scholarly journals PROCESSING RESONANCE SELF-SHIELDING EFFECT OF GADOLINIA BASED ON IMPTOVED SUPERCELL SCHEME

2021 ◽  
Vol 247 ◽  
pp. 02031
Author(s):  
Jikui Li ◽  
Tiejun Zu ◽  
Wen Yin ◽  
Liangzhi Cao
Keyword(s):  
Cross Sections ◽  
Interpolation Method ◽  
Shielding Effect ◽  
Group Method ◽  
Local Effects ◽  
Correction Formula ◽  
Resonance Effects ◽  
Shadowing Effect ◽  
Low Efficiency ◽  
Shielding Effects

An improved supercell scheme has been proposed in this paper to efficiently and accurately process resonance self-shielding effect of gadolinia. Resonance effects are classified into global shadowing effect and local effects involving resonance interference, spatial self-shielding effects. Two categories of effects are decoupled and treated respectively based on different 1-D cylindrical pins. Hyperfine group method is applied to obtain multi-group cross sections for each 1-D pin. Afterwards, two categories of effects are coupled based on a correction formula. Because of the low efficiency for Carlvik method to compute collision probabilities in hyperfine group method, online tabulation and interpolation method is developed to accelerate gaining collision probabilities. The proposed scheme is verified against the problems of 3×3 pins with gadolinia rod, VERA 2O assembly with 12 gadolinia rods and VERA 2P with 24 gadolinia rods. The numerical results suggest promising consistence of multi-group cross sections and eigenvalues between the proposed scheme and reference solutions.

scholarly journals GEOMETRIC MODELING OF A SHAPE OF PARALLELOGRAM PLATES IN A PROBLEM OF FREE VIBRATIONS USING CONFORMAL RADII

2021 ◽  
pp. 143-159
Author(s):  
A.A. Chernyaev ◽  
Keyword(s):  
Cross Sections ◽  
Geometric Modeling ◽  
Interpolation Method ◽  
Geometric Characteristic ◽  
Free Vibrations ◽  
Theory Of Elasticity ◽  
Constant Thickness ◽  
Basic Frequency ◽  
Plate Vibrations ◽  
The Subject

The paper considers a method of geometric modeling applied when solving basic twodimensional problems of the theory of elasticity and structural mechanics, in particular the applied problems of engineering. The subject of this study is vibrations of thin elastic parallelogram plates of constant thickness. To determine a basic frequency of vibrations, the interpolation method based on the geometric characteristic of the shape of plates (membrane, cross sections of a rod) is proposed. This characteristic represents a ratio of interior and exterior conformal radii of the plate. As is known from the theory of conformal mappings, conformal radii are those obtained by mapping of a plate onto the interior and exterior of a unit disk. The paper presents basic terms, tables, and formulas related to the considered geometric method with a comparative analysis of the curve diagrams obtained using various interpolation formulas. The original computer program is also developed. The main advantage of the proposed method of determining the basic frequency of plate vibrations is a graphic representation of results that allows one to accurately determine the required solution on the graph among the other solutions corresponding to the considered case of parallelogram plates. Although there are many known approximate approaches, which are used to solve the considered problems, only geometric modeling technique based on the conformal radii ratio gives such an opportunity.

Neutron Up-Scattering Effect in Refined Energy Group Structure

2016 ◽  
Author(s):  
Qingming He ◽  
Hongchun Wu ◽  
Yunzhao Li ◽  
Liangzhi Cao ◽  
Tiejun Zu
Keyword(s):  
Cross Sections ◽  
Group Structure ◽  
Scattering Matrix ◽  
The Self ◽  
Shielding Effect ◽  
Doppler Broadening ◽  
Fuel Temperature ◽  
Energy Group ◽  
Scattering Effect ◽  
Mc Method

Aiming at generating a 361-group library, this paper investigated neutron up-scattering effect in the 361-group Santamarina-Hfaiedh Energy Mesh (SHEM). Firstly, the Doppler Broadening Rejection Correction (DBRC) method is implemented to consider the neutron up-scattering effect in Monte Carlo (MC) method. Then the MC method is employed to prepare resonance integral table and scattering matrix for afterward calculation. Numerical results show that the neutron up-scattering affects kinf by ∼200 pcm at most for UO2 pin cell problems in the 361-group SHEM, while the fuel temperature coefficient (FTC) is also influenced by 12∼13%. It has also been found that both of the above two influences acts through scattering matrix rather than self-shielded absorption cross sections. In addition, the self-shielding effect of cladding is studied and it’s been found that it affects kinf by 30∼70 pcm.

Observation of resonance effects in the relative partial photoionization cross sections of the d bands of M(CO)6, M = Cr, Mo and W

1986 ◽  
Vol 125 (2) ◽  
pp. 97-100 ◽  
Author(s):  
Glyn Cooper ◽  
Jennifer C. Green ◽  
Martin P. Payne ◽  
Barry R. Dobson ◽  
Ian H. Hillier
Keyword(s):  
Cross Sections ◽  
Resonance Effects

Interaction of a screw dislocation with a crack in an anisotropic body

1991 ◽  
Vol 6 (12) ◽  
pp. 2578-2584 ◽  
Author(s):  
Tong-Yi Zhang ◽  
J.E. Hack
Keyword(s):  
Screw Dislocation ◽  
Stress Component ◽  
Anisotropic Body ◽  
Image Force ◽  
Shielding Effect ◽  
Crack Plane ◽  
Mode Iii ◽  
Mode Iii Crack ◽  
Isotropic Media ◽  
Shielding Effects

The stress field, image force, and shielding effect of a screw dislocation in the vicinity of a Mode III crack were formulated for both semi-infinite and finite length cracks. The results show that there is an abnormal stress component, ŝ31, on the crack plane. This leads to a nonzero image force along the axis perpendicular to the crack plane when the dislocation is located on the crack plane. However, the abnormal stress component and image force disappear for orthotropic and isotropic media. The image force along a slip plane has the same expression as in isotropic media with an effective shear modulus. Generally the shielding effects are the same as in isotropic media. The anisotropy changes only the magnitude of the shielding effects. The case of multiple dislocations is also discussed.

scholarly journals A FULL REFERENCE APOLLO3® DETERMINISTIC SCHEME FOR THE JHR MATERIAL TESTING REACTOR

2021 ◽  
Vol 247 ◽  
pp. 06003
Author(s):  
Matthieu Lebreton ◽  
Julien Politello ◽  
Jean-François Vidal ◽  
Gérald Rimpault
Keyword(s):  
Cross Sections ◽  
Method Of Characteristics ◽  
Aluminum Matrix ◽  
Material Testing ◽  
Group Method ◽  
Fuel Assemblies ◽  
Radial Reflector ◽  
Set Up ◽  
Under Construction ◽  
Core Characteristics

JHR is a new material testing reactor under construction at CEA Cadarache. Its high flux core contains 37 fuel assemblies loaded along concentric rings into alveolus of an aluminum matrix. For the operation of the reactor, twenty-seven of these fuel assemblies hovnst hafnium rods in their center while the other ones but also the beryllium radial reflector can accommodate experimental devices. In order to accurately predict its operating core characteristics but also its irradiation performance, a recently developed scheme based on the APOLLO3® platform is being developed which uses the sub-group method for spatial self-shielding, the 2D method of characteristics and the 3D unstructured conform MINARET Sn transport solver. A 2D model of JHR has been built and optimized for calculating, at the lattice step, the self-shielded and condensed cross sections thanks to the sub-group method and the method of characteristics. Results are benchmarked against a TRIPOLI-4® stochastic reference calculation. A more refined spatial mesh gives better results on fission rates and reactivity compared to the ones of the former APOLLO2 scheme. The classical 2-step calculations use the hypothesis of infinite lattice configuration, which is reasonable for the assemblies close to the center but not for peripheral ones. Hence, a new approach is being set up taking into account the surrounding of each assembly. The newly 3-step scheme uses the Sn solver MINARET and gives better results than the traditional 2-step scheme. This approach will be applied to a 3D modelling of the heterogeneous JHR core configurations incorporating experimental devices and enabling burn up calculations.

Study on the Flow Field and the Shielding Effect of a Hemisphere Artificial Reef and Other Alike Sub-Sea Structures

2019 ◽  
Author(s):  
Lin Zhao ◽  
Junwei Tan
Keyword(s):  
Flow Field ◽  
Artificial Reef ◽  
Flow Fields ◽  
Living Environment ◽  
Shielding Effect ◽  
Ecological Environment ◽  
Artificial Structures ◽  
Marine Life ◽  
Shadowing Effect

Abstract A hemisphere artificial reef is designed and numerically simulated in this paper. Investigations of this structure subject to various flow fields with different hole ratios and different diameter are carried out. Besides, the effect of the hemisphere structure to the surrounding flow field is discussed. Further studies are carried out for an array of hemisphere structures of this kind. Comparing to the traditional artificial structures like the trapezoidal reefs and square reefs, the hemisphere reef can not only produce a qualified ascending flow field, but his internal shadowing effect is not negligible.This area then can provide a better ocean ecological environment and living environment to attach and promote the marine life.

scholarly journals Dynamic Measurement of Foam-Sized Yarn Properties from Yarn Sequence Images

2018 ◽  
Vol 18 (3) ◽  
pp. 314-322 ◽  
Author(s):  
Bo Zhu ◽  
Zhongjian Li ◽  
Xinwei Cao ◽  
Jianli Liu ◽  
Weidong Gao
Keyword(s):  
Image Analysis ◽  
Film Thickness ◽  
Cross Sections ◽  
Clustering Algorithm ◽  
Dynamic Method ◽  
Penetration Rate ◽  
Dynamic Measurement ◽  
Dynamic Threshold ◽  
Yarn Properties ◽  
Low Efficiency

Abstract Unlike the normal sizing method, the foam sizing had been proven to be a low-add-on technology. To investigate the effect of foam sizing, film thickness, sized-yarn evenness, and size penetration rate were necessary to evaluate the performances of foam-sized yarns. However, the conventional image analysis of sized-yarn cross sections primarily relied on artificial testing with a low efficiency. This paper proposed a novel dynamic method to measure the sized-yarn properties including film thickness, sized-yarn evenness, and size penetration rate based on yarn sequence images captured from a moving yarn. A method of dynamic threshold module was adopted to obtain threshold for segmenting yarns in the sequence images. K-means clustering algorithm was applied to segment pixels of the images into yarn and background. To further remove burrs and noise in the images, two judgment templates were carried out to extract the information of yarn core. The film thickness, sized-yarn evenness, and size penetration rate were measured based on the yarn core of each frame in sequence images. In order to compare with the experimental results of the dynamic method, the yarn properties of the same samples were tested by static and artificial testing. Results revealed that the proposed method could efficiently and accurately detect the film thickness, sized-yarn evenness, and size penetration rate.

The shielding effect of metal complexes on the binding affinities of ligands to metalloproteins

2019 ◽  
Vol 21 (1) ◽  
pp. 205-216 ◽  
Author(s):  
Deliang Chen ◽  
Yibao Li ◽  
Wei Guo ◽  
Yongdong Li ◽  
Tor Savidge ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Metal Complexes ◽  
Shielding Effect ◽  
Binding Affinities ◽  
Ligand Interactions ◽  
Metal Ligand ◽  
Shielding Effects

The contributions of metal–ligand interactions to the ligand binding affinities are largely reduced by the shielding effects of metal complexes.

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