scholarly journals Theoretical analyses of mechanical performance of higher-order vertex-based hierarchical square cell structure subjected to compression

2019 ◽  
Vol 1213 ◽  
pp. 052116
Author(s):  
Chong Shi ◽  
Zhonggang Wang
Keyword(s):  
Mechanical Performance ◽  
Cell Structure ◽  
Higher Order ◽  
Theoretical Analyses ◽  
Square Cell

Theoretical Analyses of the Universal Approximation Capability of a Class of Higher Order Neural Networks Based on Approximate Identity

2016 ◽  
pp. 1456-1470 ◽  
Author(s):  
Saeed Panahian Fard ◽  
Zarita Zainuddin
Keyword(s):  
Neural Networks ◽  
Approximation Theory ◽  
Special Class ◽  
Higher Order ◽  
Approximate Identity ◽  
Universal Approximation ◽  
Multivariate Functions ◽  
Higher Order Neural Networks ◽  
Approximation Capability ◽  
Theoretical Analyses

One of the most important problems in the theory of approximation functions by means of neural networks is universal approximation capability of neural networks. In this study, we investigate the theoretical analyses of the universal approximation capability of a special class of three layer feedforward higher order neural networks based on the concept of approximate identity in the space of continuous multivariate functions. Moreover, we present theoretical analyses of the universal approximation capability of the networks in the spaces of Lebesgue integrable multivariate functions. The methods used in proving our results are based on the concepts of convolution and epsilon-net. The obtained results can be seen as an attempt towards the development of approximation theory by means of neural networks.

scholarly journals Variation of Mechanical Characteristics of Polyurethane Foam: Effect of Test Method

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2672 ◽  
Author(s):  
Ki-Beom Park ◽  
Hee-Tae Kim ◽  
Nam-Yong Her ◽  
Jae-Myung Lee
Keyword(s):  
Polyurethane Foam ◽  
Evaluation Method ◽  
Mechanical Performance ◽  
Cell Structure ◽  
Extreme Environments ◽  
Evaluation Criteria ◽  
Test Method ◽  
Material Behavior ◽  
Insulation Material ◽  
Binding Effect

Polyurethane foam (PUF), a representative insulation material, not only prevents heat conduction but can also support a load. Particular interest in rigid PUF proliferated over the past several years in fields where extreme environments are applied. A closed-cell structure which forms the interior of rigid PUF serves to maximize the utilization of these polymeric foams. Rigid PUF is more sensitive to external conditions such as temperature or restraint than other structural materials such as steel. Depending on the market trends in which utilization of a cryogenic environment is expanding, the tendency of material behavior resulting from the binding effect also needs to be investigated. However, most conventional compression test method standards applicable to rigid PUF do not adequately reflect the restraints. Therefore, this study proposes a method for evaluating the mechanical performance of materials in a more reliable manner than that of conventional tests. Experimental observation and analysis validated this compression evaluation method in which constraints are considered. Consequently, the compressive strength of rigid PUF compared to the results of the conventional test showed a difference of up to 0.47 MPa (approximately 23%) at cryogenic temperatures. This result suggests that there are important factors to consider when assessing performance from a material perspective in an environment where rigid PUF insulation is utilized. It is believed that the test methods newly proposed in this study will provide an experimental framework that can be applied to the evaluation criteria of material properties and reflected in structural design.

Manufacture of Ultra-Dense Knitted Superelastic Structures

2018 ◽  
Author(s):  
Henry Koon ◽  
Jack Laven ◽  
Julianna Abel
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Cell Structure ◽  
Axial Loading ◽  
Consumer Products ◽  
Niti Shape Memory Alloy ◽  
Structural Element ◽  
Loading Tests ◽  
Structural Architecture ◽  
The Impact

Knitted Textiles made from Nickel-Titanium (NiTi) shape memory alloy wires are a new structural element with enhanced properties for a variety of applications. Potential advantages of this structural form include enhanced bending flexibility, tailorable in-plane, and through-thickness mechanical performance, and energy absorption and damping. Inspection of the knit pattern reveals a repeating cell structure of interlocking loops. Because of this repeating structure, knits can be evaluated as cellular structures that leverage their loop-based architecture for mechanical robustness and flexibility. The flexibility and robustness of the structure can be further enhanced by manufacturing with superelastic NiTi. The stiffness of superelastic NiTi, however, makes traditional knit manufacturing techniques inadequate, so knit manufacturing in this research is aided by shape setting the superelastic wire to a predefined pattern mimicking the natural curve of a strand within a knit fabric. This predefined shape-set geometry determines the outcome of the knit’s mechanical performance and tunes the mechanical properties. In this research, the impact of the shape setting process on the material itself is explored through axial loading tests to quantify the effect that heat treatment has on a knit sample. A means of continuously shape setting and feeding the wire into traditional knitting machines is described. These processes lend themselves to mass production and build upon previous textile manufacturing technologies. This research also proposes an empirical exploration of superelastic NiTi knit mechanical performance and several new techniques for manufacturing such knits with adjustable knit parameters. Displacement-controlled axial loading tests in the vertical (wale) direction determined the recoverability of each knit sample in the research and were iteratively increased until failure resulted. Knit samples showed recoverable axial strains of 65–140%, which could be moderately altered based on knit pattern and loop parameters. Furthermore, this research demonstrates that improving the density of the knit increases the stiffness of the knit without any loss in recoverable strains. These results highlight the potential of this unique structural architecture that could be used to design fabrics with adjustable mechanical properties, expanding the design space for aerospace structures, medical devices, and consumer products.

scholarly journals CRISPR/Cas9 Genome Editing Technology: A Valuable Tool for Understanding Plant Cell Wall Biosynthesis and Function

2020 ◽  
Vol 11 ◽  
Author(s):  
Yuan Zhang ◽  
Allan M. Showalter
Keyword(s):  
Cell Wall ◽  
Genome Editing ◽  
Gene Targeting ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Cell Structure ◽  
Higher Order ◽  
Knock Out ◽  
Genetic Crossing ◽  
And Function

For the past 5 years, clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technology has appeared in the molecular biology research spotlight. As a game-changing player in genome editing, CRISPR/Cas9 technology has revolutionized animal research, including medical research and human gene therapy as well as plant science research, particularly for crop improvement. One of the most common applications of CRISPR/Cas9 is to generate genetic knock-out mutants. Recently, several multiplex genome editing approaches utilizing CRISPR/Cas9 were developed and applied in various aspects of plant research. Here we summarize these approaches as they relate to plants, particularly with respect to understanding the biosynthesis and function of the plant cell wall. The plant cell wall is a polysaccharide-rich cell structure that is vital to plant cell formation, growth, and development. Humans are heavily dependent on the byproducts of the plant cell wall such as shelter, food, clothes, and fuel. Genes involved in the assembly of the plant cell wall are often highly redundant. To identify these redundant genes, higher-order knock-out mutants need to be generated, which is conventionally done by genetic crossing. Compared with genetic crossing, CRISPR/Cas9 multi-gene targeting can greatly shorten the process of higher-order mutant generation and screening, which is especially useful to characterize cell wall related genes in plant species that require longer growth time. Moreover, CRISPR/Cas9 makes it possible to knock out genes when null T-DNA mutants are not available or are genetically linked. Because of these advantages, CRISPR/Cas9 is becoming an ideal and indispensable tool to perform functional studies in plant cell wall research. In this review, we provide perspectives on how to design CRISPR/Cas9 to achieve efficient gene editing and multi-gene targeting in plants. We also discuss the recent development of the virus-based CRISPR/Cas9 system and the application of CRISPR/Cas9 to knock in genes. Lastly, we summarized current progress on using CRISPR/Cas9 for the characterization of plant cell wall-related genes.

Control of the cell structure of microcellular silicone rubber/nanographite foam for enhanced mechanical performance

2017 ◽  
Vol 133 ◽  
pp. 288-298 ◽  
Author(s):  
Jianwei Bai ◽  
Xia Liao ◽  
Erbo Huang ◽  
Yong Luo ◽  
Qi Yang ◽  
...  
Keyword(s):  
Silicone Rubber ◽  
Mechanical Performance ◽  
Cell Structure

Theoretical Analyses of the Universal Approximation Capability of a class of Higher Order Neural Networks based on Approximate Identity

2016 ◽  
pp. 192-207
Author(s):  
Saeed Panahian ◽  
Zarita Zainuddin
Keyword(s):  
Neural Networks ◽  
Approximation Theory ◽  
Special Class ◽  
Higher Order ◽  
Approximate Identity ◽  
Universal Approximation ◽  
Multivariate Functions ◽  
Higher Order Neural Networks ◽  
Approximation Capability ◽  
Theoretical Analyses

One of the most important problems in the theory of approximation functions by means of neural networks is universal approximation capability of neural networks. In this study, we investigate the theoretical analyses of the universal approximation capability of a special class of three layer feedforward higher order neural networks based on the concept of approximate identity in the space of continuous multivariate functions. Moreover, we present theoretical analyses of the universal approximation capability of the networks in the spaces of Lebesgue integrable multivariate functions. The methods used in proving our results are based on the concepts of convolution and epsilon-net. The obtained results can be seen as an attempt towards the development of approximation theory by means of neural networks.

scholarly journals The Role of Foaming Agent and Processing Route in Mechanical Performance of Fabricated Aluminum Foams

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Alexandra Byakova ◽  
Iegor Kartuzov ◽  
Svyatoslav Gnyloskurenko ◽  
Takashi Nakamura
Keyword(s):  
Cell Wall ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Cell Structure ◽  
Wall Material ◽  
Processing Route ◽  
Foaming Agent ◽  
Closed Cell ◽  
Al Foams

The results of this study highlight the role of foaming agent and processing route in influencing the contamination of cell wall material by side products, which, in turn, affects the macroscopic mechanical response of closed-cell Al-foams. Several kinds of Al-foams have been produced with pure Al/Al-alloys by the Alporas like melt process, all performed with and without Ca additive and processed either with conventional TiH2foaming agent or CaCO3as an alternative one. Damage behavior of contaminations was believed to affect the micromechanism of foam deformation, favoring either plastic buckling or brittle failure of cell walls. No discrepancy between experimental values of compressive strengths for Al-foams comprising ductile cell wall constituents and those prescribed by theoretical models for closed-cell structure was found while the presence of low ductile and/or brittle eutectic domains and contaminations including particles/layers of Al3Ti, residues of partially reacted TiH2, and Ca bearing compounds, results in reducing the compressive strength to values close to or even below those of open-cell foams of the same relative density.

Mechanical performance of vertex-based hierarchical vs square thin-walled multi-cell structure

2019 ◽  
Vol 134 ◽  
pp. 102-110 ◽  
Author(s):  
Zhonggang Wang ◽  
Zhendong Li ◽  
Chong Shi ◽  
Wei Zhou
Keyword(s):  
Mechanical Performance ◽  
Cell Structure ◽  
Thin Walled
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