scholarly journals Extending the Transport Theorem to Rough Domains of Integration

2014 ◽  
Vol 66 (5) ◽  
Author(s):  
Brian Seguin ◽  
Denis F. Hinz ◽  
Eliot Fried

Transport theorems, such as that named after Reynolds, are an important tool in the field of continuum physics. Recently, Seguin and Fried used Harrison's theory of differential chains to establish a transport theorem valid for evolving domains that may become irregular. Evolving irregular domains occur in many different physical settings, such as phase transitions or fracture. Here, emphasizing concepts over technicalities, we present Harrison's theory of differential chains and the results of Seguin and Fried in a way meant to be accessible to researchers in continuum physics. We also show how the transport theorem applies to three concrete examples and approximate the resulting terms numerically. Furthermore, we discuss how the transport theorem might be used to weaken certain basic assumptions underlying the description of continua and the challenges associated with doing so.

1993 ◽  
Vol 08 (15) ◽  
pp. 1443-1450 ◽  
Author(s):  
SERGE RUDAZ ◽  
AJIT MOHAN SRIVASTAVA

We examine the basic assumptions underlying a scenario due to Kibble that is widely used to estimate the production of topological defects. We argue that one of the crucial assumptions, namely the geodesic rule, although completely valid for global defects, becomes ill-defined for the case of gauged defects. We address the issues involved in formulating a suitable geodesic rule for this case and argue that the dynamics plays an important role in the production of gauge defects.


2014 ◽  
Vol 24 (09) ◽  
pp. 1729-1779 ◽  
Author(s):  
Brian Seguin ◽  
Eliot Fried

Well-known examples of transport theorems include the Leibniz integral rule and a result established by Reynolds for three-dimensional regions that convect with the motion of a continuum. Here, we prove a generalized transport theorem by relaxing the regularity assumptions on the domain of integration to include domains that may, among other things, develop holes, split into pieces, or whose fractal dimension may evolve with time. Our results are of potential value in continuum physics and the calculus of variations.


Author(s):  
G. Timp ◽  
L. Salamanca-Riba ◽  
L.W. Hobbs ◽  
G. Dresselhaus ◽  
M.S. Dresselhaus

Electron microscopy can be used to study structures and phase transitions occurring in graphite intercalations compounds. The fundamental symmetry in graphite intercalation compounds is the staging periodicity whereby each intercalate layer is separated by n graphite layers, n denoting the stage index. The currently accepted model for intercalation proposed by Herold and Daumas assumes that the sample contains equal amounts of intercalant between any two graphite layers and staged regions are confined to domains. Specifically, in a stage 2 compound, the Herold-Daumas domain wall model predicts a pleated lattice plane structure.


Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)


Author(s):  
Rohan Abeyaratne ◽  
James K. Knowles
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Author(s):  
Lorenza Saitta ◽  
Attilio Giordana ◽  
Antoine Cornuejols

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