1,617 research outputs found
Numerical solution of two dimensional harmonic boundary problems containing singularities by conformal transformation methods
Numerical solutions to a class of two dimensional harmonic mixed boundary value problems defined on rectangular domains and containing singularities are obtained using conformal transformation methods. These map the original problems into similar ones containing no singularities, and to which analytic solutions are known. Although the mapping technique produces analytic solutions to the original problems, these involve elliptic functions and integrals which have to be evaluated numerically, so that in practice only approximations can be obtained. Results calculated in this manner for model problems compare favourably with those obtained previously by other methods. On this evidence, and because of the ease with which the method can be adapted to different individual problems, we strongly recommend the transformation technique for solving problems of this class.
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A numerical conformal transformation method for harmonic mixed boundary value problems in polygonal domains
A method is given for solving two dimensional
harmonic mixed boundary value problems in simply-connected polygonal domains with re-entrant boundaries. The method consists of a numerical conformal mapping together with three other conformal transformations. The numerical mapping transforms the original domain onto the unit circle,
which in turn is mapped onto a rectangle by means of two bilinear and one Schwarz-Christoffel transformations. The transformed problem in the rectangle is solved by inspection
Cubic spline interpolation of harmonic functions
It is shown that for the two dimensional Laplace equation a univariate cubic spline approximation in either space direction together with a difference approximation in the other leads to the well-known nine-point finite-difference formula.
For harmonic problems defined in rectangular regions this property provides a means of determining with ease accurate approximations at any point in the region
A cubic spline technique for the one dimensional heat conduction equation
A new method is developed for the numerical solution of the heat conduction equation in one space dimension by replacing the space derivative with a cubic spline approximation and the time derivative with a finite- difference approximation. The method is equivalent to a new finite-difference scheme and produces at each time level an interpolating spline function
The Role of Narrative Fiction and Semi-Fiction in Organizational Studies
In this chapter, we discuss the use of narrative fiction and semi-fiction in organizational research and explore the strengths and weaknesses of these alternative approaches. We begin with an introduction reviewing the existing literature and clarifying what we mean by fiction and semi-fiction. We then present and discuss examples of fiction and semi-fiction focusing on how these approaches can be used in organizational research. We argue that fiction is more useful as a source of data and as a way of representing theory to an audience. Semi-fiction, on the other hand, provides a novel approach to the production and representation of theory. In both cases, researchers face a number of challenges, but also gain access to new and powerful techniques for developing insights into organizational topics.Organizational studies;Narrative fiction;Semi-fiction
The Role of Narrative Fiction and Semi-Fiction in Organizational Studies
In this chapter, we discuss the use of narrative fiction and semi-fiction in organizational research and explore the strengths and weaknesses of these alternative approaches. We begin with an introduction reviewing the existing literature and clarifying what we mean by fiction and semi-fiction. We then present and discuss examples of fiction and semi-fiction focusing on how these approaches can be used in organizational research. We argue that fiction is more useful as a source of data and as a way of representing theory to an audience. Semi-fiction, on the other hand, provides a novel approach to the production and representation of theory. In both cases, researchers face a number of challenges, but also gain access to new and powerful techniques for developing insights into organizational topics
ALVICE Lidar Results from the MOHAVE 2009 Field Campaign
The NASA/GSFC Atmospheric Lidar for Validation/Interagency Collaboration and Education (ALVICE) participated in the Measurements of Humidity And Validation Experiments (MOHAVE 209) campaign hosted at the JPL/Table Mountain Facility in Southern California. This field campaign brought together a large number of water vapor measuring instruments in an effort to inter-compare and validate numerous water vapor technologies in use within the Network for the Detection of Atmospheric Composition Change (NDACC). A central focus of the campaign was to perform validation of Raman lidar systems in use within NDACC. ALVICE is one of the mobile intercomparison lidar instruments within NDACC and MOHAVE provided an excellent opportunity to test and validate the measurements of this system. At the workshop, we will present recent analysis results of ALVICE lidar measurements and put them in the context of the full field campaign
Comments on: Accuracy of Raman Lidar Water Vapor Calibration and its Applicability to Long-Term Measurements
In a recent publication, LeBlanc and McDermid proposed a hybrid calibration technique for Raman water vapor lidar involving a tungsten lamp and radiosondes. Measurements made with the lidar telescope viewing the calibration lamp were used to stabilize the lidar calibration determined by comparison with radiosonde. The technique provided a significantly more stable calibration constant than radiosondes used alone. The technique involves the use of a calibration lamp in a fixed position in front of the lidar receiver aperture. We examine this configuration and find that such a configuration likely does not properly sample the full lidar system optical efficiency. While the technique is a useful addition to the use of radiosondes alone for lidar calibration, it is important to understand the scenarios under which it will not provide an accurate quantification of system optical efficiency changes. We offer examples of these scenarios
Performance modeling of ultraviolet Raman lidar systems for daytime profiling of atmospheric water vapor
We describe preliminary results from a comprehensive computer model developed to guide optimization of a Raman lidar system for measuring daytime profiles of atmospheric water vapor, emphasizing an ultraviolet, solar-blind approach
The METCRAX II Field Experiment: A Study of Downslope Windstorm-Type Flows in Arizona\u2019s Meteor Crater
The second Meteor Crater Experiment (METCRAX II) was conducted in October 2013 at Arizona\u2019s Meteor Crater. The experiment was designed to investigate nighttime downslope windstorm 12type flows that form regularly above the inner southwest sidewall of the 1.2-km diameter crater as a southwesterly mesoscale katabatic flow cascades over the crater rim. The objective of METCRAX II is to determine the causes of these strong, intermittent, and turbulent inflows that bring warm-air intrusions into the southwest part of the crater. This article provides an overview of the scientific goals of the experiment; summarizes the measurements, the crater topography, and the synoptic meteorology of the study period; and presents initial analysis results
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