Theory of Edge Diffraction in Electromagnetics: Origination and validation of the physical theory of diffraction

2009 ◽  
Author(s):  
Ufimtsev
Keyword(s):  
Physical Theory ◽  
Edge Diffraction

The Event Universe

2015 ◽  
Author(s):  
Leemon B. McHenry
Keyword(s):  
Electromagnetic Field ◽  
Quantum Mechanics ◽  
Common Sense ◽  
Physical Theory ◽  
Alfred North Whitehead ◽  
Bertrand Russell ◽  
Theory Of Relativity ◽  
The World ◽  
Modern Physics ◽  
Linguistic Methods

What kinds of things are events? Battles, explosions, accidents, crashes, rock concerts would be typical examples of events and these would be reinforced in the way we speak about the world. Events or actions function linguistically as verbs and adverbs. Philosophers following Aristotle have claimed that events are dependent on substances such as physical objects and persons. But with the advances of modern physics, some philosophers and physicists have argued that events are the basic entities of reality and what we perceive as physical bodies are just very long events spread out in space-time. In other words, everything turns out to be events. This view, no doubt, radically revises our ordinary common sense view of reality, but as our event theorists argue common sense is out of touch with advancing science. In The Event Universe: The Revisionary Metaphysics of Alfred North Whitehead, Leemon McHenry argues that Whitehead's metaphysics provides a more adequate basis for achieving a unification of physical theory than a traditional substance metaphysics. He investigates the influence of Maxwell's electromagnetic field, Einstein's theory of relativity and quantum mechanics on the development of the ontology of events and compares Whitehead’s theory to his contemporaries, C. D. Broad and Bertrand Russell, as well as another key proponent of this theory, W. V. Quine. In this manner, McHenry defends the naturalized and speculative approach to metaphysics as opposed to analytical and linguistic methods that arose in the 20th century.

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays

2011 ◽  
Vol 57 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Mariusz Zamłyński ◽  
Piotr Słobodzian
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Planar Antenna ◽  
Sidelobe Level ◽  
Edge Diffraction ◽  
Narrow Angle ◽  
Compensation Technique ◽  
Diffraction Effects ◽  
Linear Antenna Arrays

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays In this paper the quality of a technique to compensate for mutual coupling (and other phenomena) in small linear antenna arrays is investigated. The technique consists in calculation of a coupling matrix, which is than used to determine corrected antenna array excitation coefficients. Although the technique is known for more than 20 years, there is still very little information about how different phenomena existing in a real antenna arrays influence its performance. In this paper two models of antenna arrays are used. In the first model the effect of mutual coupling is separated from the aperture edge diffraction. In the second model antenna both mutual coupling and aperture edge diffraction effects are included. It is shown that mutual coupling itself can be compensated very well and an ultralow sidelobe level (i.e. -50 dB) could be achieved in practice. In the presence of diffraction effects -46.3 dB sidelobe level has been attained, but radiation pattern can be controled only in narrow angle range (i.e. up to ±60°).

Incorporating concepts from physical theory into stochastic modelling of urban runoff pollution

1998 ◽  
Vol 37 (1) ◽  
pp. 179-185
Author(s):  
Morten Grum
Keyword(s):  
Stochastic Model ◽  
Continuous Time ◽  
Measurement Errors ◽  
Physical Theory ◽  
Oxygen Demand ◽  
Stochastic Modelling ◽  
Urban Runoff ◽  
Primary Input ◽  
Deterministic Modelling ◽  
Runoff Pollution

On evaluating the present or future state of integrated urban water systems, sewer drainage models, with rainfall as primary input, are often used to calculate the expected return periods of given detrimental acute pollution events and the uncertainty thereof. The model studied in the present paper incorporates notions of physical theory in a stochastic model of water level and particulate chemical oxygen demand (COD) at the overflow point of a Dutch combined sewer system. A stochastic model based on physical mechanisms has been formulated in continuous time. The extended Kalman filter has been used in conjunction with a maximum likelihood criteria and a non-linear state space formulation to decompose the error term into system noise terms and measurement errors. The bias generally obtained in deterministic modelling, by invariably and often inappropriately assuming all error to result from measurement inaccuracies, is thus avoided. Continuous time stochastic modelling incorporating physical, chemical and biological theory presents a possible modelling alternative. These preliminary results suggest that further work is needed in order to fully appreciate the method's potential and limitations in the field of urban runoff pollution modelling.

Entity and Aspects. (As Pertaining to Physical Theory)

1947 ◽  
Vol 14 (2) ◽  
pp. 105-115 ◽  
Author(s):  
Erwin Biser
Keyword(s):  
Physical Theory

Edge diffraction at a curved screen

1974 ◽  
Vol 10 (10) ◽  
pp. 167 ◽  
Author(s):  
G.L. James
Keyword(s):  
Edge Diffraction

scholarly journals Two Kindred Neo-Kantian Philosophies of Science: Pap’s The A Priori in Physical Theory and Cassirer’s Determinism and Indeterminism in Modern Physics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Thomas Mormann
Keyword(s):  
Philosophy Of Science ◽  
20Th Century ◽  
Physical Theory ◽  
A Priori ◽  
Logical Empiricism ◽  
Main Thesis ◽  
Modern Physics ◽  
Continental Tradition ◽  
Determinism And Indeterminism ◽  
Kantian Philosophy

Abstract The main thesis of this paper is that Pap’s The Functional A Priori in Physical Theory and Cassirer’s Determinism and Indeterminism in Modern Physics may be conceived as two kindred accounts of a late Neo-Kantian philosophy of science. They elucidate and clarify each other mutually by elaborating conceptual possibilities and pointing out affinities of neo-Kantian ideas with other currents of 20th century’s philosophy of science, namely, pragmatism, conventionalism, and logical empiricism. Taking into account these facts, it seems not too far fetched to conjecture that under more favorable circumstances Pap could have served as a mediator between the “analytic” and “continental” tradition thereby overcoming the dogmatic dualism of these two philosophical currents that has characterized philosophy in the second half the 20th century.

Generalized Riemann spaces

1956 ◽  
Vol 52 (4) ◽  
pp. 623-625 ◽  
Author(s):  
John Moffat
Keyword(s):  
Curvature Tensor ◽  
Physical Theory ◽  
Dimensional Space ◽  
Riemann Space ◽  
Recent Attempt ◽  
Fundamental Tensor ◽  
Fundamental Properties ◽  
Complex Symmetric ◽  
Definition Of ◽  
Generalized Curvature Tensor

ABSTRACTThe recent attempt at a physical interpretation of non-Riemannian spaces by Einstein (1, 2) has stimulated a study of these spaces (3–8). The usual definition of a non-Riemannian space is one of n dimensions with which is associated an asymmetric fundamental tensor, an asymmetric linear affine connexion and a generalized curvature tensor. We can also consider an n-dimensional space with which is associated a complex symmetric fundamental tensor, a complex symmetric affine connexion and a generalized curvature tensor based on these. Some aspects of this space can be compared with those of a Riemann space endowed with two metrics (9). In the following the fundamental properties of this non-Riemannian manifold will be developed, so that the relation between the geometry and physical theory may be studied.

Sign in / Sign up

Export Citation Format

Share Document