Yhe Compression Meso-Mechanics Theoretical Model and Experimental Verification of Polyurethane-Based Warp-Knit Spacer Fabric Composites

2021 ◽  
Vol 8 (5) ◽  
pp. 30-38
Author(s):  
Si Chen
Keyword(s):  
Theoretical Model ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Beam Theory ◽  
Theoretical Research ◽  
Dimensional Structure ◽  
Static Compression ◽  
Theoretical Simulation ◽  
Winkler Elastic Foundation ◽  
Spacer Fabric

In this research, a new type of binary material, a polyurethane-based warp-knitted spacer fabric composite (PWSF), having a unique three-dimensional structure, high strength, and a variety of surface structures was prepared. The compression meso-mechanics theoretical model based on the Winkler elastic foundation beam theory and structural parameters of PWSF were used to predict the compression performance of PWSF. To verify the validity of compression model, the compression stress-strain curves of theoretical simulation were compared with the quasi-static compression test results. The deviation between these two compression moduli was less than 7%. The compression meso-mechanics model established in this study can effectively simulate the actual compression behaviors for different PWSF specimens. A regular pattern of compression properties of this novel composite from the theoretical research on meso-mechanics perspectives can be proposed.

scholarly journals Brain capillary structures of schizophrenia cases and controls show a correlation with their neuron structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rino Saiga ◽  
Masayuki Uesugi ◽  
Akihisa Takeuchi ◽  
Kentaro Uesugi ◽  
Yoshio Suzuki ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Superior Temporal Gyrus ◽  
Anterior Cingulate ◽  
Dimensional Structure ◽  
Constant Diameter ◽  
The Mean ◽  
Cartesian Coordinate ◽  
Micrometer Scale

AbstractBrain blood vessels constitute a micrometer-scale vascular network responsible for supply of oxygen and nutrition. In this study, we analyzed cerebral tissues of the anterior cingulate cortex and superior temporal gyrus of schizophrenia cases and age/gender-matched controls by using synchrotron radiation microtomography or micro-CT in order to examine the three-dimensional structure of cerebral vessels. Over 1 m of cerebral blood vessels was traced to build Cartesian-coordinate models, which were then used for calculating structural parameters including the diameter and curvature of the vessels. The distribution of vessel outer diameters showed a peak at 7–9 μm, corresponding to the diameter of the capillaries. Mean curvatures of the capillary vessels showed a significant correlation to the mean curvatures of neurites, while the mean capillary diameter was almost constant, independent of the cases. Our previous studies indicated that the neurites of schizophrenia cases are thin and tortuous compared to controls. The curved capillaries with a constant diameter should occupy a nearly constant volume, while neurons suffering from neurite thinning should have reduced volumes, resulting in a volumetric imbalance between the neurons and the vessels. We suggest that the observed structural correlation between neurons and blood vessels is related to neurovascular abnormalities in schizophrenia.

scholarly journals Seventeen-Armed Star Polystyrenes in Various Molecular Weights: Structural Details and Chain Characteristics

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1894
Author(s):  
Jia Chyi Wong ◽  
Li Xiang ◽  
Kuan Hoon Ngoi ◽  
Chin Hua Chia ◽  
Kyeong Sik Jin ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Star Polymers ◽  
Star Polymer ◽  
Dimensional Structure ◽  
Density Profiles ◽  
Molecular Weights ◽  
Radiation Sources ◽  
Structural Details

Star-shaped polymers are very attractive because of their potential application ability in various technological areas due to their unique molecular topology. Thus, information on the molecular structure and chain characteristics of star polymers is essential for gaining insights into their properties and finding better applications. In this study, we report molecular structure details and chain characteristics of 17-armed polystyrenes in various molecular weights: 17-Arm(2k)-PS, 17-Arm(6k)-PS, 17-Arm(10k)-PS, and 17-Arm(20k)-PS. Quantitative X-ray scattering analysis using synchrotron radiation sources was conducted for this series of star polymers in two different solvents (cyclohexane and tetrahydrofuran), providing a comprehensive set of three-dimensional structure parameters, including radial density profiles and chain characteristics. Some of the structural parameters were crosschecked by qualitative scattering analysis and dynamic light scattering. They all were found to have ellipsoidal shapes consisting of a core and a fuzzy shell; such ellipse nature is originated from the dendritic core. In particular, the fraction of the fuzzy shell part enabling to store desired chemicals or agents was confirmed to be exceptionally high in cyclohexane, ranging from 74 to 81%; higher-molecular-weight star polymer gives a larger fraction of the fuzzy shell. The largest fraction (81%) of the fuzzy shell was significantly reduced to 52% in tetrahydrofuran; in contrast, the lowest fraction (19%) of core was increased to 48%. These selective shell contraction and core expansion can be useful as a key mechanism in various applications. Overall, the 17-armed polystyrenes of this study are suitable for applications in various technological fields including smart deliveries of drugs, genes, biomedical imaging agents, and other desired chemicals.

Three-Dimensional Structure Trajectory Guiding Scan and Points Cloud Registration

2013 ◽  
Vol 300-301 ◽  
pp. 423-426
Author(s):  
Yong Cai
Keyword(s):  
Point Cloud ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Surface Model ◽  
Visual Measurement ◽  
Local Point ◽  
Inverse Kinematics Problem ◽  
The Relationship ◽  
Measurement Approach

Three-dimensional visual scanning is an advanced non-contact measurement approach that can obtain a complete surface model of object. But, in the method, the local raster point cloud sets calculated must be registered to a whole. To reduce fluctuating errors and increase efficiency, we propose a new method that scanner can be moved around object guided by pre-planning trajectory of the robot. First, considering the structural parameters of the robot, the Inverse Kinematics Problem of each joint rotating function is derived, and the moving trajectory is simulated. Then, the relationship between the distances of controlled motion and data gotten by scanner is analyzed, a transform matrix which registered the local point cloud sets is deduced, the raster data can be normalized to the world coordinate by it. The experimental results show that error of registration is less than 0.09mm. The method is suited to measuring different targets in robot workspace. It can improve the efficiency and flexibility of visual measurement system.

Simulation of plate compression behavior of warp-knitted spacer fabrics based on geometry and property parameters

2018 ◽  
Vol 89 (6) ◽  
pp. 1051-1064 ◽  
Author(s):  
Fengxin Sun ◽  
Mingying Ma ◽  
Xingxing Pan ◽  
Gui Liu ◽  
Shu Yang ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Strain Curve ◽  
Dimensional Structure ◽  
Bending Angle ◽  
Compression Behavior ◽  
Compression Property ◽  
Spacer Fabric ◽  
Spacer Fabrics

The plate compression property of warp-knitted spacer fabrics greatly determines their industrial application in cushions and mattresses, which can be regulated by the structure and property of spacer filaments of spacer fabrics. To better meet application requirements, this paper detailed a study on the relationships between the geometry and property parameters of spacer filaments and the plate compression property of spacer fabrics. A three-dimensional structure model was firstly developed using the finite element method based on a typical spacer fabric. The model shows a satisfactory prediction of the compression force–strain curve of the spacer fabric compared with the corresponding experimental curve. Consequently, the effects of geometry parameters, including height, diameter, arrangement density and bending angle of spacer filaments, and Young’s modulus of the filaments on the compression behavior of spacer fabrics were investigated using the validated model by adjusting the corresponding geometry and property parameters. The stress nephogram and stress distribution along the filaments at compression strain 0.6 were analyzed to discover the deformation mechanism of spacer filaments under compression. It was found that the spacer fabric with smaller filament height, courser filament diameter, larger bending angle, higher arrangement density and Young’s modulus of filaments had higher compression resistance. This study is useful to optimize the performance of spacer fabrics in design and manufacturing by purposefully tuning the geometry and property parameters.

scholarly journals Splayed Tetrahymena cilia. A system for analyzing sliding and axonemal spoke arrangements.

1976 ◽  
Vol 71 (2) ◽  
pp. 589-605 ◽  
Author(s):  
W S Sale ◽  
P Satir
Keyword(s):  
Structural Parameters ◽  
Three Dimensional ◽  
Tetrahymena Pyriformis ◽  
Dimensional Structure ◽  
Ciliary Movement ◽  
Dimensional Changes ◽  
Local Contraction ◽  
Critical Point Drying ◽  
Triton X ◽  
Section Analysis

This study makes use of a procedure designed to illustrate, without serial section analysis, the three-dimensional changes in the ciliary axoneme produced by microtubule sliding, and to confirm essential features of the sliding microtubule hypothesis of ciliary movement. Cilia, isolated from Tetrahymena pyriformis by the dibucaine procedure, are attached to polylysine substratum, and treated with Triton X-100. Critical point drying maintains three-dimensional structure without embedding. The detergent removes the membrane and many axonemes unroll, always in an organized fashion so that doublets follow one another in sequence, according to the enantiomorphic form of the cilium. The central pair of microtubules fall to the side as a unit. The parallel doublet microtubules retain relative longitudinal positions in part by interdoublet or nexin links. Spoke organization and tip patterns are preserved in the opened axonemes. We generalize the work of Warner and Satir (Warner, F. D., and P. Satir, 1976. J. Cell Biol. 63:35-63) to show that spoke group arrangements are maintained for all doublets in straight regions, while systematic displacements occur in bent regions. The conclusion that local contraction of microtubles is absent in the axoneme is strengthened, and direct graphic demonstrations of sliding at the ciliary tip are shown. A morphogenetic numbering scheme is presented which results in a quantitative fit of the tip images to the images predicated by the equation for doublet sliding, and which makes possible new comparisons of structural parameters between axonemes and with cilia of other organisms.

Visual Function: A Theoretical Model for Individuals with Low Vision

1983 ◽  
Vol 77 (8) ◽  
pp. 373-377 ◽  
Author(s):  
Anne L. Corn
Keyword(s):  
Theoretical Model ◽  
Visual Function ◽  
Low Vision ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Environmental Cues ◽  
Three Dimensional Structure ◽  
Visual Behaviors ◽  
Past Experiences ◽  
Available Resources

One's ability to function visually is determined by many factors. A theoretical model is proposed that organizes these factors into a pliable three-dimensional structure composed of visual abilities, available resources and past experiences, and environmental cues. Professionals can use the model to postulate how to elicit visual behaviors or to maximize visual function in individuals with low vision.

scholarly journals Warp-Knitted Spacer Fabric Reinforced Syntactic Foam: A Compression Modulus Meso-Mechanics Theoretical Model and Experimental Verification

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 286 ◽  
Author(s):  
Chao Zhi ◽  
Mingjuan Du ◽  
Zhaoling Sun ◽  
Mengjie Wu ◽  
Xiaoyi He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Theoretical Model ◽  
Volume Fraction ◽  
Syntactic Foam ◽  
Compression Modulus ◽  
Static Compression ◽  
Model Compression ◽  
Equivalent Inclusion Method ◽  
Spacer Fabric ◽  
New Type

In this study, a new type ternary composite, called warp-knitted spacer fabric reinforced syntactic foam (WKSF-SF), with the advantages of high mechanical properties and a lower density, was proposed. Then, a meso-mechanics theoretical model based on the Eshelby–Mori–Tanaka equivalent inclusion method, average stress method and composite hybrid theory was established to predict the compression modulus of WKSF-SF. In order to verify the validity of this model, compression modulus values of theoretical simulations were compared with the quasi-static compression experiment results. The results showed that the addition of suitable WKSF produces at least 15% improvement in the compressive modulus of WKSF-SF compared with neat syntactic foam (NSF). Meanwhile, the theoretical model can effectively simulate the values and variation tendency of the compression modulus for different WKSF-SF samples, and is especially suitable for the samples with smaller wall thickness or a moderate volume fraction of microballoons (the deviations is less than 5%). The study of the meso-mechanical properties of WKSF-SF will help to increase understanding of the compression properties of this new type composite deeply. It is expected that WKSF-SF can be used in aerospace, marine, transportation, construction, and other fields.

scholarly journals Crystal structure and Hirshfeld surface analysis of two (E)-N′-(para-substituted benzylidene) 4-chlorobenzenesulfonohydrazides

2018 ◽  
Vol 74 (12) ◽  
pp. 1808-1814
Author(s):  
Akshatha R. Salian ◽  
Sabine Foro ◽  
B. Thimme Gowda
Keyword(s):  
Hydrogen Bonds ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Hirshfeld Surface ◽  
Dimensional Structure ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Torsion Angles ◽  
Π Interactions ◽  
Compound Ii

Two (E)-N′-(p-substituted benzylidene)-4-chlorobenzenesulfonohydrazides, namely, (E)-4-chloro-N′-(4-chlorobenzylidene)benzenesulfonohydrazide, C13H10Cl2N2O2S, (I), and (E)-4-chloro-N′-(4-nitrobenzylidene)benzenesulfonohydrazide, C13H10ClN3O4S, (II), have been synthesized, characterized and their crystal structures studied to explore the effect of the nature of substituents on the structural parameters. Compound (II) crystallized with two independent molecules [(IIA) and IIB)] in the asymmetric unit. In both compounds, the configuration around the C=N bond is E. The molecules are twisted at the S atom with C—S—N—N torsion angles of −62.4 (2)° in (I), and −46.8 (2)° and 56.8 (2)° in the molecules A and B of (II). The 4-chlorophenylsulfonyl and 4-substituted benzylidene rings form dihedral angles of 81.0 (1)° in (I), 75.9 (1)° in (IIA) and 73.4 (1)° in (IIB). In the crystal of (I), molecules are linked via pairs of N—H...O hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif. The dimers are linked by C—Cl...π interactions, forming a three-dimensional structure. In the crystal of (II), molecules are linked by C—H...π interactions and N—H...O hydrogen bonds, forming –A–B–A–B– chains along the c-axis direction. The chains are linked via C—H...O and C—H...π interactions, forming layers parallel to the bc plane. Two-dimensional fingerprint plots show that the most significant contacts contributing to the Hirshfeld surface for (I) are H...H contacts (26.6%), followed by Cl...H/H...Cl (21.3%), O...H/H...O (15.5%) and Cl...C/C...Cl (10.7%), while for (II) the O...H/H...O contacts are dominant, with a contribution of 34.8%, followed by H...H (15.2%), C...H/H...C (14.0%) and Cl...H/H...Cl (10.0%) contacts.

scholarly journals A NEW TEST METHOD TO MEASURE THE COMPRESSIBILITY OF SPACER FABRICS

2019 ◽  
Vol 2019 ◽  
pp. 140-143
Author(s):  
Musa KILIC ◽  
Gonca BALCI KILIC ◽  
Murat DEMIR ◽  
Gulsah CELIK ◽  
Izzet Onal BUGDUZ ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Three Dimensional ◽  
Test System ◽  
Test Methods ◽  
Test Method ◽  
Dimensional Structure ◽  
Spacer Fabric ◽  
The Difference ◽  
Spacer Fabrics ◽  
Fabric Structures

Spacer fabric is a three-dimensional structure that obtained by the connection of two parallel fabric surfaces with the connection threads. Spacer fabrics are widely used for their several functional advantages that they provide unlike conventional fabrics. Compressibility is one of the important functional parameters for these fabric structures. The compressibility values of the spacer fabrics are measured based on the ISO 3386-1 standard. However, this standard is used for structures that have non-axial shear during compression such as foam, sponge and so on. It is thought that this standard is not suitable for spacer fabric structures due to the shear deformation which occurs during the measurement of compressibility. For this purpose, as in accordance with spacer fabrics end-use area, a new test system been proposed to measure of compressibility that prevents shear during the test. Thus, it is aimed to prevent the shear deformation and the deviant results obtained during the test. Within the scope of the study, the compressibility properties of spacer fabric structures, which have undergone different thicknesses and different finishing processes, were measured according to both ISO 3386-1 and the new proposed test method. When the results were compared, it was observed that the results obtained in the new proposed test setup were higher and the difference between the measured results according to both test methods was statistically significant for α = 0.05.

Sign in / Sign up

Export Citation Format

Share Document