scholarly journals Correction of collimator-dependent differences in the heart-to-mediastinum ratio in 123I-metaiodobenzylguanidine cardiac sympathetic imaging: Determination of conversion equations using point-source imaging

2016 ◽  
Vol 24 (5) ◽  
pp. 1725-1736 ◽  
Author(s):  
Yusuke Inoue ◽  
Yutaka Abe ◽  
Kei Kikuchi ◽  
Keiji Matsunaga ◽  
Ray Masuda ◽  
...  
Keyword(s):  
Point Source ◽  
Source Imaging ◽  
Heart To Mediastinum Ratio ◽  
Sympathetic Imaging

Determination of point source mechanisms

2014 ◽  
pp. 108-134 ◽  
Author(s):  
Agustin Udias ◽  
Raul Madariaga ◽  
Elisa Buforn
Keyword(s):  
Point Source ◽  
Source Mechanisms

scholarly journals Image Reconstruction from VLBI Amplitude and Phase Closure Data

1979 ◽  
Vol 49 ◽  
pp. 93-93
Author(s):  
William D. Cotton ◽  
Jill J. Wittels
Keyword(s):  
Point Source ◽  
Direct Synthesis ◽  
Angular Structure ◽  
Long Baseline ◽  
Test Models ◽  
Step Procedure ◽  
Source Convergence ◽  
Using Data ◽  
Starting Model

AbstractA two step procedure is developed for the determination of the angular structure of the compact components of radio sources from observations made with very long baseline interferometry (VLBI). The first step is to fit a model composed of circularly symmetric Gaussian components to the observations. Then this, or any other, model and closure phase information is used to predict visibility phases which, when paired with the corresponding visibility amplitude observation, are combined in a direct synthesis; the resulting map is deconvolved from the point source response by means of the “CLEAN” procedure. If necessary, the “cleaned” components can be used as a starting model to predict visibility phases and the process iterated. The initial model in many cases may be as simple as a point source. Convergence of this process appears to be quite rapid, requiring only a few iterations when the source is simple or the starting model is good. These two steps for source mapping can be used either together or separately. Examples are given using data generated from test models.

scholarly journals Modelling the thermal radiation from kitchen hob fires

2020 ◽  
Vol 38 (4) ◽  
pp. 377-394
Author(s):  
Michael Spearpoint ◽  
Charlie Hopkin ◽  
Danny Hopkin
Keyword(s):  
Heat Flux ◽  
Point Source ◽  
Radial Distance ◽  
Source Model ◽  
View Factor ◽  
Calculation Methods ◽  
Fire Dynamics ◽  
Potential Threat ◽  
Computational Tools

Kitchen hob fires present a potential threat to occupants escaping from dwellings and calculations may be needed to assess the hazard. Determination of the thermal heat flux from flames to a target can be achieved through the use of hand calculation methods or computational tools. This article compares point source, parallel plane and cylindrical view factor hand calculations and computational simulations using B-RISK and Fire Dynamics Simulator of thermal heat flux with kitchen hob fire experiments presented in the literature. Knowing the level of accuracy of each method provides useful information to designers. Although the point source model is influenced by whether the radial distance is measured perpendicular to the heat flux target or is offset relative to the centre of the flame, the article concludes that it provides an adequate approach for the calculation of thermal heat flux in the case of kitchen hob fires.

Determination of Less-Than-Lifetime Exposures to Point Source Emissions

Risk Analysis ◽  
1992 ◽  
Vol 12 (3) ◽  
pp. 367-382 ◽  
Author(s):  
Paul S. Price ◽  
James Sample ◽  
Robert Strieter
Keyword(s):  
Point Source
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