WorldWideScience

Sample records for biomimetic underwater adhesives

  1. Biomimetic Adhesive Materials Containing Cyanoacryl Group for Medical Application

    Directory of Open Access Journals (Sweden)

    Sueng Hwan Jo

    2014-10-01

    Full Text Available For underwater adhesives with biocompatible and more flexible bonds using biomimetic adhesive groups, DOPA-like adhesive molecules were modified with cyanoacrylates to obtain different repeating units and chain length copolymers. The goal of this work is to copy the mechanisms of underwater bonding to create synthetic water-borne underwater medical adhesives through blending of the modified DOPA and a triblock copolymer (PEO-PPO-PEO for practical application to repair wet living tissues and bones, and in turn, to use the synthetic adhesives to test mechanistic hypotheses about the natural adhesive. The highest values in stress and modulus of the biomimetic adhesives prepared in wet state were 165 kPa and 33 MPa, respectively.

  2. Research on biomimetic underwater vehicles for underwater ISR

    Science.gov (United States)

    Szymak, Piotr; Praczyk, Tomasz; Naus, Krzysztof; Szturomski, Bogdan; Malec, Marcin; Morawski, Marcin

    2016-05-01

    Autonomous Biomimetic Underwater Vehicles BUVs driven by an undulating propulsion are a new branch in an area of an underwater robotics. They imitate both the construction and kinematics of a motion of underwater living organisms, e.g. fishes. Such vehicles have several features crucial from the point of view of military applications, e.g. larger secrecy and potential range of operation. The paper presents results of the research on BUVs carried out within two (Polish and EDA) projects both led by Polish Naval Academy. At the beginning, the initial efforts in building Polish BUV called CyberFish are included. Then, selected results of the tests of subsystems, e.g. navigational and 3D model of BUV built within national project are described. Next, the initial research achieved in the international project are showed. At the end, the schedule of the research planned to carry out within both projects is inserted. The paper is mainly focused on the hardware development of the BUVs.

  3. Software architecture of biomimetic underwater vehicle

    Science.gov (United States)

    Praczyk, Tomasz; Szymak, Piotr

    2016-05-01

    Autonomous underwater vehicles are vehicles that are entirely or partly independent of human decisions. In order to obtain operational independence, the vehicles have to be equipped with a specialized software. The main task of the software is to move the vehicle along a trajectory with collision avoidance. Moreover, the software has also to manage different devices installed on the vehicle board, e.g. to start and stop cameras, sonars etc. In addition to the software embedded on the vehicle board, the software responsible for managing the vehicle by the operator is also necessary. Its task is to define mission of the vehicle, to start, to stop the mission, to send emergency commands, to monitor vehicle parameters, and to control the vehicle in remotely operated mode. An important objective of the software is also to support development and tests of other software components. To this end, a simulation environment is necessary, i.e. simulation model of the vehicle and all its key devices, the model of the sea environment, and the software to visualize behavior of the vehicle. The paper presents architecture of the software designed for biomimetic autonomous underwater vehicle (BAUV) that is being constructed within the framework of the scientific project financed by Polish National Center of Research and Development.

  4. Direct observation of microcavitation in underwater adhesion of mushroom-shaped adhesive microstructure

    Directory of Open Access Journals (Sweden)

    Lars Heepe

    2014-06-01

    Full Text Available In this work we report on experiments aimed at testing the cavitation hypothesis [Varenberg, M.; Gorb, S. J. R. Soc., Interface 2008, 5, 383–385] proposed to explain the strong underwater adhesion of mushroom-shaped adhesive microstructures (MSAMSs. For this purpose, we measured the pull-off forces of individual MSAMSs by detaching them from a glass substrate under different wetting conditions and simultaneously video recording the detachment behavior at very high temporal resolution (54,000–100,000 fps. Although microcavitation was observed during the detachment of individual MSAMSs, which was a consequence of water inclusions present at the glass–MSAMS contact interface subjected to negative pressure (tension, the pull-off forces were consistently lower, around 50%, of those measured under ambient conditions. This result supports the assumption that the recently observed strong underwater adhesion of MSAMS is due to an air layer between individual MSAMSs [Kizilkan, E.; Heepe, L.; Gorb, S. N. Underwater adhesion of mushroom-shaped adhesive microstructure: An air-entrapment effect. In Biological and biomimetic adhesives: Challenges and opportunities; Santos, R.; Aldred, N.; Gorb, S. N.; Flammang, P., Eds.; The Royal Society of Chemistry: Cambridge, U.K., 2013; pp 65–71] rather than by cavitation. These results obtained due to the high-speed visualisation of the contact behavior at nanoscale-confined interfaces allow for a microscopic understanding of the underwater adhesion of MSAMSs and may aid in further development of artificial adhesive microstructures for applications in predominantly liquid environments.

  5. Underwater Adhesives Retrofit Pipelines with Advanced Sensors

    Science.gov (United States)

    2015-01-01

    Houston-based Astro Technology Inc. used a partnership with Johnson Space Center to pioneer an advanced fiber-optic monitoring system for offshore oil pipelines. The company's underwater adhesives allow it to retrofit older deepwater systems in order to measure pressure, temperature, strain, and flow properties, giving energy companies crucial data in real time and significantly decreasing the risk of a catastrophe.

  6. Development of Underwater Microrobot with Biomimetic Locomotion

    Directory of Open Access Journals (Sweden)

    W. Zhang

    2006-01-01

    Full Text Available Microrobots have powerful applications in biomedical and naval fields. They should have a compact structure, be easy to manufacture, have efficient locomotion, be driven by low voltage and have a simple control system. To meet these purposes, inspired by the leg of stick insects, we designed a novel type of microrobot with biomimetic locomotion with 1-DOF (degree of freedom legs. The locomotion includes two ionic conducting polymer film (ICPF actuators to realize the 2-DOF motion. We developed several microrobots with this locomotion. Firstly, we review a microrobot, named Walker-1, with 1-DOF motion. And then a new microrobot, named Walker-2, utilizing six ICPF actuators, with 3-DOF motion is introduced. It is 47 mm in diameter and 8 mm in height (in static state. It has 0.61 g of dried weight. We compared the two microrobot prototypes, and the result shows that Walker-2 has some advantages, such as more flexible moving motion, good balance, less water resistance, more load-carrying ability and so on. We also compared it with some insect-inspired microrobots and some microrobots with 1-DOF legs, and the result shows that a microrobot with this novel type of locomotion has some advantages. Its structure has fewer actuators and joints, a simpler control system and is compact. The ICPF actuator decides that it can be driven by low voltage (less than 5 V and move in water. A microrobot with this locomotion has powerful applications in biomedical and naval fields.

  7. Underwater adhesion: The barnacle way

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.

    rosa and demonstrated the stimulatory effect of dopamine and noradrenaline on such secretion. Their study indicated exocytosis to be the major mode of cement secretion and suggest that gradual, localized exocytotic secretion of cement triggered... by catecholaminergic neurons to be the key mechanism during permanent attachment by barnacle cyprids [51]. Properties of barnacle adhesive The resistance to chemical breakdown by barnacle adhesive caused a major problem in its characterization. However...

  8. Braking Performance of a Biomimetic Squid-Like Underwater Robot

    Institute of Scientific and Technical Information of China (English)

    Md.Mahbubar Rahman; Sinpei Sugimori; Hiroshi Miki; Risa Yamamoto; Yugo Sanada; Yasuyuki Toda

    2013-01-01

    In this study,the braking performance of the undulating fin propulsion system ofa biomimetic squid-like underwater robot was investigated through free run experiment and simulation of the quasi-steady mathematical model.The quasi-steady equations of motion were solved using the measured and calculated hydrodynamic forces and compared with free-run test results.Various braking strategies were tested and discussed in terms of stopping ability and the forces acting on the stopping stage.The stopping performance of the undulating fin propulsion system tured out to be excellent considering the short stopping time and short stopping distance.This is because of the large negative thrust produced by progressive wave in opposite direction.It was confirmed that the undulating fin propulsion system can effectively perform braking even in complex underwater explorations.

  9. Embedded SMA wire actuated biomimetic fin: a module for biomimetic underwater propulsion

    Science.gov (United States)

    Wang, Zhenlong; Hang, Guanrong; Wang, Yangwei; Li, Jian; Du, Wei

    2008-04-01

    An embedded shape memory alloy (SMA) wire actuated biomimetic fin is presented, and based on this module for biomimetic underwater propulsion, a micro robot fish (146 mm in length, 30 g in weight) and a robot squid (242 mm in length, 360 g in weight) were developed. Fish swim by undulating their body and/or fins. Squid and cuttlefish can also swim by undulating their fins. To simplify engineering modeling, the undulating swimming movement is assumed to be the integration of the movements of many flexible bending segments connected in parallel or in series. According to this idea, a biomimetic fin which can bend flexibly was developed. The musculature of a cuttlefish fin was investigated to aid the design of the biomimetic fin. SMA wires act as 'muscle fibers' to drive the biomimetic fin just like the transverse muscles of the cuttlefish fin. During the bending phase, elastic energy is stored in the elastic substrate and skin, and during the return phase, elastic energy is released to power the return movement. Theorem analysis of the bending angle was performed to estimate the bending performance of the biomimetic fin. Experiments were carried out on single-face fins with latex rubber skin and silicone skin (SF-L and SF-S) to compare the bending angle, return time, elastic energy storage and reliability. Silicone was found to be the better skin. A dual-face fin with silicone skin (DF-S) was tested in water to evaluate the actuating performance and to validate the reliability. Thermal analysis of the SMA temperature was performed to aid the control strategy. The micro robot fish and robot squid employ one and ten DF-S, respectively. Swimming experiments with different actuation frequencies were carried out. The speed and steering radius of the micro robot fish reached 112 mm s-1 and 136 mm, respectively, and the speed and rotary speed of the robot squid reached 40 mm s-1 and 22° s-1, respectively.

  10. Embedded SMA wire actuated biomimetic fin: a module for biomimetic underwater propulsion

    International Nuclear Information System (INIS)

    An embedded shape memory alloy (SMA) wire actuated biomimetic fin is presented, and based on this module for biomimetic underwater propulsion, a micro robot fish (146 mm in length, 30 g in weight) and a robot squid (242 mm in length, 360 g in weight) were developed. Fish swim by undulating their body and/or fins. Squid and cuttlefish can also swim by undulating their fins. To simplify engineering modeling, the undulating swimming movement is assumed to be the integration of the movements of many flexible bending segments connected in parallel or in series. According to this idea, a biomimetic fin which can bend flexibly was developed. The musculature of a cuttlefish fin was investigated to aid the design of the biomimetic fin. SMA wires act as 'muscle fibers' to drive the biomimetic fin just like the transverse muscles of the cuttlefish fin. During the bending phase, elastic energy is stored in the elastic substrate and skin, and during the return phase, elastic energy is released to power the return movement. Theorem analysis of the bending angle was performed to estimate the bending performance of the biomimetic fin. Experiments were carried out on single-face fins with latex rubber skin and silicone skin (SF-L and SF-S) to compare the bending angle, return time, elastic energy storage and reliability. Silicone was found to be the better skin. A dual-face fin with silicone skin (DF-S) was tested in water to evaluate the actuating performance and to validate the reliability. Thermal analysis of the SMA temperature was performed to aid the control strategy. The micro robot fish and robot squid employ one and ten DF-S, respectively. Swimming experiments with different actuation frequencies were carried out. The speed and steering radius of the micro robot fish reached 112 mm s−1 and 136 mm, respectively, and the speed and rotary speed of the robot squid reached 40 mm s−1 and 22° s−1, respectively

  11. Strong, reversible underwater adhesion via gecko-inspired hydrophobic fibers.

    Science.gov (United States)

    Soltannia, Babak; Sameoto, Dan

    2014-12-24

    Strong, reversible underwater adhesion using gecko-inspired surfaces is achievable through the use of a hydrophobic structural material and does not require surface modification or suction cup effects for this adhesion to be effective. Increased surface energy can aid in dry adhesion in an air environment but strongly degrades wet adhesion via reduction of interfacial energy underwater. A direct comparison of structurally identical but chemically different mushroom shaped fibers shows that strong, reversible adhesion, even in a fully wetted, stable state, is feasible underwater if the structural material of the fibers is hydrophobic and the mating surface is not strongly hydrophilic. The exact adhesion strength will be a function of the underwater interfacial energy between surfaces and the specific failure modes of individual fibers. This underwater adhesion has been calculated to be potentially greater than the dry adhesion for specific combinations of hydrophobic surfaces.

  12. Strong underwater adhesives made by self-assembling multi-protein nanofibres.

    Science.gov (United States)

    Zhong, Chao; Gurry, Thomas; Cheng, Allen A; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M; Lu, Timothy K

    2014-10-01

    Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly and structure-function relationships of these natural amyloid fibres remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibres. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibres have an underwater adhesion energy approaching 20.9 mJ m(-2), which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibres taken on their own and exhibit better tolerance to auto-oxidation than Mfps at pH ≥ 7.0.

  13. Strong underwater adhesives made by self-assembling multi-protein nanofibres

    Science.gov (United States)

    Zhong, Chao; Gurry, Thomas; Cheng, Allen A.; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M.; Lu, Timothy K.

    2014-10-01

    Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly and structure-function relationships of these natural amyloid fibres remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibres. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibres have an underwater adhesion energy approaching 20.9 mJ m-2, which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibres taken on their own and exhibit better tolerance to auto-oxidation than Mfps at pH ≥ 7.0.

  14. A batch fabricated biomimetic dry adhesive

    Science.gov (United States)

    Northen, Michael T.; Turner, Kimberly L.

    2005-08-01

    The fine hair adhesive system found in nature is capable of reversibly adhering to just about any surface. This dry adhesive, best demonstrated in the pad of the gecko, makes use of a multilevel conformal structure to greatly increase inelastic surface contact, enhancing short range interactions and producing significant amounts of attractive forces. Recent work has attempted to reproduce and test the terminal submicrometre 'hairs' of the system. Here we report the first batch fabricated multi-scale conformal system to mimic nature's dry adhesive. The approach makes use of massively parallel MEMS processing technology to produce 20-150 µm platforms, supported by single slender pillars, and coated with ~2 µm long, ~200 nm diameter, organic looking polymer nanorods, or 'organorods'. To characterize the structures a new mesoscale nanoindenter adhesion test technique has been developed. Experiments indicate significantly improved adhesion with the multiscale system. Additional processing caused a hydrophilic to hydrophobic transformation of the surface and testing indicated further improvement in adhesion.

  15. Isolation and biochemical characterization of underwater adhesives from diatoms.

    Science.gov (United States)

    Poulsen, Nicole; Kröger, Nils; Harrington, Matthew J; Brunner, Eike; Paasch, Silvia; Buhmann, Matthias T

    2014-01-01

    Many aquatic organisms are able to colonize surfaces through the secretion of underwater adhesives. Diatoms are unicellular algae that have the capability to colonize any natural and man-made submerged surfaces. There is great technological interest in both mimicking and preventing diatom adhesion, yet the biomolecules responsible have so far remained unidentified. A new method for the isolation of diatom adhesive material is described and its amino acid and carbohydrate composition determined. The adhesive materials from two model diatoms show differences in their amino acid and carbohydrate compositions, but also share characteristic features including a high content of uronic acids, the predominance of hydrophilic amino acid residues, and the presence of 3,4-dihydroxyproline, an extremely rare amino acid. Proteins containing dihydroxyphenylalanine, which mediate underwater adhesion of mussels, are absent. The data on the composition of diatom adhesives are consistent with an adhesion mechanism based on complex coacervation of polyelectrolyte-like biomolecules.

  16. A biomimetic underwater vehicle actuated by waves with ionic polymer-metal composite soft sensors.

    Science.gov (United States)

    Shen, Qi; Wang, Tianmiao; Kim, Kwang J

    2015-10-01

    The ionic polymer-metal composite (IPMC) is a soft material based actuator and sensor and has a promising potential in underwater application. This paper describes a hybrid biomimetic underwater vehicle that uses IPMCs as sensors. Propelled by the energy of waves, this underwater vehicle does not need an additional energy source. A physical model based on the hydrodynamics of the vehicle was developed, and simulations were conducted. Using the Poisson-Nernst-Planck system of equations, a physics model for the IPMC sensor was proposed. For this study, experimental apparatus was developed to conduct hydrodynamic experiments for both the underwater vehicle and the IPMC sensors. By comparing the experimental and theoretical results, the speed of the underwater vehicle and the output of the IPMC sensors were well predicted by the theoretical models. A maximum speed of 1.08 × 10(-1) m s(-1) was recorded experimentally at a wave frequency of 1.6 Hz. The peak output voltage of the IPMC sensor was 2.27 × 10(-4) V, recorded at 0.8 Hz. It was found that the speed of the underwater vehicle increased as the wave frequency increased and the IPMC output decreased as the wave frequency increased. Further, the energy harvesting capabilities of the underwater vehicle hosting the IPMCs were tested. A maximum power of 9.50 × 10(-10) W was recorded at 1.6 Hz. PMID:26414228

  17. TOPICAL REVIEW: Recent advances in the fabrication and adhesion testing of biomimetic dry adhesives

    Science.gov (United States)

    Sameoto, D.; Menon, C.

    2010-10-01

    In the past two years, there have been a large number of publications on the topic of biomimetic dry adhesives from modeling, fabrication and testing perspectives. We review and compare the most recent advances in fabrication and testing of these materials. While there is increased convergence and consensus as to what makes a good dry adhesive, the fabrication of these materials is still challenging, particularly for anisotropic or hierarchal designs. Although qualitative comparisons between different adhesive designs can be made, quantifying the exact performance and rating each design is significantly hampered by the lack of standardized testing methods. Manufacturing dry adhesives, which can reliably adhere to rough surfaces, show directional and self-cleaning behavior and are relatively simple to manufacture, is still very challenging—great strides by multiple research groups have however made these goals appear achievable within the next few years.

  18. Coordination of Multiple Biomimetic Autonomous Underwater Vehicles Using Strategies Based on the Schooling Behaviour of Fish

    Directory of Open Access Journals (Sweden)

    Jonathan McColgan

    2016-01-01

    Full Text Available Biomimetic Autonomous Underwater Vehicles (BAUVs are Autonomous Underwater Vehicles (AUVs that employ similar propulsion and steering principles as real fish. While the real life applicability of these vehicles has yet to be fully investigated, laboratory investigations have demonstrated that at low speeds, the propulsive mechanism of these vehicles is more efficient when compared with propeller based AUVs. Furthermore, these vehicles have also demonstrated superior manoeuvrability characteristics when compared with conventional AUVs and Underwater Glider Systems (UGSs. Further performance benefits can be achieved through coordination of multiple BAUVs swimming in formation. In this study, the coordination strategy is based on the schooling behaviour of fish, which is a decentralized approach that allows multiple AUVs to be self-organizing. Such a strategy can be effectively utilized for large spatiotemporal data collection for oceanic monitoring and surveillance purposes. A validated mathematical model of the BAUV developed at the University of Glasgow, RoboSalmon, is used to represent the agents within a school formation. The performance of the coordination algorithm is assessed through simulation where system identification techniques are employed to improve simulation run time while ensuring accuracy is maintained. The simulation results demonstrate the effectiveness of implementing coordination algorithms based on the behavioural mechanisms of fish to allow a group of BAUVs to be considered self-organizing.

  19. The design of underwater superoleophobic Ni/NiO microstructures with tunable oil adhesion

    Science.gov (United States)

    Zhang, Enshuang; Cheng, Zhongjun; Lv, Tong; Li, Li; Liu, Yuyan

    2015-11-01

    Controlling oil adhesion in water is a fundamental issue in many practical applications for surfaces. Currently, almost all studies on underwater oil adhesion control are concentrated on regulating surface chemistry on polymer surfaces, and structure-dependent underwater oil adhesion is still rare, especially on inorganic materials. Herein, we report a series of underwater superoleophobic Ni/NiO surfaces with controlled oil adhesions by combining electro-deposition and heating techniques. The adhesive forces between an oil droplet and the surfaces can be adjusted from an extremely low (less than 1 μN) to a very high value (about 60 μN), and the tunable effect can be attributed to different wetting states that result from different microstructures on the surfaces. Moreover, the oil-adhesion controllability for different types of oils was also analyzed and the applications of the surface including oil droplet transportation and self-cleaning were discussed. The results reported herein provide a new feasible method for fabrication of underwater superoleophobic surfaces with controlled adhesion, and improve the understanding of the relationship between surface microstructures, adhesion, and the fabrication principle of tunable oil adhesive surfaces.Controlling oil adhesion in water is a fundamental issue in many practical applications for surfaces. Currently, almost all studies on underwater oil adhesion control are concentrated on regulating surface chemistry on polymer surfaces, and structure-dependent underwater oil adhesion is still rare, especially on inorganic materials. Herein, we report a series of underwater superoleophobic Ni/NiO surfaces with controlled oil adhesions by combining electro-deposition and heating techniques. The adhesive forces between an oil droplet and the surfaces can be adjusted from an extremely low (less than 1 μN) to a very high value (about 60 μN), and the tunable effect can be attributed to different wetting states that result from

  20. A low-cost, high-yield fabrication method for producing optimized biomimetic dry adhesives

    Science.gov (United States)

    Sameoto, D.; Menon, C.

    2009-11-01

    We present a low-cost, large-scale method of fabricating biomimetic dry adhesives. This process is useful because it uses all photosensitive polymers with minimum fabrication costs or complexity to produce molds for silicone-based dry adhesives. A thick-film lift-off process is used to define molds using AZ 9260 photoresist, with a slow acting, deep UV sensitive material, PMGI, used as both an adhesion promoter for the AZ 9260 photoresist and as an undercutting material to produce mushroom-shaped fibers. The benefits to this process are ease of fabrication, wide range of potential layer thicknesses, no special surface treatment requirements to demold silicone adhesives and easy stripping of the full mold if process failure does occur. Sylgard® 184 silicone is used to cast full sheets of biomimetic dry adhesives off 4" diameter wafers, and different fiber geometries are tested for normal adhesion properties. Additionally, failure modes of the adhesive during fabrication are noted and strategies for avoiding these failures are discussed. We use this fabrication method to produce different fiber geometries with varying cap diameters and test them for normal adhesion strengths. The results indicate that the cap diameters relative to post diameters for mushroom-shaped fibers dominate the adhesion properties.

  1. Design and Implementation of a Biomimetic Turtle Hydrofoil for an Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Jordi Palacin

    2011-11-01

    Full Text Available This paper presents the design and implementation of a turtle hydrofoil for an Autonomous Underwater Vehicle (AUV. The final design of the AUV must have navigation performance like a turtle, which has also been the biomimetic inspiration for the design of the hydrofoil and propulsion system. The hydrofoil design is based on a National Advisory Committee for Aeronautics (NACA 0014 hydrodynamic profile. During the design stage, four different propulsion systems were compared in terms of propulsion path, compactness, sealing and required power. The final implementation is based on a ball-and-socket mechanism because it is very compact and provides three degrees of freedom (DoF to the hydrofoil with very few restrictions on the propulsion path. The propulsion obtained with the final implementation of the hydrofoil has been empirically evaluated in a water channel comparing different motion strategies. The results obtained have confirmed that the proposed turtle hydrofoil controlled with a mechanism with three DoF generates can be used in the future implementation of the planned AUV.

  2. Design and implementation of a biomimetic turtle hydrofoil for an autonomous underwater vehicle.

    Science.gov (United States)

    Font, Davinia; Tresanchez, Marcel; Siegentahler, Cedric; Pallejà, Tomàs; Teixidó, Mercè; Pradalier, Cedric; Palacin, Jordi

    2011-01-01

    This paper presents the design and implementation of a turtle hydrofoil for an Autonomous Underwater Vehicle (AUV). The final design of the AUV must have navigation performance like a turtle, which has also been the biomimetic inspiration for the design of the hydrofoil and propulsion system. The hydrofoil design is based on a National Advisory Committee for Aeronautics (NACA) 0014 hydrodynamic profile. During the design stage, four different propulsion systems were compared in terms of propulsion path, compactness, sealing and required power. The final implementation is based on a ball-and-socket mechanism because it is very compact and provides three degrees of freedom (DoF) to the hydrofoil with very few restrictions on the propulsion path. The propulsion obtained with the final implementation of the hydrofoil has been empirically evaluated in a water channel comparing different motion strategies. The results obtained have confirmed that the proposed turtle hydrofoil controlled with a mechanism with three DoF generates can be used in the future implementation of the planned AUV.

  3. Design and Implementation of a Biomimetic Turtle Hydrofoil for an Autonomous Underwater Vehicle

    Science.gov (United States)

    Font, Davinia; Tresanchez, Marcel; Siegentahler, Cedric; Pallejà, Tomàs; Teixidó, Mercè; Pradalier, Cedric; Palacin, Jordi

    2011-01-01

    This paper presents the design and implementation of a turtle hydrofoil for an Autonomous Underwater Vehicle (AUV). The final design of the AUV must have navigation performance like a turtle, which has also been the biomimetic inspiration for the design of the hydrofoil and propulsion system. The hydrofoil design is based on a National Advisory Committee for Aeronautics (NACA) 0014 hydrodynamic profile. During the design stage, four different propulsion systems were compared in terms of propulsion path, compactness, sealing and required power. The final implementation is based on a ball-and-socket mechanism because it is very compact and provides three degrees of freedom (DoF) to the hydrofoil with very few restrictions on the propulsion path. The propulsion obtained with the final implementation of the hydrofoil has been empirically evaluated in a water channel comparing different motion strategies. The results obtained have confirmed that the proposed turtle hydrofoil controlled with a mechanism with three DoF generates can be used in the future implementation of the planned AUV. PMID:22247660

  4. Design and implementation of a biomimetic turtle hydrofoil for an autonomous underwater vehicle.

    Science.gov (United States)

    Font, Davinia; Tresanchez, Marcel; Siegentahler, Cedric; Pallejà, Tomàs; Teixidó, Mercè; Pradalier, Cedric; Palacin, Jordi

    2011-01-01

    This paper presents the design and implementation of a turtle hydrofoil for an Autonomous Underwater Vehicle (AUV). The final design of the AUV must have navigation performance like a turtle, which has also been the biomimetic inspiration for the design of the hydrofoil and propulsion system. The hydrofoil design is based on a National Advisory Committee for Aeronautics (NACA) 0014 hydrodynamic profile. During the design stage, four different propulsion systems were compared in terms of propulsion path, compactness, sealing and required power. The final implementation is based on a ball-and-socket mechanism because it is very compact and provides three degrees of freedom (DoF) to the hydrofoil with very few restrictions on the propulsion path. The propulsion obtained with the final implementation of the hydrofoil has been empirically evaluated in a water channel comparing different motion strategies. The results obtained have confirmed that the proposed turtle hydrofoil controlled with a mechanism with three DoF generates can be used in the future implementation of the planned AUV. PMID:22247660

  5. Deep UV patterning of acrylic masters for molding biomimetic dry adhesives

    Science.gov (United States)

    Sameoto, D.; Menon, C.

    2010-11-01

    We present a novel fabrication method for the production of biomimetic dry adhesives that allows enormous variation in fiber shapes and sizes. The technology is based on deep-UV patterning of commercial acrylic with semi-collimated light available from germicidal lamps, and combined careful processing conditions, material selection and novel developer choices to produce relatively high-aspect-ratio fibers with overhanging caps on large areas. These acrylic fibers are used as a master mold for subsequent silicone rubber negative mold casting. Because the bulk acrylic demonstrates little inherent adhesion to silicone rubbers, the master molds created in this process do not require any surface treatments to achieve high-yield demolding of interlocked structures. Multiple polymers can be cast from silicone rubber negative molds and this process could be used to structure smart materials on areas over multiple square feet. Using direct photopatterning of acrylic allows many of the desired structures for biomimetic dry adhesives to be produced with relative ease compared to silicon-based molding processes, including angled fibers and hierarchical structures. Optimized fiber shapes for a variety of polymers can be produced using this process, and adhesion measurements on a well-characterized polyurethane, ST-1060, are used to determine the effect of fiber geometry on adhesion performance.

  6. Biomimetic jellyfish-inspired underwater vehicle actuated by ionic polymer metal composite actuators

    International Nuclear Information System (INIS)

    This paper presents the design, fabrication, and characterization of a biomimetic jellyfish robot that uses ionic polymer metal composites (IPMCs) as flexible actuators for propulsion. The shape and swimming style of this underwater vehicle are based on the Aequorea victoria jellyfish, which has an average swimming speed of 20 mm s−1 and which is known for its high swimming efficiency. The Aequorea victoria is chosen as a model system because both its bell morphology and kinematic properties match the mechanical properties of IPMC actuators. This medusa is characterized by its low swimming frequency, small bell deformation during the contraction phase, and high Froude efficiency. The critical components of the robot include the flexible bell that provides the overall shape and dimensions of the jellyfish, a central hub and a stage used to provide electrical connections and mechanical support to the actuators, eight distinct spars meant to keep the upper part of the bell stationary, and flexible IPMC actuators that extend radially from the central stage. The bell is fabricated from a commercially available heat-shrinkable polymer film to provide increased shape-holding ability and reduced weight. The IPMC actuators constructed for this study demonstrated peak-to-peak strains of ∼0.7% in water across a frequency range of 0.1–1.0 Hz. By tailoring the applied voltage waveform and the flexibility of the bell, the completed robotic jellyfish with four actuators swam at an average speed 0.77 mm s−1 and consumed 0.7 W. When eight actuators were used the average speed increased to 1.5 mm s−1 with a power consumption of 1.14 W. (paper)

  7. Release of celecoxib from a bi-layer biomimetic tendon sheath to prevent tissue adhesion.

    Science.gov (United States)

    Li, Laifeng; Zheng, Xianyou; Fan, Dapeng; Yu, Shiyang; Wu, Di; Fan, Cunyi; Cui, Wenguo; Ruan, Hongjiang

    2016-04-01

    Posttraumatic tendon adhesion limits the motion of the limbs greatly. Biomimetic tendon sheaths have been developed to promote tendon healing and gliding. However, after introduction of these biomaterials, the associated inflammatory responses can decrease the anti-adhesion effect. Celecoxib is a non-steroidal anti-inflammatory drug (NSAID) that can decrease inflammation responses. We blended hyaluronic acid and poly(l-lactic acid)-polyethylene glycol (PELA) with microgel electrospinning technology to form an inner layer of a bi-layer biomimetic sheath using sequential electrospinning of an outer celecoxib-PELA layer. Electrospun bi-layer fibrous membranes were mechanically tested and characterized by morphology, surface wettability, and drug release. The tensile strength showed a decreased trend and water contact angles were 114.7 ± 3.9°, 103.6 ± 4.4°, 116.3 ± 5.1°, 122.8 ± 4.7°, and 126.5 ± 4.2° for the surface of PELA, hyaluronic acid-PELA, 2, 6, and 10% celecoxib-PELA electrospun fibrous membranes, respectively. In vitro drug release studies confirmed burst release and then sustained release from the fibrous membranes containing celecoxib for 20 days. In a chicken model of flexor digitorum profundus tendon surgery, the outer celecoxib/PELA layer offered advanced anti-adhesion roles compared to the outer PELA layer and the inner hyaluronic acid-loaded PELA layer still offered tendon healing and gliding. Thus, celecoxib-loaded anti-adhesive tendon sheaths can continuously offer bi-layer biomimetic tendon sheath effects with celecoxib release from the outer layer to prevent tendon adhesion. PMID:26838844

  8. Adhesion enhancement of biomimetic dry adhesives by nanoparticle in situ synthesis

    Science.gov (United States)

    Díaz Téllez, J. P.; Harirchian-Saei, S.; Li, Y.; Menon, C.

    2013-10-01

    A novel method to increase the adhesion strength of a gecko-inspired dry adhesive is presented. Gold nanoparticles are synthesized on the tips of the microfibrils of a polymeric dry adhesive to increase its Hamaker constant. Formation of the gold nanoparticles is qualitatively studied through a colour change in the originally transparent substance and quantitatively analysed using ultraviolet-visible spectrophotometry. A pull-off force test is employed to quantify the adhesion enhancement. Specifically, adhesion forces of samples with and without embedded gold nanoparticles are measured and compared. The experimental results indicate that an adhesion improvement of 135% can be achieved.

  9. Biomimetics

    Indian Academy of Sciences (India)

    P Ramachandra Rao

    2003-06-01

    The well-organised multifunctional structures, systems and biogenic materials found in nature have attracted the interest of scientists working in many disciplines. The efforts have resulted in the development of a new and rapidly growing field of scientific effort called biomimetics. In this article we present a few natural materials and systems and explore how ideas from nature are being interpreted and modified to suit efforts aimed at designing better machines and synthesising newer materials.

  10. Underwater Reversible Adhesion Between Oppositely Charged Weak Polyelectrolytes

    Science.gov (United States)

    Alfhaid, Latifah; Geoghegan, Mark; Williams, Nicholas; Seddon, William

    2015-03-01

    Force-distance data has shown that the adhesion between two oppositely charged polyelectrolytes: poly(methacrylic acid) (PMAA, a polyacid) and poly[2-(diethylamino)ethyl methacrylate] (PDEAEMA, a polybase), was controllable by varying the pH level of their surrounding. Accordingly, adhesive force at the interface between these two polymers was higher inside basic surroundings at pH 6 and 7, and then it started to decrease at pH level below 3 and above 8. Stimulating adhesion between PMAA gel and PDEAEMA brushes by adding salt to their surrounded water has only a limited effect on the adhesive force between them, contradicting previous results. Increasing the molar concentration of sodium chloride (NaCl) in the surrounded water of these two polymers from 0.1 to 1M did not decrease the adhesion forces between a PMAA gel and a grafted PDEAEMA layer (brush). The JKR equation was used to evaluate the adhesion forces between the polymer gel and the brushes and it was observed that the adhesion increased with the elastic modulus of the gel decreased.

  11. Friction and adhesion of hierarchical carbon nanotube structures for biomimetic dry adhesives: multiscale modeling.

    Science.gov (United States)

    Hu, Shihao; Jiang, Haodan; Xia, Zhenhai; Gao, Xiaosheng

    2010-09-01

    With unique hierarchical fibrillar structures on their feet, gecko lizards can walk on vertical walls or even ceilings. Recent experiments have shown that strong binding along the shear direction and easy lifting in the normal direction can be achieved by forming unidirectional carbon nanotube array with laterally distributed tips similar to gecko's feet. In this study, a multiscale modeling approach was developed to analyze friction and adhesion behaviors of this hierarchical fibrillar system. Vertically aligned carbon nanotube array with laterally distributed segments at the end was simulated by coarse grained molecular dynamics. The effects of the laterally distributed segments on friction and adhesion strengths were analyzed, and further adopted as cohesive laws used in finite element analysis at device scale. The results show that the laterally distributed segments play an essential role in achieving high force anisotropy between normal and shear directions in the adhesives. Finite element analysis reveals a new friction-enhanced adhesion mechanism of the carbon nanotube array, which also exists in gecko adhesive system. The multiscale modeling provides an approach to bridge the microlevel structures of the carbon nanotube array with its macrolevel adhesive behaviors, and the predictions from this modeling give an insight into the mechanisms of gecko-mimicking dry adhesives.

  12. Underwater contact adhesion and microarchitecture in polyelectrolyte complexes actuated by solvent exchange

    Science.gov (United States)

    Zhao, Qiang; Lee, Dong Woog; Ahn, B. Kollbe; Seo, Sungbaek; Kaufman, Yair; Israelachvili, Jacob N.; Waite, J. Herbert

    2016-04-01

    Polyelectrolyte complexation is critical to the formation and properties of many biological and polymeric materials, and is typically initiated by aqueous mixing followed by fluid-fluid phase separation, such as coacervation. Yet little to nothing is known about how coacervates evolve into intricate solid microarchitectures. Inspired by the chemical features of the cement proteins of the sandcastle worm, here we report a versatile and strong wet-contact microporous adhesive resulting from polyelectrolyte complexation triggered by solvent exchange. After premixing a catechol-functionalized weak polyanion with a polycation in dimethyl sulphoxide (DMSO), the solution was applied underwater to various substrates whereupon electrostatic complexation, phase inversion, and rapid setting were simultaneously actuated by water-DMSO solvent exchange. Spatial and temporal coordination of complexation, inversion and setting fostered rapid (~25 s) and robust underwater contact adhesion (Wad >= 2 J m-2) of complexed catecholic polyelectrolytes to all tested surfaces including plastics, glasses, metals and biological materials.

  13. Under-water adhesion of rigid spheres on soft, charged surfaces

    Science.gov (United States)

    Sinha, Shayandev; Das, Siddhartha

    2015-11-01

    Adhesion in a liquid medium is fundamentally important for understanding a myriad of physiological and technological issues such as nanoparticle or bacteria uptake by cells, attachment of viruses on bacterial surfaces, adhesion of a bacteria on a preformed biofilm, biofouling of ships and marine vehicles, and many more. In this paper, we provide a theory to analyze the under-water adhesion of a rigid spherical particle on a soft, charged surface, which is represented as a layer of grafted polyelectrolyte layer (PEL). Our model is based on calculating and minimizing the free energy, appropriately modified to account for the PEL electric double layer (EDL) induced electrostatic energies. The central result of our paper is that the presence of surface charge typically enhances the adhesion, indicated by a larger negative value of the equilibrium free energy and larger value of the equilibrium depth of indentation. Such a behavior can be explained by noting that the lowering of EDL electrostatic energy due to adhesion better balances the increase in elastic energy caused by the adhesion-induced deformation. We anticipate that our theory will provide the hitherto unknown basis of quantifying the effect of surface charge in under-liquid adhesion, which is central to the vast number of phenomena involving charged bio-systems, like cells, bacteria, and viruses.

  14. Design specifications of the Human Robotic interface for the biomimetic underwater robot "yellow submarine project"

    OpenAIRE

    Bheemaiah, Anil

    2010-01-01

    This paper describes the design of a web based multi agent design for a collision avoidance auto navigation biomimetic submarine for submarine hydroelectricity. The paper describes the nature of the map - topology interface for river bodies and the design of interactive agents for the control of the robotic submarine. The agents are migratory on the web and are designed in XML/html interface with both interactive capabilities and visibility on a map. The paper describes mathematically the use...

  15. Matching Forces Applied in Underwater Hull Cleaning with Adhesion Strength of Marine Organisms

    Directory of Open Access Journals (Sweden)

    Dinis Oliveira

    2016-10-01

    Full Text Available Biofouling is detrimental to the hydrodynamic performance of ships. In spite of advances in hull coating technology, a ship must usually undergo underwater hull cleaning to remove biofouling during her in-service time. However, some cleaning practices may also lead to decreased lifetime of the fouling-control coating. Therefore, cleaning forces should be minimized, according to the adhesion strength of marine organisms present on the hull. In this article, values of adhesion strength found in available literature are discussed in the light of current knowledge on hull cleaning technology. Finally, the following knowledge gaps are identified: (1 data on adhesion strength of naturally-occurring biofouling communities are practically absent; (2 shear forces imparted by current cleaning devices on low-form fouling (microfouling and corresponding effects on hull coatings are largely unknown. This knowledge would be valuable for both developers and users of cleaning technology.

  16. Evaluation of Underwater Adhesives and Friction Coatings for In Situ Attachment of Fiber Optic Sensor System for Subsea Applications

    Science.gov (United States)

    Tang, Henry H.; Le, Suy Q.; Orndoff, Evelyne S.; Smith, Frederick D.; Tapia, Alma S.; Brower, David V.

    2012-01-01

    Integrity and performance monitoring of subsea pipelines and structures provides critical information for managing offshore oil and gas production operation and preventing environmentally damaging and costly catastrophic failure. Currently pipeline monitoring devices require ground assembly and installation prior to the underwater deployment of the pipeline. A monitoring device that could be installed in situ on the operating underwater structures could enhance the productivity and improve the safety of current offshore operation. Through a Space Act Agreement (SAA) between the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) and Astro Technology, Inc. (ATI), JSC provides technical expertise and testing facilities to support the development of fiber optic sensor technologies by ATI. This paper details the first collaboration effort between NASA JSC and ATI in evaluating underwater applicable adhesives and friction coatings for attaching fiber optic sensor system to subsea pipeline. A market survey was conducted to examine different commercial ]off ]the ]shelf (COTS) underwater adhesive systems and to select adhesive candidates for testing and evaluation. Four COTS epoxy based underwater adhesives were selected and evaluated. The adhesives were applied and cured in simulated seawater conditions and then evaluated for application characteristics and adhesive strength. The adhesive that demonstrated the best underwater application characteristics and highest adhesive strength were identified for further evaluation in developing an attachment system that could be deployed in the harsh subsea environment. Various friction coatings were also tested in this study to measure their shear strengths for a mechanical clamping design concept for attaching fiber optic sensor system. A COTS carbide alloy coating was found to increase the shear strength of metal to metal clamping interface by up to 46 percent. This study provides valuable data for

  17. Biomimetic mushroom-shaped microfibers for dry adhesives by electrically induced polymer deformation.

    Science.gov (United States)

    Hu, Hong; Tian, Hongmiao; Li, Xiangming; Shao, Jinyou; Ding, Yucheng; Liu, Hongzhong; An, Ningli

    2014-08-27

    The studies on bioinspired dry adhesion have demonstrated the biomimetic importance of a surface arrayed with mushroom-shaped microfibers among other artificially textured surfaces. The generation of a mushroom-shaped microfiber array with a high aspect ratio and a large tip diameter remains to be investigated. In this paper we report a three-step process for producing mushroom-shaped microfibers with a well-controlled aspect ratio and tip diameter. First, a polymer film coated on an electrically conductive substrate is prestructured into a low-aspect-ratio micropillar array by hot embossing. In the second step, an electrical voltage is applied to an electrode pair composed of the substrate and another conductive planar plate, sandwiching an air clearance. The Maxwell force induced on the air-polymer interface by the electric field electrohydrodynamically pulls the preformed micropillars upward to contact the upper electrode. Finally, the micropillars spread transversely on this electrode due to the electrowetting effect, forming the mushroom tip. In this paper we have demonstrated a polymer surface arrayed with mushroom-shaped microfibers with a large tip diameter (3 times the shaft diameter) and a large aspect ratio (above 10) and provided the testing results for dry adhesion.

  18. Design specifications of the Human Robotic interface for the biomimetic underwater robot "yellow submarine project"

    CERN Document Server

    Bheemaiah, Anil

    2010-01-01

    This paper describes the design of a web based multi agent design for a collision avoidance auto navigation biomimetic submarine for submarine hydroelectricity. The paper describes the nature of the map - topology interface for river bodies and the design of interactive agents for the control of the robotic submarine. The agents are migratory on the web and are designed in XML/html interface with both interactive capabilities and visibility on a map. The paper describes mathematically the user interface and the map definition languages used for the multi agent description

  19. Significance of the conformation of building blocks in curing of barnacle underwater adhesive.

    Science.gov (United States)

    Kamino, Kei; Nakano, Masahiro; Kanai, Satoru

    2012-05-01

    Barnacles are a unique sessile crustacean that attach irreversibly and firmly to foreign underwater surfaces. Its biological underwater adhesive is a peculiar extracellular multi-protein complex. Here we characterize one of the two major proteins, a 52 kDa protein found in the barnacle cement complex. Cloning of the cDNA revealed that the protein has no homolog in the nonredundant database. The primary structure consists of four long sequence repeats. The process of dissolving the protein at the adhesive joint of the animal by various treatments was monitored in order to obtain insight into the molecular mechanism involved in curing of the adhesive bulk. Treatments with protein denaturant, reducing agents and/or chemical-specific proteolysis in combination with 2D diagonal PAGE indicated no involvement of the protein in intermolecular cross-linkage/polymerization, including formation of intermolecular disulfide bonds. As solubilization of the proteins required high concentrations of denaturing agents, it appears that both the conformation of the protein as building blocks and non-covalent molecular interactions between the building blocks, possibly hydrophobic interactions and hydrogen bonds, are crucial for curing of the cement. It was also suggested that the protein contributes to surface coupling by an anchoring effect to micro- to nanoscopic roughness of surfaces.

  20. MEMS sensors for assessing flow-related control of an underwater biomimetic robotic stingray.

    Science.gov (United States)

    Asadnia, Mohsen; Kottapalli, Ajay Giri Prakash; Haghighi, Reza; Cloitre, Audren; Alvarado, Pablo Valdivia Y; Miao, Jianmin; Triantafyllou, Michael

    2015-05-18

    A major difference between manmade underwater robotic vehicles (URVs) and undersea animals is the dense arrays of sensors on the body of the latter which enable them to execute extreme control of their limbs and demonstrate super-maneuverability. There is a high demand for miniaturized, low-powered, lightweight and robust sensors that can perform sensing on URVs to improve their control and maneuverability. In this paper, we present the design, fabrication and experimental testing of two types of microelectromechanical systems (MEMS) sensors that benefit the situational awareness and control of a robotic stingray. The first one is a piezoresistive liquid crystal polymer haircell flow sensor which is employed to determine the velocity of propagation of the stingray. The second one is Pb(Zr(0.52)Ti(0.48))O3 piezoelectric micro-diaphragm pressure sensor which measures various flapping parameters of the stingray's fins that are key parameters to control the robot locomotion. The polymer flow sensors determine that by increasing the flapping frequency of the fins from 0.5 to 3 Hz the average velocity of the stingray increases from 0.05 to 0.4 BL s(-1), respectively. The role of these sensors in detecting errors in control and functioning of the actuators in performing tasks like flapping at a desired amplitude and frequency, swimming at a desired velocity and direction are quantified. The proposed sensors are also used to provide inputs for a model predictive control which allows the robot to track a desired trajectory. Although a robotic stingray is used as a platform to emphasize the role of the MEMS sensors, the applications can be extended to most URVs.

  1. Rapid transfer of hierarchical microstructures onto biomimetic polymer surfaces with gradually tunable water adhesion from slippery to sticky superhydrophobicity

    Science.gov (United States)

    Chen, An-Fu; Huang, Han-Xiong

    2016-02-01

    Biomimetic superhydrophobic surfaces are generally limited to extremely high or quite low water droplet adhesion. The present work proposes flexible template replication methods for bio-inspired polypropylene (PP) surfaces with microtopographies and gradually tunable water droplet adhesion in one step using microinjection compression molding (μ-ICM). A dual-level microstructure appears on PP surfaces prepared using a flexible template. The microstructures obtained under low and high mold temperatures exhibit low-aspect-ratio (AR) micropillars with semi-spherical top and high-AR ones with conical top, resulting in the surfaces with high-adhesive hydrophobicity and low-adhesive superhydrophobicity, respectively. Further, silica nanoparticles (SNPs) coated on templates are transferred to viscous state-dominated melt during its filling in μ-ICM, and firmly adhered to the skin of the replicas, forming hierarchical microstructures on PP surfaces. The hydrophilic and hydrophobic SNPs on high-AR micropillared surfaces help achieve extremely high (petal effect) and extremely low (lotus effect) adhesion on superhydrophobic surfaces, respectively. The hybrid SNPs on low-AR micropillars change the Wenzel state-dominated surface to Cassie-Baxter state-dominated surface and preserves medium adhesion with superhydrophobicity. The proposed methods for fast and mass replication of superhydrophobic surfaces with the dual-level or hierarchical microtopography can be excellent candidates for the development of microfluidics, sensors, and labs on chip.

  2. Biomimetic Mussel Adhesive Inspired Clickable Anchors Applied to the Functionalization of Fe3O4 Nanoparticles

    NARCIS (Netherlands)

    Goldmann, Anja S.; Schoedel, Christine; Walther, Andreas; Yuan, Jiayin; Loos, Katja; Mueller, Axel H. E.; Müller, Axel H.E.

    2010-01-01

    The functionalization of magnetite (Fe3O4) nanoparticles with dopamine-derived clickable biomimetic anchors is reported. Herein, an alkyne-modified catechol-derivative is employed as the anchor, as i) the catechol-functional anchor groups possess irreversible covalent binding affinity to Fe3O4 nanop

  3. A Study on Adhesive Properties of Materials Based on Biomimetic Results of Gecko's Feet

    Institute of Scientific and Technical Information of China (English)

    Hao Zhang; Zhendong Dai; Stanislav Gorb

    2004-01-01

    Many animals have a magic ability to move or hold on ceilings and walls because of the design of their adhesive pads.The experiments were carried out to study the effects of material properties (elastic modulus EM and chemical components CC) and contact geometry (surface roughness, connecting stiffness) on their adhesive properties. The adhesion of the lowest EM samples is the highest ( 15 kPa) and the surface roughness has strong effects on adhesion and the adhesion decreases to 1.5 kPa for the highest EM samples. The adhesive forces are heavily influenced by CC of polyurethane. Surface roughness heavily influences the adhesion and when the roughness is higher than Ra 0.3 μm, the obtained adhesion of the samples is the same. The adhesion does not change with the normal forces when a sphere is used to contact with flat PU samples. But when the two matually contact surfaces are flat, the adhesion of a material increases with the normal load at first and then turns to slightly raise. The adhesion of them is the same for the contact angles from 1 to 3 degree when the samples are softly connected. But when they are adhesive hardly to each other the adhesion decreases with increase of the contact angle.

  4. Biomimetic emulsions reveal the effect of homeostatic pressure on cell-cell adhesion

    CERN Document Server

    Pontani, Lea-Laetitia; Viasnoff, Virgile; Brujic, Jasna

    2012-01-01

    Cell-cell contacts in tissues are continuously subject to mechanical forces due to homeostatic pressure and active cytoskeleton dynamics. While much is known about the molecular pathways of adhesion, the role of mechanics is less well understood. To isolate the role of pressure we present a dense packing of functionalized emulsion droplets in which surface interactions are tuned to mimic those of real cells. By visualizing the microstructure in 3D we find that a threshold compression force is necessary to overcome electrostatic repulsion and surface elasticity and establish protein-mediated adhesion. Varying the droplet interaction potential maps out a phase diagram for adhesion as a function of force and salt concentration. Remarkably, fitting the data with our theoretical model predicts binder concentrations in the adhesion areas that are similar to those found in real cells. Moreover, we quantify the adhesion size dependence on the applied force and thus reveal adhesion strengthening with increasing homeos...

  5. Biomimetic wet adhesion of viscoelastic liquid films anchored on micropatterned elastic substrates.

    Science.gov (United States)

    Patil, Sandip; Mangal, Rahul; Malasi, Abhinav; Sharma, Ashutosh

    2012-10-16

    Inspired by the natural adhesives in the toe pads of arthropods and some other animals, we explore the effectiveness and peel failure of a thin viscoelastic liquid film anchored on a micropatterned elastic surface. In particular, we focus on the role of the substrate pattern in adhesion energy of the liquid layer and in allowing its clean separation without cohesive failure. Peel tests on the microfabricated wet adhesives showed two distinct modes of adhesive (interfacial) and cohesive (liquid bulk) failures depending on the pattern dimensions. The adhesion energy of a viscoelastic liquid layer on an optimized micropatterned elastic substrate is ~3.5 times higher than that of a control flat bilayer and ~26 times higher than that of a viscoelastic film on a rigid substrate. Adhesive liquid layers anchored by narrow microchannels undergo clean, reversible adhesive failure rather than the cohesive failure seen on flat substrates. An increase in the channel width engenders cohesive failure in which droplets of the wet adhesive remain on the peeled surface. PMID:23035779

  6. Biomimetic Leukocyte Adhesion: A Review of Microfluidic and Computational Approaches and Applications

    Institute of Scientific and Technical Information of China (English)

    J.Hanzlik; E.Cretekos; K.A.Lamkin-Kennard

    2008-01-01

    Leukocyte rolling and adhesion are complex physiological processes that have received a great deal of attention over the past decade. Significant increases in the knowledge base related to how leukocytes adhere in shear flows have occurred as a result of the development of novel experimental and computational techniques. Micro- and nano-fabrication techniques have enabled the development of novel flow devices for studying leukocyte adhesion in simple and complex geometries. Improve-ments in computer technology have enabled simulations of complex flow processes to be developed. As a result of these ad-vances in knowledge related to leukocyte adhesion, numerous novel devices have been developed that mimic the leukocyte rolling and adhesion process. Examples of these devices include cell separation and enrichment devices and targeted ultrasound contrast agents. Future advances related to leukocyte rolling and adhesion processes hold great promise for advancing our knowledge of disease processes as well as development of novel therapeutic devices.

  7. 两性离子自组装仿生表面的制备、表征及抗黏附性能%Preparation, Characterization and Antibacterial Adhesion Performance of the Biomimetic Surfaces via Zwitterionic Self-assembly

    Institute of Scientific and Technical Information of China (English)

    吴雅露; 李光吉; 刘云鸿; 陈达杨

    2014-01-01

    设计与合成了磺酸甜菜碱型的两性离子化合物: N,N-二甲基氨甲酸乙酯基丙基三乙氧基硅烷磺酸内盐(SiNNS),利用红外光谱(FTIR)和氢核磁共振波谱(1 H NMR)对其分子组成与结构进行了表征.通过自组装技术将 SiNNS 分子构筑在玻璃基材表面,形成了模拟细胞外层膜的仿生表面.利用原子力显微镜(AFM)、X 光电子能谱(XPS)和接触角测量仪对表面的形貌特征、化学组成和润湿性进行了表征.以空白玻璃为对照样品,研究了这一表面的防雾性能和抗细菌黏附性能.结果表明,所制备的两性离子自组装仿生表面具有超亲水性和水下超疏油特性,其水滴接触角为9.2°,水下油滴接触角接近180°;与对照样品相比,两性离子自组装表面具有优异的防雾性与抗细菌黏附性.%A sulfobetaine zwitterionic compound, N,N-dimethylamino ethyl carbamate propyl triethoxysilane sulfonate ( SiNNS ), was designed and synthesized and its composition and molecular structure were characterized by means of FTIR and 1 H NMR spectroscopy. Furthermore, the biomimetic surface imitating the chemical features of cellular outer membrane were constructed via the self-assembly of SiNNS molecules on the hydroxylated glass surface. The morphology structure, chemical composition and wettability of the prepared bi-omimetic surface were characterized by atomic force microscopy ( AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The antifogging and antibacterial adhesion performances of the biomi-metic surface were investigated using an untreated glass surface as a control sample. The results indicate that the zwitterionic self-assembled biomimetic surface can possess superhydrophilicity with a water contact angle of 9. 2° and underwater superoleophobicity with an oil contact angle of 175. 6°. Compared to the corresponding control sample, the zwitterionic self-assembled biomimetic surface can exhibit an

  8. A New Self-Loading Locomotion Mechanism for Wall Climbing Robots Employing Biomimetic Adhesives

    Institute of Scientific and Technical Information of China (English)

    Amirpasha Peyvandi; Parviz Soroushian; Jue Lu

    2013-01-01

    A versatile locomotion mechanism is introduced and experimentally verified.This mechanism comprises four rectangular wheels (legs) with rotational phase difference which enables the application of pressure to each contacting surface for securing it to the surface using bio-inspired or pressure-sensitive adhesives.In this mechanism,the adhesives are applied to two rigid plates attached to each wheel via hinges incorporating torsional springs.The springs force the plates back to their original position after the contact with the surface is lost in the course of locomotion.The wheels are made of low-modulus elastomers,and the pressure applied during contact is controlled by the elastic modulus,geometry and phase difference of wheels.This reliable adhesion system does not rely upon gravity for adhering to surfaces,and provides the locomotion mechanism with the ability to climb walls and transition from horizontal to vertical surfaces.

  9. Biomimetic approaches for green tribology: from the lotus effect to blood flow control

    International Nuclear Information System (INIS)

    The research in Green tribology combines several areas including biomimetic tribomaterials and surfaces for controlled adhesion. Biomimetic surfaces mimic living nature and thus they are eco-friendly. The most famous biomimetic surface effect is the Lotus effect (reduction of water adhesion to a solid surface due to micro/nanostructuring of the solid surface). Several extensions of the Lotus effect have been discussed in the literature including the oleophobicity (repelling organic liquids such as oils), underwater oleophobicity to reduce fouling, and the shark skin effect (flow drag reduction due to specially oriented micro-riblets). Here we suggest a potentially important application of micro/nanostructured surfaces in the biomedical area: the micro/nanostructure controlled adhesion in blood flow. Blood is a suspension, and its adhesion properties are different from those of water and oil. For many cardiovascular applications, it is desirable to reduce stagnation and clotting of blood. Therefore, both the underwater oleophobicuity and shark-skin effect can be used. We discuss how computational fluid dynamics models can be used to investigate the structure–property relationships of surface pattern-controlled blood flow adhesion. (paper)

  10. Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

    Directory of Open Access Journals (Sweden)

    Stephan Schmidt

    2015-05-01

    Full Text Available Many biological functions at cell level are mediated by the glycocalyx, a dense carbohydrate-presenting layer. In this layer specific interactions between carbohydrate ligands and protein receptors are formed to control cell–cell recognition, cell adhesion and related processes. The aim of this work is to shed light on the principles of complex formation between surface anchored carbohydrates and receptor surfaces by measuring the specific adhesion between surface bound mannose on a concanavalin A (ConA layer via poly(ethylene glycol-(PEG-based soft colloidal probes (SCPs. Special emphasis is on the dependence of multivalent presentation and density of carbohydrate units on specific adhesion. Consequently, we first present a synthetic strategy that allows for controlled density variation of functional groups on the PEG scaffold using unsaturated carboxylic acids (crotonic acid, acrylic acid, methacrylic acid as grafting units for mannose conjugation. We showed by a range of analytic techniques (ATR–FTIR, Raman microscopy, zeta potential and titration that this synthetic strategy allows for straightforward variation in grafting density and grafting length enabling the controlled presentation of mannose units on the PEG network. Finally we determined the specific adhesion of PEG-network-conjugated mannose units on ConA surfaces as a function of density and grafting type. Remarkably, the results indicated the absence of a molecular-level enhancement of mannose/ConA interaction due to chelate- or subsite-binding. The results seem to support the fact that weak carbohydrate interactions at mechanically flexible interfaces hardly undergo multivalent binding but are simply mediated by the high number of ligand–receptor interactions.

  11. Biomimetic Cilia Based on MEMS Technology

    Institute of Scientific and Technical Information of China (English)

    Zhi-guo Zhou; Zhi-wen Liu

    2008-01-01

    A review on the research of Micro Electromechanical Systems (MEMS) technology based biomimetic cilia is presented. Biomimetic cilia, enabled by the advancement of MEMS technology, have been under dynamic development for the past decade. After a brief description of the background of cilia and MEMS technology, different biomimetic cilia applications are reviewed. Biomimetic cilia micro-actuators, including micromachined polyimide bimorph biomimetic cilia micro-actuator, electro-statically actuated polymer biomimetic cilia micro-actuator, and magnetically actuated nanorod array biomimetic cilia micro-actuator, are presented. Subsequently micromachined underwater flow biomimetic cilia micro-sensor is studied, followed by acoustic flow micro-sensor. The fabrication of these MEMS-based biomimetic cilia devices, characterization of their physical properties, and the results of their application experiments are discussed.

  12. 贻贝仿生组织粘合剂研究进展∗%Research progress of mussel inspired biomimetic adhesives

    Institute of Scientific and Technical Information of China (English)

    熊雄; 刘宗光; 屈树新; 翁杰

    2014-01-01

    在组织创伤修复中,常需要应用传统的固定材料或组织粘合剂,虽然组织粘合剂较传统的固定材料有诸多优势,但仍然不能满足临床应用的要求。海洋生物贻贝能够分泌富含多巴的蛋白质,可在潮湿环境中牢固粘附于各种材料的表面。目前,已开展了大量关于贻贝粘附机理的研究,受此优异粘附性能的启发,国内外许多课题组开展了仿生组织粘合材料的研究,并在相关领域探索其应用。介绍了贻贝足盘粘附机理及贻贝仿生粘合材料的研究现状,并展望了该领域未来的发展方向。%The application of traditional fixed materials or tissue adhesives are usually required in tissue repai-ring.Although having numerous advantages compared to traditional approaches,tissue adhesives cannot meet the require-ment of clinical application completely.Due to proteins secreted by plaque,which contain abundant of DOPA,marine mussels are able to adhere to a variety of materials firmly in the wet condition.Up to date, amounts of studies have been carried out to reveal the mechanism of mussel.Furthermore,the biomimetic ad-hesives,which component and structure were similar to those of mussel adhesive proteins,have been developed inspired by the excellent adhesion properties of mussel plaque.In this review,the mechanisms of mussel and re-lated studies of the biomimetic adhesives were introduced.The perspective studies of biomimetic adhesive mate-rials in the future were also highlighted.

  13. Adhesion of Mussel Foot Protein Mefp-5 to Mica: An Underwater Superglue†

    OpenAIRE

    Danner, Eric W.; Kan, Yajing; Hammer, Malte U.; Israelachvili, Jacob N.; Waite, J. Herbert

    2012-01-01

    Mussels have a remarkable ability to attach their holdfast, or byssus, opportunistically to a variety of substrata that are wet, saline, corroded, and/or fouled by biofilms. Mytilus edulis foot protein-5 (Mefp-5) is one of several proteins in the byssal adhesive plaque of the mussel M. edulis. The high content of 3,4 dihydroxyphenylalanine (Dopa) (~30 mol%) and its localization near the plaque-substrate interface have often prompted speculation that Mefp-5 plays a key role in adhesion. Using ...

  14. Hydrogel–fibre composites with independent control over cell adhesion to gel and fibres as an integral approach towards a biomimetic artificial ECM

    International Nuclear Information System (INIS)

    In the body, cells are surrounded by an interconnected mesh of insoluble, bioactive protein fibres to which they adhere in a well-controlled manner, embedded in a hydrogel-like highly hydrated matrix. True morphological and biochemical mimicry of this so-called extracellular matrix (ECM) remains a challenge but appears decisive for a successful design of biomimetic three-dimensional in vitro cell culture systems. Herein, an approach is presented which describes the fabrication and in vitro assessment of an artificial ECM which contains two major components, i.e. specifically biofunctionalized fibres and a semi-synthetic hyaluronic acid-based hydrogel, which allows control over cell adhesion towards both components. As proof of principle for the control of cell adhesion, RGD as well-known cell adhesive cue and the control sequence RGE are immobilized in the system. In vitro studies with primary human dermal fibroblasts were conducted to evaluate the specificity of cell adhesion and the potential of the composite system to support cell growth. Finally, one possible application example for guided cell growth is shown by the use of oriented fibres in a hydrogel matrix. (paper)

  15. Self-assembling peptide inspired by a barnacle underwater adhesive protein.

    Science.gov (United States)

    Nakano, Masahiro; Shen, Jian-Ren; Kamino, Kei

    2007-06-01

    An underwater bioadhesive generally comprises a multiprotein complex that provides a molecular basis for self-assembly. We report here a new class of self-assembling peptide inspired by a 20 kDa barnacle cement protein. Studies on the chemically synthesized 24-residue peptide have revealed that (1) it underwent irreversible self-assembly upon the addition of salt, (2) the self-assembly was started at a salt concentration close to that of seawater with noncovalent intermolecular interactions, (3) the self-assembled material resembled a macroscopic membrane of interwoven nanofilaments, (4) incubation in an alkaline pH range formed the intramolecular disulfide bond of a peptide molecule, thus triggering a conformation change of the molecule, and (5) conformational change of the building block promoted the formation of a nanofiber, resulting in the display of a three-dimensional meshlike mesoscopic structure with defined pores having a diameter of approximately 200 nm. The peptide is likely to provide a suitable basis for further development of peptide-based materials.

  16. A Robust Polyionized Hydrogel with an Unprecedented Underwater Anti-Crude-Oil-Adhesion Property.

    Science.gov (United States)

    Gao, Shoujian; Sun, Jichao; Liu, Pingping; Zhang, Feng; Zhang, Wenbin; Yuan, Shiling; Li, Jingye; Jin, Jian

    2016-07-01

    A polyionized hydrogel polymer (sodium polyacrylate-grafted poly(vinylidene fluoride) (PAAS-g-PVDF)) is fabricated via an alkaline-induced phase-inversion process. PAAS-g-PVDF coatings exhibit unprecedented anti-adhesion and self-cleaning properties to crude oils under an aqueous environment. A PAAS-g-PVDF-coated copper mesh can effectively separate a crude oil/water mixture with extremely high flux and high oil rejection driven by gravity, and is oil-fouling-free for long-term use. PMID:27159880

  17. Biomimetic design of platelet adhesion inhibitors to block integrin α2β1-collagen interactions: I. Construction of an affinity binding model.

    Science.gov (United States)

    Zhang, Lin; Sun, Yan

    2014-04-29

    Platelet adhesion on a collagen surface through integrin α2β1 has been proven to be significant for the formation of arterial thrombus. However, the molecular determinants mediating the integrin-collagen complex remain unclear. In the present study, the dynamics of integrin-collagen binding and molecular interactions were investigated using molecular dynamics (MD) simulations and molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) analysis. Hydrophobic interaction is identified as the major driving force for the formation of the integrin-collagen complex. On the basis of the MD simulation and MM-PBSA results, an affinity binding model (ABM) of integrin for collagen is constructed; it is composed of five residues, including Y157, N154, S155, R288, and L220. The ABM has been proven to capture the major binding motif contributing 84.8% of the total binding free energy. On the basis of the ABM, we expect to establish a biomimetic design strategy of platelet adhesion inhibitors, which would be beneficial for the development of potent peptide-based drugs for thrombotic diseases. PMID:24697616

  18. Control-release microcapsule of famotidine loaded biomimetic synthesized mesoporous silica nanoparticles: Controlled release effect and enhanced stomach adhesion in vitro.

    Science.gov (United States)

    Li, Jing; Wang, Hongyu; Yang, Baixue; Xu, Lu; Zheng, Nan; Chen, Hongtao; Li, Sanming

    2016-01-01

    In the present work, control-release microcapsule of famotidine (FMT) loaded biomimetic synthesized mesoporous silica nanoparticles (B-MSNs) was developed, and controlled release effect and stomach adhesion of this formulation in vitro were mainly investigated. B-MSN was previously synthesized and it was amorphous mesoporous nanoparticles with helical channels. Cytotoxicity of B-MSN was studied using human breast cancer cells (MCF-7) and the result indicated that cytotoxicity of B-MSN can be neglected. After loading FMT into B-MSN, specific surface area, pore volume and pore diameter of B-MSN were obviously reduced. In vitro dissolution test showed that B-MSN had the ability to slow down FMT release for 15 min. In order to prolong controlled release effect and remained the advantage of B-MSN (improve drug stability due to its rigid silica framework), the combined application of control-release microcapsule (using cellulose and hydroxypropyl methylcellulose K15M as excipients) with B-MSN was designed. It was obvious that newly designed formulation significantly controlled FMT release with Fickian diffusion mechanism and showed enhanced stomach adhesion in vitro, which has significant value in widening the application of B-MSN in formulation design.

  19. Adhesion

    Science.gov (United States)

    As the body moves, tissues or organs inside are normally able to shift around each other. This is because these tissues have ... occur if the adhesions cause an organ or body part to: Twist Pull ... unable to move normally The risk of forming adhesions is high ...

  20. Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

    Directory of Open Access Journals (Sweden)

    Bharat Bhushan

    2011-02-01

    Full Text Available The emerging field of biomimetics allows one to mimic biology or nature to develop nanomaterials, nanodevices, and processes which provide desirable properties. Hierarchical structures with dimensions of features ranging from the macroscale to the nanoscale are extremely common in nature and possess properties of interest. There are a large number of objects including bacteria, plants, land and aquatic animals, and seashells with properties of commercial interest. Certain plant leaves, such as lotus (Nelumbo nucifera leaves, are known to be superhydrophobic and self-cleaning due to the hierarchical surface roughness and presence of a wax layer. In addition to a self-cleaning effect, these surfaces with a high contact angle and low contact angle hysteresis also exhibit low adhesion and drag reduction for fluid flow. An aquatic animal, such as a shark, is another model from nature for the reduction of drag in fluid flow. The artificial surfaces inspired from the shark skin and lotus leaf have been created, and in this article the influence of structure on drag reduction efficiency is reviewed. Biomimetic-inspired oleophobic surfaces can be used to prevent contamination of the underwater parts of ships by biological and organic contaminants, including oil. The article also reviews the wetting behavior of oil droplets on various superoleophobic surfaces created in the lab.

  1. Researches and developments of biomimetics in tribology

    Institute of Scientific and Technical Information of China (English)

    DAI Zhendong; TONG Jin; REN Luquan

    2006-01-01

    Animals and plants have developed optimal geometric structures, smart topological materials and multi-functional surface textures with excellent tribological characteristics through the evolution of thousand millions of years and become models for tribological design. This paper puts forward the definition and fundament of biomimetic tribology, investigates the status of self-cleaning of liquid-solid interface, adhesion between animals' feet and solid surface, wear characteristics of biological surfaces and biomimetic design, as well as the friction and bionic design on liquid-solid interface. The further developments of the tribological biomimetics are discussed.

  2. Biomimetics in Tribology

    Science.gov (United States)

    Gebeshuber, I. C.; Majlis, B. Y.; Stachelberger, H.

    Science currently goes through a major change. Biology is evolving as new Leitwissenschaft, with more and more causation and natural laws being uncovered. The term `technoscience' denotes the field where science and technology are inseparably interconnected, the trend goes from papers to patents, and the scientific `search for truth' is increasingly replaced by search for applications with a potential economic value. Biomimetics, i.e. knowledge transfer from biology to technology, is a field that has the potential to drive major technical advances. The biomimetic approach might change the research landscape and the engineering culture dramatically, by the blending of disciplines. It might substantially support successful mastering of current tribological challenges: friction, adhesion, lubrication and wear in devices and systems from the meter to the nanometer scale. A highly successful method in biomimectics, the biomimicry innovation method, is applied in this chapter to identify nature's best practices regarding two key issues in tribology: maintenance of the physical integrity of a system, and permanent as well as temporary attachment. The best practices identified comprise highly diverse organisms and processes and are presented in a number of tables with detailed references.

  3. Underwater robots

    CERN Document Server

    Antonelli, Gianluca

    2014-01-01

    This book, now at the third edition, addresses the main control aspects in underwater manipulation tasks. The mathematical model with significant impact on the control strategy is discussed. The problem of controlling a 6-degrees-of-freedoms autonomous underwater vehicle is deeply investigated and a survey of fault detection/tolerant strategies for unmanned underwater vehicles is provided. Inverse kinematics, dynamic and interaction control for underwater vehicle-manipulator systems are then discussed. The code used to generate most of the numerical simulations is made available and briefly discussed.       

  4. Google™ underwater

    Science.gov (United States)

    Showstack, Randy

    2012-10-01

    The first underwater panoramic images were added to Google Maps™, the company announced on 25 September. This first “underwater Street View collection,” launched in partnership with the Caitlin Seaview Survey, provides people with the opportunity to “become the next virtual Jacques Cousteau.” For more information, see: maps.google.com/ocean.

  5. Microscopic and infrared spectroscopic comparison of the underwater adhesives produced by germlings of the brown seaweed species Durvillaea antarctica and Hormosira banksii.

    Science.gov (United States)

    Dimartino, Simone; Savory, David M; Fraser-Miller, Sara J; Gordon, Keith C; McQuillan, A James

    2016-04-01

    Adhesives from marine organisms are often the source of inspiration for the development of glues able to create durable bonds in wet environments. In this work, we investigated the adhesive secretions produced by germlings of two large seaweed species from the South Pacific, Durvillaea antarctica, also named 'the strongest kelp in the word', and its close relative Hormosira banksii The comparative analysis was based on optical and scanning electron microscopy imaging as well as Fourier transform infrared (FTIR) spectroscopy and principal component analysis (PCA). For both species, the egg surface presents peripheral vesicles which are released soon after fertilization to discharge a primary adhesive. This is characterized by peaks representative of carbohydrate molecules. A secondary protein-based adhesive is then secreted in the early developmental stages of the germlings. Energy dispersive X-ray, FTIR and PCA indicate that D. antarctica secretions also contain sulfated moieties, and become cross-linked with time, both conferring strong adhesive and cohesive properties. On the other hand, H. banksii secretions are complemented by the putative adhesive phlorotannins, and are characterized by a simple mechanism in which all constituents are released with the same rate and with no apparent cross-linking. It is also noted that the release of adhesive materials appears to be faster and more copious in D. antarctica than in H. banksii Overall, this study highlights that both quantity and quality of the adhesives matter in explaining the superior attachment ability of D. antarctica. PMID:27122179

  6. Minimally invasive restorative dentistry: a biomimetic approach.

    Science.gov (United States)

    Malterud, Mark I

    2006-08-01

    When providing dental treatment for a given patient, the practitioner should use a minimally invasive technique that conserves sound tooth structure as a clinical imperative. Biomimetics is a tenet that guides the author's practice and is generally described as the mimicking of natural life. This can be accomplished in many cases using contemporary composite resins and adhesive dental procedures. Both provide clinical benefits and support the biomimetic philosophy for treatment. This article illustrates a minimally invasive approach for the restoration of carious cervical defects created by poor hygiene exacerbated by the presence of orthodontic brackets.

  7. Underwater Ranging

    Directory of Open Access Journals (Sweden)

    S. P. Gaba

    1984-01-01

    Full Text Available The paper deals with underwater laser ranging system, its principle of operation and maximum depth capability. The sources of external noise and methods to improve signal-to-noise ratio are also discussed.

  8. Biomimetic modified clinical-grade POSS-PCU nanocomposite polymer for bypass graft applications: A preliminary assessment of endothelial cell adhesion and haemocompatibility

    International Nuclear Information System (INIS)

    Background: To date, there are no small internal diameter (< 5 mm) vascular grafts that are FDA approved for clinical use due to high failure rates from thrombosis and unwanted cell proliferation. The ideal conditions to enhance bioengineered grafts would be the blood contacting lumen of the bypass graft fully covered by endothelial cells (ECs). As a strategy towards this aim, we hypothesized that by immobilising biomolecules on the surface of the polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) nanocomposite polymers, which contain binding sites and ligands for cell surface receptors similar to extracellular matrix (ECM) will positively influence the attachment and proliferation of ECs. Since, the surface of POSS-PCU is inert and not directly suitable for immobilisation of biomolecules, plasma graft polymerisation is a suitable method to modify the surface properties ready for immobilisation and biofunctionalisation. Methods: POSS-PCU was activated by plasma treatment in air/O2 to from hydroperoxides (–OH, –OOH), and then carboxylated via plasma polymerisation of a 30% acrylic acid solution (Poly-AA) using a two-step plasma treatment (TSPT) process. Collagen type I, a major component of ECM, was covalently immobilised to mimic the ECM structures to ECs (5 mg/ml) using a two-step chemical reaction using EDC chemistry. Successful immobilisation of poly-AA and collagen on to the nanocomposites was confirmed using Toluidine Blue staining and the Bradford assay. Un-treated POSS-PCU served as a simple control. The impact of collagen grafting on the physical, mechanical and biological properties of POSS-PCU was evaluated via contact angle (θ) measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA), ECs adhesion and proliferation followed by platelet adhesion and haemolysis ratio (HR) tests. Results: Poly-AA content on each of the plasma treated nanocomposite films

  9. Biomimetic modified clinical-grade POSS-PCU nanocomposite polymer for bypass graft applications: A preliminary assessment of endothelial cell adhesion and haemocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Solouk, Atefeh [Biomedical Engineering Faculty, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Cousins, Brian G., E-mail: brian.cousins@ucl.ac.uk [Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London (United Kingdom); Mirahmadi, Fereshteh [Biomedical Engineering Faculty, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Mirzadeh, Hamid [Polymer Engineering Faculty, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Nadoushan, Mohammad Reza Jalali [Department of Pathology, School of Medicine, Shahed University, Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of); Seifalian, Alexander M. [Centre for Nanotechnology and Regenerative Medicine, Division of Surgery and Interventional Science, University College London (United Kingdom)

    2015-01-01

    Background: To date, there are no small internal diameter (< 5 mm) vascular grafts that are FDA approved for clinical use due to high failure rates from thrombosis and unwanted cell proliferation. The ideal conditions to enhance bioengineered grafts would be the blood contacting lumen of the bypass graft fully covered by endothelial cells (ECs). As a strategy towards this aim, we hypothesized that by immobilising biomolecules on the surface of the polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) nanocomposite polymers, which contain binding sites and ligands for cell surface receptors similar to extracellular matrix (ECM) will positively influence the attachment and proliferation of ECs. Since, the surface of POSS-PCU is inert and not directly suitable for immobilisation of biomolecules, plasma graft polymerisation is a suitable method to modify the surface properties ready for immobilisation and biofunctionalisation. Methods: POSS-PCU was activated by plasma treatment in air/O{sub 2} to from hydroperoxides (–OH, –OOH), and then carboxylated via plasma polymerisation of a 30% acrylic acid solution (Poly-AA) using a two-step plasma treatment (TSPT) process. Collagen type I, a major component of ECM, was covalently immobilised to mimic the ECM structures to ECs (5 mg/ml) using a two-step chemical reaction using EDC chemistry. Successful immobilisation of poly-AA and collagen on to the nanocomposites was confirmed using Toluidine Blue staining and the Bradford assay. Un-treated POSS-PCU served as a simple control. The impact of collagen grafting on the physical, mechanical and biological properties of POSS-PCU was evaluated via contact angle (θ) measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA), ECs adhesion and proliferation followed by platelet adhesion and haemolysis ratio (HR) tests. Results: Poly-AA content on each of the plasma treated nanocomposite films

  10. A highly versatile autonomous underwater vehicle with biomechanical propulsion

    NARCIS (Netherlands)

    Simons, D.G.; Bergers, M.M.C.; Henrion, S.; Hulzenga, J.I.J.; Jutte, R.W.; Pas, W.M.G.; Van Schravendijk, M.; Vercruyssen, T.G.A.; Wilken, A.P.

    2009-01-01

    An autonomous underwater vehicle with a biomechanical propulsion system is a possible answer to the demand for small, silent sensor platforms in many fields. The design of Galatea, a bio-mimetic AUV, involves four aspects: hydrodynamic shape, the propulsion, the motion control systems and payload. T

  11. Wetting, superhydrophobicity, and icephobicity in biomimetic composite materials

    Science.gov (United States)

    Hejazi, Vahid

    data are collected in terms of oleophobicity especially when underwater applications are of interest. We develop models for four-phase rough interface of underwater oleophobicity and develop a novel approach to predict the CA of organic liquid on the rough surfaces immersed in water. We investigate wetting transition on a patterned surface in underwater systems, using a phase field model. We demonstrated that roughening on an immersed solid surface can drive the transition from Wenzel to Cassie-Baxter state. This discovery improves our understanding of underwater systems and their surface interactions during the wetting phenomenon and can be applied for the development of underwater oil-repellent materials which are of interest for various applications in the water industry, and marine devices. In chapter five, we experimentally and theoretically investigate the icephobicity of composite materials. A novel comprehensive definition of icephobicity, broad enough to cover a variety of situations including low adhesion strength, delayed ice crystallization, and bouncing is determined. Wetting behavior and ice adhesion properties of various samples are theoretically and experimentally compared. We conclude superhydrophobic surfaces are not necessarily icephobic. The models are tested against the experimental data to verify the good agreement between them. The models can be used for the design of novel superhydrophobic, oleophobic, omniphobic and icephobic composite materials. Finally we conclude that creating surface micro/nanostructures using mechanical abrasion or chemical etching as well as applying low energy materials are the most simple, inexpensive, and durable techniques to create superhydrophobic, oleophobic, and icephobic materials.

  12. Arg-Gly-Asp (RGD) Modified Biomimetic Polymeric Materials

    Institute of Scientific and Technical Information of China (English)

    Xufeng NIU; Yuanliang WANG; Yanfeng LUO; Juan XIN; Yonggang LI

    2005-01-01

    The new generation of biomaterials focuses on the design of biomimetic polymeric materials that are capable of eliciting specific cellular responses and directing new tissue formation. Since Arg-Gly-Asp (RGD) sequences have been found to promote cell adhesion in 1984, numerous polymers have been functionalized with RGD peptides for tissue engineering applications. This review gave the advance in RGD modified biomimetic polymeric materials,focusing on the mechanism of RGD, the surface and bulk modification of polymer with RGD peptides and the evaluation in vitro and in vivo of the modified biomimetic materials.

  13. A biomimetic projector with high subwavelength directivity based on dolphin biosonar

    Science.gov (United States)

    Zhang, Yu; Gao, Xiaowei; Zhang, Sai; Cao, Wenwu; Tang, Liguo; Wang, Ding; Li, Yan

    2014-09-01

    Based on computed tomography of a Yangtze finless porpoise's biosonar system, a biomimetic structure was designed to include air cavity, gradient-index material, and steel outer-structure mimicking air sacs, melon, and skull, respectively. The mainlobe pressure was about three times higher, the angular resolution was one order of magnitude higher, and the effective source size was orders of magnitude larger than those of the subwavelength source without the biomimetic structure. The superior subwavelength directivity over a broad bandwidth suggests potential applications of this biomimetic projector in underwater sonar, medical ultrasonography, and other related applications.

  14. Development of a Lobster-Inspired Underwater Microrobot

    Directory of Open Access Journals (Sweden)

    Liwei Shi

    2013-01-01

    Full Text Available Biomimetic underwater microrobots are of great interest for underwater monitoring operations, such as pollution detection and video mapping in restricted underwater environments. Generally speaking, compact structure, multi‐functionality, flexibility and precise positioning are considered incompatible characteristics for underwater microrobots. Nevertheless, we have designed several novel types of bio‐inspired locomotion, using ionic polymer metal composite (IPMC and shape memory alloy (SMA actuators. We reviewed a number of previously developed underwater microrobot prototypes that were constructed to demonstrate the feasibility of these types of biomimetic locomotion. Based on these prototypes, we summarized the implemented techniques and available results for efficient and precise underwater locomotion. In order to combine compact structure, multi‐functionality, flexibility and precise positioning, we constructed a prototype of a new lobster‐like microrobot and carried out a series of experiments to evaluate its walking, rotating, floating and grasping motions. Diving/surfacing experiments were performed by electrolyzing the water around the surfaces of the actuators. Three proximity sensors were installed on the microrobot to detect an object or avoid an obstacle while walking.

  15. Biomimetic Flow Sensors

    NARCIS (Netherlands)

    Casas, J.; Liu, Chang; Krijnen, G.J.M.

    2012-01-01

    Biomimetic flow sensors are biologically inspired devices that measure the speed and direction of fluids. This survey starts by describing the role and functioning of airflow-sensing hairs in arthropods and in fishes, carries on with the biomimetic MEMS implementations, both for air and water flow s

  16. A novel soft biomimetic microrobot with two motion attitudes.

    Science.gov (United States)

    Shi, Liwei; Guo, Shuxiang; Li, Maoxun; Mao, Shilian; Xiao, Nan; Gao, Baofeng; Song, Zhibin; Asaka, Kinji

    2012-01-01

     A variety of microrobots have commonly been used in the fields of biomedical engineering and underwater operations during the last few years. Thanks to their compact structure, low driving power, and simple control systems, microrobots can complete a variety of underwater tasks, even in limited spaces. To accomplish our objectives, we previously designed several bio-inspired underwater microrobots with compact structure, flexibility, and multi-functionality, using ionic polymer metal composite (IPMC) actuators. To implement high-position precision for IPMC legs, in the present research, we proposed an electromechanical model of an IPMC actuator and analysed the deformation and actuating force of an equivalent IPMC cantilever beam, which could be used to design biomimetic legs, fingers, or fins for an underwater microrobot. We then evaluated the tip displacement of an IPMC actuator experimentally. The experimental deflections fit the theoretical values very well when the driving frequency was larger than 1 Hz. To realise the necessary multi-functionality for adapting to complex underwater environments, we introduced a walking biomimetic microrobot with two kinds of motion attitudes: a lying state and a standing state. The microrobot uses eleven IPMC actuators to move and two shape memory alloy (SMA) actuators to change its motion attitude. In the lying state, the microrobot implements stick-insect-inspired walking/rotating motion, fish-like swimming motion, horizontal grasping motion, and floating motion. In the standing state, it implements inchworm-inspired crawling motion in two horizontal directions and grasping motion in the vertical direction. We constructed a prototype of this biomimetic microrobot and evaluated its walking, rotating, and floating speeds experimentally. The experimental results indicated that the robot could attain a maximum walking speed of 3.6 mm/s, a maximum rotational speed of 9°/s, and a maximum floating speed of 7.14 mm/s. Obstacle

  17. A Novel Soft Biomimetic Microrobot with Two Motion Attitudes

    Directory of Open Access Journals (Sweden)

    Liwei Shi

    2012-12-01

    Full Text Available  A variety of microrobots have commonly been used in the fields of biomedical engineering and underwater operations during the last few years. Thanks to their compact structure, low driving power, and simple control systems, microrobots can complete a variety of underwater tasks, even in limited spaces. To accomplish our objectives, we previously designed several bio-inspired underwater microrobots with compact structure, flexibility, and multi-functionality, using ionic polymer metal composite (IPMC actuators. To implement high-position precision for IPMC legs, in the present research, we proposed an electromechanical model of an IPMC actuator and analysed the deformation and actuating force of an equivalent IPMC cantilever beam, which could be used to design biomimetic legs, fingers, or fins for an underwater microrobot. We then evaluated the tip displacement of an IPMC actuator experimentally. The experimental deflections fit the theoretical values very well when the driving frequency was larger than 1 Hz. To realise the necessary multi-functionality for adapting to complex underwater environments, we introduced a walking biomimetic microrobot with two kinds of motion attitudes: a lying state and a standing state. The microrobot uses eleven IPMC actuators to move and two shape memory alloy (SMA actuators to change its motion attitude. In the lying state, the microrobot implements stick-insect-inspired walking/rotating motion, fish-like swimming motion, horizontal grasping motion, and floating motion. In the standing state, it implements inchworm-inspired crawling motion in two horizontal directions and grasping motion in the vertical direction. We constructed a prototype of this biomimetic microrobot and evaluated its walking, rotating, and floating speeds experimentally. The experimental results indicated that the robot could attain a maximum walking speed of 3.6 mm/s, a maximum rotational speed of 9°/s, and a maximum floating speed of 7

  18. Design and Kinematics Simulation of the Propulsion Mechanism of an Unmanned Underwater Vehicle with Biomimetic Flapping Foils%仿生扑翼UUV推进机构设计及运动仿真

    Institute of Scientific and Technical Information of China (English)

    丁浩; 宋保维; 朱崎峰

    2011-01-01

    针对仿生扑翼UUV所使用的推进机构进行设计研究,在对海龟前肢运动模式分析的基础上,设计了一套二自由度仿生扑翼推进机构,该机构由两个电机分别驱动扑翼模型上下拍水及绕翼轴自身翻转,两个电机转动相互结合可以近似实现海龟前肢扑翼运动模式。对所设计推进机构进行三维建模及虚拟装配,并对其进行了运动仿真,给出了两种驱动模式下扑翼运动过程的姿态及相应的角速度和角加速度。%In this paper,the propulsion mechanism used by a flapping-foil UUV(Unmanned Underwater Vehicle) is studied.On the basis of analysing the forelimb movement patterns of turtles,a flapping-foil propulsion mechanism with two degrees of freedom is put forward,which can approximately achieve the forelimb movement patterns of turtles: fluttering up and down and overturning the wing itself,by combining its two motors′ rotating.The three-dimensional modeling and virtual assembly of the propulsion mechanism has been implemented.The kinematics simulation of the 3D assembled model has also been implemented,and the posture,the corresponding angular velocity and angular acceleration of flapping foil movement in two drive modes are given.

  19. Biomimetic thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  20. Bioinspired super-antiwetting interfaces with special liquid-solid adhesion.

    Science.gov (United States)

    Liu, Mingjie; Zheng, Yongmei; Zhai, Jin; Jiang, Lei

    2010-03-16

    Super-antiwetting interfaces, such as superhydrophobic and superamphiphobic surfaces in air and superoleophobic interfaces in water, with special liquid-solid adhesion have recently attracted worldwide attention. Through tuning surface microstructures and compositions to achieve certain solid/liquid contact modes, we can effectively control the liquid-solid adhesion in a super-antiwetting state. In this Account, we review our recent progress in the design and fabrication of these bioinspired super-antiwetting interfaces with special liquid-solid adhesion. Low-adhesion superhydrophobic surfaces are biologically inspired, typically by the lotus leaf. Wettability investigated at micro- and nanoscale reveals that the low adhesion of the lotus surface originates from the composite contact mode, a microdroplet bridging several contacts, within the hierarchical structures. Recently high-adhesion superhydrophobic surfaces have also attracted research attention. These surfaces are inspired by the surfaces of gecko feet and rose petals. Accordingly, we propose two biomimetic approaches for the fabrication of high-adhesion superhydrophobic surfaces. First, to mimic a sticky gecko's foot, we designed structures with nanoscale pores that could trap air isolated from the atmosphere. In this case, the negative pressure induced by the volume change of sealed air as the droplet is pulled away from surface can produce a normal adhesive force. Second, we constructed microstructures with size and topography similar to that of a rose petal. The resulting materials hold air gaps in their nanoscale folds, controlling the superhydrophobicity in a Wenzel state on the microscale. Furthermore, we can tune the liquid-solid adhesion on the same superhydrophobic surface by dynamically controlling the orientations of microstructures without altering the surface composition. The superhydrophobic wings of the butterfly (Morpho aega) show directional adhesion: a droplet easily rolls off the surface

  1. Optimal Sensor Layouts in Underwater Locomotory Systems

    Science.gov (United States)

    Colvert, Brendan; Kanso, Eva

    2015-11-01

    Retrieving and understanding global flow characteristics from local sensory measurements is a challenging but extremely relevant problem in fields such as defense, robotics, and biomimetics. It is an inverse problem in that the goal is to translate local information into global flow properties. In this talk we present techniques for optimization of sensory layouts within the context of an idealized underwater locomotory system. Using techniques from fluid mechanics and control theory, we show that, under certain conditions, local measurements can inform the submerged body about its orientation relative to the ambient flow, and allow it to recognize local properties of shear flows. We conclude by commenting on the relevance of these findings to underwater navigation in engineered systems and live organisms.

  2. Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface

    Directory of Open Access Journals (Sweden)

    Xia Pu

    2016-04-01

    Full Text Available Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS-embedded elastomeric stamping (PEES method. Scanning electron microscopy (SEM was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface.

  3. Underwater Sound Reference Division

    Data.gov (United States)

    Federal Laboratory Consortium — The Underwater Sound Reference Division (USRD) serves as the U.S. standardizing activity in the area of underwater acoustic measurements, as the National Institute...

  4. Experimental Investigation to the Kinematics of a Blue Spotted Ray like Underwater Propulsor

    Directory of Open Access Journals (Sweden)

    Jianhui He

    2013-08-01

    Full Text Available Engineers have long been impressed by the swimming speed and agility of fish. Their research effort has been focusing on the development of a new technique of propulsion by mimicking biological fish. The aim of the present work is to develop a biological inspired underwater propulsor that emulates the performance of bluspotted ray. We first measured the morphology and captured the movement of a real bluespotted ray to provide some useful references for biomimetic mechanism design. By virtue of the modular and reconfigurable design concept, a bluspotted ray like underwater propulsor was considered and developed. An experiment system was set up to investigate the effect of various kinematic parameters including frequency, amplitude, wavelength on the propulsion velocity, thrust and efficiency of the fish robot. The results show that the designed biomimetic underwater propulsor is able to propel itself effectively.

  5. First insights into the biochemistry of tube foot adhesive from the sea urchin Paracentrotus lividus (Echinoidea, Echinodermata).

    Science.gov (United States)

    Santos, R; da Costa, G; Franco, C; Gomes-Alves, P; Flammang, P; Coelho, A V

    2009-01-01

    Sea urchins are common inhabitants of wave-swept shores. To withstand the action of waves, they rely on highly specialized independent adhesive organs, the adoral tube feet. The latter are extremely well-designed for temporary adhesion being composed by two functional subunits: (1) an apical disc that produces an adhesive secretion to fasten the sea urchin to the substratum, as well as a deadhesive secretion to allow the animal to move and (2) a stem that bears the tensions placed on the animal by hydrodynamism. Despite their technological potential for the development of new biomimetic underwater adhesives, very little is known about the biochemical composition of sea urchin adhesives. A characterization of sea urchin adhesives is presented using footprints. The latter contain inorganic residues (45.5%), proteins (6.4%), neutral sugars (1.2%), and lipids (2.5%). Moreover, the amino acid composition of the soluble protein fraction revealed a bias toward six amino acids: glycine, alanine, valine, serine, threonine, and asparagine/aspartic acid, which comprise 56.8% of the total residues. In addition, it also presents higher levels of proline (6.8%) and half-cystine (2.6%) than average eukaryotic proteins. Footprint insolubility was partially overcome using strong denaturing and reducing buffers, enabling the visualization of 13 proteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The conjugation of mass spectrometry with homology-database search allowed the identification of six proteins: alpha and beta tubulin, actin, and histones H2B, H3, H2A, and H4, whose location and function in the adhesive are discussed but require further investigation. For the remaining unidentified proteins, five de novo-generated peptide sequences were found that were not present in the available protein databases, suggesting that they might be novel or modified proteins. PMID:19221839

  6. Acoustic beam control in biomimetic projector via velocity gradient

    Science.gov (United States)

    Gao, Xiaowei; Zhang, Yu; Cao, Wenwu; Dong, Erqian; Song, Zhongchang; Li, Songhai; Tang, Liguo; Zhang, Sai

    2016-07-01

    A biomimetic projector (BioP) based on computerized tomography of pygmy sperm whale's biosonar system has been designed using gradient-index (GRIN) material. The directivity of this BioP device was investigated as function of frequency and the velocity gradient of the GRIN material. A strong beam control over a broad bandwidth at the subwavelength scale has been achieved. Compared with a bare subwavelength source, the main lobe pressure of the BioP is about five times as high and the angular resolution is one order of magnitude better. Our results indicate that this BioP has excellent application potential in miniaturized underwater sonars.

  7. Blind equalization for underwater communications

    NARCIS (Netherlands)

    Blom, Koen Cornelis Hubertus

    2014-01-01

    Underwater wireless (sensor) networks would vastly improve man's ability to explore and exploit remote aquatic environments. Despite underwater sensor and vehicle technology being relatively mature, underwater communications is still a major challenge. The most challenging characteristics of the und

  8. Biomimetic sensor design

    Science.gov (United States)

    Lee, Ju Hun; Jin, Hyo-Eon; Desai, Malav S.; Ren, Shuo; Kim, Soyoun; Lee, Seung-Wuk

    2015-11-01

    Detection of desired target chemicals in a sensitive and selective manner is critically important to protect human health, environment and national security. Nature has been a great source of inspiration for the design of sensitive and selective sensors. In this mini-review, we overview the recent developments in bio-inspired sensor development. There are four major components of sensor design: design of receptors for specific targets; coating materials to integrate receptors to transducing machinery; sensitive transducing of signals; and decision making based on the sensing results. We discuss the biomimetic methods to discover specific receptors followed by a discussion about bio-inspired nanocoating material design. We then review the recent developments in phage-based bioinspired transducing systems followed by a discussion of biomimetic pattern recognition-based decision making systems. Our review will be helpful to understand recent approaches to reverse-engineer natural systems to design specific and sensitive sensors.

  9. Biomimetic hydrogel materials

    Science.gov (United States)

    Bertozzi, Carolyn; Mukkamala, Ravindranath; Chen, Qing; Hu, Hopin; Baude, Dominique

    2000-01-01

    Novel biomimetic hydrogel materials and methods for their preparation. Hydrogels containing acrylamide-functionalized carbohydrate, sulfoxide, sulfide or sulfone copolymerized with a hydrophilic or hydrophobic copolymerizing material selected from the group consisting of an acrylamide, methacrylamide, acrylate, methacrylate, vinyl and a derivative thereof present in concentration from about 1 to about 99 wt %. and methods for their preparation. The method of use of the new hydrogels for fabrication of soft contact lenses and biomedical implants.

  10. Underwater attachment using hairs: the functioning of spatula and sucker setae from male diving beetles

    OpenAIRE

    Chen, Ying; Shih, Ming-Chih; Wu, Ming-Huang; Yang, En-Cheng; Chi, Kai-Jung

    2014-01-01

    Males of Dytiscinae beetles use specialized adhesive setae to adhere to female elytra during underwater courtship. This coevolution of male setae and female elytra has attracted much attention since Darwin. However, there has been little examination of their biomechanical functioning despite increasing knowledge on biofibrillar adhesion. Here, we report and compare, for the first time, the mechanisms of underwater attachment using two hair types, the primitive spatula and derived ‘passive’ su...

  11. Underwater Acoustic Networking Techniques

    CERN Document Server

    Otnes, Roald; Casari, Paolo; Goetz, Michael; Husøy, Thor; Nissen, Ivor; Rimstad, Knut; van Walree, Paul; Zorzi, Michele

    2012-01-01

    This literature study presents an overview of underwater acoustic networking. It provides a background and describes the state of the art of all networking facets that are relevant for underwater applications. This report serves both as an introduction to the subject and as a summary of existing protocols, providing support and inspiration for the development of network architectures.

  12. Underwater Scene Composition

    Science.gov (United States)

    Kim, Nanyoung

    2009-01-01

    In this article, the author describes an underwater scene composition for elementary-education majors. This project deals with watercolor with crayon or oil-pastel resist (medium); the beauty of nature represented by fish in the underwater scene (theme); texture and pattern (design elements); drawing simple forms (drawing skill); and composition…

  13. Biomimetic multifunctional surfaces inspired from animals.

    Science.gov (United States)

    Han, Zhiwu; Mu, Zhengzhi; Yin, Wei; Li, Wen; Niu, Shichao; Zhang, Junqiu; Ren, Luquan

    2016-08-01

    Over millions of years, animals have evolved to a higher intelligent level for their environment. A large number of diverse surface structures on their bodies have been formed to adapt to the extremely harsh environment. Just like the structural diversity existed in plants, the same also applies true in animals. Firstly, this article provides an overview and discussion of the most common functional surface structures inspired from animals, such as drag reduction, noise reduction, anti-adhesion, anti-wear, anti-erosion, anti-fog, water capture, and optical surfaces. Then, some typical characteristics of morphologies, structures, and materials of the animal multifunctional surfaces were discussed. The adaptation of these surfaces to environmental conditions was also analyzed. It mainly focuses on the relationship between their surface functions and their surface structural characteristics. Afterwards, the multifunctional mechanisms or principles of these surfaces were discussed. Models of these structures were provided for the development of structure materials and machinery surfaces. At last, fabrication techniques and existing or potential technical applications inspired from biomimetic multifunctional surfaces in animals were also discussed. The application prospects of the biomimetic functional surfaces are very broad, such as civil field of self-cleaning textile fabrics and non-stick pots, ocean field of oil-water separation, sports field of swimming suits, space development field of lens arrays. PMID:27085632

  14. Biomimetic magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Michael T. Klem

    2005-09-01

    Full Text Available Magnetic nanoparticles are of considerable interest because of their potential use in high-density memory devices, spintronics, and applications in diagnostic medicine. The conditions for synthesis of these materials are often complicated by their high reaction temperatures, costly reagents, and post-processing requirements. Practical applications of magnetic nanoparticles will require the development of alternate synthetic strategies that can overcome these impediments. Biomimetic approaches to materials chemistry have provided a new avenue for the synthesis and assembly of magnetic nanomaterials that has great potential for overcoming these obstacles.

  15. Femtosecond Laser Induced Underwater Superoleophobic Surfaces

    Directory of Open Access Journals (Sweden)

    Yong Jiale

    2015-01-01

    Full Text Available Femtosecond laser microfabrication has been recently utilized in interface science to modify the liquid wettability of solid surfaces. Silicon surface with hierarchical micro/nanostructure is fabricated by a femtosecond laser. Similar to the fish’s scales, the laser-induced surface shows superhydrophilicity in air and superoleophobicity underwater. The oil contact angles can reach up to 159.4 ± 1° for the 1,2-dichloroethane droplets in water. Besides, the surface exhibits ultralow oil-adhesion. In the oil/water/solid three-phase system, water can be trapped in the hierarchical rough structure and forms a repulsive oil layer according to underwater Cassie’s theory. The contact area between the asprepared surface and oil droplet is significantly reduced, resulting in superoleophobicity and ultralow oil-adhesion in water. In addition, transparent underwater superoleophobic and anti-oil surfaces are achieved on silica glass surfaces by femtosecond laser ablation. This transparent property is attributed to the presence of the water environment because scattering and refraction are effectively weakened. The presented method is simple and can accurately control the processing location, which may have widely potential applications in, for instance, microfluidics, biotechnologies, and antifouling coatings.

  16. Characterization of the structure and composition of gecko adhesive setae

    OpenAIRE

    Rizzo, N. W.; Gardner, K.H.; Walls, D.J; Keiper-Hrynko, N.M; Ganzke, T.S; Hallahan, D.L

    2005-01-01

    The ability of certain reptiles to adhere to vertical (and hang from horizontal) surfaces has been attributed to the presence of specialized adhesive setae on their feet. Structural and compositional studies of such adhesive setae will contribute significantly towards the design of biomimetic fibrillar adhesive materials. The results of electron microscopy analyses of the structure of such setae are presented, indicating their formation from aggregates of proteinaceous fibrils held together b...

  17. Underwater wireless communication system

    Energy Technology Data Exchange (ETDEWEB)

    Goh, J H; Shaw, A; Al-Shamma' a, A I, E-mail: j.h.goh@2006.ljmu.ac.u [Liverpool John Moores University, General Engineering Research Institute (GERI), RF and Microwave Group, Byrom Street, Liverpool, L3 3AF (United Kingdom)

    2009-07-01

    Underwater communication has a range of applications including remotely operated vehicle (ROV) and autonomous underwater vehicle (AUV) communication and docking in the offshore industry. Current underwater transmission techniques is primarily utilise sound waves for large distance at lower frequencies and the velocity of sound in water is approximately 1500m/s the resultant communications have problems with multi-path propagation and low bandwidth problems. The use of electromagnetic (EM) techniques underwater has largely been overlooked because of the attenuation due to the conductivity of seawater. However, for short range applications, the higher frequencies and much higher velocity can prove advantageous. This paper will outline a project which will utilise recent investigations that demonstrate EM wave propagation up to the MHz frequency range is possible in seawater.

  18. Smelling and Tasting Underwater.

    Science.gov (United States)

    Atema, Jelle

    1980-01-01

    Discusses differences between smell and taste, comparing these senses in organisms in aquatic and terrestrial environments. Describes the chemical environment underwater and in air, differences in chemoreceptors to receive stimuli, and the organs, brain, and behavior involved in chemoreception. (CS)

  19. Underwater wireless communication system

    International Nuclear Information System (INIS)

    Underwater communication has a range of applications including remotely operated vehicle (ROV) and autonomous underwater vehicle (AUV) communication and docking in the offshore industry. Current underwater transmission techniques is primarily utilise sound waves for large distance at lower frequencies and the velocity of sound in water is approximately 1500m/s the resultant communications have problems with multi-path propagation and low bandwidth problems. The use of electromagnetic (EM) techniques underwater has largely been overlooked because of the attenuation due to the conductivity of seawater. However, for short range applications, the higher frequencies and much higher velocity can prove advantageous. This paper will outline a project which will utilise recent investigations that demonstrate EM wave propagation up to the MHz frequency range is possible in seawater.

  20. A Biomimetic Haptic Sensor

    Directory of Open Access Journals (Sweden)

    Ben Mitchinson

    2008-11-01

    Full Text Available The design and implementation of the periphery of an artificial whisker sensory system is presented. It has been developed by adopting a biomimetic approach to model the structure and function of rodent facial vibrissae. The artificial vibrissae have been formed using composite materials and have the ability to be actively moved or whisked. The sensory structures at the root of real vibrissae has been modelled and implemented using micro strain gauges and Digital Signal Processors. The primary afferents and vibrissal trigeminal ganglion have been modelled using empirical data taken from electrophysiological measurements, and implemented in real-time using a Field Programmable Gate Array. Pipelining techniques were employed to maximise the utility of the FPGA hardware. The system is to be integrated into a more complete whisker sensory model, including neural structures within the central nervous system, which can be used to orient a mobile robot.

  1. Biomimetic thin film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  2. Abdominal Adhesions

    Science.gov (United States)

    ... adhesions? Abdominal adhesions can cause intestinal obstruction and female infertility—the inability to become pregnant after a year of trying. Abdominal adhesions can lead to female infertility by preventing fertilized eggs from reaching the uterus, ...

  3. BIOMIMETIC STRATEGIES IN ORGANIC SYNTHESIS. TERPENES

    OpenAIRE

    V. Kulcitki

    2012-01-01

    The current paper represents an outline of the selected contributions to the biomimetic procedures and approaches for the synthesis of terpenes with complex structure and diverse functionalisation pattern. These include homologation strategies, cyclisations, rearrangements, as well as biomimetic remote functionalisations.

  4. Multiscale mechanics and physics of nature’s dry adhesion systems

    OpenAIRE

    Karlsson, Nils

    2012-01-01

    Dry adhesion systems adhere via physical bonds without any significant contribution from a liquid medium. In nature, these systems are found among the footpads of spiders, lizards and many other small animals, with high adhesion force, low detachment force and elfcleaning properties. These features are highly interesting for biomimetic man-made adhesives. Heavy animals have an adhesion force much higher than its muscle force, and to enable detachment, they have evolved a functional surface wi...

  5. Improved Bio-inspired Artificial Gecko Adhesive by Using Hierarchical Fibrillar Structures

    OpenAIRE

    Li, Yasong

    2014-01-01

    Geckos are well known for being rapid climbers that have long existed in nature. The reversible and reusable adhesive on their feet intrigues scientists to explore a bio-mimetic adhesive, which inherits the adhesion properties of the gecko’s adhesives. Recent advances in electron microscopy reveal the secret of gecko’s climbing ability: there are hierarchical fibrillar structures branching from the skin of their climbing feet. Sizes of these hierarchical fibrils range from micrometer to nanom...

  6. Trends in underwater warfare : From an underwater acoustics perspective

    NARCIS (Netherlands)

    Ort, C.M.; Driessen, F.P.G.

    2002-01-01

    Technological developments concerning underwater systems for Anti Submarine Warfare (ASW) and Mine Counter Measures (MCM) are directed at optimally countering the underwater threat in the near future. Countering the existing underwater threat is already extremely difficult, but there are several tre

  7. Biomimetic Production of Hydrogen

    Science.gov (United States)

    Gust, Devens

    2004-03-01

    The basic reaction for hydrogen generation is formation of molecular hydrogen from two electrons and two protons. Although there are many possible sources for the protons and electrons, and a variety of mechanisms for providing the requisite energy for hydrogen synthesis, the most abundant and readily available source of protons and electrons is water, and the most attractive source of energy for powering the process is sunlight. Not surprisingly, living systems have evolved to take advantage of these sources for materials and energy. Thus, biology provides paradigms for carrying out the reactions necessary for hydrogen production. Photosynthesis in green plants uses sunlight as the source of energy for the oxidation of water to give molecular oxygen, protons, and reduction potential. Some photosynthetic organisms are capable of using this reduction potential, in the form of the reduced redox protein ferredoxin, to reduce protons and produce molecular hydrogen via the action of an hydrogenase enzyme. A variety of other organisms metabolize the reduced carbon compounds that are ultimately the major products of photosynthesis to produce molecular hydrogen. These facts suggest that it might be possible to use light energy to make molecular hydrogen via biomimetic constructs that employ principles similar to those used by natural organisms, or perhaps with hybrid "bionic" systems that combine biomimetic materials with natural enzymes. It is now possible to construct artificial photosynthetic systems that mimic some of the major steps in the natural process.(1) Artificial antennas based on porphyrins, carotenoids and other chromophores absorb light at various wavelengths in the solar spectrum and transfer the harvested excitation energy to artificial photosynthetic reaction centers.(2) In these centers, photoinduced electron transfer uses the energy from light to move an electron from a donor to an acceptor moiety, generating a high-energy charge-separated state

  8. Artificial lateral line with biomimetic neuromasts to emulate fish sensing

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yingchen; Chen Nannan; Tucker, Craig; Hu Huan; Liu Chang [Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208 (United States); Nguyen, Nam; Lockwood, Michael; Jones, Douglas L [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Bleckmann, Horst, E-mail: changliu@northwestern.ed, E-mail: dl-jones@uiuc.ed [Institut fuer Zoologie, Universitaet Bonn, Poppelsdorfer Schloss, D-53115 Bonn (Germany)

    2010-03-15

    Hydrodynamic imaging using the lateral line plays a critical role in fish behavior. To engineer such a biologically inspired sensing system, we developed an artificial lateral line using MEMS (microelectromechanical system) technology and explored its localization capability. Arrays of biomimetic neuromasts constituted an artificial lateral line wrapped around a cylinder. A beamforming algorithm further enabled the artificial lateral line to image real-world hydrodynamic events in a 3D domain. We demonstrate that the artificial lateral line system can accurately localize an artificial dipole source and a natural tail-flicking crayfish under various conditions. The artificial lateral line provides a new sense to man-made underwater vehicles and marine robots so that they can sense like fish.

  9. Artificial lateral line with biomimetic neuromasts to emulate fish sensing

    International Nuclear Information System (INIS)

    Hydrodynamic imaging using the lateral line plays a critical role in fish behavior. To engineer such a biologically inspired sensing system, we developed an artificial lateral line using MEMS (microelectromechanical system) technology and explored its localization capability. Arrays of biomimetic neuromasts constituted an artificial lateral line wrapped around a cylinder. A beamforming algorithm further enabled the artificial lateral line to image real-world hydrodynamic events in a 3D domain. We demonstrate that the artificial lateral line system can accurately localize an artificial dipole source and a natural tail-flicking crayfish under various conditions. The artificial lateral line provides a new sense to man-made underwater vehicles and marine robots so that they can sense like fish.

  10. Biomimetic implant coatings.

    Science.gov (United States)

    Eisenbarth, E; Velten, D; Breme, J

    2007-02-01

    Biomaterials and tissue engineering technologies are becoming increasingly important in biomedical practice, particularly as the population ages. Cellular responses depend on topographical properties of the biomaterial at the nanometer scale. Structures on biomaterial surfaces are used as powerful tools to influence or even control interactions between implants and the biological system [; ]. The influence of nanometer sized surface structures on osteoblastlike cell interactions was tested with niobium oxide coatings on polished titanium slices (cp-Ti grade 2). The aim of the study was to investigate the influence of nanoscopic surface structures on osteoblast interactions in order to support collagen I production and cell adhesion. The coatings were done by means of the sol-gel process. The surface structure was adjusted by annealing of the metaloxide ceramic coatings due to temperature depended crystal growth. The applied annealing temperatures were 450, 550 and 700 degrees C for 1 h, corresponding to Ra-numbers of 7, 15 and 40 nm. The surfaces were characterized by means of AFM, DTA/TG, diffractometry and white light interferometry. The cell reactions were investigated concerning adhesion kinetics, migration, spreading, cell adhesion, and collagen I synthesis. The smooth surface (Ra=7 nm) resulted in the fastest cell anchorage and cell migration. The closest cell adhesion was reached with the surface structure of Ra=15 nm. The roughest surface (Ra=40 nm) impedes the cell migration as well as a proper spreading of the cells. The best results concerning cell adhesion and spreading was reached with an intermediate surface roughness of Ra=15 nm of the niobium oxide coating on cp-titanium slices. PMID:16828342

  11. Securing underwater wireless communication networks

    OpenAIRE

    Domingo Aladrén, Mari Carmen

    2011-01-01

    Underwater wireless communication networks are particularly vulnerable to malicious attacks due to the high bit error rates, large and variable propagation delays, and low bandwidth of acoustic channels. The unique characteristics of the underwater acoustic communication channel, and the differences between underwater sensor networks and their ground-based counterparts require the development of efficient and reliable security mechanisms. In this article, a compl...

  12. Resources for Underwater Robotics Education

    Science.gov (United States)

    Wallace, Michael L.; Freitas, William M.

    2016-01-01

    4-H clubs can build and program underwater robots from raw materials. An annotated resource list for engaging youth in building underwater remotely operated vehicles (ROVs) is provided. This article is a companion piece to the Research in Brief article "Building Teen Futures with Underwater Robotics" in this issue of the "Journal of…

  13. Advanced underwater lift device

    Science.gov (United States)

    Flanagan, David T.; Hopkins, Robert C.

    1993-01-01

    Flexible underwater lift devices ('lift bags') are used in underwater operations to provide buoyancy to submerged objects. Commercially available designs are heavy, bulky, and awkward to handle, and thus are limited in size and useful lifting capacity. An underwater lift device having less than 20 percent of the bulk and less than 10 percent of the weight of commercially available models was developed. The design features a dual membrane envelope, a nearly homogeneous envelope membrane stress distribution, and a minimum surface-to-volume ratio. A proof-of-concept model of 50 kg capacity was built and tested. Originally designed to provide buoyancy to mock-ups submerged in NASA's weightlessness simulators, the device may have application to water-landed spacecraft which must deploy flotation upon impact, and where launch weight and volume penalties are significant. The device may also be useful for the automated recovery of ocean floor probes or in marine salvage applications.

  14. Fabrication of Biomimetic Water Strider Legs Covered with Setae

    Institute of Scientific and Technical Information of China (English)

    Zhi-guo Zhou; Zhi-wen Liu

    2009-01-01

    Water striders have remarkable water-repellent legs that enable them to stand effortlessly and move quickly on water. Fluid physics indicates this feature is due to a surface-tension effect caused by the special hierarchical structure of the legs, which are covered with a large number of inclined setae with fine nanogrooves inducing water resistance. This inspires us to fabricate special water-repellent structure on functional surfaces through the cooperation between the surface treatment and the surface micro- and nanostructures, which may bring great advantages in a wide variety of applications. In this paper we present a procedure for fabricating biomimetic water strider legs covered with setae using Polycarbonate Track-Etched (PCTE) membranes as templates. By choosing appropriate membrane lengths, diameters, pitches and densities of the setae, the biomimetic legs can be fabricated conveniently and at a low cost. Furthermore we investigated the relationship between stiffness of the molding materials, high aspect ratio and density, which affect the fidelity of fabrication and self adhesion, to optimize the stability of setae. The knowledge we gained from this study will offer important insights into the biomimetic design and fabrication of water strider setae.

  15. Rational design and nanofabrication of gecko-inspired fibrillar adhesives.

    Science.gov (United States)

    Hu, Shihao; Xia, Zhenhai

    2012-08-20

    Gecko feet integrate many intriguing functions such as strong adhesion, easy detachment, and self-cleaning. Mimicking gecko toe pad structure leads to the development of new types of fibrillar adhesives useful for various applications. In this Concept article, in addition to the design of adhesive mimics by replicating gecko geometric features, we show a new trend of rational design by adding other physical, chemical, and biological principles on to the geometric merits, for enhancing robustness, responsive control, and durability. Current challenges and future directions are highlighted in the design and nanofabrication of biomimetic fibrillar adhesives.

  16. [Biomimetic sensors in biomedical research].

    Science.gov (United States)

    Gayet, Landry; Lenormand, Jean-Luc

    2015-01-01

    The recent research on both the synthesis of membrane proteins by cell-free systems and the reconstruction of planar lipid membranes, has led to the development of a cross-technology to produce biosensors or filters. Numerous biomimetic membranes are currently being standardized and used by the industry, such as filters containing aquaporin for water desalination, or used in routine at the laboratory scale, for example the bacteriorhodopsin as a light sensor. In the medical area, several fields of application of these biomimetic membranes are under consideration today, particularly for the screening of therapeutic molecules and for the developing of new tools in diagnosis, patient monitoring and personalized medicine. PMID:26152170

  17. Underwater Navigation using Pseudolite

    Directory of Open Access Journals (Sweden)

    Krishneshwar Tiwary

    2011-07-01

    Full Text Available Using pseudolite or pseudo satellite, a proven technology for ground and space applications for the augmentation of GPS, is proposed for underwater navigation. Global positioning systems (GPS like positioning for underwater system, needs minimum of four pseudolite-ranging signals for pseudo-range and accumulated delta range measurements. Using four such measurements and using the models of underwater attenuation and delays, the navigation solution can be found. However, for application where the one-way ranging does not give good accuracy, alternative algorithms based upon the bi-directional and self-difference ranging is proposed using selfcalibrated pseudolite array algorithm. The hardware configuration is proposed for pseudolite transceiver for making the self-calibrated array. The pseudolite array, fixed or moored under the sea, can give position fixing similar to GPS for underwater applications.Defence Science Journal, 2011, 61(4, pp.331-336, DOI:http://dx.doi.org/10.14429/dsj.61.1087

  18. Bio-inspired hierarchical polymer fiber-carbon nanotube adhesives.

    Science.gov (United States)

    Rong, Zhuxia; Zhou, Yanmin; Chen, Bingan; Robertson, John; Federle, Walter; Hofmann, Stephan; Steiner, Ullrich; Goldberg-Oppenheimer, Pola

    2014-03-01

    Hierarchical pillar arrays consisting of micrometer-sized polymer setae covered by carbon nanotubes are engineered to deliver the role of spatulae, mimicking the fibrillar adhesive surfaces of geckos. These biomimetic structures conform well and achieve better attachment to rough surfaces, providing a new platform for a variety of applications.

  19. Underwater attachment using hairs: the functioning of spatula and sucker setae from male diving beetles.

    Science.gov (United States)

    Chen, Ying; Shih, Ming-Chih; Wu, Ming-Huang; Yang, En-Cheng; Chi, Kai-Jung

    2014-08-01

    Males of Dytiscinae beetles use specialized adhesive setae to adhere to female elytra during underwater courtship. This coevolution of male setae and female elytra has attracted much attention since Darwin. However, there has been little examination of their biomechanical functioning despite increasing knowledge on biofibrillar adhesion. Here, we report and compare, for the first time, the mechanisms of underwater attachment using two hair types, the primitive spatula and derived 'passive' sucker, found in male diving beetles. Results from interspecific scaling of protarsal palettes and adhesion by single seta suggest better performance in the later-evolved circular (sucker) setae. Spatula setae with a modified shallow sucker and channels use the combined mechanisms of suction and viscous resistance for adhesion. Velocity-dependent adhesion provides sufficient control for resisting the female's erratic movements while also detaching easily through slow peeling. Direction-dependent shear resistance helps reorient setae surfaces into a preferred direction for effective adhesion. Seta deformation using different mechanisms for circular and spatula setae reduces the force that is transmitted to the contact interface. A softer spring in spatula setae explains their adhesion at lower preloads and assists in complete substrate contact. Attachment mechanisms revealed in adhesive setae with modified spatula and passive suckers provide insights for bioinspired designs of underwater attachment devices. PMID:24920108

  20. Bio-mimetic Flow Control

    Science.gov (United States)

    Choi, Haecheon

    2009-11-01

    Bio-mimetic engineering or bio-mimetics is the application of biological methods and systems found in nature to the study and design of engineering systems and modern technology (from Wikipedia). The concept itself is old, but successful developments have been made recently, especially in the research field of flow control. The objective of flow control based on the bio-mimetic approach is to develop novel concepts for reducing drag, increasing lift and enhancing aerodynamic performance. For skin friction reduction, a few ideas have been suggested such as the riblet from shark, compliant surface from dolphin, microbubble injection and multiple front-body curvature from penguin, and V-shaped protrusion from sailfish. For form drag reduction, several new attempts have been also made recently. Examples include the V-shaped spanwise grooves from saguaro cactus, overall shape of box fish, longitudinal grooves on scallop shell, bill of swordfish, hooked comb on owl wing, trailing-edge protrusion on dragonfly wing, and fillet. For the enhancement of aerodynamic performance, focuses have been made on the birds, fish and insects: e.g., double layered feather of landing bird, leading-edge serration of humpback-whale flipper, pectoral fin of flying fish, long tail on swallowtail-butterfly wing, wing flapping motion of dragonfly, and alula in birds. Living animals adapt their bodies to better performance in multi purposes, but engineering requires single purpose in most cases. Therefore, bio-mimetic approaches often produce excellent results more than expected. However, they are sometimes based on people's wrong understanding of nature and produce unwanted results. Successes and failures from bio-mimetic approaches in flow control will be discussed in the presentation.

  1. Adhesive Categories

    DEFF Research Database (Denmark)

    Lack, Stephen; Sobocinski, Pawel

    2003-01-01

    We introduce adhesive categories, which are categories with structure ensuring that pushouts along monomorphisms are well-behaved. Many types of graphical structures used in computer science are shown to be examples of adhesive categories. Double-pushout graph rewriting generalises well...... to rewriting on arbitrary adhesive categories....

  2. Adhesive Categories

    DEFF Research Database (Denmark)

    Lack, Stephen; Sobocinski, Pawel

    2004-01-01

    We introduce adhesive categories, which are categories with structure ensuring that pushouts along monomorphisms are well-behaved. Many types of graphical structures used in computer science are shown to be examples of adhesive categories. Double-pushout graph rewriting generalises well...... to rewriting on arbitrary adhesive categories....

  3. Adhesive complex coacervate inspired by the sandcastle worm as a sealant for fetoscopic defects

    Science.gov (United States)

    Kaur, Sarbjit

    Inspired by the Sandcastle Worm, biomimetic of the water-borne adhesive was developed by complex coacervation of the synthetic copolyelectrolytes, mimicking the chemistries of the worm glue. The developed underwater adhesive was designed for sealing fetal membranes after fetoscopic surgery in twin-to-twin transfusion syndrome (TTTS) and sealing neural tissue of a fetus in aminiotic sac for spina bifida condition. Complex coacervate with increased bond strength was created by entrapping polyethylene glycol diacrylate (PEG-dA) monomer within the cross-linked coacervate network. Maximum shear bond strength of ~ 1.2 MPa on aluminum substrates was reached. The monomer-filled coacervate had complex flow behavior, thickening at low shear rates and then thinning suddenly with a 16-fold drop in viscosity at shear rates near 6 s-1. The microscale structure of the complex coacervates resembled a three-dimensional porous network of interconnected tubules. This complex coacervate adhesive was used in vitro studies to mimic the uterine wall-fetal membrane interface using a water column with one end and sealed with human fetal membranes and poultry breast, and a defect was created with an 11 French trocar. The coacervate adhesive in conjunction with the multiphase adhesive was used to seal the defect. The sealant withstood an additional traction of 12 g for 30-60 minutes and turbulence of the water column without leakage of fluid or slippage. The adhesive is nontoxic when in direct contact with human fetal membranes in an organ culture setting. A stable complex coacervate adhesive for long-term use in TTTS and spina bifida application was developed by methacrylating the copolyelectrolytes. The methacrylated coacervate was crosslinked chemically for TTTS and by photopolymerization for spina bifida. Tunable mechanical properties of the adhesive were achieved by varying the methacrylation of the polymers. Varying the amine to phosphate (A/P) ratio in the coacervate formation

  4. Underwater Radio Communication

    OpenAIRE

    Fjuk, Per Øyvind Eid

    2013-01-01

    In subsea applications, there is a growing demand for high-speed wireless communication links for transmitting data between different equipment. Radio communication is constrained by the high attenuation in seawater. Only a very short range is achievable, even at low frequencies. In this thesis an independent, battery-driven radio frequency transmitter is developed and tested to investigate the properties of, and prove the concept of underwater radio communication. The transmitter is made on ...

  5. Mechanics of underwater noise

    CERN Document Server

    Ross, Donald

    1976-01-01

    Mechanics of Underwater Noise elucidates the basic mechanisms by which noise is generated, transmitted by structures and radiated into the sea. Organized into 10 chapters, this book begins with a description of noise, decibels and levels, significance of spectra, and passive sonar equation. Subsequent chapters discuss sound waves in liquids; acoustic radiation fundamentals; wind-generated ocean ambient noise; vibration isolation and structural damping; and radiation by plate flexural vibrations. Other chapters address cavitation, propeller cavitation noise, radiation by fluctuating-force (dipo

  6. Underwater Gliders: A Review

    Directory of Open Access Journals (Sweden)

    Javaid Muhammad Yasar

    2014-07-01

    Full Text Available Underwater gliders are a type of underwater vehicle that transverse the oceans by shifting its buoyancy, during which its wings develop a component of the downward motion in the horizontal plane, thus producing a forward force. They are primarily used in oceanography sensing and data collection and play an important role in ocean research and development. Although there have been considerable developments in these gliders since the development of the first glider concept in 1989, to date, no review of these gliders have been done. This paper reviews existing underwater gliders, with emphasis on their respective working principles, range and payload capacity. All information on gliders available in the public domain or published in literature from the year 2000-2013 was reviewed. The majority of these gliders have an operational depth of 1000 m and a payload of less than 25 kg. The exception is a blend-body shape glider, which has a payload of approximately 800 kg and an operational depth around about 300 m. However, the commercialization of these gliders has been limited with only three know examples that have been successfully commercialized.

  7. Biomimetic membranes for sensor and separation applications

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus

    2009-01-01

    membrane-based sensor and/or separation devices? In the development of biomimetic sensor/separation technology, both channels (ion and water channels) and carriers (transporters) are important. Generally, each class of transport proteins conducts specific molecular species in and out of the cell while...... generally have a lower turnover but are capable of transport against gradients. For both classes of proteins, their unique flux-properties make them interesting as candidates in biomimetic sensor/separation devices. An ideal sensor/separation device requires the supporting biomimetic matrix to be virtually...... current developments of biomimetic sensor/separation devices....

  8. The Concept of Electroosmotically Driven Flow and Its Application to Biomimetics

    Institute of Scientific and Technical Information of China (English)

    Y. Y. Yan; J.B. Hull

    2004-01-01

    The concept of electroosmotically driven flow is built around understanding how the ionized particles or fluid are driven to flow by electroosmosis forces. Apart from the major applications of this concept to micro flow control elements which have been explored in parallel with the rapid developments in micro fabrication technologies, the present focus is on its application to biomimetics. As soil animals (in fact all living creatures) such as earthworms and dung beetles carry bioelectricity, the relative movement between the creatures and the surrounding soil which is a multi-component medium with moist content will generate electrophoresis or electroosmosis forces. Such forces drive the ionized moist content, normally water, to migrate from positive to negative poles under the action of electric double layer (EDL) effect, and effectively reduce the adhesion or drag. Predicting the electroosmotically driven flow in the vicinity of biological and animal surfaces is a key problem of drag/adhesion reduction and biomimetics design. The aim of this article is to demonstrate how the theory of electroosmotically driven flow has developed and to describe its broader significance for anti adhesion of soil animals and biomimetics design of soil machinery tools.

  9. Biological and Biomimetic Comb Polyelectrolytes

    Directory of Open Access Journals (Sweden)

    Aristeidis Papagiannopoulos

    2010-05-01

    Full Text Available Some new phenomena involved in the physical properties of comb polyelectrolyte solutions are reviewed. Special emphasis is given to synthetic biomimetic materials, and the structures formed by these molecules are compared with those of naturally occurring glycoprotein and proteoglycan solutions. Developments in the determination of the structure and dynamics (viscoelasticity of comb polymers in solution are also covered. Specifically the appearance of multi-globular structures, helical instabilities, liquid crystalline phases, and the self-assembly of the materials to produce hierarchical comb morphologies is examined. Comb polyelectrolytes are surface active and a short review is made of some recent experiments in this area that relate to their morphology when suspended in solution. We hope to emphasize the wide variety of phenomena demonstrated by the vast range of naturally occurring comb polyelectrolytes and the challenges presented to synthetic chemists designing biomimetic materials.

  10. BIOMIMETIC STRATEGIES IN ORGANIC SYNTHESIS. TERPENES

    Directory of Open Access Journals (Sweden)

    V. Kulcitki

    2012-12-01

    Full Text Available The current paper represents an outline of the selected contributions to the biomimetic procedures and approaches for the synthesis of terpenes with complex structure and diverse functionalisation pattern. These include homologation strategies, cyclisations, rearrangements, as well as biomimetic remote functionalisations.

  11. Underwater gas tornado

    International Nuclear Information System (INIS)

    We present the first experimental observation of a new hydrodynamic phenomenon, the underwater tornado. Simple measurements show that the tornado forms a vortex of the Rankine type, i.e. the rising gas rotates as a solid body and the liquid rotates with a velocity decreasing hyperbolically with the radius. We obtain the dependence of the tornado radius a on the gas stream value j theoretically: a ∼ j2/5. Processing of a set of experiments yielded the value 0.36 for the exponent in this expression. We also report the initial stages of the theoretical study of this phenomenon. (paper)

  12. Self-assembled Biodegradable Nanoparticles and Polysaccharides as Biomimetic ECM Nanostructures for the Synergistic effect of RGD and BMP-2 on Bone Formation.

    Science.gov (United States)

    Wang, Zhenming; Dong, Li; Han, Lu; Wang, Kefeng; Lu, Xiong; Fang, Liming; Qu, Shuxin; Chan, Chun Wai

    2016-01-01

    Producing biomimetic extracellular matrix (ECM) is an effective approach to improve biocompatibility of medical devices. In this study, biomimetic ECM nanostructures are constructed through layer-by-layer self-assembling positively charged chitosan (Chi), negatively charged oxidized sodium alginate (OAlg), and positively charged bovine serum albumin (BSA)-based nanoparticles. The BSA-based nanoparticles in the self-assembled films not only result in porous nanostructures similar to natural ECM, but also preserve the activity and realize the sustained release of Bone morphogenetic protein-2 (BMP-2). The results of bone marrow stem cells (BMSCs) culture demonstrate that the penta-peptide glycine-arginine-glycine-aspartate-serine (GRGDS) grafted Chi/OAlg films favor cell adhesion and proliferation. GRGDS and BMP-2 in biomimetic ECM nanostructures synergistically promote BMSC functions and new bone formation. The RGD and BMP incorporated biomimetic ECM coatings could be applied on a variety of biomedical devices to improve the bioactivity and biocompatibility. PMID:27121121

  13. Principles of goal-directed spatial robot navigation in biomimetic models.

    Science.gov (United States)

    Milford, Michael; Schulz, Ruth

    2014-11-01

    Mobile robots and animals alike must effectively navigate their environments in order to achieve their goals. For animals goal-directed navigation facilitates finding food, seeking shelter or migration; similarly robots perform goal-directed navigation to find a charging station, get out of the rain or guide a person to a destination. This similarity in tasks extends to the environment as well; increasingly, mobile robots are operating in the same underwater, ground and aerial environments that animals do. Yet despite these similarities, goal-directed navigation research in robotics and biology has proceeded largely in parallel, linked only by a small amount of interdisciplinary research spanning both areas. Most state-of-the-art robotic navigation systems employ a range of sensors, world representations and navigation algorithms that seem far removed from what we know of how animals navigate; their navigation systems are shaped by key principles of navigation in 'real-world' environments including dealing with uncertainty in sensing, landmark observation and world modelling. By contrast, biomimetic animal navigation models produce plausible animal navigation behaviour in a range of laboratory experimental navigation paradigms, typically without addressing many of these robotic navigation principles. In this paper, we attempt to link robotics and biology by reviewing the current state of the art in conventional and biomimetic goal-directed navigation models, focusing on the key principles of goal-oriented robotic navigation and the extent to which these principles have been adapted by biomimetic navigation models and why.

  14. High-performance mussel-inspired adhesives of reduced complexity

    Science.gov (United States)

    Ahn, B. Kollbe; Das, Saurabh; Linstadt, Roscoe; Kaufman, Yair; Martinez-Rodriguez, Nadine R.; Mirshafian, Razieh; Kesselman, Ellina; Talmon, Yeshayahu; Lipshutz, Bruce H.; Israelachvili, Jacob N.; Waite, J. Herbert

    2015-10-01

    Despite the recent progress in and demand for wet adhesives, practical underwater adhesion remains limited or non-existent for diverse applications. Translation of mussel-inspired wet adhesion typically entails catechol functionalization of polymers and/or polyelectrolytes, and solution processing of many complex components and steps that require optimization and stabilization. Here we reduced the complexity of a wet adhesive primer to synthetic low-molecular-weight catecholic zwitterionic surfactants that show very strong adhesion (~50 mJ m-2) and retain the ability to coacervate. This catecholic zwitterion adheres to diverse surfaces and self-assembles into a molecularly smooth, thin (<4 nm) and strong glue layer. The catecholic zwitterion holds particular promise as an adhesive for nanofabrication. This study significantly simplifies bio-inspired themes for wet adhesion by combining catechol with hydrophobic and electrostatic functional groups in a small molecule.

  15. Underwater Hearing in Turtles.

    Science.gov (United States)

    Willis, Katie L

    2016-01-01

    The hearing of turtles is poorly understood compared with the other reptiles. Although the mechanism of transduction of sound into a neural signal via hair cells has been described in detail, the rest of the auditory system is largely a black box. What is known is that turtles have higher hearing thresholds than other reptiles, with best frequencies around 500 Hz. They also have lower underwater hearing thresholds than those in air, owing to resonance of the middle ear cavity. Further studies demonstrated that all families of turtles and tortoises share a common middle ear cavity morphology, with scaling best suited to underwater hearing. This supports an aquatic origin of the group. Because turtles hear best under water, it is important to examine their vulnerability to anthropogenic noise. However, the lack of basic data makes such experiments difficult because only a few species of turtles have published audiograms. There are also almost no behavioral data available (understandable due to training difficulties). Finally, few studies show what kinds of sounds are behaviorally relevant. One notable paper revealed that the Australian snake-necked turtle (Chelodina oblonga) has a vocal repertoire in air, at the interface, and under water. Findings like these suggest that there is more to the turtle aquatic auditory scene than previously thought.

  16. Underwater running device

    International Nuclear Information System (INIS)

    An underwater running device for an underwater inspection device for detecting inner surfaces of a reactor or a water vessel has an outer frame and an inner frame, and both of them are connected slidably by an air cylinder and connected rotatably by a shaft. The outer frame has four outer frame legs, and each of the outer frame legs is equipped with a sucker at the top end. The inner frame has four inner frame legs each equipped with a sucker at the top end. The outer frame legs and the inner frame legs are each connected with the outer frame and the inner frame by the air cylinder. The outer and the inner frame legs can be elevated or lowered (or extended or contracted) by the air cylinder. The sucker is connected with a jet pump-type negative pressure generator. The device can run and move by repeating attraction and releasing of the outer frame legs and the inner frame legs alternately while maintaining the posture of the inspection device stably. (I.N.)

  17. Biomimetic surface modification of polyurethane with phospholipids grafted carbon nanotubes.

    Science.gov (United States)

    Tan, Dongsheng; Liu, Liuxu; Li, Zhen; Fu, Qiang

    2015-08-01

    To improve blood compatibility of polyurethane (PU), phospholipids grafted carbon nanotubes (CNTs) were prepared through zwitterion-mediated cycloaddition reaction and amide condensation, and then were added to the PU as fillers via solution mixing to form biomimetic surface. The properties of phospholipids grafted CNTs (CNT-PC) were investigated by thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and proton nuclear magnetic resonance ((1) H NMR). The results indicated that the phospholipids were grafted onto CNTs in high efficiency, and the hydrophilicity and dispersibility of the modified CNTs were improved effectively. The structures and properties of composites containing CNT-PC were investigated by optical microscope, XPS, and water contact angles. The results indicated that phospholipids were enriched on the surface with addition of 0.1 wt % of CNT-PC, which significantly reduced protein adsorption and platelet adhesion. The method of carrying phospholipids on the nanofiller to modify polymers has provided a promising way of constructing biomimetic phospholipid membrane on the surface to improve blood compatibility. PMID:25630300

  18. Preparation of biomimetic hydrophobic coatings on AZ91D magnesium alloy surface

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The hydrophobic coating has been a promising technology for improving surface performance. The surface performance of magnesium alloy has been limited in application. Furthermore, the hydrophobic of magnesium alloy is rarely investigated because magnesium alloy is an active metal alloy. In this paper, inspired by microstructure character of typical plant leaf surface such as lotus, the biomimetic hydrophobic coatings on AZ91D magnesium alloy surface were prepared by means of wet-chemical combining electroless. The samples were immersed into AgNO3 solution in wet-chemical method firstly. Then, biomimetic hydrophobic coatings were prepared by electroless after wet-method pretreatment. The microstructure was observed by SEM and the contact angles were measured by contact angle tester. The results indicated that the biomimetic hydrophobic coatings with uniform crystalline and dense structure could be obtained on AZ91D magnesium alloy surface. The results of contact angle revealed that the biomimetic nano-composite coatings were hydrophobic. The wet-chemical method treatment on the AZ91D magnesium alloy substrate provided a rough microstructure, thus improving adhesion of the coating and the substrate.

  19. Biomimetic microenvironments for regenerative endodontics.

    Science.gov (United States)

    Kaushik, Sagar N; Kim, Bogeun; Walma, Alexander M Cruz; Choi, Sung Chul; Wu, Hui; Mao, Jeremy J; Jun, Ho-Wook; Cheon, Kyounga

    2016-01-01

    Regenerative endodontics has been proposed to replace damaged and underdeveloped tooth structures with normal pulp-dentin tissue by providing a natural extracellular matrix (ECM) mimicking environment; stem cells, signaling molecules, and scaffolds. In addition, clinical success of the regenerative endodontic treatments can be evidenced by absence of signs and symptoms; no bony pathology, a disinfected pulp, and the maturation of root dentin in length and thickness. In spite of the various approaches of regenerative endodontics, there are several major challenges that remain to be improved: a) the endodontic root canal is a strong harbor of the endodontic bacterial biofilm and the fundamental etiologic factors of recurrent endodontic diseases, (b) tooth discolorations are caused by antibiotics and filling materials, (c) cervical root fractures are caused by endodontic medicaments, (d) pulp tissue is not vascularized nor innervated, and (e) the dentin matrix is not developed with adequate root thickness and length. Generally, current clinical protocols and recent studies have shown a limited success of the pulp-dentin tissue regeneration. Throughout the various approaches, the construction of biomimetic microenvironments of pulp-dentin tissue is a key concept of the tissue engineering based regenerative endodontics. The biomimetic microenvironments are composed of a synthetic nano-scaled polymeric fiber structure that mimics native pulp ECM and functions as a scaffold of the pulp-dentin tissue complex. They will provide a framework of the pulp ECM, can deliver selective bioactive molecules, and may recruit pluripotent stem cells from the vicinity of the pulp apex. The polymeric nanofibers are produced by methods of self-assembly, electrospinning, and phase separation. In order to be applied to biomedical use, the polymeric nanofibers require biocompatibility, stability, and biodegradability. Therefore, this review focuses on the development and application of the

  20. Biomimetic microenvironments for regenerative endodontics.

    Science.gov (United States)

    Kaushik, Sagar N; Kim, Bogeun; Walma, Alexander M Cruz; Choi, Sung Chul; Wu, Hui; Mao, Jeremy J; Jun, Ho-Wook; Cheon, Kyounga

    2016-01-01

    Regenerative endodontics has been proposed to replace damaged and underdeveloped tooth structures with normal pulp-dentin tissue by providing a natural extracellular matrix (ECM) mimicking environment; stem cells, signaling molecules, and scaffolds. In addition, clinical success of the regenerative endodontic treatments can be evidenced by absence of signs and symptoms; no bony pathology, a disinfected pulp, and the maturation of root dentin in length and thickness. In spite of the various approaches of regenerative endodontics, there are several major challenges that remain to be improved: a) the endodontic root canal is a strong harbor of the endodontic bacterial biofilm and the fundamental etiologic factors of recurrent endodontic diseases, (b) tooth discolorations are caused by antibiotics and filling materials, (c) cervical root fractures are caused by endodontic medicaments, (d) pulp tissue is not vascularized nor innervated, and (e) the dentin matrix is not developed with adequate root thickness and length. Generally, current clinical protocols and recent studies have shown a limited success of the pulp-dentin tissue regeneration. Throughout the various approaches, the construction of biomimetic microenvironments of pulp-dentin tissue is a key concept of the tissue engineering based regenerative endodontics. The biomimetic microenvironments are composed of a synthetic nano-scaled polymeric fiber structure that mimics native pulp ECM and functions as a scaffold of the pulp-dentin tissue complex. They will provide a framework of the pulp ECM, can deliver selective bioactive molecules, and may recruit pluripotent stem cells from the vicinity of the pulp apex. The polymeric nanofibers are produced by methods of self-assembly, electrospinning, and phase separation. In order to be applied to biomedical use, the polymeric nanofibers require biocompatibility, stability, and biodegradability. Therefore, this review focuses on the development and application of the

  1. OFDM for underwater acoustic communications

    CERN Document Server

    Zhou, Shengli

    2014-01-01

    A blend of introductory material and advanced signal processing and communication techniques, of critical importance to underwater system and network development This book, which is the first to describe the processing techniques central to underwater OFDM, is arranged into four distinct sections: First, it describes the characteristics of underwater acoustic channels, and stresses the difference from wireless radio channels. Then it goes over the basics of OFDM and channel coding. The second part starts with an overview of the OFDM receiver, and develops various modules for the receiver des

  2. Progress of Biomimetic Flapping Foil UUV Research and Its Key Technology%仿生扑翼UUV的研究进展及关键技术

    Institute of Scientific and Technical Information of China (English)

    宋保维; 丁浩; 黄桥高; 吴文辉; 朱崎峰

    2011-01-01

    针对当前无人水下航行器低速下近目标作业能力较差的问题,人们开始了对仿生扑翼推进方式的探索研究,仿生扑翼UUV应运而生.简要介绍了仿生扑翼UUV的概念、特点及其应用,综述了仿生扑翼UUV的国内外研究成果及现状.在此基础上对仿生扑翼UUV的研制所面临的一些关键技术进行了讨论,并结合目前的研究情况,展望了仿生扑翼UUV的未来发展趋势.%Biomimetic flapping foil UUV (Unmanned Underwater Vehicle) turns out at the study of the biomimetic flapping foil motion method for improving UUV's capacity on the near-object. The concept, characteristics and application of biomimetic flapping foil UUV are briefly introduced. The domestic and overseas research production and situation of biomimetie flapping foil UUV are summarized.According to these, several key technologies of biomimetic flapping foil UUV are discussed. Taking into account the present situation,the future on the research of biomimetic flapping foil UUV is forecasted.

  3. The preosteoblast response of electrospinning PLGA/PCL nanofibers: effects of biomimetic architecture and collagen I

    Directory of Open Access Journals (Sweden)

    Qian YZ

    2016-08-01

    Full Text Available Yunzhu Qian,1,2 Hanbang Chen,1 Yang Xu,1 Jianxin Yang,2 Xuefeng Zhou,3 Feimin Zhang,1 Ning Gu3 1Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, 2Center of Stomatology, The Second Affiliated Hospital of Soochow University, Suzhou, 3School of Biological Science and Medical Engineering, Southeast University, Nanjing, People’s Republic of China Abstract: Constructing biomimetic structure and incorporating bioactive molecules is an effective strategy to achieve a more favorable cell response. To explore the effect of electrospinning (ES nanofibrous architecture and collagen I (COL I-incorporated modification on tuning osteoblast response, a resorbable membrane composed of poly(lactic-co-glycolic acid/poly(caprolactone (PLGA/PCL; 7:3 w/w was developed via ES. COL I was blended into PLGA/PCL solution to prepare composite ES membrane. Notably, relatively better cell response was delivered by the bioactive ES-based membrane which was fabricated by modification of 3,4-dihydroxyphenylalanine and COL I. After investigation by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurement, and mechanical test, polyporous three-dimensional nanofibrous structure with low tensile force and the successful integration of COL I was obtained by the ES method. Compared with traditional PLGA/PCL membrane, the surface hydrophilicity of collagen-incorporated membranes was largely enhanced. The behavior of mouse preosteoblast MC3T3-E1 cell infiltration and proliferation on membranes was studied at 24 and 48 hours. The negative control was fabricated by solvent casting. Evaluation of cell adhesion and morphology demonstrated that all the ES membranes were more favorable for promoting the cell adhesion and spreading than the casting membrane. Cell Counting Kit-8 assays revealed that biomimetic architecture, surface topography, and bioactive properties of membranes were favorable for cell

  4. Biomimetic, Catalytic Oxidation in Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Shun-lchi Murahashi

    2005-01-01

    @@ 1Introduction Oxidation is one of the most fundamental reactions in organic synthesis. Owing to the current need to develop forward-looking technology that is environmentally acceptable with respect many aspects. The most attractive approaches are biomimetic oxidation reactions that are closely related to the metabolism of living things. The metabolisms are governed by a variety of enzymes such as cytochrome P-450 and flavoenzyme.Simulation of the function of these enzymes with simple transition metal complex catalyst or organic catalysts led to the discovery of biomimetic, catalytic oxidations with peroxides[1]. We extended such biomimetic methods to the oxidation with molecular oxygen under mild conditions.

  5. Challenges in Commercializing Biomimetic Membranes

    Directory of Open Access Journals (Sweden)

    Mark Perry

    2015-11-01

    Full Text Available The discovery of selective water channel proteins—aquaporins—has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One category includes customer-related barriers, which can be influenced to some extent. Another category includes market-technical-related barriers, which can be very difficult to overcome by an organization/company aiming at successfully introducing their innovation on the market—in particular if both the organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments relevant for biomimetic aquaporin membranes.

  6. Safety aspects for underwater vehicles

    Digital Repository Service at National Institute of Oceanography (India)

    Madhan, R.; Navelkar, G.S.; Desa, E.S.; Afzulpurkar, S.; Prabhudesai, S.P.; Dabholkar, N.; Mascarenhas, A.A.M.Q.; Maurya, P.

    . This stresses for implementation of multiple safety measures of a high degree so that the platform operates continuously in a fail-safe mode. This paper discusses issues on safety measures implemented on the autonomous underwater platforms namely MAYA AUV...

  7. Design of Autonomous Underwater Vehicle

    OpenAIRE

    Tadahiro Hyakudome

    2011-01-01

    There are concerns about the impact that global warming will have on our environment, and which will inevitably result in expanding deserts and rising water levels. While a lot of underwater vehicles are utilized, AUVs (Autonomous Underwater Vehicle) were considered and chosen, as the most suitable tool for conduction survey concerning these global environmental problems. AUVs can comprehensive survey because the vehicle does not have to be connected to the support vessel by tether cable. Whe...

  8. Nacre-inspired design of mechanical stable coating with underwater superoleophobicity.

    Science.gov (United States)

    Xu, Li-Ping; Peng, Jitao; Liu, Yibiao; Wen, Yongqiang; Zhang, Xueji; Jiang, Lei; Wang, Shutao

    2013-06-25

    Because of the frequent oil spill accidents in marine environment, stable superoleophobic coatings under seawater are highly desired. Current underwater superoleophobic surfaces often suffer from mechanical damages and lose their superoleophobicity gradually. It remains a challenge to fabricate a stable and robust underwater superoleophobic film which can endure harsh conditions in practical application. Nacre is one of most extensively studied rigid biological materials. Inspired by the outstanding mechanical property of seashell nacre and those underwater superoleophobic surfaces from nature, we fabricated a polyelectrolyte/clay hybrid film via typical layer-by-layer (LBL) method based on building blocks with high surface energy. 'Bricks-and-mortar' structure of seashell nacre was conceptually replicated into the prepared film, which endows the obtained film with excellent mechanical property and great abrasion resistance. In addtion, the prepared film also exhibits stable underwater superoleophobicity, low oil adhesion, and outstanding environment durability in artificial seawater. We anticipate that this work will provide a new method to design underwater low-oil-adhesion film with excellent mechanical property and improved stability, which may advance the practical applications in marine antifouling and microfluidic devices.

  9. Underwater optical wireless communication network

    Science.gov (United States)

    Arnon, Shlomi

    2010-01-01

    The growing need for underwater observation and subsea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, biogeochemical, evolutionary, and ecological changes in the sea, ocean, and lake environments, and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. Models are presented for three kinds of optical wireless communication links: (a) a line-of-sight link, (b) a modulating retroreflector link, and (c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered light it was possible to mitigate this decrease in some cases. It is concluded from the analysis that a high-data-rate underwater optical wireless network is a feasible solution for emerging applications such as UUV-to-UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.

  10. Biomimetics Bioinspired Hierarchical-Structured Surfaces for Green Science and Technology

    CERN Document Server

    Bhushan, Bharat

    2012-01-01

    This book presents an overview of the general field of biomimetics - lessons from nature. It presents various examples of biomimetics, including roughness-induced superomniphobic surfaces which provide functionality of commercial interest. The major focus in the book is on lotus effect, rose petal effect, shark skin effect, and gecko adhesion.  For each example, the book first presents characterization of an object to understand how a natural object provides functionality, followed by modeling and then fabrication of structures in the lab using nature’s route to verify one’s understanding of nature and provide guidance for development of optimum structures. Once it is understood how nature does it, examples of fabrication of optimum structures using smart materials and fabrication techniques, are presented. Examples of nature inspired objects are also presented throughout.

  11. Biomimetic cardiovascular stents for in vivo re-endothelialization.

    Science.gov (United States)

    Liang, Chunyong; Hu, Yuecheng; Wang, Hongshui; Xia, Dan; Li, Qiang; Zhang, Jiao; Yang, Jianjun; Li, Baoe; Li, Haipeng; Han, Dong; Dong, Mingdong

    2016-10-01

    The use of cardiovascular stents for rapid in vivo re-endothelialization is a promising strategy for reducing cardiovascular implantation or preventing local thrombus formation and restenosis. Surface-patterned intravascular endoprosthetic stents have been developed to prevent life-threatening complications. In this study, vascular smooth muscle cell (VSMC)-biomimetic surface patterns were fabricated on 316L cardiovascular stents using a femtosecond laser and then implanted into the iliac artery of rabbit. The in vitro data revealed that the bionic surface patterns matched the morphology of the VSMCs well, which promotes the adhesion, proliferation, and migration of human umbilical vein endothelial cells. In addition, the patterned surfaces can significantly enhance re-endothelialization. Consequently, the surface biomimetic stent with the VSMC surface pattern is likely an effective approach to ensure rapid re-endothelialization and possibly reduce the incidence of in-stent restenosis. PMID:27380443

  12. Accelerating the design of biomimetic materials by integrating RNA-seq with proteomics and materials science.

    Science.gov (United States)

    Guerette, Paul A; Hoon, Shawn; Seow, Yiqi; Raida, Manfred; Masic, Admir; Wong, Fong T; Ho, Vincent H B; Kong, Kiat Whye; Demirel, Melik C; Pena-Francesch, Abdon; Amini, Shahrouz; Tay, Gavin Z; Ding, Dawei; Miserez, Ali

    2013-10-01

    Efforts to engineer new materials inspired by biological structures are hampered by the lack of genomic data from many model organisms studied in biomimetic research. Here we show that biomimetic engineering can be accelerated by integrating high-throughput RNA-seq with proteomics and advanced materials characterization. This approach can be applied to a broad range of systems, as we illustrate by investigating diverse high-performance biological materials involved in embryo protection, adhesion and predation. In one example, we rapidly engineer recombinant squid sucker ring teeth proteins into a range of structural and functional materials, including nanopatterned surfaces and photo-cross-linked films that exceed the mechanical properties of most natural and synthetic polymers. Integrating RNA-seq with proteomics and materials science facilitates the molecular characterization of natural materials and the effective translation of their molecular designs into a wide range of bio-inspired materials.

  13. Biomimetic autonomous robot inspired by the Cyanea capillata (Cyro)

    International Nuclear Information System (INIS)

    A biomimetic robot inspired by Cyanea capillata, termed as ‘Cyro’, was developed to meet the functional demands of underwater surveillance in defense and civilian applications. The vehicle was designed to mimic the morphology and swimming mechanism of the natural counterpart. The body of the vehicle consists of a rigid support structure with linear DC motors which actuate eight mechanical arms. The mechanical arms in conjunction with artificial mesoglea create the hydrodynamic force required for propulsion. The full vehicle measures 170 cm in diameter and has a total mass of 76 kg. An analytical model of the mechanical arm kinematics was developed. The analytical and experimental bell kinematics were analyzed and compared to the C. capillata. Cyro was found to reach the water surface untethered and autonomously from a depth of 182 cm in five actuation cycles. It achieved an average velocity of 8.47 cm s−1 while consuming an average power of 70 W. A two-axis thrust stand was developed to calculate the thrust directly from a single bell segment yielding an average thrust of 27.9 N for the whole vehicle. Steady state velocity during Cyro's swimming test was not reached but the measured performance during its last swim cycle resulted in a cost of transport of 10.9 J (kg ⋅ m)−1 and total efficiency of 0.03. (paper)

  14. Optimization of a tensegrity wing for biomimetic applications

    Science.gov (United States)

    Moored, Keith W., III; Taylor, Stuart A.; Bart-Smith, Hilary

    2006-03-01

    Current attempts to build fast, efficient, and maneuverable underwater vehicles have looked to nature for inspiration. However, they have all been based on traditional propulsive techniques, i.e. rotary motors. In the current study a promising and potentially revolutionary approach is taken that overcomes the limitations of these traditional methods-morphing structure concepts with integrated actuation and sensing. Inspiration for this work comes from the manta ray (Manta birostris) and other batoid fish. These creatures are highly maneuverable but are also able to cruise at high speeds over long distances. In this paper, the structural foundation for the biomimetic morphing wing is a tensegrity structure. A preliminary procedure is presented for developing morphing tensegrity structures that include actuating elements. A shape optimization method is used that determines actuator placement and actuation amount necessary to achieve the measured biological displacement field of a ray. Lastly, an experimental manta ray wing is presented that measures the static and dynamic pressure field acting on the ray's wings during a normal flapping cycle.

  15. Biomimetic autonomous robot inspired by the Cyanea capillata (Cyro).

    Science.gov (United States)

    Villanueva, Alex A; Marut, Kenneth J; Michael, Tyler; Priya, Shashank

    2013-12-01

    A biomimetic robot inspired by Cyanea capillata, termed as 'Cyro', was developed to meet the functional demands of underwater surveillance in defense and civilian applications. The vehicle was designed to mimic the morphology and swimming mechanism of the natural counterpart. The body of the vehicle consists of a rigid support structure with linear DC motors which actuate eight mechanical arms. The mechanical arms in conjunction with artificial mesoglea create the hydrodynamic force required for propulsion. The full vehicle measures 170 cm in diameter and has a total mass of 76 kg. An analytical model of the mechanical arm kinematics was developed. The analytical and experimental bell kinematics were analyzed and compared to the C. capillata. Cyro was found to reach the water surface untethered and autonomously from a depth of 182 cm in five actuation cycles. It achieved an average velocity of 8.47 cm s(-1) while consuming an average power of 70 W. A two-axis thrust stand was developed to calculate the thrust directly from a single bell segment yielding an average thrust of 27.9 N for the whole vehicle. Steady state velocity during Cyro's swimming test was not reached but the measured performance during its last swim cycle resulted in a cost of transport of 10.9 J (kg ⋅ m)(-1) and total efficiency of 0.03. PMID:24166747

  16. Molecular motor assembly of a biomimetic system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.

  17. Biomimetic catalysis: Taking on the turnover challenge

    Science.gov (United States)

    Hooley, Richard J.

    2016-03-01

    Emulating the efficiency with which enzymes catalyse reactions has often been used as inspiration to develop self-assembled cages. Now two studies present approaches to achieving catalyst turnover -- one of the biggest challenges in achieving truly biomimetic catalysis.

  18. Biomimetic membranes for sensor and separation applications

    CERN Document Server

    2012-01-01

    This book addresses the possibilities and challenges in mimicking biological membranes and creating membrane-based sensor and separation devices. It covers recent advances in developing biomimetic membranes for technological applications with a focus on the use of integral membrane protein mediated transport. It describes the fundamentals of biosensing as well as separation and shows how the two processes work together in biological systems. The book provides an overview of the current state of the art, points to areas that need further investigation and anticipates future directions in the field. Biomimetics is a truly cross-disciplinary approach and this is exemplified by the challenges in mimicking osmotic processes as they occur in nature using aquaporin protein water channels as central building blocks. In the development of a biomimetic sensor/separation technology, both channel and carrier proteins are important and examples of how these may be reconstituted and controlled in biomimetic membranes are ...

  19. Biomimetic Active Touch with Fingertips and Whiskers.

    Science.gov (United States)

    Lepora, Nathan F

    2016-01-01

    This study provides a synthetic viewpoint that compares, contrasts, and draws commonalities for biomimetic perception over a range of tactile sensors and tactile stimuli. Biomimetic active perception is formulated from three principles: (i) evidence accumulation based on leading models of perceptual decision making; (ii) action selection with an evidence-based policy, here based on overt focal attention; and (iii) sensory encoding of evidence based on neural coding. Two experiments with each of three biomimetic tactile sensors are considered: the iCub (capacitive) fingertip, the TacTip (optical) tactile sensor, and BIOTACT whiskers. For each sensor, one experiment considers a similar task (perception of shape and location) and the other a different tactile perception task. In all experiments, active perception with a biomimetic action selection policy based on focal attention outperforms passive perception with static or random action selection. The active perception also consistently reaches superresolved accuracy (hyperacuity) finer than the spacing between tactile elements. Biomimetic active touch thus offers a common approach for biomimetic tactile sensors to accurately and robustly characterize and explore non-trivial, uncertain environments analogous to how animals perceive the natural world. PMID:27168603

  20. Biomimetic mechanism for micro aircraft

    Science.gov (United States)

    Pines, Darryll J. (Inventor); Bohorquez, Felipe A. (Inventor); Sirohi, Jayant (Inventor)

    2005-01-01

    A biomimetic pitching and flapping mechanism including a support member, at least two blade joints for holding blades and operatively connected to the support member. An outer shaft member is concentric with the support member, and an inner shaft member is concentric with the outer shaft member. The mechanism allows the blades of a small-scale rotor to be actuated in the flap and pitch degrees of freedom. The pitching and the flapping are completely independent from and uncoupled to each other. As such, the rotor can independently flap, or independently pitch, or flap and pitch simultaneously with different amplitudes and/or frequencies. The mechanism can also be used in a non-rotary wing configuration, such as an ornithopter, in which case the rotational degree of freedom would be suppressed.

  1. Challenges in commercializing biomimetic membranes

    DEFF Research Database (Denmark)

    Perry, Mark; Madsen, Steen Ulrik; Jørgensen, Tine Elkjær;

    2015-01-01

    The discovery of selective water channel proteins—aquaporins—has prompted growing interest in using these proteins, as the building blocks for designing new types of membranes. However, as with any other new and potentially disruptive technology, barriers for successful market entry exist. One...... barriers and challenges associated with introducing biomimetic aquaporin membranes. These include technical issues in membrane production and product testing. Then we discuss possible business models for introducing new technologies in general, followed by a presentation of beach-head market segments...... organization and the technology are at early stages. Often, one faces barriers from both these categories at the same time, which makes it necessary to gain insight of the particular market when introducing a new innovative product. In this review we present the basic concepts and discuss some of these...

  2. Biomimetic use of genetic algorithms

    CERN Document Server

    Dessalles, Jean-Louis

    2011-01-01

    Genetic algorithms are considered as an original way to solve problems, probably because of their generality and of their "blind" nature. But GAs are also unusual since the features of many implementations (among all that could be thought of) are principally led by the biological metaphor, while efficiency measurements intervene only afterwards. We propose here to examine the relevance of these biomimetic aspects, by pointing out some fundamental similarities and divergences between GAs and the genome of living beings shaped by natural selection. One of the main differences comes from the fact that GAs rely principally on the so-called implicit parallelism, while giving to the mutation/selection mechanism the second role. Such differences could suggest new ways of employing GAs on complex problems, using complex codings and starting from nearly homogeneous populations.

  3. Fundamental Difficulties Associated With Underwater Wet Welding

    OpenAIRE

    Joshua E. Omajene,; Jukka Martikainen

    2014-01-01

    The offshore industries carry out welding activities in the wet environment. It is evident that the wet environments possess difficulties in carrying out underwater welding. Therefore there is the need to improve the quality of weld achieved in underwater welding. This paper investigates the difficulties associated with underwater welding. The objective of this research paper is to identify and analyze the different difficulties in underwater welding so as to make a clear back...

  4. Energy source possibilities in underwater technics

    Science.gov (United States)

    Farin, Juho

    1991-04-01

    Underwater energy source possibilities are treated. The power demand of underwater vehicles is restricted to approximately 0.5 MW. Besides well known primary and secondary batteries as well as conventional diesel engines and closed cycle diesels, fuel cells, radio nuclear isotopes and small nuclear reactors have already been installed or tested in conditions representative of underwater.

  5. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters......, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...

  6. Design of Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Tadahiro Hyakudome

    2011-03-01

    Full Text Available There are concerns about the impact that global warming will have on our environment, and which will inevitably result in expanding deserts and rising water levels. While a lot of underwater vehicles are utilized, AUVs (Autonomous Underwater Vehicle were considered and chosen, as the most suitable tool for conduction survey concerning these global environmental problems. AUVs can comprehensive survey because the vehicle does not have to be connected to the support vessel by tether cable. When such underwater vehicles are made, it is necessary to consider about the following things. 1 Seawater and Water Pressure Environment, 2 Sink, 3 There are no Gas or Battery Charge Stations, 4 Global Positioning System cannot use, 5 Radio waves cannot use. In the paper, outline of above and how deal about it are explained.

  7. Underwater laser imaging system (UWLIS)

    Energy Technology Data Exchange (ETDEWEB)

    DeLong, M. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    Practical limitations with underwater imaging systems area reached when the noise in the back scattered radiation generated in the water between the imaging system and the target obscures the spatial contrast and resolution necessary for target discovery and identification. The advent of high power lasers operating in the blue-green portion of the visible spectrum (oceanic transmission window) has led to improved experimental illumination systems for underwater imaging. Range-gated and synchronously scanned devices take advantage of the unique temporal and spatial coherence properties of laser radiation, respectively, to overcome the deleterious effects of common volume back scatter.

  8. OFDM for Underwater Acoustic Communication

    OpenAIRE

    Thottappilly, Arjun

    2011-01-01

    Communicating wirelessly underwater has been an area of interest for researchers, engineers, and practitioners alike. One of the main reasons for the slow rate of progress in this area is that the underwater acoustic channel is in general much more hostile â in terms of multipath, frequency selectivity, noise, and the Doppler effect â than the over-the-air radio frequency channel. In this work a time warp based technique which can be used to model time-varying wideband Doppler shifts (as ...

  9. Mussel adhesion-employed water-immiscible fluid bioadhesive for urinary fistula sealing.

    Science.gov (United States)

    Kim, Hyo Jeong; Hwang, Byeong Hee; Lim, Seonghye; Choi, Bong-Hyuk; Kang, Seok Ho; Cha, Hyung Joon

    2015-12-01

    Urinary fistulas, abnormal openings of a urinary tract organ, are serious complications and conventional management strategies are not satisfactory. For more effective and non-invasive fistula repair, fluid tissue adhesives or sealants have been suggested. However, conventional products do not provide a suitable solution due to safety problems and poor underwater adhesion under physiological conditions. Herein, we proposed a unique water-immiscible mussel protein-based bioadhesive (WIMBA) exhibiting strong underwater adhesion which was employed by two adhesion strategies of marine organisms; 3,4-dihydroxy-l-phenylalanine (DOPA)-mediated strong adhesion and water-immiscible coacervation. The developed biocompatible WIMBA successfully sealed ex vivo urinary fistulas and provided good durability and high compliance. Thus, WIMBA could be used as a promising sealant for urinary fistula management with further expansion to diverse internal body applications. PMID:26352517

  10. The preosteoblast response of electrospinning PLGA/PCL nanofibers: effects of biomimetic architecture and collagen I.

    Science.gov (United States)

    Qian, Yunzhu; Chen, Hanbang; Xu, Yang; Yang, Jianxin; Zhou, Xuefeng; Zhang, Feimin; Gu, Ning

    2016-01-01

    Constructing biomimetic structure and incorporating bioactive molecules is an effective strategy to achieve a more favorable cell response. To explore the effect of electrospinning (ES) nanofibrous architecture and collagen I (COL I)-incorporated modification on tuning osteoblast response, a resorbable membrane composed of poly(lactic-co-glycolic acid)/poly(caprolactone) (PLGA/PCL; 7:3 w/w) was developed via ES. COL I was blended into PLGA/PCL solution to prepare composite ES membrane. Notably, relatively better cell response was delivered by the bioactive ES-based membrane which was fabricated by modification of 3,4-dihydroxyphenylalanine and COL I. After investigation by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurement, and mechanical test, polyporous three-dimensional nanofibrous structure with low tensile force and the successful integration of COL I was obtained by the ES method. Compared with traditional PLGA/PCL membrane, the surface hydrophilicity of collagen-incorporated membranes was largely enhanced. The behavior of mouse preosteoblast MC3T3-E1 cell infiltration and proliferation on membranes was studied at 24 and 48 hours. The negative control was fabricated by solvent casting. Evaluation of cell adhesion and morphology demonstrated that all the ES membranes were more favorable for promoting the cell adhesion and spreading than the casting membrane. Cell Counting Kit-8 assays revealed that biomimetic architecture, surface topography, and bioactive properties of membranes were favorable for cell growth. Analysis of β1 integrin expression level by immunofluorescence indicated that such biomimetic architecture, especially COL I-grafted surface, plays a key role in cell adhesion and proliferation. The real-time polymerase chain reaction suggested that both surface topography and bioactive properties could facilitate the cell adhesion. The combined effect of biomimetic architecture with enhanced

  11. The preosteoblast response of electrospinning PLGA/PCL nanofibers: effects of biomimetic architecture and collagen I

    Science.gov (United States)

    Qian, Yunzhu; Chen, Hanbang; Xu, Yang; Yang, Jianxin; Zhou, Xuefeng; Zhang, Feimin; Gu, Ning

    2016-01-01

    Constructing biomimetic structure and incorporating bioactive molecules is an effective strategy to achieve a more favorable cell response. To explore the effect of electrospinning (ES) nanofibrous architecture and collagen I (COL I)-incorporated modification on tuning osteoblast response, a resorbable membrane composed of poly(lactic-co-glycolic acid)/poly(caprolactone) (PLGA/PCL; 7:3 w/w) was developed via ES. COL I was blended into PLGA/PCL solution to prepare composite ES membrane. Notably, relatively better cell response was delivered by the bioactive ES-based membrane which was fabricated by modification of 3,4-dihydroxyphenylalanine and COL I. After investigation by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurement, and mechanical test, polyporous three-dimensional nanofibrous structure with low tensile force and the successful integration of COL I was obtained by the ES method. Compared with traditional PLGA/PCL membrane, the surface hydrophilicity of collagen-incorporated membranes was largely enhanced. The behavior of mouse preosteoblast MC3T3-E1 cell infiltration and proliferation on membranes was studied at 24 and 48 hours. The negative control was fabricated by solvent casting. Evaluation of cell adhesion and morphology demonstrated that all the ES membranes were more favorable for promoting the cell adhesion and spreading than the casting membrane. Cell Counting Kit-8 assays revealed that biomimetic architecture, surface topography, and bioactive properties of membranes were favorable for cell growth. Analysis of β1 integrin expression level by immunofluorescence indicated that such biomimetic architecture, especially COL I-grafted surface, plays a key role in cell adhesion and proliferation. The real-time polymerase chain reaction suggested that both surface topography and bioactive properties could facilitate the cell adhesion. The combined effect of biomimetic architecture with enhanced

  12. Underwater locomotion strategy by a benthic pennate diatom Navicula sp.

    Science.gov (United States)

    Wang, Jiadao; Cao, Shan; Du, Chuan; Chen, Darong

    2013-10-01

    The mechanism of diatom locomotion has been widely researched but still remains a hypothesis. There are several questionable points on the prevailing model proposed by Edgar, and some of the observed phenomena cannot be completely explained by this model. In this paper, we undertook detailed investigations of cell structures, locomotion, secreted mucilage, and bending deformation for a benthic pennate diatom Navicula species. According to these broad evidences, an updated locomotion model is proposed. For Navicula sp., locomotion is realized via two or more pseudopods or stalks protruded out of the frustules. The adhesion can be produced due to the pull-off of one pseudopod or stalk from the substratum through extracellular polymeric substances. And the positive pressure is generated to balance the adhesion because of the push-down of another pseudopod or stalk onto the substratum. Because of the positive pressure, friction is generated, acting as a driving force of locomotion, and the other pseudopod or stalk can detach from the substratum, resulting in the locomotion. Furthermore, this model is validated by the force evaluation and can better explain observed phenomena. This updated model would provide a novel aspect on underwater locomotion strategy, hence can be useful in terms of artificial underwater locomotion devices.

  13. An Underwater Color Image Quality Evaluation Metric.

    Science.gov (United States)

    Yang, Miao; Sowmya, Arcot

    2015-12-01

    Quality evaluation of underwater images is a key goal of underwater video image retrieval and intelligent processing. To date, no metric has been proposed for underwater color image quality evaluation (UCIQE). The special absorption and scattering characteristics of the water medium do not allow direct application of natural color image quality metrics especially to different underwater environments. In this paper, subjective testing for underwater image quality has been organized. The statistical distribution of the underwater image pixels in the CIELab color space related to subjective evaluation indicates the sharpness and colorful factors correlate well with subjective image quality perception. Based on these, a new UCIQE metric, which is a linear combination of chroma, saturation, and contrast, is proposed to quantify the non-uniform color cast, blurring, and low-contrast that characterize underwater engineering and monitoring images. Experiments are conducted to illustrate the performance of the proposed UCIQE metric and its capability to measure the underwater image enhancement results. They show that the proposed metric has comparable performance to the leading natural color image quality metrics and the underwater grayscale image quality metrics available in the literature, and can predict with higher accuracy the relative amount of degradation with similar image content in underwater environments. Importantly, UCIQE is a simple and fast solution for real-time underwater video processing. The effectiveness of the presented measure is also demonstrated by subjective evaluation. The results show better correlation between the UCIQE and the subjective mean opinion score. PMID:26513783

  14. Underwater Robots Surface in Utah

    Science.gov (United States)

    Hurd, Randy C.; Hacking, Kip S.; Damarjian, Jennifer L.; Wright, Geoffrey A.; Truscott, Tadd

    2015-01-01

    Underwater robots (or ROVs: Remotely Operated Vehicles as they are typically called in industry) have recently become a very popular instructional STEM activity. Nationally, ROVs have been used in science and technology classrooms for several years in cities such as Seattle, San Diego, Virginia Beach, and other coastal areas. In the past two…

  15. Calibration of Underwater Sound Transducers

    Directory of Open Access Journals (Sweden)

    H.R.S. Sastry

    1983-07-01

    Full Text Available The techniques of calibration of underwater sound transducers for farfield, near-field and closed environment conditions are reviewed in this paper .The design of acoustic calibration tank is mentioned. The facilities available at Naval Physical & Oceanographic Laboratory, Cochin for calibration of transducers are also listed.

  16. Underwater Applications of Acoustical Holography

    Directory of Open Access Journals (Sweden)

    P. C. Mehta

    1984-01-01

    Full Text Available The paper describes the basic technique of acoustical holography. Requirements for recording the acoustical hologram are discussed with its ability for underwater imaging in view. Some practical systems for short-range and medium-range imaging are described. The advantages of acoustical holography over optical imaging, acoustical imaging and sonars are outlined.

  17. Underwater noise due to precipitation

    DEFF Research Database (Denmark)

    Crum, Lawrence A.; Pumphrey, Hugh C.; Prosperetti, Andrea;

    1989-01-01

    In 1959, G. Franz published a thorough investigation of the underwater sound produced by liquid drop impacts [G. Franz, J. Acoust. Soc. Am. 31, 1080 (1959)]. He discovered that, under certain conditions, a gas bubble was entrained by the impacting droplet, and the subsequent oscillation of this b......In 1959, G. Franz published a thorough investigation of the underwater sound produced by liquid drop impacts [G. Franz, J. Acoust. Soc. Am. 31, 1080 (1959)]. He discovered that, under certain conditions, a gas bubble was entrained by the impacting droplet, and the subsequent oscillation...... of this bubble resulted in a large amount of radiated sound. Recently, Scrimger has measured the underwater sound produced by rainfall and has discovered that a well-defined spectral peak exists near 15 kHz [J. A. Scrimger, Nature 318, 647 (1985)]. The sound produced by the impact of water droplets on a water...... surface, both for individual and for multiple events such as those produced by artificial and natural rainfall, has been examined. The studies indicate that the major contribution to the underwater noise produced by both rain and snow is that associated with the oscillations of gas bubbles introduced...

  18. Shape optimisation of an underwater Bernoulli gripper

    Science.gov (United States)

    Flint, Tim; Sellier, Mathieu

    2015-11-01

    In this work, we are interested in maximising the suction produced by an underwater Bernoulli gripper. Bernoulli grippers work by exploiting low pressure regions caused by the acceleration of a working fluid through a narrow channel, between the gripper and a surface, to provide a suction force. This mechanism allows for non-contact adhesion to various surfaces and may be used to hold a robot to the hull of a ship while it inspects welds for example. A Bernoulli type pressure analysis was used to model the system with a Darcy friction factor approximation to include the effects of frictional losses. The analysis involved a constrained optimisation in order to avoid cavitation within the mechanism which would result in decreased performance and damage to surfaces. A sensitivity based method and gradient descent approach was used to find the optimum shape of a discretised surface. The model's accuracy has been quantified against finite volume computational fluid dynamics simulation (ANSYS CFX) using the k- ω SST turbulence model. Preliminary results indicate significant improvement in suction force when compared to a simple geometry by retaining a pressure just above that at which cavitation would occur over as much surface area as possible. Doctoral candidate in the Mechanical Engineering Department of the University of Canterbury, New Zealand.

  19. Challenges in biomimetic design and innovation

    DEFF Research Database (Denmark)

    Lenau, Torben Anker; Barfoed, Michael; Shu, Li

    Biomimetic design copies desired principles found in nature and implement them into artificial applications. Applications could be products we use in our daily life but it can also be used to inspire material innovation. However there are significant challenges in performing biomimetic design. One....... This is a key issue in design and innovation work where problem identification and systematic search for suitable solution principle are major activities. One way to deal with this challenge is to use a biology search method. The use of such a method is illustrated with a case story describing the design...... including the terminology and knowledge organisation. It is often easy to recognise the splendour of a biological solution, but it can be much more difficult to understand the underlying mechanisms. Another challenge in biomimetic design is the search and identification of relevant solutions in nature...

  20. Laser technology in biomimetics basics and applications

    CERN Document Server

    Belegratis, Maria

    2013-01-01

    Lasers are progressively more used as versatile tools for fabrication purposes. The wide range of available powers, wavelengths, operation modes, repetition rates etc. facilitate the processing of a large spectrum of materials at exceptional precision and quality. Hence, manifold methods were established in the past and novel methods are continuously under development. Biomimetics, the translation from nature-inspired principles to technical applications, is strongly multidisciplinary. This field offers intrinsically a wide scope of applications for laser based methods regarding structuring and modification of materials. This book is dedicated to laser fabrication methods in biomimetics. It introduces both, a laser technology as well as an application focused approach.  The book covers the most important laser lithographic methods and various biomimetics application scenarios ranging from coatings and biotechnology to construction, medical applications and photonics.

  1. Research Development and Tendency of Biomimetic Robot Fish%仿生机器鱼研究进展及发展趋势

    Institute of Scientific and Technical Information of China (English)

    王扬威; 王振龙; 李健

    2011-01-01

    随着海洋资源开发和利用的深入,仿生机器鱼已成为水下机器人研究的热点问题.文中介绍了仿生机器鱼的分类,分析了各类型的游动特点.对鱼类游动机理和仿生机器鱼的研究现状进行了综述,总结了仿生机器鱼研究的关健技术和未来发展趋势.%Biomimetic robot fish has become a research focus in underwater robot domain with the exploitation and utilization of oceanic resources. This paper introduces the categories of biomimetic robot fish and analyses the characteristics of the various swimming types firstly. Then the research status in quo of fish swimming theory and biomimetic robot fish is reviewed. At last the key technologies and the developing tendency of biomimetic robot fish is discussed.

  2. Spatial distribution of proteins in the quagga mussel adhesive apparatus.

    Science.gov (United States)

    Rees, David J; Hanifi, Arash; Manion, Joseph; Gantayet, Arpita; Sone, Eli D

    2016-01-01

    The invasive freshwater mollusc Dreissena bugensis (quagga mussel) sticks to underwater surfaces via a proteinacious 'anchor' (byssus), consisting of a series of threads linked to adhesive plaques. This adhesion results in the biofouling of crucial underwater industry infrastructure, yet little is known about the proteins responsible for the adhesion. Here the identification of byssal proteins extracted from freshly secreted byssal material is described. Several new byssal proteins were observed by gel electrophoresis. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to characterize proteins in different regions of the byssus, particularly those localized to the adhesive interface. Byssal plaques and threads contain in common a range of low molecular weight proteins, while several proteins with higher mass were observed only in the plaque. At the adhesive interface, a plaque-specific ~8.1 kDa protein had a relative increase in signal intensity compared to the bulk of the plaque, suggesting it may play a direct role in adhesion.

  3. Tissue bionics: examples in biomimetic tissue engineering

    International Nuclear Information System (INIS)

    Many important lessons can be learnt from the study of biological form and the functional design of organisms as design criteria for the development of tissue engineering products. This merging of biomimetics and regenerative medicine is termed 'tissue bionics'. Clinically useful analogues can be generated by appropriating, modifying and mimicking structures from a diversity of natural biomatrices ranging from marine plankton shells to sea urchin spines. Methods in biomimetic materials chemistry can also be used to fabricate tissue engineering scaffolds with added functional utility that promise human tissues fit for the clinic

  4. Tissue bionics: examples in biomimetic tissue engineering.

    Science.gov (United States)

    Green, David W

    2008-09-01

    Many important lessons can be learnt from the study of biological form and the functional design of organisms as design criteria for the development of tissue engineering products. This merging of biomimetics and regenerative medicine is termed 'tissue bionics'. Clinically useful analogues can be generated by appropriating, modifying and mimicking structures from a diversity of natural biomatrices ranging from marine plankton shells to sea urchin spines. Methods in biomimetic materials chemistry can also be used to fabricate tissue engineering scaffolds with added functional utility that promise human tissues fit for the clinic.

  5. Adhesion and Cohesion

    Directory of Open Access Journals (Sweden)

    J. Anthony von Fraunhofer

    2012-01-01

    Full Text Available The phenomena of adhesion and cohesion are reviewed and discussed with particular reference to dentistry. This review considers the forces involved in cohesion and adhesion together with the mechanisms of adhesion and the underlying molecular processes involved in bonding of dissimilar materials. The forces involved in surface tension, surface wetting, chemical adhesion, dispersive adhesion, diffusive adhesion, and mechanical adhesion are reviewed in detail and examples relevant to adhesive dentistry and bonding are given. Substrate surface chemistry and its influence on adhesion, together with the properties of adhesive materials, are evaluated. The underlying mechanisms involved in adhesion failure are covered. The relevance of the adhesion zone and its importance with regard to adhesive dentistry and bonding to enamel and dentin is discussed.

  6. Integrating biologically inspired nanomaterials and table-top stereolithography for 3D printed biomimetic osteochondral scaffolds.

    Science.gov (United States)

    Castro, Nathan J; O'Brien, Joseph; Zhang, Lijie Grace

    2015-09-01

    The osteochondral interface of an arthritic joint is notoriously difficult to regenerate due to its extremely poor regenerative capacity and complex stratified architecture. Native osteochondral tissue extracellular matrix is composed of numerous nanoscale organic and inorganic constituents. Although various tissue engineering strategies exist in addressing osteochondral defects, limitations persist with regards to tissue scaffolding which exhibit biomimetic cues at the nano to micro scale. In an effort to address this, the current work focused on 3D printing biomimetic nanocomposite scaffolds for improved osteochondral tissue regeneration. For this purpose, two biologically-inspired nanomaterials have been synthesized consisting of (1) osteoconductive nanocrystalline hydroxyapatite (nHA) (primary inorganic component of bone) and (2) core-shell poly(lactic-co-glycolic) acid (PLGA) nanospheres encapsulated with chondrogenic transforming growth-factor β1 (TGF-β1) for sustained delivery. Then, a novel table-top stereolithography 3D printer and the nano-ink (i.e., nHA + nanosphere + hydrogel) were employed to fabricate a porous and highly interconnected osteochondral scaffold with hierarchical nano-to-micro structure and spatiotemporal bioactive factor gradients. Our results showed that human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and osteochondral differentiation were greatly improved in the biomimetic graded 3D printed osteochondral construct in vitro. The current work served to illustrate the efficacy of the nano-ink and current 3D printing technology for efficient fabrication of a novel nanocomposite hydrogel scaffold. In addition, tissue-specific growth factors illustrated a synergistic effect leading to increased cell adhesion and directed stem cell differentiation.

  7. Integrating biologically inspired nanomaterials and table-top stereolithography for 3D printed biomimetic osteochondral scaffolds.

    Science.gov (United States)

    Castro, Nathan J; O'Brien, Joseph; Zhang, Lijie Grace

    2015-09-01

    The osteochondral interface of an arthritic joint is notoriously difficult to regenerate due to its extremely poor regenerative capacity and complex stratified architecture. Native osteochondral tissue extracellular matrix is composed of numerous nanoscale organic and inorganic constituents. Although various tissue engineering strategies exist in addressing osteochondral defects, limitations persist with regards to tissue scaffolding which exhibit biomimetic cues at the nano to micro scale. In an effort to address this, the current work focused on 3D printing biomimetic nanocomposite scaffolds for improved osteochondral tissue regeneration. For this purpose, two biologically-inspired nanomaterials have been synthesized consisting of (1) osteoconductive nanocrystalline hydroxyapatite (nHA) (primary inorganic component of bone) and (2) core-shell poly(lactic-co-glycolic) acid (PLGA) nanospheres encapsulated with chondrogenic transforming growth-factor β1 (TGF-β1) for sustained delivery. Then, a novel table-top stereolithography 3D printer and the nano-ink (i.e., nHA + nanosphere + hydrogel) were employed to fabricate a porous and highly interconnected osteochondral scaffold with hierarchical nano-to-micro structure and spatiotemporal bioactive factor gradients. Our results showed that human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and osteochondral differentiation were greatly improved in the biomimetic graded 3D printed osteochondral construct in vitro. The current work served to illustrate the efficacy of the nano-ink and current 3D printing technology for efficient fabrication of a novel nanocomposite hydrogel scaffold. In addition, tissue-specific growth factors illustrated a synergistic effect leading to increased cell adhesion and directed stem cell differentiation. PMID:26234364

  8. Integrating biologically inspired nanomaterials and table-top stereolithography for 3D printed biomimetic osteochondral scaffolds

    Science.gov (United States)

    Castro, Nathan J.; O'Brien, Joseph; Zhang, Lijie Grace

    2015-08-01

    The osteochondral interface of an arthritic joint is notoriously difficult to regenerate due to its extremely poor regenerative capacity and complex stratified architecture. Native osteochondral tissue extracellular matrix is composed of numerous nanoscale organic and inorganic constituents. Although various tissue engineering strategies exist in addressing osteochondral defects, limitations persist with regards to tissue scaffolding which exhibit biomimetic cues at the nano to micro scale. In an effort to address this, the current work focused on 3D printing biomimetic nanocomposite scaffolds for improved osteochondral tissue regeneration. For this purpose, two biologically-inspired nanomaterials have been synthesized consisting of (1) osteoconductive nanocrystalline hydroxyapatite (nHA) (primary inorganic component of bone) and (2) core-shell poly(lactic-co-glycolic) acid (PLGA) nanospheres encapsulated with chondrogenic transforming growth-factor β1 (TGF-β1) for sustained delivery. Then, a novel table-top stereolithography 3D printer and the nano-ink (i.e., nHA + nanosphere + hydrogel) were employed to fabricate a porous and highly interconnected osteochondral scaffold with hierarchical nano-to-micro structure and spatiotemporal bioactive factor gradients. Our results showed that human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and osteochondral differentiation were greatly improved in the biomimetic graded 3D printed osteochondral construct in vitro. The current work served to illustrate the efficacy of the nano-ink and current 3D printing technology for efficient fabrication of a novel nanocomposite hydrogel scaffold. In addition, tissue-specific growth factors illustrated a synergistic effect leading to increased cell adhesion and directed stem cell differentiation.

  9. Proteins and Peptides in Biomimetic Polymeric Membranes

    DEFF Research Database (Denmark)

    Perez, Alfredo Gonzalez

    2013-01-01

    This chapter discusses recent advances and the main advantages of block copolymers for functional membrane protein reconstitution in biomimetic polymeric membranes. A rational approach to the reconstitution of membrane proteins in a functional form can be addressed by a more holistic view by usin...

  10. Major intrinsic proteins in biomimetic membranes.

    Science.gov (United States)

    Nielsen, Claus Hélix

    2010-01-01

    Biological membranes define the structural and functional boundaries in living cells and their organelles. The integrity of the cell depends on its ability to separate inside from outside and yet at the same time allow massive transport of matter in and out the cell. Nature has elegantly met this challenge by developing membranes in the form of lipid bilayers in which specialized transport proteins are incorporated. This raises the question: is it possible to mimic biological membranes and create a membrane based sensor and/or separation device? In the development of a biomimetic sensor/separation technology, a unique class of membrane transport proteins is especially interesting-the major intrinsic proteins (MIPs). Generally, MIPs conduct water molecules and selected solutes in and out of the cell while preventing the passage of other solutes, a property critical for the conservation of the cells internal pH and salt concentration. Also known as water channels or aquaporins they are highly efficient membrane pore proteins some of which are capable of transporting water at very high rates up to 10(9) molecules per second. Some MIPs transport other small, uncharged solutes, such as glycerol and other permeants such as carbon dioxide, nitric oxide, ammonia, hydrogen peroxide and the metalloids antimonite, arsenite, silicic and boric acid depending on the effective restriction mechanism of the protein. The flux properties of MIPs thus lead to the question ifMIPs can be used in separation devices or as sensor devices based on, e.g., the selective permeation of metalloids. In principle a MIP based membrane sensor/separation device requires the supporting biomimetic matrix to be virtually impermeable to anything but water or the solute in question. In practice, however, a biomimetic support matrix will generally have finite permeabilities to both electrolytes and non-electrolytes. The feasibility of a biomimetic MIP device thus depends on the relative transport

  11. International Conference on Underwater Environment

    CERN Document Server

    Jaulin, Luc; Creuze, Vincent; Debese, Nathalie; Quidu, Isabelle; Clement, Benoît; Billon-Coat, Annick

    2016-01-01

    This volume constitutes the results of the International Conference on Underwater Environment, MOQESM’14, held at “Le Quartz” Conference Center in Brest, France, on October 14-15, 2014, within the framework of the 9th Sea Tech Week, International Marine Science and Technology Event. The objective of MOQESM'14 was to bring together researchers from both academia and industry, interested in marine robotics and hydrography with application to the coastal environment mapping and underwater infrastructures surveys. The common thread of the conference is the combination of technical control, perception, and localization, typically used in robotics, with the methods of mapping and bathymetry. The papers presented in this book focus on two main topics. Firstly, coastal and infrastructure mapping is addressed, focusing not only on hydrographic systems, but also on positioning systems, bathymetry, and remote sensing. The proposed methods rely on acoustic sensors such as side scan sonars, multibeam echo sounders, ...

  12. Cooperative OFDM underwater acoustic communications

    CERN Document Server

    Cheng, Xilin; Cheng, Xiang

    2016-01-01

    Following underwater acoustic channel modeling, this book investigates the relationship between coherence time and transmission distances. It considers the power allocation issues of two typical transmission scenarios, namely short-range transmission and medium-long range transmission. For the former scenario, an adaptive system is developed based on instantaneous channel state information. The primary focus is on cooperative dual-hop orthogonal frequency division multiplexing (OFDM). This book includes the decomposed fountain codes designed to enable reliable communications with higher energy efficiency. It covers the Doppler Effect, which improves packet transmission reliability for effective low-complexity mirror-mapping-based intercarrier interference cancellation schemes capable of suppressing the intercarrier interference power level. Designed for professionals and researchers in the field of underwater acoustic communications, this book is also suitable for advanced-level students in electrical enginee...

  13. Sensor Network Architectures for Monitoring Underwater Pipelines

    OpenAIRE

    Imad Jawhar; Jameela Al-Jaroodi; Nader Mohamed; Liren Zhang

    2011-01-01

    This paper develops and compares different sensor network architecture designs that can be used for monitoring underwater pipeline infrastructures. These architectures are underwater wired sensor networks, underwater acoustic wireless sensor networks, RF (Radio Frequency) wireless sensor networks, integrated wired/acoustic wireless sensor networks, and integrated wired/RF wireless sensor networks. The paper also discusses the reliability challenges and enhancement approaches for these network...

  14. Insurance for autonomous underwater vehicles

    OpenAIRE

    Griffiths, G; N Bose; Ferguson, J.; Blidberg, D.R.

    2007-01-01

    The background and practice of insurance for autonomous underwater vehicles (AUVs) are examined. Key topics include: relationships between clients, brokers and underwriters; contract wording to provide appropriate coverage; and actions to take when an incident occurs. Factors that affect cost of insurance are discussed, including level of autonomy, team experience and operating environment. Four case studies from industry and academia illustrate how AUV insurance has worked in practice. The p...

  15. Taiwan's underwater cultural heritage documentation management

    Science.gov (United States)

    Tung, Y.-Y.

    2015-09-01

    Taiwan is an important trading and maritime channels for many countries since ancient time. Numerous relics lie underwater due to weather, wars, and other factors. In the year of 2006, Bureau of Cultural Heritage (BOCH) entrusted the Underwater Archaeological Team of Academia Sinica to execute the underwater archaeological investigation projects. Currently, we verified 78 underwater targets, with 78 site of those had been recognized as shipwrecks sites. Up to date, there is a collection of 638 underwater objects from different underwater archaeological sites. Those artefacts are distributed to different institutions and museums. As very diverse management methods/systems are applied for every individual institution, underwater cultural heritage data such as survey, excavation report, research, etc. are poorly organized and disseminated for use. For better communication regarding to Taiwan's underwater cultural heritage in every level, a universal format of documentation should be established. By comparing the existing checklist used in Taiwan with guidelines that are followed in other countries, a more intact and appropriate underwater cultural heritage condition documentation system can be established and adapted in Taiwan.

  16. Underwater photography - A visual survey method

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.

    of the photograph 176 (iv) Engineering - Inspection of underwater structures - Monitoring of pipelines and cables (v) Archaeological -Cataloguing of ancient submerged structures and shipwrecks. References...

  17. Fundamental Difficulties Associated With Underwater Wet Welding

    Directory of Open Access Journals (Sweden)

    Joshua E. Omajene,

    2014-06-01

    Full Text Available The offshore industries carry out welding activities in the wet environment. It is evident that the wet environments possess difficulties in carrying out underwater welding. Therefore there is the need to improve the quality of weld achieved in underwater welding. This paper investigates the difficulties associated with underwater welding. The objective of this research paper is to identify and analyze the different difficulties in underwater welding so as to make a clear background for further research to identifying the processes of eliminating these difficulties. The major difficulties in underwater welding are the cooling rate of the weld metal and arc stability during underwater wet welding at a higher depth. Methods of decreasing the cooling rate of weld metal and how to achieve arc stability are the major methods of approach. The result of welds achieved in underwater welding will be much improved as compared to air welding if the effects of the difficulties associated with underwater welding are eliminated. This will lead to a more robust welding activities being carried out underwater.

  18. Gecko-inspired bidirectional double-sided adhesives.

    Science.gov (United States)

    Wang, Zhengzhi; Gu, Ping; Wu, Xiaoping

    2014-05-14

    A new concept of gecko-inspired double-sided adhesives (DSAs) is presented. The DSAs, constructed by dual-angled (i.e. angled base and angled tip) micro-pillars on both sides of the backplane substrate, are fabricated by combinations of angled etching, mould replication, tip modification, and curing bonding. Two types of DSA, symmetric and antisymmetric (i.e. pillars are patterned symmetrically or antisymmetrically relative to the backplane), are fabricated and studied in comparison with the single-sided adhesive (SSA) counterparts through both non-conformal and conformal tests. Results indicate that the DSAs show controllable and bidirectional adhesion. Combination of the two pillar-layers can either amplify (for the antisymmetric DSA, providing a remarkable and durable adhesion capacity of 25.8 ± 2.8 N cm⁻² and a high anisotropy ratio of ∼8) or counteract (for the symmetric DSA, generating almost isotropic adhesion) the adhesion capacity and anisotropic level of one SSA (capacity of 16.2 ± 1.7 N cm⁻² and anisotropy ratio of ∼6). We demonstrate that these two DSAs can be utilized as a facile fastener for two individual objects and a small-scale delivery setup, respectively, complementing the functionality of the commonly studied SSA. As such, the double-sided patterning is believed to be a new branch in the further development of biomimetic dry adhesives.

  19. Analysis of the behaviours mediating barnacle cyprid reversible adhesion.

    Directory of Open Access Journals (Sweden)

    Nick Aldred

    , inherently sticky and exquisitely adapted for reversible adhesion underwater.

  20. Pressure sensitive microparticle adhesion through biomimicry of the pollen-stigma interaction.

    Science.gov (United States)

    Lin, Haisheng; Qu, Zihao; Meredith, J Carson

    2016-03-21

    Many soft biomimetic synthetic adhesives, optimized to support macroscopic masses (∼kg), have been inspired by geckos, insects and other animals. Far less work has investigated bioinspired adhesion that is tuned to micro- and nano-scale sizes and forces. However, such adhesive forces are extremely important in the adhesion of micro- and nanoparticles to surfaces, relevant to a wide range of industrial and biological systems. Pollens, whose adhesion is critical to plant reproduction, are an evolutionary-optimized system for biomimicry to engineer tunable adhesion between particles and micro-patterned soft matter surfaces. In addition, the adhesion of pollen particles is relevant to topics as varied as pollinator ecology, transport of allergens, and atmospheric phenomena. We report the first observation of structurally-derived pressure-sensitive adhesion of a microparticle by using the sunflower pollen and stigma surfaces as a model. This strong, pressure-sensitive adhesion results from interlocking between the pollen's conical spines and the stigma's receptive papillae. Inspired by this behavior, we fabricated synthetic polymeric patterned surfaces that mimic the stigma surface's receptivity to pollen. These soft mimics allow the magnitude of the pressure-sensitive response to be tuned by adjusting the size and spacing of surface features. These results provide an important new insight for soft material adhesion based on bio-inspired principles, namely that ornamented microparticles and micro-patterned surfaces can be designed with complementarity that enable a tunable, pressure-sensitive adhesion on the microparticle size and length scale. PMID:26883733

  1. Optical cell monitoring system for underwater targets

    Science.gov (United States)

    Moon, SangJun; Manzur, Fahim; Manzur, Tariq; Demirci, Utkan

    2008-10-01

    We demonstrate a cell based detection system that could be used for monitoring an underwater target volume and environment using a microfluidic chip and charge-coupled-device (CCD). This technique allows us to capture specific cells and enumerate these cells on a large area on a microchip. The microfluidic chip and a lens-less imaging platform were then merged to monitor cell populations and morphologies as a system that may find use in distributed sensor networks. The chip, featuring surface chemistry and automatic cell imaging, was fabricated from a cover glass slide, double sided adhesive film and a transparent Polymethlymetacrylate (PMMA) slab. The optically clear chip allows detecting cells with a CCD sensor. These chips were fabricated with a laser cutter without the use of photolithography. We utilized CD4+ cells that are captured on the floor of a microfluidic chip due to the ability to address specific target cells using antibody-antigen binding. Captured CD4+ cells were imaged with a fluorescence microscope to verify the chip specificity and efficiency. We achieved 70.2 +/- 6.5% capturing efficiency and 88.8 +/- 5.4% specificity for CD4+ T lymphocytes (n = 9 devices). Bright field images of the captured cells in the 24 mm × 4 mm × 50 μm microfluidic chip were obtained with the CCD sensor in one second. We achieved an inexpensive system that rapidly captures cells and images them using a lens-less CCD system. This microfluidic device can be modified for use in single cell detection utilizing a cheap light-emitting diode (LED) chip instead of a wide range CCD system.

  2. Advanced adhesives in electronics

    CERN Document Server

    Bailey, C

    2011-01-01

    Adhesives are widely used in the manufacture of electronic devices to act as passive and active components. Recently there has been considerable interest in the use of conductive adhesives. This book reviews key types of conductive adhesives, processing methods, properties and the way they can be modelled as well as potential applications.$bAdhesives for electronic applications serve important functional and structural purposes in electronic components and packaging, and have developed significantly over the last few decades. Advanced adhesives in electronics reviews recent developments in adhesive joining technology, processing and properties. The book opens with an introduction to adhesive joining technology for electronics. Part one goes on to cover different types of adhesive used in electronic systems, including thermally conductive adhesives, isotropic and anisotropic conductive adhesives and underfill adhesives for flip-chip applications. Part two focuses on the properties and processing of electronic ...

  3. Seeking Teachers for Underwater Robotics PD Program

    Science.gov (United States)

    McGrath, Beth; Sayres, Jason

    2012-01-01

    With funding from the National Science Foundation (NSF), ITEEA members will contribute to the development of a hybrid professional development program designed to facilitate the scale-up of an innovative underwater robotics curriculum. WaterBotics[TM] is an underwater robotics curriculum that targets students in middle and high school classrooms…

  4. 29 CFR 1926.912 - Underwater blasting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Underwater blasting. 1926.912 Section 1926.912 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.912 Underwater blasting. (a) A blaster shall conduct all blasting operations, and no shot shall be fired...

  5. Acoustic signal analysis of underwater elastic cylinder

    Institute of Scientific and Technical Information of China (English)

    LI Xiukun; YANG Shi'e

    2001-01-01

    The echoes of underwater elastic cylinder comprise two types of acoustic components: Geometrical scattering waves and elastic scattering waves. The transfer function is appropriate to characterize the echo of targets. And the discrete wavelet transform of amplitude spectrum is presented and used to identify the resonant components of underwater targets.PACS numbers: 43.30, 43.60

  6. Underwater noise from a wave energy converter

    DEFF Research Database (Denmark)

    Tougaard, Jakob

    A recent addition to the anthropogenic sources of underwater noise is offshore wave energy converters. Underwater noise was recorded from the Wavestar wave energy converter located at Hastholm, Denmark (57°7.73´N, 8°37.23´E). The Wavestar is a full-scale test and demonstration converter...

  7. Coefficient of variation of underwater irradiance fluctuations

    Science.gov (United States)

    Weber, V. L.

    2010-06-01

    We consider underwater sunlight fluctuations in the case of a one-dimensional irregular sea surface. Several rigorous and approximate models are proposed, which make it possible to analytically treat and physically explain the dependence of the coefficient of variation of the underwater irradiance on the depth, the wind velocity, and optical parameters of the sea water.

  8. The Top of the Biomimetic Triangle

    Institute of Scientific and Technical Information of China (English)

    Andrei P. Sommer; Dan Zhu; Matthias Wiora; Hans-Joerg Fecht

    2008-01-01

    There is increasing observational evidence indicating that crystalline interfacial water layers play a central role in evolution and biology. For instance in cellular recognition processes, in particular during first contact events, where cells decide upon survival or entering apoptosis. Understanding water layers is thus crucial in biomedical engineering, specifically in the design of biomaterials inspired by biomimetic principles. Whereas there is ample experimental evidence for crystalline interfacial water layers on surfaces in air, their subaquatic presence could not be verified directly, so far. Analysing a polarity dependent asym- metry in the surface conductivity on hydrogenated nanocrystalline diamond, we show that crystalline interfacial water layers persist subaquatically. Nanoscopic interfacial water layers with an order different from that of bulk water have been identified at room temperature on both hydrophilic and hydrophobic model surfaces - in air and subaquatically. Their generalization and systematic inclusion into the catalogue of physical and chemical determinants of biocompatibility complete the biomimetic triangle.

  9. Green Tribology Biomimetics, Energy Conservation and Sustainability

    CERN Document Server

    Bhushan, Bharat

    2012-01-01

    Tribology is the study of friction, wear and lubrication. Recently, the concept of “green tribology” as “the science and technology of the tribological aspects of ecological balance and of environmental and biological impacts” was introduced. The field of green tribology includes tribological technology that mimics living nature (biomimetic surfaces) and thus is expected to be environmentally friendly, the control of friction and wear that is of importance for energy conservation and conversion, environmental aspects of lubrication and surface modification techniques, and tribological aspects of green applications such as wind-power turbines or solar panels. This book is the first comprehensive volume on green tribology. The chapters are prepared by leading experts in their fields and cover such topics as biomimetics, environmentally friendly lubrication, tribology of wind turbines and renewable sources of energy, and ecological impact of new technologies of surface treatment.

  10. ROV Based Underwater Blurred Image Restoration

    Institute of Scientific and Technical Information of China (English)

    LIU Zhishen; DING Tianfu; WANG Gang

    2003-01-01

    In this paper, we present a method of ROV based image processing to restore underwater blurry images from the theory of light and image transmission in the sea. Computer is used to simulate the maximum detection range of the ROV under different water body conditions. The receiving irradiance of the video camera at different detection ranges is also calculated. The ROV's detection performance under different water body conditions is given by simulation. We restore the underwater blurry images using the Wiener filter based on the simulation. The Wiener filter is shown to be a simple useful method for underwater image restoration in the ROV underwater experiments. We also present examples of restored images of an underwater standard target taken by the video camera in these experiments.

  11. Non-Smooth Morphologies of Typical Plant Leaf Surfaces and Their Anti-Adhesion Effects

    Institute of Scientific and Technical Information of China (English)

    Lu-quan Ren; Shu-jie Wang; Xi-mei Tian; Zhi-wu Han; Lin-na Yan; Zhao-mei Qiu

    2007-01-01

    The micromorphologies of surfaces of several typical plant leaves were investigated by scanning electron microscopy(SEM).Different non-smooth surface characteristics were described and classified.The hydrophobicity and anti-adhesion of non-smooth leaf surfaces were quantitatively measured.Results show that the morphology of epidermal cells and the morphology and distribution density of epicuticular wax directly affect the hydrophobicity and anti-adhesion.The surface with uniformly distributed convex units shows the best anti-adhesion,and the surface with regularly arranged trellis units displays better anti-adhesion.In contrast,the surface with randomly distributed hair units performs relatively bad anti-adhesion.The hydrophobic models of papilla-ciliary and fold-setal non-smooth surfaces were set up to determine the impacts of geometric parameters on the hydrophobicity.This study may provide an insight into surface machine molding and apparent morphology design for biomimetics engineering.

  12. Action of Chicory Fructooligosaccharides on Biomimetic Membranes

    OpenAIRE

    Barbosa, A. F.; Henrique, R. S.; A. S. Lucho; V. Paffaro; J.M. Schneedorf

    2014-01-01

    Fructooligosaccharides from chicory (FOSC) are functional prebiotic foods recognized to exert several well-being effects in human health and animal production, as decreasing blood lipids, modulating the gut immune system, enhancing mineral bioavailability, and inhibiting microbial growth, among others. Mechanisms of actions directly on cell metabolism and structure are however little known. In this sense this work was targeted to investigate the interaction of FOSC with biomimetic membranes (...

  13. Design of graded biomimetic osteochondral composite scaffolds

    OpenAIRE

    Tampieri, Anna; Sandri, Monica; Landi, Elena; Pressato, Daniele; Francioli, Silvia; Quarto, Rodolfo; Martin, Ivan

    2008-01-01

    With the ultimate goal to generate suitable materials for the repair of osteochondral defects, in this work we aimed at developing composite osteochondral scaffolds organized in different integrated layers, with features which are biomimetic for articular cartilage and subchondral bone and can differentially support formation of such tissues. A biologically inspired mineralization process was first developed to nucleate Mg-doped hydroxyapatite crystals on type I collagen fibers during their s...

  14. Underwater YAG laser welding technique

    International Nuclear Information System (INIS)

    When planning preventive maintenance of reactor components using welding, it is necessary to consider special environments such as narrow space or difficult accessibility while minimizing exposure to radiation in the reactor pressure vessel. Toshiba has developed an underwater neodymium: yttrium-aluminum-garnet (Nd: YAG) laser welding technique. The features of this welding technique are low-heat-input welding and compact welding machine dimensions for welding in narrow spaces. This paper provides a summary of the new welding technique as a reliable welding technology. (author)

  15. Underwater cultural heritage (Guest editorial)

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Vora, K.H.

    , VOL. 86, NO. 9, 10 MAY 2004 In this issue Underwater cultural heritage Curiosity to explore the past through artifacts, stories and legends, passed over generations, is the essence of archa e o - logy. Every object uncovered from an ancient... site represents a moment frozen in time and e ach of them opens new wi n dows to the past. This curiosity to e x plore the past and open up time cap - sules that help to solve the archaeological ji g saw, is what has driven many archaeo - l o gists...

  16. Biomimetic Composite Structural T-joints

    Institute of Scientific and Technical Information of China (English)

    Vimal Kumar Thummalapalli; Steven L.Donaldson

    2012-01-01

    Biological structural fixed joints exhibit unique attributes,including highly optimized fiber paths which minimize stress concentrations.In addition,since the joints consist of continuous,uncut fiber architectures,the joints enable the organism to transport information and chemicals from one part of the body to the other.To the contrary,sections of man-made composite material structures are often joined using bolted or bonded joints,which involve low strength and high stress concentrations.These methods are also expensive to achieve.Additional functions such as fluid transport,electrical signal delivery,and thermal conductivity across the joints typically require parasitic tubes,wires,and attachment clips.By using the biomimetic methods,we seek to overcome the limitations which are present in the conventional methods. In the present work,biomimetic co-cured composite sandwich T-joints were constructed using unidirectional glass fiber,epoxy resin,and structural foam.The joints were fabricated using the wet lay-up vacuum bag resin infusion method.Foam sandwich T-joints with multiple continuous fiber architectures and sandwich foam thickness were prepared.The designs were tested in quasi-static bending using a mechanical load frame.The significantweight savings using the biomimetic approaches is discussed,as well as a comparison of failure modes versus architecture is described.

  17. Biomimetic nanoparticles: preparation, characterization and biomedical applications

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2010-04-01

    Full Text Available Ana Maria Carmona-RibeiroBiocolloids Lab, Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, BrazilAbstract: Mimicking nature is a powerful approach for developing novel lipid-based devices for drug and vaccine delivery. In this review, biomimetic assemblies based on natural or synthetic lipids by themselves or associated to silica, latex or drug particles will be discussed. In water, self-assembly of lipid molecules into supramolecular structures is fairly well understood. However, their self-assembly on a solid surface or at an interface remains poorly understood. In certain cases, hydrophobic drug granules can be dispersed in aqueous solution via lipid adsorption surrounding the drug particles as nanocapsules. In other instances, hydrophobic drug molecules attach as monomers to borders of lipid bilayer fragments providing drug formulations that are effective in vivo at low drug-to-lipid-molar ratio. Cationic biomimetic particles offer suitable interfacial environment for adsorption, presentation and targeting of biomolecules in vivo. Thereby antigens can effectively be presented by tailored biomimetic particles for development of vaccines over a range of defined and controllable particle sizes. Biomolecular recognition between receptor and ligand can be reconstituted by means of receptor immobilization into supported lipidic bilayers allowing isolation and characterization of signal transduction steps.Keywords: cationic lipid, phospholipids, bilayer fragments, vesicles, silica, polymeric particles, antigens, novel cationic immunoadjuvants, drugs

  18. Adhesion in microelectronics

    CERN Document Server

    Mittal, K L

    2014-01-01

    This comprehensive book will provide both fundamental and applied aspects of adhesion pertaining to microelectronics in a single and easily accessible source. Among the topics to be covered include; Various theories or mechanisms of adhesionSurface (physical or chemical) characterization of materials as it pertains to adhesionSurface cleaning as it pertains to adhesionWays to improve adhesionUnraveling of interfacial interactions using an array of pertinent techniquesCharacterization of interfaces / interphasesPolymer-polymer adhesionMetal-polymer adhesion  (metallized polymers)Polymer adhesi

  19. A tailless timing belt climbing platform utilizing dry adhesives with mushroom caps

    Science.gov (United States)

    Krahn, J.; Liu, Y.; Sadeghi, A.; Menon, C.

    2011-11-01

    In many instances, a climbing robot that utilizes dry adhesives as an attachment method may be found to be very useful due to the inherent nature of biomimetic fibrillar dry adhesives in the applications of space, security, surveillance and nuclear reactor cleaning and maintenance. In this paper, a novel tank-like modular robot is developed that does not require a tail to provide a preload to the front of the robot while climbing. Biomimetic fibrillar dry adhesives with mushroom caps manufactured into belts are used as an attachment method. The manufacturing of the dry adhesive belts is discussed and the adhesion properties are examined. The timing belt based climbing platform (TBCP-II) utilizes two tank-like modules connected with an active joint with continual surface-robot distance measuring providing feedback for active adhesive preloading. The mechanical, electronic and software design is discussed. Reliable vertical surface climbing is achieved and the preloading strategy and response is examined. TBCP-II is shown to be capable of both horizontal to vertical and vertical to horizontal surface transfers over both inside and outside corners.

  20. Molecular mechanics of mussel adhesion proteins

    Science.gov (United States)

    Qin, Zhao; Buehler, Markus J.

    2014-01-01

    Mussel foot protein (mfp), a natural glue produced by marine mussel, is an intriguing material because of its superior ability for adhesion in various environments. For example, a very small amount of this material is sufficient to affix a mussel to a substrate in water, providing structural support under extreme forces caused by the dynamic effects of waves. Towards a more complete understanding of its strength and underwater workability, it is necessary to understand the microscropic mechanisms by which the protein structure interacts with various substrates. However, none of the mussel proteins' structure is known, preventing us from directly using atomistic modeling to probe their structural and mechanical properties. Here we use an advanced molecular sampling technique to identify the molecular structures of two mussel foot proteins (mfp-3 and mfp-5) and use those structures to study their mechanics of adhesion, which is then incorporated into a continuum model. We calculate the adhesion energy of the mussel foot protein on a silica substrate, compute the adhesion strength based on results obtained from molecular modeling, and compare with experimental data. Our results show good agreement with experimental measurements, which validates the multiscale model. We find that the molecular structure of the folded mussel foot protein (ultimately defined by its genetic sequence) favors strong adhesion to substrates, where L-3,4-dihydroxyphenylalanine (or DOPA) protein subunits work in a cooperative manner to enhance adhesion. Our experimental data suggests a peak attachment force of 0.4±0.1 N, which compares favorably with the prediction from the multiscale model of Fc=0.21-0.33 N. The principles learnt from those results could guide the fabrication of new interfacial materials (e.g. composites) to integrate organic with inorganic surfaces in an effective manner.

  1. Underwater camera with depth measurement

    Science.gov (United States)

    Wang, Wei-Chih; Lin, Keng-Ren; Tsui, Chi L.; Schipf, David; Leang, Jonathan

    2016-04-01

    The objective of this study is to develop an RGB-D (video + depth) camera that provides three-dimensional image data for use in the haptic feedback of a robotic underwater ordnance recovery system. Two camera systems were developed and studied. The first depth camera relies on structured light (as used by the Microsoft Kinect), where the displacement of an object is determined by variations of the geometry of a projected pattern. The other camera system is based on a Time of Flight (ToF) depth camera. The results of the structural light camera system shows that the camera system requires a stronger light source with a similar operating wavelength and bandwidth to achieve a desirable working distance in water. This approach might not be robust enough for our proposed underwater RGB-D camera system, as it will require a complete re-design of the light source component. The ToF camera system instead, allows an arbitrary placement of light source and camera. The intensity output of the broadband LED light source in the ToF camera system can be increased by putting them into an array configuration and the LEDs can be modulated comfortably with any waveform and frequencies required by the ToF camera. In this paper, both camera were evaluated and experiments were conducted to demonstrate the versatility of the ToF camera.

  2. Adhesion beyond the interface: Molecular adaptations of the mussel byssus to the intertidal zone

    Science.gov (United States)

    MIller, Dusty Rose

    The California mussel, Mytilus californianus, adheres robustly in the high-energy and oxidizing intertidal zone with a fibrous holdfast called the byssus using 3,4-dihydroxyphenyl-L-alanine (Dopa)-containing adhesive mussel foot proteins (mfps). There are many supporting roles to mussel adhesion that are intimately linked and ultimately responsible for mussel byssus's durable and dynamic adhesion. This dissertation explores these supporting mechanisms, including delivery of materials underwater, iron binding, friction, and antioxidant activity. As the outermost covering of the byssus, the cuticle deserves particular attention for its supporting roles to adhesion including the high stiffness and extensibility of the M. californianus byssal cuticle, which make it one of the most energy tolerant materials known. The cuticle's matrix-granule composite structure contributes to its toughness by microcracking between its harder granules and softer matrix. We investigated delivery of cuticular material underwater, cohesion of cuticle proteins, and surface damage mitigation by cuticle protein-based coacervates. To investigate underwater material delivery, we made cuticle matrix mimics by coacervating a key cuticular protein, Mytilus californianus foot protein 1, mfp-1, with hyaluronic acid. These matrix mimics coacervated over a wide range of solution conditions, delivered concentrated material, settled on and coated surfaces underwater. Because the granules are composed of mfp-1 condensed with iron, we used the surface forces apparatus to investigate the effects of iron on the cohesion of mfp-1 from two different species of mussels and found that subtle sequence variations modulate cohesion. Using the coacervate matrix mimics and, modeling the granules as a hard surface (mica), we investigated the wear protection of coacervated mfp-1/HA to mica under frictional shear and found that preventing wear depends critically on the presence of Dopa groups. In addition to cuticle

  3. Towards the LIVING envelope: Biomimetics for building envelope adaptation

    NARCIS (Netherlands)

    Badarnah Kadri, L.

    2012-01-01

    Several biomimetic design strategies are available for various applications, though the research on biomimetics as a design tool in architecture is still challenging. This is due to a lack of systematic design tools required for identifying relevant organisms, or natural systems, and abstracting the

  4. 仿生机器鱼研究的进展与分析%RESEARCH DEVELOPMENT AND ANALYSIS OF BIOMIMETIC ROBOTIC FISH

    Institute of Scientific and Technical Information of China (English)

    魏清平; 王硕; 谭民; 王宇

    2012-01-01

    仿生机器鱼,作为一种高效、高机动的水下机器人,得到研究人员的广泛关注.介绍了国内外在仿生机器鱼推进机理和系统研制方面的主要研究进展.通过分析,归纳总结了仿生机器鱼研究的主要问题,并重点讨论了推进机理、机构优化和运动控制的研究思路.%Biomimetic robotic fish, as one kind of highly efficient and highly maneuverable underwater robots, achieved the widespread concern of researchers. In this paper, the major research developments in propulsion mechanism and system development of biomimetic robotic fish were presented. Through the analysis, the main issues of biomimetic robotic fish were summarized and the research ideas of propulsion mechanism, mechanism optimization and motion control were also emphatically discussed.

  5. Biomimetics: forecasting the future of science, engineering, and medicine.

    Science.gov (United States)

    Hwang, Jangsun; Jeong, Yoon; Park, Jeong Min; Lee, Kwan Hong; Hong, Jong Wook; Choi, Jonghoon

    2015-01-01

    Biomimetics is the study of nature and natural phenomena to understand the principles of underlying mechanisms, to obtain ideas from nature, and to apply concepts that may benefit science, engineering, and medicine. Examples of biomimetic studies include fluid-drag reduction swimsuits inspired by the structure of shark's skin, velcro fasteners modeled on burrs, shape of airplanes developed from the look of birds, and stable building structures copied from the backbone of turban shells. In this article, we focus on the current research topics in biomimetics and discuss the potential of biomimetics in science, engineering, and medicine. Our report proposes to become a blueprint for accomplishments that can stem from biomimetics in the next 5 years as well as providing insight into their unseen limitations.

  6. Electrospun biomimetic scaffold of hydroxyapatite/chitosan supports enhanced osteogenic differentiation of mMSCs

    Science.gov (United States)

    Peng, Hongju; Yin, Zi; Liu, Huanhuan; Chen, Xiao; Feng, Bei; Yuan, Huihua; Su, Bo; Ouyang, Hongwei; Zhang, Yanzhong

    2012-12-01

    Engaging functional biomaterial scaffolds to regulate stem cell differentiation has drawn a great deal of attention in the tissue engineering and regenerative medicine community. In this study, biomimetic composite nanofibrous scaffolds of hydroxyapatite/chitosan (HAp/CTS) were prepared to investigate their capacity for inducing murine mesenchymal stem cells (mMSCs) to differentiate into the osteogenic lineage, in the absence and presence of an osteogenic supplementation (i.e., ascorbic acid, β-glycerol phosphate, and dexamethasone), respectively. Using electrospun chitosan (CTS) nanofibrous scaffolds as the control, cell morphology, growth, specific osteogenic genes expression, and quantified proteins secretion on the HAp/CTS scaffolds were sequentially examined and assessed. It appeared that the HAp/CTS scaffolds supported better attachment and proliferation of the mMSCs. Most noteworthy was that in the absence of the osteogenic supplementation, expression of osteogenic genes including collagen I (Col I), runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and osteocalcin (OCN) were significantly upregulated in mMSCs cultured on the HAp/CTS nanofibrous scaffolds. Also increased secretion of the osteogenesis protein markers of alkaline phosphatase and collagen confirmed that the HAp/CTS nanofibrous scaffold markedly promoted the osteogenic commitment in the mMSCs. Moreover, the presence of osteogenic supplementation proved an enhanced efficacy of mMSC osteogenesis on the HAp/CTS nanofibrous scaffolds. Collectively, this study demonstrated that the biomimetic nanofibrous HAp/CTS scaffolds could support and enhance the adhesion, proliferation, and particularly osteogenic differentiation of the mMSCs. It also substantiated the potential of using biomimetic nanofibrous scaffolds of HAp/CTS for functional bone repair and regeneration applications.

  7. 4th Pacific Rim Underwater Acoustics Conference

    CERN Document Server

    Xu, Wen; Cheng, Qianliu; Zhao, Hangfang

    2016-01-01

    These proceedings are a collection of 16 selected scientific papers and reviews by distinguished international experts that were presented at the 4th Pacific Rim Underwater Acoustics Conference (PRUAC), held in Hangzhou, China in October 2013. The topics discussed at the conference include internal wave observation and prediction; environmental uncertainty and coupling to sound propagation; environmental noise and ocean dynamics; dynamic modeling in acoustic fields; acoustic tomography and ocean parameter estimation; time reversal and matched field processing; underwater acoustic localization and communication as well as measurement instrumentations and platforms. These proceedings provide insights into the latest developments in underwater acoustics, promoting the exchange of ideas for the benefit of future research.

  8. Enhancing Osteoconduction of PLLA-Based Nanocomposite Scaffolds for Bone Regeneration Using Different Biomimetic Signals to MSCs

    Directory of Open Access Journals (Sweden)

    Nicola Baldini

    2012-02-01

    Full Text Available In bone engineering, the adhesion, proliferation and differentiation of mesenchymal stromal cells rely on signaling from chemico-physical structure of the substrate, therefore prompting the design of mimetic “extracellular matrix”-like scaffolds. In this study, three-dimensional porous poly-L-lactic acid (PLLA-based scaffolds have been mixed with different components, including single walled carbon nanotubes (CNT, micro-hydroxyapatite particles (HA, and BMP2, and treated with plasma (PT, to obtain four different nanocomposites: PLLA + CNT, PLLA + CNTHA, PLLA + CNT + HA + BMP2 and PLLA + CNT + HA + PT. Adult bone marrow mesenchymal stromal cells (MSCs were derived from the femur of orthopaedic patients, seeded on the scaffolds and cultured under osteogenic induction up to differentiation and mineralization. The release of specific metabolites and temporal gene expression profiles of marrow-derived osteoprogenitors were analyzed at definite time points, relevant to in vitro culture as well as in vivo differentiation. As a result, the role of the different biomimetic components added to the PLLA matrix was deciphered, with BMP2-added scaffolds showing the highest biomimetic activity on cells differentiating to mature osteoblasts. The modification of a polymeric scaffold with reinforcing components which also work as biomimetic cues for cells can effectively direct osteoprogenitor cells differentiation, so as to shorten the time required for mineralization.

  9. Biomimetic Mineralized Hierarchical Graphene Oxide/Chitosan Scaffolds with Adsorbability for Immobilization of Nanoparticles for Biomedical Applications.

    Science.gov (United States)

    Xie, Chaoming; Lu, Xiong; Han, Lu; Xu, Jielong; Wang, Zhenming; Jiang, Lili; Wang, Kefeng; Zhang, Hongping; Ren, Fuzeng; Tang, Youhong

    2016-01-27

    Biomimetic calcium phosphate mineralized graphene oxide/chitosan (GO/CS) scaffolds with hierarchical structures were developed. First, GO/CS scaffolds with large micropores (∼300 μm) showed high mechanical strength due to the electrostatic interaction between the oxygen-containing functional groups of GO and the amine groups of CS. Second, octacalcuim phosphate (OCP) with porous structures (∼1 μm) was biomimetically mineralized on the surfaces of the GO/CS scaffolds (OCP-GO/CS). The hierarchical microporous structures of OCP-GO/CS scaffolds provide a suitable environment for cell adhesion and growth. The scaffolds have exceptional adsorbability of nanoparticles. Bone morphogenetic protein-2 (BMP-2)-encapsulated bovine serum albumin (BSA) nanoparticles and Ag nanoparticles (Ag-NPs) were adsorbed in the scaffolds for enhancement of osteoinductivity and antibacterial properties, respectively. Antibacterial tests showed that the scaffolds exhibited high antibacterial properties against both Escherichia coli and Staphylococcus epidermidis. In vitro and in vivo experiments revealed that the scaffolds have good biocompatibility, enhanced bone marrow stromal cells proliferation and differentiation, and induced bone tissue regeneration. Thus, the biomimetic OCP-GO/CS scaffolds with immobilized growth factors and antibacterial agents might be excellent candidates for bone tissue engineering. PMID:26710937

  10. Rapid biomimetic mineralization of collagen fibrils and combining with human umbilical cord mesenchymal stem cells for bone defects healing.

    Science.gov (United States)

    Ye, Bihua; Luo, Xueshi; Li, Zhiwen; Zhuang, Caiping; Li, Lihua; Lu, Lu; Ding, Shan; Tian, Jinhuan; Zhou, Changren

    2016-11-01

    Collagen biomineralization is regulated by complicated interactions between the collagen matrix and non-collagenous extracellular proteins. Here, the use of sodium tripolyphosphate to simulate the templating functional motif of the C-terminal fragment of non-collagenous proteins is reported, and a low molecular weight polyacrylic acid served as a sequestration agent to stabilize amorphous calcium phosphate into nanoprecursors. Self-assembled collagen fibrils served as a fixed template for achieving rapid biomimetic mineralization in vitro. Results demonstrated that, during the mineralization process, intrafibrillar and extrafibrillar hydroxyapatite mineral with collagen fibrils formed and did so via bottom-up nanoparticle assembly based on the non-classical crystallization approach in the presence of these dual biomimetic functional analogues. In vitro human umbilical cord mesenchymal stem cell (hUCMSC) culture found that the mineralized scaffolds have a better cytocompatibility in terms of cell viability, adhesion, proliferation, and differentiation into osteoblasts. A rabbit femoral condyle defect model was established to confirm the ability of the n-HA/collagen scaffolds to facilitate bone regeneration and repair. The images of gross anatomy, MRI, CT and histomorphology taken 6 and 12weeks after surgery showed that the biomimetic mineralized collagen scaffolds with hUCMSCs can promote the healing speed of bone defects in vivo, and both of the scaffolds groups performing better than the bone defect control group. As new bone tissue formed, the scaffolds degraded and were gradually absorbed. All these results demonstrated that both of the scaffolds and cells have better histocompatibility. PMID:27523994

  11. AURP: An AUV-Aided Underwater Routing Protocol for Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sunghwan Kim

    2012-02-01

    Full Text Available Deploying a multi-hop underwater acoustic sensor network (UASN in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol, which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs. In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved.

  12. AURP: an AUV-aided underwater routing protocol for underwater acoustic sensor networks.

    Science.gov (United States)

    Yoon, Seokhoon; Azad, Abul K; Oh, Hoon; Kim, Sunghwan

    2012-01-01

    Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved.

  13. AURP: an AUV-aided underwater routing protocol for underwater acoustic sensor networks.

    Science.gov (United States)

    Yoon, Seokhoon; Azad, Abul K; Oh, Hoon; Kim, Sunghwan

    2012-01-01

    Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved. PMID:22438740

  14. Computational Research on Modular Undulating Fin for Biorobotic Underwater Propulsor

    Institute of Scientific and Technical Information of China (English)

    Yong-hua Zhang; Lai-bing Jia; Shi-wu Zhang; Jie Yang; K.H.Low

    2007-01-01

    Biomimetic design employs the principles of nature to solve engineering problems.Such designs which are hoped to be quick,efficient,robust,and versatile,have taken advantage of optimization via natural selection.In the present research.an environment-friendly propulsion system mimicking undulating fins of stingray was built.A non-conventional method was considered to model the flexibility of the fins of stingray.A two-degree-of-freedom mechanism comprised of several linkages was designed and constructed to mimic the actual flexible fin.The driving linkages were used to form a mechanical fin consisting of several fin segments,which are able to produce undulations,similar to those produced by the actual fins.Owing to the modularity of the design of the mechanical fin,various undulating patterns can be realized.Some qualitative observations,obtained by experiments,predicted that the thrusts produced by the mechanical fin are different among various undulating patterns.To fully understand this experimental phenomenon is very important for better performance and energy saving for our biorobotic underwater propulsion system.Here,four basic undulating patterns of the mechanical fin were performed using two-dimensional unsteady computational fluid dynamics(CFD)method.An unstructured,grid-based,unsteady Navier-Stokes solver with automatic adaptive re-meshing was used to compute the unsteady flow around the fin through twenty complete cycles.The pressure distribution on fin surface was computed and integrated to provide fin forces which were decomposed into lift and thrust.The pressure force and friction force were also computed throughout the swimming cycle.Finally,vortex contour maps of these four basic fin undulating patterns were displayed and compared.

  15. Towards biomimetic scaffolds: anhydrous scaffold fabrication from biodegradable amine-reactive diblock copolymers.

    Science.gov (United States)

    Hacker, Michael; Tessmar, Jörg; Neubauer, Markus; Blaimer, Andrea; Blunk, Torsten; Göpferich, Achim; Schulz, Michaela B

    2003-11-01

    The development of biomimetic materials and their processing into three-dimensional cell carrying scaffolds is one promising tissue engineering strategy to improve cell adhesion, growth and differentiation on polymeric constructs developing mature and viable tissue. This study was concerned with the fabrication of scaffolds made from amine-reactive diblock copolymers, N-succinimidyl tartrate monoamine poly(ethylene glycol)-block-poly(D,L-lactic acid), which are able to suppress unspecific protein adsorption and to covalently bind proteins or peptides. An appropriate technique for their processing had to be both anhydrous, to avoid hydrolysis of the active ester, and suitable for the generation of interconnected porous structures. Attempts to fabricate scaffolds utilizing hard paraffin microparticles as hexane-extractable porogens failed. Consequently, a technique was developed involving lipid microparticles, which served as biocompatible porogens on which the scaffold forming polymer was precipitated in the porogen extraction media (n-hexane). Porogen melting during the extraction and polymer precipitation step led to an interconnected network of pores. Suitable lipid mixtures and their melting points, extraction conditions (temperature and time) and a low-toxic polymer solvent system were determined for their use in processing diblock copolymers of different molecular weights (22 and 42 kDa) into highly porous off-the-shelf cell carriers ready for easy surface modification towards biomimetic scaffolds. Insulin was employed to demonstrate the principal of instant protein coupling to a prefabricated scaffold. PMID:12922156

  16. Biomimetic/Bioinspired Design of Enzyme@capsule Nano/Microsystems.

    Science.gov (United States)

    Shi, J; Jiang, Y; Zhang, S; Yang, D; Jiang, Z

    2016-01-01

    Enzyme@capsule nano/microsystems, which refer to the enzyme-immobilized capsules, have received tremendous interest owing to the combination of the high catalytic activities of encapsulated enzymes and the hierarchical structure of the capsule. The preparation of capsules and simultaneous encapsulation of enzymes is recognized as the core process for the rational design and construction of enzyme@capsule nano/microsystems. The strategy used has three major steps: (a) generation of the templates, (b) surface coating on the templates, and (c) removal of the templates, and it has been proven to be effective and versatile for the construction of enzyme@capsule nano/microsystems. Several conventional methods, including layer-by-layer assembly of polyelectrolytes, liquid crystalline templating method, etc., were used to design and construct enzyme@capsule nano/microsystems, but these have two major drawbacks. One is the low mechanical stability of the systems and the second is the harsh conditions used in the construction process. Learning from nature, several biomimetic/bioinspired methods such as biomineralization, biomimetic/bioinspired adhesion, and their combination have been exploited for the construction of enzyme@capsule nano/microsystems. In this chapter, we will present a general protocol for the construction of enzyme@capsule nano/microsystems using the latter approach. Some suggestions for improved design, construction, and characterization will also be presented with detailed procedures for specific examples.

  17. Underwater explosions and cavitation phenomena

    International Nuclear Information System (INIS)

    Some aspects of underwater explosions and cavitation phenomena have been studied by using a thermodynamic equation of state for water and a one-dimensional Lagrangian hydrocode. The study showed that surface cavitation is caused by the main blast wave and a bubble pulse from rebound of a release wave moving toward the center of the exploding bubble. Gravity has little effect on the surface cavitation. In nuclear explosions the bubble is bounded by a two-phase region rather than a gas-water interface. The two-phase region cavitates as the bubble expands, changing the optical absorption coefficient by many orders of magnitude and significantly affecting the optical signature. In assessing cavitation damage, it is concluded that a water jet of unstable bubble collapse erodes solid walls. The study leads to suggestions for future research

  18. Autonomous underwater riser inspection tool

    Energy Technology Data Exchange (ETDEWEB)

    Camerini, Claudio; Marnet, Robson [Petrobras SA, (Brazil); Freitas, Miguel; Von der Weid, Jean Pierre [CPTI/PUC-Rio, Rio de Janeiro, (Brazil); Artigas Lander, Ricardo [EngeMOVI, Curitiba, (Brazil)

    2010-07-01

    The detection of damage on the riser is a serious concern for pipeline companies. Visual examinations by remotely operated vehicle (ROV) are presently carried out to detect the defects but this process has limitations and is expensive. This paper presents the development of a new tool to ensure autonomous underwater riser inspection (AURI) that uses the riser itself for guidance. The AURI, which is autonomous in terms of control and power supply, is equipped with several cameras that perform a complete visual inspection of the riser with 100 % coverage of the external surface of the riser. The paper presents the detailed characteristics of the first AURI prototype, describes its launching procedure and provides the preliminary test results from pool testing. The results showed that the AURI is a viable system for autonomous riser inspection. Offshore tests on riser pipelines are scheduled to be performed shortly.

  19. Jellyfish inspired underwater unmanned vehicle

    Science.gov (United States)

    Villanueva, Alex; Bresser, Scott; Chung, Sanghun; Tadesse, Yonas; Priya, Shashank

    2009-03-01

    An unmanned underwater vehicle (UUV) was designed inspired by the form and functionality of a Jellyfish. These natural organisms were chosen as bio-inspiration for a multitude of reasons including: efficiency of locomotion, lack of natural predators, proper form and shape to incorporate payload, and varying range of sizes. The structure consists of a hub body surrounded by bell segments and microcontroller based drive system. The locomotion of UUV was achieved by shape memory alloy "Biometal Fiber" actuation which possesses large strain and blocking force with adequate response time. The main criterion in design of UUV was the use of low-profile shape memory alloy actuators which act as artificial muscles. In this manuscript, we discuss the design of two Jellyfish prototypes and present experimental results illustrating the performance and power consumption.

  20. Active-imaging-based underwater navigation

    Science.gov (United States)

    Monnin, David; Schmitt, Gwenaël.; Fischer, Colin; Laurenzis, Martin; Christnacher, Frank

    2015-10-01

    Global navigation satellite systems (GNSS) are widely used for the localization and the navigation of unmanned and remotely operated vehicles (ROV). In contrast to ground or aerial vehicles, GNSS cannot be employed for autonomous underwater vehicles (AUV) without the use of a communication link to the water surface, since satellite signals cannot be received underwater. However, underwater autonomous navigation is still possible using self-localization methods which determines the relative location of an AUV with respect to a reference location using inertial measurement units (IMU), depth sensors and even sometimes radar or sonar imaging. As an alternative or a complementary solution to common underwater reckoning techniques, we present the first results of a feasibility study of an active-imaging-based localization method which uses a range-gated active-imaging system and can yield radiometric and odometric information even in turbid water.

  1. Sensor network architectures for monitoring underwater pipelines.

    Science.gov (United States)

    Mohamed, Nader; Jawhar, Imad; Al-Jaroodi, Jameela; Zhang, Liren

    2011-01-01

    This paper develops and compares different sensor network architecture designs that can be used for monitoring underwater pipeline infrastructures. These architectures are underwater wired sensor networks, underwater acoustic wireless sensor networks, RF (radio frequency) wireless sensor networks, integrated wired/acoustic wireless sensor networks, and integrated wired/RF wireless sensor networks. The paper also discusses the reliability challenges and enhancement approaches for these network architectures. The reliability evaluation, characteristics, advantages, and disadvantages among these architectures are discussed and compared. Three reliability factors are used for the discussion and comparison: the network connectivity, the continuity of power supply for the network, and the physical network security. In addition, the paper also develops and evaluates a hierarchical sensor network framework for underwater pipeline monitoring.

  2. Sensor Network Architectures for Monitoring Underwater Pipelines

    Directory of Open Access Journals (Sweden)

    Imad Jawhar

    2011-11-01

    Full Text Available This paper develops and compares different sensor network architecture designs that can be used for monitoring underwater pipeline infrastructures. These architectures are underwater wired sensor networks, underwater acoustic wireless sensor networks, RF (Radio Frequency wireless sensor networks, integrated wired/acoustic wireless sensor networks, and integrated wired/RF wireless sensor networks. The paper also discusses the reliability challenges and enhancement approaches for these network architectures. The reliability evaluation, characteristics, advantages, and disadvantages among these architectures are discussed and compared. Three reliability factors are used for the discussion and comparison: the network connectivity, the continuity of power supply for the network, and the physical network security. In addition, the paper also develops and evaluates a hierarchical sensor network framework for underwater pipeline monitoring.

  3. Time Synchronization for Mobile Underwater Sensor Networks

    Directory of Open Access Journals (Sweden)

    Ying Guo

    2013-01-01

    Full Text Available Time synchronization is very crucial for the implementation of energy constricted underwater wireless sensor networks (UWSN. The purpose of this paper is to present a time synchronization algorithm which is suitable to UWSN. Although several time synchronization protocols have been developed, most of them tend to break down when implemented on mobile underwater sensor networks. In this paper, we analyze the effect of node mobility, and propose a Mobile Counteracted Time Synchronization approach, called “Mc-Sync”, which is a novel time synchronization scheme for mobile underwater acoustic sensor networks. It makes use of two mobile reference nodes to counteract the effect of node mobility. We also analyze and design the optimized trajectories of the two mobile reference nodes in underwater environment. We show through analysis and simulation that Mc-Sync provides much better performance than existing schemes.

  4. Evolution: Fossil Ears and Underwater Sonar.

    Science.gov (United States)

    Lambert, Olivier

    2016-08-22

    A key innovation in the history of whales was the evolution of a sonar system together with high-frequency hearing. Fossils of an archaic toothed whale's inner ear bones provide clues for a stepwise emergence of underwater echolocation ability.

  5. Covert Underwater Communication with Marine Mammal Sounds

    NARCIS (Netherlands)

    Dol, H.S.; Quesson, B.A.J.; Benders, F.P.A.

    2008-01-01

    Acoustic underwater communication is essential for the participation of friendly submersible vehicles in netcentric operations. To prevent interception of exchanged information and, not less important, detection of the submersibles in a hostile environment, the communication should be sufficiently ‘

  6. Navigation System Fault Diagnosis for Underwater Vehicle

    DEFF Research Database (Denmark)

    Falkenberg, Thomas; Gregersen, Rene Tavs; Blanke, Mogens

    2014-01-01

    This paper demonstrates fault diagnosis on unmanned underwater vehicles (UUV) based on analysis of structure of the nonlinear dynamics. Residuals are generated using dierent approaches in structural analysis followed by statistical change detection. Hypothesis testing thresholds are made signal...

  7. Biomimetic synthesis for precursor of muscone

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Muscone is a precious fragrant compound scarce in nature. Many attempts have been made to synthesize this unique natural product. In this work, the one- carbon unit transfer reaction of tetrahydrofolate coenzyme was initiated. Benzimidazolium salt was used as the tetrahydrofolate coenzyme model at formic acid oxidation level and di-Grignard reagent as the nucleophile to which one-carbon unit was transferred; the biomimetic synthesis of 2,15- hexade-canedione, a precursor of muscone, was successfully accomplished by using the addition-hydrolysis reaction of benzimidazolium salt with Grignard reagent. And an impor-tant useful method for the synthesis of muscone is provided.

  8. Biotechnologies and biomimetics for civil engineering

    CERN Document Server

    Labrincha, J; Diamanti, M; Yu, C-P; Lee, H

    2015-01-01

    Putting forward an innovative approach to solving current technological problems faced by human society, this book encompasses a holistic way of perceiving the potential of natural systems. Nature has developed several materials and processes which both maintain an optimal performance and are also totally biodegradable, properties which can be used in civil engineering. Delivering the latest research findings to building industry professionals and other practitioners, as well as containing information useful to the public, ‘Biotechnologies and Biomimetics for Civil Engineering’ serves as an important tool to tackle the challenges of a more sustainable construction industry and the future of buildings.

  9. Tailored antireflective biomimetic nanostructures for UV applications

    Energy Technology Data Exchange (ETDEWEB)

    Morhard, Christoph; Pacholski, Claudia; Spatz, Joachim P [Department of New Materials and Biosystems, Max Planck Institute for Metals Research, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Lehr, Dennis; Brunner, Robert; Helgert, Michael [Carl Zeiss Jena GmbH, Technology Center, Carl-Zeiss-Promenade 10, D-07745 Jena (Germany); Sundermann, Michael, E-mail: Pacholski@mf.mpg.de [Carl Zeiss Jena GmbH, Technology Center, Carl-Zeiss-Strasse 56, D-73447 Oberkochen (Germany)

    2010-10-22

    Antireflective surfaces composed of biomimetic sub-wavelength structures that employ the 'moth eye principle' for reflectance reduction are highly desirable in many optical applications such as solar cells, photodetectors and laser optics. We report an efficient approach for the fabrication of antireflective surfaces based on a two-step process consisting of gold nanoparticle mask generation by micellar block copolymer nanolithography and a multi-step reactive ion etching process. Depending on the RIE process parameters nanostructured surfaces with tailored antireflective properties can easily be fabricated that show optimum performance for specific applications.

  10. Biomimetic magnetic nanocomposite for smart skins

    KAUST Repository

    Alfadhel, Ahmed

    2015-11-01

    We report a biomimetic tactile sensor consisting of magnetic nanocomposite artificial cilia and magnetic sensors. The nanocomposite is fashioned from polydimethylsiloxane and iron nanowires and exhibits a permanent magnetic behavior. This enables remote operation without an additional magnetic field to magnetize the nanowires, which simplifies device integration. Moreover, the highly elastic and easy patternable nanocomposite is corrosion resistant and thermally stable. The highly sensitive and power efficient tactile sensors can detect vertical and shear forces from interactions with objects. The sensors can operate in dry and wet environment with the ability to measure different properties such as the texture and the movement or stability of objects, with easily adjustable performance.

  11. Effect of urea on biomimetic aggregates

    Directory of Open Access Journals (Sweden)

    F.H. Florenzano

    1997-02-01

    Full Text Available The effect of urea on biomimetic aggregates (aqueous and reversed micelles, vesicles and monolayers was investigated to obtain insights into the effect of the denaturant on structured macromolecules. Direct evidence obtained from light scattering (static and dynamic, monolayer maximum isothermal compression and ionic conductivity measurements, together with indirect evidence from fluorescence photodissociation, fluorescence suppression, and thermal reactions, strongly indicates the direct interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied, which leads to an increase in the area per headgroup and also in the loss of counterion affinities

  12. Effect of urea on biomimetic aggregates.

    Science.gov (United States)

    Florenzano, F H; Politi, M J

    1997-02-01

    The effect of urea on biomimetic aggregates (aqueous and reversed micelles, vesicles and monolayers) was investigated to obtain insights into the effect of the denaturant on structured macromolecules. Direct evidence obtained from light scattering (static and dynamic), monolayer maximum isothermal compression and ionic conductivity measurements, together with indirect evidence from fluorescence photodissociation, fluorescence suppression, and thermal reactions, strongly indicates the direct interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied), which leads to an increase in the area per headgroup and also in the loss of counterion affinities. PMID:9239302

  13. Biomimetic surface modification of titanium surfaces for early cell capture by advanced electrospinning

    International Nuclear Information System (INIS)

    The time required for osseointegration with a metal implant having a smooth surface ranges from three to six months. We hypothesized that biomimetic coating surfaces with poly(lactic-co-glycolic acid) (PLGA)/collagen fibers and nano-hydroxyapatite (n-HA) on the implant would enhance the adhesion of mesenchymal stem cells. Therefore, this surface modification of dental and bone implants might enhance the process of osseointegration. In this study, we coated PLGA or PLGA/collagen (50:50 w/w ratio) fiber on Ti disks by modified electrospinning for 5 s to 2 min; after that, we further deposited n-HA on the fibers. PLGA fibers of fiber diameter 0.957 ± 0.357 µm had a contact angle of 9.9 ± 0.3° and PLGA/collagen fibers of fiber diameter 0.378 ± 0.068 µm had a contact angle of 0°. Upon n-HA incorporation, all the fibers had a contact angle of 0° owing to the hydrophilic nature of n-HA biomolecule. The cell attachment efficiency was tested on all the scaffolds for different intervals of time (10, 20, 30 and 60 min). The alkaline phosphatase activity, cell proliferation and mineralization were analyzed on all the implant surfaces on days 7, 14 and 21. Results of the cell adhesion study indicated that the cell adhesion was maximum on the implant surface coated with PLGA/collagen fibers deposited with n-HA compared to the other scaffolds. Within a short span of 60 min, 75% of the cells adhered onto the mineralized PLGA/collagen fibers. Similarly by day 21, the rate of cell proliferation was significantly higher (p ≤ 0.05) on the mineralized PLGA/collagen fibers owing to enhanced cell adhesion on these fibers. This enhanced initial cell adhesion favored higher cell proliferation, differentiation and mineralization on the implant surface coated with mineralized PLGA/collagen fibers.

  14. TRIDENT: A Framework for Autonomous Underwater Intervention

    OpenAIRE

    Sanz Valero, Pedro José; Ridao, Pere; Oliver, Gabriel; Melchiorri, Claudio; Casalino, Giuseppe; Silvestre, Carlos; Petillot, Yvan; Turetta, Alessio

    2011-01-01

    TRIDENT is a STREP project recently approved by the European Commission whose proposal was submitted to the ICT call 4 of the 7th Framework Program. The project proposes a new methodology for multipurpose underwater intervention tasks. To that end, a cooperative team formed with an Autonomous Surface Craft and an Intervention Autonomous Underwater Vehicle will be used. The proposed methodology splits the mission in two stages mainly devoted to survey and intervention tasks, res...

  15. Control of the MARES Autonomous Underwater Vehicle

    OpenAIRE

    Bruno Ferreira; Miguel Pinto; Anibal Matos; Nuno Cruz

    2009-01-01

    This paper focuses the control problem of a nonholonomic autonomous underwater vehicle, moving in the tridimensional space. The dynamic of a body in submarine environments is strongly nonlinear. This implies that classical linear controllers are often inadequate whereby Lyapunov theory is here considered. Methods based in this theory are promising tools to design controllers and are applied to the case of MARES, a small-sized autonomous underwater vehicle. Several controllers based only on Ly...

  16. Computer vision applied to underwater robotics

    OpenAIRE

    Pazzaglia, Fabio

    2016-01-01

    Ocean and seafloors are today probably the less known and unexplored places on earth.Nowadays, the continuous technological improvements on underwater inspection offer new challenges and possibilities. Beside the lassic acoustic sensors, modern cameras are playing an ever increasing role in autonomous underwater navigation. In particular, The capability to perform a context-driven navigation, based on what the vehicle is actually seeing on the seafloor, is of great interest in many research f...

  17. Adhesion and friction characteristics of carbon nanotube arrays

    International Nuclear Information System (INIS)

    There has been a great deal of interest in understanding, design and fabrication of bio-mimetic and bio-inspired adhesives in recent years. In this paper we present theoretical investigations on adhesion, friction behaviors and characteristics of fibrillar arrays composed of noninteracting carbon nanotubes for bio-inspired dry adhesives. Contact, compression, subsequent pulling off and dry sliding friction simulations were performed. It is demonstrated that there are two different adhesion forces during pull off. Static friction force values are in between 40 and 60 N cm−2 at different loads and they are significantly larger than the normal adhesion forces. Dynamic friction force and load are anisotropic and they depend on the direction of the motion. It is also found that friction force values and friction coefficients decrease although contact length and contact area increase when the loads are high. This is due to the arms of the nanotubes which bend significantly and act as stiffer springs at high loads. (paper)

  18. Nanoscale friction and adhesion of tree frog toe pads.

    Science.gov (United States)

    Kappl, Michael; Kaveh, Farzaneh; Barnes, W Jon P

    2016-01-01

    Tree frogs have become an object of interest in biomimetics due to their ability to cling to wet and slippery surfaces. In this study, we have investigated the adhesion and friction behavior of toe pads of White's tree frog (Litoria caerulea) using atomic force microscopy (AFM) in an aqueous medium. Facilitating special types of AFM probes with radii of ∼400 nm and ∼13 μm, we were able to sense the frictional response without damaging the delicate nanopillar structures of the epithelial cells. While we observed no significant adhesion between both types of probes and toe pads in wet conditions, frictional forces under such conditions were very pronounced and friction coefficients amounted between 0.3 and 1.1 for the sliding friction between probes and the epithelial cell surfaces. PMID:27165465

  19. Preparation of biomimetic nano-structured films with multi-scale roughness

    Science.gov (United States)

    Shelemin, A.; Nikitin, D.; Choukourov, A.; Kylián, O.; Kousal, J.; Khalakhan, I.; Melnichuk, I.; Slavínská, D.; Biederman, H.

    2016-06-01

    Biomimetic nano-structured films are valuable materials in various applications. In this study we introduce a fully vacuum-based approach for fabrication of such films. The method combines deposition of nanoparticles (NPs) by gas aggregation source and deposition of overcoat thin film that fixes the nanoparticles on a surface. This leads to the formation of nanorough surfaces which, depending on the chemical nature of the overcoat, may range from superhydrophilic to superhydrophobic. In addition, it is shown that by proper adjustment of the amount of NPs it is possible to tailor adhesive force on superhydrophobic surfaces. Finally, the possibility to produce NPs in a wide range of their size (45–240 nm in this study) makes it possible to produce surfaces not only with single scale roughness, but also with bi-modal or even multi-modal character. Such surfaces were found to be superhydrophobic with negligible water contact angle hysteresis and hence truly slippery.

  20. Development of ICPF Actuated Underwater Microrobots

    Institute of Scientific and Technical Information of China (English)

    Xiuo-Fen Ye; Bao-Feng Gao; Shu-Xiang Guo; Li-Quan Wang

    2006-01-01

    It is our target to develop underwater microrobots for medical and industrial applications. This kind of underwater microrobots should have the characteristics of flexibility, good response and safety. Its structure should be simple and it can be driven by low voltage and produces no pollution or noise. The low actuating voltage and quick bending responses of Ionic Conducting Polymer Film (ICPF) are considered very useful and attractive for constructing various types of actuators and sensors. In this paper, we will first study the characteristics of the ICPF actuator used in underwater microrobot to realize swimming and walking. Then, we propose a new prototype model of underwater swimming microrobot utilizing only one piece of ICPF as the servo actuator. Through theoretic analysis, the motion mechanism of the microrobot is illustrated. It can swim forward and vertically. The relationships between moving speed and signal voltage amplitude and signal frequency is obtained after experimental study. Lastly, we present a novel underwater crab-like walking microrobot named crabliker-1. It has eight legs, and each leg is made up of two pieces of ICPF. Three sample processes of the octopod gait are proposed with a new analyzing method. The experimental results indicate that the crab-like underwater microrobot can perform transverse and rotation movement when the legs of the crab collaborate.

  1. Affordable underwater wireless optical communication using LEDs

    Science.gov (United States)

    Pilipenko, Vladimir; Arnon, Shlomi

    2013-09-01

    In recent years the need for high data rate underwater wireless communication (WC) has increased. Nowadays, the conventional technology for underwater communication is acoustic. However, the maximum data rate that acoustic technology can provide is a few kilobits per second. On the other hand, emerging applications such as underwater imaging, networks of sensors and swarms of underwater vehicles require much faster data rates. As a result, underwater optical WC, which can provide much higher data rates, has been proposed as an alternative means of communication. In addition to high data rates, affordable communication systems become an important feature in the development requirements. The outcome of these requirements is a new system design based on off-the-shelf components such as blue and green light emitting diodes (LEDs). This is due to the fact that LEDs offer solutions characterized by low cost, high efficiency, reliability and compactness. However, there are some challenges to be met when incorporating LEDs as part of the optical transmitter, such as low modulation rates and non linearity. In this paper, we review the main challenges facing the incorporation of LEDs as an integral part of underwater WC systems and propose some techniques to mitigate the LED limitations in order to achieve high data rate communication

  2. An underwater optical wireless communication network

    Science.gov (United States)

    Arnon, Shlomi

    2009-08-01

    The growing need for underwater observation and sub-sea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, bio-geochemical, evolutionary and ecological changes in the sea, ocean and lake environments and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. We present models of three kinds of optical wireless communication links a) a line-of-sight link, b) a modulating retro-reflector link and c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered lighted it was possible to mitigate this decrease in some cases. We conclude from the analysis that a high data rate underwater optical wireless network is a feasible solution for emerging applications such as UUV to UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.

  3. Non-uniform breaking of molecular bonds, peripheral morphology and releasable adhesion by elastic anisotropy in bio-adhesive contacts.

    Science.gov (United States)

    Liu, Yan; Gao, Yanfei

    2015-01-01

    Biological adhesive contacts are usually of hierarchical structures, such as the clustering of hundreds of sub-micrometre spatulae on keratinous hairs of gecko feet, or the clustering of molecular bonds into focal contacts in cell adhesion. When separating these interfaces, releasable adhesion can be accomplished by asymmetric alignment of the lowest scale discrete bonds (such as the inclined spatula that leads to different peeling force when loading in different directions) or by elastic anisotropy. However, only two-dimensional contact has been analysed for the latter method (Chen & Gao 2007 J. Mech. Phys. Solids 55, 1001-1015 (doi:10.1016/j.jmps.2006.10.008)). Important questions such as the three-dimensional contact morphology, the maximum to minimum pull-off force ratio and the tunability of releasable adhesion cannot be answered. In this work, we developed a three-dimensional cohesive interface model with fictitious viscosity that is capable of simulating the de-adhesion instability and the peripheral morphology before and after the onset of instability. The two-dimensional prediction is found to significantly overestimate the maximum to minimum pull-off force ratio. Based on an interface fracture mechanics analysis, we conclude that (i) the maximum and minimum pull-off forces correspond to the largest and smallest contact stiffness, i.e. 'stiff-adhere and compliant-release', (ii) the fracture toughness is sensitive to the crack morphology and the initial contact shape can be designed to attain a significantly higher maximum-to-minimum pull-off force ratio than a circular contact, and (iii) since the adhesion is accomplished by clustering of discrete bonds or called bridged crack in terms of fracture mechanics terminology, the above conclusions can only be achieved when the bridging zone is significantly smaller than the contact size. This adhesion-fracture analogy study leads to mechanistic predictions that can be readily used to design biomimetics and

  4. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  5. Evaluation in vitro and in vivo of biomimetic hydroxyapatite coated on titanium dental implants

    International Nuclear Information System (INIS)

    Among several materials used as dental implants, metals present relatively high tensile strengths. Although metals are biotolerable, they do not adhere to bone tissues. On the other hand, bioactive ceramics are known to chemically bind to bone tissues, but they are not enough mechanically resistant to tension stresses. To overcome this drawback, biotolerable metals can be coated with bioactive ceramics. Various methods can be employed for coating ceramic layers on metal substrates, among them ion sputtering, plasma spray, sol-gel, electrodeposition and a biomimetic process [E.C.S. Rigo, L.C. Oliveira, L.A. Santos, A.O. Boschi, R.G. Carrodeguas. Implantes metalicos recobertos com hidroxiapatita. Revista de Engenharia Biomedica, vol. 15 (1999), numeros 1-2, 21-29. Rio de Janeiro]. The aim of this work was to study the effect of the substitution of G glass, employed in the conventional biomimetic method during the nucleation stage, by a solution of sodium silicate (SS) on the chemical and morphological characteristics, and the adhesion of biomimetic coatings deposited on Ti implants. The obtained coatings were analyzed by diffuse reflectance FTIR spectroscopy (DRIFT) and scanning electron microscopy (SEM). Titanium implants were immersed in synthetic body fluid (SBF) and SS. All implants were left inside an incubator at 37 deg. C for 7 days, followed by immersion in 1.5 SBF and taken back to the incubator for additional 6 days at 37 deg. C. The 1.5 SBF were refreshed every 2 days. At the end of the treatment, the implants were washed in distilled and deionized water and dried at room temperature. To check the osseointegration, titanium implants coated with biomimetic method were inserted in rabbit's tibia, remaining there for 8 weeks. During the healing period, polyfluorochrome sequential labeling was inoculated in the rabbits to determine the period of bone remodeling. Results from DRIFT and SEM showed that, for all processing variants employed, a HA coating was

  6. Biomimetic High-Density Lipoproteins from a Gold Nanoparticle Template

    Science.gov (United States)

    Luthi, Andrea Jane

    For hundreds of years the field of chemistry has looked to nature for inspiration and insight to develop novel solutions for the treatment of human diseases. The ability of chemists to identify, mimic, and modifiy small molecules found in nature has led to the discovery and development of many important therapeutics. Chemistry on the nanoscale has made it possible to mimic natural, macromolecular structures that may also be useful for understanding and treating diseases. One example of such a structure is high-density lipoprotein (HDL). The goal of this work is to use a gold nanoparticle (Au NP) as a template to synthesize functional mimics of HDL and characterize their structure and function. Chapter 1 details the structure and function of natural HDL and how chemistry on the nanoscale provides new strategies for mimicking HDL. This Chapter also describes the first examples of using nanoparticles to mimic HDL. Chapter 2 reports the synthesis and characterization of biomimetic HDL using different sizes of Au NPs and different surface chemistries and how these variables can be used to tailor the properties of biomimetic HDL. From these studies the optimal strategy for synthesizing biomimetic HDL was determined. In Chapter 3, the optimization of the synthesis of biomimetic HDL is discussed as well as a full characterization of its structure. In addition, the work in this chapter shows that biomimetic HDL can be synthesized on a large scale without alterations to its structure or function. Chapter 4 focuses on understanding the pathways by which biomimetic HDL accepts cholesterol from macrophage cells. The results of these studies demonstrate that biomimetic HDL is able to accept cholesterol by both active and passive pathways of cholesterol efflux. In Chapter 5 the preliminary results of in vivo studies to characterize the pharmacokinetics and pharmacodynamics of biomimetic HDL are presented. These studies suggest that biomimetic HDL traffics through tissues prone to

  7. Effect of Microscale Contact State of Polyurethane Surface on Adhesion and Friction

    Institute of Scientific and Technical Information of China (English)

    Yu Min; Ji Ai-hong; Dai Zhen-dong

    2006-01-01

    The effect of microscale contact of rough surfaces on the adhesion and friction under negative normal forces was experimentally investigated. The adhesive force of single point contact - sapphire ball to flat polyurethane did not vary with the normal force. With rough surface contact, which was assumed to be a great number of point contacts, the adhesive force increased logarithmically with the normal force. Under negative normal force adhesive state, the tangential force (more than hundred mN)were much larger than the negative normal force (several mN) and increased with the linear decrease of negative normal force.The results reveal why the gecko's toe must slide slightly on the target surface when it makes contact on a surface and suggest how a biomimetic gecko foot might be designed.

  8. Biomimetics as a design methodology – possibilities and challenges

    DEFF Research Database (Denmark)

    Lenau, Torben Anker

    2009-01-01

    Biomimetics – or bionik as it is called in parts of Europe – offer a number of promising opportunities and challenges for the designer. The paper investigates how biomimetics as a design methodology is used in engineering design by looking at examples of biological searches and highlight...... the possibilities and challenges. Biomimetics for engineering design is explored through an experiment involving 12 design engineering students. For 7 selected problem areas they searched biology literature available at a university library and identified a number of biological solutions. Central solution...

  9. Biomimetics applied to centering in micro-assembly

    DEFF Research Database (Denmark)

    Shu, L.H.; Lenau, Torben Anker; Hansen, Hans Nørgaard;

    2003-01-01

    This paper describes the application of a biomimetic search method to develop ideas for centering objects in micro-assembly. Biomimetics involves the imitation of biological phenomena to solve problems. An obstacle to the use of biomimetics in engineering is knowledge of biological phenomena...... that is relevant to the problem at hand. The method described here starts with an engineering problem, and then systematically searches for analogous biological phenomena using functional keywords. This method is illustrated by finding and using analogies for the problem of positioning and centering objects during...

  10. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    that imposes selection pressure for resistant bacteria. New approaches are urgently needed. Targeting bacterial virulence functions directly is an attractive alternative. An obvious target is bacterial adhesion. Bacterial adhesion to surfaces is the first step in colonization, invasion, and biofilm formation....... As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  11. Particle adhesion and removal

    CERN Document Server

    Mittal, K L

    2015-01-01

    The book provides a comprehensive and easily accessible reference source covering all important aspects of particle adhesion and removal.  The core objective is to cover both fundamental and applied aspects of particle adhesion and removal with emphasis on recent developments.  Among the topics to be covered include: 1. Fundamentals of surface forces in particle adhesion and removal.2. Mechanisms of particle adhesion and removal.3. Experimental methods (e.g. AFM, SFA,SFM,IFM, etc.) to understand  particle-particle and particle-substrate interactions.4. Mechanics of adhesion of micro- and  n

  12. Halogenated DOPA in a Marine Adhesive Protein.

    Science.gov (United States)

    Sun, Cheng Jun; Srivastava, Aasheesh; Reifert, Jack R; Waite, J Herbert

    2009-02-01

    The sandcastle worm Phragmatopoma californica, a marine polychaete, constructs a tube-like shelter by cementing together sand grains using a glue secreted from the building organ in its thorax. The glue is a mixture of post-translationally modified proteins, notably the cement proteins Pc-1 and Pc-2 with the amino acid, 3,4-dihydroxyphenyl-L-alanine (DOPA). Significant amounts of a halogenated derivative of DOPA were isolated from the worm cement following partial acid hydrolysis and capture of catecholic amino acids by phenylboronate affinity chromatography. Analysis by tandem mass spectrometry and (1)H NMR indicates the DOPA derivative to be 2-chloro-4, 5-dihydroxyphenyl-L-alanine. The potential roles of 2-chloro-DOPA in chemical defense and underwater adhesion are considered.

  13. Advanced Concepts for Underwater Acoustic Channel Modeling

    Science.gov (United States)

    Etter, P. C.; Haas, C. H.; Ramani, D. V.

    2014-12-01

    This paper examines nearshore underwater-acoustic channel modeling concepts and compares channel-state information requirements against existing modeling capabilities. This process defines a subset of candidate acoustic models suitable for simulating signal propagation in underwater communications. Underwater-acoustic communications find many practical applications in coastal oceanography, and networking is the enabling technology for these applications. Such networks can be formed by establishing two-way acoustic links between autonomous underwater vehicles and moored oceanographic sensors. These networks can be connected to a surface unit for further data transfer to ships, satellites, or shore stations via a radio-frequency link. This configuration establishes an interactive environment in which researchers can extract real-time data from multiple, but distant, underwater instruments. After evaluating the obtained data, control messages can be sent back to individual instruments to adapt the networks to changing situations. Underwater networks can also be used to increase the operating ranges of autonomous underwater vehicles by hopping the control and data messages through networks that cover large areas. A model of the ocean medium between acoustic sources and receivers is called a channel model. In an oceanic channel, characteristics of the acoustic signals change as they travel from transmitters to receivers. These characteristics depend upon the acoustic frequency, the distances between sources and receivers, the paths followed by the signals, and the prevailing ocean environment in the vicinity of the paths. Properties of the received signals can be derived from those of the transmitted signals using these channel models. This study concludes that ray-theory models are best suited to the simulation of acoustic signal propagation in oceanic channels and identifies 33 such models that are eligible candidates.

  14. Geometric documentation of underwater archaeological sites

    Directory of Open Access Journals (Sweden)

    Eleni Diamanti

    2013-12-01

    Full Text Available Photogrammetry has often been the most preferable method for the geometric documentation of monuments, especially in cases of highly complex objects, of high accuracy and quality requirements and, of course, budget, time or accessibility limitations. Such limitations, requirements and complexities are undoubtedly features of the highly challenging task of surveying an underwater archaeological site. This paper is focused on the case of a Hellenistic shipwreck found in Greece at the Southern Euboean gulf, 40-47 meters below the sea surface. Underwater photogrammetry was chosen as the ideal solution for the detailed and accurate mapping of a shipwreck located in an environment with limited accessibility. There are time limitations when diving at these depths so it is essential that the data collection time is kept as short as possible. This makes custom surveying techniques rather impossible to apply. However, with the growing use of consumer cameras and photogrammetric software, this application is becoming easier, thus benefiting a wide variety of underwater sites. Utilizing cameras for underwater photogrammetry though, poses some crucial modeling problems, due to the refraction effect and further additional parameters which have to be co-estimated [1]. The applied method involved an underwater calibration of the camera as well as conventional field survey measurements in order to establish a reference frame. The application of a three-dimensional trilateration using common tape measures was chosen for this reason. Among the software that was used for surveying and photogrammetry processing, were Site Recorder SE, Eos Systems Photomodeler, ZI’s SSK and Rhinoceros. The underwater archaeological research at the Southern Euboean gulf is a continuing project carried out by the Hellenic Institute for Marine Archaeology (H.I.M.A. in collaboration with the Greek Ephorate of Underwater Antiquities, under the direction of the archaeologist G

  15. Investigation of Thunniform Swimming Using Material Testing, Biomimetic Robotics and Particle Image Velocimetry

    Science.gov (United States)

    Zhu, Ruijie; Saraiya, Vishaal; Zhu, Jianzhong; Lewis, Gregory; Bart-Smith, Hilary

    2015-11-01

    Thunniform swimming is well recognized as an efficient method for high-speed long-distance underwater travelers such as tuna. Previous research has shown that tuna relies on contraction and relaxation of red muscle to generate angular motion of its large, crescent-shaped caudal fin through its peduncle. However, few researchers conduct deep investigation of material properties of tuna caudal fin and peduncle. This research project is composed of two parts, first of which is determining mechanical properties of components such as spine joints, tendons, fin rays and cartilage, from which the biomechanics of tuna tail can be better understood. The second part is building a robotic system mimicking a real tuna tail based on previously retrieved information, and testing the system inside a flow tank. With the help of PIV (Particle Image Velocimetry), fluid-structure interaction of the biomimetic fin is visualized and data such as swimming speed and power consumption are retrieved through the robotic system. The final outcome should explain how the material properties of tuna tail affect fluid dynamics of thunniform swimming. This project is supported by Office of Naval Research (ONRBAA13-022).

  16. Biomimetics materials, structures and processes : examples, ideas and case studies

    CERN Document Server

    Bruckner, Dietmar; Hellmich, Christian; Schmiedmayer, Heinz-Bodo; Stachelberger, Herbert; Gebeshuber, Ille

    2011-01-01

    The book presents an outline of current activities in the field of biomimetics and integrates a variety of applications comprising biophysics, surface sciences, architecture and medicine. Biomimetics as innovation method is characterised by interdisciplinary information transfer from the life sciences to technical application fields aiming at increased performance, functionality and energy efficiency. The contributions of the book relate to the research areas: - Materials and structures in nanotechnology and biomaterials - Biomimetic approaches to develop new forms, construction principles and design methods in architecture - Information and dynamics in automation, neuroinformatics and biomechanics Readers will be informed about the latest research approaches and results in biomimetics with examples ranging from bionic nano-membranes to function-targeted design of tribological surfaces and the translation of natural auditory coding strategies.

  17. A review paper on biomimetic calcium phosphate coatings

    OpenAIRE

    Lin, X.; De Groot,, P.A.J.; Wang, D.; Hu, Q; Wismeijer, D.; Liu, Y

    2015-01-01

    Biomimetic calcium phosphate coatings have been developed for bone regeneration and repair because of their biocompatibility, osteoconductivity, and easy preparation. They can be rendered osteoinductive by incorporating an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2), into the crystalline lattice work in physiological situations. The biomimetic calcium phosphate coating enables a controlled, slow and local release of BMP-2 when it undergoes cell mediated coating degradation ...

  18. Effective Length Design of Humanoid Robot Fingers Using Biomimetic Optimization

    OpenAIRE

    Byoung-Ho Kim

    2015-01-01

    In this study, we propose an effective design method for the phalangeal parameters and the total size of humanoid robot fingers based on a biomimetic optimization. For the optimization, an interphalangeal joint coordination parameter and the length constraints inherent in human fingers are considered from a biomimetic perspective. A reasonable grasp formulation is also taken into account from the viewpoint of power grasping, where the grasp space of a humanoid robot finger is importantly cons...

  19. Aloe vera Induced Biomimetic Assemblage of Nucleobase into Nanosized Particles

    OpenAIRE

    Chauhan, Arun; Zubair, Swaleha; Sherwani, Asif; Owais, Mohammad

    2012-01-01

    Aim Biomimetic nano-assembly formation offers a convenient and bio friendly approach to fabricate complex structures from simple components with sub-nanometer precision. Recently, biomimetic (employing microorganism/plants) synthesis of metal and inorganic materials nano-particles has emerged as a simple and viable strategy. In the present study, we have extended biological synthesis of nano-particles to organic molecules, namely the anticancer agent 5-fluorouracil (5-FU), using Aloe vera lea...

  20. Underwater blast injury: a review of standards.

    Science.gov (United States)

    Lance, Rachel M; Bass, Cameron R

    2015-09-01

    The first cases of underwater blast injury appeared in the scientific literature in 1917, and thousands of service members and civilians were injured or killed by underwater blast during WWII. The prevalence of underwater blast injuries and occupational blasting needs led to the development of many safety standards to prevent injury or death. Most of these standards were not supported by experimental data or testing. In this review, we describe existing standards, discuss their origins, and we comprehensively compare their prescriptions across standards. Surprisingly, we found that most safety standards had little or no scientific basis, and prescriptions across standards often varied by at least an order of magnitude. Many published standards traced back to a US Navy 500 psi guideline, which was intended to provide a peak pressure at which injuries were likely to occur. This standard itself seems to have been based upon a completely unfounded assertion that has propagated throughout the literature in subsequent years. Based on the limitations of the standards discussed, we outline future directions for underwater blast injury research, such as the compilation of epidemiological data to examine actual injury risk by human beings subjected to underwater blasts. PMID:26415071

  1. Omnidirectional Underwater Camera Design and Calibration

    Directory of Open Access Journals (Sweden)

    Josep Bosch

    2015-03-01

    Full Text Available This paper presents the development of an underwater omnidirectional multi-camera system (OMS based on a commercially available six-camera system, originally designed for land applications. A full calibration method is presented for the estimation of both the intrinsic and extrinsic parameters, which is able to cope with wide-angle lenses and non-overlapping cameras simultaneously. This method is valid for any OMS in both land or water applications. For underwater use, a customized housing is required, which often leads to strong image distortion due to refraction among the different media. This phenomena makes the basic pinhole camera model invalid for underwater cameras, especially when using wide-angle lenses, and requires the explicit modeling of the individual optical rays. To address this problem, a ray tracing approach has been adopted to create a field-of-view (FOV simulator for underwater cameras. The simulator allows for the testing of different housing geometries and optics for the cameras to ensure a complete hemisphere coverage in underwater operation. This paper describes the design and testing of a compact custom housing for a commercial off-the-shelf OMS camera (Ladybug 3 and presents the first results of its use. A proposed three-stage calibration process allows for the estimation of all of the relevant camera parameters. Experimental results are presented, which illustrate the performance of the calibration method and validate the approach.

  2. Arrival-based equalizer for underwater communication systems

    OpenAIRE

    Ijaz, S.; Silva, A.; Jesus, S.M.

    2012-01-01

    One of the challenges in the present underwater acoustic communication systems is to combat the underwater channel effects which results in time and frequency spreading of the transmitted signal. The time spreading is caused by the multipath effect while the frequency spreading is due to the time variability of the underwater channel. The passive Time Reversal (pTR) equalizer has been used in underwater communications because of its time focusing property which minimizes the time spread...

  3. Feasibility of underwater free space quantum key distribution

    CERN Document Server

    Shi, Peng; Li, Wen-Dong; Gu, Yong-Jian

    2014-01-01

    We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we calculate the bit rate, the fidelity, and the quantum bit error rate of photons when transmitting underwater. It can be observed from our simulations that maximally secure single photon underwater BB84 QKD is feasible with a distance of about 125m in the clearest ocean water.

  4. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks †

    OpenAIRE

    Qiu Wang; Hong-Ning Dai; Xuran Li; Hao Wang; Hong Xiao

    2016-01-01

    The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones ...

  5. Intelligent Navigation for a Solar Powered Unmanned Underwater Vehicle

    OpenAIRE

    Francisco García-Córdova; Antonio Guerrero-González

    2013-01-01

    In this paper, an intelligent navigation system for an unmanned underwater vehicle powered by renewable energy and designed for shadow water inspection in missions of a long duration is proposed. The system is composed of an underwater vehicle, which tows a surface vehicle. The surface vehicle is a small boat with photovoltaic panels, a methanol fuel cell and communication equipment, which provides energy and communication to the underwater vehicle. The underwater v...

  6. Fish and chips: implementation of a neural network model into computer chips to maximize swimming efficiency in autonomous underwater vehicles.

    Science.gov (United States)

    Blake, R W; Ng, H; Chan, K H S; Li, J

    2008-09-01

    Recent developments in the design and propulsion of biomimetic autonomous underwater vehicles (AUVs) have focused on boxfish as models (e.g. Deng and Avadhanula 2005 Biomimetic micro underwater vehicle with oscillating fin propulsion: system design and force measurement Proc. 2005 IEEE Int. Conf. Robot. Auto. (Barcelona, Spain) pp 3312-7). Whilst such vehicles have many potential advantages in operating in complex environments (e.g. high manoeuvrability and stability), limited battery life and payload capacity are likely functional disadvantages. Boxfish employ undulatory median and paired fins during routine swimming which are characterized by high hydromechanical Froude efficiencies (approximately 0.9) at low forward speeds. Current boxfish-inspired vehicles are propelled by a low aspect ratio, 'plate-like' caudal fin (ostraciiform tail) which can be shown to operate at a relatively low maximum Froude efficiency (approximately 0.5) and is mainly employed as a rudder for steering and in rapid swimming bouts (e.g. escape responses). Given this and the fact that bioinspired engineering designs are not obligated to wholly duplicate a biological model, computer chips were developed using a multilayer perception neural network model of undulatory fin propulsion in the knifefish Xenomystus nigri that would potentially allow an AUV to achieve high optimum values of propulsive efficiency at any given forward velocity, giving a minimum energy drain on the battery. We envisage that externally monitored information on flow velocity (sensory system) would be conveyed to the chips residing in the vehicle's control unit, which in turn would signal the locomotor unit to adopt kinematics (e.g. fin frequency, amplitude) associated with optimal propulsion efficiency. Power savings could protract vehicle operational life and/or provide more power to other functions (e.g. communications).

  7. Fish and chips: implementation of a neural network model into computer chips to maximize swimming efficiency in autonomous underwater vehicles.

    Science.gov (United States)

    Blake, R W; Ng, H; Chan, K H S; Li, J

    2008-09-01

    Recent developments in the design and propulsion of biomimetic autonomous underwater vehicles (AUVs) have focused on boxfish as models (e.g. Deng and Avadhanula 2005 Biomimetic micro underwater vehicle with oscillating fin propulsion: system design and force measurement Proc. 2005 IEEE Int. Conf. Robot. Auto. (Barcelona, Spain) pp 3312-7). Whilst such vehicles have many potential advantages in operating in complex environments (e.g. high manoeuvrability and stability), limited battery life and payload capacity are likely functional disadvantages. Boxfish employ undulatory median and paired fins during routine swimming which are characterized by high hydromechanical Froude efficiencies (approximately 0.9) at low forward speeds. Current boxfish-inspired vehicles are propelled by a low aspect ratio, 'plate-like' caudal fin (ostraciiform tail) which can be shown to operate at a relatively low maximum Froude efficiency (approximately 0.5) and is mainly employed as a rudder for steering and in rapid swimming bouts (e.g. escape responses). Given this and the fact that bioinspired engineering designs are not obligated to wholly duplicate a biological model, computer chips were developed using a multilayer perception neural network model of undulatory fin propulsion in the knifefish Xenomystus nigri that would potentially allow an AUV to achieve high optimum values of propulsive efficiency at any given forward velocity, giving a minimum energy drain on the battery. We envisage that externally monitored information on flow velocity (sensory system) would be conveyed to the chips residing in the vehicle's control unit, which in turn would signal the locomotor unit to adopt kinematics (e.g. fin frequency, amplitude) associated with optimal propulsion efficiency. Power savings could protract vehicle operational life and/or provide more power to other functions (e.g. communications). PMID:18626130

  8. Biomimetic mineral coatings in dental and orthopaedic implantology

    Institute of Scientific and Technical Information of China (English)

    Yue-lian LIU; Klaas de GROOT; Ernst B.HUNZIKER

    2009-01-01

    Biomimetic techniques are used to deposit coatings of calcium phosphate upon medical devices. The procedure is conducted under near-physiological, or "biomimetic", conditions of temperature and pH primarily to improve their biocompatibility and biodegradability of the materials. The inorganic layers genelated by biomi-metic methods resemble bone mineral, and can be degraded within a biological milieu.The biomimetic coating technique involves the nuclea-tion and growth of bone-like crystals upon a pretreated substrate by immersing this in a supersaturated solution of calcium phosphate under physiological conditions of temperature (37~C) and pH (7.4). The method, originally developed by Kokubo in 1990, has since undergone improvement and refinement by several groups of investigators.Biomimetic coatings are valuable in that they can serve as a vehicle for the slow and sustained release of osteogenic agents at the site of implantation. This attribute is rendered possible by the near-physiological conditions under which these coatings are prepared, which permits an incorporation of binactive agents into the inorganic crystal latticework rather than their nlere superficial adsorption onto preformed layers. In addition, the biomimetic coating technique can be applied to implants of an organic as well as of an inorganic nature and to those with irregular surface geometries, which is not possible using conventional methodologies.

  9. Sensing in nature: using biomimetics for design of sensors

    DEFF Research Database (Denmark)

    Lenau, Torben Anker; Cheong, Hyunmin; Shu, Li

    2010-01-01

    The paper illustrates how biomimetics can be applied in sensor design. Biomimetics is an engineering discipline that uses nature as an inspiration source for generating ideas for how to solve engineering problems. Using biomimetics involves a search for relevant cases, a proper analysis of the bi......The paper illustrates how biomimetics can be applied in sensor design. Biomimetics is an engineering discipline that uses nature as an inspiration source for generating ideas for how to solve engineering problems. Using biomimetics involves a search for relevant cases, a proper analysis...... of the biological solutions, identification of design principles and design of the desired artefact. We use a search method developed at University of Toronto. It is based on formulation of relevant keywords and search for occurrences in a standard university biology textbook. Most often a simple formulation...... of keywords and a following search is not enough to generate a sufficient amount of useful ideas or the search gives to many results. This is handled by a more advanced search strategy where the search is either widened or it is focused further mainly using biological synonyms. The paper also reviews a number...

  10. AUV Control and Communication using Underwater Acoustic Networks

    OpenAIRE

    Marques, Eduardo R.B.; Pinto, Marques; Kragelund, Sean; Dias, Paulo S.; Madureira, Luis; Sousa, Alexandre; Correia, Marcio; Ferreira, Hugo; Goncalves, Rui; Martins, Richardo; Horner, Douglas P.; Healey, Anthony J.; Goncalves, Gil M.; Sousa, Joao B.

    2007-01-01

    Underwater acoustic networks can be quite effective to establish communication links between autonomous underwater vehicles (AUVs) and other vehicles or control units, enabling complex vehicle applications and control scenarios. A communications and control framework to support the use of underwater acoustic networks and sample application scenarios are described for single and multi-AUV operation.

  11. Centralised versus Decentralised Control Reconfiguration for Collaborating Underwater Robots

    DEFF Research Database (Denmark)

    Furno, Lidia; Nielsen, Mikkel Cornelius; Blanke, Mogens

    2015-01-01

    The present paper introduces an approach to fault-tolerant reconfiguration for collaborating underwater robots. Fault-tolerant reconfiguration is obtained using the virtual actuator approach, Steen (2005). The paper investigates properties of a centralised versus a decentralised implementation...... an underwater drill needs to be transported and positioned by three collaborating robots as part of an underwater autonomous operation....

  12. Underwater robots to safeguard Olympic Games in 2008

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ A small-sized autonomous underwater vehicle(AUV) independently developed and built by CAS researchers has been designated as an underwater guard for the forthcoming Olympic Game in 2008 in Beijing. It has recently been approved by the Olympic Sub-committee of Sailing to be a component of the "underwater safety alert system" of the competition.

  13. Clues for biomimetics from natural composite materials

    Science.gov (United States)

    Lapidot, Shaul; Meirovitch, Sigal; Sharon, Sigal; Heyman, Arnon; Kaplan, David L; Shoseyov, Oded

    2013-01-01

    Bio-inspired material systems are derived from different living organisms such as plants, arthropods, mammals and marine organisms. These biomaterial systems from nature are always present in the form of composites, with molecular-scale interactions optimized to direct functional features. With interest in replacing synthetic materials with natural materials due to biocompatibility, sustainability and green chemistry issues, it is important to understand the molecular structure and chemistry of the raw component materials to also learn from their natural engineering, interfaces and interactions leading to durable and highly functional material architectures. This review will focus on applications of biomaterials in single material forms, as well as biomimetic composites inspired by natural organizational features. Examples of different natural composite systems will be described, followed by implementation of the principles underlying their composite organization into artificial bio-inspired systems for materials with new functional features for future medicine. PMID:22994958

  14. Biomimetic electrospun nanofibers for tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Susan; Li Bojun; Ma Zuwei; Wei He; Chan Casey; Ramakrishna, Seeram [Nanoscience and Nanotechnology Initiative (NUSNNI), Faculty of Engineering, National University of Singapore, 117576 Singapore (Singapore)

    2006-09-15

    Nanofibers exist widely in human tissue with different patterns. Electrospinning nanotechnology has recently gained a new impetus due to the introduction of the concept of biomimetic nanofibers for tissue regeneration. The advanced electrospinning technique is a promising method to fabricate a controllable continuous nanofiber scaffold similar to the natural extracellular matrix. Thus, the biomedical field has become a significant possible application field of electrospun fibers. Although electrospinning has developed rapidly over the past few years, electrospun nanofibers are still at a premature research stage. Further comprehensive and deep studies on electrospun nanofibers are essential for promoting their biomedical applications. Current electrospun fiber materials include natural polymers, synthetic polymers and inorganic substances. This review briefly describes several typically electrospun nanofiber materials or composites that have great potential for tissue regeneration, and describes their fabrication, advantages, drawbacks and future prospects. (topical review)

  15. Progress of Biomimetic Artificial Nose and Tongue

    Science.gov (United States)

    Wang, Ping; Liu, Qingjun

    2009-05-01

    As two of the basic senses of human beings, olfaction and gustation play a very important role in daily life. These two types of chemical sensors are important for recognizing environmental conditions. Electronic nose and electronic tongue, which mimics animals' olfaction and gustation to detect odors and chemical components, have been carried out due to their potential commercial applications for biomedicine, food industry and environmental protection. In this report, the biomimetic artificial nose and tongue is presented. Firstly, the smell and taste sensors mimicking the mammalian olfaction and gustation was described, and then, some mimetic design of electronic nose and tongue for odorants and tastants detection are developed. Finally, olfactory and gustatory biosensors are presented as the developing trends of this field.

  16. Biomimetic Hybrid Nanocontainers with Selective Permeability.

    Science.gov (United States)

    Messager, Lea; Burns, Jonathan R; Kim, Jungyeon; Cecchin, Denis; Hindley, James; Pyne, Alice L B; Gaitzsch, Jens; Battaglia, Giuseppe; Howorka, Stefan

    2016-09-01

    Chemistry plays a crucial role in creating synthetic analogues of biomacromolecular structures. Of particular scientific and technological interest are biomimetic vesicles that are inspired by natural membrane compartments and organelles but avoid their drawbacks, such as membrane instability and limited control over cargo transport across the boundaries. In this study, completely synthetic vesicles were developed from stable polymeric walls and easy-to-engineer membrane DNA nanopores. The hybrid nanocontainers feature selective permeability and permit the transport of organic molecules of 1.5 nm size. Larger enzymes (ca. 5 nm) can be encapsulated and retained within the vesicles yet remain catalytically active. The hybrid structures constitute a new type of enzymatic nanoreactor. The high tunability of the polymeric vesicles and DNA pores will be key in tailoring the nanocontainers for applications in drug delivery, bioimaging, biocatalysis, and cell mimicry. PMID:27560310

  17. Electrochemical characterization of hydrogels for biomimetic applications

    DEFF Research Database (Denmark)

    Peláez, L.; Romero, V.; Escalera, S.;

    2011-01-01

    ) or a photoinitiator (P) to encapsulate and stabilize biomimetic membranes for novel separation technologies or biosensor applications. In this paper, we have investigated the electrochemical properties of the hydrogels used for membrane encapsulation. Specifically, we studied the crosslinked hydrogels by using...... electrochemical impedance spectroscopy (EIS), and we demonstrated that chemically crosslinked hydrogels had lower values for the effective electrical resistance and higher values for the electrical capacitance compared with hydrogels with photoinitiated crosslinking. Transport numbers were obtained using......〉 and 〈Pw〉 values than PEG‐1000‐DMA‐P and PEG‐400‐DA‐P hydrogels. In conclusion, our results show that hydrogel electrochemical properties can be controlled by the choice of polymer and type of crosslinking used and that their water and salt permeability properties are congruent with the use of hydrogels...

  18. Biomimetic Membrane Arrays on Cast Hydrogel Supports

    DEFF Research Database (Denmark)

    Roerdink-Lander, Monique; Ibragimova, Sania; Rein Hansen, Christian;

    2011-01-01

    , provides mechanical support but at the cost of small molecule transport through the membrane−support sandwich. To stabilize biomimetic membranes while allowing transport through a membrane−support sandwich, we have investigated the feasibility of using an ethylene tetrafluoroethylene (ETFE)/hydrogel...... sandwich as the support. The sandwich is realized as a perforated surface-treated ETFE film onto which a hydrogel composite support structure is cast. We report a simple method to prepare arrays of lipid bilayer membranes with low intrinsic electrical conductance on the highly permeable, self......-supporting ETFE/hydrogel sandwiches. We demonstrate how the ETFE/hydrogel sandwich support promotes rapid self-thinning of lipid bilayers suitable for hosting membrane-spanning proteins....

  19. Biomimetics for architecture & design nature, analogies, technology

    CERN Document Server

    Pohl, Göran

    2015-01-01

    This book provides the readers with a timely guide to the application of biomimetic principles in architecture and engineering design. As a result of a combined effort by two internationally recognized authorities, the biologist Werner Nachtigall and the architect Göran Pohl, the book describes the principles which can be used to compare nature and technology, and at the same time it presents detailed explanations and examples showing how biology can be used as a source of inspiration and “translated” in building and architectural solutions (biomimicry). Even though nature cannot be directly copied, the living world can provide architects and engineers with a wealth of analogues and inspirations for their own creative designs. But how can analysis of natural entities give rise to advanced and sustainable design? By reporting on the latest bionic design methods and using extensive artwork, the book guides readers through the field of nature-inspired architecture, offering an extraordinary resource for pro...

  20. Development of a Biomimetic Quadruped Robot

    Institute of Scientific and Technical Information of China (English)

    Thanhtam Ho; Sunghac Choi; Sangyoon Lee

    2007-01-01

    This paper presents the design and prototype of a small quadruped robot whose walking motion is realized by two piezocomposite actuators. In the design, biomimetic ideas are employed to obtain the agility of motions and sustainability of a heavy load. The design of the robot legs is inspired by the leg configuration of insects, two joints (hip and knee) of the leg enable two basic motions, lifting and stepping. The robot frame is designed to have a slope relative to the horizontal plane, which makes the robot move forward. In addition, the bounding locomotion of quadruped animals is implemented in the robot. Experiments show that the robot can carry an additional load of about 100 g and run with a fairly high velocity. The quadruped prototype can be an important step towards the goal of building an autonomous mobile robot actuated by piezocomposite actuators.

  1. Biomimetic artificial sphincter muscles: status and challenges

    Science.gov (United States)

    Leung, Vanessa; Fattorini, Elisa; Karapetkova, Maria; Osmani, Bekim; Töpper, Tino; Weiss, Florian; Müller, Bert

    2016-04-01

    Fecal incontinence is the involuntary loss of bowel content and affects more than 12% of the adult population, including 45% of retirement home residents. Severe fecal incontinence is often treated by implanting an artificial sphincter. Currently available implants, however, have long-term reoperation rates of 95% and definitive explantation rates of 40%. These statistics show that the implants fail to reproduce the capabilities of the natural sphincter and that the development of an adaptive, biologically inspired implant is required. Dielectric elastomer actuators (DEA) are being developed as artificial muscles for a biomimetic sphincter, due to their suitable response time, reaction forces, and energy consumption. However, at present the operation voltage of DEAs is too high for artificial muscles implanted in the human body. To reduce the operating voltage to tens of volts, we are using microfabrication to reduce the thickness of the elastomer layer to the nanometer level. Two microfabrication methods are being investigated: molecular beam deposition and electrospray deposition. This communication covers the current status and a perspective on the way forward, including the long-term prospects of constructing a smart sphincter from low-voltage sensors and actuators based on nanometer-thin dielectric elastomer films. As DEA can also provide sensory feedback, a biomimetic sphincter can be designed in accordance with the geometrical and mechanical parameters of its natural counterpart. The availability of such technology will enable fast pressure adaption comparable to the natural feedback mechanism, so that tissue atrophy and erosion can be avoided while maintaining continence du ring daily activities.

  2. Biomimetic oral mucin from polymer micelle networks

    Science.gov (United States)

    Authimoolam, Sundar Prasanth

    Mucin networks are formed by the complexation of bottlebrush-like mucin glycoprotein with other small molecule glycoproteins. These glycoproteins create nanoscale strands that then arrange into a nanoporous mesh. These networks play an important role in ensuring surface hydration, lubricity and barrier protection. In order to understand the functional behavior in mucin networks, it is important to decouple their chemical and physical effects responsible for generating the fundamental property-function relationship. To achieve this goal, we propose to develop a synthetic biomimetic mucin using a layer-by-layer (LBL) deposition approach. In this work, a hierarchical 3-dimensional structures resembling natural mucin networks was generated using affinity-based interactions on synthetic and biological surfaces. Unlike conventional polyelectrolyte-based LBL methods, pre-assembled biotin-functionalized filamentous (worm-like) micelles was utilized as the network building block, which from complementary additions of streptavidin generated synthetic networks of desired thickness. The biomimetic nature in those synthetic networks are studied by evaluating its structural and bio-functional properties. Structurally, synthetic networks formed a nanoporous mesh. The networks demonstrated excellent surface hydration property and were able capable of microbial capture. Those functional properties are akin to that of natural mucin networks. Further, the role of synthetic mucin as a drug delivery vehicle, capable of providing localized and tunable release was demonstrated. By incorporating antibacterial curcumin drug loading within synthetic networks, bacterial growth inhibition was also demonstrated. Thus, such bioactive interfaces can serve as a model for independently characterizing mucin network properties and through its role as a drug carrier vehicle it presents exciting future opportunities for localized drug delivery, in regenerative applications and as bio

  3. Multi-Layer Electrospun Membrane Mimicking Tendon Sheath for Prevention of Tendon Adhesions

    Directory of Open Access Journals (Sweden)

    Shichao Jiang

    2015-03-01

    Full Text Available Defect of the tendon sheath after tendon injury is a main reason for tendon adhesions, but it is a daunting challenge for the biomimetic substitute of the tendon sheath after injury due to its multi-layer membrane-like structure and complex biologic functions. In this study, a multi-layer membrane with celecoxib-loaded poly(l-lactic acid-polyethylene glycol (PELA electrospun fibrous membrane as the outer layer, hyaluronic acid (HA gel as middle layer, and PELA electrospun fibrous membrane as the inner layer was designed. The anti-adhesion efficacy of this multi-layer membrane was compared with a single-layer use in rabbit flexor digitorum profundus tendon model. The surface morphology showed that both PELA fibers and celecoxib-loaded PELA fibers in multi-layer membrane were uniform in size, randomly arrayed, very porous, and smooth without beads. Multi-layer membrane group had fewer peritendinous adhesions and better gliding than the PELA membrane group and control group in gross and histological observation. The similar mechanical characteristic and collagen expression of tendon repair site in the three groups indicated that the multi-layer membrane did not impair tendon healing. Taken together, our results demonstrated that such a biomimetic multi-layer sheath could be used as a potential strategy in clinics for promoting tendon gliding and preventing adhesion without poor tendon healing.

  4. The Promotion of Human Neural Stem Cells Adhesion Using Bioinspired Poly(norepinephrine Nanoscale Coating

    Directory of Open Access Journals (Sweden)

    Minah Park

    2014-01-01

    Full Text Available The establishment of versatile biomaterial interfaces that can facilitate cellular adhesion is crucial for elucidating the cellular processes that occur on biomaterial surfaces. Furthermore, biomaterial interfaces can provide physical or chemical cues that are capable of stimulating cellular behaviors by regulating intracellular signaling cascades. Herein, a method of creating a biomimetic functional biointerface was introduced to enhance human neural stem cell (hNSC adhesion. The hNSC-compatible biointerface was prepared by the oxidative polymerization of the neurotransmitter norepinephrine, which generates a nanoscale organic thin layer, termed poly(norepinephrine (pNE. Due to its adhesive property, pNE resulted in an adherent layer on various substrates, and pNE-coated biointerfaces provided a highly favorable microenvironment for hNSCs, with no observed cytotoxicity. Only a 2-hour incubation of hNSCs was required to firmly attach the stem cells, regardless of the type of substrate. Importantly, the adhesive properties of pNE interfaces led to micropatterns of cellular attachment, thereby demonstrating the ability of the interface to organize the stem cells. This highly facile surface-modification method using a biomimetic pNE thin layer can be applied to a number of suitable materials that were previously not compatible with hNSC technology.

  5. Simplified model of underwater electrical discharge.

    Science.gov (United States)

    Gurovich, V Ts; Grinenko, A; Krasik, Ya E; Felsteiner, J

    2004-03-01

    A model of the underwater discharge with initiating wire is presented. The model reveals the nature of similarity parameters which have been phenomenologically introduced in earlier experimental research in order to predict behavior of different discharges. It is shown that these parameters naturally appear as a result of the normalization of differential equations, which determines the process of underwater wire initiated discharge. In these equations the energy conservation law for wire material evaporation and the dependence of plasma conductivity on the energy dissipated in the discharge are implied to calculate the time varying resistance of the discharge gap. The comparison of calculations with the experimental results shows that good agreement is achieved when modification of these parameters is introduced. These new similarity parameters are functions of the original similarity parameters, hence the law of the similarity of underwater electrical discharge is preserved. PMID:15089410

  6. Survivability design for a hybrid underwater vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Biao; Wu, Chao; Li, Xiang; Zhao, Qingkai; Ge, Tong [State Key Lab of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-03-10

    A novel hybrid underwater robotic vehicle (HROV) capable of working to the full ocean depth has been developed. The battery powered vehicle operates in two modes: operate as an untethered autonomous vehicle in autonomous underwater vehicle (AUV) mode and operate under remote control connected to the surface vessel by a lightweight, fiber optic tether in remotely operated vehicle (ROV) mode. Considering the hazardous underwater environment at the limiting depth and the hybrid operating modes, survivability has been placed on an equal level with the other design attributes of the HROV since the beginning of the project. This paper reports the survivability design elements for the HROV including basic vehicle design of integrated navigation and integrated communication, emergency recovery strategy, distributed architecture, redundant bus, dual battery package, emergency jettison system and self-repairing control system.

  7. The Future Deep Underwater Space Station

    Directory of Open Access Journals (Sweden)

    Jianjun Yao

    2013-08-01

    Full Text Available The purpose of the study is to provide an idea of developing an underwater space station. Though the ocean covers about 71% of the surface of the Earth and holds tremendous amount of resources, it is still an unknown field for human beings. With the depletion of natural resources on the land, there is an urgent need to explore and exploit the ocean, but this process is constrained by the ocean engineering equipment and technology. The study proposed a sketch of a deep sea space station, which is similar to the International space station. The station can applied to observe the ocean environment, generate power from the ocean energy, manage to mine resources, control underwater factories and underwater vehicles, be habitable for staff, making another space for human.

  8. Magnetic gradiometer for underwater detection applications

    Science.gov (United States)

    Kumar, S.; Skvoretz, D. C.; Moeller, C. R.; Ebbert, M. J.; Perry, A. R.; Ostrom, R. K.; Tzouris, A.; Bennett, S. L.; Czipott, P. V.; Sulzberger, G.; Allen, G. I.; Bono, J.; Clem, T. R.

    2006-05-01

    We have designed and constructed a magnetic gradiometer for underwater mine detection, location and tracking. The United States Naval Surface Warfare Center (NSWC PC) in Panama City, FL has conducted sea tests of the system using an unmanned underwater vehicle (UUV). The Real-Time Tracking Gradiometer (RTG) measures the magnetic field gradients caused by the presence of a mine in the Earth's magnetic field. These magnetic gradients can then be used to detect and locate a target with the UUV in motion. Such a platform can also be used for other applications, including the detection and tracking of vessels and divers for homeland (e.g., port) security and the detection of underwater pipelines. Data acquired by the RTG in sea tests is presented in this paper.

  9. Application of time reversal in underwater communication

    Institute of Scientific and Technical Information of China (English)

    LU Minghui; ZHANG Bixing; WANG Chenghao

    2004-01-01

    Time reversal is applied to the underwater spreading spectrum coding communication. On the base of analyzing the focusing characteristics of the time reversal in underwater waveguide, the time reversal is studied to overcome the wave distortion of the encoded signal caused by the multi-path effect. The experiment research for underwater coding communication is carried out in a lab water tank and the corresponding theoretical analysis is also conducted by Binary Phase Shift Keying (BPSK) encoding and Barker code with 7 chips for the spreading spectrum signal. The results show that the time reversal can improve the focusing gain and increase the ratio of the principal to the second lobe of the coding signal, and can decrease the bit error rate and increase the communication distance.

  10. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  11. Electro-dry-adhesion.

    Science.gov (United States)

    Krahn, Jeffrey; Menon, Carlo

    2012-03-27

    This work presents novel conductive bioinspired dry adhesives with mushroom caps that enable the use of a synergistic combination of electrostatic and van der Waals forces (electro-dry-adhesion). An increase in shear adhesion bond strength of up to 2046% on a wide range of materials is measured when a maximum electrical field of 36.4 V μm(-1) is applied. A suction effect, due to the shape of the dry adhesive fibers, on overall adhesion was not noted for electro-dry-adhesives when testing was performed at both atmospheric and reduced pressure. Utilization of electrostatics to apply a preloading force to dry adhesive fiber arrays allows increased adhesion even after electrostatic force generation has been halted by ensuring the close contact necessary for van der Waals forces to be effective. A comparison is made between self-preloading of the electro-dry-adhesives and the direct application of a normal preloading pressure resulting in nearly the same shear bond strength with an applied voltage of 3.33 kV on the same sample.

  12. DESIGN OPTIMISATION OF AN UNMANNED UNDERWATER VEHICLE

    Directory of Open Access Journals (Sweden)

    FIRDAUS ABDULLAH

    2007-08-01

    Full Text Available The results of fluid flow simulation around an unmanned underwater vehicle (UUV are presented in this paper. The UUV represents a small submarine for underwater search and rescue operation, which suits the local river conditions. The flow simulation was performed with a commercially available computational fluid dynamics package, Star-CD. The effects of the UUV geometry on the velocity and pressure distributions on the UUV surface were discussed for Re=500,000 and 3,000,000. The discussion led to an improved design of the UUV with a smoother velocity profile around the UUV body.

  13. Modulation Method of Laser for Underwater Communication

    Directory of Open Access Journals (Sweden)

    J. P. Singhal

    1984-01-01

    Full Text Available Due to very high absorption of light in the water it is necessary to use high energy pulsed bluegreen lasers for underwater communication systems. However,these lasers do not have high repetition rates, sufficient enough to support high data rate signals. The pulse interval modulation method is one of the prospective methods of sending large bandwidth data using low frequency (500 to1000 pulses per second pulsed laser. This method appears to be more promising for underwater communication system with likely development of fast PIM coder/decoder.

  14. Controllable underwater anisotropic oil-wetting

    Energy Technology Data Exchange (ETDEWEB)

    Yong, Jiale; Chen, Feng, E-mail: chenfeng@mail.xjtu.edu.cn; Yang, Qing; Farooq, Umar; Bian, Hao; Du, Guangqing; Hou, Xun [State Key Laboratory for Manufacturing System Engineering and Key Laboratory of Photonics Technology for Information of Shaanxi Province, School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2014-08-18

    This Letter demonstrates a simple method to achieve underwater anisotropic oil-wetting using silicon surfaces with a microgroove array produced by femtosecond laser ablation. The oil contact angles along the direction perpendicular to the grooves are consistently larger than those parallel to the microgroove arrays in water because the oil droplet is restricted by the energy barrier that exists between the non-irradiated domain and the trapped water in the laser-ablated microgrooves. This underwater anisotropic oil-wetting is able to be controlled, and the anisotropy can be tuned from 0° to ∼20° by adjusting the period of the microgroove arrays.

  15. Efficient Modelling Methodology for Reconfigurable Underwater Robots

    DEFF Research Database (Denmark)

    Nielsen, Mikkel Cornelius; Blanke, Mogens; Schjølberg, Ingrid

    2016-01-01

    This paper considers the challenge of applying reconfigurable robots in an underwater environment. The main result presented is the development of a model for a system comprised of N, possibly heterogeneous, robots dynamically connected to each other and moving with 6 Degrees of Freedom (DOF......). This paper presents an application of the Udwadia-Kalaba Equation for modelling the Reconfigurable Underwater Robots. The constraints developed to enforce the rigid connection between robots in the system is derived through restrictions on relative distances and orientations. To avoid singularities...

  16. Biomimetic anchors applied to the host-guest antifouling functionalization of titanium substrates.

    Science.gov (United States)

    Cai, Xiao Yan; Li, Ning Ning; Chen, Jiu Cun; Kang, En-Tang; Xu, Li Qun

    2016-08-01

    A biomimetic strategy was developed for the construction of antifouling titanium oxide (Ti(oxide)) surfaces based on host-guest interactions. Two catecholic derivatives, dopamine 4-(phenylazo)benzamide (AZODopa) and dopamine 1-adamantanecarboxamide (AdaDopa) were synthesized and immobilized onto the Ti(oxide) surfaces. The guest molecules-anchored Ti(oxide) surfaces were further functionalized with zwitterionic heptakis[6-deoxy-6-(N-3-sulfopropyl-N,N-dimethylammonium ethyl sulfanyl)]-β-cyclodextrin (SBCD) and hydrophilic β-CD polymer (CDP). The surface elemental compositions and hydrophobic/hydrophilic properties of the Ti(oxide) surfaces before and after modification were characterized by X-ray photoelectron spectroscopy (XPS) and static water contact angle measurements, respectively. The antifouling properties of the modified Ti(oxide) surfaces were evaluated by the protein adsorption and bacterial adhesion assays. The zwitterionic SBCD- and hydrophilic CDP-functionalized Ti(oxide) surfaces can reduce the adsorption of bovine plasma fibrinogen and adhesion of Escherichia coli, as compared to the pristine and guest molecules-anchored Ti(oxide) surfaces. PMID:27135943

  17. Design and Dynamic Analysis of a Novel Biomimetic Robotics Hip Joint

    OpenAIRE

    Bingyan Cui; Liwen Chen; Zhijun Wang; Yuanhao Zhao; Zhanxian Li; Zhenlin Jin

    2015-01-01

    In order to increase the workspace and the carrying capacity of biomimetic robotics hip joint, a novel biomimetic robotics hip joint was developed. The biomimetic robotics hip joint is mainly composed of a moving platform, frame, and 3-RRR orthogonal spherical parallel mechanism branched chains, and has the characteristics of compact structure, large bearing capacity, high positioning accuracy, and good controllability. The functions of the biomimetic robotics hip joint are introduced, such a...

  18. Fabrication of biomimetic nanomaterials and their effect on cell behavior

    Science.gov (United States)

    Porri, Teresa Jane

    Cells in vivo respond to an intricate combination of chemical and mechanical signals. The corneal epithelium, a structure which prevents the admission of bacteria and undesirable molecules into the eye, grows on a basement membrane which presents both nanoscale topographic and adhesive chemical signals. An effective approach to biomaterials design takes advantage of the synergistic effects of the multiple cellular inputs which are available to engineer cell-substrate interactions. We have previously demonstrated the effects of nanoscale topography on a variety of corneal epithelial cell behaviors. To gain a better understanding of cell-level control in vivo, we employ a systems-level approach which looks at the effect of nanoscale topography in conjunction with a biomimetic surface chemistry. First, we discuss a novel method of fabricating nanoscale topography through templated electroless deposition of gold into PVP-coated polycarbonate membranes. This technique creates nanowires of gold with an uniform outer diameter that is dependent upon the size of the pores in the membrane used, and a nanowire length that is dependent upon the extent of etching into the polymer membrane. The gold nanowires can be modified with self-assembled monolayers (SAMs) of alkanethiols. Using these substrates, we study the effect of topographic length scale and surface chemistry on cells attached to a discontinuous nanoscale topography, and find a transition in cellular behavior at a length scale (between 600 and 2000 nm inter-wire spacing) that is commensurate with the transition length scale seen on surfaces presenting continuous grooves and ridges. Secondly, we study the effect of non-fouling peptide-modified SAMs on cellular behavior. We examine the effect of co-presented RGD and AG73 peptides and show that cell spreading is a function of the relative ratios of RGD and AG73 present on the surface. Finally, we explore the combinatorial effects of biologically relevant chemistry with

  19. Biomimetic oligosaccharide and peptide surfactant polymers designed for cardiovascular biomaterials

    Science.gov (United States)

    Ruegsegger, Mark Andrew

    A common problem associated with cardiovascular devices is surface induced thrombosis initiated by the rapid, non-specific adsorption of plasma proteins onto the biomaterial surface. Control of the initial protein adsorption is crucial to achieve the desired longevity of the implanted biomaterial. The cell membrane glycocalyx acts as a non-thrombogenic interface through passive (dense oligosaccharide structures) and active (ligand/receptor interactions) mechanisms. This thesis is designed to investigate biomimicry of the cell glycocalyx to minimize non-specific protein adsorption and promote specific ligand/receptor interactions. Biomimetic macromolecules were designed through the molecular-scale engineering of polymer surfactants, utilizing a poly(vinyl amine) (PVAm) backbone to which hydrophilic (dextran, maltose, peptide) and hydrophobic alkyl (hexanoyl or hexanal) chains are simultaneously attached. The structure was controlled through the molar feed ratio of hydrophobic-to-hydrophilic groups, which also provided control of the solution and surface-active properties. To mimic passive properties, a series of oligomaltose surfactants were synthesized with increasing saccharide length (n = 2, 7, 15 where n is number of glucose units) to investigate the effect of coating height on protein adsorption. The surfactants were characterized by infra red (IR) and nuclear magnetic resonance (NMR) spectroscopies for structural properties and atomic force microscopy (AFM) and contact angle goniometry for surface activity. Protein adsorption under dynamic flow (5 dyn/cm2) was reduced by 85%--95% over the bare hydrophobic substrate; platelet adhesion dropped by ˜80% compared to glass. Peptide ligands were incorporated into the oligosaccharide surfactant to promote functional activity of the passive coating. The surfactants were synthesized to contain 0%, 25%, 50%, 75%, and 100% peptide ligand density and were stable on hydrophobic surfaces. The peptide surface density was

  20. IVO develops a new repair technique for underwater sites. Viscous doughlike substance underwater cracks

    Energy Technology Data Exchange (ETDEWEB)

    Klingstedt, G.; Leisio, C. [ed.

    1998-07-01

    A viscous sealant is revolutionizing repair of the stone and concrete masonry of underwater dams, bridges and canals. There is now no need for expensive and time-consuming cofferdams, since a diver can extrude quick-setting mortar into underwater structures needing repair. This technique has worked well in recent years in various parts of Finland even in strongly flowing water. IVO experts are now starting to look more beyond the borders of Finland

  1. Acoustic underwater navigation of the Phoenix Autonomous Underwater Vehicle using the DiveTracker system

    OpenAIRE

    Scrivener, Arthur W.

    1996-01-01

    Autonomous Underwater Vehicles (AUVs) require a navigation system in order to conduct useful functions. This research was an experimental investigation of the commercial DiveTracker underwater acoustic navigation system used onboard the NPS Phoenix AUV. Tests conducted with the DiveTracker system proved that the system could be used successfully in AUV navigation while submerged and revealed that more precise positioning could be obtained through postconditioning of the DiveTracker output ran...

  2. Need and Role of Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Tajinder Singh

    2013-07-01

    Full Text Available The field of underwater acoustic sensor networking is growing rapidly thanks to the key role it plays in many military and commercial applications. Among these are disaster prevention, tactical surveillance, offshore exploration, pollution monitoring and oceanographic data collection. Moreover, unmanned or autonomous underwater vehicles (UUVs, AUVs, equipped with sensors, will enable the exploration of natural undersea resources and gathering of scientific data in collaborative monitoring missions. Underwater acoustic networking is the enabling technology for these applications. The objective of this paper is to understand several fundamental key aspects of underwater acoustic communications. Different architectures for two-dimensional and three-dimensional underwater sensor networks are discussed, and the characteristics of the underwater channel are detailed. The main challenges for the development of efficient networking solutions posed by the underwater environment are detailed. This paper also presents a detailed explanation of the sensor networks used in tsunami detection. We then present an overview of the recent advances

  3. Application of MATLAB in pretreatment technology of the underwater images

    International Nuclear Information System (INIS)

    The technology of underwater laser imaging has very important practical value at ocean exploitation such as underwater reconnaissance, target recognition, but its imagery is usually affected by speckle noise. A large number of background noise are brought to underwater laser image for the reasons of absorption and scattering of water, which is also the cause of noises and low contrast of the underwater images. In order to improve the effect of the images, digital image processing techniques are introduced. The result of underwater image processing acts as the input of feature extraction and recognition of the underwater objects. Histogram equalization, contrast enhancement, smoothing filtering are applied to process the blurry underwater laser images. The results of the experiment show these application of Matlab are effective and applicable. (authors)

  4. Simplified scheduling for underwater acoustic networks

    NARCIS (Netherlands)

    Kleunen, van Wouter; Meratnia, Nirvana; Havinga, Paul J.M.

    2013-01-01

    The acoustic propagation speed under water poses significant challenges to the design of underwater sensor networks and their medium access control protocols. Similar to the air, scheduling transmissions under water has significant impact on throughput, energy consumption, and reliability. In this p

  5. Underwater noise generated by offshore pile driving

    NARCIS (Netherlands)

    Tsouvalas, A.

    2015-01-01

    Anthropogenic noise emission in the marine environment has always been an environmental issue of serious concern. In particular, the noise generated during the installation of foundation piles is considered to be one of the most significant sources of underwater noise pollution. This is mainly attri

  6. Impacts of underwater noise on marine vertebrates

    NARCIS (Netherlands)

    Liebschner, Alexander; Seibel, Henrike; Teilmann, Jonas; Wittekind, Dietrich; Parmentier, Eric; Dähne, Michael; Dietz, Rune; Driver, Jörg; Elk, van Cornelis; Everaarts, Eligius; Findeisen, Henning; Kristensen, Jacob; Lehnert, Kristina; Lucke, Klaus; Merck, Thomas; Müller, Sabine; Pawliczka, Iwona; Ronnenberg, Katrin; Rosenberger, Tanja; Ruser, Andreas; Tougaard, Jakob; Schuster, Max; Sundermeyer, Janne; Sveegaard, Signe; Siebert, Ursula

    2016-01-01

    The project conducts application-oriented research on impacts of underwater noise on marine vertebrates in the North and Baltic Seas. In distinct subprojects, the hearing sensitivity of harbor porpoises and gray seals as well as the acoustic tolerance limit of harbor porpoises to impulsive noise

  7. Tissue adhesives in otorhinolaryngology

    Directory of Open Access Journals (Sweden)

    Schneider, Gerlind

    2009-01-01

    Full Text Available The development of medical tissue adhesives has a long history without finding an all-purpose tissue adhesive for clinical daily routine. This is caused by the specific demands which are made on a tissue adhesive, and the different areas of application. In otorhinolaryngology, on the one hand, this is the mucosal environment as well as the application on bones, cartilage and periphery nerves. On the other hand, there are stressed regions (skin, oral cavity, pharynx, oesophagus, trachea and unstressed regions (middle ear, nose and paranasal sinuses, cranial bones. But due to the facts that adhesives can have considerable advantages in assuring surgery results, prevention of complications and so reduction of medical costs/treatment expenses, the search for new adhesives for use in otorhinolaryngology will be continued intensively. In parallel, appropriate application systems have to be developed for microscopic and endoscopic use.

  8. Communication and cooperation in underwater acoustic networks

    Science.gov (United States)

    Yerramalli, Srinivas

    In this thesis, we present a study of several problems related to underwater point to point communications and network formation. We explore techniques to improve the achievable data rate on a point to point link using better physical layer techniques and then study sensor cooperation which improves the throughput and reliability in an underwater network. Robust point-to-point communications in underwater networks has become increasingly critical in several military and civilian applications related to underwater communications. We present several physical layer signaling and detection techniques tailored to the underwater channel model to improve the reliability of data detection. First, a simplified underwater channel model in which the time scale distortion on each path is assumed to be the same (single scale channel model in contrast to a more general multi scale model). A novel technique, which exploits the nature of OFDM signaling and the time scale distortion, called Partial FFT Demodulation is derived. It is observed that this new technique has some unique interference suppression properties and performs better than traditional equalizers in several scenarios of interest. Next, we consider the multi scale model for the underwater channel and assume that single scale processing is performed at the receiver. We then derive optimized front end pre-processing techniques to reduce the interference caused during single scale processing of signals transmitted on a multi-scale channel. We then propose an improvised channel estimation technique using dictionary optimization methods for compressive sensing and show that significant performance gains can be obtained using this technique. In the next part of this thesis, we consider the problem of sensor node cooperation among rational nodes whose objective is to improve their individual data rates. We first consider the problem of transmitter cooperation in a multiple access channel and investigate the stability of

  9. Tubular inverse opal scaffolds for biomimetic vessels

    Science.gov (United States)

    Zhao, Ze; Wang, Jie; Lu, Jie; Yu, Yunru; Fu, Fanfan; Wang, Huan; Liu, Yuxiao; Zhao, Yuanjin; Gu, Zhongze

    2016-07-01

    There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels.There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially

  10. Biomimetic electrochemistry from conducting polymers. A review

    International Nuclear Information System (INIS)

    Highlights: ► Composition and properties of conducting polymers change during reactions. ► These properties are being exploited to develop biomimetic reactive and soft devices. ► The state of the art for artificial muscles sensing working conditions was reviewed. ► Smart membranes, drug delivery devices and nervous interfaces were also reviewed. - Abstract: Films of conducting polymers in the presence of electrolytes can be oxidized or reduced by the flow of anodic or cathodic currents. Ions and solvent are exchanged during a reaction for charge and osmotic pressure balance. A reactive conducting polymer contains ions and solvent. Such variation of composition during a reaction is reminiscent of the biological processes in cells. Along changes to the composition of the material during a reaction, there are also changes to other properties, including: volume (electrochemomechanical), colour (electrochromic), stored charge (electrical storage), porosity or permselectivity (electroporosity), stored chemicals, wettability and so on. Most of those properties mimic similar property changes in organs during their functioning. These properties are being exploited to develop biomimetic reactive and soft devices: artificial muscles and polymeric actuators; supercapacitors and all organic batteries; smart membranes; electron-ion transducers; nervous interfaces and artificial synapses, or drug delivery devices. In this review we focus on the state of the art for artificial muscles, smart membranes and electron-ion transducers. The reactive nature of those devices provide them with a unique advantage related to the present days technologies: any changes in the surrounding physical or chemical variable acting on the electrochemical reaction rate will be sensed by the device while working. Working under constant current (driving signal), the evolution of the device potential or the evolution of the consumed electrical energy (sensing signals) senses and quantifies the

  11. Biomimetics: forecasting the future of science, engineering, and medicine

    Directory of Open Access Journals (Sweden)

    Hwang J

    2015-09-01

    Full Text Available Jangsun Hwang,1 Yoon Jeong,1,2 Jeong Min Park,3 Kwan Hong Lee,1,2,4 Jong Wook Hong,1,2 Jonghoon Choi1,2 1Department of Bionano Technology, Graduate School, Hanyang University, Seoul, 2Department of Bionano Engineering, Hanyang University ERICA, Ansan, Korea; 3Department of Biomedical Engineering, Boston University, 4OpenView Venture Partners, Boston, MA, USA Abstract: Biomimetics is the study of nature and natural phenomena to understand the principles of underlying mechanisms, to obtain ideas from nature, and to apply concepts that may benefit science, engineering, and medicine. Examples of biomimetic studies include fluid-drag reduction swimsuits inspired by the structure of shark’s skin, velcro fasteners modeled on burrs, shape of airplanes developed from the look of birds, and stable building structures copied from the backbone of turban shells. In this article, we focus on the current research topics in biomimetics and discuss the potential of biomimetics in science, engineering, and medicine. Our report proposes to become a blueprint for accomplishments that can stem from biomimetics in the next 5 years as well as providing insight into their unseen limitations. Keywords: biomimicry, tissue engineering, biomaterials, nature, nanotechnology, nanomedicine

  12. BatSLAM: Simultaneous localization and mapping using biomimetic sonar.

    Directory of Open Access Journals (Sweden)

    Jan Steckel

    Full Text Available We propose to combine a biomimetic navigation model which solves a simultaneous localization and mapping task with a biomimetic sonar mounted on a mobile robot to address two related questions. First, can robotic sonar sensing lead to intelligent interactions with complex environments? Second, can we model sonar based spatial orientation and the construction of spatial maps by bats? To address these questions we adapt the mapping module of RatSLAM, a previously published navigation system based on computational models of the rodent hippocampus. We analyze the performance of the proposed robotic implementation operating in the real world. We conclude that the biomimetic navigation model operating on the information from the biomimetic sonar allows an autonomous agent to map unmodified (office environments efficiently and consistently. Furthermore, these results also show that successful navigation does not require the readings of the biomimetic sonar to be interpreted in terms of individual objects/landmarks in the environment. We argue that the system has applications in robotics as well as in the field of biology as a simple, first order, model for sonar based spatial orientation and map building.

  13. Effects of Biomimetic Surface Designs on Furrow Opener Performance

    Institute of Scientific and Technical Information of China (English)

    Jin Tong; Ballel. Z. Moayad; Yun-hai Ma; Ji-yu Sun; Dong-hui Chen; Hong-lei Jia; Lu-quan Ren

    2009-01-01

    The effects of biomimetic designs of tine furrow opener surface on equivalent pressure and pressure in the direction of motion on opener surface against soil were studied by finite element method (FEM) simulation and the effects of these designs on tool force and power requirements were examined experimentally. Geometrical structures of the cuticle surfaces of dung beetle (Copris ochus Motschulsky) were examined by stereoscopy. The structures of the cuticle surfaces and Ultra High Mo-lecular Weight Polyethylene (UHMWPE) material were modeled on surface of tine furrow opener as biomimetic designs. Seven furrow openers were analyzed in ANSYS program (a FEM simulation software). The biomimetic furrow opener surfaces with UHMWPE structures were found to have lower equivalent pressure and pressure in the direction of motion as compared to the conventional surface and to the biomimetic surfaces with textured steel-35 structures. It was found that the tool force and power were increased with the cutting depth and operating speed and the biomimetic furrow opener with UHMWPE tubular section ridges showed the lowest resistance and power requirement against soil.

  14. Sustainability assessment of a lightweight biomimetic ceiling structure

    International Nuclear Information System (INIS)

    An intensive and continuous debate centres on the question of whether biomimetics has a specific potential to contribute to sustainability. In the context of a case study, the objective of this paper is to contribute to this debate by presenting the first systematic approach to assess the sustainability of a complex biomimetic product. The object of inquiry is a lecture hall's ribbed slab. Based on criteria suggested by the Association of German Engineers (VDI), it has been verified that the slab has been correctly defined as biomimetic. Moreover, a systematic comparative product sustainability assessment has been carefully carried out. For purposes of comparison, estimated static calculations have been performed for conceivable current state-of-the-art lightweight ceiling structures. Alternative options are a hollow article slab and a pre-stressed flat slab. Besides a detailed benefit analysis and a discussion of social effects, their costs have also been compared. A particularly detailed life cycle assessment on the respective environmental impacts has also been performed. Results show that the biomimetic ribbed slab built in the 1960s is able to keep up with the current state-of-the-art lightweight solutions in terms of sustainability. These promising results encourage a systematic search for a broad range of sustainable biomimetic solutions. (paper)

  15. Numerical Analysis of Erosion Caused by Biomimetic Axial Fan Blade

    Directory of Open Access Journals (Sweden)

    Jun-Qiu Zhang

    2013-01-01

    Full Text Available Damage caused by erosion has been reported in several industries for a wide range of situations. In the present work, a new method is presented to improve the erosion resistance of machine components by biomimetic method. A numerical investigation of solid particle erosion in the standard and biomimetic configuration blade of axial fan is presented. The analysis consists in the application of the discrete phase model, for modeling the solid particles flow, and the Eulerian conservation equations to the continuous phase. The numerical study employs computational fluid dynamics (CFD software, based on a finite volume method. User-defined function was used to define wear equation. Gas/solid flow axial fan was simulated to calculate the erosion rate of the particles on the fan blades and comparatively analyzed the erosive wear of the smooth surface, the groove-shaped, and convex hull-shaped biomimetic surface axial flow fan blade. The results show that the groove-shaped biomimetic blade antierosion ability is better than that of the other two fan blades. Thoroughly analyze of antierosion mechanism of the biomimetic blade from many factors including the flow velocity contours and flow path lines, impact velocity, impact angle, particle trajectories, and the number of collisions.

  16. BatSLAM: Simultaneous localization and mapping using biomimetic sonar.

    Science.gov (United States)

    Steckel, Jan; Peremans, Herbert

    2013-01-01

    We propose to combine a biomimetic navigation model which solves a simultaneous localization and mapping task with a biomimetic sonar mounted on a mobile robot to address two related questions. First, can robotic sonar sensing lead to intelligent interactions with complex environments? Second, can we model sonar based spatial orientation and the construction of spatial maps by bats? To address these questions we adapt the mapping module of RatSLAM, a previously published navigation system based on computational models of the rodent hippocampus. We analyze the performance of the proposed robotic implementation operating in the real world. We conclude that the biomimetic navigation model operating on the information from the biomimetic sonar allows an autonomous agent to map unmodified (office) environments efficiently and consistently. Furthermore, these results also show that successful navigation does not require the readings of the biomimetic sonar to be interpreted in terms of individual objects/landmarks in the environment. We argue that the system has applications in robotics as well as in the field of biology as a simple, first order, model for sonar based spatial orientation and map building.

  17. Conventional vs Biomimetic Approaches to the Exploration of Mars

    Science.gov (United States)

    Ellery, A.

    It is not usual to refer to convention in planetary exploration missions by virtue of the innovation required for such projects. The term conventional refers to the methodologies, tools and approaches typically adopted in engineering that are applied to such missions. Presented is a "conventional" Mars rover mission in which the author was involved - ExoMars - into which is interspersed references to examples where biomimetic approaches may yield superior capabilities. Biomimetics is a relatively recently active area of research which seeks to examine how biological systems solve the problem of survival in the natural environment. Biological organisms are autonomous entities that must survive in a hostile world adapting both adaptivity and robustness. It is not then surprising that biomimetics is particularly useful when applied to robotic elements of a Mars exploration mission. I present a number of areas in which biomimetics may yield new solutions to the problem of Mars exploration - optic flow navigation, potential field navigation, genetically-evolved neuro-controllers, legged locomotion, electric motors implementing muscular behaviour, and a biomimetic drill based on the wood wasp ovipositor. Each of these techniques offers an alternative approach to conventional ones. However, the perceptive hurdles are likely to dwarf the technical hurdles in implementing many of these methods in the near future.

  18. Osteoinductive peptide-functionalized nanofibers with highly ordered structure as biomimetic scaffolds for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Gao X

    2015-11-01

    Full Text Available Xiang Gao,1,2,* Xiaohong Zhang,3,* Jinlin Song,1,2 Xiao Xu,4 Anxiu Xu,1 Mengke Wang,4 Bingwu Xie,1 Enyi Huang,2 Feng Deng,1,2 Shicheng Wei2–41College of Stomatology, 2Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, 3Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, 4Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, Peking University School and Hospital of Stomatology, Beijing, People’s Republic of China*These authors contributed equally to this workAbstract: The construction of functional biomimetic scaffolds that recapitulate the topographical and biochemical features of bone tissue extracellular matrix is now of topical interest in bone tissue engineering. In this study, a novel surface-functionalized electrospun polycaprolactone (PCL nanofiber scaffold with highly ordered structure was developed to simulate the critical features of native bone tissue via a single step of catechol chemistry. Specially, under slightly alkaline aqueous solution, polydopamine (pDA was coated on the surface of aligned PCL nanofibers after electrospinning, followed by covalent immobilization of bone morphogenetic protein-7-derived peptides onto the pDA-coated nanofiber surface. Contact angle measurement, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the presence of pDA and peptides on PCL nanofiber surface. Our results demonstrated that surface modification with osteoinductive peptides could improve cytocompatibility of nanofibers in terms of cell adhesion, spreading, and proliferation. Most importantly, Alizarin Red S staining, quantitative real-time polymerase chain reaction, immunostaining, and Western blot revealed that human mesenchymal stem cells cultured on aligned nanofibers with osteoinductive peptides exhibited enhanced osteogenic differentiation potential than

  19. Biomimetic Coacervate Environments for Protein Analysis

    Science.gov (United States)

    Perry, Sarah; McCall, Patrick; Srivastava, Samavayan; Kovar, David; Gardel, Margaret; Tirrell, Matthew

    2015-03-01

    Living cells have evolved sophisticated intracellular organization strategies that are challenging to reproduce synthetically. Biomolecular function depends on both the structure of the molecule itself and the properties of the surrounding medium. The ability to simulate the in vivo environment and isolate biological networks for study in an artificial milieu without sacrificing the crowding, structure, and compartmentalization of a cellular environment, represent engineering challenges with tremendous potential to impact both biological studies and biomedical applications. Emerging experience has shown that polypeptide-based complex coacervation (electrostatically-driven liquid-liquid phase separation) produces a biomimetic microenvironment capable of tuning protein biochemical activity. We have investigated the effect of polypeptide-based coacervates on the dynamic self-assembly of cytoskeletal actin filaments. Coacervate materials are able to directly affect the nucleation and assembly dynamics. We observe effects that can be attributed to the length and chemical specificity of the encapsulating polypeptides, as well as the overall crowded nature of a polymer-rich coacervate phase. Coacervate-based systems are particularly attractive for use in biochemical assays because the compartmentalization afforded by liquid-liquid phase separation does not necessarily inhibit the transport of molecules across the compartmental barrier.

  20. Mineralization of Zein Films by Biomimetic Process

    Institute of Scientific and Technical Information of China (English)

    JIN Xiaoning; ZHANG Yanxiang; MA Ying; ZENG Sheng; WANG Shaozhen; MA Yalu

    2015-01-01

    The transparent or opaque zein film was prepared by a phase separation method with a zein ethanol aqueous solution. The circular zein film was self-assembled on the air-water interface. According to the images by scanning elec-tron microscopy, the upper surface of film is flat and smooth and the downward surface presents a complex reticulation structure of corn protein fiber. Zein film as a biomimetic mineralization template is used to synthesize calcium phosphate crystals by a bioinspired mineralization process. Randomly oriented apatite crystals appear on the both surfaces of zein film after immersion in 10´simulated body fluid, and the phase composition and morphology of the deposited calcium apatite are also distinguished from deposited location and immersion time. The phase transformation process from dical-cium phosphate dihydrate into hydroxyapatite (HAp) phase was investigated by X-ray powder diffraction, transmission electron microscopy and Fourier transform infrared spectroscopy, respectively. Based on the results by energy dispersive X-ray spectroscopy, the Ca/P ratio of the deposited apatite increases with the transformation from DCPD to HAp. The HAp/Zein films possess the excellent biodegradable structural features, and the coating of HAp crystallites has some potential applications for bone repair and regeneration.

  1. Biomimetic optical sensor for aerospace applications

    Science.gov (United States)

    Frost, Susan A.; Gorospe, George E.; Wright, Cameron H. G.; Barrett, Steven F.

    2015-05-01

    We report on a fiber optic sensor based on the physiological aspects of the eye and vision-related neural layers of the common housefly (Musca domestica) that has been developed and built for aerospace applications. The intent of the research is to reproduce select features from the fly's vision system that are desirable in image processing, including high functionality in low-light and low-contrast environments, sensitivity to motion, compact size, lightweight, and low power and computation requirements. The fly uses a combination of overlapping photoreceptor responses that are well approximated by Gaussian distributions and neural superposition to detect image features, such as object motion, to a much higher degree than just the photoreceptor density would imply. The Gaussian overlap in the biomimetic sensor comes from the front-end optical design, and the neural superposition is accomplished by subsequently combining the signals using analog electronics. The fly eye sensor is being developed to perform real-time tracking of a target on a flexible aircraft wing experiencing bending and torsion loads during flight. We report on results of laboratory experiments using the fly eye sensor to sense a target moving across its field of view.

  2. Biomimetic Pattern Recognition Theory and Its Applications

    Institute of Scientific and Technical Information of China (English)

    WANGShoujue; ZHAOXingtao

    2004-01-01

    Biomimetic pattern recogntion (BPR),which is based on “cognition” instead of “classification”,is much closer to the function of human being. The basis of BPR is the Principle of homology-continuity (PHC),which means the difference between two samples of the same class must be gradually changed. The aim of BPR is to find an optimal covering in the feature space, which emphasizes the “similarity” among homologous group members, rather than “division” in traditional pattern recognition. Some applications of BPR are surveyed, in which the results of BPR are much better than the results of Support Vector Machine. A novel neuron model, Hyper sausage neuron (HSN), is shown as a kind of covering units in BPR. The mathematical description of HSN is given and the 2-dimensional discriminant boundary of HSN is shown. In two special cases, in which samples are distributed in a line segment and a circle, both the HSN networks and RBF networks are used for covering. The results show that HSN networks act better than RBF networks in generalization, especially for small sample set, which are consonant with the results of the applications of BPR. And a brief explanation of the HSN networks' advantages in covering general distributed samples is also given.

  3. Bactericidal activity of biomimetic diamond nanocone surfaces.

    Science.gov (United States)

    Fisher, Leanne E; Yang, Yang; Yuen, Muk-Fung; Zhang, Wenjun; Nobbs, Angela H; Su, Bo

    2016-03-01

    The formation of biofilms on implant surfaces and the subsequent development of medical device-associated infections are difficult to resolve and can cause considerable morbidity to the patient. Over the past decade, there has been growing recognition that physical cues, such as surface topography, can regulate biological responses and possess bactericidal activity. In this study, diamond nanocone-patterned surfaces, representing biomimetic analogs of the naturally bactericidal cicada fly wing, were fabricated using microwave plasma chemical vapor deposition, followed by bias-assisted reactive ion etching. Two structurally distinct nanocone surfaces were produced, characterized, and the bactericidal ability examined. The sharp diamond nanocone features were found to have bactericidal capabilities with the surface possessing the more varying cone dimension, nonuniform array, and decreased density, showing enhanced bactericidal ability over the more uniform, highly dense nanocone surface. Future research will focus on using the fabrication process to tailor surface nanotopographies on clinically relevant materials that promote both effective killing of a broader range of microorganisms and the desired mammalian cell response. This study serves to introduce a technology that may launch a new and innovative direction in the design of biomaterials with capacity to reduce the risk of medical device-associated infections. PMID:26992656

  4. A multi-electrode biomimetic electrolocation sensor

    Science.gov (United States)

    Mayekar, K.; Damalla, D.; Gottwald, M.; Bousack, H.; von der Emde, G.

    2012-04-01

    We present the concept of an active multi-electrode catheter inspired by the electroreceptive system of the weakly electric fish, Gnathonemus petersii. The skin of this fish exhibits numerous electroreceptor organs which are capable of sensing a self induced electrical field. Our sensor is composed of a sending electrode and sixteen receiving electrodes. The electrical field produced by the sending electrode was measured by the receiving electrodes and objects were detected by the perturbation of the electrical field they induce. The intended application of such a sensor is in coronary diagnostics, in particular in distinguishing various types of plaques, which are major causes of heart attack. For calibration of the sensor system, finite element modeling (FEM) was performed. To validate the model, experimental measurements were carried out with two different systems. The physical system was glass tubing with metal and plastic wall insertions as targets. For the control of the experiment and for data acquisition, the software LabView designed for 17 electrodes was used. Different parameters of the electric images were analyzed for the prediction of the electrical properties and size of the inserted targets in the tube. Comparisons of the voltage modulations predicted from the FEM model and the experiments showed a good correspondence. It can be concluded that this novel biomimetic method can be further developed for detailed investigations of atherosclerotic lesions. Finally, we discuss various design strategies to optimize the output of the sensor using different simulated models to enhance target recognition.

  5. Biomimetic visual detection based on insect neurobiology

    Science.gov (United States)

    O'Carroll, David C.

    2001-11-01

    With a visual system that accounts for as much as 30% of the lifted mass, flying insects such as dragonflies and hoverflies invest more in vision than any other animal. Impressive visual performance is subserved by a surprisingly simple visual system. In a typical insect eye, between 2,000 and 30,000 pixels in the image are analyzed by fewer than 200,000 neurons in underlying neural circuits. The combination of sophisticated visual processing with an approachable level of complexity has made the insect visual system a leading model for biomimetic approaches to computer vision. Much neurobiological research has focused on neural circuits used for detection of moving patterns (e.g. optical flow during flight) and moving targets (e.g. prey). Research from several labs has led to great advances in our understanding of the neural mechanisms involved, and has spawned neuromorphic hardware based on key processes identified in neurobiological experiments. Despite its attractions, the highly non-linear nature of several key stages in insect visual processing presents a challenge to understanding. I will describe examples of adaptive elements of neural circuits in the fly visual system which analyze the direction and velocity of wide-field optical flow patterns and the result of experiments that suggest that these non-linearities may contribute to robust responses to natural image motion.

  6. Sem analysis zirconia-ceramic adhesion interface

    Science.gov (United States)

    CARDELLI, P.; VERTUCCI, V.; MONTANI, M.; ARCURI, C.

    2015-01-01

    SUMMARY Objectives Modern dentistry increasingly tends to use materials aesthetically acceptable and biomimetic. Among these are zirconia and ceramics for several years, a combination that now has becoming synonym of aesthetic; however, what could be the real link between these two materials and especially its nature, remains a controversial topic debated in the literature. The aim of our study was to “underline” the type of bonding that could exist between these materials. Materials and methods To investigate the nature of this bond we used a SEM microscopy (Zeiss SUPRA 25). Different bilaminar specimens: “white” zirconia Zircodent® and ceramic “Noritake®”, after being tested with loading test in bending (three-point-bending) and FEM analysis, were analyzed by SEM. Fragments’ analysis in closeness of the fracture’s point has allowed us to be able to “see” if at large magnifications between these two materials, and without the use of linear, could exist a lasting bond and the possible type of failure that could incur. Results From our analysis of the specimens’ fragments analyzed after test Equipment, it is difficult to highlight a clear margin and no-adhesion zones between the two materials, although the analysis involving fragments adjacent to the fracture that has taken place at the time of Mechanical test Equipment. Conclusions According to our analysis and with all the clarification of the case, we can assume that you can obtain a long and lasting bond between the zirconia and ceramics. Agree to the data present in the literature, we can say that the type of bond varies according to the type of specimens and of course also the type of failure. In samples where the superstructure envelops the ceramic framework Zirconium we are in the presence of a cohesive failure, otherwise in a presence of adhesive failure. PMID:27555905

  7. Effective Length Design of Humanoid Robot Fingers Using Biomimetic Optimization

    Directory of Open Access Journals (Sweden)

    Byoung-Ho Kim

    2015-10-01

    Full Text Available In this study, we propose an effective design method for the phalangeal parameters and the total size of humanoid robot fingers based on a biomimetic optimization. For the optimization, an interphalangeal joint coordination parameter and the length constraints inherent in human fingers are considered from a biomimetic perspective. A reasonable grasp formulation is also taken into account from the viewpoint of power grasping, where the grasp space of a humanoid robot finger is importantly considered to determine the phalangeal length parameters. The usefulness of the devised biomimetic optimization method is shown through the design examples of various humanoid robot fingers. In fact, the optimization-based finger design method enables us to determine effectively the proper phalangeal size of humanoid robot fingers for human-like object handling tasks. In addition, we discuss its contribution to the structural configuration and coordinated motion of a humanoid robot finger, and address its practical availability in terms of effective finger design.

  8. Biomimetic Nanotechnology: A Powerful Means to address Global Challenges

    CERN Document Server

    Gebeshuber, Ille C

    2010-01-01

    Biomimetic nanotechnology is a prominent research area at the meeting place of life sciences with engineering and physics: it is a continuously growing field that deals with knowledge transfer from biology to nanotechnology. Biomimetic nanotechnology is a field that has the potential to substantially support successful mastering of major global challenges. The Millennium Project was commissioned by the United Nations Secretary-General in 2002 to develop a concrete action plan for the world to reverse the grinding poverty, hunger and disease affecting billions of people. It states 15 Global Challenges: sustainable development, water, population and resources, democratization, long-term perspectives, information technology, the rich-poor gap, health, capacity to decide, peace and conflict, status of women, transnational crime, energy, science and technology and global ethics. The possible contributions to master these challenges with the help of biomimetic nanotechnology will be discussed in detail.

  9. Tribological and electrochemical studies on biomimetic synovial fluids

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this study, tribological and electrochemical performances of the new biomimetic synovial fluids were studied according to different composition concentrations, including hyaluronic acid, albumin and alendronic acid sodium. By using Taguchi method, the composition contents of the biomimetic synovial fluids were designed. Items such as friction coefficient, mean scar diameter and viscosity were investigated via a four-ball tribo-tester, viscosity meter and optical microscope. Polarization studies were carried out to analyze the electrochemical behaviour of the fluids. Results showed that hyaluronic acid dominates the viscosity of the fluids. High albumin concentration will reduce friction, while increasing wear rate due to the electro-chemical effect. Alendronic acid sodium is found to reduce the biocorrosion of CoCrMo as well as provide better lubricating. In conclusion, biomimetic synovial fluids partially recover the functions of natural synovial fluids and provide good lubricating property.

  10. PEM Fuel Cells Redesign Using Biomimetic and TRIZ Design Methodologies

    Science.gov (United States)

    Fung, Keith Kin Kei

    Two formal design methodologies, biomimetic design and the Theory of Inventive Problem Solving, TRIZ, were applied to the redesign of a Proton Exchange Membrane (PEM) fuel cell. Proof of concept prototyping was performed on two of the concepts for water management. The liquid water collection with strategically placed wicks concept demonstrated the potential benefits for a fuel cell. Conversely, the periodic flow direction reversal concepts might cause a potential reduction water removal from a fuel cell. The causes of this water removal reduction remain unclear. In additional, three of the concepts generated with biomimetic design were further studied and demonstrated to stimulate more creative ideas in the thermal and water management of fuel cells. The biomimetic design and the TRIZ methodologies were successfully applied to fuel cells and provided different perspectives to the redesign of fuel cells. The methodologies should continue to be used to improve fuel cells.

  11. Handbook of adhesion

    CERN Document Server

    Packham, D E

    2006-01-01

    This second edition of the successful Handbook of Adhesion provides concise and authoritative articles covering many aspects of the science and technology associated with adhesion and adhesives. It is intended to fill a gap between the necessarily simplified treatment of the student textbook and the full and thorough treatment of the research monograph and review article. The articles are structured in such a way, with internal cross-referencing and external literature references, that the reader can build up a broader and deeper understanding, as their needs require.This second edition includ

  12. [Endothelial cell adhesion molecules].

    Science.gov (United States)

    Ivanov, A N; Norkin, I A; Puchin'ian, D M; Shirokov, V Iu; Zhdanova, O Iu

    2014-01-01

    The review presents current data concerning the functional role of endothelial cell adhesion molecules belonging to different structural families: integrins, selectins, cadherins, and the immunoglobulin super-family. In this manuscript the regulatory mechanisms and factors of adhesion molecules expression and distribution on the surface of endothelial cells are discussed. The data presented reveal the importance of adhesion molecules in the regulation of structural and functional state of endothelial cells in normal conditions and in pathology. Particular attention is paid to the importance of these molecules in the processes of physiological and pathological angiogenesis, regulation of permeability of the endothelial barrier and cell transmigration.

  13. Lactobacillus Adhesion to Mucus

    Directory of Open Access Journals (Sweden)

    Maxwell L. Van Tassell

    2011-05-01

    Full Text Available Mucus provides protective functions in the gastrointestinal tract and plays an important role in the adhesion of microorganisms to host surfaces. Mucin glycoproteins polymerize, forming a framework to which certain microbial populations can adhere, including probiotic Lactobacillus species. Numerous mechanisms for adhesion to mucus have been discovered in lactobacilli, including partially characterized mucus binding proteins. These mechanisms vary in importance with the in vitro models studied, which could significantly affect the perceived probiotic potential of the organisms. Understanding the nature of mucus-microbe interactions could be the key to elucidating the mechanisms of probiotic adhesion within the host.

  14. Preparation and in vitro evaluation of a biomimetic nanoscale calcium phosphate coating on a polyethylene terephthalate artificial ligament

    Science.gov (United States)

    CHEN, CHEN; LI, HONG; GUO, CHANGAN; CHEN, SHIYI

    2016-01-01

    In the present study, a polyethylene terephthalate (PET) artificial ligament was coated with an organic layer-by-layer (LBL) self-assembled template of chitosan and hyaluronic acid, and then incubated in a calcium phosphate (CaP) solution to prepare a biomimetic CaP coating. The surface characterization of the ligament was examined using scanning electron microscopy, atomic force microscopy and energy-dispersive X-ray spectroscopy. The effects of CaP coatings on the osteogenic activity of MC3T3 E1 mouse osteoblastic cells were investigated by evaluating their attachment, proliferation and the relative expression levels of alkaline phosphatase. The results revealed that the organic LBL template on the PET artificial ligament was effective for CaP apatite formation. Following incubation for 72 h, numerous nanoscale CaP apatites were deposited on the PET ligament fibers. In addition, the results of the in vitro culture of MC3T3-E1 mouse osteoblastic cells demonstrated that the CaP coating had a good biocompatibility for cell proliferation and adhesion, and the CaP-coated group had a significantly higher alkaline phosphatase activity compared with the uncoated control group after seven days of cell culture. Collectively, these results demonstrated that the biomimetic nanoscale CaP-coated PET artificial ligaments have potential in bone-tissue engineering. PMID:27347053

  15. Isotropic Versus Bipolar Functionalized Biomimetic Artificial Basement Membranes and Their Evaluation in Long-Term Human Cell Co-Culture.

    Science.gov (United States)

    Rossi, Angela; Wistlich, Laura; Heffels, Karl-Heinz; Walles, Heike; Groll, Jürgen

    2016-08-01

    In addition to dividing tissues into compartments, basement membranes are crucial as cell substrates and to regulate cellular behavior. The development of artificial basement membranes is indispensable for the ultimate formation of functional engineered tissues; however, pose a challenge due to their complex structure. Herein, biodegradable electrospun polyester meshes are presented, exhibiting isotropic or bipolar bioactivation as a biomimetic and biofunctional model of the natural basement membrane. In a one-step preparation process, reactive star-shaped prepolymer additives, which generate a hydrophilic fiber surface, are electrospun with cell-adhesion-mediating peptides, derived from major components of the basement membrane. Human skin cells adhere to the functionalized meshes, and long-term co-culture experiments confirm that the artificial basement membranes recapitulate and preserve tissue specific functions. Several layers of immortalized human keratinocytes grow on the membranes, differentiating toward the surface and expressing typical epithelial markers. Fibroblasts migrate into the reticular lamina mimicking part of the mesh. Both cells types begin to produce extracellular matrix proteins and to remodel the initial membrane. It is shown at the example of skin that the artificial basement membrane design provokes biomimetic responses of different cell types and can thus be used as basis for the future development of basement membrane containing tissues. PMID:27283510

  16. Characterization of the structure and composition of gecko adhesive setae.

    Science.gov (United States)

    Rizzo, N W; Gardner, K H; Walls, D J; Keiper-Hrynko, N M; Ganzke, T S; Hallahan, D L

    2006-06-22

    The ability of certain reptiles to adhere to vertical (and hang from horizontal) surfaces has been attributed to the presence of specialized adhesive setae on their feet. Structural and compositional studies of such adhesive setae will contribute significantly towards the design of biomimetic fibrillar adhesive materials. The results of electron microscopy analyses of the structure of such setae are presented, indicating their formation from aggregates of proteinaceous fibrils held together by a matrix and potentially surrounded by a limiting proteinaceous sheath. Microbeam X-ray diffraction analysis has shown conclusively that the only ordered protein constituent in these structures exhibits a diffraction pattern characteristic of beta-keratin. Raman microscopy of individual setae, however, clearly shows the presence of additional protein constituents, some of which may be identified as alpha-keratins. Electrophoretic analysis of solubilized setal proteins supports these conclusions, indicating the presence of a group of low-molecular-weight beta-keratins (14-20 kDa), together with alpha-keratins, and this interpretation is supported by immunological analyses.

  17. Mimicking mussel adhesion to improve interfacial properties in composites.

    Science.gov (United States)

    Hamming, L M; Fan, X W; Messersmith, P B; Brinson, L C

    2008-07-01

    The macroscale properties of polymer-matrix composites depend immensely on the quality of the interaction between the reinforcement phase and the bulk polymer. This work presents a method to improve the interfacial adhesion between metal-oxides and a polymer matrix by performing surface-initiated polymerization (SIP) by way of a biomimetic initiator. The initiator was modeled after 3,4-dihydroxy-L-phenylalanine (dopa), an amino acid that is highly concentrated in mussel foot adhesive proteins. Mechanical pull out tests of NiTi and Ti-6Al-4V wires from poly (methyl methacrylate) (PMMA) were performed to directly test the interfacial adhesion. These tests demonstrated improvements in maximum interfacial shear stress of 116% for SIP-modified NiTi wires and 60% for SIP-modified Ti-6Al-4V wires over unmodified specimens. Polymer chain growth from the metal oxides was validated using x-ray photoemission spectroscopy (XPS), ellipsometry, scanning electron microscopy (SEM), and contact angle analysis. PMID:19578545

  18. Desalination by biomimetic aquaporin membranes: Review of status and prospects

    DEFF Research Database (Denmark)

    Tang, C.Y.; Zhao, Y.; Wang, R.;

    2013-01-01

    Based on their unique combination of offering high water permeability and high solute rejection aquaporin proteins have attracted considerable interest over the last years as functional building blocks of biomimetic membranes for water desalination and reuse. The purpose of this review...... is to provide an overview of the properties of aquaporins, their preparation and characterization. We discuss the challenges in exploiting the remarkable properties of aquaporin proteins for membrane separation processes and we present various attempts to construct aquaporin in membranes for desalination......; including an overview of our own recent developments in aquaporin-based membranes. Finally we outline future prospects of aquaporin based biomimetic membrane for desalination and water reuse....

  19. Biomimetic actuators using electroactive polymers (EAP) as artificial muscles

    Science.gov (United States)

    Bar-Cohen, Yoseph

    2006-01-01

    Evolution has resolved many of nature's challenges leading to lasting solutions with maximal performance and effective use of resources. Nature's inventions have always inspired human achievements leading to effective materials, structures, tools, mechanisms, processes, algorithms, methods, systems and many other benefits. The field of mimicking nature is known as Biomimetics and one of its topics includes electroactive polymers that gain the moniker artificial muscles. Integrating EAP with embedded sensors, self-repair and many other capabilities that are used in composite materials can add greatly to the capability of smart biomimetic systems. Such development would enable fascinating possibilities potentially turning science fiction ideas into engineering reality.

  20. Leukocyte Adhesion Deficiency (LAD)

    Science.gov (United States)

    ... Content Marketing Share this: Main Content Area Leukocyte Adhesion Deficiency (LAD) LAD is an immune deficiency in ... are slow to heal also may have LAD. Treatment and Research Doctors prescribe antibiotics to prevent and ...

  1. Characterization and in vitro biological evaluation of mineral/osteogenic growth peptide nanocomposites synthesized biomimetically on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Cen; Kong, Xiangdong [Bio-X Center, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Zhang, Sheng-Min [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Lee, In-Seop, E-mail: inseop@yonsei.ac.kr [Bio-X Center, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Institute of Natural Sciences, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2015-04-15

    Graphical abstract: - Highlights: • Mineral/OGP nanocomposite layers were synthesized biomimetically on Ti substrates. • Incorporated OGP affected the morphology and ultimate structure of mineral. • Incorporated OGP improved the MSCs adhesion, proliferation, and ALP activity. - Abstract: Nanocomposite layers of mineral/osteogenic growth peptide (OGP) were synthesized on calcium phosphate coated titanium substrates by immersing in calcium-phosphate buffer solution containing OGP. Peptide incorporated mineral was characterized by determining quantity loaded, effects on mineral morphology and structure. Also, the biological activity was investigated by cell adhesion, proliferation assay, and measurement of alkaline phosphatase (ALP) activity. X-ray photoelectron spectroscopy (XPS) and micro-bicinchoninic acid (BCA) assay revealed that OGP was successfully incorporated with mineral and the amount was increased with immersion time. Incorporated OGP changed the mineral morphology from sharp plate-like shape to more rounded one, and the octacalcium phosphate structure of the mineral was gradually transformed into apatite. With confocal microscopy to examine the incorporation of fluorescently labeled peptide, OGP was evenly distributed throughout mineral layers. Mineral/OGP nanocomposites promoted cell adhesion and proliferation, and also increased ALP activity of mesenchymal stem cells (MSCs). Results presented here indicated that the mineral/OGP nanocomposites formed on titanium substrates had the potential for applications in dental implants.

  2. Management of adhesive capsulitis

    OpenAIRE

    Neviaser, Andrew

    2015-01-01

    Kristen L Stupay,1 Andrew S Neviaser2 1Tulane University School of Medicine, New Orleans, LA, USA; 2George Washington University Medical Faculty Associates, Washington, DC, USA Abstract: Adhesive capsulitis of the shoulder is a condition of capsular contracture that reduces both active and passive glenohumeral motion. The cause of adhesive capsulitis is not known but it is strongly associated with endocrine abnormalities such as diabetes. Diverse terminology and the absence of definitive cri...

  3. HYDRODYNAMIC BEHAVIOR OF AN UNDERWATER MOVING BODY AFTER WATER ENTRY

    Institute of Scientific and Technical Information of China (English)

    施红辉; 高见卓也

    2001-01-01

    An experimental study was conducted to investigate the vater entry phenomenon. A facility was designed to carry out the tests with the entry velocities of around 352 m/s. Visualization, pressure measurement, velocity measurement and underwater impact test were performed to investigate the hydroballistic behavior of the underwater moving body, the underwater flow field, the supercavitation,etc.. This study shows that the motion of a high-speed underwater body is strongly three-dimensional and chaotic. Furthermore, it is found that the distribution of the trajectory deflection of the underwater projectile depends on the depth of water. It is also found by measuring the deformation on a witness plate submerged in water,that the impact energy of an underwater projectile is reduced as it penetrates deeper into vater.

  4. Trajectory Simulation for Underwater Vehicle with Power-Lunched

    Institute of Scientific and Technical Information of China (English)

    Chaoqian Chen; Wei Cao; Cong Wang∗and Yingjie Wei

    2016-01-01

    The motion of combustion gas bubble produced by underwater ignition was developed based on Rayleigh⁃Plesset equation. Combining the bubble motion equation with the underwater launched vehicle motion equation in the longitudinal plane, a trajectory simulation model with power⁃launched was established. The hydrodynamic characteristics of underwater ignition at different depths and the trajectory analysis of the underwater vehicle with power⁃launched were given by simulation. The simulation results have a good agreement with experimental results, and show that the thrust peak caused by underwater ignition and the stable thrust both decrease slightly with the increase of the water depth, and the thrust peak will decline obviously by enlarging the initial radius of gas bubble; the thrust peak generated at the instant of ignition and the low⁃frequency oscillation of the stable thrust have no significant influence on the trajectory of underwater vehicle.

  5. Bioinspired pressure actuated adhesive system

    NARCIS (Netherlands)

    Paretkar, D.R.; Kamperman, M.M.G.; Schneider, A.S.; Martina, D.; Creton, C.; Arzt, E.

    2011-01-01

    We developed a dry synthetic adhesive system inspired by gecko feet adhesion that can switch reversibly from adhesion to non-adhesion with applied pressure as external stimulus. Micropatterned polydimethylsiloxane (PDMS) surfaces with pillars of 30 µm length and 10 µm diameter were fabricated using

  6. Visualizing underwater acoustic matched-field processing

    Science.gov (United States)

    Rosenblum, Lawrence; Kamgar-Parsi, Behzad; Karahalios, Margarida; Heitmeyer, Richard

    1991-06-01

    Matched-field processing is a new technique for processing ocean acoustic data measured by an array of hydrophones. It produces estimates of the location of sources of acoustic energy. This method differs from source localization techniques in other disciplines in that it uses the complex underwater acoustic environment to improve the accuracy of the source localization. An unexplored problem in matched-field processing has been to separate multiple sources within a matched-field ambiguity function. Underwater acoustic processing is one of many disciplines where a synthesis of computer graphics and image processing is producing new insight. The benefits of different volume visualization algorithms for matched-field display are discussed. The authors show how this led to a template matching scheme for identifying a source within the matched-field ambiguity function that can help move toward an automated source localization process.

  7. Ocean Research Enabled by Underwater Gliders

    Science.gov (United States)

    Rudnick, Daniel L.

    2016-01-01

    Underwater gliders are autonomous underwater vehicles that profile vertically by changing their buoyancy and use wings to move horizontally. Gliders are useful for sustained observation at relatively fine horizontal scales, especially to connect the coastal and open ocean. In this review, research topics are grouped by time and length scales. Large-scale topics addressed include the eastern and western boundary currents and the regional effects of climate variability. The accessibility of horizontal length scales of order 1 km allows investigation of mesoscale and submesoscale features such as fronts and eddies. Because the submesoscales dominate vertical fluxes in the ocean, gliders have found application in studies of biogeochemical processes. At the finest scales, gliders have been used to measure internal waves and turbulent dissipation. The review summarizes gliders' achievements to date and assesses their future in ocean observation.

  8. Detecting underwater improvised explosive threats (DUIET)

    Science.gov (United States)

    Feeley, Terry

    2010-04-01

    Improvised Explosive Devices (IEDs) have presented a major threat in the wars in Afghanistan and Iraq. These devices are powerful homemade land mines that can be small and easily hidden near roadsides. They are then remotely detonated when Coalition Forces pass by either singly or in convoys. Their rapid detection, classification and destruction is key to the safety of troops in the area. These land based bombs will have an analogue in the underwater theater especially in ports, lakes, rivers and streams. These devices may be used against Americans on American soil as an element of the global war on terrorism (GWOT) Rapid detection and classification of underwater improvised explosive devices (UIED) is critical to protecting innocent lives and maintaining the day to day flow of commerce. This paper will discuss a strategy and tool set to deal with this potential threat.

  9. Cellular Underwater Wireless Optical CDMA Network: Potentials and Challenges

    OpenAIRE

    Akhoundi, Farhad; Jamali, Mohammad Vahid; Banihassan, Navid; Beyranvand, Hamzeh; Minoofar, Amir; Salehi, Jawad A.

    2016-01-01

    Underwater wireless optical communications is an emerging solution to the expanding demand for broadband links in oceans and seas. In this paper, a cellular underwater wireless optical code division multiple-access (UW-OCDMA) network is proposed to provide broadband links for commercial and military applications. The optical orthogonal codes (OOC) are employed as signature codes of underwater mobile users. Fundamental key aspects of the network such as its backhaul architecture, its potential...

  10. Device for Underwater Laboratory Simulation of Unconfined Blast Waves

    OpenAIRE

    Courtney, Elijah; Courtney, Amy; Courtney, Michael

    2015-01-01

    Shock tubes simulate blast waves to study their effects in air under laboratory conditions; however, few experimental models exist for simulating underwater blast waves that are needed for facilitating experiments in underwater blast transmission, determining injury thresholds in marine animals, validating numerical models, and exploring mitigation strategies for explosive well removals. This method incorporates an oxy-acetylene driven underwater blast simulator which creates peak blast press...

  11. Study on Image Quality Improvement Methods for Underwater Imaging Systems

    OpenAIRE

    Lu, Huimin

    2014-01-01

    Underwater survey systems have numerous scientific or industrial applications in the fields of geology, biology, mining, and archeology. These application fields involve various tasks such as ecological studies, environmental damage assessment, and ancient prospection. During two decades, underwater imaging systems are mainly equipped by Underwater Vehicles (UV) for surveying in water or ocean. Challenges associated with obtaining visibility of objects have been difficult to overcome due to t...

  12. Balance Transmission Mechanism in Underwater Acoustic Sensor Networks

    OpenAIRE

    Jiabao Cao; Jinfeng Dou; Shunle Dong

    2015-01-01

    With the rapid development of underwater acoustic modem technology, underwater acoustic sensor networks (UWASNs) have more applications in long-term monitoring of the deployment area. In the underwater environment, the sensors are costly with limited energy. And acoustic communication medium poses new challenges, including high path loss, low bandwidth, and high energy consumption. Therefore, designing transmission mechanism to decrease energy consumption and to optimize the lifetime of UWASN...

  13. Scan matching SLAM in underwater environments

    OpenAIRE

    Mallios, Angelos; Ridao Rodríguez, Pere; Ribas Romagós, David; Hernàndez Bes, Emili

    2014-01-01

    This paper proposes a pose-based algorithm to solve the full simultaneous localization and mapping problem for autonomous underwater vehicle (AUV) navigating in unknown and possibly unstructured environments. The proposed method first estimates the local path traveled by the robot while forming the acoustic image (scan) with range data coming from a mono-beam rotating sonar head, providing position estimates for correcting the distortions that the vehicle motion produces in the scans. Then, c...

  14. Underwater SLAM in a marina environment

    OpenAIRE

    Ribas Romagós, David; Ridao Rodríguez, Pere; Tardós, Juan Domingo; Neira Parra, José

    2007-01-01

    This paper describes a navigation system for autonomous underwater vehicles (AUVs) in partially structured environments, such as dams, harbors, marinas or marine platforms. A mechanical scanning imaging sonar is used to obtain information about the location of planar structures present in such environments. A modified version of the Hough transform has been developed to extract line features, together with their uncertainty, from the continuous sonar dataflow. The information obtained is inco...

  15. Autonomy through SLAM for an Underwater Robot

    OpenAIRE

    Folkesson, John; Leonard, John,

    2011-01-01

    An autonomous underwater vehicle (AUV) is achieved that integrates state of the art simultaneous localization and mapping (SLAM) into the decision processes. This autonomy is used to carry out undersea target reacquisition missions that would otherwise be impossible with a low-cost platform. The AUV requires only simple sensors and operates without navigation equipment such as Doppler Velocity Log, inertial navigation or acoustic beacons. Demonstrations of the capability show that the vehicle...

  16. Feature tracking for underwater navigation using sonar

    OpenAIRE

    Folkesson, John; Leonard, John,; Leederkerken, Jacques; Williams, Rob

    2007-01-01

    Tracking sonar features in real time on an underwater robot is a challenging task. One reason is the low observability of the sonar in some directions. For example, using a blazed array sonar one observes range and the angle to the array axis with fair precision. The angle around the axis is poorly constrained. This situation is problematic for tracking features in world frame Cartesian coordinates as the error surfaces will not be ellipsoids. Thus Gaussian tracking of the features will not w...

  17. Modelling tunnel thrusters for autonomous underwater vehicles

    OpenAIRE

    Palmer, A.; Hearn, G.E.; Stevenson, P

    2008-01-01

    With 900 Autonomous Underwater Vehicles (AUVs) required over the next decade (Newman et al., 2007) existing survey-style AUVs need improved utilization factors. Additional control devices to extend operational capability need consideration together with the interchange between AUV control approaches. This paper considers supplementary through-body tunnel thruster control during the transition from survey operation to low-speed manoeuvring. Modified manoeuvring equations permit investigation o...

  18. Magnetic navigation and tracking of underwater vehicles

    Digital Repository Service at National Institute of Oceanography (India)

    Teixeira, F.C.; Pascoal, A.M.

    applications. Keywords: Navigation; tracking; magnetic methods; inverse problems; particle filters. 1. INTRODUCTION AND MAIN CONTRIBUTION OF THE PAPER The execution of long-range and long-term missions by robotic underwater vehicles in a fully autonomous mode... vehicles the capacity of executing long-range missions with minimum human intervention. Among the novel methods proposed, the terrain aided navigation (TAN) and the Simultaneous localization and mapping (SLAM) approaches have great potential...

  19. Femtosecond Laser Induced Underwater Superoleophobic Surfaces

    OpenAIRE

    Yong Jiale; Chen Feng; Yang Qing

    2015-01-01

    Femtosecond laser microfabrication has been recently utilized in interface science to modify the liquid wettability of solid surfaces. Silicon surface with hierarchical micro/nanostructure is fabricated by a femtosecond laser. Similar to the fish’s scales, the laser-induced surface shows superhydrophilicity in air and superoleophobicity underwater. The oil contact angles can reach up to 159.4 ± 1° for the 1,2-dichloroethane droplets in water. Besides, the surface exhibits ultralow oil-adhesio...

  20. Underwater sensor networks: applications, advances and challenges.

    Science.gov (United States)

    Heidemann, John; Stojanovic, Milica; Zorzi, Michele

    2012-01-13

    This paper examines the main approaches and challenges in the design and implementation of underwater wireless sensor networks. We summarize key applications and the main phenomena related to acoustic propagation, and discuss how they affect the design and operation of communication systems and networking protocols at various layers. We also provide an overview of communications hardware, testbeds and simulation tools available to the research community.

  1. Underwater noise generated by offshore pile driving

    OpenAIRE

    Tsouvalas, A.

    2015-01-01

    Anthropogenic noise emission in the marine environment has always been an environmental issue of serious concern. In particular, the noise generated during the installation of foundation piles is considered to be one of the most significant sources of underwater noise pollution. This is mainly attributed to the recent developments in the offshore wind industry. To meet the increasing demand for energy from renewable resources, a large number of offshore wind farms are planned to be constructe...

  2. Autonomous Underwater Vehicle „ABYSS“

    OpenAIRE

    Linke, Peter; Lackschewitz, Klas

    2016-01-01

    The Autonomous Underwater Vehicle (AUV) „ABYSS“ is a modular AUV designed to survey the ocean combining geophysical studies of the seafloor with oceanographic investigations of the overlying water column. The basic mission of ABYSS is deep-sea exploration, specifically in volcanically and tectonically active parts, such as mid-ocean ridges. With a maximum mission depth of 6000 meters, the AUV uses several technologies to map the seafloor accurately and determine its geological ...

  3. Autonomous Underwater Vehicle „ABYSS“

    OpenAIRE

    Linke, Peter; Lackschewitz, Klas

    2016-01-01

    The Autonomous Underwater Vehicle (AUV) „ABYSS“ is a modular AUV designed to survey the ocean combining geophysical studies of the seafloor with oceanographic investigations of the overlying water column. The basic mission of ABYSS is deep-sea exploration, specifically in volcanically and tectonically active parts, such as mid-ocean ridges. With a maximum mission depth of 6000 meters, the AUV uses several technologies to map the seafloor accurately and determine its geological structure with ...

  4. Biomimetic processing of oriented crystalline ceramic layers

    Energy Technology Data Exchange (ETDEWEB)

    Cesarano, J.; Shelnutt, J.A.

    1997-10-01

    The aim of this project was to develop the capabilities for Sandia to fabricate self assembled Langmuir-Blodgett (LB) films of various materials and to exploit their two-dimensional crystalline structure to promote the growth of oriented thin films of inorganic materials at room temperature. This includes the design and synthesis of Langmuir-active (amphiphilic) organic molecules with end groups offering high nucleation potential for various ceramics. A longer range goal is that of understanding the underlying principles, making it feasible to use the techniques presented in this report to fabricate unique oriented films of various materials for electronic, sensor, and membrane applications. Therefore, whenever possible, work completed in this report was completed with the intention of addressing the fundamental phenomena underlying the growth of crystalline, inorganic films on template layers of highly organized organic molecules. This problem was inspired by biological processes, which often produce exquisitely engineered structures via templated growth on polymeric layers. Seashells, for example, exhibit great toughness owing to their fine brick-and-mortar structure that results from templated growth of calcium carbonate on top of layers of ordered organic proteins. A key goal in this work, therefore, is to demonstrate a positive correlation between the order and orientation of the template layer and that of the crystalline ceramic material grown upon it. The work completed was comprised of several parallel efforts that encompassed the entire spectrum of biomimetic growth from solution. Studies were completed on seashells and the mechanisms of growth for calcium carbonate. Studies were completed on the characterization of LB films and the capability developed for the in-house fabrication of these films. Standard films of fatty acids were studied as well as novel polypeptides and porphyrins that were synthesized.

  5. Biomimetic catalysts responsive to specific chemical signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yan [Iowa State Univ., Ames, IA (United States)

    2015-03-04

    Part 1. Design of Biomimetic Catalysts Based on Amphiphilic Systems The overall objective of our research is to create biomimetic catalysts from amphiphilic molecules. More specifically, we aim to create supramolecular systems that can be used to control the microenvironment around a catalytic center in a biomimetic fashion and apply the learning to construct supramolecular catalysts with novel functions found in enzymatic catalysts. We have prepared synthetic molecules (i.e., foldamers) that could fold into helical structures with nanometer-sized internal hydrophilic cavities. Cavities of this size are typically observed only in the tertiary and quaternary structures of proteins but were formed in our foldamer prepared in just a few steps from the monomer. Similar to many proteins, our foldamers displayed cooperativity in the folding/unfolding equilibrium and followed a two-state conformational transition. In addition, their conformational change could be triggered by solvent polarity, pH, or presence of metal ions and certain organic molecules. We studied their environmentally dependent conformational changes in solutions, surfactant micelles, and lipid bilayer membranes. Unlike conventional rigid supramolecular host, a foldamer undergoes conformational change during guest binding. Our study in the molecular recognition of an oligocholate host yielded some extremely exciting results. Cooperativity between host conformation and host–guest interactions was found to “magnify” weak binding interactions. In other words, since binding affinity is determined by the overall change of free energy during the binding, guest-induced conformational change of the host, whether near or far from the binding site, affects the binding. This study has strong implications in catalysis because enzymes have been hypothesized to harvest similar intramolecular forces to strengthen their binding with the transition state of an enzyme-catalyzed reaction. The supramolecular and

  6. Underwater Noise Modelling of Wave Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Future large-scale implementation of wave energy converts (WECs) will introduce an anthropogenic activity in the ocean which may contribute to underwater noise. The Ocean houses several marine species with acoustic sensibility; consequently the potential impact of the underwater noise needs to be addressed. At present, there are no acoustic impact studies based on acquired data. The WEAM project (Wave Energy Acoustic Monitoring) aims at developing an underwater noise monitoring plan for WECs. The development of an acoustic monitoring plan must consider the sound propagation in the ocean, identify noise sources, understand the operational characteristics and select adequate instrumentation. Any monitoring strategy must involve in-situ measurements. However, the vast distances which sound travels within the ocean, can make in-situ measurements covering the entire area of interest, impracticable. This difficulty can be partially overcome through acoustic numerical modelling. This paper presents a synthetic study, on the application of acoustic forward modelling and the evaluation of the impact of noise produced by wave energy devices on marine mammals using criteria based on audiograms of dolphins, or other species. The idea is to illustrate the application of that methodology, and to show to what extent it allows for estimating distances of impacts due to acoustic noise.

  7. Lifetime Prolonging Algorithms for Underwater Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    GUO Zhong-wen; LI Zhi-wei; YU Lei

    2006-01-01

    Underwater acoustic modem technology has attained a level of maturity to support underwater acoustic sensor networks (UASNs) which are generally formed by acoustically connected sensor nodes and a surface station providing a link to an on-shore control center. While many applications require long-term monitoring of the deployment area, the battery-powered network nodes limit the lifetime of UASNs. Therefore, designing a UASN that minimizes the power consumption while maximizing lifetime becomes a very difficult task. In this paper, a method is proposed to determine the optimum number of clusters through combining an application-specific protocol architecture and underwater acoustic communication model so as to reduce the energy dissipation of UASNs. Deploying more sensor nodes which work alternately is another way to prolong the lifetime of UASNs. An algorithm is presented for selecting sensor nodes and putting them into operation in each round, ensuring the monitoring to the whole given area. The present results show that the algorithm can help prolong system lifetime remarkably when it is applied to other conventional approaches for sensor networks under the condition that the sensor node density is high.

  8. Computer simulation of underwater nuclear events

    International Nuclear Information System (INIS)

    This report describes the computer simulation of two underwater nuclear explosions, Operation Wigwam and a modern hypothetical explosion of greater yield. The computer simulations were done in spherical geometry with the LASNEX computer code. Comparison of the LASNEX calculation with Snay's analytical results and the Wigwam measurements shows that agreement in the shock pressure versus range in water is better than 5%. The results of the calculations are also consistent with the cube root scaling law for an underwater blast wave. The time constant of the wave front was determined from the wave profiles taken at several points. The LASNEX time-constant calculation and Snay's theoretical results agree to within 20%. A time-constant-versus-range relation empirically fitted by Snay is valid only within a limited range at low pressures, whereas a time-constant formula based on Sedov's similarity solution holds at very high pressures. This leaves the intermediate pressure range with neither an empirical nor a theoretical formula for the time constant. These one-dimensional simulations demonstrate applicability of the computer code to investigations of this nature, and justify the use of this technique for more complex two-dimensional problems, namely, surface effects on underwater nuclear explosions. 16 refs., 8 figs., 2 tabs

  9. Modeling and Control of Underwater Robotic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Schjoelberg, I:

    1996-12-31

    This doctoral thesis describes modeling and control of underwater vehicle-manipulator systems. The thesis also presents a model and a control scheme for a system consisting of a surface vessel connected to an underwater robotic system by means of a slender marine structure. The equations of motion of the underwater vehicle and manipulator are described and the system kinematics and properties presented. Feedback linearization technique is applied to the system and evaluated through a simulation study. Passivity-based controllers for vehicle and manipulator control are presented. Stability of the closed loop system is proved and simulation results are given. The equation of motion for lateral motion of a cable/riser system connected to a surface vessel at the top end and to a thruster at the bottom end is described and stability analysis and simulations are presented. The equations of motion in 3 degrees of freedom of the cable/riser, surface vessel and robotic system are given. Stability analysis of the total system with PD-controllers is presented. 47 refs., 32 figs., 7 tabs.

  10. Biosensor UUV payload for underwater detection

    Science.gov (United States)

    Kusterbeck, Anne W.; Charles, Paul T.; Melde, Brian J.; Trammell, Scott A.; Adams, André A.; Deschamps, Jeffrey R.

    2010-04-01

    Increased emphasis on maritime domain awareness and port security has led to the development of unmanned underwater vehicles (UUVs) capable of extended missions. These systems rely most frequently on well-developed side scan sonar and acoustic methods to locate potential targets. The Naval Research Laboratory (NRL) is developing biosensors for underwater explosives detection that complement acoustic sensors and can be used as UUV payloads to monitor areas for port and harbor security or in detection of underwater unexploded ordnance (UXO) and biochemical threats. The prototype sensor has recently been demonstrated to detect explosives in seawater at trace levels when run in a continuous sampling mode. To overcome ongoing issues with sample preparation and facilitate rapid detection at trace levels in a marine environment, we have been developing new mesoporous materials for in-line preconcentration of explosives and other small molecules, engineering microfluidic components to improve the signal, and testing alternative signal transduction methods. Additional work is being done to optimize the optical components and sensor response time. Highlights of these current studies and our ongoing efforts to integrate the biosensor with existing detection technologies to reduce false positives are described. In addition, we present the results of field tests that demonstrate the prototype biosensor performance as a UUV payload.

  11. 76 FR 52734 - Underwater Locating Devices (Acoustic) (Self-Powered)

    Science.gov (United States)

    2011-08-23

    ... Brazilian authorities but the flight data recorder and cockpit voice recorder were not recovered until April... for underwater locator beacons installed on flight recorders on airplanes performing public...

  12. A Non Parametric Estimation Based Underwater Target Classifier

    Directory of Open Access Journals (Sweden)

    Binesh T, Supriya M.H & P.R.Saseendran Pillai

    2011-11-01

    Full Text Available Underwater noise sources constitute a prominent class of input signal in most underwater signalprocessing systems. The problem of identification of noise sources in the ocean is of greatimportance because of its numerous practical applications. In this paper, a methodology ispresented for the detection and identification of underwater targets and noise sources based onnon parametric indicators. The proposed system utilizes Cepstral coefficient analysis and theKruskal-Wallis H statistic along with other statistical indicators like F-test statistic for the effectivedetection and classification of noise sources in the ocean. Simulation results for typicalunderwater noise data and the set of identified underwater targets are also presented in thispaper.

  13. Calibration Techniques for Accurate Measurements by Underwater Camera Systems.

    Science.gov (United States)

    Shortis, Mark

    2015-12-07

    Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems.

  14. Controllable dielectric and electrical performance of polymer composites with novel core/shell-structured conductive particles through biomimetic method

    International Nuclear Information System (INIS)

    Highlights: ► Conductive core/shell-structured particles were synthesized by biomimetic method. ► These particles with silica/poly(dopamine)/silver core and poly(dopamine) shell. ► Dielectric composites were prepared with resulted particles and silicone elastomer. ► The dielectric properties of the composites can be controlled by shell thickness. ► This biomimetic method is simple, nontoxic, efficient and easy to control. - Abstract: Novel silica/poly(dopamine)/silver (from inner to outer) (denoted as SiO2/PDA/Ag) conductive micro-particles were first synthesized by biomimetic poly(dopamine) coating. These micro-particles were then coated with a poly(dopamine) layer to form core/shell-structured particles, with silica/poly(dopamine)/silver core and poly(dopamine) shell (denoted as SiO2/PDA/Ag/PDA). This multilayer core/shell micro-particles were confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscope. Polymer composites were then prepared by mechanical blending of poly(dimethyl siloxane) and the core/shell-structured particles. It was found that the silver layer and the poly(dopamine) shell had good adhesion with substrate and they kept intact even under violent shearing stress during mechanical mixing. The effect of the thickness of outermost poly(dopamine) shell as well as the loading amount of this filler on the dielectric and electrical properties of the composites was further studied. The results showed that the dielectric constant, dielectric loss, and conductivity of the composites decreased with increasing shell thickness (10–53 nm) at the same loading level. And the maximal dielectric constant of composites was achieved in the composites filled with SiO2/PDA/Ag/PDA (with 10–15 nm PDA shell) particles, which was much larger than that of the composite filled with SiO2/PDA/Ag particles without insulative PDA shell. At the same time, the composites can change from

  15. Dry adhesives with sensing features

    Science.gov (United States)

    Krahn, J.; Menon, C.

    2013-08-01

    Geckos are capable of detecting detachment of their feet. Inspired by this basic observation, a novel functional dry adhesive is proposed, which can be used to measure the instantaneous forces and torques acting on an adhesive pad. Such a novel sensing dry adhesive could potentially be used by climbing robots to quickly realize and respond appropriately to catastrophic detachment conditions. The proposed torque and force sensing dry adhesive was fabricated by mixing Carbon Black (CB) and Polydimethylsiloxane (PDMS) to form a functionalized adhesive with mushroom caps. The addition of CB to PDMS resulted in conductive PDMS which, when under compression, tension or torque, resulted in a change in the resistance across the adhesive patch terminals. The proposed design of the functionalized dry adhesive enables distinguishing an applied torque from a compressive force in a single adhesive pad. A model based on beam theory was used to predict the change in resistance across the terminals as either a torque or compressive force was applied to the adhesive patch. Under a compressive force, the sensing dry adhesive was capable of measuring compression stresses from 0.11 Pa to 20.9 kPa. The torque measured by the adhesive patch ranged from 2.6 to 10 mN m, at which point the dry adhesives became detached. The adhesive strength was 1.75 kPa under an applied preload of 1.65 kPa for an adhesive patch with an adhesive contact area of 7.07 cm2.

  16. Importance of loading and unloading procedures for gecko-inspired controllable adhesives.

    Science.gov (United States)

    Tamelier, John; Chary, Sathya; Turner, Kimberly L

    2013-08-27

    The importance of loading and unloading procedures has been shown in a variety of different methods for biological dry adhesives, such as the fibers on the feet of the Tokay gecko, but biomimetic dry adhesives have yet to be explored in a similar manner. To date, little work has systematically varied multiple parameters to discern the influence of the testing procedure, and the effect of the approach angle remains uncertain. In this study, a synthetic adhesive is moved in 13 individual approach and retraction angles relative to a flat substrate as well as 9 different shear lengths to discern how loading and unloading procedures influence the preload, adhesion, and shear/friction forces supported. The synthetic adhesive, composed of vertical 10 μm diameter semicircular poly(dimethylsiloxane) fibers, is tested against a 4 mm diameter flat glass puck on a home-built microtribometer using both vertical approach and retraction tests and angled approach and retraction tests. The results show that near maximum adhesion and friction can be obtained for most approach and retraction angles, provided that a sufficient shear length is performed. The results also show that the reaction forces during adhesive placement can be significantly reduced by using specific approach angles, resulting for the vertical fibers in a 38-fold increase in the ratio of adhesion force to preload force, μ', when compared to that when using a vertical approach. These results can be of use to those currently researching gecko-inspired adhesives when designing their testing procedures and control algorithms for climbing and perching robots.

  17. Bio-Mimetic Sensors Based on Molecularly Imprinted Membranes

    Directory of Open Access Journals (Sweden)

    Catia Algieri

    2014-07-01

    Full Text Available An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported.

  18. Hierarcially biomimetic bone materials: from nanometer to millimeter

    Institute of Scientific and Technical Information of China (English)

    ZHANG W.; CUI F. Z.; LIAO S. S.

    2001-01-01

    @@ The bone composite was produced by biomimetic synthesis. It shows some features of natural bone in both composition and microstructure. And the collagen moleculars and the nano-crystal hydroxyapatite assemble into ultrastructure similar to natural bone. It possesses porous structure with porosity from 100μm to 500μm after mixed with PLA (poly lactic acid).

  19. An efficient biomimetic coating methodology for a prosthetic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Adawy, Alaa, E-mail: a.adawy@science.ru.nl [Physics Department, Faculty of Science, Ain Shams University, Abbassia, Cairo (Egypt); Abdel-Fattah, Wafa I. [Biomaterials Department, National Research Centre, Giza (Egypt)

    2013-04-01

    The combination of the load-bearing metallic implants with the bioactive materials in the design of synthetic implants is an important aspect in the biomaterials research. Biomimetic coating of bioinert alloys with calcium phosphate phases provides a good alternative to the prerequisite for the continual replacement of implants because of the failure of bone-implant integration. We attempted to accelerate the biomimetic coating process of stainless steel alloy (316L) with biomimetic apatite. In addition, we investigated the incorporation of functioning minerals such as strontianite and smithsonite into the deposited layer. In order to develop a highly mature apatite coating, our method requires soaking of the pre-treated alloy in highly concentrated synthetic body fluid for only few hours. Surface characterizations were performed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). Also, the deposited apatitic layers were analysed by powder diffraction X-ray analysis (XRD). 316L surface showed the growth of highly crystalline, low carbonated hydroxyapatite, after only 6 h of the whole soaking process. Highlights: ► The manuscript describes a fast and efficient biomimetic coating methodology. ► This methodology can be used for metallic implants. ► 316L was coated with crystalline hydroxyapatite. ► Addition of strontium and zinc lead to the deposition of brushite. ► Coating of all synthetic solutions is highly crystalline.

  20. Biomimetic flavin-catalysed reactions for organic synthesis.

    Science.gov (United States)

    Iida, H; Imada, Y; Murahashi, S-I

    2015-07-28

    Using simple riboflavin related compounds as biomimetic catalysts, catalytic oxidation of various substrates with hydrogen peroxide or molecular oxygen can be performed selectively under mild conditions. The principle of these reactions is fundamental and will provide a wide scope for environmentally benign future practical methods.

  1. Design and Implementation of a Modular Biomimetic Infochemical Communication System

    NARCIS (Netherlands)

    Rácz, Z.; Cole, M.; Gardner, J.W.; Chowdhury, M.F.; Bula, W.P.; Gardeniers, J.G.E.; Karout, S.; Capurro, A.; Pearce, T.C.

    2013-01-01

    We describe here the design and implementation of a novel biomimetic infochemical communication system that employs airborne molecules alone to communicate over space and time. The system involves the design and fabrication of a microsystem capable of producing and releasing a precise mix of biosynt

  2. A biomimetic tactile sensing system based on polyvinylidene fluoride film

    Science.gov (United States)

    Xin, Yi; Tian, Hongying; Guo, Chao; Li, Xiang; Sun, Hongshuai; Wang, Peiyuan; Qian, Chenghui; Wang, Shuhong; Wang, Cheng

    2016-02-01

    Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensing material due to its outstanding properties such as biocompatibility, high thermal stability, good chemical resistance, high piezo-, pyro- and ferro-electric properties. This paper reports on the design, test, and analysis of a biomimetic tactile sensor based on PVDF film. This sensor consists of a PVDF film with aluminum electrodes, a pair of insulating layers, and a "handprint" friction layer with a copper foil. It is designed for easy fabrication and high reliability in outputting signals. In bionics, the fingerprint of the glabrous skin plays an important role during object handling. Therefore, in order to enhance friction and to provide better manipulation, the ridges of the fingertips were introduced into the design of the proposed tactile sensor. And, a basic experimental study on the selection of the high sensitivity fingerprint type for the biomimetic sensor was performed. In addition, we proposed a texture distinguish experiment to verify the sensor sensitivity. The experiment's results show that the novel biomimetic sensor is effective in discriminating object surface characteristics. Furthermore, an efficient visual application program (LabVIEW) and a quantitative evaluation method were proposed for the verification of the biomimetic sensor. The proposed tactile sensor shows great potential for contact force and slip measurements.

  3. Case Study in Biomimetic Design: Handling and Assembly of Microparts

    DEFF Research Database (Denmark)

    Shu, Li; Hansen, Hans Nørgaard; Gegeckaite, Asta;

    2006-01-01

    This paper describes the application of the biomimetic design process to the development of automated gripping devices for microparts. Handling and assembly of micromechanical parts is complicated by size effects that occur when part dimensions are scaled down. A common complication involves...

  4. Diffraction from relief gratings on a biomimetic elastomer cast

    International Nuclear Information System (INIS)

    Biomimetic optical elements combine the optimized designs of nature with the versatility of materials engineering. We employ a beetle carapace as the template for fabricating relief gratings on an elastomer substrate. Biological surface features are successfully replicated by a direct casting procedure. Far-field diffraction effects are discussed in terms of the Fraunhofer approximation in Fourier space.

  5. 3D Modelling of Biological Systems for Biomimetics

    Institute of Scientific and Technical Information of China (English)

    Shujun Zhang; Kevin Hapeshi; Ashok K. Bhattacharya

    2004-01-01

    With the advanced development of computer-based enabling technologies, many engineering, medical, biology,chemistry, physics and food science etc have developed to the unprecedented levels, which lead to many research and development interests in various multi-discipline areas. Among them, biomimetics is one of the most promising and attractive branches of study. Biomimetics is a branch of study that uses biological systems as a model to develop synthetic systems.To learn from nature, one of the fundamental issues is to understand the natural systems such animals, insects, plants and human beings etc. The geometrical characterization and representation of natural systems is an important fundamental work for biomimetics research. 3D modeling plays a key role in the geometrical characterization and representation, especially in computer graphical visualization. This paper firstly presents the typical procedure of 3D modelling methods and then reviews the previous work of 3D geometrical modelling techniques and systems developed for industrial, medical and animation applications. Especially the paper discusses the problems associated with the existing techniques and systems when they are applied to 3D modelling of biological systems. Based upon the discussions, the paper proposes some areas of research interests in 3D modelling of biological systems and for Biomimetics.

  6. A Laboratory Exercise to Introduce Inorganic Biomimetic Compounds.

    Science.gov (United States)

    Baird, Donald M.

    1985-01-01

    Biomimetic chemistry is concerned with the synthesis of small, molecular weight molecules which mimic the properties of metal-containing sites within certain biologically significant species. A series of experiments for an advanced undergraduate laboratory is described as a way to introduce this area into the chemistry curriculum. (JN)

  7. Controlling Underwater Robots with Electronic Nervous Systems

    Directory of Open Access Journals (Sweden)

    Joseph Ayers

    2010-01-01

    Full Text Available We are developing robot controllers based on biomimetic design principles. The goal is to realise the adaptive capabilities of the animal models in natural environments. We report feasibility studies of a hybrid architecture that instantiates a command and coordinating level with computed discrete-time map-based (DTM neuronal networks and the central pattern generators with analogue VLSI (Very Large Scale Integration electronic neuron (aVLSI networks. DTM networks are realised using neurons based on a 1-D or 2-D Map with two additional parameters that define silent, spiking and bursting regimes. Electronic neurons (ENs based on Hindmarsh–Rose (HR dynamics can be instantiated in analogue VLSI and exhibit similar behaviour to those based on discrete components. We have constructed locomotor central pattern generators (CPGs with aVLSI networks that can be modulated to select different behaviours on the basis of selective command input. The two technologies can be fused by interfacing the signals from the DTM circuits directly to the aVLSI CPGs. Using DTMs, we have been able to simulate complex sensory fusion for rheotaxic behaviour based on both hydrodynamic and optical flow senses. We will illustrate aspects of controllers for ambulatory biomimetic robots. These studies indicate that it is feasible to fabricate an electronic nervous system controller integrating both aVLSI CPGs and layered DTM exteroceptive reflexes.

  8. Magnetic field switchable dry adhesives.

    Science.gov (United States)

    Krahn, Jeffrey; Bovero, Enrico; Menon, Carlo

    2015-02-01

    A magnetic field controllable dry adhesive device is manufactured. The normal adhesion force can be increased or decreased depending on the presence of an applied magnetic field. If the magnetic field is present during the entire normal adhesion test cycle which includes both applying a preloading force and measuring the pulloff pressure, a decrease in adhesion is observed when compared to when there is no applied magnetic field. Similarly, if the magnetic field is present only during the preload portion of the normal adhesion test cycle, a decrease in adhesion is observed because of an increased stiffness of the magnetically controlled dry adhesive device. When the applied magnetic field is present during only the pulloff portion of the normal adhesion test cycle, either an increase or a decrease in normal adhesion is observed depending on the direction of the applied magnetic field.

  9. Adhesion in hydrogel contacts

    Science.gov (United States)

    Torres, J. R.; Jay, G. D.; Kim, K.-S.; Bothun, G. D.

    2016-05-01

    A generalized thermomechanical model for adhesion was developed to elucidate the mechanisms of dissipation within the viscoelastic bulk of a hyperelastic hydrogel. Results show that in addition to the expected energy release rate of interface formation, as well as the viscous flow dissipation, the bulk composition exhibits dissipation due to phase inhomogeneity morphological changes. The mixing thermodynamics of the matrix and solvent determines the dynamics of the phase inhomogeneities, which can enhance or disrupt adhesion. The model also accounts for the time-dependent behaviour. A parameter is proposed to discern the dominant dissipation mechanism in hydrogel contact detachment.

  10. Oxygen-plasma-modified biomimetic nanofibrous scaffolds for enhanced compatibility of cardiovascular implants

    Directory of Open Access Journals (Sweden)

    Anna Maria Pappa

    2015-01-01

    Full Text Available Electrospun nanofibrous scaffolds have been extensively used in several biomedical applications for tissue engineering due to their morphological resemblance to the extracellular matrix (ECM. Especially, there is a need for the cardiovascular implants to exhibit a nanostructured surface that mimics the native endothelium in order to promote endothelialization and to reduce the complications of thrombosis and implant failure. Thus, we herein fabricated poly-ε-caprolactone (PCL electrospun nanofibrous scaffolds, to serve as coatings for cardiovascular implants and guide tissue regeneration. Oxygen plasma treatment was applied in order to modify the surface chemistry of the scaffold and its effect on cell attachment and growth was evaluated. The conditions of the surface modification were properly adjusted in order to define those conditions of the treatment that result in surfaces favorable for cell growth, while maintaining morphological integrity and mechanical behavior. Goniometry (contact angle measurements, scanning electron microscopy (SEM, atomic force microscopy (AFM, and X-ray photoelectron spectroscopy (XPS measurements were used to evaluate the morphological and chemical changes induced by the plasma treatment. Moreover, depth-sensing nanoindentation was performed to study the resistance of the plasma-treated scaffolds to plastic deformation. Lastly, the cell studies indicated that all scaffolds were cytocompatible, with the plasma-treated ones expressing a more pronounced cell viability and adhesion. All the above findings demonstrate the great potential of these biomimetic tissue-engineering constructs as efficient coatings for enhanced compatibility of cardiovascular implants.

  11. Tuning 3D topography on biomimetic surface for efficient self-cleaning and microfluidic manipulation

    International Nuclear Information System (INIS)

    Currently, micro-/nanotopography on polymeric replica is generally limited to 2D when a mechanical demolding approach is applied. In this work, one-step replication of bio-inspired 3D topography is achieved using microinjection compression molding with novel dual-layer molds. Using a proposed flexible template, the replica topography and wettability are highly tunable during molding. Moreover, dual-scale topography on the mold is developed by coating the micropatterned insert with submicron silica particles. Contact angle and roll-off angle measurements indicate the lotus leaf, rose petal and rice leaf effects on biomimetic surfaces. Among the three kinds of surfaces, the petal-inspired surface possesses the superior performance in self-cleaning submicron contaminants and mechanical robustness, which is highly correlated to the low roughness-induced adhesive superhydrophobicity and the absence of fragile submicron-/nanostructure, respectively. Furthermore, a multi-layer mold structure is proposed for fabricating the open microfluidic devices. The embedment of the hydrophilic and hydrophobic silica particles in the microstructured open channel and the hydrophobic silica particles in the background area during replication renders the wettability contrast sharp, realizing the self-driven flow of microfluid confined within the open microchannel. (paper)

  12. Biomimetic apatite-coated porous PVA scaffolds promote the growth of breast cancer cells

    International Nuclear Information System (INIS)

    Recapitulating the native environment of bone tissue is essential to develop in vitro models of breast cancer bone metastasis. The bone is a composite material consisting of organic matrix and inorganic mineral phase, primarily hydroxyapatite. In this study, we report the mineralization of porous poly vinyl alcohol (PVA) scaffolds upon incubation in modified Hanks' Balanced Salt Solution (HBSS) for 14 days. Scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction analysis revealed that the deposited minerals have composition similar to hydroxyapatite. The study demonstrated that the rate of nucleation and growth of minerals was faster on surfaces of less porous scaffolds. However, upon prolonged incubation, formation of mineral layer was observed on the surface of all the scaffolds. In addition, the study also demonstrated that 3D mineralization only occurred for scaffolds with highly interconnected porous networks. The mineralization of the scaffolds promoted the adsorption of serum proteins and consequently, the adhesion and proliferation of breast cancer cells. - Highlights: • Porous PVA scaffolds fabricated via mechanical agitation followed by freeze-drying. • Mineralization of the scaffold was carried out by utilizing biomimetic approach. • Mineralization resulted in increased protein adsorption on the scaffold. • Increased breast cancer cell growth was observed on mineralized scaffolds

  13. A biomimetic nano hybrid coating based on the lotus effect and its anti-biofouling behaviors

    Science.gov (United States)

    Li, Jiang; Wang, Guoqing; Meng, Qinghua; Ding, Chunhua; Jiang, Hong; Fang, Yongzeng

    2014-10-01

    To develop an environmentally friendly anti-biofouling coating in virtue of bionics, a block copolymer containing fluorine (Coplm_F) of low surface energy was prepared by copolymerization. The Ag-loaded mesoporous silica (Ag@SBA) acting as a controlled-release antifoulant was prepared from the mesoporous silica (SBA-15). The nano hybrid coating (Ag@SBA/Coplm_F) composing of the Coplm_F and Ag@SBA was to biomimetically simulate the lotus microstructure. The concentration of fluorine element on surface was analyzed by the energy dispersive spectroscopy (EDS) and found rising to 1.45% after hybridation, which could be explained by the driving effect of SBA-15 via the hydrogen bond. This nanoscale morphology of the hybrid coating was measured and found highly semblable to the microstructure of the lotus surface. The contact angle was determined as 151° which confirmed the superhydrophobicity and lotus effect. The adhesion behaviors of Pseudomonas fluorescens, Diatoms, and Chlorella on the surface of the nano hybrid coating (Ag@SBA/Coplm_F) were studied and good effects of anti-biofouling were observed.

  14. Biomimetic apatite-coated porous PVA scaffolds promote the growth of breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Mao; Mohanty, Pravansu; Ghosh, Gargi, E-mail: gargi@umich.edu

    2014-11-01

    Recapitulating the native environment of bone tissue is essential to develop in vitro models of breast cancer bone metastasis. The bone is a composite material consisting of organic matrix and inorganic mineral phase, primarily hydroxyapatite. In this study, we report the mineralization of porous poly vinyl alcohol (PVA) scaffolds upon incubation in modified Hanks' Balanced Salt Solution (HBSS) for 14 days. Scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction analysis revealed that the deposited minerals have composition similar to hydroxyapatite. The study demonstrated that the rate of nucleation and growth of minerals was faster on surfaces of less porous scaffolds. However, upon prolonged incubation, formation of mineral layer was observed on the surface of all the scaffolds. In addition, the study also demonstrated that 3D mineralization only occurred for scaffolds with highly interconnected porous networks. The mineralization of the scaffolds promoted the adsorption of serum proteins and consequently, the adhesion and proliferation of breast cancer cells. - Highlights: • Porous PVA scaffolds fabricated via mechanical agitation followed by freeze-drying. • Mineralization of the scaffold was carried out by utilizing biomimetic approach. • Mineralization resulted in increased protein adsorption on the scaffold. • Increased breast cancer cell growth was observed on mineralized scaffolds.

  15. Underwater shock response analysis of a floating vessel

    NARCIS (Netherlands)

    Aanhold, J.E. van; Lemmen, P.P.M.

    1996-01-01

    The response of a surface vessel to underwater shock has been calculated using an explicit finite element analysis. The analysis model is two-dimensional and contains the floating steel structure, a large surrounding water volume and the free surface. The underwater shock is applied in the form of a

  16. Underwater communication. FOA-STU project 4: Maritime technology

    Science.gov (United States)

    Goetherstroem, L.; Kleman, B.; Lindquist, R.; Pentelius, T.

    1980-04-01

    Technological forecasts for underwater communication by acoustical, optical, or radio techniques are summarized. Results on transmission by the various means were evaluated under different hypotheses for the aqueous milieu. Technological possibilities, the need for underwater communications in assorted applications, and a practical assessment of the potential for realization are considered. Conclusions lead to a proposal for a series of development projects.

  17. Underwater Acoustic Image Transmission System Based on DSP

    Institute of Scientific and Technical Information of China (English)

    Cheng En; Xu Ru

    2002-01-01

    The underwater acoustic image transmission system based on the high-speed DSP device TMS320C549 has been studied. We use Goertzel algorithm for source decoding and MFSK for modulation. Turbo code is used for channel coding and decoding. The purpose is to implement underwater video image data transmission.

  18. Characterization of ships as sources of underwater noise

    NARCIS (Netherlands)

    Jong, C.A.F.

    2009-01-01

    There is a growing interest in the possible impact of anthropogenic underwater noise on marine life [1]. One of the concerns is the increasing contribution of shipping noise, with the growing number and size of commercial ships. Traditionally, underwater radiated noise control was only of interest f

  19. Preliminary OFDM based acoustic communication for underwater sensor networks synchronization

    OpenAIRE

    Pallarés Valls, Oriol; Sarriá Gandul, David; Viñolo Monzoncillo, Carlos; Río Fernandez, Joaquín del; Manuel Lázaro, Antonio

    2013-01-01

    This work presents a first approach to wireless underwater sensor networks UWSN time synchronization, using OFDM (Orthogonal Frequency Division Multiplexing) acoustic communication and time reference served by a synchronization protocol. This synchronization and type of modulation allows getting a low drift clock on each sensor, on a high efficiency underwater communication network. Peer Reviewed

  20. Remarks on the observability of single beacon underwater navigation

    DEFF Research Database (Denmark)

    Jouffroy, Jerome; Ross, Andrew

    This paper contributes a simple and intuitive result in the analysis of underwater navigation using a single ranging beacon. This analysis should help with the design of small and lightweight underwater vehicles by reducing the amount of instrumentation required for accurate navigation. The concept...

  1. The WODA guidance paper on underwater sound from dredging (abstract)

    NARCIS (Netherlands)

    Thomsen, F.; Borsani, F.; Clarke, D.; Jong, C.A.F. de; Witt, P. de; Holtkamp, M.; Goethals, F.; San Martin, E.; Spadaro, P.; Raalte, G. van; Jensen, A.

    2013-01-01

    The World Organisation of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) was established to provide a guidance paper on dredging sound, impact on aquatic biota and advice on unde

  2. Self-localization for underwater inspection robot in reactor systems

    International Nuclear Information System (INIS)

    An underwater inspection robot has been needed for preventive maintenance in a nuclear power plant. This paper deals with a self-localization method for the underwater inspection robot. In this method, the position and the orientation of the robot are estimated by using the particle filter. For showing the effectiveness of the proposed method, an experiment with real robot is demonstrated. (author)

  3. Mexican Underwater Archaeology and Some of its Challenges and Solutions

    Directory of Open Access Journals (Sweden)

    Pilar Luna Erreguerena

    2013-10-01

    Full Text Available In response to Carver’s lead article, I’d like to highlight an easily overlooked aspect of archaeology: underwater archaeology. I will offer some examples and experiences from Mexico, which will perhaps resonate in other cities and nations around the world with a rich underwater cultural heritage.

  4. Underwater shock response analysis of a floating vessel

    NARCIS (Netherlands)

    Aanhold, J.E. van; Meijer, G.J.; Lemmen, P.P.M.

    1998-01-01

    The response of a surface vessel to underwater shock has been calculated using an explicit finite element analysis. The analysis model is two-dimensional and contains the floating steel structure, a large surrounding water volume and the free surface. The underwater shock is applied in the form ot a

  5. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives

    OpenAIRE

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-01-01

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structur...

  6. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks †

    Science.gov (United States)

    Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong

    2016-01-01

    The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones. PMID:27213379

  7. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks.

    Science.gov (United States)

    Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong

    2016-01-01

    The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones.

  8. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Qiu Wang

    2016-05-01

    Full Text Available The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed and different hydrophones (isotropic hydrophones and array hydrophones in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones.

  9. Design and implementation of an underwater sound recording device

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Jayson J.; Myers, Joshua R.; Carlson, Thomas J.; Deng, Zhiqun; Rohrer, John S.; Caviggia, Kurt A.

    2011-09-19

    The purpose of this study was to design and build two versions of an underwater sound recording device. The device designed is referred to as the Underwater Sound Recorder (USR), which can be connected to one or two hydrophones or other underwater sound sensors. The URS contains a 26 dB preamplifier and a user selectable gain that permits additional amplification of input to the system from 26 dB to 46 dB. Signals within the frequency range up to 15 kHz may be recorded using the USR. Examples of USR applications are monitoring underwater processes that have the potential to create large pressure waves that could potentially harm fish or other aquatic life, such as underwater explosions or pile driving. Additional applications are recording sound generated by vessels or the vocalizations of some marine mammals, such as the calls from many species of whales.

  10. The design of underwater hull-cleaning robot

    Institute of Scientific and Technical Information of China (English)

    YUAN Fu-cai; GUO Li-bin; MENG Qing-xin; LIU Fu-qiang

    2004-01-01

    The research on underwater ship-hull cleaning robot was conducted on the purpose of realizing the automation of cleaning underwater ship hull so that service life of ship will be prolonged and ship speed will raised. Moreover, fuel consumption and the work intensity of divers will be reduced. In this paper, the current situation and the latest technology in China and abroad were analyzed;meanwhile, the typical characteristics of the underwater cleaning robot were introduced. According to the work principle of the underwater cleaning robot, the emphasis was put on the analysis and study of permanent-magnetic absorption, magnetic wheel, airproof and anticorrosion, underwater cleaning equipment and control system. The robot is easy in rotation and simple in control.

  11. Shock initiated instabilities in underwater cylindrical structures

    Science.gov (United States)

    Gupta, Sachin; Matos, Helio; LeBlanc, James M.; Shukla, Arun

    2016-10-01

    An experimental investigation to understand the mechanisms of dynamic buckling instability in cylindrical structures due to underwater explosive loadings is conducted. In particular, the effects of initial hydrostatic pressure coupled with a dynamic pressure pulse on the stability of metallic cylindrical shells are evaluated. The experiments are conducted at varying initial hydrostatic pressures, below the critical buckling pressure, to estimate the threshold after which dynamic buckling will initiate. The transient underwater full-field deformations of the structures during shock wave loading are captured using high-speed stereo photography coupled with modified 3-D Digital Image Correlation (DIC) technique. Experimental results show that increasing initial hydrostatic pressure decreases the natural vibration frequency of the structure indicating loss in structural stiffness. DIC measurements reveal that the initial structural excitations primarily consist of axisymmetric vibrations due to symmetrical shock wave loading in the experiments. Following their decay after a few longitudinal reverberations, the primary mode of vibration evolves which continues throughout later in time. At the initial hydrostatic pressures below the threshold value, these vibrations are stable in nature. The analytical solutions for the vibration frequency and the transient response of cylindrical shell are discussed in the article by accounting for both (1) the added mass effect of the surrounding water and (2) the effect of initial stress on the shell imposed by the hydrostatic pressure. The analytical solutions match reasonably well with the experimental vibration frequencies. Later, the transient response of a cylindrical shell subjected to a general underwater pressure wave loading is derived which leads to the analytical prediction of dynamic stability.

  12. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives.

    Science.gov (United States)

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-11-01

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structures. In this study, we demonstrate that these adhesives are capable of switching adhesion not only in ambient air conditions but also in vacuum. Our bioinspired patterned adhesive with an area of 1 cm(2) provided an adhesion force of 2.6 N ± 0.2 N in air, which was reduced to 1.9 N ± 0.2 N if measured in vacuum. Detachment was induced by buckling of the structures due to a high compressive preload and occurred, independent of air pressure, at approximately 0.9 N ± 0.1 N. The switch in adhesion was observed at a compressive preload between 5.6 and 6.0 N and was independent of air pressure. The difference between maximum adhesion force and adhesion force after buckling gives a reasonable window of operation for pick and place processes. High reversibility of the switching behavior is shown over 50 cycles in air and in vacuum, making the bioinspired switchable adhesive applicable for handling operations of fragile objects. PMID:26457864

  13. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives.

    Science.gov (United States)

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-11-01

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structures. In this study, we demonstrate that these adhesives are capable of switching adhesion not only in ambient air conditions but also in vacuum. Our bioinspired patterned adhesive with an area of 1 cm(2) provided an adhesion force of 2.6 N ± 0.2 N in air, which was reduced to 1.9 N ± 0.2 N if measured in vacuum. Detachment was induced by buckling of the structures due to a high compressive preload and occurred, independent of air pressure, at approximately 0.9 N ± 0.1 N. The switch in adhesion was observed at a compressive preload between 5.6 and 6.0 N and was independent of air pressure. The difference between maximum adhesion force and adhesion force after buckling gives a reasonable window of operation for pick and place processes. High reversibility of the switching behavior is shown over 50 cycles in air and in vacuum, making the bioinspired switchable adhesive applicable for handling operations of fragile objects.

  14. Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface

    OpenAIRE

    Xia Pu; Guangji Li; Hanlu Huang

    2016-01-01

    ABSTRACT Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS)-embedded elastomeric stamping (PEES) method. Scanning electron microscopy (SEM) was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark s...

  15. SIMULATIONS OF FLOWFIELDS AROUND UNDERWATER APPENDED BODIES

    Institute of Scientific and Technical Information of China (English)

    Huang Zhen-yu; Cheng Hong-rong; Zhou Lian-di; Miao Guo-ping

    2003-01-01

    The numerical method which is based on flux difference splitting, LU decomposition, and implicit high-resolution third-order Essentially Non-Oscillatory (ENO) scheme was constructed for the efficient computation of steady state solution to three-dimensional incompressible Navier-Stokes equations in general coordinates. The flowfields over underwater axisymmetric bodies, full-appended axisymmetric bodies and axisymetric bodies with a ring-wing duct were simulated. The method is proved to be capable of predicting the circumferential-mean velocity distribution at model scale to the accuracy of around 3% of measured values, and of predicting some details of flow features, for example, the wake harmonics.

  16. The Future Deep Underwater Space Station

    OpenAIRE

    Jianjun Yao; Guilin Jiang; Rui Xiao

    2013-01-01

    The purpose of the study is to provide an idea of developing an underwater space station. Though the ocean covers about 71% of the surface of the Earth and holds tremendous amount of resources, it is still an unknown field for human beings. With the depletion of natural resources on the land, there is an urgent need to explore and exploit the ocean, but this process is constrained by the ocean engineering equipment and technology. The study proposed a sketch of a deep sea space station, which...

  17. Silent Localization of Underwater Sensors Using Magnetometers

    Science.gov (United States)

    Callmer, Jonas; Skoglund, Martin; Gustafsson (Eurasipmember), Fredrik

    2010-12-01

    Sensor localization is a central problem for sensor networks. If the sensor positions are uncertain, the target tracking ability of the sensor network is reduced. Sensor localization in underwater environments is traditionally addressed using acoustic range measurements involving known anchor or surface nodes. We explore the usage of triaxial magnetometers and a friendly vessel with known magnetic dipole to silently localize the sensors. The ferromagnetic field created by the dipole is measured by the magnetometers and is used to localize the sensors. The trajectory of the vessel and the sensor positions are estimated simultaneously using an Extended Kalman Filter (EKF). Simulations show that the sensors can be accurately positioned using magnetometers.

  18. Underwater Chaotic Lidar using Blue Laser Diodes

    Science.gov (United States)

    Rumbaugh, Luke K.

    The thesis proposes and explores an underwater lidar system architecture based on chaotic modulation of recently introduced, commercially available, low cost blue laser diodes. This approach is experimentally shown to allow accurate underwater impulse response measurements while eliminating the need for several major components typically found in high-performance underwater lidar systems. The proposed approach is to: 1. Generate wideband, noise-like intensity modulation signals using optical chaotic modulation of blue-green laser diodes, and then 2. Use this signal source to develop an underwater chaotic lidar system that uses no electrical signal generator, no electro-optic modulator, no optical frequency doubler, and no large-aperture photodetector. The outcome of this thesis is the demonstration of a new underwater lidar system architecture that could allow high resolution ranging, imaging, and water profiling measurements in turbid water, at a reduced size, weight, power and cost relative to state-of-the-art high-performance underwater lidar sensors. This work also makes contributions to the state of the art in optics, nonlinear dynamics, and underwater sensing by demonstrating for the first time: 1. Wideband noise-like intensity modulation of a blue laser diode using no electrical signal generator or electro-optic modulator. Optical chaotic modulation of a 462 nm blue InGaN laser diode by self-feedback is explored for the first time. The usefulness of the signal to chaotic lidar is evaluated in terms of bandwidth, modulation depth, and autocorrelation peak-to-sidelobe-ratio (PSLR) using both computer and laboratory experiments. In laboratory experiments, the optical feedback technique is shown to be effective in generating wideband, noise-like chaotic signals with strong modulation depth when the diode is operated in an external-cavity dominated state. The modulation signal strength is shown to be limited by the onset of lasing within the diode's internal

  19. Fault Diagnosis of Autonomous Underwater Vehicles

    Directory of Open Access Journals (Sweden)

    Xiao Liang

    2013-04-01

    Full Text Available In this study, we propose the least disturbance algorithm adding scale factor and shift factor. The dynamic learning ratio can be calculated to minimize the scale factor and shift factor of wavelet function and the variation of net weights and the algorithm improve the stability and the convergence of wavelet neural network. It was applied to build the dynamical model of autonomous underwater vehicles and the residuals are generated by comparing the outputs of the dynamical model with the real state values in the condition of thruster fault. Fault detection rules are distilled by residual analysis to execute thruster fault diagnosis. The results of simulation prove the effectiveness.

  20. Water waves generated by underwater explosion

    CERN Document Server

    Mehaute, Bernard Le

    1996-01-01

    This is the first book on explosion-generated water waves. It presents the theoretical foundations and experimental results of the generation and propagation of impulsively generated waves resulting from underwater explosions. Many of the theories and concepts presented herein are applicable to other types of water waves, in particular, tsunamis and waves generated by the fall of a meteorite. Linear and nonlinear theories, as well as experimental calibrations, are presented for cases of deep and shallow water explosions. Propagation of transient waves on dissipative, nonuniform bathymetries to

  1. Alexandria Underwater Museum For Sunken Monuments

    OpenAIRE

    Hafiz, Dalia O

    2011-01-01

    This thesis is a study of a journey in the deep mystery of the eastern harbor on the Mediterranean sea in the city of Alexandria. For Herodotus, the four major elements for civilizationâ s development overtime are water, air, land, and fire. In this project, the effort is made to connect three of the four elements within an architectural context: â Underwater museumâ . The building orientation, shape and location allow a discovery of the building elements and shape consequently while...

  2. Underwater welding using remote controlled robots. Development of remote underwater welding technology with a high power YAG laser

    International Nuclear Information System (INIS)

    As components in nuclear power plant have been periodically carried out their inspection and repair to keep their integrity, on radioactive liquid wastes storage facility, because of difficulty on their inspection by human beings, some are remained without inspection, and even when capable of inspection, conversion from human works to remote operations is desired from a viewpoint of their operation efficiency upgrading. For response to these needs, some developments on a technology capable of carrying out inspection of their inside at underwater environment and repairing welding with YAG laser by means of remote operation, have been performed. Remote underwater inspection and repair technology is a combination technology of already applied underwater mobile technique (underwater inspection robot) with underwater YAG laser welding technique which is recently at actual using level. Therefore, this technology is composed of an inspection robot and a repair welding robot. And, testing results using the underwater inspection robot and welding test results using the underwater repair welding robot, were enough preferable to obtain forecasting applicable to actual apparatuses. This technology is especially effective for inspection and repair of inside of nuclear fuel cycle apparatuses and relatively high dose apparatuses, and can be thought to be applicable also to large capacity tanks, tanks dealing with harmful matters, underwater structures, and so on, in general industries. (G.K.)

  3. Biomimetic tissue-engineered systems for advancing cancer research: NCI Strategic Workshop report.

    Science.gov (United States)

    Schuessler, Teresa K; Chan, Xin Yi; Chen, Huanhuan Joyce; Ji, Kyungmin; Park, Kyung Min; Roshan-Ghias, Alireza; Sethi, Pallavi; Thakur, Archana; Tian, Xi; Villasante, Aranzazu; Zervantonakis, Ioannis K; Moore, Nicole M; Nagahara, Larry A; Kuhn, Nastaran Z

    2014-10-01

    Advanced technologies and biomaterials developed for tissue engineering and regenerative medicine present tractable biomimetic systems with potential applications for cancer research. Recently, the National Cancer Institute convened a Strategic Workshop to explore the use of tissue biomanufacturing for development of dynamic, physiologically relevant in vitro and ex vivo biomimetic systems to study cancer biology and drug efficacy. The workshop provided a forum to identify current progress, research gaps, and necessary steps to advance the field. Opportunities discussed included development of tumor biomimetic systems with an emphasis on reproducibility and validation of new biomimetic tumor models, as described in this report.

  4. Underwater vehicle sonar self-noise prediction based on genetic algorithms and neural network

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-guang; SHI Zhong-kun

    2006-01-01

    The factors that influence underwater vehicle sonar self-noise are analyzed, and genetic algorithms and a back propagation (BP) neural network are combined to predict underwater vehicle sonar self-noise. The experimental results demonstrate that underwater vehicle sonar self-noise can be predicted accurately by a GA-BP neural network that is based on actual underwater vehicle sonar data.

  5. Pathogenesis of postoperative adhesion formation

    NARCIS (Netherlands)

    Hellebrekers, B.W.J.; Kooistra, T.

    2011-01-01

    Background: Current views on the pathogenesis of adhesion formation are based on the "classical concept of adhesion formation", namely that a reduction in peritoneal fibrinolytic activity following peritoneal trauma is of key importance in adhesion development. Methods: A non-systematic literature s

  6. Local elasticity and adhesion of nanostructures on Drosophila melanogaster wing membrane studied using atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Ryan, E-mail: rbwagner@purdue.edu [School of Mechanical Engineering, Purdue University, West Lafayette (United States); Brick Nanotechnology Center, Purdue University, West Lafayette (United States); Pittendrigh, Barry R. [Department of Entomology, University of Illinois, Champaign (United States); Raman, Arvind, E-mail: raman@purdue.edu [School of Mechanical Engineering, Purdue University, West Lafayette (United States); Brick Nanotechnology Center, Purdue University, West Lafayette (United States)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We studied the wing membrane of Drosophila melanogaster with atomic force microscopy. Black-Right-Pointing-Pointer We report the structure, elasticity, and adhesion on the wing membrane in air and nitrogen environments. Black-Right-Pointing-Pointer Results provide insight into the nature of the wing membrane enabling the development of biomimetic surface and micro air vehicles. - Abstract: Insect wings have a naturally occurring, complex, functional, hierarchical microstructure and nanostructure, which enable a remarkably water-resistant and self-cleaning surface. Insect wings are used as a basis for engineering biomimetic materials; however, the material properties of these nanostructures such as local elastic modulus and adhesion are poorly understood. We studied the wings of the Canton-S strain of Drosophila melanogaster (hereafter referred to as Drosophila) with atomic force microscopy (AFM) to quantify the local material properties of Drosophila wing surface nanostructures. The wings are found to have a hierarchical structure of 10-20 {mu}m long, 0.5-1 {mu}m diameter hair, and at a much smaller scale, 100 nm diameter and 30-60 nm high bumps. The local properties of these nanoscale bumps were studied under ambient and dry conditions with force-volume AFM. The wing membrane was found to have a elastic modulus on the order of 1000 MPa and the work of adhesion between the probe and wing membrane surface was found to be on the order of 100 mJ/m{sup 2}, these properties are the same order of magnitude as common thermoplastic polymers such as polyethylene. The difference in work of adhesion between the nanoscale bump and membrane does not change significantly between ambient (relative humidity of 30%) or dry conditions. This suggests that the nanoscale bumps and the surrounding membrane are chemically similar and only work to increase hydrophobicity though surface roughening or the geometric lotus effect.

  7. SPH and Eulerian underwater bubble collapse simulations

    Energy Technology Data Exchange (ETDEWEB)

    Swegle, J.W.; Kipp, M.E.

    1998-05-01

    SPH (Smoothed Particle Hydrodynamics) is a gridless Lagrangian technique which is appealing as a possible alternative to numerical techniques currently used to analyze high deformation impulsive loading events. Previously, the SPH algorithm has been subjected to detailed testing and analysis to determine the feasibility of using the coupled finite-element/SPH code PRONTO/SPH for the analysis of various types of underwater explosion problems involving fluid-structure and shock-structure interactions. Here, SPH and Eulerian simulations are used to study the details of underwater bubble collapse, particularly the formation of re-entrant jets during collapse, and the loads generated on nearby structures by the jet and the complete collapse of the bubble. Jet formation is shown to be due simply to the asymmetry caused by nearby structures which disrupt the symmetry of the collapse. However, the load generated by the jet is a minor precursor to the major loads which occur at the time of complete collapse of the bubble.

  8. Simplified Scheduling for Underwater Acoustic Networks

    Directory of Open Access Journals (Sweden)

    Wouter van Kleunen

    2013-01-01

    Full Text Available The acoustic propagation speed under water poses significant challenges to the design of underwater sensor networks and their medium access control protocols. Similar to the air, scheduling transmissions under water has significant impact on throughput, energy consumption, and reliability. In this paper we present an extended set of simplified scheduling constraints which allows easy scheduling of underwater acoustic communication. We also present two algorithms for scheduling communications, i.e. a centralized scheduling approach and a distributed scheduling approach. The centralized approach achieves the highest throughput while the distributed approach aims to minimize the computation and communication overhead. We further show how the centralized scheduling approach can be extended with transmission dependencies to reduce the end-to-end delay of packets. We evaluate the performance of the centralized and distributed scheduling approaches using simulation. The centralized approach outperforms the distributed approach in terms of throughput, however we also show the distributed approach has significant benefits in terms of communication and computational overhead required to setup the schedule. We propose a novel way of estimating the performance of scheduling approaches using the ratio of modulation time and propagation delay. We show the performance is largely dictated by this ratio, although the number of links to be scheduled also has a minor impact on the performance.

  9. Impacts of optical turbulence on underwater imaging

    Science.gov (United States)

    Hou, Weilin; Woods, S.; Goode, W.; Jarosz, E.; Weidemann, A.

    2011-06-01

    Optical signal transmission underwater is of vital interests to both civilian and military applications. The range and signal to noise during the transmission, as a function of system and water optical properties determines the effectiveness of EO technology. These applications include diver visibility, search and rescue, mine detection and identification, and optical communications. The impact of optical turbulence on underwater imaging has been postulated and observed by many researchers. However, no quantative studies have been done until recently, in terms of both the environmental conditions, and impacts on image quality as a function of range and spatial frequencies. Image data collected from field measurements during SOTEX (Skaneateles Optical Turbulence Exercise, July 22-31, 2010) using the Image Measurement Assembly for Subsurface Turbulence (IMAST) are presented. Optical properties of the water column in the field were measured using WETLab's ac-9 and Laser In Situ Scattering and Transmissometer (LISST, Sequoia Scientific), in coordination with physical properties including CTD (Seabird), dissipation rate of kinetic energy and heat, using both the Vector velocimeter and CT combo (Nortek and PME), and shear probe based Vertical Microstructure Profiler (VMP, Rockland). The strong stratification structure in the water column provides great opportunity to observe various dissipation strengths throughout the water column, which corresponds directly with image quality as shown. Initial results demonstrate general agreement between data collected and model prediction, while discrepancies between measurements and model suggest higher spatial and temporal observations are needed in the future.

  10. Hydrogel microphones for stealthy underwater listening.

    Science.gov (United States)

    Gao, Yang; Song, Jingfeng; Li, Shumin; Elowsky, Christian; Zhou, You; Ducharme, Stephen; Chen, Yong Mei; Zhou, Qin; Tan, Li

    2016-01-01

    Exploring the abundant resources in the ocean requires underwater acoustic detectors with a high-sensitivity reception of low-frequency sound from greater distances and zero reflections. Here we address both challenges by integrating an easily deformable network of metal nanoparticles in a hydrogel matrix for use as a cavity-free microphone. Since metal nanoparticles can be densely implanted as inclusions, and can even be arranged in coherent arrays, this microphone can detect static loads and air breezes from different angles, as well as underwater acoustic signals from 20 Hz to 3 kHz at amplitudes as low as 4 Pa. Unlike dielectric capacitors or cavity-based microphones that respond to stimuli by deforming the device in thickness directions, this hydrogel device responds with a transient modulation of electric double layers, resulting in an extraordinary sensitivity (217 nF kPa(-1) or 24 μC N(-1) at a bias of 1.0 V) without using any signal amplification tools. PMID:27554792

  11. Dynamic formation control for autonomous underwater vehicles

    Institute of Scientific and Technical Information of China (English)

    燕雪峰; 古锋; 宋琛; 胡晓琳; 潘毅

    2014-01-01

    Path planning and formation structure forming are two of the most important problems for autonomous underwater vehicles (AUVs) to collaborate with each other. In this work, a dynamic formation model was proposed, in which several algorithms were developed for the complex underwater environment. Dimension changeable particle swarm algorithm was used to find an optimized path by dynamically adjusting the number and the distribution of the path nodes. Position relationship based obstacle avoidance algorithm was designed to detour along the edges of obstacles. Virtual potential point based formation-keeping algorithm was employed by incorporating dynamic strategies which were decided by the current states of the formation. The virtual potential point was used to keep the formation structure when the AUV or the formation was deviated. Simulation results show that an optimal path can be dynamically planned with fewer path nodes and smaller fitness, even with a concave obstacle. It has been also proven that different formation-keeping strategies can be adaptively selected and the formation can change its structure in a narrow area and restore back after passing the obstacle.

  12. Image processing of underwater multispectral imagery

    Science.gov (United States)

    Zawada, D.G.

    2003-01-01

    Capturing in situ fluorescence images of marine organisms presents many technical challenges. The effects of the medium, as well as the particles and organisms within it, are intermixed with the desired signal. Methods for extracting and preparing the imagery for analysis are discussed in reference to a novel underwater imaging system called the low-light-level underwater multispectral imaging system (LUMIS). The instrument supports both uni- and multispectral collections, each of which is discussed in the context of an experimental application. In unispectral mode, LUMIS was used to investigate the spatial distribution of phytoplankton. A thin sheet of laser light (532 nm) induced chlorophyll fluorescence in the phytoplankton, which was recorded by LUMIS. Inhomogeneities in the light sheet led to the development of a beam-pattern-correction algorithm. Separating individual phytoplankton cells from a weak background fluorescence field required a two-step procedure consisting of edge detection followed by a series of binary morphological operations. In multispectral mode, LUMIS was used to investigate the bio-assay potential of fluorescent pigments in corals. Problems with the commercial optical-splitting device produced nonlinear distortions in the imagery. A tessellation algorithm, including an automated tie-point-selection procedure, was developed to correct the distortions. Only pixels corresponding to coral polyps were of interest for further analysis. Extraction of these pixels was performed by a dynamic global-thresholding algorithm.

  13. Doppler compensated underwater acoustic communication system

    Science.gov (United States)

    Raj, Anand; George, Binu; Supiya, M. H.; Kurian, James; Pillai, P. R. Saseendran

    2001-05-01

    Spread spectrum methods are used in communication systems to provide a low probability of intercept in hostile environments and multiple access capability in systems shared by many users as well as to provide high processing gain in channels where the transmitted signal is distorted by multipath effects. Such systems serve to be an effective tool for underwater telemetry environments, where multipath propagation effect and Doppler spreading is seen to be more predominant. This paper describes the implementation of a Doppler compensated underwater telemetry system based on CDMA technique. The system consists of multiple CDMA transmitters and a phase locked loop based carrier recoverable CDMA receiver. The effects of the Doppler shift can be compensated by the carrier recovery subsystem in the demodulator, based on PLL technique, which extracts the carrier frequency/phase and simultaneously demodulates the signal. The decision device in the receiver consists of a PN sequence generator as well as a bank of correlators, which are used to determine the data transmitted. The system simulation has been implemented in MATLAB. The advantage of this system is that multiple transmitting stations can transmit simultaneously to a central receiver, thereby increasing the system throughput.

  14. Hydrogel microphones for stealthy underwater listening

    Science.gov (United States)

    Gao, Yang; Song, Jingfeng; Li, Shumin; Elowsky, Christian; Zhou, You; Ducharme, Stephen; Chen, Yong Mei; Zhou, Qin; Tan, Li

    2016-08-01

    Exploring the abundant resources in the ocean requires underwater acoustic detectors with a high-sensitivity reception of low-frequency sound from greater distances and zero reflections. Here we address both challenges by integrating an easily deformable network of metal nanoparticles in a hydrogel matrix for use as a cavity-free microphone. Since metal nanoparticles can be densely implanted as inclusions, and can even be arranged in coherent arrays, this microphone can detect static loads and air breezes from different angles, as well as underwater acoustic signals from 20 Hz to 3 kHz at amplitudes as low as 4 Pa. Unlike dielectric capacitors or cavity-based microphones that respond to stimuli by deforming the device in thickness directions, this hydrogel device responds with a transient modulation of electric double layers, resulting in an extraordinary sensitivity (217 nF kPa-1 or 24 μC N-1 at a bias of 1.0 V) without using any signal amplification tools.

  15. Models and prototypes of biomimetic devices to architectural purposes

    Directory of Open Access Journals (Sweden)

    Silvia Titotto

    2014-12-01

    Full Text Available This paper presents some results of an ongoing interdisciplinary research about models and prototypes of biomimetic devices via installations and the focus of this paper is to outline this research role in architectural purposes as it perpasses the cultural and heritage contexts by being a way of understanding and living in the world as well as taking place in the world as devices or environments that pass on to future generations to use, learn from and be inspired by. Both the theoretical and the experimental work done so far point out that installations built with association of laser cutting and rapid prototyping techniques might be on the best feasible ways for developing and testing new technologies involved in biomimetic devices to architectural purposes that put both tectonics and nature as their central theme. 

  16. Surface Modifications of Support Partitions for Stabilizing Biomimetic Membrane Arrays

    DEFF Research Database (Denmark)

    Perry, Mark; Hansen, Jesper Schmidt; Jensen, Karin Bagger Stibius;

    2011-01-01

    Black lipid membrane (BLM) formation across apertures in an ethylene tetra-fluoroethylene (ETFE) partition separating two aqueous compartments is an established technique for the creation of biomimetic membranes. Recently multi-aperture BLM arrays have attracted interest and in order to increase...... with a high signal-to-noise (s/n) ratio. We demonstratesd this by reconstituting gA and α-hemolysin (α-HL) into BLM arrays. The improvement in membrane array lifetime and s/n ratio demonstrates that surface plasma polymerization of the supporting partition can be used to increase the stability of biomimetic...... BLM array stability we studied the effect of covalently modifying the partition substrate using surface plasma polymerization with hydrophobic n-hexene, 1-decene and hexamethyldisiloxane (HMDSO) as modification groups. Average lifetimes across singlesided HMDSO modified partitions or using 1-decene...

  17. Biomimetic strengthening polylactide scaffold materials for bone tissue engineering

    Institute of Scientific and Technical Information of China (English)

    XU Guofu; MOU Shenzhou; ZHOU Lingping; LIAO Susan; YIN Zhimin; CUI Fuzhai

    2007-01-01

    In this paper,a new polylactide(PLA)-based scaffold composite by biomimetic synthesis was designed.The novel composite mainly consists ofnano-hydroxyapatite (n-HA),which is the main inorganic content in natural bone tissue for the PLA.The crystal degree of the n-HA in the composite is low and the crystal size is very small,which is similar to that of natural bone.The compressive strength of the composite is higher than that of the PLA scaffold.Using the osteoblast culture technique,we detected cell behaviors on the biomaterial in vitro by SEM,and the cell affinity of the composite was found to be higher than that of the PLA scaffold.The biomimetic three-dimensional porous composite can serve as a kind of excellent scaffold material for bone tissue engineering because of its microstructure and properties.

  18. Sensing in nature: using biomimetics for design of sensors

    DEFF Research Database (Denmark)

    Lenau, Torben Anker; Cheong, Hyunmin; Shu, Li

    2008-01-01

    of sense organs in animals and illustrates how a formal search method developed at University of Toronto can be applied to sensor design. Design/methodology/approach – Using biomimetics involves a search for relevant cases, a proper analysis of the biological solutions, identification of design principles...... and design of the desired artefact. The present search method is based on formulation of relevant keywords and search for occurrences in a standard university biology textbook. Most often a simple formulation of keywords and a following search is not enough to generate a sufficient amount of useful ideas...... or the search gives too many results. This is handled by a more advanced search strategy where the search is either widened or it is focused further mainly using biological synonyms. Findings – A major problem in biomimetic design is finding the relevant analogies to actual design tasks in nature. Research...

  19. Design of biomimetic camouflage materials based on angiosperm leaf organs

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The micro structures and reflectance spectra of angiosperm leaves were compared with those of angiosperm petals. The study indicated that angiosperm leaf organs had identical micro structures and reflectance characteristics in the wave band of near infrared. Micro structures and compositions of leaf organs were the crucial factors influencing their reflectance spectra. The model of biomimetic materials based on angiosperm leaf organs was introduced and verified. From 300 to 2600 nm, the similarity coefficients of reflectance spectra of the foam containing water and Platanus Orientalis Linn. leaves were all above 0.969. The biomimetic camou- flage material exhibited almost the same reflectance spectra with those of green leaves in ultraviolet, visible and near infrared wave bands. And its "concolor and conspectrum" effect might take on reconnaissance of hyperspectral and ultra hy- perspectral imaging.

  20. Methods for biomimetic remineralization of human dentine: A systematic review

    OpenAIRE

    Chris Ying Cao; May Lei Mei; Quan-Li Li; Edward Chin Man Lo; Chun Hung Chu

    2015-01-01

    This study aimed to review the laboratory methods on biomimetic remineralization of demineralized human dentine. A systematic search of the publications in the PubMed, TRIP, and Web of Science databases was performed. Titles and abstracts of initially identified publications were screened. Clinical trials, reviews, non-English articles, resin-dentine interface studies, hybrid layer studies, hybrid scaffolds studies, and irrelevant studies were excluded. The remaining papers were retrieved wi...

  1. Biomimetics in Modern Organizations – Laws or Metaphors?

    OpenAIRE

    Markus Schatten; Miroslav Zugaj

    2011-01-01

    Biomimetics, the art and science of imitating nature and life for technological solutions is discussed from a modern organization theory perspective. The main hypothesis of this article is that there are common laws in nature that are applicable to living, social and likewise organizational systems. To take advantage of these laws, the study of nature's principles for their application to organizations is proposed - a process which is in product and technology design known as bionic creativit...

  2. Biomimetic supramolecular metallohosts for binding and activation of dioxygen

    OpenAIRE

    Sprakel, Vera Stefanie Irene

    2004-01-01

    Host-guest chemistry involves the binding of a specific substrate in a receptor via molecular recognition based on supramolecular interactions. Metal-containing derivatives of receptors for the selective supramolecular binding of dihydroxybenzene substrates, which receptors model oxygen binding enzymes both in structure and in function are described in this thesis with the ultimate goal to realize biomimetic catalysis. A PY2-appended receptor 1 and a TPA-appended receptor 2 and the bis-copper...

  3. Biomimetic Crawling Motion of Soft and Slender Gel-worm

    Institute of Scientific and Technical Information of China (English)

    Song Miao LIANG; Jian XU; Li Na ZHANG

    2006-01-01

    Inspired by the locomotion of terrestrial limbless animals, the present work attempt to study the motion of biomimetic system based on poly(vinyl alcohol)/dimethylsulfoxide gel. The system was operated in air by employing a non-contacted DC electric field. The results showed that the gel exhibited a long-range snail-like motion and had a very fast response rate.

  4. Flight mechanism and design of biomimetic micro air vehicles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper summaries the investigations on natural flyers and development of bio-mimetic micro air vehicles(MAVs)at NUAA,China,where the authors have led a group to conduct research for a decade. The investigations include the studies of low Reynolds number aerodynamics,unsteady computational fluid dynamics and flight control for the fixed-wing MAVs,the bird-like MAVs,the dragonfly-like MAVs and the bee-like MAVs.

  5. Neural Networks Integrated Circuit for Biomimetics MEMS Microrobot

    OpenAIRE

    Ken Saito; Kazuaki Maezumi; Yuka Naito; Tomohiro Hidaka; Kei Iwata; Yuki Okane; Hirozumi Oku; Minami Takato; Fumio Uchikoba

    2014-01-01

    In this paper, we will propose the neural networks integrated circuit (NNIC) which is the driving waveform generator of the 4.0, 2.7, 2.5 mm, width, length, height in size biomimetics microelectromechanical systems (MEMS) microrobot. The microrobot was made from silicon wafer fabricated by micro fabrication technology. The mechanical system of the robot was equipped with small size rotary type actuators, link mechanisms and six legs to realize the ant-like switching behavior. The NNIC generat...

  6. Flisht mechanism and design of biomimetic micro air vehicles

    Institute of Scientific and Technical Information of China (English)

    ANG HaiSong; XIAO TianHang; DUAN WenBo

    2009-01-01

    This paper summaries the investigations on natural flyers and development of bio-mimetic micro air vehicles(MAVs)at NUAA,China,where the authors have led a group to conduct research for a decade.The investigations include the studies of low Reynolds number aerodynamics,unsteady computational fluid dynamics and flight control for the fixed-wing MAVs,the bird-like MAVs,the dragonfly-like MAVs and the bee-like MAVs.

  7. Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges

    DEFF Research Database (Denmark)

    Habel, Joachim Erich Otto; Hansen, Michael; Kynde, Søren;

    2015-01-01

    In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs...... thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes....

  8. Underwater adhesion of abalone: The role of van der Waals and capillary forces

    Energy Technology Data Exchange (ETDEWEB)

    Lin, A.Y.M., E-mail: albertlin22@yahoo.com [Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093 (United States); Brunner, R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States)] [Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093 (United States); Chen, P.Y. [Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093 (United States); Talke, F.E. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States)] [Center for Magnetic Recording Research, University of California, San Diego, La Jolla, CA 92093 (United States); Meyers, M.A. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States)] [Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093 (United States)] [Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093 (United States)

    2009-08-15

    The observation of the pedal foot of the red abalone Haliotis rufescens reveals the presence of micrometer-scaled setae terminating in nanometer-sized cylindrical fibrils, with some resemblance to those found on the gecko foot. Atomic force microscopy (AFM) pull-off force measurements on a single seta are compared with theoretical estimates for van der Waals attraction obtained through the Johnson-Kendall-Roberts (JKR) equation, approximately 600 nN, and show agreement. The use of the JKR equation is justified through an analysis of the shape of the fibril extremities (parabolic) as well as their diameter ({approx}200 nm). Measurements under varying humidity conditions indicate that additional capillary interactions play a role, since the pull-off force increases with humidity. It is proposed that both van der Waals and capillary forces play a role in the attachment mechanism of H. rufescens, effectively enabling suction to reach its theoretical limit. Bulk pull-off force measurements on entire live animals yield an average detachment stress of 115 kPa, consistent with theoretical estimates. The setae and nanoscale fibril terminations enable compliance to surfaces with a variety of roughnesses, effectively sealing the interface, in addition to providing capillary and van der Waals forces.

  9. Measurements of optical underwater turbulence under controlled conditions

    Science.gov (United States)

    Kanaev, A. V.; Gladysz, S.; Almeida de Sá Barros, R.; Matt, S.; Nootz, G. A.; Josset, D. B.; Hou, W.

    2016-05-01

    Laser beam propagation underwater is becoming an important research topic because of high demand for its potential applications. Namely, ability to image underwater at long distances is highly desired for scientific and military purposes, including submarine awareness, diver visibility, and mine detection. Optical communication in the ocean can provide covert data transmission with much higher rates than that available with acoustic techniques, and it is now desired for certain military and scientific applications that involve sending large quantities of data. Unfortunately underwater environment presents serious challenges for propagation of laser beams. Even in clean ocean water, the extinction due to absorption and scattering theoretically limit the useful range to few attenuation lengths. However, extending the laser light propagation range to the theoretical limit leads to significant beam distortions due to optical underwater turbulence. Experiments show that the magnitude of the distortions that are caused by water temperature and salinity fluctuations can significantly exceed the magnitude of the beam distortions due to atmospheric turbulence even for relatively short propagation distances. We are presenting direct measurements of optical underwater turbulence in controlled conditions of laboratory water tank using two separate techniques involving wavefront sensor and LED array. These independent approaches will enable development of underwater turbulence power spectrum model based directly on the spatial domain measurements and will lead to accurate predictions of underwater beam propagation.

  10. Intelligent Navigation for a Solar Powered Unmanned Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Francisco García-Córdova

    2013-04-01

    Full Text Available In this paper, an intelligent navigation system for an unmanned underwater vehicle powered by renewable energy and designed for shadow water inspection in missions of a long duration is proposed. The system is composed of an underwater vehicle, which tows a surface vehicle. The surface vehicle is a small boat with photovoltaic panels, a methanol fuel cell and communication equipment, which provides energy and communication to the underwater vehicle. The underwater vehicle has sensors to monitor the underwater environment such as sidescan sonar and a video camera in a flexible configuration and sensors to measure the physical and chemical parameters of water quality on predefined paths for long distances. The underwater vehicle implements a biologically inspired neural architecture for autonomous intelligent navigation. Navigation is carried out by integrating a kinematic adaptive neuro‐controller for trajectory tracking and an obstacle avoidance adaptive neuro‐controller. The autonomous underwater vehicle is capable of operating during long periods of observation and monitoring. This autonomous vehicle is a good tool for observing large areas of sea, since it operates for long periods of time due to the contribution of renewable energy. It correlates all sensor data for time and geodetic position. This vehicle has been used for monitoring the Mar Menor lagoon.

  11. Biomimetic coating of calcium phosphate on biometallic materials

    Institute of Scientific and Technical Information of China (English)

    ZHANG Er-lin; YANG Ke

    2005-01-01

    The biomimetic coating process in comparison with other processes is reviewed. This processing shows advantages in the surface bio-modification, such as low cost and flexible processing, wide range of apatite composition and thickness, non-line-of-sight characteristic and possibility to coat polymers and porous implants. The bio-mimetic apatite coating is made up of larger number of globules with size of 1-5μm. Each globule is a group of numerous flakes with a size range of 100-200nm to 30μm in length and 0.1-1μm in thickness. In-vitro and in-vivo studies show that the biomimetic apatite coating can promote an early and strong bonding to bone or promote the bone in-growth into the porous structure, which will be beneficial to the cementless stable fixation of orthopaedic implants. Recently developed co-precipitation of a kind of protein molecules into the HA coating shows much promising.

  12. Bottom-Up Synthesis and Sensor Applications of Biomimetic Nanostructures

    Directory of Open Access Journals (Sweden)

    Li Wang

    2016-01-01

    Full Text Available The combination of nanotechnology, biology, and bioengineering greatly improved the developments of nanomaterials with unique functions and properties. Biomolecules as the nanoscale building blocks play very important roles for the final formation of functional nanostructures. Many kinds of novel nanostructures have been created by using the bioinspired self-assembly and subsequent binding with various nanoparticles. In this review, we summarized the studies on the fabrications and sensor applications of biomimetic nanostructures. The strategies for creating different bottom-up nanostructures by using biomolecules like DNA, protein, peptide, and virus, as well as microorganisms like bacteria and plant leaf are introduced. In addition, the potential applications of the synthesized biomimetic nanostructures for colorimetry, fluorescence, surface plasmon resonance, surface-enhanced Raman scattering, electrical resistance, electrochemistry, and quartz crystal microbalance sensors are presented. This review will promote the understanding of relationships between biomolecules/microorganisms and functional nanomaterials in one way, and in another way it will guide the design and synthesis of biomimetic nanomaterials with unique properties in the future.

  13. Management of adhesive capsulitis

    Directory of Open Access Journals (Sweden)

    Stupay KL

    2015-08-01

    Full Text Available Kristen L Stupay,1 Andrew S Neviaser2 1Tulane University School of Medicine, New Orleans, LA, USA; 2George Washington University Medical Faculty Associates, Washington, DC, USA Abstract: Adhesive capsulitis of the shoulder is a condition of capsular contracture that reduces both active and passive glenohumeral motion. The cause of adhesive capsulitis is not known but it is strongly associated with endocrine abnormalities such as diabetes. Diverse terminology and the absence of definitive criteria for diagnosis make evaluating treatment modalities difficult. Many treatment methods have been reported, most with some success, but few have been proved to alter the natural course of this disease. Most afflicted patients will achieve acceptable shoulder function without surgery. Those who remain debilitated after 8–12 months are reasonable candidates for invasive treatments. Here, the various treatment methods and the data to support their use are reviewed. Keywords: frozen shoulder, stiff shoulder, periarthritis, painful shoulder 

  14. Syndecans and cell adhesion

    DEFF Research Database (Denmark)

    Couchman, J R; Chen, L; Woods, A

    2001-01-01

    Now that transmembrane signaling through primary cell-matrix receptors, integrins, is being elucidated, attention is turning to how integrin-ligand interactions can be modulated. Syndecans are transmembrane proteoglycans implicated as coreceptors in a variety of physiological processes, including...... cell adhesion, migration, response to growth factors, development, and tumorigenesis. This review will describe this family of proteoglycans in terms of their structures and functions and their signaling in conjunction with integrins, and indicate areas for future research....

  15. Adaptive Decentralized Control of Mobile Underwater Sensor Networks and Robots for Modeling Underwater Phenomena

    Directory of Open Access Journals (Sweden)

    Carrick Detweiler

    2014-05-01

    Full Text Available Understanding the dynamics of bodies of water and their impact on the global environment requires sensing information over the full volume of water. In this article, we develop a gradient-based decentralized controller that dynamically adjusts the depth of a network of underwater sensors to optimize sensing for computing maximally detailed volumetric models. We prove that the controller converges to a local minimum and show how the controller can be extended to work with hybrid robot and sensor network systems. We implement the controller on an underwater sensor network with depth adjustment capabilities. Through simulations and in-situ experiments, we verify the functionality and performance of the system and algorithm.

  16. Development of Algorithms for Approaching and Docking Underwater Vehicle with Underwater Station

    Directory of Open Access Journals (Sweden)

    Gurenko B.V.

    2015-01-01

    Full Text Available Underwater vehicles (UV are widely spread nowadays. Their efficient application requires accompanying base ships or net of stations for technical servicing. Fast and energy-efficient docking is one of the key requirements for trouble-free operation. In this paper authors describe the research and development of algorithms for UV control system that allows docking with underwater station. The process is divided in two steps: moving to docking zone and vehicle positioning of station. First task includes development of path regulator. The proposed one features separation of control channels for simple adjustment and gives best results when multicoupling influence is low. Second task was solved on the basis of UV mathematical model. Developed control values were tested in simulation and proved themselves to be efficient. Authors give results of coordinate changes, control force modifications and deviation of velocity and orientation angles from the required values.

  17. Algorithms and analysis for underwater vehicle plume tracing.

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, Raymond Harry; Savage, Elizabeth L. (Texas A& M University, College Station, TX); Hurtado, John Edward (Texas A& M University, College Station, TX); Eskridge, Steven E.

    2003-07-01

    The goal of this research was to develop and demonstrate cooperative 3-D plume tracing algorithms for miniature autonomous underwater vehicles. Applications for this technology include Lost Asset and Survivor Location Systems (L-SALS) and Ship-in-Port Patrol and Protection (SP3). This research was a joint effort that included Nekton Research, LLC, Sandia National Laboratories, and Texas A&M University. Nekton Research developed the miniature autonomous underwater vehicles while Sandia and Texas A&M developed the 3-D plume tracing algorithms. This report describes the plume tracing algorithm and presents test results from successful underwater testing with pseudo-plume sources.

  18. A secure communication suite for underwater acoustic sensor networks.

    Science.gov (United States)

    Dini, Gianluca; Lo Duca, Angelica

    2012-01-01

    In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead.

  19. Energy Efficiency in Underwater Sensor Networks: a Research Review

    Directory of Open Access Journals (Sweden)

    V. Kanakaris

    2010-01-01

    Full Text Available In an energy-constrained underwater system environment it is very important to find ways to improve the life expectancy ofthe sensors. Compared to the sensors of a terrestrial Ad Hoc Wireless Sensor Network (WSN, underwater sensors cannotuse solar energy to recharge the batteries, and it is difficult to replace the batteries in the sensors. This paper reviews theresearch progress made to date in the area of energy consumption in underwater sensor networks (UWSN and suggestsfurther research that needs to be carried out in order to increase the energy efficiency of the UWSN system.

  20. Measuring In-Air and Underwater Hearing in Seabirds.

    Science.gov (United States)

    Crowell, Sara C

    2016-01-01

    Electrophysiological methods were used to measure the in-air hearing of 10 species of seabirds. There are currently no measures of the underwater hearing abilities of diving birds. In preparation for constructing a behavioral audiogram both in-air and underwater hearing, several species of diving ducks were raised. Because there is a considerable amount of literature on bird hearing in air, the technical setup and training methods were modeled on similar studies, with modifications to address the nature of the underwater sound field and the difficulty of the task for the birds.

  1. WODA Technical Guidance on Underwater Sound from Dredging.

    Science.gov (United States)

    Thomsen, Frank; Borsani, Fabrizio; Clarke, Douglas; de Jong, Christ; de Wit, Pim; Goethals, Fredrik; Holtkamp, Martine; Martin, Elena San; Spadaro, Philip; van Raalte, Gerard; Victor, George Yesu Vedha; Jensen, Anders

    2016-01-01

    The World Organization of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) prepared a guidance paper in 2013 on dredging sound, including a summary of potential impacts on aquatic biota and advice on underwater sound monitoring procedures. The paper follows a risk-based approach and provides guidance for standardization of acoustic terminology and methods for data collection and analysis. Furthermore, the literature on dredging-related sounds and the effects of dredging sounds on marine life is surveyed and guidance on the management of dredging-related sound risks is provided. PMID:26611082

  2. A Secure Communication Suite for Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Angelica Lo Duca

    2012-11-01

    Full Text Available In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead.

  3. Effects of Underwater Turbine Noise on Crab Larval Metamorphosis.

    Science.gov (United States)

    Pine, Matthew K; Jeffs, Andrew G; Radford, Craig A

    2016-01-01

    The development of marine tidal turbines has advanced at a rapid rate over the last decade but with little detailed understanding of the potential noise impacts on invertebrates. Previous research has shown that underwater reef noise plays an important role in mediating metamorphosis in many larval crabs and fishes. New research suggests that underwater estuarine noise may also mediate metamorphosis in estuarine crab larvae and that the noise emitted from underwater tidal and sea-based wind turbines may significantly influence larval metamorphosis in estuarine crabs. PMID:26611041

  4. Underwater 3D Reconstruction Based on Physical Models for Refraction and Underwater Light Propagation

    OpenAIRE

    Jordt, Anne

    2013-01-01

    In recent years, underwater imaging has gained a lot of popularity partly due to the availability of off-the-shelf consumer cameras, but also due to a growing interest in the ocean floor by science and industry. Apart from capturing single images or sequences, the application of methods from the area of computer vision has gained interest as well. However, water affects image formation in two major ways. First, while traveling through the water, light is attenuated and scattered, depending o...

  5. Task Allocation and Path Planning for Collaborative Autonomous Underwater Vehicles Operating through an Underwater Acoustic Network

    Directory of Open Access Journals (Sweden)

    Yueyue Deng

    2013-01-01

    Full Text Available Dynamic and unstructured multiple cooperative autonomous underwater vehicle (AUV missions are highly complex operations, and task allocation and path planning are made significantly more challenging under realistic underwater acoustic communication constraints. This paper presents a solution for the task allocation and path planning for multiple AUVs under marginal acoustic communication conditions: a location-aided task allocation framework (LAAF algorithm for multitarget task assignment and the grid-based multiobjective optimal programming (GMOOP mathematical model for finding an optimal vehicle command decision given a set of objectives and constraints. Both the LAAF and GMOOP algorithms are well suited in poor acoustic network condition and dynamic environment. Our research is based on an existing mobile ad hoc network underwater acoustic simulator and blind flooding routing protocol. Simulation results demonstrate that the location-aided auction strategy performs significantly better than the well-accepted auction algorithm developed by Bertsekas in terms of task-allocation time and network bandwidth consumption. We also demonstrate that the GMOOP path-planning technique provides an efficient method for executing multiobjective tasks by cooperative agents with limited communication capabilities. This is in contrast to existing multiobjective action selection methods that are limited to networks where constant, reliable communication is assumed to be available.

  6. From biological membranes to biomimetic model membranes

    Directory of Open Access Journals (Sweden)

    Eeman, M.

    2010-01-01

    Full Text Available Biological membranes play an essential role in the cellular protection as well as in the control and the transport of nutrients. Many mechanisms such as molecular recognition, enzymatic catalysis, cellular adhesion and membrane fusion take place into the biological membranes. In 1972, Singer et al. provided a membrane model, called fluid mosaic model, in which each leaflet of the bilayer is formed by a homogeneous environment of lipids in a fluid state including globular assembling of proteins and glycoproteins. Since its conception in 1972, many developments were brought to this model in terms of composition and molecular organization. The main development of the fluid mosaic model was made by Simons et al. (1997 and Brown et al. (1997 who suggested that membrane lipids are organized into lateral microdomains (or lipid rafts with a specific composition and a molecular dynamic that are different to the composition and the dynamic of the surrounding liquid crystalline phase. The discovery of a phase separation in the plane of the membrane has induced an explosion in the research efforts related to the biology of cell membranes but also in the development of new technologies for the study of these biological systems. Due to the high complexity of biological membranes and in order to investigate the biological processes that occur on the membrane surface or within the membrane lipid bilayer, a large number of studies are performed using biomimicking model membranes. This paper aims at revisiting the fundamental properties of biological membranes in terms of membrane composition, membrane dynamic and molecular organization, as well as at describing the most common biomimicking models that are frequently used for investigating biological processes such as membrane fusion, membrane trafficking, pore formation as well as membrane interactions at a molecular level.

  7. Biomimetic material strategies for cardiac tissue engineering

    International Nuclear Information System (INIS)

    Cardiovascular disease precedes many serious complications including myocardial infarction (MI) and it remains a major problem for the global community. Adult mammalian heart has limited ability to regenerate and compensate for the loss of cardiomyocytes. Restoration of cardiac function by replacement of diseased myocardium with functional cardiomyocytes is an intriguing strategy because it offers a potential cure for MI. Biomaterials are fabricated in nanometer scale dimensions by combining the chemical, biological, mechanical and electrical aspects of material for potential tissue engineering (TE) applications. Synthetic polymers offer advantageous in their ability to tailor the mechanical properties, and natural polymers offer cell recognition sites necessary for cell, adhesion and proliferation. Cardiac tissue engineering (TE) aim for the development of a bioengineered construct that can provide physical support to the damaged cardiac tissue by replacing certain functions of the damaged extracellular matrix and prevent adverse cardiac remodeling and dysfunction after MI. Electrospun nanofibers are applied as heart muscle patches, while hydrogels serve as a platform for controlled delivery of growth factors, prevent mechanical complications and assist in cell recruitment. This article reviews the applications of different natural and synthetic polymeric materials utilized as cardiac patches, injectables or 3D constructs for cardiac TE. Smart organization of nanoscale assemblies with synergistic approaches of utilizing nanofibers and hydrogels could further advance the field of cardiac tissue engineering. Rapid innovations in biomedical engineering and cell biology will bring about new insights in the development of optimal scaffolds and methods to create tissue constructs with relevant contractile properties and electrical integration to replace or substitute the diseased myocardium.

  8. Biomimetic material strategies for cardiac tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Molamma P., E-mail: nnimpp@nus.edu.sg [Health Care and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Venugopal, J. [Health Care and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Kai, Dan [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore (Singapore); Ramakrishna, Seeram [Health Care and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore)

    2011-04-08

    Cardiovascular disease precedes many serious complications including myocardial infarction (MI) and it remains a major problem for the global community. Adult mammalian heart has limited ability to regenerate and compensate for the loss of cardiomyocytes. Restoration of cardiac function by replacement of diseased myocardium with functional cardiomyocytes is an intriguing strategy because it offers a potential cure for MI. Biomaterials are fabricated in nanometer scale dimensions by combining the chemical, biological, mechanical and electrical aspects of material for potential tissue engineering (TE) applications. Synthetic polymers offer advantageous in their ability to tailor the mechanical properties, and natural polymers offer cell recognition sites necessary for cell, adhesion and proliferation. Cardiac tissue engineering (TE) aim for the development of a bioengineered construct that can provide physical support to the damaged cardiac tissue by replacing certain functions of the damaged extracellular matrix and prevent adverse cardiac remodeling and dysfunction after MI. Electrospun nanofibers are applied as heart muscle patches, while hydrogels serve as a platform for controlled delivery of growth factors, prevent mechanical complications and assist in cell recruitment. This article reviews the applications of different natural and synthetic polymeric materials utilized as cardiac patches, injectables or 3D constructs for cardiac TE. Smart organization of nanoscale assemblies with synergistic approaches of utilizing nanofibers and hydrogels could further advance the field of cardiac tissue engineering. Rapid innovations in biomedical engineering and cell biology will bring about new insights in the development of optimal scaffolds and methods to create tissue constructs with relevant contractile properties and electrical integration to replace or substitute the diseased myocardium.

  9. Plants and Animals as Concept Generators for the Development of Biomimetic Cable Entry Systems

    Institute of Scientific and Technical Information of China (English)

    Tom Masseiter; Uwe Scharf; Thomas Speck

    2008-01-01

    Many animals and plants have high potential to serve as concept generators for developing biomimetic materials and structures. We present some ideas based on structural and functional properties of plants and animals that led to the development of two types of biomimetic cable entry systems. Those systems have been realized on the level of functional demonstrators.

  10. A future of living machines?: International trends and prospects in biomimetic and biohybrid systems

    Science.gov (United States)

    Prescott, Tony J.; Lepora, Nathan; Vershure, Paul F. M. J.

    2014-03-01

    Research in the fields of biomimetic and biohybrid systems is developing at an accelerating rate. Biomimetics can be understood as the development of new technologies using principles abstracted from the study of biological systems, however, biomimetics can also be viewed from an alternate perspective as an important methodology for improving our understanding of the world we live in and of ourselves as biological organisms. A biohybrid entity comprises at least one artificial (engineered) component combined with a biological one. With technologies such as microscale mobile computing, prosthetics and implants, humankind is moving towards a more biohybrid future in which biomimetics helps us to engineer biocompatible technologies. This paper reviews recent progress in the development of biomimetic and biohybrid systems focusing particularly on technologies that emulate living organisms—living machines. Based on our recent bibliographic analysis [1] we examine how biomimetics is already creating life-like robots and identify some key unresolved challenges that constitute bottlenecks for the field. Drawing on our recent research in biomimetic mammalian robots, including humanoids, we review the future prospects for such machines and consider some of their likely impacts on society, including the existential risk of creating artifacts with significant autonomy that could come to match or exceed humankind in intelligence. We conclude that living machines are more likely to be a benefit than a threat but that we should also ensure that progress in biomimetics and biohybrid systems is made with broad societal consent.

  11. Biomimetically inspired short access to the 2-aminoimidazole-fused tetracyclic core of (+/-)-dibromoagelaspongin.

    Science.gov (United States)

    Picon, Sylvain; Tran, Huu Dau Elise; Martin, Marie-Thérèse; Retailleau, Pascal; Zaparucha, Anne; Al-Mourabit, Ali

    2009-06-18

    A six-step synthesis of the tetracyclic core of the natural compound (+/-)-dibromoagelaspongin, isolated from Agelas sp. Sponge, was achieved from the commercially available 5-aminopentan-1-ol, 2-trichloroacetylpyrrole, and 2-aminopyrimidine. Following a biomimetic inspired approach, successive oxidative reactions including the final DMDO biomimetic oxidation gave the interesting triaminomethane-fused core. PMID:19445491

  12. Acoustic Transmitters for Underwater Neutrino Telescopes

    CERN Document Server

    Ardid, Miguel; Bou-Cabo, Manuel; Larosa, Giuseppina; Adrián-Martínez, Silvia; Llorens, Carlos D

    2012-01-01

    In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to...

  13. Transducers and arrays for underwater sound

    CERN Document Server

    Butler, John L

    2016-01-01

    This improved and updated second edition covers the theory, development, and design of electro-acoustic transducers for underwater applications. This highly regarded text discusses the basics of piezoelectric and magnetostrictive transducers that are currently being used as well as promising new designs. It presents the basic acoustics as well as the specific acoustics data needed in transducer design and evaluation. A broad range of designs of projectors and hydrophones are described in detail along with methods of modeling, evaluation, and measurement. Analysis of projector and hydrophone transducer arrays, including the effects of mutual radiation impedance and numerical models for elements and arrays, are also covered. The book includes new advances in transducer design and transducer materials and has been completely reorganized to be suitable for use as a textbook, as well as a reference or handbook. The new edition contains updates to the first edition, end-of-chapter exercises, and solutions to select...

  14. Adaptive control of nonlinear underwater robotic systems

    Directory of Open Access Journals (Sweden)

    Thor I. Fossen

    1991-04-01

    Full Text Available The problem of controlling underwater mobile robots in 6 degrees of freedom (DOF is addressed. Uncertainties in the input matrix due to partly known nonlinear thruster characteristics are modeled as multiplicative input uncertainty. This paper proposes two methods to compensate for the model uncertainties: (1 an adaptive passivity-based control scheme and (2 deriving a hybrid (adaptive and sliding controller. The hybrid controller consists of a switching term which compensates for uncertainties in the input matrix and an on-line parameter estimation algorithm. Global stability is ensured by applying Barbalat's Lyapunovlike lemma. The hybrid controller is simulated for the horizontal motion of the Norwegian Experimental Remotely Operated Vehicle (NEROV.

  15. Broadband solid cloak for underwater acoustics

    CERN Document Server

    Chen, Yi; Liu, Xiaoning; Bi, Yafeng; Sun, Zhaoyong; Xiang, Ping; Yang, Jun; Hu, Gengkai

    2016-01-01

    Shielding an object to be undetectable is an important issue for engineering applications. Cloaking is the ultimate shielding example, routing waves around an object without mutual interaction, demonstrated as possible in principle by transformation and metamaterial techniques. Example applications have been successfully designed and validated for electromagnetic wave, thin plate flexural wave, thermal flux, and airborne sound. However, for underwater acoustics, the commonly used scheme based on meta-fluids with anisotropic density for airborne sound is unworkable since an acoustic rigid material is required with mass density three orders of magnitude higher than water. Material with such high density is impossible using even the heaviest metal, and may suffer from a narrow working frequency band even if realized with locally resonant techniques. An alternative solution was recently suggested based on solid pentamode material, which can be impedance matched with water and has anisotropic modulus. Here, we rep...

  16. Underwater Explosion Damage of Ship Hull Panels

    Directory of Open Access Journals (Sweden)

    K. Rarnajeyathilagam

    2003-10-01

    Full Text Available Underwater explosion is a major threat to ships and submarines in a war environment. The prediction of the mode and the extent of the failure is an essential step in designing for shock loading. The localised failure in a hull panel is severe compared to the global response of the ship. In this study, an attempt has been made to predict the response and failure modes of three types of hull panels (flat, concave, and convex. The shock loading on the hull panel has been estimated based on the Taylor's plate theory. The numerical analysis has been carried out using the CSAIGENSA (DYNA3D code that employs nonlinear finite element model.

  17. Silent Localization of Underwater Sensors Using Magnetometers

    Directory of Open Access Journals (Sweden)

    Jonas Callmer

    2010-01-01

    Full Text Available Sensor localization is a central problem for sensor networks. If the sensor positions are uncertain, the target tracking ability of the sensor network is reduced. Sensor localization in underwater environments is traditionally addressed using acoustic range measurements involving known anchor or surface nodes. We explore the usage of triaxial magnetometers and a friendly vessel with known magnetic dipole to silently localize the sensors. The ferromagnetic field created by the dipole is measured by the magnetometers and is used to localize the sensors. The trajectory of the vessel and the sensor positions are estimated simultaneously using an Extended Kalman Filter (EKF. Simulations show that the sensors can be accurately positioned using magnetometers.

  18. Transducers and Arrays for Underwater Sound

    CERN Document Server

    Sherman, Charles H

    2007-01-01

    This book is concerned with the theory, development and design of electroacoustic transducers for underwater applications, and is more comprehensive than any existing book in this field. It includes the basics of the six major types of electroacoustic transducers, with emphasis on the piezoelectric ceramic transducers that are currently most widely used. It presents the basic acoustics, as well as specific acoustic data, needed in transducer design and includes analysis of nonlinear effects in transducers. A large number of specific transducer designs, including both projectors and hydrophones, are described in detail as well as methods of modeling, evaluation and measurement. Analysis of transducer arrays, including the effects of mutual radiation impedance, as well as numerical models for transducers and arrays are also covered. The book contains an extensive Appendix of useful current information, including data on the latest transduction materials, and numerous diagrams that will facilitate its use by stu...

  19. Non-Liner Dynamics of Underwater Acoustics

    Science.gov (United States)

    Wiercigroch, M.; Badiey, M.; Simmen, J.; Cheng, A. H.-D.

    1999-03-01

    The non-linear dynamic behavior of acoustic wave propagation in an underwater sound channel, described by the Munk's classical sound speed profile perturbed by a single-mode internal wave, is studied using a parabolic ray theory. The amplitude and wavelength of this single-mode wave are used as the branching parameters in bifurcation analysis. The phase plane trajectory of the ray-based system can be periodic, quasi-periodic, and unstable. The regions of instability, located numerically via the bifurcation diagrams, are examined through a sequence of phase diagrams and Poincaré maps. Charts showing the maximum uninterrupted propagation distance reveal instances of anomalous vertical scattering of sound energy. Floquet multipliers were used to investigate instability of periodic orbits.

  20. Energy System selection for Small Underwater Vehicles

    Institute of Scientific and Technical Information of China (English)

    G.T.Reader; J.G.Hawley; 等

    1994-01-01

    The oceans cover almost three-quarters of the earth's surface and provide a highway for commerce or conquest and constitute a rich source of nutrients.materials and emergy.The exploration and exploitation of oceanic resources accelerated in the 1970s because of the merging offshore oil and gas industry.The extraction and national protection of these and other resources will increase rapidly in the next century and in support of these activities one of the most useful tools will be the small underwater vehicle.However,if these vehicles are to carry out the envisageed tasks in a cost-effective and mission-effective manner they will require high performance energy systems.A number of such systems are being developed and the problem arises as which one to select for a particular task.In this paper the development of software based techniques for the selection of energy systems is described.