Demagnetization Experience in Shipbuilding. Application to Different Industries

NDT World ◽  
2015 ◽  
Vol 18 (3) ◽  
pp. 21-24
Author(s):  
Сорокина ◽  
Nataliya Sorokina ◽  
Закомолдин ◽  
Igor Zakomoldin ◽  
Богачева ◽  
...  

The article proves the necessity for a demagnetization process in mechanical engineering, nondestructive testing, welding. Analysis of demagnetization methods of offshore facilities in shipbuilding, proven experimentally, gives examples of their effective use in other areas of technology. The article gives in general terms a theoretical basis of demagnetization and highlights the need to achieve a stable demagnetized state for large-scale structures. Taking into account the demagnetization experience in shipbuilding, the authors offer a simplified version of a stationary stand designed to reduce a level of products’ residual magnetization. It is shown that the use of demagnetization in various fields of technology has the prospect of improving the quality and efficiency of industrial equipment.

Author(s):  
J B Edwards

Simplified models of piecewise rigid support structures for power-loaders operating on longwall coal-faces are shown to be amenable to analysis by z-transform methods. Such analysis predicts that increasing sufficiently the length of the sub-sections of the structure (compared to the inherent delay within the vertical steering system of the machine) should stabilize the vertical steering of the entire coalface. Increasing the width of the structure to embrace more than two consecutive cut floors is shown analytically to eliminate the need for electronic tilt-feedback in control systems. In general terms, these analytical predictions are shown to hold good in detailed simulations of the system that eliminate the simplifications demanded by the analytical method. The general conclusion of the work is therefore that an increase in the size of support structure segments can potentially reduce the complexity of steering control systems. The size-increase must be substantial, e.g. to four to five times the size of conventional structures.


1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.


2015 ◽  
Vol 12 (108) ◽  
pp. 20150044 ◽  
Author(s):  
Dervis C. Vural ◽  
Alexander Isakov ◽  
L. Mahadevan

Starting with Darwin, biologists have asked how populations evolve from a low fitness state that is evolutionarily stable to a high fitness state that is not. Specifically of interest is the emergence of cooperation and multicellularity where the fitness of individuals often appears in conflict with that of the population. Theories of social evolution and evolutionary game theory have produced a number of fruitful results employing two-state two-body frameworks. In this study, we depart from this tradition and instead consider a multi-player, multi-state evolutionary game, in which the fitness of an agent is determined by its relationship to an arbitrary number of other agents. We show that populations organize themselves in one of four distinct phases of interdependence depending on one parameter, selection strength. Some of these phases involve the formation of specialized large-scale structures. We then describe how the evolution of independence can be manipulated through various external perturbations.


2011 ◽  
Vol 418 (1) ◽  
pp. 214-229 ◽  
Author(s):  
Marco Baldi ◽  
Valeria Pettorino ◽  
Luca Amendola ◽  
Christof Wetterich

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