scholarly journals Assembling a Formula for Current Transferring by Using a Summary Graph and Transformation Graphs

2013 ◽  
Vol 64 (5) ◽  
pp. 334-336 ◽  
Author(s):  
Bohumil Brtník
Keyword(s):  
Current Transfer ◽  
Memory Cells ◽  
Current Mirror ◽  
Two Phase ◽  
Derived Relations ◽  
Phase Switching ◽  
Graph Method ◽  
The Matrix ◽  
Switched Current ◽  
Summary Graph

Abstract This paper deals with the symbolic solution of the switched current circuits. As is described, the full graph method of the solution can be used for finding relationships expressing current transfer, too. The summa MC-graph is constructed using two-graphs method in two-phase switching. By comparing the matrix form with results of the Mason’s formula are derived relations for current transfers in all phases. There are discussed various options described transistor memory cells - with loss and lossless transistors and normal transistor current mirror. Evaluation of the graph is simplified if we consider the lossless transistors or if the y21 -parameter of one transistor is alpha multiple of second ones.

Transition alpha structure in beta-isomorphous Nb-Hf alloys

1987 ◽  
Vol 45 ◽  
pp. 232-233
Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Miscibility Gap ◽  
Large Strains ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Diffuse Intensity ◽  
Metastable Form ◽  
The Matrix ◽  
Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

Using crystallographic symmetry in diffraction and contrast analysis

1989 ◽  
Vol 47 ◽  
pp. 504-505
Author(s):  
U. Dahmen ◽  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
High Symmetry ◽  
Two Phase ◽  
Tem Analysis ◽  
Crystallographic Symmetry ◽  
The Matrix ◽  
Contrast Analysis ◽  
Practical Tool ◽  
Convergent Beam ◽  
Beam Diffraction

Despite the increased use of convergent beam diffraction, symmetry concepts in their more general form are not commonly applied as a practical tool in electron microscopy. Crystal symmetry provides an abundance of information that can be used to facilitate and improve the TEM analysis of crystalline solids. This paper draws attention to some aspects of symmetry that can be put to practical use in the analysis of structures and morphologies of two-phase materials.It has been shown that the symmetry of the matrix that relates different variants of a precipitate can be used to determine the axis of needle- or lath-shaped precipitates or the habit plane of plate-shaped precipitates. By tilting to a special high symmetry orientation of the matrix and by measuring angles between symmetry-related variants of the precipitate it is possible to find their habit from a single micrograph.

Microstructure of Polycrystalline MgO Penetrated by a Silicate Liquid

1996 ◽  
Vol 2 (3) ◽  
pp. 113-128 ◽  
Author(s):  
Sundar Ramamurthy ◽  
Michael P. Mallamaci ◽  
Catherine M. Zimmerman ◽  
C. Barry Carter ◽  
Peter R. Duncombe ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Grain Growth ◽  
Glassy Phase ◽  
Silicate Liquid ◽  
Two Phase ◽  
The Matrix ◽  
Devitrification Process ◽  
Phase Mixture

Dense, polycrystalline MgO was infiltrated with monticellite (CaMgSiO4) liquid to study the penetration of liquid along the grain boundaries of MgO. Grain growth was found to be restricted with increasing amounts of liquid. The inter-granular regions were generally found to be comprised of a two-phase mixture: crystalline monticellite and a glassy phase rich in the impurities present in the starting MgO material. MgO grains act as seeding agents for the crystallization of monticellite. The location and composition of the glassy phase with respect to the MgO grains emphasizes the role of intergranular liquid during the devitrification process in “snowplowing” impurities present in the matrix.

Failure Mechanisms of Particulate Two-Phase Composites

1998 ◽  
Vol 529 ◽  
Author(s):  
T. Antretter ◽  
E D. Fischer
Keyword(s):  
Residual Stresses ◽  
Crack Growth ◽  
Opening Angle ◽  
Geometrical Parameters ◽  
Two Phase ◽  
Absolute Size ◽  
The Matrix ◽  
Unit Cells ◽  
Angle Criterion ◽  
Probability Of Fracture

AbstractIn many composites consisting of hard and brittle inclusions embedded in a ductile matrix failure can be attributed to particle cleavage followed by ductile crack growth in the matrix. Both mechanisms are significantly sensitive towards the presence of residual stresses.On the one hand particle failure depends on the stress distribution inside the inclusion, which, in turn, is a function of various geometrical parameters such as the aspect ratio and the position relative to adjacent particles as well as the external load. On the other hand it has been observed that the absolute size of each particle plays a role as well and will, therefore, be taken into account in this work by means of the Weibull theory. Unit cells containing a number of quasi-randomly oriented elliptical inclusions serve as the basis for the finite element calculations. The numerical results are then correlated to the geometrical parameters defining the inclusions. The probability of fracture has been evaluated for a large number of inclusions and plotted versus the particle size. The parameters of the fitting curves to the resulting data points depend on the choice of the Weibull parameters.A crack tip opening angle criterion (CTOA) is used to describe crack growth in the matrix emanating from a broken particle. It turns out that the crack resistance of the matrix largely depends on the distance from an adjacent particle. Residual stresses due to quenching of the material tend to reduce the risk of particle cleavage but promote crack propagation in the matrix.

scholarly journals MC2: a two-phase algorithm for leveraged matrix completion

2018 ◽  
Vol 7 (3) ◽  
pp. 581-604 ◽  
Author(s):  
Armin Eftekhari ◽  
Michael B Wakin ◽  
Rachel A Ward
Keyword(s):  
Broad Class ◽  
Matrix Completion ◽  
A Priori ◽  
Total Sample ◽  
Second Phase ◽  
Sample Complexity ◽  
Two Phase ◽  
The Matrix ◽  
Leverage Scores ◽  
Uniform Random Sampling

Abstract Leverage scores, loosely speaking, reflect the importance of the rows and columns of a matrix. Ideally, given the leverage scores of a rank-r matrix $M\in \mathbb{R}^{n\times n}$, that matrix can be reliably completed from just $O (rn\log ^{2}n )$ samples if the samples are chosen randomly from a non-uniform distribution induced by the leverage scores. In practice, however, the leverage scores are often unknown a priori. As such, the sample complexity in uniform matrix completion—using uniform random sampling—increases to $O(\eta (M)\cdot rn\log ^{2}n)$, where η(M) is the largest leverage score of M. In this paper, we propose a two-phase algorithm called MC2 for matrix completion: in the first phase, the leverage scores are estimated based on uniform random samples, and then in the second phase the matrix is resampled non-uniformly based on the estimated leverage scores and then completed. For well-conditioned matrices, the total sample complexity of MC2 is no worse than uniform matrix completion, and for certain classes of well-conditioned matrices—namely, reasonably coherent matrices whose leverage scores exhibit mild decay—MC2 requires substantially fewer samples. Numerical simulations suggest that the algorithm outperforms uniform matrix completion in a broad class of matrices and, in particular, is much less sensitive to the condition number than our theory currently requires.

Symmetry, bifurcations, and chaos in a distributed respiratory control system

1994 ◽  
Vol 77 (5) ◽  
pp. 2481-2495 ◽  
Author(s):  
M. Sammon
Keyword(s):  
Chaotic Behavior ◽  
Respiratory Control ◽  
Oscillatory Behavior ◽  
Phase Switching ◽  
Control Distribution ◽  
Complex Eigenvalues ◽  
Afferent Information ◽  
Switching Functions ◽  
The Matrix ◽  
Afferent Control

A multivariate model is outlined for a distributed respiratory central pattern generator (RCPG) and its afferent control. Oscillatory behavior of the system depends on structure and symmetry of a matrix of phase-switching functions (F omega, phi) that control distribution of central excitation (CE) and inhibition (CI) within the circuit. The matrix diagonal (F omega) controls activation of CI variables as excitatory inputs are altered (e.g., central and afferent contributions to inspiratory off switch); off-diagonal terms (F phi) distribute excitations within the CI system and produce complex eigenvalues at the switching points between inspiration and expiration. For null F phi, phase switchings of saddle equilibria located at end expiration and end inspiration are overdamped all-or-nothing events; graded control of CI is seen for phi > 0. When coupling is significant (phi >> 0), CI dynamics become underdamped, admitting a domain of inputs where chaotic behavior is predictably observed. For the homogeneous RCPG (symmetric F omega, phi), CE oscillations are one-dimensional limit cycles (D = 1) or weakly chaotic (D approximately equal to 1). When perturbations from symmetry are significant, the distributed RCPG becomes partitioned where strongly chaotic oscillations (D > or = 2) and central apnea (D = 0) are seen more frequently. The equations provide means for mapping Silnikov bifurcations that alter the geometry and dimension of the breathing pattern and formalisms for discussing RCPG processing of afferent information.

scholarly journals COMPUTATIONAL MICROSTRUCTURE-BASED ANALYSIS OF RESIDUAL STRESS EVOLUTION IN METAL-MATRIX COMPOSITE MATERIALS DURING THERMOMECHANICAL LOADING

2021 ◽  
Vol 19 (2) ◽  
pp. 241
Author(s):  
Ruslan Balokhonov ◽  
Varvara Romanova ◽  
Eugen Schwab ◽  
Aleksandr Zemlianov ◽  
Eugene Evtushenko
Keyword(s):  
Residual Stress ◽  
Metal Matrix ◽  
Spatial Scales ◽  
Three Dimensional ◽  
Matrix Composites ◽  
Two Phase ◽  
Irregular Shapes ◽  
The Matrix ◽  
Stress Formation ◽  
Mechanical Fragmentation

A technique for computer simulation of three-dimensional structures of materials with reinforcing particles of complex irregular shapes observed in the experiments is proposed, which assumes scale invariance of the natural mechanical fragmentation. Two-phase structures of metal-matrix composites and coatings of different spatial scales are created, with the particles randomly distributed over the matrix and coating computational domains. Using the titanium carbide reinforcing particle embedded into the aluminum as an example, plastic strain localization and residual stress formation along the matrix-particle interface are numerically investigated during cooling followed by compression or tension of the composite. A detailed analysis is performed to evaluate the residual stress concentration in local regions of bulk tension formed under all-round and uniaxial compression of the composite due to the concave and convex interfacial asperities.

scholarly journals An Integrally Embedded Discrete Fracture Model for Flow Simulation in Anisotropic Formations

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3070
Author(s):  
Renjie Shao ◽  
Yuan Di ◽  
Dawei Wu ◽  
Yu-Shu Wu
Keyword(s):  
Flow Simulation ◽  
Fracture Model ◽  
Fluid Exchange ◽  
Two Phase ◽  
Fine Grid ◽  
Discrete Fracture Model ◽  
Matrix Fracture ◽  
Discrete Fracture ◽  
The Matrix ◽  
Anisotropic Formation

The embedded discrete fracture model (EDFM), among different flow simulation models, achieves a good balance between efficiency and accuracy. In the EDFM, micro-scale fractures that cannot be characterized individually need to be homogenized into the matrix, which may bring anisotropy into the matrix. However, the simplified matrix–fracture fluid exchange assumption makes it difficult for EDFM to address the anisotropic flow. In this paper, an integrally embedded discrete fracture model (iEDFM) suitable for anisotropic formations is proposed. Structured mesh is employed for the anisotropic matrix, and the fracture element, which consists of a group of connected fractures, is integrally embedded in the matrix grid. An analytic pressure distribution is derived for the point source in anisotropic formation expressed by permeability tensor, and applied to the matrix–fracture transmissibility calculation. Two case studies were conducted and compared with the analytic solution or fine grid result to demonstrate the advantage and applicability of iEDFM to address anisotropic formation. In addition, a two-phase flow example with a reported dataset was studied to analyze the effect of the matrix anisotropy on the simulation result, which also showed the feasibility of iEDFM to address anisotropic formation with complex fracture networks.

Observation and Mearsurement of Concentration Moments in Rapid Coarsening, Self-Stressed, Au-Ni Thin Plates

2000 ◽  
Vol 6 (S2) ◽  
pp. 360-361
Author(s):  
B. Hyde ◽  
W.T. Reynolds
Keyword(s):  
Elastic Stress ◽  
Lattice Misfit ◽  
Host Lattice ◽  
Thin Plates ◽  
Two Phase ◽  
Elastic Stresses ◽  
Buckling Stress ◽  
The Matrix ◽  
Coarsening Kinetics ◽  
Rapid Coarsening

The focus of our study is to demonstrate experimentally how elastic stress effects diffusion behavior and coarsening kinetics in a two-phase binary alloy. This work, based on the theory of Cahn and Kobayashi, focuses on elastic stresses in a thin plate. For the case of phase separation with lattice misfit between solute-rich and solute-poor phases, the diffusion of solute distorts the host lattice and causes elastic stress in the matrix. If the plate is sufficiently thin, the stress can cause the plate to buckle. The buckling stress biases the direction of diffusion, which increases the bending stress even further. Thus, the diffusion and the buckling stress are coupled; each affects the other. The interplay between the two is easiest to observe in a solution in which the solute and solvent have high misfit.

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