scholarly journals Three-dimensional modelling of accretion columns: spatial asymmetry and self-consistent simulations

2020 ◽  
Vol 501 (1) ◽  
pp. 564-575
Author(s):  
M I Gornostaev
Keyword(s):  
Radiation Flux ◽  
Three Dimensional ◽  
3D Models ◽  
3D Modelling ◽  
The Self ◽  
Physical Parameters ◽  
Hydrodynamic Simulations ◽  
X Ray ◽  
Self Consistent ◽  
Column Base

ABSTRACT The paper presents the results of three-dimensional (3D) modelling of the structure and the emission of accretion columns formed above the surface of accreting strongly magnetized neutron stars under the circumstances when a pressure of the photons generated in the column base is enough to determine the dynamics of the plasma flow. On the foundation of numerical radiation hydrodynamic simulations, several 3D models of accretion column are constructed. The first group of the models contains spatially 3D columns. The corresponding calculations lead to the distributions of the radiation flux over the sidewalls of the columns which are not characterized by axial symmetry. The second group includes the self-consistent modelling of spectral radiative transfer and two-dimensional spatial structure of the column, with both thermal and bulk Comptonization taken into account. The changes in the structure of the column and the shape of X-ray continuum are investigated depending on physical parameters of the model.

scholarly journals Hydrodynamics of core-collapse supernovae and their progenitors

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Bernhard Müller
Keyword(s):  
Fluid Flow ◽  
Three Dimensional ◽  
3D Models ◽  
Core Collapse ◽  
Hydrodynamic Simulations ◽  
Convective Burning ◽  
Open Questions ◽  
Self Consistent ◽  
New Challenges ◽  
Physical Realism

AbstractMulti-dimensional fluid flow plays a paramount role in the explosions of massive stars as core-collapse supernovae. In recent years, three-dimensional (3D) simulations of these phenomena have matured significantly. Considerable progress has been made towards identifying the ingredients for shock revival by the neutrino-driven mechanism, and successful explosions have already been obtained in a number of self-consistent 3D models. These advances also bring new challenges, however. Prompted by a need for increased physical realism and meaningful model validation, supernova theory is now moving towards a more integrated view that connects multi-dimensional phenomena in the late convective burning stages prior to collapse, the explosion engine, and mixing instabilities in the supernova envelope. Here we review our current understanding of multi-D fluid flow in core-collapse supernovae and their progenitors. We start by outlining specific challenges faced by hydrodynamic simulations of core-collapse supernovae and of the late convective burning stages. We then discuss recent advances and open questions in theory and simulations.

Three-Dimensional Modelling for Cultural Heritage

2021 ◽  
pp. 418-443
Author(s):  
Luis Marques ◽  
Josep Roca
Keyword(s):  
Augmented Reality ◽  
3D Modeling ◽  
Three Dimensional ◽  
Human Perception ◽  
3D Models ◽  
3D Modelling ◽  
Digital Archives ◽  
Spatial Environment ◽  
The City ◽  
Model Visualization

The creation of 3D models of urban elements is extremely relevant for urbanists constituting digital archives and being especially useful for enriching maps and databases or reconstructing and analyzing objects/areas through time, building/recreating scenarios and implementing intuitive methods of interaction. The widespread data available online offer new opportunities to generate realistic 3D models without the need to go physically to the place. This chapter aims to demonstrate the potential 3D modeling and visualization/interaction of urban elements in the city for multiple purposes, and it is organized in four main topics: The first deals with the theoretical framework regarding the bases of the human perception of the spatial environment and the importance of 3D modelling. The second and third deal with technical procedures on terrestrial/aerial data acquisition and demonstrate alternatively data gathered online to generate 3D models for the visualization of urban elements of the city, and the fourth introduces 3D model visualization within an augmented reality environment.

scholarly journals Determination of sex-related differences based on 3D reconstruction of the chinchilla (Chinchilla lanigera) vertebral column from MDCT scans

2017 ◽  
Vol 62 (No. 4) ◽  
pp. 204-210 ◽  
Author(s):  
S. Ozkadif ◽  
E. Eken ◽  
MO Dayan ◽  
K. Besoluk
Keyword(s):  
Surface Area ◽  
Body Length ◽  
Vertebral Body ◽  
Vertebral Column ◽  
Three Dimensional ◽  
3D Models ◽  
3D Modelling ◽  
3D Reconstructions ◽  
Thoracic Part

This study was undertaken to obtain and analyse, on the basis of sex, three-dimensional (3D) reconstructions obtained by a 3D computer program from two-dimensional (2D) vertebral column sections taken by multidetector computed tomography (MDCT) images, in the chinchilla. A total of 16 adult chinchillas (Chinchilla lanigera) of both sexes were used. The MDCT images were taken under general anaesthesia, and were then transferred to a personal computer on which 3D reconstructions were carried out using a 3D modelling program (Mimics 13.1). The volume, surface area and vertebral body length of each vertebra (except caudal region) forming the vertebral column were measured from the 3D models created. The ratios (in percentage) of the measurements of each vertebra (except the sacral ones) forming the vertebral column region (cervical part, thoracic part, lumbar part) were determined for statistical analysis. We detected significant differences (P < 0.05) between sexes in all vertebrae forming the vertebral column of the chinchilla with respect to volume, surface area and vertebral body length, except for C6 and L1. This study is the first to carry out 3D reconstructions of data obtained from CT images in the chinchilla and the obtained results contribute to a more detailed understanding of the anatomy of this species. Our strategy may also be useful for the design of experiments exploring the vertebral column in domestic mammals and humans.

scholarly journals Methods and uncertainty-estimations of 3D structural modelling in crystalline rocks: A case study

2017 ◽  
Author(s):  
Raphael Schneeberger ◽  
Miguel De la Varga ◽  
Daniel Egli ◽  
Alfons Berger ◽  
Florian Kober ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Test Site ◽  
3D Models ◽  
Physical Parameters ◽  
Massif Central ◽  
Fault Pattern ◽  
Crystalline Bedrock ◽  
Surface Data ◽  
3D Geometry ◽  
Zone Pattern

Abstract. Exhumed basement rocks are often dissected by faults, the latter controlling physical parameters such as rock strength, porosity, or permeability. Knowledge on the three dimensional (3D) geometry of the fault pattern and its continuation with depth is therefore of paramount importance for projects of applied geology (e.g. tunnelling, nuclear waste disposals) in crystalline bedrock. The central Aar massif (Central Switzerland) serves as study area, where we investigate the 3D geometry of the Alpine fault pattern by means of both surface (fieldwork and remote sensing) and underground ground (mapping of the Grimsel Test Site) information. The fault zone pattern consists of planar steep major faults (kilometre-scale) being interconnected with secondary relay faults (hectometre-scale). Starting with surface data, we present a workflow for structural 3D modelling of the primary faults based on a comparison of three extrapolation approaches based on: a) field data, b) Delaunay triangulation and c) a best fitting moment of inertia analysis. The quality of these surface-data-based-3D models is then tested with respect to the fit of the predictions with the underground appearance of faults. All three extrapolation approaches result in

Implementation of the self-consistent Kröner–Eshelby model for the calculation of X-ray elastic constants for any crystal symmetry

2019 ◽  
Vol 34 (2) ◽  
pp. 103-109
Author(s):  
Arnold C. Vermeulen ◽  
Christopher M. Kube ◽  
Nicholas Norberg
Keyword(s):  
Elastic Constants ◽  
Ultrasonic Waves ◽  
The Self ◽  
Crystal Symmetry ◽  
Intermediate Step ◽  
X Rays ◽  
X Ray ◽  
Eshelby Inclusion ◽  
Eshelby Model ◽  
Self Consistent

In this paper, we will report about the implementation of the self-consistent Kröner–Eshelby model for the calculation of X-ray elastic constants for general, triclinic crystal symmetry. With applying appropriate symmetry relations, the point groups of higher crystal symmetries are covered as well. This simplifies the implementation effort to cover the calculations for any crystal symmetry. In the literature, several models can be found to estimate the polycrystalline elastic properties from single crystal elastic constants. In general, this is an intermediate step toward the calculation of the polycrystalline response to different techniques using X-rays, neutrons, or ultrasonic waves. In the case of X-ray residual stress analysis, the final goal is the calculation of X-ray Elastic constants. Contrary to the models of Reuss, Voigt, and Hill, the Kröner–Eshelby model has the benefit that, because of the implementation of the Eshelby inclusion model, it can be expanded to cover more complicated systems that exhibit multiple phases, inclusions or pores and that these can be optionally combined with a polycrystalline matrix that is anisotropic, i.e., contains texture. We will discuss a recent theoretical development where the approaches of calculating bounds of Reuss and Voigt, the tighter bounds of Hashin–Shtrikman and Dederichs–Zeller are brought together in one unifying model that converges to the self-consistent solution of Kröner–Eshelby. For the implementation of the Kröner–Eshelby model the well-known Voigt notation is adopted. The 4-rank tensor operations have been rewritten into 2-rank matrix operations. The practical difficulties of the Voigt notation, as usually concealed in the scientific literature, will be discussed. Last, we will show a practical X-ray example in which the various models are applied and compared.

scholarly journals Configuration of a Magnetic Cloud From Solar Orbiter and Wind Spacecraft In-situ Measurements

2021 ◽  
Vol 9 ◽  
Author(s):  
Qiang Hu ◽  
Wen He ◽  
Lingling Zhao ◽  
Edward Lu
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Flux Rope ◽  
3D Models ◽  
Field Configuration ◽  
Magnetic Clouds ◽  
Physical Parameters ◽  
The Sun ◽  
Wind Spacecraft

Coronal mass ejections (CMEs) represent one type of the major eruption from the Sun. Their interplanetary counterparts, the interplanetary CMEs (ICMEs), are the direct manifestations of these structures when they propagate into the heliosphere and encounter one or more observing spacecraft. The ICMEs generally exhibit a set of distinctive signatures from the in-situ spacecraft measurements. A particular subset of ICMEs, the so-called Magnetic Clouds (MCs), is more uniquely defined and has been studied for decades, based on in-situ magnetic field and plasma measurements. By utilizing the latest multiple spacecraft measurements and analysis tools, we report a detailed study of the internal magnetic field configuration of an MC event observed by both the Solar Orbiter (SO) and Wind spacecraft in the solar wind near the Sun-Earth line. Both two-dimensional (2D) and three-dimensional (3D) models are applied to reveal the flux rope configurations of the MC. Various geometrical as well as physical parameters are derived and found to be similar within error estimates for the two methods. These results quantitatively characterize the coherent MC flux rope structure crossed by the two spacecraft along different paths. The implication for the radial evolution of this MC event is also discussed.

Two new isostructural mercury(II) complexes involving the N-heterocyclic 1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole ligand: syntheses, structures and properties

2017 ◽  
Vol 73 (4) ◽  
pp. 314-318 ◽  
Author(s):  
Xu Wei ◽  
Jian-Hua Li ◽  
Qiu-Ying Huang ◽  
Xiang-Ru Meng
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Ir Spectra ◽  
Self Assembly ◽  
Three Dimensional ◽  
The Self ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heterocyclic Ligand ◽  
Structures And Properties

The unsymmetrical N-heterocyclic ligand 1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole (bmi) has three potential N-atom donors and can act in monodentate or bridging coordination modes in the construction of complexes. In addition, the bmi ligand can adopt different coordination conformations, resulting in complexes with different structures due to the presence of the flexible methylene spacer. Two new complexes, namely bis{1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole-κN3}dibromidomercury(II), [HgBr2(C10H9N5)2], and bis{1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole-κN3}diiodidomercury(II), [HgI2(C10H9N5)2], have been synthesized through the self-assembly of bmi with HgBr2or HgI2. Single-crystal X-ray diffraction shows that both complexes are mononuclear structures, in which the bmi ligands coordinate to the HgIIions in monodentate modes. In the solid state, both complexes display three-dimensional networks formed by a combination of hydrogen bonds and π–π interactions. The IR spectra and PXRD patterns of both complexes have also been recorded.

scholarly journals Self-Assembly of Antiferromagnetically-Coupled Copper(II) Supramolecular Architectures with Diverse Structural Complexities

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5549 ◽  
Author(s):  
Santokh S. Tandon ◽  
Scott D. Bunge ◽  
Neil Patel ◽  
Esther C. Wang ◽  
Laurence K. Thompson
Keyword(s):  
Schiff Base ◽  
Self Assembly ◽  
Three Dimensional ◽  
The Self ◽  
Basic Building Block ◽  
Schiff Base Ligands ◽  
X Ray ◽  
Supramolecular Architectures ◽  
Hydroxy Groups ◽  
New Discovery

The self-assembly of 2,6-diformyl-4-methylphenol (DFMP) and 1-amino-2-propanol (AP)/2-amino-1,3-propanediol (APD) in the presence of copper(II) ions results in the formation of six new supramolecular architectures containing two versatile double Schiff base ligands (H3L and H5L1) with one-, two-, or three-dimensional structures involving diverse nuclearities: tetranuclear [Cu4(HL2−)2(N3)4]·4CH3OH·56H2O (1) and [Cu4(L3−)2(OH)2(H2O)2] (2), dinuclear [Cu2(H3L12−)(N3)(H2O)(NO3)] (3), polynuclear {[Cu2(H3L12−)(H2O)(BF4)(N3)]·H2O}n (4), heptanuclear [Cu7(H3L12−)2(O)2(C6H5CO2)6]·6CH3OH·44H2O (5), and decanuclear [Cu10(H3L12−)4(O)2(OH)2(C6H5CO2)4] (C6H5CO2)2·20H2O (6). X-ray studies have revealed that the basic building block in 1, 3, and 4 is comprised of two copper centers bridged through one μ-phenolate oxygen atom from HL2− or H3L12−, and one μ-1,1-azido (N3−) ion and in 2, 5, and 6 by μ-phenoxide oxygen of L3− or H3L12− and μ-O2− or μ3-O2− ions. H-bonding involving coordinated/uncoordinated hydroxy groups of the ligands generates fascinating supramolecular architectures with 1D-single chains (1 and 6), 2D-sheets (3), and 3D-structures (4). In 5, benzoate ions display four different coordination modes, which, in our opinion, is unprecedented and constitutes a new discovery. In 1, 3, and 5, Cu(II) ions in [Cu2] units are antiferromagnetically coupled, with J ranging from −177 to −278 cm−1.

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