scholarly journals Development and Testing of Woven FRP Flexure Hinges for Pressure-Actuated Cellular Structures with Regard to Morphing Wing Applications

Aerospace ◽  
2019 ◽  
Vol 6 (11) ◽  
pp. 116
Author(s):  
Patrick Meyer ◽  
Johannes Boblenz ◽  
Cornelia Sennewald ◽  
Michael Vorhof ◽  
Christian Hühne ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Cellular Structures ◽  
High Lift ◽  
Reinforced Plastics ◽  
Flexure Hinges ◽  
Key Factor ◽  
Potential Applications ◽  
Fiber Reinforced Plastics ◽  
The One ◽  
External Forces

Shape-variable structures can change their geometry in a targeted way and thus adapt their outer shape to different operating conditions. The potential applications in aviation are manifold and far-reaching. The substitution of conventional flaps in high-lift systems or even the deformation of entire wing profiles is conceivable. All morphing approaches have to deal with the same challenge: A conflict between minimizing actuating forces on the one hand, and maximizing structural deflections and resistance to external forces on the other. A promising concept of shape variability to face this challenging conflict is found in biology. Pressure-actuated cellular structures (PACS) are based on the movement of nastic plants. Firstly, a brief review of the holistic design approach of PACS is presented. The aim of the following study is to investigate manufacturing possibilities for woven flexure hinges in closed cellular structures. Weaving trials are first performed on the material level and finally on a five-cell PACS cantilever. The overall feasibility of woven fiber reinforced plastics (FRP)-PACS is proven. However, the results show that the materials selection in the weaving process substantially influences the mechanical behavior of flexure hinges. Thus, the optimization of manufacturing parameters is a key factor for the realization of woven FRP-PACS.

Influence of sliding bearing design on efficiency of the fluoroplast macromodifier for antifriction carbon plastics

2021 ◽  
pp. 65-75
Author(s):  
I. V. Lishevich ◽  
A. V. Anisimov ◽  
G. I. Nikolaev ◽  
A. S. Savelov ◽  
A. S. Sargsyan
Keyword(s):  
Sliding Friction ◽  
Friction Unit ◽  
Sliding Bearings ◽  
Friction Zone ◽  
Reinforced Plastics ◽  
Friction Units ◽  
Carbon Plastics ◽  
Key Factor ◽  
Fiber Reinforced Plastics ◽  
Bearing Design

The paper presents the results of laboratory and bench tests of UGET and FUT antifriction carbon plastics macro modified with PTFE. The efficiency (friction coefficient reduction) of this modification of carbon fiber reinforced plastics has been confirmed. The dependence of the method’s efficiency on the design of sliding friction units has been established. The plastic deformation of the fluoroplastic is the key factor that determines the effectiveness of the modifier when designing sliding bearings. The design of the friction unit should exclude the pressure gradient in the fluoroplastic protectors and prevent the possibility of an uncontrolled exit of the fluoroplastic from the friction zone.

OnPoint: A package for online experiments in motor control and motor learning

2020 ◽  
Author(s):  
Jonathan Sanching Tsay ◽  
Alan S. Lee ◽  
Guy Avraham ◽  
Darius E. Parvin ◽  
Jeremy Ho ◽  
...  
Keyword(s):  
Motor Control ◽  
Motor Learning ◽  
Open Source Software ◽  
Research Progress ◽  
Global Pandemic ◽  
Large N ◽  
Open Source Software Package ◽  
Potential Applications ◽  
Temporal And Spatial ◽  
The One

Motor learning experiments are typically run in-person, exploiting finely calibrated setups (digitizing tablets, robotic manipulandum, full VR displays) that provide high temporal and spatial resolution. However, these experiments come at a cost, not limited to the one-time expense of purchasing equipment but also the substantial time devoted to recruiting participants and administering the experiment. Moreover, exceptional circumstances that limit in-person testing, such as a global pandemic, may halt research progress. These limitations of in-person motor learning research have motivated the design of OnPoint, an open-source software package for motor control and motor learning researchers. As with all online studies, OnPoint offers an opportunity to conduct large-N motor learning studies, with potential applications to do faster pilot testing, replicate previous findings, and conduct longitudinal studies (GitHub repository: https://github.com/alan-s-lee/OnPoint).

High-temperature carbon plastics based on thermoreactive polyimide binder

2020 ◽  
pp. 89-102
Author(s):  
M. I. Valueva ◽  
I. V. Zelenina ◽  
M. A. Zharinov ◽  
M. A. Khaskov
Keyword(s):  
Glass Transition ◽  
High Temperature ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Strength Properties ◽  
High Glass Transition Temperature ◽  
Reinforced Plastics ◽  
Carbon Plastics ◽  
Fundamental Possibility ◽  
Fiber Reinforced Plastics

The article presents results of studies of experimental carbon plastics based on thermosetting PMRpolyimide binder. Сarbon fiber reinforced plastics (CFRPs) are made from prepregs prepared by melt and mortar technologies, so the rheological properties of the polyimide binder were investigated. The heat resistance of carbon plastics was researched and its elastic-strength characteristics were determined at temperatures up to 320°С. The fundamental possibility of manufacturing carbon fiber from prepregs based on polyimide binder, obtained both by melt and mortar technologies, is shown. CFRPs made from two types of prepregs have a high glass transition temperature: 364°C (melt) and 367°C (solution), with this temperature remaining at the 97% level after boiling, and also at approximately the same (86–97%) level of conservation of elastic strength properties at temperature 300°С.

Effect of long climatic ageing on the microstructure of the surface of сarbon-fiber-reinforced plastics on base epoxy matrix

2019 ◽  
pp. 157-169 ◽  
Author(s):  
I. S. Deev ◽  
E. V. Kurshev ◽  
S. L. Lonsky
Keyword(s):  
Climatic Factors ◽  
Temperate Climate ◽  
Fiber Reinforced ◽  
Humid Climate ◽  
Climatic Zones ◽  
Reinforced Plastics ◽  
Carbon Plastics ◽  
Fiber Reinforced Plastics ◽  
Determining Factor

Studies and experimental data on the microstructure of the surface of samples of epoxy сarbon-fiber-reinforced plastics that have undergone long-term (up to 5 years) climatic aging in different climatic zones of Russia have been conducted: under conditions of the industrial zone of temperate climate (Moscow, MTsKI); temperate warm climate (Gelendzhik, GTsKI); a warm humid climate (Sochi, GNIP RAS). It is established that the determining factor for aging of carbon plastics is the duration of the complex effect of climatic factors: the longer the period of climatic aging, the more significant changes occur in the microstructure of the surface of the materials. The intensity of the aging process and the degree of microstructural changes in the surface of carbon plastics are affected by the features of the climatic zone. general regularities and features of the destruction of the surface of carbon plastics after a long-term exposure to climatic factors have been established on the basis of the analysis and systematization of the results of microstructural studies.

Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria

2011 ◽  
Vol 57 (7) ◽  
pp. 606-610 ◽  
Author(s):  
Rumyana Eneva ◽  
Stephan Engibarov ◽  
Tanya Strateva ◽  
Radoslav Abrashev ◽  
Ignat Abrashev
Keyword(s):  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Environmental Isolates ◽  
Anaerobic Conditions ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Cholera Vibrio ◽  
Key Factor ◽  
Aeration Conditions ◽  
The One

Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera — Vibrio cholerae О1 — is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6–5.8.

scholarly journals Topological guided-mode resonances at non-Hermitian nanophotonic interfaces

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ki Young Lee ◽  
Kwang Wook Yoo ◽  
Youngsun Choi ◽  
Gunpyo Kim ◽  
Sangmo Cheon ◽  
...  
Keyword(s):  
Fundamental Study ◽  
One Dimensional ◽  
Guided Mode ◽  
Wall Structures ◽  
Potential Applications ◽  
Photonic Microstructures ◽  
Guided Mode Resonance ◽  
The One ◽  
Photonic Band ◽  
Topological Correlations

Abstract The topological properties of photonic microstructures are of great interest because of their experimental feasibility for fundamental study and potential applications. Here, we show that robust guided-mode-resonance states exist in photonic domain-wall structures whenever the complex photonic band structures involve certain topological correlations in general. Using the non-Hermitian photonic analogy of the one-dimensional Dirac equation, we derive essential conditions for photonic Jackiw-Rebbi-state resonances taking advantage of unique spatial confinement and spot-like spectral features which are remarkably robust against random parametric errors. Therefore, the proposed resonance configuration potentially provides a powerful method to create compact and stable photonic resonators for various applications in practice.

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