Analytical expressions for steady-state component profiles of irradiated substitutional alloys near point defect sinks

1992 ◽  
Vol 186 (3) ◽  
pp. 269-276 ◽  
Author(s):  
V.A. Pechenkin ◽  
G.A. Epov
Keyword(s):  
Steady State ◽  
Point Defect ◽  
Analytical Expressions ◽  
Substitutional Alloys ◽  
State Component

Steady-state point-defect diffusion profiles in solids during irradiation

1974 ◽  
Vol 23 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Nghi Q. Lam ◽  
Steven J. Rothman ◽  
Rudolf Sizmanns
Keyword(s):  
Steady State ◽  
Point Defect ◽  
Defect Diffusion ◽  
State Point ◽  
Diffusion Profiles

scholarly journals Axisymmetric viscous gravity currents flowing over a porous medium

2009 ◽  
Vol 622 ◽  
pp. 135-144 ◽  
Author(s):  
MELISSA J. SPANNUTH ◽  
JEROME A. NEUFELD ◽  
J. S. WETTLAUFER ◽  
M. GRAE WORSTER
Keyword(s):  
Porous Medium ◽  
Steady State ◽  
Gravity Current ◽  
Gravity Currents ◽  
Constant Input ◽  
Radial Extent ◽  
Vertically Aligned ◽  
Analytical Expressions ◽  
Permeability Structure ◽  
Good Agreement

We study the axisymmetric propagation of a viscous gravity current over a deep porous medium into which it also drains. A model for the propagation and drainage of the current is developed and solved numerically in the case of constant input from a point source. In this case, a steady state is possible in which drainage balances the input, and we present analytical expressions for the resulting steady profile and radial extent. We demonstrate good agreement between our experiments, which use a bed of vertically aligned tubes as the porous medium, and the theoretically predicted evolution and steady state. However, analogous experiments using glass beads as the porous medium exhibit a variety of unexpected behaviours, including overshoot of the steady-state radius and subsequent retreat, thus highlighting the importance of the porous medium geometry and permeability structure in these systems.

The Influence of Time Truncation on Phase Angle Measurement Principle

2014 ◽  
Vol 668-669 ◽  
pp. 957-960
Author(s):  
Na Na Chang ◽  
Hai Bao
Keyword(s):  
Fourier Transform ◽  
Steady State ◽  
Theoretical Calculation ◽  
Phase Angle ◽  
Measurement Data ◽  
Angle Measurement ◽  
Signal Phase ◽  
Measurement Principle ◽  
Dc Component ◽  
State Component

Real-time accurate voltage phase angle measurement data has a very important significance to monitor and analyze the power system, and phase angle measurement principle of Fourier transform plays an important role in the theoretical calculations and engineering applications. The dynamic sinusoidal voltage signal contains two parts of the sinusoidal steady-state component and decaying DC component, and the decaying DC component having a continuous spectrum, at the frequency corresponding to the sinusoidal steady-state component must have a non-zero value, making dynamic signal phase than steady signal phase has one extra deviation angle. Considering Fourier transform method and theory of engineering application are different, this paper only considered the application conditions of time truncation, analyzes continuous Fourier transform under a real eigenvalue and a pair of conjugate complex roots condition, then compared with the theoretical calculation, for the two case of limited time integration and theoretical calculation condition, the phase angle difference and influencing factors are given.

The stress-driven redistribution of point defects in the vicinity of crack-like singularities

1990 ◽  
Vol 427 (1872) ◽  
pp. 1-23 ◽  
Keyword(s):  
Steady State ◽  
Stress Field ◽  
Grain Boundary ◽  
Point Defect ◽  
Slip Band ◽  
Point Defects ◽  
Elastic Interaction ◽  
Mode Ii ◽  
Fracture Of Materials ◽  
Kinetics Of

The most important term in the energy of the elastic interaction between a crack and a point defect is presented and used to estimate the kinetics of redistribution of point defects in the stress field of an isolated crack under mode II load and a slip band impinging against a grain boundary sink. Our analyses show that the point defects should migrate only to the tip of the crack, whereas they should enter both into the slip band tip and along the adjacent boundary interface. Explicit results are obtained for the concentrations, the number and flux distributions as well as the total numbers segregated in the transient depletion and the steady-state irradiation situation and serve to reinforce previous conclusions regarding the importance of such stress-driven processes in the fracture of materials.

Modulation of excitatory amino acid responses in rat dorsal horn neurons by tachykinins

1992 ◽  
Vol 68 (1) ◽  
pp. 265-286 ◽  
Author(s):  
K. I. Rusin ◽  
P. D. Ryu ◽  
M. Randic
Keyword(s):  
Steady State ◽  
Substance P ◽  
Dorsal Horn ◽  
Peak Amplitude ◽  
Neurokinin A ◽  
Induced Current ◽  
Simultaneous Application ◽  
Transient Component ◽  
Nmda Current ◽  
State Component

1. In freshly isolated spinal dorsal horn (DH) neurons (laminae I-III) of the young rat, the effects of tachykinins (substance P, neurokinin A) on inward current induced by excitatory amino acids were studied under whole-cell voltage-clamp conditions. 2. When the cells were clamped to a holding potential of -60 mV, a simultaneous application of N-methyl-D-aspartate (NMDA) (10(-4) M) and substance P (SP) (2 x 10(-9)-10(-7) M) for 10 s reversibly enhanced (by 129.6 +/- 8.2%, mean +/- SE) the peak amplitude of the initial transient component of the NMDA-induced current in approximately 60% of the examined cells and reduced it (to 83.3 +/- 2.7%) in 27% of the cells. In addition, SP produced an increase (by 133.6 +/- 11.7%) or a small decrease (to 85.9 +/- 1.4%) in the steady-state component of the NMDA response. In difference to SP, a simultaneous application of NMDA (10(-4) M) and neurokinin A (NKA) (10(-10)-10(-7) M) reversibly suppressed (to 86.8 +/- 2.1%) the peak amplitude of the NMDA-induced current in 75% of the examined cells. 3. The NMDA-induced currents were modulated by tachykinins not only during the coadministration but up to 20 min after the removal of the peptide. SP potentiated the initial peak NMDA current by 147.9 +/- 8.1% in 78% of examined cells and decreased it (76.3 +/- 5.7%) in 11% of cells. The potentiating effect was concentration-dependent (range: 10(-11)-10(-8) M) and reversible, but it was reduced with repeated applications. In addition, SP increased (by 125.4 +/- 3.6%) or reduced (to 86.0 +/- 1.8%) the steady-state component of the NMDA response. 4. When the single DH neurons were exposed to SP or NKA for 30 s-7 min before the testing of the NMDA responses, tachykinins had two distinct effects on the peak amplitude of the transient component of the NMDA-induced current, consisting of an initial depression (SP: to 64.8 +/- 2.1%; NKA: to 76.3 +/- 4.4%) followed by a potentiation (SP: by 146.6 +/- 6.8%; NKA: by 178.4 +/- 35.2%). The enhancing effect in some cells lasted less than or equal to 1 h. 5. A claimed novel nonselective tachykinin antagonist, spantide II (10(-8) M) coadministered with NMDA (10(-4) M), slightly depressed the peak component of NMDA-induced current. In addition, it effectively blocked the SP-induced potentiation of the responses of DH neurons to NMDA.(ABSTRACT TRUNCATED AT 400 WORDS)

Steady-State Component of Three-Dimensional Slab-on-Grade Foundation Heat Transfer

2000 ◽  
Vol 123 (1) ◽  
pp. 18-29 ◽  
Author(s):  
Pirawas Chuangchid ◽  
Moncef Krarti
Keyword(s):  
Steady State ◽  
Heat Loss ◽  
Parametric Analysis ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
U Value ◽  
Rectangular Slab ◽  
Steady State Heat ◽  
Profile Estimation ◽  
State Component

General semi-analytical solutions for the steady-state heat conduction problems for circular and three-dimensional rectangular slab-on-grade floors with uniform insulation are presented. The soil temperature field, and the total slab heat loss are presented and analyzed using the Interzone Temperature Profile Estimation (ITPE) technique. A parametric analysis is conducted to determine the effect of thermal insulation U-value, slab size, and water table depth on the total slab heat loss. In particular, it was found that the total slab heat loss is independent of its shape but is strongly affected by the slab size and thermal characteristics.

Sign in / Sign up

Export Citation Format

Share Document