A geometric upper bound on the mean first nearest neighbour distance between particles in three-dimensional microstructures

2004 ◽  
Vol 52 (17) ◽  
pp. 5165-5168 ◽  
Author(s):  
A. Tewari ◽  
A.M. Gokhale
Keyword(s):  
Upper Bound ◽  
Three Dimensional ◽  
Nearest Neighbour ◽  
Neighbour Distance ◽  
The Mean

Struktur von Schmelzen aus dem System Wismut-Antimon mittels Neutronenbeugung

1976 ◽  
Vol 31 (1) ◽  
pp. 90-101 ◽  
Author(s):  
Peter Lamparter ◽  
Siegfried Steeb ◽  
Walter Knoll
Keyword(s):  
Neutron Diffraction ◽  
Coordination Number ◽  
Covalent Binding ◽  
The Other ◽  
Nearest Neighbour ◽  
Neighbour Distance ◽  
The Mean ◽  
The One ◽  
Subsidiary Maxima ◽  
Versus Concentration

Neutron diffraction work (λ = 0.695 Å) was done with molten Bi-Sb-alloys in the temperature range between 550 and 750 °C. Furthermore molten Bi was investigated at 300 °C. The interference functions show subsidiary maxima especially for alloys with higher Sb-concentrations. Evaluation yields, that the melts contain two different kinds of structure:a) The one kind shows coordination number 9 and a statistical distribution of the atoms of two components. This kind is more inetal-like.b) The other kind shows coordination number 3, consists of non-centered tetrahedra with smaller nearest neighbour distance. It shows covalent binding.In molten Sb the nearest neighbour distance amounts up to 3.16 - 3.19 Å for theo ne kind and up to 2.64 -2.78 Å fort he other kind, which yields an mean distance of 2.99 Å, which was observed. The dependence of the concentration of the statistical kind of meld, of the (Sb)4-, and the (Bi)4-kind from the concentration of the whole melt is given.By the model described the run of the measured mean coordination number and the mean distance versus concentration can be well explained.

scholarly journals Dominating lengthscales of zebrafish collective behaviour

2022 ◽  
Vol 18 (1) ◽  
pp. e1009394
Author(s):  
Yushi Yang ◽  
Francesco Turci ◽  
Erika Kague ◽  
Chrissy L. Hammond ◽  
John Russo ◽  
...  
Keyword(s):  
Collective Motion ◽  
Persistence Length ◽  
Three Dimensional ◽  
Temporal Correlation ◽  
Model System ◽  
Collective Behaviour ◽  
Living Systems ◽  
Nearest Neighbour ◽  
Length Scales ◽  
Neighbour Distance

Collective behaviour in living systems is observed across many scales, from bacteria to insects, to fish shoals. Zebrafish have emerged as a model system amenable to laboratory study. Here we report a three-dimensional study of the collective dynamics of fifty zebrafish. We observed the emergence of collective behaviour changing between ordered to randomised, upon adaptation to new environmental conditions. We quantify the spatial and temporal correlation functions of the fish and identify two length scales, the persistence length and the nearest neighbour distance, that capture the essence of the behavioural changes. The ratio of the two length scales correlates robustly with the polarisation of collective motion that we explain with a reductionist model of self–propelled particles with alignment interactions.

Bounds on the mean power-weighted nearest neighbour distance

2008 ◽  
Vol 464 (2097) ◽  
pp. 2293-2301 ◽  
Author(s):  
Elia Liitiäinen ◽  
Amaury Lendasse ◽  
Francesco Corona
Keyword(s):  
Computational Geometry ◽  
Sample Size ◽  
Random Graphs ◽  
Statistical Physics ◽  
Nearest Neighbour ◽  
Mean Power ◽  
Neighbour Distance ◽  
Parametric Statistics ◽  
The Mean ◽  
Structure Of Matter

In this paper, bounds on the mean power-weighted nearest neighbour distance are derived. Previous work concentrates mainly on the infinite sample limit, whereas our bounds hold for any sample size. The results are expected to be of importance, for example in statistical physics, non-parametric statistics and computational geometry, where they are related to the structure of matter as well as properties of statistical estimators and random graphs.

Effects Of Mno-Doping On The Structure Of Sodium Metaphosphate Glasses

2003 ◽  
Vol 58 (7-8) ◽  
pp. 419-428 ◽  
Author(s):  
N. Zotov ◽  
H. Schlenz ◽  
B. Brendebacha ◽  
H. Modrowa ◽  
J. Hormesa ◽  
...  
Keyword(s):  
Glass Structure ◽  
Phosphate Glasses ◽  
Average Chain Length ◽  
Nearest Neighbour ◽  
X Ray Diffraction ◽  
Strong Decrease ◽  
Sodium Metaphosphate ◽  
Neighbour Distance ◽  
X Ray ◽  
The Mean

A combined structural study on ternary phosphate glasses (MnO)x(NaPO3)1−x, x = 0.0, 0.024, 0.048, 0.167, is performed using X-ray diffraction, EXAFS and Raman spectroscopy. The mean Mn-O nearest-neighbour distance and the Mn-O coordination number in the glass with 16.7 mol% MnO are 2.15(2) °A and 5.7±0.4, respectively. Depolymerization of the metaphosphate chains in the NaPO3 glass structure is observed with increasing MnO content by Raman scattering. This leads to a strong decrease of the average chain length and a small decreasing of the average P-O-P bridging angle with increasing MnO content.

scholarly journals Dominating Lengthscales of Zebrafish Collective Behaviour

2021 ◽  
Author(s):  
Yushi Yang ◽  
Francesco Turci ◽  
Erika Kague ◽  
Chrissy L. Hammond ◽  
John Russo ◽  
...  
Keyword(s):  
Collective Motion ◽  
Persistence Length ◽  
Three Dimensional ◽  
Temporal Correlation ◽  
Model System ◽  
Collective Behaviour ◽  
Living Systems ◽  
Nearest Neighbour ◽  
Length Scales ◽  
Neighbour Distance

AbstractCollective behaviour in living systems is observed across many scales, from bacteria to insects, to fish shoals. Zebrafish have emerged as a model system amenable to laboratory study. Here we report a three-dimensional study of the collective dynamics of fifty Zebrafish. We observed the emergence of collective behaviour changing between polarised to randomised, upon adaption to new environmental conditions. We quantify the spatial and temporal correlation functions of the fish and identify two length scales, the persistence length and the nearest neighbour distance, that capture the essence of the behavioural changes. The ratio of the two length scales correlates robustly with the polarisation of collective motion that we explain with a reductionist model of self–propelled particles with alignment interactions.

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

2002 ◽  
Vol 727 ◽  
Author(s):  
S. Ichikawa ◽  
T. Akita ◽  
M. Okumura ◽  
M. Haruta ◽  
K. Tanaka
Keyword(s):  
Contact Angle ◽  
Titanium Oxide ◽  
Gold Catalyst ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Electron Holography ◽  
Gold Particles ◽  
Oxide Support ◽  
The Mean ◽  
A Charge

AbstractThe catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

The Influence of Blade Wakes on the Performance of Interturbine Diffusers

1996 ◽  
Vol 118 (2) ◽  
pp. 347-352 ◽  
Author(s):  
R. G. Dominy ◽  
D. A. Kirkham
Keyword(s):  
Performance Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Two Dimensional ◽  
Correct Performance ◽  
Analysis Methods ◽  
Flow Factor ◽  
The Mean ◽  
Lp Turbine

Interturbine diffusers provide continuity between HP and LP turbines while diffusing the flow upstream of the LP turbine. Increasing the mean turbine diameter offers the potential advantage of reducing the flow factor in the following stages, leading to increased efficiency. The flows associated with these interturbine diffusers differ from those in simple annular diffusers both as a consequence of their high-curvature S-shaped geometry and of the presence of wakes created by the upstream turbine. It is shown that even the simplest two-dimensional wakes result in significantly modified flows through such ducts. These introduce strong secondary flows demonstrating that fully three-dimensional, viscous analysis methods are essential for correct performance modeling.

scholarly journals Proximity of the middle meningeal artery and maxillary artery to the mandibular head and mandibular neck as revealed by three-dimensional time-of-flight magnetic resonance angiography

2021 ◽  
Author(s):  
Daphne Schönegg ◽  
Raphael Ferrari ◽  
Julian Ebner ◽  
Michael Blumer ◽  
Martin Lanzer ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Three Dimensional ◽  
Time Of Flight ◽  
Middle Meningeal Artery ◽  
Individual Variability ◽  
Maxillary Artery ◽  
Condylar Process ◽  
The Mean ◽  
Meningeal Artery

Abstract Purpose The close topographic relationship between vascular and osseous structures in the condylar and subcondylar region and marked variability in the arterial course has been revealed by both imaging and cadaveric studies. This study aimed to verify the previously published information in a large sample and to determine a safe surgical region. Methods We analyzed the three-dimensional time-of-flight magnetic resonance angiography images of 300 individuals. Results The mean distance between the middle meningeal artery and the apex of the condyle or the most medial point of the condyle was 18.8 mm (range: 11.2–25.9 mm) or 14.5 mm (range: 8.8–22.9 mm) respectively. The course of the maxillary artery relative to the lateral pterygoid muscle was medial in 45.7% of cases and lateral in 54.3%. An asymmetric course was evident in 66 patients (22%). The mean distance between the maxillary artery and condylar process at the deepest point of the mandibular notch was 6.2 mm in sides exhibiting a medial course (range: 3.7–9.8 mm) and 6.6 mm in sides exhibiting a lateral course (range: 3.9–10.4 mm). The distances were significantly influenced by age, gender, and the course of the maxillary artery. Conclusion Our study emphasizes the marked inter- and intra-individual variability of the maxillary and middle meningeal arterial courses. We confirmed the proximity of the arteries to the condylar process. Extensive surgical experience and thorough preparation for each individual case are essential to prevent iatrogenic vascular injury.

scholarly journals Interactions between Tandem Cylinders in an Open Channel: Impact on Mean and Turbulent Flow Characteristics

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1718
Author(s):  
Hasan Zobeyer ◽  
Abul B. M. Baki ◽  
Saika Nowshin Nowrin
Keyword(s):  
Turbulent Flow ◽  
Open Channel ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Recirculation ◽  
Tandem Cylinders ◽  
Flow Development ◽  
The Mean ◽  
Recirculation Length

The flow hydrodynamics around a single cylinder differ significantly from the flow fields around two cylinders in a tandem or side-by-side arrangement. In this study, the experimental results on the mean and turbulence characteristics of flow generated by a pair of cylinders placed in tandem in an open-channel flume are presented. An acoustic Doppler velocimeter (ADV) was used to measure the instantaneous three-dimensional velocity components. This study investigated the effect of cylinder spacing at 3D, 6D, and 9D (center to center) distances on the mean and turbulent flow profiles and the distribution of near-bed shear stress behind the tandem cylinders in the plane of symmetry, where D is the cylinder diameter. The results revealed that the downstream cylinder influenced the flow development between cylinders (i.e., midstream) with 3D, 6D, and 9D spacing. However, the downstream cylinder controlled the flow recirculation length midstream for the 3D distance and showed zero interruption in the 6D and 9D distances. The peak of the turbulent metrics generally occurred near the end of the recirculation zone in all scenarios.

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