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Michael I. Friswell - One of the best experts on this subject based on the ideXlab platform.

  • Multi-scale finite element model for a new material inspired by the mechanics and structure of wood cell-walls
    Journal of The Mechanics and Physics of Solids, 2012
    Co-Authors: Erick I. Saavedra Flores, Michael I. Friswell
    Abstract:

    Abstract This paper proposes a fully coupled multi-scale finite element model for the constitutive description of an alumina/magnesium Alloy/epoxy composite inspired in the mechanics and structure of the wall of wood cells. The mechanical response of the composite (the large scale continuum) is described by means of a representative volume element (RVE, corresponding to the intermediate scale) in which the Fibre is represented as a periodic alternation of alumina and magnesium Alloy fractions. Furthermore, at a lower scale the overall constitutive behavior of the alumina/magnesium Alloy Fibre is modelled as a single material defined by a large number of RVEs (the smallest material scale) at the Gauss point (intermediate) level. Numerical material tests show that this new composite maximises its toughness when the hierarchical design of wood cellulose Fibres is replicated. The above results provide for the first time new clues into the understanding of how trees and plants optimise their microstructures at the cellulose level in order to absorb a large amount of strain energy before failure. These findings are likely to shed more light into natural materials and bio-inspired design strategies, which are still not well-understood at present.

  • Multi-scale finite element model for a new material inspired by the mechanics and structure of wood cell-walls
    Journal of the Mechanics and Physics of Solids, 2012
    Co-Authors: E. I. Saavedra Flores, Michael I. Friswell
    Abstract:

    This paper proposes a fully coupled multi-scale finite element model for the constitutive description of an alumina/magnesium Alloy/epoxy composite inspired in the mechanics and structure of the wall of wood cells. The mechanical response of the composite (the large scale continuum) is described by means of a representative volume element (RVE, corresponding to the intermediate scale) in which the Fibre is represented as a periodic alternation of alumina and magnesium Alloy fractions. Furthermore, at a lower scale the overall constitutive behavior of the alumina/magnesium Alloy Fibre is modelled as a single material defined by a large number of RVEs (the smallest material scale) at the Gauss point (intermediate) level. Numerical material tests show that this new composite maximises its toughness when the hierarchical design of wood cellulose Fibres is replicated. The above results provide for the first time new clues into the understanding of how trees and plants optimise their microstructures at the cellulose level in order to absorb a large amount of strain energy before failure. These findings are likely to shed more light into natural materials and bio-inspired design strategies, which are still not well-understood at present. ?? 2012 Elsevier Ltd.

  • Fully Coupled Three-Scale Finite Element Model for the Mechanical Response of a New Bio-Inspired Composite
    ASME 2011 Conference on Smart Materials Adaptive Structures and Intelligent Systems Volume 2, 2011
    Co-Authors: Erick I. Saavedra Flores, Michael I. Friswell, Senthil Murugan, Eduardo A. De Souza Neto
    Abstract:

    This paper proposes a fully coupled three-scale finite element model for the mechanical description of an alumina/magnesium Alloy/epoxy composite inspired in the mechanics and architecture of wood cellulose Fibres. The constitutive response of the composite (the large scale continuum) is described by means of a representative volume element (RVE, corresponding to the intermediate scale) in which the Fibre is represented as a periodic alternation of alumina and magnesium Alloy fractions. Furthermore, at a lower scale the overall constitutive behavior of the alumina/magnesium Alloy Fibre is modelled as a single material defined by a large number of RVEs (the smallest material scale) at the Gauss point (intermediate) level. Numerical material tests show that the choice of the volume fraction of alumina based on those volume fractions of crystalline cellulose found in wood cells results in a maximisation of toughness in the present bio-inspired composite.Copyright © 2011 by ASME

Y. Shiraishi - One of the best experts on this subject based on the ideXlab platform.

  • Development of an Artificial Myocardium using a Covalent Shape-memory Alloy Fiber and its Cardiovascular Diagnostic Response.
    Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2020
    Co-Authors: Y. Shiraishi, T. Yambe, K. Sekine, Y. Saijo, Q. Wang, S. Nitta, S. Konno, N. Masumoto, J. Nagatoshi
    Abstract:

    The authors have been developing a newly-designed totally-implantable artificial myocardium using a covalent shape-memory Alloy Fibre (Biometal®, Toki Corporation), which is attached onto the ventricular wall and is also capable of supporting the natural ventricular contraction. This mechanical system consists of a contraction assistive device, which is made of Ti-Ni Alloy. And the phenomenon of the martensitic transformation of the Alloy was employed to achieve the physiologic motion of the device. The diameter of the Alloy wire could be selected from 45 to 250μm. In this study, the basic characteristics of the fiber of 150μm was examined to design the sophisticated mechano-electric myocardium. The stress generated by the fiber was 400gf under the pulsatile driving condition (0.4W, 1Hz). Therefore it was indicated that the effective assistance might be achieved by using the Biometal shape-memory Alloy fiber.

  • Assessment of synchronization measures for effective ventricular support by using the shape memory Alloy Fibred artificial myocardium in goats
    2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009
    Co-Authors: Y. Shiraishi, Akira Tanaka, F. Sato, T. K. Sugai, Y. Sato, T. Yambe, Y. Saijo, M. Yoshizawa, Y. Kaneko, M. Uematsu
    Abstract:

    Thromboembolic and haemorrhagic complications are the primary causes of mortality and morbidity in patients with artificial hearts, which are known to be induced by the interactions between blood flow and artificial material surfaces. The authors have been developing a new mechanical artificial myocardial assist device by using a sophisticated shape memory Alloy Fibre in order to achieve the mechanical cardiac support from outside of the heart without a direct blood contacting surface. The original material employed as the actuator of artificial myocardial assist devices was 100 um Fibred-shaped, which was composed of covalent and metallic bonding structure and designed to generate 4-7 % shortening by Joule heating induced by the electric current input. In this study, we focused on the synchronization of the actuator with native cardiac function, and the phase delay parameter was examined in animal experiments using Saanen goats. Total weight of the device including the actuator was around 150 g, and the electric power was supplied transcutaneously. The device could be successfully installed into thoracic cavity, which was able to be girdling the left ventricle. The contraction of the device could be controlled by the originally designed microcomputer. The mechanical contraction signal input had been transmitted with the phase delay of 50-200 msec after the R-wave of ECG, and hemodynamic changes were investigated. Cardiac output and systolic left ventricular pressure were elevated with 20% delay of cardiac cycle by 27% and 7%, respectively, although there was smaller difference under the condition of the delay of over 30%. Therefore, it was suggested that the synchronization measures should be examined in order to achieve sophisticated ventricular passive/active support on physiological demand.

  • Morphological Approach for the Functional Improvement of an Artificial Myocardial Assist Device using Shape Memory Alloy Fibres
    2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
    Co-Authors: Y. Shiraishi, Daisuke Ogawa, Akira Tanaka, F. Sato, M. Yoshizawa, T. Yambe, Y. Saijo, Y. Wada, S. Itoh, R. Sakata
    Abstract:

    The authors have been developing a mechano-electric artificial myocardial assist system (artificial myocardium) which is capable of supporting natural contractile functions from the outside of the ventricle without blood contacting surface. In this study, a nano-tech covalent type shape memory Alloy Fibre (Biometal, Toki Corp, Japan) was employed and the parallel-link structured myocardial assist device was developed. And basic characteristics of the system were examined in a mechanical circulatory system as well as in animal experiments using goats. The contractile functions were evaluated with the mock circulatory system that simulated systemic circulation with a silicone left ventricular model and an aortic afterload. Hemodynamic performance was also examined in goats. Prior to the measurement, the artificial myocardial assist device was installed into the goat's thoracic cavity and attached onto the ventricular wall. As a result, the system could be installed successfully without severe complications related to the heating, and the aortic flow rate was increased by 15% and the systolic left ventricular pressure was elevated by 7% under the cardiac output condition of 3L/min in a goat. And those values were elevated by the improvement of the design which was capable of the natural morphological myocardial tissue streamlines. Therefore it was indicated that the effective assistance might be achieved by the contraction by the newly-designed artificial myocardial assist system using Biometal. Moreover it was suggested that the assistance gain might be obtained by the optimised configuration design along with the natural anatomical myocardial stream line.

  • Development of an Artificial Myocardium using a Covalent Shape-memory Alloy Fiber and its Cardiovascular Diagnostic Response
    2005 IEEE Engineering in Medicine and Biology 27th Annual Conference, 2006
    Co-Authors: Y. Shiraishi, T. Yambe, K. Sekine, Y. Saijo, Q. Wang, H. Liu, S. Nitta, S. Konno, N. Masumoto, J. Nagatoshi
    Abstract:

    The authors have been developing a newly-designed totally-implantable artificial myocardium using a covalent shape-memory Alloy Fibre (Biometalreg, Toki Corporation), which is attached onto the ventricular wall and is also capable of supporting the natural ventricular contraction. This mechanical system consists of a contraction assistive device, which is made of Ti-Ni Alloy. And the phenomenon of the martensitic transformation of the Alloy was employed to achieve the physiologic motion of the device. The diameter of the Alloy wire could be selected from 45 to 250 mum. In this study, the basic characteristics of the fiber of 150 mum was examined to design the sophisticated mechano-electric myocardium. The stress generated by the fiber was 400 gf under the pulsatile driving condition (0.4W, 1 Hz). Therefore it was indicated that the effective assistance might be achieved by using the Biometal shape-memory Alloy fiber

Bingcheng Li - One of the best experts on this subject based on the ideXlab platform.

M F Alpendurada - One of the best experts on this subject based on the ideXlab platform.

  • new developments in the analysis of fragrances and earthy musty compounds in water by solid phase microextraction metal Alloy Fibre coupled with gas chromatography tandem mass spectrometry
    Talanta, 2011
    Co-Authors: S Machado, Carlos Goncalves, Edite Cunha, A Guimaraes, M F Alpendurada
    Abstract:

    Fragrances are widespread aquatic contaminants due to their presence in many personal care products used daily in developed countries. Levels of galaxolide and tonalide are commonly found in surface waters, urban wastewaters and river sediments. On the other hand, earthy–musty compounds confer bad odour to drinking water at levels that challenge the analytical capabilities. The combined determination of earthy–musty compounds and fragrances in water would be a breakthrough to make the traditional organoleptic evaluation of the water quality stricter and safer for the analyst. Two approaches were attempted to improve the analytical capabilities: analyte pre-concentration with a newly developed PDMS-DVB solid-phase microextraction Fibre on metal Alloy core and sensitive detection by tandem mass spectrometry (MS/MS). The optimization of SPME parameters was carried out using a central composite design and desirability functions. The final optimum extraction conditions were: headspace extraction at 70 °C during 40 min adding 200 g L−1 of NaCl. The detection limits in tandem MS (0.02–20 ng L−1) were marginally lower compared to full scan except for geosmin and trichloroanisol which go down to 0.1 and 0.02 ng L−1, respectively. The analysis of different water matrices revealed that fragrances and earthy–musty compounds were absent from ground- and drinking waters. Surface waters of river Leca contained levels of galaxolide around 250 ng L−1 in the 4 terminal sampling stations, which are downstream of WWTPs and polluted tributaries. Geosmine was ubiquitously distributed in natural waters similarly in rivers Leca and Douro at concentrations <7 ng L−1.

  • New developments in the analysis of fragrances and earthy―musty compounds in water by solid-phase microextraction (metal Alloy Fibre) coupled with gas chromatography―(tandem) mass spectrometry
    Talanta, 2011
    Co-Authors: S Machado, Carlos Goncalves, Edite Cunha, A Guimaraes, M F Alpendurada
    Abstract:

    Fragrances are widespread aquatic contaminants due to their presence in many personal care products used daily in developed countries. Levels of galaxolide and tonalide are commonly found in surface waters, urban wastewaters and river sediments. On the other hand, earthy–musty compounds confer bad odour to drinking water at levels that challenge the analytical capabilities. The combined determination of earthy–musty compounds and fragrances in water would be a breakthrough to make the traditional organoleptic evaluation of the water quality stricter and safer for the analyst. Two approaches were attempted to improve the analytical capabilities: analyte pre-concentration with a newly developed PDMS-DVB solid-phase microextraction Fibre on metal Alloy core and sensitive detection by tandem mass spectrometry (MS/MS). The optimization of SPME parameters was carried out using a central composite design and desirability functions. The final optimum extraction conditions were: headspace extraction at 70 °C during 40 min adding 200 g L−1 of NaCl. The detection limits in tandem MS (0.02–20 ng L−1) were marginally lower compared to full scan except for geosmin and trichloroanisol which go down to 0.1 and 0.02 ng L−1, respectively. The analysis of different water matrices revealed that fragrances and earthy–musty compounds were absent from ground- and drinking waters. Surface waters of river Leca contained levels of galaxolide around 250 ng L−1 in the 4 terminal sampling stations, which are downstream of WWTPs and polluted tributaries. Geosmine was ubiquitously distributed in natural waters similarly in rivers Leca and Douro at concentrations

Akira Tanaka - One of the best experts on this subject based on the ideXlab platform.

  • Preliminary Studyonthefunctional reproduction ofanArtificial Myocardium using Covalent ShapeMemoryAlloy Fibre BasedonControl Engineering Yasuyuki Shiraishil, Tomoyuki Yambel, Kazumitsu Sekinel, Yoshifumi Saijol,
    2020
    Co-Authors: Satoshi Konnol, Shin-ichi Nitta, Qingtian Wang, Daisuke Ogawa, Akira Tanaka, Yasuyuki Kakubari, Hidekazu, Fumihiro Sato, Hidetoshi Matsuki
    Abstract:

    Theauthors havebeendeveloping anartificial myocardium using asophisticated covalent shape memory Alloy Fibre, whichiscapable ofassisting natural cardiac contraction fromtheoutside oftheventricular wall. Weapplied engineering method based onrobotics control andconstructed theartificial myocardial assist system whichmight be able toregulate derangement andregenerative tensile force onthesurface ofheart. Inthis study, adesign tosurround thetotal heart hasbeenestablished inorder torefrain fromthestress concentration bythemechanical assistance, and thehemodynamic performance oftheartificial myocardial assist system wereexamined inamockcirculatory system as wellasonanimal experiments using goats. Basic characteristics oftheshape memoryAlloy Fibre unit wereexamined andthedisplacement control could beachieved under thecondition ofthedifferent external temperature byfeedback using thePIDcontrol. Andalsotheincrease oftheexternal workofthegoats left ventricular pressure-volume relationship wereobtained bytheassistance using anartificial myocardium withparallel-linked configuration, and therefore itwasindicated that theeffective ventricular mechanical support could beperformed bythedevice.

  • Preliminary Study on Interactive Control for the Artificial Myocardium by Shape Memory Alloy Fibre
    IFMBE Proceedings, 2009
    Co-Authors: R. Sakata, Yasuyuki Shiraishi, Tomoyuki Yambe, Yoshifumi Saijo, M. Yoshizawa, Y. Sato, D. Jung, A. Baba, Akira Tanaka
    Abstract:

    The authors have been developing a sophisticated artificial myocardium for the treatment of heart failure, which is capable of supporting contractile function from the outside of the ventricle. The purpose of this study was to construct the control methodology of functional assistance by an artificial myocardium using small active mechanical elements composed of shape memory Alloy Fibres (Biometal). In order to achieve a sophisticated mechanical support by using shape memory Alloy Fibres, the diameter of which was 100 microns, the mechanical response of the myocardial assist device unit was examined by using PID (Proportional-Integral-Derivative) control method. Prior to the evaluation of dynamic characteristics, the relationship between strain and electric resistance of the shape memory Alloy Fibre and also the inditial response of each unit were obtained in the electrical bridge circuit. The component for the PID control was designed for the regulation of the myocardial contractile function. An originally-designed RISC microcomputer was employed and the input or output signals were controlled by pulse width modulation method in respect of displacement controls. Consequently, the optimal PID parameters were confirmed and the fibrous displacement was successfully regulated under the different heat transfer conditions simulating internal body temperature as well as bias tensile loading. Then it was indicated that this control methodology could be useful for more sophisticated ventricular passive or active restraint by using the artificial myocardium on physiological demand interactively.

  • First Trial of the Chronic Animal Examination of the Artificial Myocardial Function
    IFMBE Proceedings, 2009
    Co-Authors: Yasuyuki Shiraishi, Tomoyuki Yambe, Yoshifumi Saijo, Satoshi Konno, Akira Tanaka, K. Matsue, Muneichi Shibata, Telma Keiko Sugai, H. Song
    Abstract:

    Thromboembolic and haemorrhagic complications are the primary causes of mortality and morbidity in patients with artificial hearts, which are known to be induced by the interactions between blood flow and artificial material surfaces. The authors have been developing a new mechanical artificial myocardial assist device by using a sophisticated shape memory Alloy Fibre in order to achieve the mechanical cardiac support from outside of the heart without a direct blood contacting surface. The original material employed as the actuator of artificial myocardial assist devices was 100um Fibred-shaped, which was composed of covalent and metallic bonding structure and designed to generate 4–7 % shortening by Joule heating induced by the electric current input. Prior to the experiment, the myocardial streamlines were investigated by using a MDCT, and the design of artificial myocardial assist devices were refined based on the concept of Torrent-Guasp’s myocardial band theory. As the hydrodynamic or hemodynamic examination exhibited the remarkable increase of cardiac systolic work by the assistance of the artificial myocardial contraction in the originally designed mock circulatory system as well as in the acute animal experiments, the chronic animal test has been started in a goat. Total weight of the device including the actuator was around 150g, and the electric power was supplied percutaneously. The device could be successfully installed into thoracic cavity, which was able to be girdling the left ventricle. In the chronic animal trial, the complication in respect to the diastolic dysfunction by the artificial myocardial compression was not observed.

  • Hemodynamic response with an artificial myocardial assistance in chronic animal examination
    IFMBE Proceedings, 2009
    Co-Authors: Yasuyuki Shiraishi, Tomoyuki Yambe, Yoshifumi Saijo, Satoshi Konno, Akira Tanaka, A. Baba, Muneichi Shibata, Telma Keiko Sugai, Tetsuo Fujimoto
    Abstract:

    Thromboembolic and haemorrhagic complications are the primary causes of mortality and morbidity in patients with artificial hearts, which are known to be induced by the interactions between blood flow and artificial material surfaces. The authors have been developing a new mechanical artificial myocardial assist device by using a sophisticated shape memory Alloy Fibre in order to achieve the mechanical cardiac support from outside of the heart without a direct blood contacting surface. The original material employed as the actuator of artificial myocardial assist devices was 100um Fibred-shaped, which was composed of covalent and metallic bonding structure and designed to generate 4-7 % by Joule heating induced by the electric current input. Prior to the experiment, the myocardial streamlines were investigated by using a MDCT, and the design of artificial myocardial assist devices were refined based on the concept of Torrent-Guasp’s myocardial band theory. As the hydrodynamic or hemodynamic examination exhibited the remarkable increase of cardiac systolic work by the assistance of the artificial myocardial contraction in the originally designed mock circulatory system as well as in the acute animal experiments, the chronic animal test has been started in a goat. Total weight of the device including the actuator was around 150g, and the electric power was supplied percutaneously. The device could be successfully installed into thoracic cavity, which was able to be girdling the left ventricle. In the chronic animal trial, the complication in respect to the diastolic dysfunction by the artificial myocardial compression was not observed. Systolic pressure and aortic flow waveforms were elevated by the assistance using the device contraction synchronously by around 5%. And blood pressure response against the increase of aortic pressure was investigated under the myocardial assisted condition in order to examine the vascular tone which was controlled by vagal nervous activity.

  • Assessment of synchronization measures for effective ventricular support by using the shape memory Alloy Fibred artificial myocardium in goats
    2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009
    Co-Authors: Y. Shiraishi, Akira Tanaka, F. Sato, T. K. Sugai, Y. Sato, T. Yambe, Y. Saijo, M. Yoshizawa, Y. Kaneko, M. Uematsu
    Abstract:

    Thromboembolic and haemorrhagic complications are the primary causes of mortality and morbidity in patients with artificial hearts, which are known to be induced by the interactions between blood flow and artificial material surfaces. The authors have been developing a new mechanical artificial myocardial assist device by using a sophisticated shape memory Alloy Fibre in order to achieve the mechanical cardiac support from outside of the heart without a direct blood contacting surface. The original material employed as the actuator of artificial myocardial assist devices was 100 um Fibred-shaped, which was composed of covalent and metallic bonding structure and designed to generate 4-7 % shortening by Joule heating induced by the electric current input. In this study, we focused on the synchronization of the actuator with native cardiac function, and the phase delay parameter was examined in animal experiments using Saanen goats. Total weight of the device including the actuator was around 150 g, and the electric power was supplied transcutaneously. The device could be successfully installed into thoracic cavity, which was able to be girdling the left ventricle. The contraction of the device could be controlled by the originally designed microcomputer. The mechanical contraction signal input had been transmitted with the phase delay of 50-200 msec after the R-wave of ECG, and hemodynamic changes were investigated. Cardiac output and systolic left ventricular pressure were elevated with 20% delay of cardiac cycle by 27% and 7%, respectively, although there was smaller difference under the condition of the delay of over 30%. Therefore, it was suggested that the synchronization measures should be examined in order to achieve sophisticated ventricular passive/active support on physiological demand.