scholarly journals DEBUSSY 2.0: the new release of a Debye user system for nanocrystalline and/or disordered materials

2015 ◽  
Vol 48 (6) ◽  
pp. 2026-2032 ◽  
Author(s):  
Antonio Cervellino ◽  
Ruggero Frison ◽  
Federica Bertolotti ◽  
Antonietta Guagliardi
Keyword(s):  
Function Analysis ◽  
Computational Modelling ◽  
Site Occupancy ◽  
Group Symmetry ◽  
Model Parameters ◽  
General Strategy ◽  
Debye Function ◽  
Shape Information ◽  
Size Dependent ◽  
A Chain

The new release ofDEBUSSYis introduced, a free open-source package devoted to the application of the Debye function analysis of powder diffraction data from nanocrystalline, defective and/or nonperiodic materials. The general strategy of the suite remains unchanged, following a two-step approach managed by theCLAUDEandDEBUSSYprograms, respectively. The first step essentially consists in generating a database where structural, size and shape information on a nanocrystal population is stored; the second step consists in the calculation, through the Debye scattering equation, of the total diffraction pattern using the previously generated database and a set of model parameters provided by the user and then optimized by the program. The novelties lie in the computational, modelling and graphical levels, and several new programs and features have been added. Among these are a new general comprehensive input file format (.ddb) for the database generation, the automatic management of the space-group symmetry and .cif file, new nanocrystal shapes, size-dependent site occupancy factors and thermal parameters for each atomic species, new lattice expansion functions, and a newly developed algorithm for calculating the standard errors of the optimized parameters. TheCLAUDEsuite also includes a program for calculation of the pair distribution function. Last but not least, a graphical user interface, which makes it easier to edit input files, execute the programs of the suite in a chain-like way, and plot the results in an automatic or custom manner, is provided.

scholarly journals Computational modelling of cell chain migration reveals mechanisms that sustain follow-the-leader behaviour

2012 ◽  
Vol 9 (72) ◽  
pp. 1576-1588 ◽  
Author(s):  
Michelle L. Wynn ◽  
Paul M. Kulesa ◽  
Santiago Schnell
Keyword(s):  
Cancer Metastasis ◽  
Computational Modelling ◽  
Cell Movement ◽  
Cell Contact ◽  
Model Parameters ◽  
Directional Bias ◽  
Agent Based ◽  
Chain Migration ◽  
A Chain ◽  
Cell Cell

Follow-the-leader chain migration is a striking cell migratory behaviour observed during vertebrate development, adult neurogenesis and cancer metastasis. Although cell–cell contact and extracellular matrix (ECM) cues have been proposed to promote this phenomenon, mechanisms that underlie chain migration persistence remain unclear. Here, we developed a quantitative agent-based modelling framework to test mechanistic hypotheses of chain migration persistence. We defined chain migration and its persistence based on evidence from the highly migratory neural crest model system, where cells within a chain extend and retract filopodia in short-lived cell contacts and move together as a collective. In our agent-based simulations, we began with a set of agents arranged as a chain and systematically probed the influence of model parameters to identify factors critical to the maintenance of the chain migration pattern. We discovered that chain migration persistence requires a high degree of directional bias in both lead and follower cells towards the target. Chain migration persistence was also promoted when lead cells maintained cell contact with followers, but not vice-versa. Finally, providing a path of least resistance in the ECM was not sufficient alone to drive chain persistence. Our results indicate that chain migration persistence depends on the interplay of directional cell movement and biased cell–cell contact.

scholarly journals In situ high-temperature X-ray diffraction study of Sc-doped titanium oxide nanocrystallites

2020 ◽  
Vol 53 (6) ◽  
pp. 1452-1461
Author(s):  
Victor Y. Zenou ◽  
Federica Bertolotti ◽  
Antonietta Guagliardi ◽  
Brian H. Toby ◽  
Robert B. Von Dreele ◽  
...  
Keyword(s):  
High Temperature ◽  
Function Analysis ◽  
Site Occupancy ◽  
Microstructural Characterization ◽  
Rutile Phase ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
Debye Function ◽  
X Ray

Titanium dioxide is an inexpensive wide-gap highly ionic semiconductor with striking photocatalytic capabilities in several heterogeneous photoredox reactions. A small crystal size is desirable to maximize the surface area, since photocatalytic reactions occur at the surface of a photocatalyst. Presented here are the synthesis and microstructural characterization of 4 at.% Sc-doped TiO2 (4SDT) prepared by water-based co-precipitation. The crystal structure of 4SDT was examined via in situ high-temperature powder X-ray diffraction experiments from 25 to 1200°C. Rietveld analysis revealed single-phase anatase up to 875°C, while at 900°C the anatase-to-rutile phase transformation occurred and at higher temperatures additional reflections of Sc-rich phases (Sc2TiO5 from 975°C and Ti3Sc4O12 or Sc2O3 at 1200°C) were observed. Debye function analysis (DFA) was applied to model the total scattering pattern directly in reciprocal space, allowing the reconstruction of Ti vacancies. Both Rietveld and DFA methods were applied to estimate the nanocrystallite size and shape with consistent growth in crystallite size with temperature: an ellipsoid shape with equatorial ∼4.7 nm / axial (001) ∼6.9 nm at 25°C to equatorial ∼27.9 nm / axial (001) ∼39.6 nm at 900°C refined by Rietveld analysis, versus a cylinder shape with D a,b = 4.3 nm and size dispersion σ ab = 1.5 nm, L c = 4.9 nm and σ c = 2.3 nm at 25°C to D a,b = 21.4 nm, σ ab = 8.3 nm, L c = 23.9 and σ c = 10.9 nm at 900°C estimated by DFA. The microstructural changes obtained by Rietveld and DFA methods were supported by high-resolution transmission electron microscopy image analysis, as well as by the less direct nitrogen sorption techniques that provide information on the size of non-agglomerated and dense particles. The Ti site-occupancy factor showed a linear increase from 0.6–0.8 at 25°C to unity at 900°C for anatase, and from ∼0.7 at 900°C to unity at 1200°C for rutile, via Rietveld analysis and DFA.

scholarly journals There's no place like real-space: elucidating size-dependent atomic structure of nanomaterials using pair distribution function analysis

2020 ◽  
Vol 2 (6) ◽  
pp. 2234-2254 ◽  
Author(s):  
Troels Lindahl Christiansen ◽  
Susan R. Cooper ◽  
Kirsten M. Ø. Jensen
Keyword(s):  
Distribution Function ◽  
Atomic Structure ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Real Space ◽  
Size Dependent ◽  
Structure Of Nanomaterials

We review the use of pair distribution function analysis for characterization of atomic structure in nanomaterials.

scholarly journals Large-amplitude quadrupole shape mixing probed by the $(p,p^\prime)$ reaction: A model analysis

2019 ◽  
Vol 2019 (10) ◽  
Author(s):  
Koichi Sato ◽  
Takenori Furumoto ◽  
Yuma Kikuchi ◽  
Kazuyuki Ogata ◽  
Yukinori Sakuragi
Keyword(s):  
Cross Sections ◽  
Large Amplitude ◽  
Model Parameters ◽  
Channel Calculation ◽  
Prolate Shape ◽  
Coupled Channel Calculation ◽  
Transition Densities ◽  
A Chain ◽  
Coupled Channel ◽  
Shape Phase Transition

Abstract To discuss a possible observation of large-amplitude nuclear shape mixing by nuclear reaction, we employ a simple collective model and evaluate the transition densities with which the differential cross sections are obtained through the microscopic coupled-channel calculation. Assuming the spherical-to-prolate shape transition, we focus on large-amplitude shape mixing associated with the softness of the collective potential in the $\beta$ direction. We introduce a simple model based on the five-dimensional quadrupole collective Hamiltonian, which simulates a chain of isotopes that exhibit spherical-to-prolate shape phase transition. Taking $^{154}$Sm as an example and controlling the model parameters, we study how the large-amplitude shape mixing affects the elastic and inelastic proton scatterings. The calculated results suggest that the inelastic cross section of the $2_2^+$ state shows us the important role of the quadrupole shape mixing.

scholarly journals Towards the Development of an Operational Digital Twin

Vibration ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 235-265
Author(s):  
Paul Gardner ◽  
Mattia Dal Borgo ◽  
Valentina Ruffini ◽  
Aidan J. Hughes ◽  
Yichen Zhu ◽  
...  
Keyword(s):  
Model Development ◽  
Computational Modelling ◽  
Poor Performance ◽  
Predictive Performance ◽  
Physical Structure ◽  
Model Parameters ◽  
Digital Twin ◽  
Course Of Action ◽  
Shear Structure ◽  
Secondary Function

A digital twin is a powerful new concept in computational modelling that aims to produce a one-to-one mapping of a physical structure, operating in a specific context, into the digital domain. The development of a digital twin provides clear benefits in improved predictive performance and in aiding robust decision making for operators and asset managers. One key feature of a digital twin is the ability to improve the predictive performance over time, via improvements of the digital twin. An important secondary function is the ability to inform the user when predictive performance will be poor. If regions of poor performance are identified, the digital twin must offer a course of action for improving its predictive capabilities. In this paper three sources of improvement are investigated; (i) better estimates of the model parameters, (ii) adding/updating a data-based component to model unknown physics, and (iii) the addition of more physics-based modelling into the digital twin. These three courses of actions (along with taking no further action) are investigated through a probabilistic modelling approach, where the confidence of the current digital twin is used to inform when an action is required. In addition to addressing how a digital twin targets improvement in predictive performance, this paper also considers the implications of utilising a digital twin in a control context, particularly when the digital twin identifies poor performance of the underlying modelling assumptions. The framework is applied to a three-storey shear structure, where the objective is to construct a digital twin that predicts the acceleration response at each of the three floors given an unknown (and hence, unmodelled) structural state, caused by a contact nonlinearity between the upper two floors. This is intended to represent a realistic challenge for a digital twin, the case where the physical twin will degrade with age and the digital twin will have to make predictions in the presence of unforeseen physics at the time of the original model development phase.

scholarly journals A review of Debye Function Analysis

2013 ◽  
Vol 28 (S2) ◽  
pp. S2-S10 ◽  
Author(s):  
Kenneth R. Beyerlein
Keyword(s):  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Function Analysis ◽  
Reciprocal Space ◽  
Spherical Particles ◽  
Complete Agreement ◽  
Line Profiles ◽  
Debye Function

The employment of the Debye function to model line profiles in the powder diffraction pattern from small crystallites is briefly reviewed. It is also demonstrated that for the case of very small spherical particles, it is necessary to average patterns from multiple constructions of the particle to have complete agreement with reciprocal space models. In doing so it is demonstrated that the technique of Debye function analysis is best suited for systems with only a few possible atomic arrangements.

Use of Body Shape Information in Clothing Size Selection

2000 ◽  
Vol 44 (38) ◽  
pp. 715-718 ◽  
Author(s):  
Pierre Meunier
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Body Shape ◽  
Function Analysis ◽  
Three Dimensional ◽  
Shape Information ◽  
Size Selection ◽  
Best Fitting ◽  
Input Variables

To investigate the role of body shape information on clothing size selection, a sample of 143 males were measured and sized using a computerized digital-image based measurement system. Clothing sizes were initially determined by the system using traditional criteria for the long sleeve shirt, jacket and trousers of a military dress uniform. The best-fitting size was determined by trial and error based on subjective feedback and expert judgement, provided by clothing and sizing technicians. Discriminant function analysis was used to determine sizing rules for each garment, based on different sets of anthropometric input variables. Comparisons were made between the prediction performances of discriminant functions derived from traditional variables and those of functions derived from 3D landmark coordinates. The results indicate that the use of three-dimensional landmark coordinates, as input to a discriminant function analysis, is superior to the use of circumference measurements in predicting clothing sizes. The use of these landmarks is thought to improve the classification of cases by allowing a better characterization of body shape.

scholarly journals 5-(Adamantan-1-yl)-3-(benzylsulfanyl)-4-methyl-4H-1,2,4-triazole

2012 ◽  
Vol 68 (8) ◽  
pp. o2427-o2428
Author(s):  
Ebtehal S. Al-Abdullah ◽  
Ali A. El-Emam ◽  
Hazem A. Ghabbour ◽  
Suchada Chantrapromma ◽  
Hoong-Kun Fun
Keyword(s):  
Site Occupancy ◽  
Minor Component ◽  
The Other ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Π Interactions ◽  
Phenyl Rings ◽  
Independent Molecules ◽  
A Chain

In the asymmetric unit of the title adamantyl derivative, C20H25N3S, there are two crystallographic independent molecules with slightly different conformations. In one molecule, the whole benzyl group is disordered over two orientations with the refined site-occupancy ratio of 0.63 (2):0.37 (2). The dihedral angles between the 1,2,4-triazole and phenyl rings are 24.3 (8) (major component) and 25.8 (13)° (minor component) in the disordered molecule, whereas the corresponding angle is 51.53 (16)° in the other molecule. In the crystal, molecules are linked into a chain along theaaxis by a weak C—H...N interaction. Weak C—H...π interactions are also observed.

Structural Analysis of Au/TiO2Catalysts by Debye Function Analysis

1999 ◽  
Vol 183 (1) ◽  
pp. 24-31 ◽  
Author(s):  
D.A.H. Cunningham ◽  
W. Vogel ◽  
R.M.Torres Sanchez ◽  
K. Tanaka ◽  
M. Haruta
Keyword(s):  
Structural Analysis ◽  
Function Analysis ◽  
Debye Function

scholarly journals catena-Poly[barium(II)-μ2-(dimethyl sulfoxide)-κ2 O:O-bis(μ2-2,4,6-trinitrophenolato-κ4 O 2,O 1:O 1,O 6)]

IUCrData ◽  
2020 ◽  
Vol 5 (11) ◽  
Author(s):  
Bikshandarkoil R. Srinivasan ◽  
Neha U. Parsekar ◽  
Kedar U. Narvekar
Keyword(s):  
Coordination Polymer ◽  
Oxygen Atom ◽  
Dimethyl Sulfoxide ◽  
Point Group ◽  
Binding Mode ◽  
Group Symmetry ◽  
Site Symmetry ◽  
Cation Site ◽  
A Chain ◽  
The One

The asymmetric unit of the title barium coordination polymer, [Ba(C6H2N3O7)2(C2H6OS)] n , consists of a barium cation (site symmetry m) and a dimethyl sulfoxide (DMSO) ligand (point group symmetry m) and a 2,4,6-trinitrophenolate anion located in general positions. The S atom and the methyl group of DMSO are disordered over two sets of sites. The DMSO ligand bridges a pair of BaII atoms resulting in a chain extending parallel to the a axis. The unique 2,4,6-trinitrophenolate anion also bridges a pair of BaII ions via the phenolic oxygen atom, with each BaII being additionally bonded to an oxygen atom of an adjacent nitro group. The μ 2-monoatomic bridging binding mode of both types of ligands results in the formation of an infinite chain of face-sharing {BaO10} polyhedra flanked by the remaining parts of the 2,4,6-trinitrophenolato and DMSO ligands. In the one-dimensional coordination polymer, parallel chains are interlinked with the aid of C—H...O hydrogen bonds.

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