as under hydrostatic conditions. In situ x-ray diffraction measurement and modeling of the turbostratic stacking fault concentration (degree of disorder) and PT in hBN were performed. Under hydrostaticpressure, changes in the disorder were negligible. Under a complex compression and shear loading program, a strain-induced disorder was observed and quantitatively characterized. It is found that the strain-induced disorder suppresses …
Topography-Induced Contributions To Friction Forces Measured Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan
Topography-Induced Contributions To Friction Forces Measured Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan
Sriram Sundararajan
Most friction studies using an atomic force/friction force microscope, while concentrating on material-induced effects, often present users with conflicting and confusing interpretations of the topography-induced friction forces. It has been generally reported that topography-induced contributions are independent of scanning direction and can be removed by subtracting friction data from forward and backward scans. In this article, we present friction studies on samples with well-defined topography variations and find that the above-given statement is not generally true. At surface locations involving significant changes in topography, the topography-induced contributions to friction forces are found to be different between forward and backward scanning …
Sensors For Site-Specific Management, Stuart J. Birrell, J. W. Hummel, K. A. Sudduth
Sensors For Site-Specific Management, Stuart J. Birrell, J. W. Hummel, K. A. Sudduth
Stuart J. Birrell
Site-specific management (SSM, also known as precision farming, precision agriculture, prescription farming, etc.) is a management strategy that seeks to address within-field variability and to optimize inputs such as pesticides and fertilizers on a point-by-point basis within a field. By reducing over-application and under-application of nutrients and pesticides, this strategy has the potential to improve profitability for the producer and also to reduce the threat of groundwater or surface water contamination from agrichemicals. SSM is being adopted by innovative producers across the country. Agricultural equipment manufacturers, farm input suppliers, and a host of other businesses are working along with publicsector …
Nutrient Mapping Implications Of Short-Range Variability, Stuart J. Birrell
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
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.
Comparison Of Variable Rate To Single Rate Nitrogen Fertilizer Application: Corn Production And Residual Soil No3-N, N. R. Kitchen, D. F. Hughes, K. A. Sudduth, Stuart J. Birrell
Comparison Of Variable Rate To Single Rate Nitrogen Fertilizer Application: Corn Production And Residual Soil No3-N, N. R. Kitchen, D. F. Hughes, K. A. Sudduth, Stuart J. Birrell
Stuart J. Birrell
The questions most often asked by farmers when discussing variable rate (VR) fertilizer inputs are "How much will it cost?" and "How will it affect my yields?" Many farmers and custom application services share a reluctance to invest in the time and technology required for variable fertilizer application since studies to answer these questions are few and results have been inconsistent.