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Influence of plywood grain direction on sandwich panel bending properties  [PDF]
Jaroslav Kljak,Mladen Brezovi?,Alan Antonovi?
Drvna Industrija , 2009,
Abstract: This paper investigates the influence of plywood grain direction on bending properties of a sandwich panel, as well as on stress distribution in each layer. Experimental sandwich panels (tnom= 29 mm) were made of two three-ply plywood panels and a rigid PVC core between them. Grain directions of plywood panels were between 0° and 90°, continuously raised by 15°. Seven models of sandwich panels were made. Bending properties of a sandwich panel was determined by three point bending method and stress in each layer was determined by using finite element method. Simulation models were developed with equal load conditions as applied during empirical measurement of bending properties of the sandwich panel. The research results show that grain direction has a great influence on bending properties of the sandwich panel, as well as on stress values in each layer. Results also indicate the importance of analyzing stress in each layer of plywood for the purpose of avoiding stress concentration in respective layers and for optimizing structural construction of the sandwich panel. Such stress analyses are not covered by standardized empirical methods for determining bending properties of sandwich panels.
Photomechanical Energy Conversion of Photoresponsive Fibers Exhibiting Bending Behavior  [PDF]
Kazuya Nakata,Yosuke Ishikawa,Munetoshi Sakai,Baoshun Liu,Tsuyoshi Ochiai,Hideki Sakai,Taketoshi Murakami,Masahiko Abe,Akira Fujishima
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/574124
Abstract: Photoresponsive fibers based on poly(acrylamide) (PAA) with methylene blue (MB) dye were prepared. All semicircular fibers show bending towards the direction of the flat surface of the fiber when illuminated. The fibers recover their initial shape when the illumination stops. The fiber is heated upon illumination and cooled to room temperature once the illumination is stopped. The fiber also is sensitive to humidity, showing bending behavior towards the direction of the flat surface of the fiber upon changing the humidity. The mechanical energy of the PAA/MB fiber is approximately 0.6?mN for the bending direction when it is illuminated. A possible mechanism for the bending behavior is as follow: (1) the fiber is heated upon illumination because of the photothermal effect, (2) the fiber loses water molecules, (3) the fiber shrinks; bending towards the direction of the flat surface of the fiber occurs because of a difference in the shrinkage for the flat surface and the other side of the fiber. Finally, we demonstrated that a PP ball (1.5?mg) can be moved by the mechanical energy produced by the changing shape of the fiber upon illumination. 1. Introduction Utilization of solar energy is a key factor for development of a sustainable society. Among a number of approaches for solar energy conversion, photomechanical energy conversion has significant advantages such as direct energy conversion from photo to mechanical, which may potentially lead to high energy conversion efficiency, no cable for working, and space-saving. Typical photomechanical materials that change shape in response to light are liquid crystalline elastomer films based on azobenzene derivatives [1–14]. These materials show bending behavior upon illumination because the structure of azobenzene derivative molecules in the film changes from trans to cis form, which generates mechanical energy. Although these materials have attracted much attention because they can be applied as photodriven motors [9], actuators [1, 3, 4, 6, 8, 10, 11, 15–17], and new types of solar energy conversion systems [2, 5, 7, 11–14, 16, 18, 19], they need multiple synthetic procedures followed by rubbing to align the azobenzene molecules, which makes them impractical for many applications. Materials exhibiting a volume change in response to light are of interest [20–22]. For example, hydrogels that show a volume change upon the application of light have been reported previously [21–23]. The basic mechanism for the volume change is a solvent absorption/desorption process. Suzuki and Tanaka reported that a polymer gel
Electrospinning of aligned fibers with adjustable orientation using auxiliary electrodes  [cached]
Matthias M L Arras, Christian Grasl, Helga Bergmeister and Heinrich Schima
Science and Technology of Advanced Materials , 2012,
Abstract: A conventional electrospinning setup was upgraded by two turnable plate-like auxiliary high-voltage electrodes that allowed aligned fiber deposition in adjustable directions. Fiber morphology was analyzed by scanning electron microscopy and attenuated total reflection Fourier transform infrared spectroscopy (FTIR-ATR). The auxiliary electric field constrained the jet bending instability and the fiber deposition became controllable. At target speeds of 0.9 m s 1 90% of the fibers had aligned within 2°, whereas the angular spread was 70° without the use of auxiliary electrodes. It was even possible to orient fibers perpendicular to the rotational direction of the target. The fiber diameter became smaller and its distribution narrower, while according to the FTIR-ATR measurement the molecular orientation of the polymer was unaltered. This study comprehensively documents the feasibility of directed fiber deposition and offers an easy upgrade to existing electrospinning setups.
Photomechanical Bending of Azobenzene-Based Photochromic Molecular Fibers  [PDF]
Hideyuki Nakano,Ryoji Ichikawa,Riku Matsui
Micromachines , 2013, DOI: 10.3390/mi4020128
Abstract: Microfibers composed of azobenzene-based photochromic amorphous molecular materials, namely low molecular-mass photochromic materials with a glass-forming property, could be fabricated. These fibers were found to exhibit mechanical bending motion upon irradiation with a laser beam. In addition, the bending direction could be controlled by altering the polarization direction of the irradiated light without changing the position of the light source or the wavelength of the light. In-situ fluorescence observation of mass transport induced at the surface of the fiber doped with CdSe quantum dots suggested that the bending motions were related with the photoinduced mass transport taking place near the irradiated surface of the fiber.
Singular fibers of the bending flows on the moduli space of 3D polygons  [PDF]
Damien Bouloc
Mathematics , 2015,
Abstract: In this paper, we prove that in the system of bending flows on the moduli space of polygons with fixed side lengths introduced by Kapovich and Millson, the singular fibers are isotropic homogeneous submanifolds. The proof covers the case where the system is defined by any maximal family of disjoint diagonals. We also take in account the case where the fixed side lengths are not generic. In this case, the phase space is an orbispace, and our result holds in the sense that singular fibers are isotropic orbispaces.
SEM in situ laboratory investigations on damage growth in GFRP composite under three-point bending tests
HongWei Zhou,L. Mishnaevsky Jr,P. Br ndsted,JinBiao Tan,LeLe Gui
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-009-0560-1
Abstract: Glass fiber-reinforced polymer (GFRP) composites are widely used in low-weight constructions. SEM (scanning electron microscopy) in situ experiments of damage growth in GFRP composite under three-point bending loads are carried out. By summarizing the experimental results of three groups of samples with different orientation angles of fibers, the dependence of mechanical parameters on the orientation angles of fibers are analyzed. The regression analysis show that the peak strengths, the elastic strengths and the elastic modulus of the composites decease with the orientation angles of fibers almost linearly. Moreover, the damage growth and meso-scale structure changes in GFRP composites during three-point bending loading are analyzed.
SEM in situ laboratory investigations on damage growth in GFRP composite under three-point bending tests

ZHOU HongWei,MISHNAEVSKY Jr L,BR ,NDSTED P,TAN JinBiao &,GUI LeLe,

科学通报(英文版) , 2010,
Abstract: Glass fiber-reinforced polymer (GFRP) composites are widely used in low-weight constructions.SEM (scanning electron microscopy) in situ experiments of damage growth in GFRP composite under three-point bending loads are carried out.By summarizing the experimental results of three groups of samples with different orientation angles of fibers,the dependence of mechanical parameters on the orientation angles of fibers are analyzed.The regression analysis show that the peak strengths,the elastic strengths and th...
Magnetic and Inertial Orientation Tracking for Inserting Humans into Networked Synthetic Environment
SuthanthiraVanitha N.,M. Mani,V. Palanisamy
International Journal of Soft Computing , 2012,
Abstract: This study demonstrates the new technology that overcomes the limitations of motion tracking technologies currently in use. The technology is capable of providing wide area tracking of multiple users for synthetic environment and augment reality applications. This system makes a significant step toward total immersion of users in a networked synthetic environment by allowing them to interface with it using their natural bodies. Orientation can be determined without the aid of a generated source using nine axis Magnetic, Angular Rate and Gravity sensor unit containing three orthogonally mounted angular rate sensors, three orthogonal accelerometers and three orthogonal magnetometers. Primarily this study involves the development of a prototype MARG Sensors tracking system including innovative calibration and angle tracking software. An examination of this implementation demonstrates the feasibility of a hybrid motion tracking system for networked synthetic environments. Mathematical analysis, a computer simulation and physical experiments are used to validate the correctness of the complementary filter algorithm as well as human body model. Experimental results show the effectiveness of the tracking system.
MECHANICAL PROPERTIES OF COMPOSITE MATERIAL REINFORCING BY NATURAL-SYNTHETIC FIBERS  [PDF]
Ali I. Al-Mosawi,Mohammad H.Al-Maamori,Zaynab A.Wetwet
Academic Research International , 2012,
Abstract: The mechanical properties of araldite matrix composites reinforced with hybrid palms - kevlar fibers were evaluated. There are indications that the incorporation of both fibers into a singlematrix which is araldite resin will stabilize mechanical properties and lowering manufacturing costs. In this research the impact strength, tensile strength, flexural strength, and hardnesswere studied for composite material reinforced with hybrid fibers for palms and Kevlar .These fibers were mixed with araldite resin in different reinforcement percentage (20%, 40%, and 60%) and the effect on the above mechanical properties were studied. It has shown animprovement in these mechanical properties after reinforcement by fibers the value of mechanical properties will increase with increasing percentage of reinforcement.
Stretching Induces the Rearrangement of the Periodontal Ligament Cells without Altering the Orientation of Oxytalan Fibers Relative to the Cell Axis in Vitro  [PDF]
Sachio Tamaoki, Kazuki Nakashima, Yoshinori Yamauchi, Kaori Yamanouchi, Takahiro Fujita, Eichi Tsuruga, Hiroyuki Ishikawa
Open Journal of Stomatology (OJST) , 2016, DOI: 10.4236/ojst.2016.612031
Abstract: The periodontal ligament (PDL) contains oxytalan fibers as well as collagen fibers, which helps it to withstand the mechanical stress to which it is constantly exposed. The oxytalan fibers are produced by PDL fibroblasts. However, the arrangement of PDL fibroblasts and the orientation of oxytalan fibers relative to the fibroblast cell axis have not been investigated under the condition of mechanical stress. We hypothesized that such stress would alter the arrangement and orientation of these cells and their oxytalan fibers. The aim of this study was to evaluate the effects of stretching strain on PDL fibroblasts, focusing on the cellular arrangement and orientation of oxytalan fibers relative to the long cell axis in cell/matrix layers by staining the major component of the fibers, fibrillin-1. The angle between the long cell axis and the oxytalan fibers was approximately 70 degrees under both non-stretching and stretching conditions. Moreover, stretching induced the rearrangement of the cells. This is the first study to demonstrate that stretching induces the rearrangement of the PDL fibroblasts without altering the angle between the long cell axis and the oxytalan fibers. These results may reflect the orientation of oxytalan fibers in the PDL under the condition of mechanical stress.
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