Capturing the influence of geometric variations on permeability using a numerical permeability prediction tool

2016 ◽  
Vol 35 (24) ◽  
pp. 1802-1813 ◽  
Author(s):  
Elinor E Swery ◽  
Tom Allen ◽  
Piaras Kelly
Keyword(s):  
Single Unit ◽  
Close Agreement ◽  
Single Layer ◽  
Prediction Tool ◽  
Number Of Layers ◽  
Unit Cells ◽  
Modelling Techniques ◽  
Woven Textile ◽  
Automated Tool ◽  
Textile Modelling

An automated tool has been developed for generation of permeability predictions for multi-layered unit cells utilising textile modelling techniques. This tool has been used to predict the permeability tensor of a woven textile. Single-layer predictions were carried out and the predicted permeabilities obtained were in close agreement to the permeability behaviour captured experimentally. The tool was used to capture the effects of textile variability on its permeability, isolating the influence of individual parameters. A complete textile sample was also analysed, predicting its permeability map. The concept of estimating the permeability of a textile with variability using an average single unit cell was explored. The prediction tool was also used to study the effect of preform structure on its permeability, including consideration of the number of layers, ply shift and applied compaction.

Plasmon modes in N-layer silicene structures

2021 ◽  
Author(s):  
Men Nguyen Van
Keyword(s):  
Electric Field ◽  
Random Phase ◽  
Single Layer ◽  
Plasmon Mode ◽  
Orbit Coupling ◽  
Collective Excitations ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Number Of Layers ◽  
Plasmon Modes

Abstract We investigate the plasmon properties in N-layer silicene systems consisting of N, up to 6, parallel single-layer silicene under the application of an out-of-plane electric field, taking into account the spin-orbit coupling within the random-phase approximation. Numerical calculations demonstrate that N undamped plasmon modes, including one in-phase optical and (N-1) out-of-phase acoustic modes, continue mainly outside the single-particle excitation area of the system. As the number of layers increases, the frequencies of plasmonic collective excitations increase and can become much larger than that in single layer silicene, more significant for high-frequency modes. The optical (acoustic) plasmon mode(s) noticeably (slightly) decreases with the increase in the bandgap and weakly depends on the number of layers. We observe that the phase transition of the system weakly affects the plasmon properties, and as the bandgap caused by the spin-orbit coupling equal that caused by the external electric field, the plasmonic collective excitations and their broadening function in multilayer silicene behave similarly to those in multilayer gapless graphene structures. Our investigations show that plasmon curves in the system move toward that in single layer silicene as the separation increases, and the impacts of this factor can be raised by a large number of layers in the system. Finally, we find that the imbalanced carrier density between silicene layers significantly decreases plasmon frequencies, depending on the number of layers.

Stacked Microchannel Heat Sinks for Liquid Cooling of Microelectronic Components

2000 ◽  
Author(s):  
X. Wei ◽  
Y. Joshi
Keyword(s):  
Flow Rate ◽  
Heat Sink ◽  
Water Flow Rate ◽  
Heat Removal ◽  
Single Layer ◽  
Heat Sinks ◽  
Computationally Efficient ◽  
Liquid Cooling ◽  
Number Of Layers ◽  
Microelectronic Components

Abstract A novel heat sink based on a multi-layer stack of liquid cooled microchannels is investigated. For a given pumping power and heat removal capability for the heat sink, the flow rate across a stack of microchannels is lower compared to a single layer of microchannels. Numerical simulations using a computationally efficient multigrid method [1] were carried out to investigate the detailed conjugate transport within the heat sink. The effects of the microchannel aspect ratio and total number of layers on thermal performance were studied for water as coolant. A heat sink of base area 10 mm by 10 mm with a height in the range 1.8 to 4.5 mm (2–5 layers) was considered with water flow rate in the range 0.83×10−6 m3/s (50 ml/min) to 6.67×10−6 m3/s (400 ml/min). The results of the computational simulations were also compared with a simplified thermal resistance network analysis.

An overview of deep learning techniques

2018 ◽  
Vol 66 (9) ◽  
pp. 690-703 ◽  
Author(s):  
Michael Vogt
Keyword(s):  
Deep Learning ◽  
Single Layer ◽  
Visual Image ◽  
Image Understanding ◽  
Number Of Layers ◽  
Box Models ◽  
Learning Techniques ◽  
Engineering Work ◽  
Computational Resources ◽  
Black Box Models

Abstract Deep learning is the paradigm that profoundly changed the artificial intelligence landscape within only a few years. Although accompanied by a variety of algorithmic achievements, this technology is disruptive mainly from the application perspective: It considerably pushes the border of tasks that can be automated, changes the way products are developed, and is available to virtually everyone. Subject of deep learning are artificial neural networks with a large number of layers. Compared to earlier approaches with ideally a single layer, this allows using massive computational resources to train black-box models directly on raw data with a minimum of engineering work. Most successful applications are found in visual image understanding, but also in audio and text modeling.

scholarly journals Synthesis of heterovalently substituted slab perovskites Sr2–xLnxBIV1–xBxIIIO4 (BIV= Sn, Ti, BIII= Sc, In)

2021 ◽  
pp. 77-83
Author(s):  
Y.A. Titov ◽  
◽  
M.S. Slobodyanik ◽  
V.V. Chumak ◽  
M.V. Tymoshenko ◽  
...  
Keyword(s):  
Layer Structure ◽  
Single Layer ◽  
Continuous Phase ◽  
Phase Region ◽  
Heterovalent Substitution ◽  
Linear Type ◽  
X Ray ◽  
Unit Cells ◽  
Pseudobinary Systems ◽  
New Compounds

The possibility of the heterovalent substitution of A- and B-positions atoms in a single-layer slab perovskite-like structure of strontium titanate and stannate Sr2BIVO4 (BIV= Ti, Sn) by type Sr2–xLnxBIV1–xBxIIIO4 (Ln == La – Tb, BIV= Ti, Sn, BIII= Sc, In) has been established by X-ray powder diffraction methods. The bounda-ries of the heterovalent substitution of A- and B-positions atoms and the crystallographic parameters of the synthesized Sr2–xLnxBIV1–xBxIIIO4 phases with a single-layer structure are determined. The continuous phase area formation with a single-layer structure has been observed in 10 systems: Sr2–xLnxTi1–xScxO4 (Ln = La, Pr, Nd, Sm, Eu), Sr2–xLnxTi1–xInxO4 (Ln = La, Pr), Sr2–xLaxSn1–xScxO4, Sr2–xLnxSn1–xInxO4 (Ln = La, Pr). In-creasing the degree of heterovalent substitution of atoms in these systems leads to a reduction of the sym metry of the crystal lattice of phases from the tetragonal (space group I4/mmm) to the interconnected rhombic one. In the rest of the studied Sr2–xLnxBIV1–xBxIIIO4 systems, the existence of a narrow (x value significantly less than 1) phase region with a single-layer structure based on Sr3BIVO7 is observed. The character of the phase relations in the Sr2–xLnxBIV1–xBxIIIO4 systems (Ln = La – Tb, BIII= Sc, In) (BIV= Sn, Ti) and the linear type of concentra-tion dependences of the parameters of the reduced tetragonal unit cells of Sr2–xLnxBIV1–xBxIIIO4 phases with a single-layer structure indicate that, by their nature, these phases are series of solid solutions in the pseudobinary systems Sr2BIVO4 – SrLnBIIIO4 (BIV= Ti, Sn, BIII = Sc, In). The obtained data can be used to regulate the functional properties of titanates and stannates Sr2BIVO4 and materials based on them, as well as to solve the problem of a purposeful search for new compounds of the type An+1BnO3n+1 with a slab perovskite-like structure.

In-plane Shear Measurements of Textile Composites with Large Unit Cells using the Plate Twist Test

2002 ◽  
Vol 10 (7) ◽  
pp. 511-520
Author(s):  
G. Weissenbach ◽  
D. Brown ◽  
L. Limmer
Keyword(s):  
Textile Composites ◽  
Test Method ◽  
Shear Behaviour ◽  
Specimen Preparation ◽  
Plane Shear ◽  
Test Fixture ◽  
Large Unit ◽  
Unit Cells ◽  
Set Up ◽  
Woven Textile

The application of the plate twist test method to 3D-woven textile composites was investigated using both numerical analyses of the test set-up as well as experimental results. Comparisons with the widely used V-notched beam shear and 10°-off-axis tension tests are introduced in an attempt to identify the true in-plane shear response. The results of this study demonstrate that with careful specimen preparation and an adequate test fixture precise in-plane shear modulus data can be obtained. Moreover, for 3D-woven textile composites with their large unit cells the plate twist test appears to be superior in revealing the “true” in-plane shear behaviour.

Consistent community detection in multi-layer network data

Biometrika ◽  
2019 ◽  
Vol 107 (1) ◽  
pp. 61-73 ◽  
Author(s):  
Jing Lei ◽  
Kehui Chen ◽  
Brian Lynch
Keyword(s):  
Community Detection ◽  
Single Layer ◽  
Edge Density ◽  
Network Data ◽  
Model Framework ◽  
Multiple Modalities ◽  
Stochastic Block Model ◽  
Number Of Layers ◽  
Consistency Results ◽  
Theoretical Results

Summary We consider multi-layer network data where the relationships between pairs of elements are reflected in multiple modalities, and may be described by multivariate or even high-dimensional vectors. Under the multi-layer stochastic block model framework we derive consistency results for a least squares estimation of memberships. Our theorems show that, as compared to single-layer community detection, a multi-layer network provides much richer information that allows for consistent community detection from a much sparser network, with required edge density reduced by a factor of the square root of the number of layers. Moreover, the multi-layer framework can detect cohesive community structure across layers, which might be hard to detect by any single-layer or simple aggregation. Simulations and a data example are provided to support the theoretical results.

scholarly journals Preliminary Study of the Significance of Reverberation by IVUS Detection for Patients With Severe Calcified Lesions

2021 ◽  
Author(s):  
Wei You ◽  
Hong-li Zhang ◽  
Tian Xu ◽  
Pei-na Meng ◽  
Yu-he Zhou ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Multivariate Logistic Regression Analysis ◽  
Single Layer ◽  
Double Layers ◽  
Observational Point ◽  
Number Of Layers ◽  
Inner Surface ◽  
Preliminary Study ◽  
The Relationship ◽  
Calcified Coronary Lesions

Abstract Objectives―To explore the potential significance of the reverberation of calcification by comparing both intravascular ultrasound (IVUS) and optical coherence tomography (OCT) measurement post manual coregistration.Background―The reverberation phenomenon is often detected by IVUS for severe calcified lesions post rotational atherectomy (RA), which is thought to be due to the glassy and smooth inner surfaces of calcifications. Because of the poor penetration of IVUS, it is impossible to measure the thickness of calcifications, and the relationship between multiple reverberations and the thickness of calcification lesions has not been reported before.Methods―A total of forty-nine patients with severe calcified coronary lesions that were detected by IVUS and OCT simultaneously were enrolled in our retrospective study. If reverberation phenomena were detected by IVUS, intravascular imaging (IVI) data (including distance between the IVUS catheter center and the inner surface of the reverberation signal, the intervals between all adjacent reverberation signals, the number of layers of reverberation in IVUS, and the thickness of the calcification in OCT) were measured at the same position and same direction (each cross-section had 4 mutually perpendicular directions) at 1-mm intervals. If the observational point (direction) had a reverberation signal, it was an effective observational point that would be enrolled in our study; otherwise, it would be regarded as an invalid observational point and excluded from this study. The correlation between each reverberation observational value and OCT data was the primary target in this retrospective study. Results―Four hundred twenty-eight valid observational points were analyzed simultaneously by IVUS and OCT; among them, 300 points had a single layer of reverberation, 83 had double layers of reverberation and 42 had multiple layers (≥3 layers) of reverberation by IVUS detection post-RA. Multivariate logistic regression analysis showed that the number of layers of reverberation by IVUS was significantly related to the thickness of calcifications by OCT at the same point and in the same direction (p<0.001). Single, double, and multiple layers of reverberation in IVUS correspond to median calcification thicknesses (interquartile ranges (IQRs)) of 0.620 mm (0.520–0.720), 0.950 mm (0.840–1.040) and 1.185 mm (1.068–1.373), respectively, by OCT detection. No correlation was found between the distance between the IVI catheter center and the inner surface of the reverberation signal or the interval between every adjacent reverberation signal and the thickness of the calcification.Conclusions―The number of layers of reverberation signal detected by IVUS is positively correlated with the thickness of calcifications measured by OCT post-RA.

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