scholarly journals Anisotropic Composition and Mechanical Behavior of a Natural Thin-Walled Composite: Eagle Feather Shaft

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 309
Author(s):  
Siyu Cai ◽  
Baoshuai Han ◽  
Yanjin Xu ◽  
Enyu Guo ◽  
Bin Sun ◽  
...  

Flight feather shafts are outstanding bioinspiration templates due to their unique light weight and their stiff and strong characteristics. As a thin wall of a natural composite beam, the keratinous cortex has evolved anisotropic features to support flight. Here, the anisotropic keratin composition, tensile response, dynamic properties of the cortex, and fracture behaviors of the shafts are clarified. The analysis of Fourier transform infrared (FTIR) spectra indicates that the protein composition of calamus cortex is almost homogeneous. In the middle and distal shafts (rachis), the content of the hydrogen bonds (HBs) and side-chain is the highest within the dorsal cortex and is consistently lower within the lateral wall. The tensile responses, including the properties and dominant damage pattern, are correlated with keratin composition and fiber orientation in the cortex. As for dynamic properties, the storage modulus and damping of the cortex are also anisotropic, corresponding to variation in protein composition and fibrous structure. The fracture behaviors of bent shafts include matrix breakage, fiber dissociation and fiber rupture on compressive dorsal cortex. To clarify, ‘real-time’ damage behaviors, and an integrated analysis between AE signals and fracture morphologies, are performed, indicating that calamus failure results from a straight buckling crack and final fiber rupture. Moreover, in the dorsal and lateral walls of rachis, the matrix breakage initially occurs, and then the propagation of the crack is restrained by ‘ligament-like’ fiber bundles and cross fiber, respectively. Subsequently, the further matrix breakage, interface dissociation and induced fiber rupture in the dorsal cortex result in the final failure.

Author(s):  
Svitlana Sivitska

UDC 338:336.02:621.311 Svitlana Sivitska, Ph.D., Associate Professor at Finance and Banking Department, Vice-Rector for Scientific, Educational, Social Work and International Cooperation. Poltava National Technical Yuri Kondratyuk University. Identification of strategic priorities of investment into development of alternative energetics. There are the stages of the methodology for choosing the strategic priorities of investing in alternative energy explored in the article. The potential of alternative energy analyzed. The strategic priorities of alternative energy have been explored. An integrated analysis of the potential of alternative energy is carried out on the territorial basis done. The matrix of choice of strategic priorities of investing in alternative energy determined. Keywords: energetic security, alternative energetics, renewable sources of energy, investment, strategic priorities, matrix.


1993 ◽  
Vol 115 (3) ◽  
pp. 314-318 ◽  
Author(s):  
S. M. Spearing ◽  
F. W. Zok

A computer simulation of multiple cracking in fiber-reinforced brittle matrix composites has been conducted, with emphasis on the role of the matrix flaw distribution. The simulations incorporate the effect of bridging fibers on the stress required for cracking. Both short and long (steady-state) flaws are considered. Furthermore, the effects of crack interactions (through the overlap of interface slip lengths) are incorporated. The influence of the crack distribution on the tensile response of such composites is also examined.


2007 ◽  
Vol 81 (13) ◽  
pp. 7111-7123 ◽  
Author(s):  
Benjamin J. Chen ◽  
George P. Leser ◽  
Eiji Morita ◽  
Robert A. Lamb

ABSTRACT For influenza virus, we developed an efficient, noncytotoxic, plasmid-based virus-like particle (VLP) system to reflect authentic virus particles. This system was characterized biochemically by analysis of VLP protein composition, morphologically by electron microscopy, and functionally with a VLP infectivity assay. The VLP system was used to address the identity of the minimal set of viral proteins required for budding. Combinations of viral proteins were expressed in cells, and the polypeptide composition of the particles released into the culture media was analyzed. Contrary to previous findings in which matrix (M1) protein was considered to be the driving force of budding because M1 was found to be released copiously into the culture medium when M1 was expressed by using the vaccinia virus T7 RNA polymerase-driven overexpression system, in our noncytotoxic VLP system M1 was not released efficiently into the culture medium. Additionally, hemagglutinin (HA), when treated with exogenous neuraminidase (NA) or coexpressed with viral NA, could be released from cells independently of M1. Incorporation of M1 into VLPs required HA expression, although when M1 was omitted from VLPs, particles with morphologies similar to those of wild-type VLPs or viruses were observed. Furthermore, when HA and NA cytoplasmic tail mutants were included in the VLPs, M1 failed to be efficiently incorporated into VLPs, consistent with a model in which the glycoproteins control virus budding by sorting to lipid raft microdomains and recruiting the internal viral core components. VLP formation also occurred independently of the function of Vps4 in the multivesicular body pathway, as dominant-negative Vps4 proteins failed to inhibit influenza VLP budding.


1995 ◽  
Vol 42 (2) ◽  
pp. 205-210 ◽  
Author(s):  
P Widłak ◽  
J Rogoliński ◽  
J Rzeszowska-Wolny

Preincubation of rat liver nuclei with copper ions influenced the stability and protein composition of the nuclear matrices isolated by a "high salt" method. Also the specific interaction between matrix proteins and the kappa Ig matrix attachment region of DNA was affected.


1988 ◽  
Vol 90 (4) ◽  
pp. 621-628 ◽  
Author(s):  
W. Waitz ◽  
P. Loidl

A novel method for in situ preparation of nuclear matrix from whole plasmodia of Physarum polycephalum without isolation of nuclei is presented. Plasmodia are encapsulated in agarose beads and after solubilization of the cytoplasm the nuclear matrix is prepared. With this quick and easy technique nuclear matrix can be reproducibly prepared with perfect recovery. We compared the ultrastructural and biochemical properties of the matrix after three different matrix isolation procedures: preparation with high salt, ammonium sulphate and lithium diiodosalicylic acid. The results show that the ultrastructure and protein composition of the three types of matrix are very similar or even identical. We conclude that many of the conflicting results on nuclear matrix in the literature are due to perturbations of nuclear integrity during the isolation of nuclei. For this reason the new in situ method is an important approach in the standardization of nuclear matrix isolation.


2014 ◽  
Vol 501-504 ◽  
pp. 1888-1891 ◽  
Author(s):  
Cheng Lin Gong ◽  
Hua Liu ◽  
Jian Zhang

Intake tower is a complex structure, which has complex boundary conditions and has complex loading situation. Intake tower is made up of reinforced concrete ,which is thin-wall hollow structure. It builds in the near the shore in the reservoir, its top bridge connects to the banks of the river, The tower is in the water and is under pressure, intake towers safety is very important under the action of earthquake. Based on the large finite element software ANSYS, the dynamic properties of the intake tower is studied, and the intake tower+ foundation is also studied. The research conclusions can be used as reference for engineering design.


Author(s):  
Hui Tang ◽  
Yangmin Li ◽  
Jiming Huang

This article presents a novel design of a flexure-based, piezoelectric actuated, completely decoupled, high-bandwidth, highresolution, and large stroke parallel XY micromanipulator with two amplification levers. The monolithic mechanism is featured with dual working modes, which meets different kinds of requirements in terms of high resolution and large workspace in micro/nano fields. In order to reduce the displacement loss, the modeling and analysis of bending motion of the levers are conducted; thereafter, compliance and stiffness modeling by employing the matrix method are established. Furthermore, the dynamics modeling and analysis via Lagrange equations are performed to improve the dynamic properties of the mechanism. The simulation results of finite element analysis indicate that the cross-coupling between the two axes is kept to 1.2%; meanwhile, the natural frequency of the mechanism is about 700 Hz, and the amplifier ratio is approximately 2.32. Both theoretical analysis and finite element analysis results well validate the performance of the proposed mechanism.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Bao-Qing Pei ◽  
Hui Li ◽  
Gang Zhu ◽  
De-Yu Li ◽  
Yu-Bo Fan ◽  
...  

The intervertebral disc degeneration and injury are the most common spinal diseases with tremendous financial and social implications. Regenerative therapies for disc repair are promising treatments. Fiber-reinforced materials (FRMs) are a kind of composites by embedding the fibers into the matrix materials. FRMs can maintain the original properties of the matrix and enhance the mechanical properties. By now, there are still some problems for disc repair such as the unsatisfied static strength and dynamic properties for disc implants. The application of FRMs may resolve these problems to some extent. In this review, six parts such as background of FRMs in tissue repair, the comparison of mechanical properties between natural disc and some typical FRMs, the repair standard and FRMs applications in disc repair, and the possible research directions for FRMs' in the future are stated.


Cell ◽  
2003 ◽  
Vol 115 (5) ◽  
pp. 629-640 ◽  
Author(s):  
Vamsi K. Mootha ◽  
Jakob Bunkenborg ◽  
Jesper V. Olsen ◽  
Majbrit Hjerrild ◽  
Jacek R. Wisniewski ◽  
...  

2008 ◽  
Vol 41-42 ◽  
pp. 61-67
Author(s):  
Li Liang ◽  
Ming Li ◽  
Chi Tay Tsai

Dynamic properties of Nanostructured Metal Matrix Composites (NMMCs) materials consisting of nanograined aluminum matrix with nano or micro-sized ceramics particulates are calculated using Ansys/LS-DYNA in this paper. There are three conditions for the mechanics analysis involved the target with 10 vol. % SiC, 30 vol. % SiC and 50 vol. % SiC. It is assumed that the SiC particles uniformly distributed in the matrix. According to the analysis, the strength of NMMCs material is reduced, and the deformation of target is weakened by the vol. % of SiC increasing.


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