scholarly journals Attention with Residual Resistance in Structural Repairs

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
José Emidio Alexandrino Bezerra ◽  
Antônio Eduardo Bezerra Cabral ◽  
Angel Oshiro
Keyword(s):  
Residual Resistance

scholarly journals Aircraft Impact Effects on an Aged NPP

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 816
Author(s):  
Rosa Lo Frano
Keyword(s):  
Nuclear Power ◽  
Military Aircraft ◽  
Residual Resistance ◽  
Plant Safety ◽  
Need To Evaluate ◽  
Target Wall ◽  
Impact Area ◽  
Wall Perforation ◽  
The Impact ◽  
Loss Of Strength

The impact of an aircraft is widely known to be one of the worst events that can occur during the operation of a plant (classified for this reason as beyond design). This can become much more catastrophic and lead to the loss of strength of/collapse of the structures when it occurs in the presence of ageing (degradation and alteration) materials. Therefore, since the performance of all plant components may be affected by ageing, there is a need to evaluate the effect that aged components have on system performance and plant safety. This study addresses the numerical simulation of an aged Nuclear Power Plant (NPP) subjected to a military aircraft impact. The effects of impact velocity, direction, and location were investigated together with the more unfavorable conditions to be expected for the plant. The modelling method was also validated based on the results obtained from the experiments of Sugano et al., 1993. Non-linear analyses by means of finite element (FE) MARC code allowed us to simulate the performance of the reinforced concrete containment building and its impact on plant availability and reliability. The results showed that ageing increases a plant’s propensity to suffer damage. The damage at the impact area was confirmed to be dependent on the type of aircraft involved and the target wall thickness. The greater the degradation of the materials, the lower the residual resistance capacity, and the greater the risk of wall perforation.

scholarly journals Phonon residual resistance of pure crystals

2015 ◽  
Vol 29 (29) ◽  
pp. 1550206
Author(s):  
A. I. Agafonov
Keyword(s):  
Electric Field ◽  
Constant Electric Field ◽  
Finite Thickness ◽  
Mean Free Path ◽  
Residual Resistivity ◽  
Boltzmann Transport ◽  
Residual Resistance ◽  
Temperature Resistance ◽  
Electron Mean Free Path ◽  
The Ideal

In this paper, using the Boltzmann transport equation, we study the zero temperature resistance of perfect metallic crystals of a finite thickness d along which a weak constant electric field E is applied. This resistance, hereinafter referred to as the phonon residual resistance, is caused by the inelastic scattering of electrons heated by the electric field, with emission of long-wave acoustic phonons and is proportional to [Formula: see text]. Consideration is carried out for Cu, Ag and Au perfect crystals with the thickness of about 1 cm, in the fields of the order of 1 mV/cm. Following the Matthiessen rule, the resistance of the pure crystals, the thicknesses of which are much larger than the electron mean free path is represented as the sum of both the impurity and phonon residual resistances. The condition on the thickness and field is found at which the low-temperature resistance of pure crystals does not depend on their purity and is determined by the phonon residual resistivity of the ideal crystals. The calculations are performed for Cu with a purity of at least 99.9999%.

Influence of Modulation Wavelength Induced Order on the Physical Properties of Nb/Rare Earth Superlattices

1984 ◽  
Vol 37 ◽  
Author(s):  
L. H. Greene ◽  
W. L. Feldmann ◽  
J. M. Rowell ◽  
B. Batlogg ◽  
R. Hull ◽  
...  
Keyword(s):  
Rare Earth ◽  
Room Temperature ◽  
Room Temperature Resistivity ◽  
Residual Resistance ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Residual Resistance Ratio ◽  
Temperature Resistivity ◽  
Modulation Wavelength

AbstractWe report the observation of a higher degree of preferred crystalline orientation in Nb/rare earth superlattices for modulation wavelengths in the range of 200 Å to 500 Å than that exhibited by single component films. All films and multilayers are sputter deposited onto room temperature sapphire substrates. Electronic transport measurements also show that the residual resistance ratio is higher and the room temperature resistivity is lower than for multilayers of either greater or lower periodicities. Transmission electron micrographs (TEM) showing excellent layering, grain size comparable to the layer thickness, and evidence of some degree of epitaxy are presented.

scholarly journals Round Robin Test of Residual Resistance Ratio of Nb3Sn Composite Superconductors

2018 ◽  
Vol 28 (2) ◽  
pp. 1-5 ◽  
Author(s):  
Teruo Matsushita ◽  
Edmund S. Otabe ◽  
Dongho Kim ◽  
Taejong Hwang ◽  
Huixian Gao ◽  
...  
Keyword(s):  
Round Robin ◽  
Resistance Ratio ◽  
Residual Resistance ◽  
Round Robin Test ◽  
Composite Superconductors ◽  
Residual Resistance Ratio

A Concept of the Triple-Hull Frigate

2000 ◽  
Vol 37 (03) ◽  
pp. 141-145
Author(s):  
Victor A. Dubrovskiy
Keyword(s):  
Hydrodynamic Interaction ◽  
Bending Moment ◽  
Resistance Coefficient ◽  
Residual Resistance ◽  
Advantages And Disadvantages ◽  
General Arrangement ◽  
Hull Structure ◽  
Longitudinal Bending ◽  
Transverse Stability ◽  
Wetted Area

Ships with outriggers, such as multihull vessels, are defined and their advantages and disadvantages described. The general feasibility of a hull with a small waterplane area is considered as a method for development of an outriggered frigate design. The main dimensions, general arrangement, and hull structure of this design are offered along with calculations of initial transverse stability, longitudinal bending moment in waves, wetted area, residual resistance coefficient of the single hull, as well as the hydrodynamic interaction of the main hull with the outriggers.

scholarly journals DC Flashover Dynamic Model of Post Insulator under Non-Uniform Pollution between Windward and Leeward Sides

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2345 ◽  
Author(s):  
Zhijin Zhang ◽  
Shenghuan Yang ◽  
Xingliang Jiang ◽  
Xinhan Qiao ◽  
Yingzhu Xiang ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Density Ratio ◽  
Leeward Side ◽  
Arc Length ◽  
Residual Resistance ◽  
Factors Affecting ◽  
Flashover Voltage ◽  
Layer Resistance ◽  
Good Concordance ◽  
Post Insulator

Experience shows that under unidirectional wind or certain terrain, the surface of post insulators is non-uniformly polluted between windward and leeward sides, which affects the flashover characteristics. In this paper, a formulation of residual pollution layer resistance was proposed under this non-uniformity and a typical post insulator was taken as an example to analyze and calculate its residual resistance. The theoretical resistance was verified by numerical simulations using COMSOL Multiphysics. The proposed resistance formulation was then implemented in a DC flashover dynamic model to determine the flashover voltage (Ucal), which was validated by artificial flashover tests. Then the factors affecting DC flashover voltage were analyzed. Research results indicate that: the residual resistance formulation agrees well with simulation results, especially when the arc length exceeds 70% of the leakage distance. The good concordance between theoretical and experimental flashover voltages with most relative error within ±10%, validates the flashover model and its residual resistance formulation. Ucal gets impaired under this non-uniformity. The degree of reduction is related to salt deposit density ratio (m) of windward to leeward side and leeward side area proportion (k).

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