Feynman-parameter representation of old-fashioned perturbation diagrams

1969 ◽  
Vol 59 (4) ◽  
pp. 435-443
Author(s):  
C. S. Lam
1973 ◽  
Vol 16 (1) ◽  
pp. 149-157 ◽  
Author(s):  
T.R. Ananthakrishnan ◽  
C.P. Girijavallabhan ◽  
G. Aruldhas

2008 ◽  
Vol 8 (20) ◽  
pp. 6273-6279 ◽  
Author(s):  
M. D. Petters ◽  
S. M. Kreidenweis

Abstract. The ability of a particle to serve as a cloud condensation nucleus in the atmosphere is determined by its size, hygroscopicity and its solubility in water. Usually size and hygroscopicity alone are sufficient to predict CCN activity. Single parameter representations for hygroscopicity have been shown to successfully model complex, multicomponent particles types. Under the assumption of either complete solubility, or complete insolubility of a component, it is not necessary to explicitly include that component's solubility into the single parameter framework. This is not the case if sparingly soluble materials are present. In this work we explicitly account for solubility by modifying the single parameter equations. We demonstrate that sensitivity to the actual value of solubility emerges only in the regime of 2×10−1–5×10−4, where the solubility values are expressed as volume of solute per unit volume of water present in a saturated solution. Compounds that do not fall inside this sparingly soluble envelope can be adequately modeled assuming they are either infinitely soluble in water or completely insoluble.


2017 ◽  
Vol 20 (11) ◽  
pp. 1623-1631 ◽  
Author(s):  
Patrick Salcher ◽  
Christoph Adam

The objective of this study is to provide the engineering practice with a tool for simplified dynamic response assessment of high-speed railway bridges in the pre-design phase. To serve this purpose, a non-dimensional representation of the characteristic parameters of the train–bridge interaction problem is described and extended based on a beam bridge model subjected to the static axle loads of the crossing high-speed train. The non-dimensional parameter representation is used to discuss several code-related design issues. It is revealed that in an admitted parameter domain, a code-regulated static assessment of high-speed railway bridges may under-predict the actual dynamic response. Furthermore, the minimum mass of a bridge as a function of the characteristic parameters is presented to comply with the maximum bridge acceleration specified in standards.


1976 ◽  
Vol 61 (2) ◽  
pp. 177-183 ◽  
Author(s):  
C.P. Girijavallabhan ◽  
S. Sasidharan Nair ◽  
K. Babu Joseph

1974 ◽  
Vol 29 (6) ◽  
pp. 916-923
Author(s):  
W. Bauhoff

The Fredholm approximation is discussed in the framework of the scalar Bethe-Salpeter equation. The trace of the angular momentum decomposed kernel is expressed in terms of Feynman parameter integrals which shows the relation to the vertex function. A new derivation for this representation is given which is far more direct than the previous one. Using this representation, several general features of the eigenvalues are discussed. For special cases, the trace is computed explicitly, and the numerical values are compared with the exact ones, obtained by variational methods.


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