The simulation of structural and thermal systems via flow graphs

SIMULATION ◽  
1967 ◽  
Vol 9 (3) ◽  
pp. 149-156
Author(s):  
Larry J. Feeser ◽  
Chuan C. Feng
Keyword(s):  
Heat Flow ◽  
Oriented Graph ◽  
Initial Boundary ◽  
The Other ◽  
Mesh Network ◽  
Graph Representation ◽  
Structural Systems ◽  
Central Difference ◽  
Physical Systems ◽  
Flow Graphs

This paper presents a study of simulation of structural systems and heat flow problems by use of oriented flow graphs. Linear elastic structural systems are transformed into graph representation using two kinds of parametric analyses. In one case, flexibility parameters of structural components are used as branch transmittances of the or iented graphs, and geometric displacements are the ex ternal sources or inputs to the graph. In the other ap proach, stiffness coefficients as graph transmittances and unbalanced residual loads as source inputs lead to relax ation operations which can be represented by feedback analysis. Each of these approaches is the dual of the other in a topological sense. Two-dimensional problems governed by the Laplacian partial differential equation are solved by using first-order central difference analysis to transform the governing equation into an oriented graph. The graph networks of physical systems of this type can be constructed by in spection of the mesh network without recourse to the difference equations. Initial boundary values are treated as independent source inputs to the graph. A solution of the steady-state heat flow in a thin plate is presented. The simulation of physical systems by oriented flow graphs treats the system as an entity in which the physical characteristics are transformed topologically into graph representations. Oriented graphs are essentially analog setups from which numerical results can be obtained by analog computers. If use is made of the loop-rule equa tions of graph theory, efficient use of the digital computer is indicated. The nature of design of structural systems is complex because of the range of parameters to be con sidered and because of required accuracy. Flow graph simulation can give information on the effect of variation of parameters by way of sensitivity analysis and can be an aid in the study of design.

Part 2. The deeper structure of the Atlantic - Geological hypotheses and the earth's crust under the oceans

1954 ◽  
Vol 222 (1150) ◽  
pp. 341-348 ◽  
Keyword(s):  
Heat Flow ◽  
Recent Work ◽  
Sea Water ◽  
Volcanic Rocks ◽  
The Other ◽  
Ocean Floor ◽  
Peridotite Xenoliths ◽  
The Earth ◽  
Southern Rhodesia ◽  
Mohorovičić Discontinuity

Recent work has determined the depth of the Mohorovičić discontinuity at sea and has made it likely that peridotite xenoliths in basaltic volcanic rocks are samples of material from below the discontinuity. It is now possible to produce a hypothetical section showing the transition from a continent to an ocean. This section is consistent with both the seismic and gravity results. The possible reactions of the crust to changes in the total volume of sea water are dis­cussed. It seems possible that the oceans were shallower and the crust thinner in the Archean than they are now. If this were so, some features of the oldest rocks of Canada and Southern Rhodesia could be explained. Three processes are described that might lead to the formation of oceanic ridges; one of these involves tension, one compression and the other quiet tectonic conditions. It is likely that not all ridges are formed in the same way. It is possible that serpentization of olivine by water rising from the interior of the earth plays an important part in producing changes of level in the ocean floor and anomalies in heat flow. Finally, a method of reducing gravity observations at sea is discussed.

Temperature, strain rates, and rheology: the key parameters controling strength variations in the Australian lithosphere

2020 ◽  
Author(s):  
Magdala Tesauro ◽  
Mikhail Kaban ◽  
Alexey Petrunin ◽  
Alan Aitken
Keyword(s):  
Heat Flow ◽  
Seismic Tomography ◽  
Seismic Velocity ◽  
Gravity Data ◽  
Geophysical Methods ◽  
The Other ◽  
Crust And Upper Mantle ◽  
Large Variability ◽  
Other Hand ◽  
Australian Plate

<p>The Australian plate is composed of tectonic features showing progression of the age from dominantly Phanerozoic in the east, Proterozoic in the centre, and Archean in the west. These tectonic structures have been investigated in the last three decades using a variety of geophysical methods, but it is still a matter of debates of how temperature and strength are distributed within the lithosphere. We construct a thermal crustal model assuming steady state variations and using surface heat flow data, provided by regional and global database, and heat generation values, calculated from existing empirical relations with seismic velocity variations, which are provided by AusREM seismic tomography model. The lowest crustal temperatures are observed in the eastern part of the WAC and the Officer basin, while Central and South Australia are regions with anomalously elevated heat flow values and temperatures caused by high heat production in the crustal rocks. On the other hand, the mantle temperatures, estimated in a previous study, applying a joint interpretation of the seismic tomography and gravity data, show that the Precambrian West and North Australian Craton (WAC and NAC) are characterized by thick and relatively cold lithosphere that has depleted composition (Mg# > 90). The depletion is stronger in the older WAC than the younger NAC. Substantially hotter and less dense lithosphere is seen fringing the eastern and southeastern margin of the continent. Both crustal and mantle thermal models are used as input for the lithospheric strength calculation. Another input parameter is the crustal rheology, which has been determined based on the seismic velocity distribution, assuming that low (high) velocities reflect more sialic (mafic) compositions and thus weaker (stiffer) rheologies. Furthermore, we use strain rate values obtained from a global mantle flow model constrained by seismic and gravity data. The combination of the values of the different parameters produce a large variability of the rigidity of the plate within the cratonic areas, reflecting the long tectonic history of the Australian plate. The sharp lateral strength variations are coincident with intraplate earthquakes location. The strength variations in the crust and upper mantle is also not uniformly distributed: In the Archean WAC most of the strength is concentrated in the mantle, while the Proterozoic Officer basin shows the largest values of the crustal strength. On the other hand, the younger eastern terranes are uniformly weak, due to the high temperatures.</p>

scholarly journals On Some Problems Generated by a Sesquilinear Form

2017 ◽  
Vol 63 (2) ◽  
pp. 278-315
Author(s):  
N D Kopachevskii ◽  
A R Yakubova
Keyword(s):  
Boundary Value Problems ◽  
Laplace Operator ◽  
Initial Boundary ◽  
The Other ◽  
Green Formula ◽  
Initial Boundary Value Problems ◽  
Dissipation Of Energy ◽  
Sesquilinear Form ◽  
Initial Boundary Value ◽  
The Laplace Operator

Based on the generalized Green formula for a sesquilinear nonsymmetric form for the Laplace operator, we consider spectral nonself-adjoint problems. Some of them are similar to classical problems while the other arise in problems of hydrodynamics, diffraction, and problems with surface dissipation of energy. Properties of solutions of such problems are considered. Also we study initial-boundary value problems generating considered spectral problems and prove theorems on correct solvability of such problems on any interval of time.

scholarly journals The Cosmological Decrease of Galactic Density and the Induced Retarded Gravity Effect on Rotation Curves

2021 ◽  
Author(s):  
Asher Yahalom
Keyword(s):  
Dark Matter ◽  
Galactic Center ◽  
Temporal Change ◽  
The Other ◽  
Local Effects ◽  
Physical Systems ◽  
Cosmic Expansion ◽  
The Galaxy ◽  
Action At A Distance ◽  
Retardation Effects

Galaxies are huge physical systems having dimensions of many tens of thousands of light years. Thus any change at the galactic center will be noticed at the rim only tens of thousands of years later. Those retardation effects seems to be neglected in present day galactic modelling used to calculate rotational velocities of matter in the rims of the galaxy and surrounding gas. The significant differences between the predictions of Newtonian instantaneous action at a distance and observed velocities are usually explained by either assuming dark matter or by modifying the laws of gravity (MOND). In this paper we will show that taking general relativity seriously without neglecting retardation effects one can explain the radial velocities of galactic matter without postulating dark matter. However, this will rely on a temporal change of galactic mass. We will compare two different mechanisms of density change, one is local, that is accretion of matter from the intergalactic medium. The other is global, that is the cosmological decrease of density due to the cosmic expansion. It will be shown that local effects are much more important in this respect.

scholarly journals Entropy, the Information Processing Cycle, and the Forecasting of Bull and Bear Market Peaks and Troughs

2019 ◽  
Vol 7 (1) ◽  
pp. 77-90
Author(s):  
Edgar Parker
Keyword(s):  
Information Processing ◽  
Yield Curve ◽  
The Other ◽  
Financial Systems ◽  
Information Theoretic ◽  
Physical Systems ◽  
Bear Market ◽  
Human Interactions ◽  
Financial Cycles ◽  
Processing Cycle

Many econophysics applications have modeled financial systems as if they were pure physical systems devoid of human limitations and errors. On the other hand, traditional financial theory has ignored limits that physics would impose on human interactions, communications, and computational abilities. The entropic yield curve blends the physical and human financial worlds in a new, powerful, and surprisingly simple way. This article uses this information theoretic perspective to provide a new explanation of the dynamics and timing of financial cycles. Additionally, the entropic yield curve offers a new method of forecasting market peaks and troughs.

Uniqueness theorem for Inverse Sturm–Liouville Problem with Nonseparated Boundary Conditions

2016 ◽  
Vol 11 (2) ◽  
pp. 167-170
Author(s):  
A.M. Akhtyamov ◽  
Kh.R. Mamedov
Keyword(s):  
Boundary Value Problem ◽  
Boundary Conditions ◽  
Frequency Spectrum ◽  
Natural Frequencies ◽  
Boundary Value ◽  
Initial Boundary ◽  
The Other ◽  
Elasticity Coefficient ◽  
Nonseparated Boundary Conditions ◽  
String Vibrations

Consider the string, which vibrates in a medium with the variable elasticity coefficient q(x). Interesting to follow the inverse problem: is it possible to determine the variable elasticity coefficient q(x) by the natural frequencies of string vibrations. In 1946, G. Borg has been shown that a spectrum of frequencies is not sufficient to uniquely identify the medium elasticity coefficient q(x). He offered the use of two frequency spectrum to uniquely identify of the medium elasticity coefficient q(x). The second frequency spectrum is obtained by fastening the string to change at one of its ends to the other fastening. It was shown that these two frequency spectra already sufficient to uniquely identify q(x) and the boundary conditions of both problems. The case where the string fastening at one end depends on the other end fastening, is more difficult to solve. The boundary conditions, appropriate for the occasion, called nonseparated. Two spectra (of two boundary value problems) to restore both q(x), and the nonseparated boundary conditions are not enough. In modern studies the spectra of the two eigenvalues boundary problems and an infinite sequence of signs is generally used for an uniqueness recovery. While this approach is useful in theoretical mathematics, it is inconvenient for the mechanics, because not clear the physical meaning of the corresponding sequence of signs. In this article, instead of the two spectra and the sequence of signs as the spectral data are offered to use 7 of the eigenvalues of the initial boundary value problem, the spectrum, and the so-called norming constants of other boundary value problem. The physical sense of these data is quite clear. The first 7 eigenvalues of an initial boundary problem mean the first 7 natural frequencies of string vibrations. Norming constants represent norms from eigenfunctions. The spectrum and norming constants express a so-called spectral function. The spectral function gives a frequency spectrum with columns of vibrations amplitudes characteristics for string vibrations with other types of fastening.

Local fluid and heat flow near contact lines

1998 ◽  
Vol 371 ◽  
pp. 377-378
Author(s):  
D. M. Anderson ◽  
S. H. Davis
Keyword(s):  
Boundary Condition ◽  
Free Surface ◽  
Heat Flow ◽  
Fluid Mechanics ◽  
Contact Line ◽  
Thermal Boundary Condition ◽  
The Other ◽  
Private Communication ◽  
Contact Lines ◽  
Rigid Plane

Journal of Fluid Mechanics, vol. 268 (1994), pp. 231–265It has recently come to our attention that our paper, which describes Marangoni-driven flow near a contact line, overlooks solutions involving a general thermal boundary condition on the free surface (private communication, S. J. Tavener 1997). These new solutions are applicable for non-isothermal flows in a corner region where one boundary is a rigid plane (and either perfectly insulating or perfectly conducting) and the other is a free surface upon which a general thermal boundary condition is applied. We describe these additional solutions below.

N-BODY CLASSICAL SYSTEMS AND NEURAL NETWORKS ON A 3D SIMD MASSIVE PARALLEL PROCESSOR: APE100/QUADRICS

1995 ◽  
Vol 06 (02) ◽  
pp. 169-182 ◽  
Author(s):  
P.S. PAOLUCCI
Keyword(s):  
Neural Networks ◽  
Parallel Architecture ◽  
The Other ◽  
Parallel Processor ◽  
Physical Systems ◽  
Classical Systems ◽  
Lennard Jones ◽  
Interaction Terms ◽  
Processing Power ◽  
Communication Path

A number of physical systems (e.g., N body Newtonian, Coulombian or Lennard-Jones systems) can be described by N2 interaction terms. Completely connected neural networks are characterised by the same kind of connections: Each neuron sends signals to all the other neurons via synapses. The APE100/Quadricsmassive parallel architecture, with processing power in excess of 100 Gigaflops and a central memory of 8 Gigabytes seems to have processing power and memory adequate to simulate systems formed by more than 1 billion synapses or interaction terms. On the other hand the processing nodes of APE100/Quadrics are organised in a tridimensional cubic lattice; each processing node has a direct communication path only toward the first neighboring nodes. Here we describe a convenient way to map systems with global connectivity onto the first-neighbors connectivity of the APE100/Quadrics architecture. Some numeric criteria, which are useful for matching SIMD tridimensional architectures with globally connected simulations, are introduced.

The world-wide oceanic rise-ridge system

1965 ◽  
Vol 258 (1088) ◽  
pp. 109-122 ◽  
Keyword(s):  
Heat Flow ◽  
World Wide ◽  
High Heat ◽  
The Other ◽  
Normal Faults ◽  
Normal Faulting ◽  
High Heat Flow ◽  
Flood Basalts ◽  
The World ◽  
Ridge System

About half the length of the * oceanic ’ rise-ridge system is centred in ocean basins. On the other hand, almost the whole system is approximately disposed in circles around continental shields. Exceptional heating of the system is indicated by high heat flow and the extrusion of extraordinary volumes of flood basalts. The concentration of volcanoes, however, is little greater than normal for ocean basins. Longitudinal normal faulting and transverse wrench faulting are characteristic of the system. Both types formed early in the life of the system and are still active. Wrench faults offset belts of normal faulting and the crests of rises and ridges in many places but are not themselves known to be offset by normal faults. The ancient Darwin Rise has subsided in the southwestern Pacific. Its history differs in some respects from other rises although it too was heated and faulted. A hypothesis of origin of the system is briefly discussed.

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